University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\...

202

Transcript of University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\...

Page 1: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`
Page 2: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ����� �� �� ��� ����������� ��� ����� ����� � !"��#��$�%��!

& ����� �'#(�*)�+ ,-���/.��0��!"1*��!�. 23���'���546��� �7���8���

9 ���1:��!<;=�

>@?BADCFE(G�H�?BI�IKJML�HNGPO QRG�SUTNVBW"X0GPY

Z []\�^8_a`b_�_ac�d e-`f[U[g^ah=i%jlk$[]\�^'h^gmnka^ ^�joiNp'jnqM[gjlk�jri(st\K`vuwjl_Mj8xy\z

{=J%|"?BLr}r~�JMW} X�VB���tVB~�|DA�} JMLNO QM�bJMW<Q�JN?BW<��>�Xo��Qa�<VBCbVR�B����<J��(W����KJML Xr��}���VB���(A<J�J%W"XrCb?BW<�

� A<Xr}oL ?BC���?

��?��������6���R��

Page 3: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`
Page 4: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

����������� ����������������������������� �!�"���#�$%���&����'(������*)+,$-�������.���0/1�324����56��������7,89�����:�� ��;��$-�� ��24����56�<(�=����>&�@?�A���B$-��7C8D�����#�����E����8F?G �����H$-��<(��I&�������J?�A�����H$-��7K89�����L�� ����$%��MN�O�����

PRQTS"U*VJWUYX*Z�VJU1[O\�]^]3_a`�b�UYQ�U*b�Z*W c3d \�VCd�[D`Jb�U&S"U�[OU*]^]3d&e.S1fg c3h�ijc^`CS"\�V�k�VJc-S"c^h�lmZ�]3`Jb�d \�l bnh�d `.\�h�\TS"\�Z&]poq h�U*r�k�]3c-X4Z�Q�]^UR`Jb�d \�lsbnh�dsV�tuZ&]poq hTX1d tjk�V�U*b�U4h�S"c^Q�]3UC`Jb�d \�lsb�c3`,c-SF`�b�UvVJ\�]3Uxw

y U*V�`Jb�d ]^` y V�U&X�b�`.zJ{*| }s~���wj� �����D�s1�p����$ G ������j������MN��3� w

Page 5: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���������� ���� �� � �������� ���������

� b�UDeFd V���k�VJU&S"U*h `�U i c^hY`�b�c@S `�b�U&S�c-S c@S1o*`�d.`�b�U9Q�U&S�`Ad�[�ta_�� h�d&eC]3U&i�lsU,Z�h�iYQ=U4]3c3U�[Jo1d VJc3lsc3h�Z&]poU*r�X�U*k�` Z S Z X � h�d&eC]3U&i�lsU&i�c3h `�b�U,`�U*r `*o&Z&h�i `�b�UDtuZ&`�U*VJc-Z&] b�ZsS h�d ` Q�U*U*h0S"\�Q�tmc3`�`JU&i o*U*c^`�b�U4Vc3hueCb�d ]^UYd V.c3hjk�Z&V�`4oT[OdsV.Z i�U4l V�U4U Z&`C`�b�c@SFd VNZ�h _jd `Jb�U*VC\�h�c3WU*V�S"c3`�_w

! Z&\�] y Z"�#�U*V

$ Z*_�{4~�oA{*|s|&%

c

Page 6: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� �

� b�c-S `Jb�U&S�c-S c^h�WU&S�`�c^lZ�`JU&S `�b�U���\�U S"`�c^d h d�[AeCb�U*`�b�U4V [OU*U i�[Od VJeCZ�V�i6X1d h�h�U&X1`Jc3d h�c-S"` h�U*`�e,d V ��SX1d h�S�`�VJ\�X1`.Zv[O\�h�X�`�c3dsh�Z�] i�\�Z&]AV�d \�`�UYZ&V�X�b�c3`JU&X1`�\�V�U.`�d6c3tmk�]3U*tmU1h `��\�Z S�c3V�U4l \�]@Z�VCX�d l h�c3`�c^WUtuZ�k�k�c3h�lxS1oAS�\�X�b#ZsS�`�b�U6VJU&Z i�c^h�luZ&]3d \Ti d&[��(h�l ]^c-S�b�`�U*r `�d VY`Jb�U6l U*h�U*V�Z&`�c3dsh�d�[� h�l ]3c@S"bk�Z S�`R`JU*h�S"UYWU*VJQ�S1w

Ddsh�h�U&X�`�c3dsh�c-S�`Rtmd i�U*]-SCZ&V�U l U*h�U4V�Z�]^]3_uX�d h�S�c-i�U*VJU&i `JdjX�d h�S�`�c3`J\�`�U0Z ���� �3�3���s��� `�da`�b�UU&S"`�Z�Q�]^c-S"b�U&ini�\TZ�] V�d \�`�U6ZsX*X1ds\�h�`4o=eCb�c-X�b k�dxS"c3`�SR`�bTZ�`YS�U*k�Z�V�Z�`JUv[O\�h�X�`�c3dsh�Z�] tjU&X�b�Z&h�c-S�tuSZ�V�U�VJU��\�c3VJU&i `Jd X1d VJV�U&X�`�]3_ tuZ&k VJU*l \�]@Z�VuZ&h�i U*r�X�U*k�`�c^d h c3`�U4tuS1w �Rd&eFU*WU*V4oCZ:VJU*W�c^U*ed�[D`Jb�U6X1dsh�h�U&X�`�c3dsh�c-S�`C]3c^`�U*V�Z�`�\�V�UYV�U*WU Z�]-SF`Jb�Z�`.Q�d `Jb �$ ��� G 4$-� �p$ G ��� Z�hTi � G ��/1�^�6�$ ��� G *$-����p$ G ��� Q�U*`�eFU*U*h6VJU*l \�]-Z�V�SDZ�h�i U4r�X1U4k�`�c^d h�S bTZ WUCQ�U*U4h VJU&X1d V�i�U&i6c3h6]^U&S"c^d h�U&iaX1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��S�� `Jb�U&S"U���h�i�c^h�lSYi�U4tjd h�S�`�V�Z�`�U `�b�Z&`�`�b�U*V�U c-S�Z��\�Z&]3c3`�Z�`Jc3WU*]^_uS"c^tjc3]@Z�VCQ�d i�_�d�[U*W�c@i�U*h�X�UnS�\�k�k�d VJ`�c^h�l `Jb�U�U*r c-S"`JU*h�X1Uud&[aZLi�\TZ�]YV�ds\�`�U�c^h Q=ds`�b b�\�tuZ�h S"\�Q���U&X�`�S ����X1d h�h�U&X1`�c^d h�c@S"`Yh�U*`�e,d V ��S1w g \�VJ`�b�U4V�tjdsV�UoAc3`Yc@SN[Ods\�h�iL`�bTZ�` `Jb�UmX1d h�X�U*k�`�\TZ�]Ci c-S"`Jc3h�X�`�c3dsh`"_ k�c@X*Z�]^]3_�i�V�Z*eChLQ�U*`�e,U*U*h#X1dsh�h�U&X1`Jc3dsh�c-S�` Z&h�iLi�\TZ�]DV�ds\�`�Ujtmd i�U*]-S.c3h#`�b�UaV�U&X�U*h�`N]3c3`JU*V��Z�`�\�V�UuV�U&S�`�S6d h Z:X1dsh�[O\�S�c3d h d�[N]3U*WU4]-S1fa`�b�U �����*�4$-�� � S�c3h�ls]3UuV�ds\�`�U�d�[ Z#X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV �ac-SFU*VJV�d h�U*d \�S�]3_uX�d h `�V�ZsS"`JU&i eCc^`�bu`�b�U 24� ��1��$ G ��� � i \�Z�] V�ds\�`�UYd�[ `�b�UYi \�Z�] V�ds\�`�U`�b�U*dsV�_w

� 5 ���-� G � G � G ��� c@S(i�U*WU*]^d k�U&i�`�d i�U*`�U X1` `Jb�UFk�V�U&S�U*h�X1U,d�[ Z�i \�Z�]�VJd \�`JUCc3hY[OU*U&i�[OdsV�eCZ&V�iX1d h�h�U&X1`�c^d h�c@S"`Yh�U*`�e,d V ��S1w $ U*`Jb�d i�d ]^d lsc-X*Z&]Fc-SJS"\�U SvX�d h�S�c-i�U*VJU&i:c^h�X1]3\Ti�UaZ�i�c-SJX1\�SJS"c3dshLd�[b�d&e Z6i�\TZ�]AV�ds\�`�U X1ds\�]-iaQ=UYc^h�S"`�Z�h `�c-Z&`�U&iac3h�Z6i�c-S�`�VJc3Q�\�`JU&ijX1dsh�h�U&X�`�c3dsh�c-S�`CZ&V�X�b�c3`JU&X1`�\�V�U��k=dxS�S�c3Q�]^UCV�U*k�VJU&S"U4h�`�Z�`�c^d h�Z&]�tuZ&h�c [OU&S�`�Z&`�c3dsh�SAd�[ ZYi�\�Z�]�V�d \�`�U��`�b�U.Z�k�k�VJd k�VJc-Z&`�U*h�U S�S(d�[ S"`�Z��`�c-S�`�c@X*Z�](W c-S�\�Z�]^c �&Z&`�c^d h�`�U X�b�h�c!�\�U&SF[Od V U4r�Z&tjc3h�c^h�la`�b�Uac3h `�U*VJh�Z�] V�U4k�V�U&S�U*h `�Z�`Jc3dsh�Z�],S"kTZ X1Ud�[�X1dsh�h�U&X1`Jc3dsh�c-S�`9h�U*`�eFd V���S"� Z�h�ijb�d&e Q�U&S"`,`�d d k�U*V�Z&`�c^d h�Z&]3c �4U�`�b�UNX1dsh�S"`JV�\�X1`�S9d&[�# U*r�X1U*k��`�c3dsh�S�$ Z�h�i%# VJU*l \�]@Z�V�S�$�c3h�`�b�UaX1d h�h�U&X1`�c^d h�c@S"`.k�Z�V�Z i�c^l t�w'&k�U&X1c(� X*Z&]3]3_xo�c3`�c@S�Z�VJl \�U&in`Jb�Z�`U*r�X�U*k�`�c^d h�SCS�b�d \�]-i Q�U0i�U���h�U i eCc3`JbnVJU&S"k�U&X1`C`Jd `Jb�U t Z�k�k�c^h�laZ X�`�\�Z&]3]3_m]3U&Z&V�h�U&iuQ�_m`�b�Uh�U*`�eFdsV � o V�Z&`�b�U*VN`�b�Z&h*);Z S�c@SR`�b�UaS�`�Z&h�i�Z�V�i:k�V�Z X1`Jc-X1U�)neCc^`�b�VJU&S"k�U&X1`N`�d�Z�h Z�VJQ�c3`JV�Z�VJ_

c3c

Page 7: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

tuZ�k�k�c3h�l0X�b�dxS"U*huQ _j`�b�UvU4r�k�U*VJc3tjU*h `�U4V*w� S"c3h�l6`�b�UYk�VJd k�dS�U&intjU*`Jb�d i�d ]^d ls_o�`Jb�UYb�c-i�i U*hu\�h�c3`.S�k�Z X�U&SFd�[D`Jb�U ! ]-Z�\�`.Z�h�i $ X��

D]3U*]^]-Z�hTi z�{4| | }�aZ�hTi `�b�U y \�]3]3c^h�Z�VJc-Z�Z�h�i Db�Z�`JU*Vuz�{4| | }� [OU*U&i[Od V�eKZ�V�i X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��S )j`Jb�UY]-Z�`J`�U*V,d�[DeCb�c-X�b bTZ S.i�c-S�k�]-Z*_U&i `Jb�U S"`JV�d h�l U&S�`�i�c@S�S�d X1c-Z&`�c3dsh�c-S�`RU4W�c@i�U*h�X1U[Od V Zni�\TZ�]DV�ds\�`�UmS"du[�Z�V );Z�V�UaU*r�Z�tjc^h�U&ij[Od V `Jb�U6U*r c-S�`�U*h�X�U6d�[.i \�Z�]DtuZ&k�k�c3h�l tmU&X�bTZ��h�c-S�tuS1w��Rd6U*W c-i�U*hTX1UR[Od V.Z [O\�h�X�`�c3dsh�Z�] i \�Z�]AVJd \�`JU Z&V�X�b�c3`JU&X1`J\�V�U�c@S9[Od \�hTi w

� b�U Z&k�k�Z&V�U*h `C]-ZsX �6d&[DZ6i�\TZ�]AV�ds\�`�UNc3hu`�b�U y \�]3]^c3h�Z&V�c-ZYZ&h�i*Db�Z&`�U*VNz�{4| | }�Ch�U*`�e,d V �X�b�Z&]3]^U*h�l U SFd h�U6d&[F`Jb�U6X�d V�U0Z SJS"\�tjk�`�c3dsh�SRd&[,X1d lsh�c3`Jc3WUYh�U*\�V�d kTS"_�X�b�ds]3dsl _o hTZ�tjU*]^_ `Jb�Z�`i�c-SJS"d X1c@Z�`�c^d h�SaZ�VJUud h�]^_ Z�Q�]^Un`Jd#Z�V�c@S"Uuc3h S"_�S"`JU*tuSveCc^`�b Z�tjd i�\�]@Z�V6Z&V�X�b�c3`JU&X1`J\�V�Uw � dV�U&S�d ]3WUC`Jb�c-SDX1dsh���c@X1` q i�U*tjdsh�S"`JV�Z&`�UC`�bTZ�`*o eCc3`JbjZ S"\�� X1c3U4h�`DZ&tjd \�h�`(d&[ ]3U&S�c3dsh�c3h�l�o i�Z�t��Z�l U i U4r�U*tmk�]-Z&V�SRd&[�`Jb�U y \�]^]3c3hTZ�V�c@ZuZ�h�i Db�Z�`JU*VjzJ{*| |s}�� h�U*`�eFdsV � Z�VJUnZ&Q�]3Um`�d#i�c@S"k�]@Z _Q=ds`�b S"c3h�l ]3U�Z&h�i i�d \�Q�]3U�i�c-SJS"d X1c@Z�`Jc3d hTSEQ�U*`�eFU4U*h ���/*$3�p�J��1$3� �������4$ ���� ���J� S"U4`�S d�[ V�U*ls\��]-Z�VNZ�hTinU*r�X�U*k�`�c^d h�k�Z�`J`�U*VJh�S1w � b�c-SRVJU&S"\�]3`.V�U*WU&Z&]-S.ZEk�ds`�U*h `�c@Z�](tjU4`�b�d i�ds]3dsl c-X4Z�]�� Z*e c3h`�b�UNX1d h�h�U&X1`Jc3d h�c-S"`,]3U&S�c3dsh�c3h�lYk�Z&V�Zsi�c3lst `Jb�Z�`C]^c3tjc^`�SAc3`�S(`Jb�U*d VJU*`�c@X*Z�]�VJU*]3U*WsZ&h�X1U.`�d b \�tuZ&hi�c-SJS"d X1c@Z�`�c^d h;S"`�\Ti�c3U&S�w

� b�c3]3UY`Jb�U6X1\�V�V�U4h�`.V�U&S�\�]3`�SRi djh�d `.k�VJd�WU `�b�Z&`�X�d h�h�U X1`�c^d h�c@S"`.h�U*`�eFdsV ��S �=��I���� X�d h��S"`�VJ\�X1`YZ [O\�hTX1`�c^d h�Z&]Fi \�Z�](VJd \�`JUjZ&V�X�b�c3`JU&X1`J\�V�Uo�`�b�U*_�i�d;S"\�k�k=dsV�`Y`�b�UnzOb�c3`Jb�U*V�`Jdj\�h�S�\�Q��S"`�Z&h�`Jc-Z&`�U&i=�0k=dxS"c^`�c3dsh `�b�Z&`uX1dsh�h�U&X1`Jc3dsh�c-S�` h�U4`"e,d V���Sai�d h�d `mh�U*U&i `�d i�U4WU*]3dsk ZLi�\TZ�]V�d \�`�Uj`Jdnc3tmk�]3U*taU*h `���\TZ S"c^V�U*ls\�]-Z&V tuZ&k�k�c^h�lS�o(Z�hTi:b�U*h�X�U `Jb�Z�`aX1dsh�h�U&X�`�c3dsh�c-S�`Ytjd i�U*]@SX1d h�S�`�c^`�\�`JU Z W c-Z&Q�]3U X1dstjk�\�`�Z�`Jc3d hTZ�]AZ&]3`JU*V�h�Z&`�c^WU�`�da`�b�U i�\TZ�]AV�ds\�`�UY`Jb�U*d VJ_w

g c3h�Z&]3]3_xo*c3`Ac-S i�c@S�X1\�SJS"U&iYb�d&eL`�b�UFtjU*`Jb�d i�ds]3d lsc-X*Z&] X1d hTS"c-i U*V�Z&`�c3dsh�SAV�Z�c@S"U&iYc3hY`�b�c-SAeFd V��tuZ*_ Q�URk�V�d��T`�Z�Q�]3_mZ�k�k�]^c3U&i `Jd `Jb�URVJU&Z SJS"U&SJS"tjU4h�`(d&[AU*W c-i U*h�X1UF[OdsVFi \�Z�] V�d \�`�UC[O\�h�X1`Jc3d hTZ�]Z�V�X�b�c^`�U&X1`J\�V�U S9c3h ��� 56�� X1d lsh�c3`Jc3WUYS�_�S�`�U*tuS�w

c3c^c

Page 8: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �� � � � ��� � ��� �� � �

���������� ���� zJ{*| |�����w��Rd h $ `aX*Z�VJUutuZ�VJl c3hTSvb�U*]^kLQ�ZsX � k�V�dsk�Z�lxZ�`Jc3d h ]3U&Z&V�hLU4r�X1U4k�`�c^d h�S�wq h � w ��i�Z&tuS����(w &`JU*V�]^c3h�l#z �Di�S�w ��o�� � G 1���J�$-� ��� G 2j�-����� ��� �N� ������� �B$-�� ! G $-���" G ��2&��������1� G �#�N����$ $,*$-� ��%�� �"���^�B$ ������1� o(k�kAw6{*}s|��J{'&(&�w &c^h�lZ&k=dsV�Uf � d VJ]-i & X�c3U*h��`�c(� X w

���������� ����) +*-,).'/0��� �12�3 54768,393�.( �:;� z�{*|s| }��w �(r�X1U*k�`Jc3d ha]3U Z�V�h�c3h�l Q�_aQ�Z X � k�V�dsk�Z��lZ&`�c3dshAf � h�U*e U*V�VJd VF[O\�hTX1`�c^d hAw q h ! w<� U*d h�l�� $ w<=Z�Q�VJcDz �Di�S�w ��o>� � G 1���J�$-�s��� G 2�����.+ G �������?�N� ���p�J� �B$-�� " G ��2&��������1� G �A@ ��� ��� �B@ ����8 G ��>*� o�k�kAwC{s{DC��J{D� { w &_�i�h�U*_xo�R\�S�`�V�Z&]3c@Z�f &_�i�h�U*_ � h�c^WU*V�S�c3`�_ �(]3U&X�`�V�c@X*Z�] �(h�l c^h�U*U*VJc3h�l�w

���������� ����) +�FE�,)939),3G�.( IHI�3 I4J6K,39)L.( �:I� zJ{*|s| }���w � b�U � �M��� � U*h�X�d i�U*V*f � tuZ�`J`�U*V d�[V�U*k�V�U&S�U*h�`�Z�`Jc3d h w q h &�wIN.c3U*]^U*hO� y w�PYZ�k�k=U4h z �Di�S�w �Q� � G 1���J�$-� ��� G 2a�����R%�������� ���� ��$ G ��� � " G ��2&��������1� G �S�N���p$ $,4$-� �>@ ��� ��� �@ ���p8 G ��>*�UTV% " �W@W@2X Y�Z\[��N5v�������J��5 ok�kAw % %]&�� %&%�^w y U*VJ]3c3h f &k�VJc3h�lsU*V��3_DU*V�]@Z�l�w

*�,3.'/`L�a �12�3 ����������� ;�b�3 I4768,393�.( �:;� z�{*|s| }��w � VJV�dsV S"c^l h�Z&]-S�onU*r�X1U*k�`Jc3d hTS1ouZ�hTiQ�Z X � k�V�dsk�Z�lxZ�`Jc3d h w q h %������������ �p$ G ��� �c! G $-� � " G ��2&��������1� G �d@ �����J� �b@ ����8 G ��>*�TV%e! " @f@gX Y�Z\[R@Y�*� G �s� o�k�kAw %a^ }�� %a^`h w q ����� ,Z&`�Z&]3d l �R\�taQ�U*VC|s} ��}s}&%s}���~ w

���������� ����) +4J6K,39)L.( �:I� zJ{*|s| } Z��w �Rh Z�h�c^tuZ�`JU&i#S"`�\Ti�_:d&[.]3U&Z&V�h�c^h�l�i _�h�Z&tjc-X4SRc3h`�b�U {'& �M����{i& U4h�X1d i�U*V4w � U X�bAw;j U4kAwI��C]&�o�.U*k�Z�VJ`�tjU4h�`(d&[�Dd tjk�\�`�U*V & X�c3U*h�X�Uo � b�U� h�c^WU*V�S�c3`�_ d&[�k.\�U*U*h�S�]-Z&h�i o �R\�S�`�V�Z�]3c@Z�w

���������� ����) +4J6K,39)L.( �:I� zJ{*|s| }�Q ��w �Rh Z�h�c3tuZ&`�U&i�S�`�\�i�_#d�[.]^U&Z�VJh�c3h�lni _�h�Z&tjc-X4SRc3h`�b�Um{'& �M����{i&nU*h�X�d i�U*V?l W�c@i�U*d(m�w � { %��%tmc3h \�`�U Z�h�c3tuZ&`�U&ijW c-i�U*d�o=k�V�U&S�U*h�`JU&inZ&` � b�Ug c3V�S"` y VJc-S�Q�Z�h�U � d V ��S"b�d k dsh �RU4\�V�Z&] �RU*`�eFdsV ��Snz y VJc-S�Q�Z�h�Uxoc= \�h�U {*|s| }�uZ�hTiZ�`�`Jb�U q h�`JU*V�hTZ�`�c^d h�Z&] Ddsh�[OU*VJU*h�X1U d h �RV�`Jc � X1c@Z�] �RU4\�V�Z&] �RU4`"e,d V���SYz �Rt S"`�U4V�i�Z&t�o

c3W

Page 9: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

&U*k�`JU*taQ=U4Vn{4| | }��w �RWsZ�c3]@Z�Q�]^U�Q�_ d V�i�U*Vj[OV�dst `�b�UO�RU4k�Z�VJ`�tjU*h `jd&[�Dd tmk�\�`�U4V& X1c^U*h�X1Uo � b�U � h�c3WU*V�S"c3`�_6d&[�k.\�U*U*h�S�]-Z&h�i oBk.\�U4U*h�S"]@Z�h�i &x~a^`� o �R\�S�`�V�Z�]3c@Z�w

���������� ����) +�FE�,)939),3G�.( IHI�3 I4J6K,39)L.( �:I� zJ{*|s|]&���w � b�U {*~ ~s~�� ���J{*~s~ ~ U*h�X�d i�U*V*f �tuZ�`J`�U*V,d�[�V�U*k�V�U&S�U*h�`�Z�`Jc3d h w @ ��� ��� �@ ���p8 G ��>�� G ���B��7�� z %��o %��a^ � % }`&�w

���������� ����) +*����B/���+ �2�3 �� �B�`�`,3.( �� �3 I�W���`��,��5.���+ �HI�3 �H /`��G�9)L.( �� �3 �6KE5,V/`��.D,��5 �g�) �4 6K,39)L.( :I� zJ{*| |`&���w � S�c3h�lYQ�d `J`�]^U*h�U&X ��S c3h6[OU*U&i�[OdsV�eCZ&V�i6h�U*`�eFdsV ��S(Z SZji�c^tjU*h�S�c3d h�V�U&i \�X1`�c^d h�`JU&X�b�h�c!�\�Uf �.k�k�]3c@X*Z�`Jc3dshn`�dudsk�`�c^tjc-SJZ�`�c^d h�k�V�dsQ�]3U*t S1w q h� w .w � S"dsc � � wL�Rd&eCh�SCz �Di�S1wB��o�� � G 1���J�$-� ��� G 2.�����,+,$ 2������N� ������� �B$-�� " G ��2&��������1�G �S@ �����J� �>@ ����8 G ��>*� o k�k wv{ � |���{4}(��w � b�U � h�c^WU*V�S�c3`�_6d�[ kR\�U*U*h�S�]-Z�hTi o �.\�S"`JV�Z�]^c-Z f�RU*k�Z&V�`JtjU*h `9d&[ �(]3U&X�`�V�c@X*Z�] Z&h�i*Ddstjk�\�`JU*V��(h�l c^h�U*U*VJc3h�l�w

���������� ���� zJ{*| |`&���w�NRdd iatjd i�U*]@S d&[ b \�taQ�]3UDdsV�c3lsc3h�S�w q h?=�w � c3]3U S1o .w��AZ�`Jc3tjU*V4o(� .w&`�U4WU*h�SYz �Di�S1wB��oW" G �3�^�J1�"�J� � �1�������,24� G 5 ��� � 5R� G �4$-��5 G � " G ���=�J��p$ G ��$ ����� G ������ �m���� � � � �� G � G ��� o k�k wn{*~����J{*~`&�w � b�U � h�c^WU*V�S�c3`�_ud�[ck.\�U4U*h�S"]@Z�h�i o �.\�S"`JV�Z�]^c-Z fDd tjk�\�`�U*V�& X1c^U*h�X1UF�.U*k�Z�VJ`�tjU4h�`4w � U&X�bAw+jCU*kAw+�(Cs|�w

W

Page 10: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ��� �� ����� ��� ��� �

� b�U�eCV�c^`�c^h�lYd�[ `�b�c-S9`Jb�U&S�c-S1oeCb�c^]3UNi�U*tuZ&h�i�c^h�l Z�h�ijS�d tjU4`�c3tmU&S S�`�VJU&S�Sp[O\�]po b�Z SD]3U&i6tjU.`�dZ�k�k�VJU&X1c@Z�`�U6U4WU*h�tjd VJU6`�b�U6[OV�c^U*h�i�S�oAV�U*]@Z�`�c^WU&S�Z&h�i:X�d ]3]^U&Z�ls\�U&S�eCb�d�b�Z*WU6b�U*]3k�U&i o S�\�k��k=dsV�`JU&i o dsV ��\�S�`��U4k�`AtjUDSJZ�h�UKi�\�V�c^h�l.`�b�U,]3d h�lRk�VJd X1U&SJS d&[Ai V�Z [O`Jc3h�l�o�eCVJc3`Jc3h�l�o�VJU*`�b�c^h � c3h�l�oZ�h�iuV�U*eCVJc3`�c^h�l�w

g c3V�S�`Cd�[KZ�]^] q `Jb�Z�h �uta_jS�\�k�U*V�W c-S�d V4o>=Z&h�U*` � c3]3U S1o�[Od V ��V�S"`.c3h `�V�d i \�X1c3h�l tjUN`�da`�b�U[�Z S�X�c3h�Z&`�c3h�l eFdsV�]@i d�[�Ddsh�h�U&X1`Jc3dsh�c-S�t c^hn{4| | ~ w �RU*V,X1VJc3`Jc-X*Z&]�V�U&Zsi�c3h�lSFd�[ ta_6i V�Z [O`�S1o b�U*VU*r�k�U*VJ`(b�U*]^kAo Z�h�i6`�b�URU*hTX1d \�V�Z�lsU*tjU*h `DS"b�URb�ZsS(l c3WU4h tjU,d&WU*V(`�b�URk�ZsS"`D[Od \�VD_U&Z&V�S(b�Z*WUQ=U4U*hjc3h WsZ�]^\�Z�Q�]^Uw �.U*VFc^h�S"c@S"`�U4h�X1U.`�b�Z&`CZ�]^] b�U4VCS"`J\�i�U*h `�S # k�\�Q�]3c@S"bjdsVCk=U4V�c-S�b $b�Z SFb�U*]3k�U&itjUYc3hneKZ*_�SC`�b�Z&` q Z�t S"`Jc3]3] X�d \�h `�c^h�l�w �R\�V�c^h�lU=Z&h�U*` $!S�S�Z&Q�Q�Z&`�c-X4Z�](c^hn`�b�U6S"U X1d h�inbTZ�] [d�[K{*| |`&�o>N.\�_ &xtjc3`Jb6eCZ S � c3hTi U*h�ds\�l bu`�d6ls\�c-i U�tjU.k�Z�`Jc3U*h `�]^_6`�b�VJd \�lsb `Jb�U�tjc^h�U���U4]-i�Sd�[�`�b�U&S�c-SFeCVJc3`�c^h�l�w

$ _�S�`�\�i�U4h�`YX�d ]3]^U&Z�ls\�U&SCk�V�d&W c-i�U i tjUYeCc3`Jbnta\�X�b d&[,`�b�U c3h�S�k�c3V�Z�`�c^d hn[OdsV�`�b�U c-i�U Z SZ�h�i e,d V � k�VJU&S"U4h�`JU&i b�U4V�Uf &`�U4WU ! b�c3]^]3c^k�S1o &c3tmd h �RU*h�h�c-S1o jRZ*_ tjd h�i � c-S�`�U*V4o�= \�]3c^U&`�U*eKZ�VJ`*o Z�h�intuZ&h�_md `�b�U*V�SCc3h�`�b�U Dd tjk�\�`�U*V�& X1c^U*h�X1U Z�hTi ! S�_�X�b�ds]3d ls_�i�U*k�Z&V�`�tmU*h�`�S1w��SFeFU*]^]po q bTZ WUNk�V�d���`�U&ijlsV�U&Z&`�]3_a[OV�d t z%U �OtuZ�c^]%��i�c@S�X1\�SJS"c^d h�SFeCc^`�buV�U&S�U&Z�V�X�b�U*V�SDc3hud `Jb�U*V��U*]-i�SCZ�h�i��4d V�c^hud `�b�U*VCk�Z�VJ`�SCd�[D`Jb�UYeFdsV�]-i f �Rc@X ��DbTZ�`�U4V*o $ Z�r Dds]3`�b�U&Z�VJ`*o q Z�h ��Z*_U&S�o� Z&V�V�U4h & Z&V�]^Uo�PYZ��*\�b�c3VJdUP�d b�Z&V�Z�o�Z�h�i ! Z&\�] $ \�h�V�d�w'� Q�c^l `Jb�Z�h ��S�c-SNi�\�U6`�dg��Z*W c-i! ]@Z�\�`�d�[ ,Z�VJh�U*l c^U $ U*]3]^d h � h�c^WU*V�S�c3`�_o*eCb�d Z�]3]^d&eFU&iYtjU,Z X*X1U S�S `Jd�b�c-SA`�V�Z�c^h�c3h�l���]3U&S Z�hTi��U*]-i U&i ta_6U*h�i�]^U&S�SFk�VJd X1U&i�\�V�Z�] �\�U&S�`�c^d h�SFeCc^`�buV�U*t Z�V �sZ&Q�]3U.k�Z�`Jc3U*hTX1Uw � bTZ�h �ub�U&Z*WU*hTS[Od VC`�b�U q h `�U*VJh�U*`4w

q S�c3h�X1U4V�U*]^_R`Jb�Z�h �N`�b�U Ddstjk�\�`JU*V &�X1c3U*hTX1UI�.U*k�Z�VJ`�tjU4h�` Z�`A`�b�U � h�c3WU*V�S"c^`"_,d�[ k.\�U*U*h�S �]-Z�hTi o��R\�S"`JV�Z&]3c-Z oF[Od Vj`Jb�U $,�����a1�B����� X1d tmk�\�`�c^h�l�oKZ X*X1dstjtjd i�Z&`�c^d h Z&h�i ��h�Z&h�X1c@Z�]�VJU �S"d \�V�X1U&SD`�b�Z&`CeFU*VJU�l U4h�U*V�ds\�S"]^_ k�V�d&W�c@i�U&i6`�d6tjU.d&WU*VD`�b�U &6_U&Z�V�S9d�[ ta_6X4Z�h�i�c@i�Z�`J\�V�Uxw qZ�t U S"k�U&X1c@Z�]3]^_�c3hTi�U*Q�`JU&i [OdsV(`�b�U,`�V�Z WU4] [O\�h�i�c^h�l�`�bTZ�`DZ&]3]3d&e,U&ivtjUD`JdYZ�`J`�U*h�i6Z&h�i6k�V�U&S�U*h `k�Z�k�U*V�S Z�`6c^h�`JU*V�hTZ�`�c^d h�Z&],X1d h�[OU4V�U*h�X�U&S�c3h =Z�k�Z&h Z&h�i � b�U �RU*`�b�U*V�]@Z�h�i�S�o Z S eFU4]3]DZsS6Z�`

W c

Page 11: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

h�Z�`Jc3d hTZ�]�X1d h�[OU4V�U*h�X�U&S9c^h*&x_�i�h�U*_o $ U4]3Q�d \�VJh�Uo ,Z�h Q=U4V�V�ZaZ�hTi �RdsQ�Z�VJ`*w$ _ S�c-S"`JU*V $ Z�VJc-Z&h�h�UneKZ S � c3hTi U4h�d \�lsb `�d i V�d k U*WU*VJ_�`Jb�c3h�l#Z&h�i k�VJdd�[OV�U Z i `�b�c-S

`�b�U&S�c-S.Z�`YZatjd tjU4h�` $ S9h�d `�c@X1Uw y c3la`�bTZ�h ��SYZ�V�U0i�\�U6`Jdjt _a`�eCc3h�Q�V�ds`�b�U*V j c@X � [OdsV�]3U S�S`�Z�h�l c3Q�]3U b�U*]3kAfKZ # lsdd i:`�Z&] � c3h�la`�d�$=eCb�U4h q h�U*U&i�U i c3`.tjdxS"`*w q X*Z�h�b�d h�U&S�`�]^_nSJZ*_ `Jb�Z�`c [ c3`CeKZ S�h $ `F[OdsVRb�c^t�o`�b�c@SCX1d \�V�S"UYd&[DS�`�\�i�_ue,d \�]@i h�U*WU*VFbTZ WUNQ=U4U*h�S"`�Z&V�`JU&i o�ta\�X�ba]3U S�S��h�c-S�b�U&i w

�.d�e,U*WU*V4o=ta_ul V�U Z�`�U S"` i�U*Q�`Y]^c3U&SReCc^`�b�ta_uQ=U S"`�[OV�c^U*h�i oAeFdsV � �%t Z�`�U0Z�h�i#h�U*e eCcB[OUDb�U*V�_ ]po&eCb�dYb�ZsS Q�U*U4h6`�b�U*VJUFQ _Yt _YS�c-i�UF[OVJd t i�Z*_ d h�UoX*Z���ds]3c^h�l�Z&h�iaX*Z�VJU&S�S�c3h�l�o \�V�lsc3h�ltjU�d h o Q�Z X � c3h�lad�� eCb�U*h q h�U*U&i�U i `�c^tjUo�Z�h�inQ�U*c^h�l `Jb�U*VJU eCb�U*h q h�U*U&i U&i b�U4VRtjdxS"`4wq `Cc@SF`�d6b�U4VC`�b�Z&` q i�U&i�c@X*Z�`JU�`�b�c@SF`�b�U S"c-S�w

W�c^c

Page 12: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

W c3c^c

Page 13: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� �������� �

H /`��/0��� �B/������?�`,��,��5�<9),V/ � ,

5.'/0�]���(/ ,),

*-,).i/ � � �����93,�����/0, ���. ,��

�]� �����?9) ������ �B/`. ��,

� ��/` �/`. ,��

*-,).i/ � ����,������`�. ��,),3,

*-,).i/ � ������593�. ����,3,

� � �B/0� � �����(/`, �� �{sw3{ & X1d k�U d�[�`�b�U � b�U&S�c-S! � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � h{sw � � b�U&S"[email protected]*V�W c3U*e% � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^

& �RE5(')�5��9�1 ����/`(��E� ���� ���� w3{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { {� w � y Z X ��lsV�d \�h�i � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D�� w } � b�U � b�U*d VJ_ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*}� w & j U&X�U*h�` �RU*WU*]^d k�tmU*h�`�S+ " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {]^

, �RE5-� �� ����(/0, ���,).'/.�RE���939) ���B �0/} w3{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*|} w � ! Z S�` � U*h�S�U) $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � � ~

c3r

Page 14: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

} w } j U&Zsi�c3h�l � U*r ` �R]^d \�i " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � � }} w & �Rc-SJX1\�S�S�c3dsh $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � �(C} w % � h�Z�hTS"eFU4V�U&i2k.\�U&S�`�c3dsh�S # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � � |

� � ��, �� ����.� �� � � � ������(/`,���5,3.'/ ' ����9�1 ����/`�� ,��&�w3{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � }�{&�w � kR\�U&S"`Jc3d h�c3h�l6`Jb�U6PRQ W c3d \TS�� " # " � $ � $ � $ � � $ � " # " � $ � $ � � }(�&�w } q hTi�c3VJU&X1` �(W c-i�U4h�X1UR[OdsV�Z��R\TZ�];j ds\�`�U � $ � $ � � $ � " # " � $ � $ � � }]&

&�w } w3{ �Rds\�Q�]^U6i�c@S�S"d X�c-Z�`Jc3dsh�S # " � $ � $ � $ � � $ � " # " � $ � $ � � }&%&�w & �Rc-SJS"d X1c@Z�`�c^d h�SCc3h Ddsh�h�U&X1`Jc3dsh�c-S�` �RU*`�eFdsV ��S $ � � $ � " # " � $ � $ � � }a^

&�w &�w3{ P.h�U �OeCZ*_ui c-S�S�d X1c-Z&`�c^d h�S " � $ � $ � $ � � $ � " # " � $ � $ � � }(C&�w &�w � �Rh#zOd k�k�dS�c3`JU �Fdsh�U �OeCZ*_ui�c@S�S�d X1c-Z&`�c3dsh � � $ � " # " � $ � $ � � } |&�w &�w } � i�ds\�Q�]3U i�c@S�S�d X1c-Z&`�c3dsh% # " � $ � $ � $ � � $ � " # " � $ � $ � � &�{

&�w % � b�U � VJd \�Q�]^U eCc^`�bg�Rc-SJS"d X1c@Z�`Jc3d hTS � $ � $ � $ � � $ � " # " � $ � $ � � &}

� H L��� �]E�,���� � �B�?� ' ����9�1 ����/` ���

% w3{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � &�^% w � q tmk�]3c@X*Z�`Jc3d hTS � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � &�C% w } � b�URj U*k�V�U&S�U*h�`�Z�`Jc3d hud&[,Z��R\�Z&]IjCd \�`JU $ � $ � � $ � " # " � $ � $ � � %�{

%�w } w3{ � b�U �Rc-i�i�U*h � h�c3` &xk�Z X1U� " � $ � $ � $ � � $ � " # " � $ � $ � � %]&% w & &c3ta\�]-Z&`�c^d h�{ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � %(h

%�w &�w3{ �Rc^U*V�Z&V�X�b�c-X4Z�] D]3\�S�`�U*V��.h�Z�]^_�S�c-S $ � $ � � $ � " # " � $ � $ � � %a^%�w &�w � ! V�c^h�X1c^k�Z�] Ddstjk�d h�U*h `�S �.h�Z�]^_�S�c-S � $ � � $ � " # " � $ � $ � � h(h%�w &�w } ,Z&h�d h�c@X*Z�];�Rc@S�X1VJc3tjc^h�Z�h ` �Rh�Z�]^_�S�c-S $ � � $ � " # " � $ � $ � � ^D&%�w &�w & �Rc@S�X1\TS�S"c^d h $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^ %

% w % &c3ta\�]-Z&`�c^d h�� � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^`h%�w % w3{ � Z S �2�.U*`�Z&c3]-S. � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^(^%�w % w � � U&Z&V�h�c^h�la`�b�URjC\�]3UYd�[-^`C6eCc3`Jb�Z ! U4V�X1U*k�`�V�dsh " # " � $ � $ � � ^&|%�w % w } � $ \�]^`�c3]@Z*_U*V �RU*`�eFdsV � " � $ � $ � $ � � $ � " # " � $ � $ � � C(�%�w % w & �Rc@S�X1\TS�S"c^d h $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � C(h

� �����G�/`,�� ��.�,��Q� � � ������(/`,���5,3.'/ � � �/`���/ /

r

Page 15: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

h w3{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � C |h�w3{sw3{ Db�Z&k�`�U4VvP.WU*VJW�c^U*e! � " # " � $ � $ � $ � � $ � " # " � $ � $ � � | ~

h w � PRh�`�b�U ��Z&`�\�VJU�d�[ � r�X1U*k�`�c3dsh�S� # " � $ � $ � $ � � $ � " # " � $ � $ � � |(�h�w � w3{ � �Rds`�U6P.h2jC\�]^U&S � " # " � $ � $ � $ � � $ � " # " � $ � $ � � |]&h�w � w � &\�tjtuZ�VJ_ $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � |&%

h w } Dd h�h�U X1`�c^d h�c@S"`��(r�X�U*k�`�c^d h�S � " # " � $ � $ � $ � � $ � " # " � $ � $ � � |&%h�w } w3{ � b�Z&`cjC\�]^U $ Z&k�k�c^h�l?�RdU&SC`�b�U �RU4`"e,d V�� � U&Z&V�h�� " � $ � $ � � |a^h�w } w � � ! V�c^d V�cAWU4V�S"\TS��R_�hTZ�tjc@X �(r�X1U*k�`Jc3d hTS � $ � " # " � $ � $ � � {*~(�

h w & q tmk�]3c@X*Z�`Jc3d hTS � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*~ }h w % &c3ta\�]-Z&`�c^d hm} � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*~&%

h�w % w3{ q h `�V�d i \�X1`�c^d h � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*~&%h�w % w � � b�U y \�]3]^c3h�Z&V�c@Z � DbTZ�`�U4VYz�{*|s| }� � ZsS � � $ � " # " � $ � $ � � {*~(hh�w % w } � b�c@X�b �(r�X1U*k�`Jc3d hTS�� " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*~(Ch�w % w & � b�c@X�bgjC\�]3U � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { {D�h�w % w % &U Z�V�X�b�c^h�l g d VNZ��R\�Z�];jCd \�`JU ) �RlxZ�c3h � $ � " # " � $ � $ � � { { %

h w h �Rd \�Q�]3U��.c-S�S�d X1c-Z&`�c^d h�S " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D�a^h w ^ &c3ta\�]-Z&`�c^d h?& � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D�(C

h�w ^xw3{ $ U*`Jb�d i�ds]3d ls_ " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D�(Ch�w ^xw � � U&S�c3dsh�c3h�l $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D� |h�w ^xw } � U&S"`Jc3h�l $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*} ~h�w ^xw & jCU&S"\�]3`�S $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*} ~h�w ^xw % �Rc@S�X1\TS�S"c^d h $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*}�{

h w C Dd h�X1]^\�S"c^d h�S � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*}&%

� H ��� ������� � ��� � � ����9��5.D,���5. �0,��^xw3{ Dd h `�V�c^Q�\�`Jc3d hTS $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {*}a^^xw � � c3tjc^`�Z�`Jc3dsh�S � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {'&~^xw } Dd h�X1]^\�S"c^d h $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {'&��^xw & ! S�_�X�b�ds]3d lsc-X*Z&] q tjk�]3c@X*Z�`Jc3dsh�SDZ�h�i g \�`�\�VJU � d V�� � $ � " # " � $ � $ � � {'&}

^w &�w3{ � b�U j U4l \�]@Z�V�c^`�_�� � U&X1`� # " � $ � $ � $ � � $ � " # " � $ � $ � � {'&(&^w &�w � �(h�ls]3c-S�b ! ZsS"` � U*h�S�U&S " # " � $ � $ � $ � � $ � " # " � $ � $ � � {'&�h

r c

Page 16: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

^w &�w } ! V�dsh�d \�h�X1c3h�l��(h�ls]3c-S�b � U*r ` $ � $ � $ � � $ � " # " � $ � $ � � {'&�^^w &�w & �Rc@S�X1\TS�S"c^d h $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { % ~

6 ���� � ��]G���`� ����,� w3{Kj U*ls\�]-Z&V.Z�h�i �(r�X1U4k�`�c^d h � dsV�i�S* " � $ � $ � $ � � $ � " # " � $ � $ � � { % }� w �7j U*ls\�]-Z&V.Z�h�i �(r�X1U4k�`�c^d h � dsV�i�S* " � $ � $ � $ � � $ � " # " � $ � $ � � { %]&� w } �Rd h eFdsV�i�S $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { %&%

� �W��.'/�6 ��`� �� � �����G�/`,��� *-��<� ��,���� ��� �y w^{ q h `�VJd i�\�X1`Jc3dsh* � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { %a^y w � PRWU4V�W c3U*e � $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { %(C

�A9 �.D. ����� � �,

��,��9),����B�`��G�E � � ��

r�c^c

Page 17: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �� � ��� � � � �

� w3{ � b�U i�\�Z�] V�ds\�`�UYtjd i U*] d&[DV�U&Zsi�c3h�l�w $ � $ � $ � � $ � " # " � $ � $ � � { %

} w3{ � b�UYk�Z S�`R`JU*h�S"UYk�Z&`�`JU*V�h;Z S�S�d X1c-Z&`�dsV6zMjC\�tjU*]^b�Z�VJ`-� $ X�D]^U*]3]@Z�h�i o {*|�C(h���w ��{} w � � b�U'&U*c-i U*h�Q�U*VJl Z�h�i $ X�D]^U*]3]@Z�h�iuz�{4|(C |�Fh�U*`�eFd V��E[OdsVFtuZ&k�k�c^h�l tjdsh�d��

S"_ ]3]-Z&Q�c-X � h�l ]3c@S"b�eFd V�i�SF`�dmS"ds\�h�i�S�w $ � $ � $ � � $ � " # " � $ � $ � � �]&} w } � SJX�b�U4tuZ�`Jc-XYi�c-Z&l V�Z�t d�[C`Jb�U ! ]@Z�\�` Z&h�i $ X�D]3U*]^]-Z�hTiLz�{*|s| }��h�U*`�e,d V �

[Od V.tuZ�k�k�c3h�l tjd h�dxS"_ ]3]@Z�Q�c@X �(h�l ]^c-S"bue,d V�i�S `JdjS�d \�h�i�S1w% # " � $ � $ � � �(h

&�w3{ � S�\�tjtuZ&V�_6d&[,i�c-SJS"d X1c@Z�`Jc3d hTSK[Ods\�h�ijc3hu]3U S"c3dsh�U&iuX1dsh�h�U&X1`Jc3dsh�c-S�`Fh�U*`�e,d V ��S1wU&��

% w3{ � b�UYk=dxS"c^`�c3dshnd&[Dk�Z�`J`�U*VJh � c^h�Z6}���i�c3tjU4h�S"c^d h�Z&]Ab�c-i�i U*hj\�h�c^`.S"k�ZsX1Uw � %&%% w � � X�]3\�S�`�U*V.i�c@Z�lsV�Z�t d&[(`Jb�UYc3h `�U*VJh�Z�]AVJU*k�V�U S"U*h `�Z&`�c3dsh�SFd�[�V�U4l \�]@Z�VNZ�h�iuU*r �

X1U*k�`Jc3d haeFdsV�i�SDc3h ! ]-Z�\�`FZ&h�i $ X�D]^U*]3]@Z�h�i $ SFzJ{*| |s}��Dh�U4`"e,d V��6Z�`,`�b�UNX1dsh��X1]3\�S�c3dsh d&[D`�V�Z�c^h�c3h�l�w � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � h ~

% w } � X�]3\�S�`�U*V.i�c@Z�lsV�Z�t d&[(`Jb�UYc3h `�U*VJh�Z�]AVJU*k�V�U S"U*h `�Z&`�c3dsh�SFd�[�V�U4l \�]@Z�VNZ�h�iuU*r �X1U*k�`Jc3d haeFdsV�i�SDc3h ! ]-Z�\�`FZ&h�i $ X�D]^U*]3]@Z�h�i $ SFzJ{*| |s}��Dh�U4`"e,d V��6Z�`,`�b�UNX1dsh��X1]3\�S�c3dsh d&[D`�V�Z�c^h�c3h�l�w � b�U S"k�U*]^]3c3h�l6d�[�U&Z X�bueFd V�i c@SCS"b�d&eChAw � $ � $ � � h�{

% w & � X1]^\�S"`JU*V�i c-Z�lsV�Z&t d�[,`Jb�U c^h�`JU*V�h�Z&] VJU*k�VJU&S"U*h `�Z&`�c^d h�SCd�[,V�U4l \�]@Z�V*o�U*r�X1U*k��`�c3dshuZ�hTi h�d h eFdsV�i�SFc^h ! ]@Z�\�`KZ�h�i $ X�D]3U*]^]-Z�hTi $ SFzJ{*|s| }��,h�U*`�e,d V �aZ&`F`Jb�UX1d h�X�]3\�S�c3d h d&[�`JV�Z�c^h�c3h�l�w � d V�i�S b�Z*WUjQ�U*U*h ]@Z�Q�U*]3]^U&iLZsS V�U*ls\�]-Z&V�Sjz M ��oU*r�X�U*k�`�c^d h�S�z�� �DdsVCh�d h eFdsV�i�S z @ ��w $ � $ � $ � � $ � " # " � $ � $ � � h]&

% w % � X1]^\�S"`JU*V�i c-Z�lsV�Z&t d�[,`Jb�U c^h�`JU*V�h�Z&] VJU*k�VJU&S"U*h `�Z&`�c^d h�SCd�[,V�U4l \�]@Z�V*o�U*r�X1U*k��`�c3dshuZ�hTi h�d h eFdsV�i�SFc^h ! ]@Z�\�`KZ�h�i $ X�D]3U*]^]-Z�hTi $ SFzJ{*|s| }��,h�U*`�e,d V �aZ&`F`Jb�UX1d h�X�]3\�S�c3d hud&[D`�V�Z�c3h�c3h�l�w � b�U S"k�U*]3]^c3h�l6d&[DU&ZsX�bje,d V�i c-SCS�b�d&eChAw � $ � � h&%

r c3c^c

Page 18: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

% w h j U*ls\�]-Z&VuZ�hTi U*r�X1U*k�`Jc3dsh eFdsV�i�S�zpi�U*h�d `�U i V�U S"k�U&X1`Jc3WU*]^_:Q _ M Z�h�i � �k�]3ds`�`�U i d hj`Jb�U ��V�S�`F`�eFd X1dstjk�d h�U*h `�S(d&[�Zvk�VJc3h�X1c^k�Z�] X1dstjk�d h�U4h�`�S9Z&h�Z�] �_�S�c-SFd�[ ! ]@Z�\�`.Z&h�i $ X�D]3U*]^]-Z�hTi $ S.z�{*|s| }�Fh�U4`"e,d V�� w� $ � " # " � $ � $ � � ^`�

% w ^ j U*ls\�]-Z&VCZ&h�i U*r�X1U*k�`Jc3dsh6eFd V�i�S9k�]3d `J`�U&iad hj`Jb�U�TV�S"`,`�eFd X1d tmk=dsh�U*h `�S(d�[Znk�V�c^h�X1c3kTZ�],X1d tmk=dsh�U*h `�SYZ�hTZ�]3_�S"c@S d�[ ! ]-Z&\�`aZ�hTi $ X�D]3U*]^]-Z�hTi $ S zJ{*|s| }��h�U*`�eFdsV � w. � $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^&}

% w C � i�c-Z&l V�Z&t d&[ `Jb�UCS�c3tjk�]3U-C�� C�k=U4V�X1U*k�`�V�dsh \�S�U&i `�dN]3U&Z&V�h?jC\�tjU*]^b�Z�VJ` Z�h�i$ X�D]3U*]^]-Z&h�i $ S.z�{4|(C(h�WjC\�]3U�d&[�^`C6`�ZsS � w $ � $ � � $ � " # " � $ � $ � � ^&|

% w | � S�\�tjtuZ&V�_�d&[Y`�b�Uuk�Z&`�`JU*V�h d�[Ye,U*c3lsb�`�S c3h Z�h C�� C h�U4`"e,d V��L`�b�Z&` bTZ SQ=U4U*hu`�V�Z&c3h�U i dshn`Jb�URj \�]^UYd�[-^`C6`�Z S �j[Od VY{*~6U*k�d X�b�S1w " # " � $ � $ � � C ~

% w3{4~ � S�\�tjtuZ&V�_�d&[Y`�b�Uuk�Z&`�`JU*V�h d�[Ye,U*c3lsb�`�S c3h Z�h C�� C h�U4`"e,d V��L`�b�Z&` bTZ SQ=U4U*hu`�V�Z&c3h�U i dshn`Jb�URj \�]^UYd�[-^`C6`�Z S �j[Od VW�(�6U*k�d X�b�S1w " # " � $ � $ � � C�{

% w3{s{ �RhgC��3&�� CE[OU*U&i�[OdsV�eKZ�V�ijh�U4`"e,d V�� [Od VC]^U&Z�VJh�c3h�l6`Jb�URj \�]3UYd�[-^`C6`�ZsS � w � � C(�% w3{ � � ����i�c3tmU*h�S"c^d h�Z&]�V�U4h�i�c3`Jc3dsh d&[ `�b�Uc& �pi c3tjU*hTS"c3dsh�Z�]�b�c@i�i�U*ha\�h�c^`,S"k�ZsX1U�d�[

ZEta\�]3`Jc3]@Z _sU*V(h�U4`"e,d V�� w " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � C]&% w3{4} � b�U b�c@i�i�U*h�\�h�c^`�S�k�Z X1U6d&[D`�b�U ta\�]3`Jc3]-Z*_U�VFh�U4`"e,d V��uZ [O`JU*Vf&x~ U*k�d X�b�SRd�[

`�V�Z&c3h�c^h�l�w( � $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � C&%% w3{i& � b�UYb�c-i�i U*hu\�h�c3`.S�k�Z X�U6Z [O`JU*VWh ~6U*k�d X�b�S d&[(`JV�Z&c3h�c^h�l�w " # " � $ � $ � � C(h

h w3{ � b�U'# Dd VJV�U&X�` $ Z�k�k�c^h�l�$�d&[ �(h�l ]^c-S�b WU4V�Q�SF`Jd6`�b�U*c^VCk�Z S�`R`JU*h�S�U [OdsV�tuS�w | }h w � � b�U # j \�]3U $ Z�k�k�c3h�l�$6d�[ �(h�ls]3c@S"b WU*VJQ�S1ouZsS S"k�U&X1c(��U&i Q�_ `�b�U V�\�]^U

G ���� �"����� �"��T-���"��5ST�I&���1/M[&7 � �5X [�

# " � $ � $ � $ � � $ � " # " � $ � $ � � |]&h w } � b�URh \�taQ�U*VAd�[ c3h�X1dsV�VJU&X1` k�Z�`J`�U*VJh�S(WU*V�S�\�S `�V�Z�c^h�c3h�lN`�c3tmU�z%U4k=d X�b�S�� [Od V,Z

&�� ���J{R[OU*U&i�[OdsV�eCZ&V�i6h�U*`�eFdsV �6]^U&Z�VJh�c3h�lN`�b�UNS"c^tjk�]3U,`�V�Z�c3h�c3h�l S"U4`9c^h � Z�Q�]3U h�w3{ {*~s~h w & � b�U y \�]3]^c3h�Z&V�c-Z Z�h�i Db�Z�`JU*V z�{*|s| }�F[OU*U&i�[OdsV�eKZ�V�ijh�U4`"e,d V�� � $ � $ � � {*~(hh w % � k�]^d `(d&[ `Jb�UFh \�taQ�U*V d&[ kTZ�`�`JU*V�hTS tuZ�k�k=U ivc3hTX1d VJV�U&X1`J]3_�Q _ ZRV�U4k�]3c@X*Z�`Jc3d h

d�[D`Jb�U y \�]3]^c3h�Z&V�c-Z Z�h�i Db�Z�`JU*VYz�{4| |s}��Ch�U4`"e,d V��ji�\�V�c3h�l `JV�Z�c^h�c3h�l�w) $ � � { { {h w h � k�]3ds`vd&[C`Jb�U6h�\�t Q�U*V.d�[Kk�Z�`J`�U*VJh�S�tuZ�k�k�U&inc^h�X1dsV�V�U X1`�]^_ Q _�ZjVJU*k�]3c@X*Z��

`�c3dsh d�[N`�b�U y \�]^]3c3hTZ�V�c@ZuZ�h�i Db�Z&`�U*V�z�{4| | }� h�U*`�eFd V��Li \�V�c^h�l�`�V�Z�c3h�c3h�l�wDd h WU*V�lsU*h�X1U�eKZ SCV�U&ZsX�b�U&iuZ [O`�U4V�&|6U*k�d X�b�SCd�[�`�V�Z�c^h�c3h�l�w " � $ � $ � � { {'&

r c3W

Page 19: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

h w ^ � k�]3ds`vd&[C`Jb�U6h�\�t Q�U*V.d�[Kk�Z�`J`�U*VJh�S�tuZ�k�k�U&inc^h�X1dsV�V�U X1`�]^_ Q _�ZjVJU*k�]3c@X*Z��`�c3dsh d�[N`�b�U y \�]^]3c3hTZ�V�c@ZuZ�h�i Db�Z&`�U*V�z�{4| | }� h�U*`�eFd V��Li \�V�c^h�l�`�V�Z�c3h�c3h�l�wDd h WU*V�lsU*h�X1U�eKZ SCV�U&ZsX�b�U&iuZ [O`�U4VY{'&~6U*k�d X�b�S d&[D`�V�Z�c^h�c3h�l�w� " � $ � $ � � { {Dh

h w C D]3\�S�`�U*VDi c-Z�lsV�Z&t d�[ �`&~Yi�_ h�Z�tjc@X(V�U*ls\�]-Z&VCz # M $B� Z�h�ij{ h�U*r�X�U*k�`�c^d haz # � $B�k�Z�`J`�U*VJh�S1w � $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { {*|

h w | ! VJc3h�X�c3k�Z&] Dd tmk=dsh�U*h `�S �RhTZ�]3_�S"c@SRz ! �Y�Dd�[ Z V�U*k�]^c-X*Z&`�c^d hjd&[(`Jb�U y \�]3]^c �h�Z�VJc-ZaZ�h�i Db�Z�`JU*VYz�{4| | }�.S"c^t \�]-Z�`Jc3dshAw � $ � $ � � $ � " # " � $ � $ � � {D�(�

h w3{4~ ! VJc3h�X�c3k�Z&] Dd tmk=dsh�U*h `�S �RhTZ�]3_�S"c@SRz ! �Y�Dd�[ Z V�U*k�]^c-X*Z&`�c^d hjd&[(`Jb�U y \�]3]^c �h�Z�VJc-ZaZ�h�i Db�Z�`JU*VYz�{4| | }�.S"c^t \�]-Z�`Jc3dshAoeCc3`�bu]@Z�Q�U*]3]^U&i k�Z&`�`JU*V�h�S�w � $ � � {D�]&

h w3{s{ � ! VJc3h�X�c3k�Z&] Dd tjk�dsh�U*h `�S �RhTZ�]3_�S"c@S9z ! �v� d�[ Z�V�U*k�]^c-X*Z&`�c^d h d&[A`Jb�U y \�] �]3c3hTZ�V�c@Z6Z�h�i Db�Z�`JU*V z�{*|s| }�.S"c^t \�]@Z�`Jc3d h o�eCc^`�b;Z S�\�Q�S"U4`Rd&[(]@Z�Q�U*]3]^U&ijk�Z�` �`�U*VJh�SCS"b�d&eChAw � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � {D�&%

h w3{ � � X1d tjkTZ�V�c@S"dsh�d�[C`Jb�Umi�c-SJS"d X1c@Z�`�c^d h�SR[Ods\�h�i�c3h�`�eFdu]3U S"c3dsh�U&inU*r U*tjk�]-Z�V�Sd�[D`Jb�U y \�]3]^c3h�Z&V�c-Z Z�h�i Db�Z�`JU*VYz�{4| |s}��Ch�U4`"e,d V�� w � $ � " # " � $ � $ � � {*}�{

r W

Page 20: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

r W�c

Page 21: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �� � � � ��� �

% w3{ � b�U ��V�S"`F`JU*hmX1d tjk�dsh�U*h `�S(U*r `�V�ZsX1`�U iEQ _6`�b�U & ! &�& g � � P j k�V�dsl V�Z&t[OV�d t ZEVJU*k�]3c@X*Z�`Jc3dshjd�[D`Jb�U ! ]-Z�\�`.Z�h�i $ X�D]3U*]^]-Z&h�inz�{4| |s}��Ch�U4`"e,d V�� w � ^&~

% w � � b�URj \�]^UYd�[-^`C�w � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � ^`C

h w3{ � S�c3tjk�]3UC`�V�Z�c^h�c3h�laS�U*`C`�bTZ�`.X*Z&h Q�U i�U&SJX1V�c^Q�U&ijQ�_a`�eFdaZ�]^`�U*VJh�Z�`JUYS"U4`�SFd�[V�\�]^U&SCZ�h�iuU*r�X1U*k�`Jc3d hTS1w " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � |a^

h w � � r�Z�tmk�]3U&SDd�[Dc^h�X1dsV�V�U X1`FtuZ&k�k�c^h�lSFtuZsi�U�Q _uZ V�U4k�]3c@X*Z�`Jc3d hmd�[D`Jb�U y \�]3]^c �h�Z�VJc-ZaZ�h�i Db�Z�`JU*VYz�{4| | }�Ch�U*`�e,d V � Z�`Cc3`�SC}(h&`�bnU4k=d X�bnd&[(`JV�Z&c3h�c^h�l�w- � � { {*}

h w } � b�U ��V�S"`6S�U*WU*h X1d tmk=dsh�U*h `�S�U*r `�V�Z X1`JU&i Q _�`�b�U & ! &�& g � � P j k�V�d �l V�Z&t [OV�d t ZEVJU*k�]3c@X*Z�`Jc3dshjd�[�`�b�U y \�]^]3c^h�Z�VJc-Z Z&h�i*DbTZ�`�U4V zJ{*| |s}��,h�U*`�eFdsV � w&{D��{

h w & �Rd \�Q�]3U6i c-S�S�d X1c-Z&`�c^d h�S [Ods\�h�inc^h�Z6]3U&S�c3d h�U&i U*r U*tjk�]-Z�V,d�[D`Jb�U y \�]3]3c^h�Z�VJc-ZZ�h�i Db�Z�`JU*V zJ{*|s| }��,h�U*`�e,d V � o�d V�i�U*VJU&ijQ�_atuZ�lsh�c3`J\�i�U) " # " � $ � $ � � {*}]&

� w3{ � Z&V�Z�QTZ�h Z�hTi $ X�D]^U*]3]@Z�h�i $!S zJ{*|(C�^ �aS�U*`ad�[F& C VJU*l \�]@Z�VmZ�h�i U*r�X1U*k�`Jc3d heFd V�i�S1w " � $ � $ � $ � " # � " # " � $ � $ � $ � � $ � " # " � $ � $ � � { % }

� w � NR]^\�S"b �d�$ S�zJ{*|�^&|�� S"U*`Cd&[+&}6V�U*ls\�]-Z&V.Z�h�iuU*r�X1U*k�`Jc3d hmeFd V�i�S1w" � $ � $ � � { %]&� w } ! ]@Z�\�`NZ�hTi $ X�D]3U*]^]-Z�hTi $ S.z�{*|s| }�.S"U*`Cd&[I& C h�dsh�e,d V�i�S1w� " # " � $ � $ � � { %&%

r�W c3c

Page 22: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

r W c3c3c

Page 23: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

~

Page 24: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����� �

� �� � � � � � �� �

PRh�UR[OU&Z�`J\�V�UNd�[�X1dsl h�c^`�c3WU.k�VJd X1U&S�S�c3h�l6`Jb�Z�`CbTZ SFk�VJd�Wd �U&i6t \�X�b6V�U S"U&Z&V�X�bjd&WU*VD`�b�U�kTZ S"`[OU*e i�U X*Z i�U S c@S�`�b�Uab�\�tuZ�h#Z&Q�c3]^c3`�_n`Jd ]^U&Z�VJhLZ&h�i:VJU*k�V�U S"U*h `�� � ���4$-���O���B�� tuZ&k�k�c^h�lS )tuZ�k�k�c3h�lxSF`�b�Z&`.X*Z�h�Q=U i�U S�X1VJc3Q�U&ijQ�_ Z X1U4V�`�Z&c3hjVJU*l \�]-Z�VJc3`�_o Q�\�`NZ�]-S�d6k�U*V�tjc^`CZ6h�\�t Q�U*Vd�[�U*r�X�U*k�`�c^d h�SF`Jd6`�b�Z&`RVJU*l \�]-Z�VJc3`�_w

$ Z&h�_6[�Z X�U*`�SFd&[(VJU&Z S�d h�c^h�ljZ&h�i ]@Z�h�ls\�Z�lsUYc3h Wd ]3WU �\�Z S�c3V�U4l \�]@Z�VCtuZ&k�k�c3h�lS1w � X1d t��tjd h�U*r�Z&tjk�]^U z�Z�h�indsh�U6d�[K`�b�U `�eFdj`Jb�Z�`YeCc3]^]AQ�U \�S�U&i�X1dsh�S"c@S"`�U4h�`J]3_jc^h�`�b�c@SR`�b�U S"c-SC[Od Vc3]3]^\�S"`JV�Z&`�c3WUDk�\�V�k�dS�U&S���c-S(`�b�UCt Z�k�k�c^h�l�d&[ �(h�l ]^c-S�b WU*VJQ�S `Jdv`Jb�U*c^V(k�Z S�`F`JU*h�S"U S1w �.\�tuZ�hTSZ�V�U Z&Q�]3U `�dai�U*`JU&X1`.Z&h�i U*r k�]^d c3`C`Jb�UYV�U*ls\�]-Z&V�c^`"_ac3h�X1dstjtjdshjtuZ�k�k�c3h�lxS�zpS�\�X�b�ZsS /`�<9)� �/`��93�B � o � ��� � � ���R � o �B�`,�� � ��`, ���5 � ��eCb�c3]^U9U Z S"c^]3_�bTZ�h�i�]^c3h�l�o ZsS eFU4]3]po*`Jb�UFh \�tjU4V��d \�S(Z&h�i d�[O`JU*h c@i�c3dxS"_ h�X1V�Z�`�c@X9U*r�X1U*k�`�c3dsh�S(z E�� � �-E�� � � L��/ �-��/` � + � �R��. ��w��.h�d `Jb�U*VeFU*]^] � ��h�d&eCh#]3c^h�l \�c@S"`Jc-X6U*r�Z&tjk�]^U6d�[ Z �\�Z S�c3V�U4l \�]@Z�V6tuZ&k�k�c3h�l c@Sv`Jb�UjV�U Z i�c^h�l#Z�]^d \�iLd�[� h�l ]3c@S"bueFdsV�i�S�f(`�b�UYtuZ&k�k�c^h�l d&[�S"k�U*]3]^c3h�luzOd VJ`�b�dsl V�Z&k�b _=�D`JdaS"d \�h�i�SYz%k�b�dsh�d ]^d ls_=��w �(h��l ]3c@S"b6c@S h�d `�dsV�c^d \�S([Od VDc3`�S c3VJV�U*ls\�]-Z&V�c3`Jc3U&SAc3ha`�b�U.S"k�U*]3]^c3h�l �%`Jd���S"ds\�h�ijX1dsV�VJU&S"k�d hTi�U*h�X1Uxo�eCc^`�bZ�k�k�Z&V�U*h `�]^_'# V�U4l \�]@Z�V $&eFdsV�i�S�S"\�X�b6ZsS �� � � o � � � � Z�hTi .'/ � � � X1dU*r c-S�`�c3h�l�eCc3`Jb � Z&l V�Z&h�`# U*r�X1U*k�`Jc3dsh�S�$ S"\TX�b�Z S �9 � � � w_,Z&V�c3ds\�SFU*r k�]-Z&h�Z�`Jc3dsh�S9b�Z*WU�Q�U*U4hjk�V�dsk�dS"U i `�daZsX*X1ds\�h�`D[Od VCb�d&e `�b�UNb�\�t Z�huX1dsl h�c �

`�c3WU S"_�S"`�U4t c@SCZ�Q�]^U `Jd ]^U&Z�VJhnZ&h�inc3tmk�]3U*taU*h` �\�Z S�c3V�U4l \�]@Z�V.tuZ�k�k�c3h�lxS1w � b�U6i�dstjc3hTZ�h `k�Z�V�Z i�c^l t�od&WU*VD`�b�U.k�ZsS"`F[OU*e i�U&X*Zsi�U&S1o b�Z SDQ�U*U*hj`Jb�U � �s56/ G �B$- k�Z&V�Zsi�c3lst zOUw l�w3o �RU*e,U*]3]� &c3tmd hAo�{4|(h {���w � b�UYS�_�taQ�d ]^c-X9kTZ�V�Zsi�c3lst k�dxS"c3`�S9`Jb�Z�`,b�\�t Z�h�S(`�VJU&Z�`,X1dsl h�c^`�c^WUCc3`�U4tuS1oS"\�X�b�Z SRe,d V�i�S1o Z S � � 56/ G � � o�Z&h�i�Z�k�k�]3_jlsU*h�U*V�Z�] �1��3��� `JdjS�\�X�b�S"_ taQ=ds]-SD`�daU � U&X1`.tuZ�k��

{

Page 25: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ������������� �������������������������

k�c3h�lxSRS�\�X�bnZsS `Jb�dS�U6i�U S�X1VJc3Q�U&ijZ&Q=d&WUw g d VCU*r�Z�tmk�]3Uob \�tuZ&h�SFeFds\�]-ij]3U Z�V�h o�S"`�dsV�U Z�hTiZ�k�k�]^_j`�b�U [Ods]3]^d�eCc^h�l6l U4h�U*V�Z&]AV�\�]^UR[Od V.tuZ&k�k�c3h�l6V�U*ls\�]-Z&VCWU*V�Q�SD`�da`�b�U4c3VCk�ZsS"`.`�U*h�S�Uf

k�Z S�` `JU*h�S"Uxz%WU*VJQ ��� S"`�U4t�z%WU*VJQ �� #Hi $

� b�c-SuS"_ t Q�ds]3c-Xso �����^� ��/����&�J� Z�k�k�V�dxZ X�b b�ZsSjQ=U4U*h \�S"U i eCc^`�b S"\TX*X1U&SJS `Jd U*r�k�]3c-X4Z�`�UZ�]3]�tuZ�h�h�U*VRd&[C]^c3h�ls\�c-S�`�c-X Z�h�i#X1dsl h�c^`�c3WU k�b�U*h�d tjU*hTZ�o c^h�X1]3\Ti�c3h�lmV�U&Zsi�c3h�l�Z&]3d \Ti z Dd ]3` �b�U&Z�VJ`*o D\�VJ`�c@S1o �C` � c3hTS1o�� ��Z�]^]3U*V4oF{*|s| }��oDk�Z S�`��O`�U*h�S�Ujl U4h�U*V�Z&`�c^d h z ! c3h �U*V*oD{*|s|�{&��oD`�b�US"_ ]3]-Z&Q�c �=X*Z�`Jc3d hud&[ �(h�ls]3c@S"bne,d V�i�S z &xU*c-i�U4h�Q�U*VJl�oA{*|s|(��.Z�h�i�X4Z�`�U4l d VJ_u]3U&Z&V�h�c^h�lnz &b�Z&h ��S� &`*wL= dsb�hAo�{*|s|]&���w � b�UYS"_ t Q�ds]3c-S�`�S"$�lsU*h�U*V�Z�]�W�c^U*e c-S(`�bTZ�`F`Jb�U.l dZ&]�d�[�Z�k�V�dsk�U*VF`Jb�U*d VJ_c-S�S�c3tjk�]^_ `Jdu\�h�X1d&WU*VNZ ������4$-5 G ��$ G �x�Y�&��� G 2E�1��3��� `�d�i�U S�X1VJc3Q�U `Jb�UaX1d lsh�c3`Jc3WUYk�VJd X1U&S�Sc3h ��\�U&S"`Jc3d h#z ! c^h �U*V � ! V�c^h�X1Uo {*|(C�C���wN.c^WU*h `Jb�UNZ S�S�\�tjk�`Jc3dsh `Jb�Z�` ���O���B�� c3`�U4tuS Z&V�U�bTZ�h�i�]^U&i Q _6`�b�UNZ�k�k�]3c@X*Z�`Jc3d hmd�[AlsU*h��

U*V�Z&]�V�\�]^U&S1o`Jb�UCk�V�dsQ�]3U4t h�Z�`J\�V�Z&]3]3_0Z�VJc-S"U S d&[Ab�d&e `�d6ZsX*X1ds\�h�` [Od VD`�b�UNX1dsV�V�U X1`(k�VJd X1U&S�S�c3h�ld�[Cc^`�U*t SR`�dueCb�c@X�b#h�duk�Z�V�S"c^tjd h�c^d \�SYS�U*`Yd�[.V�\�]3U&S�eFds\�]-i#X1dsV�V�U X1`�]^_�Z�k�k�]3_w q h�i�U*U&i o c3hS"d tmU�Z&V�U&ZsS9d�[ ]@Z�h�ls\�Z�lsUYk�V�d X1U S�S"c^h�l�o c3`,c-S(eCc-i�U4]3_6Q�U*]3c^U*WU&i `Jb�Z�` � G S"U*`,d�[ lsU*h�U*V�Z�]�V�\�]^U&SX*Z�huk�dSJS"c3Q�]3_jU*r c-S�`D`�b�Z&`Cb�Z�h�i ]3U&SFU*WU4V�_6]3U4r�c@X*Z�]�c3`JU*t X1dsV�V�U X1`�]^_nzOUw l�w3oc3hj`Jb�UYk�V�dsh�\�h�X1c-Z��`�c3dshud�[ �(h�ls]3c-S�bueFd V�i�S1f �R]^]3U*hAo �R\�h�h�c-X�\�`�`4o�� P�]@Z�`�`4oA{*|�Ca^�� Dd ]^`�b�U Z�V�`4oA{*|�^`C���w

� b�c-SFk�VJd Q�]^U*t c@S9`�_ k�c-X*Z&]3]^_aS"d ]^WU&i Q _ k�dxS"`�\�]-Z�`Jc3h�l6`Jb�Z�`Cc^`�U*t S `Jb�Z�`.X4Z�h�h�ds`CQ�UvbTZ�h��i�]3U&iaQ�_uZ6l c^WU*huS�U*`Cd�[�V�\�]^U&S ) ���s1�p����$ G � c^`�U*tuS )mZ�VJU S�`�dsV�U&iuc3h�S"dstjU � c3h�i d&[Dc3h `�U4V�h�Z&]]3dd&� \�k�`�Z�Q�]^Uw �DZ X�bnc^h�i�c3W c-i \�Z�]AtuZ&k�k�c^h�l [OV�dst Z&h�U*r�X1U*k�`Jc3d hmc3`�U4t `�djc^`�SCc3tuZ&l U�ta\�S�`Q=U 5 ��5 G �1$��&�J� o c^h#X1d h `�V�Z S�`v`Jdu`�b�U6lsU*h�U*V�Z�](VJ\�]3U&S.eCb�c-X�b#Z�VJU $-�����1�J� W�c@Z U*r k�dS"\�V�Ua`�dt \�]^`�c^k�]3U.S�c3tjc^]-Z�VDtuZ&k�k�c^h�lS�w

� b�c-S [OdsV�ta\�]-Z&`�c^d h c3tjk�]^c3U&SmZ Q�ZsS"c-X i�c-S�`�c3hTX1`�c^d h Q�U*`�eFU4U*h VJU*l \�]-Z�V;Z�h�i U*r�X1U*k�`�c3dshc3`�U4tuS1oQ�U&X*Z&\�S"UY`�b�U*_uZ�VJUYb�Z�h�i ]3U&ijQ _ `�eFdaS�U*k�Z&V�Z�`JU tjU X�b�Z&h�c-S�tuS c^h `Jb�U X1d lsh�c3`Jc3WUNS"_�S �`�U*t�f.V�\�]^UaZ�k�k�]3c-X4Z�`�c^d h Z�h�i#`�Z�Q�]3U �O]3dd ��\�k w � b�c@S `Jb�U*dsV�_ )�eCb�c-X�b X*Z�h#Q�U VJU*lZ&V�i�U&i#Z SZ�hnU4]-Z�Q�dsV�Z�`Jc3dsh�d�[D`Jb�UYV�\�]^U �%QTZ S"U inZ�k�k�V�dxZ X�b�`�b�Z&`�Z&]3]3d&e.SCc3`C`JdjZsX*X1d \�h�`C[Od V.U*r�X1U*k�`Jc3d hTS)ab�Z SFQ�U*U*h i�\�Q�Q�U&ij`�b�U �1��3� � � G ��� `Jb�U*dsV�_aQ�_ ! c3h �U*V.zJ{*| | {���o=Q�\�`Fc3`,c-SDk�V�dsQ�Z�Q�]^_jQ�U*`�`JU*V��h�d&eCh�Z SC`�b�U �� � � � G ���� `Jb�U*dsV�_ �vz y Z�V�dshg� &`�V�Z e.S�d hAoA{4|a^0h � Dds]3`�b�U&Z�VJ`*oA{*|�^`C��w

!#"%$'&'(*)+$-,/.�0'1 24365�(/798;:<$'=>2?$-2@&'ACBED%F;36, &'G<F9$'2H$'=>2@GI&-.KJ�G<79,/.L3M1919,/(/2@0N$-GO&-243ID�(/798�36,/G<F;DP:<Q9F9$R$'=92H8I2�792@&S3M,(*D�2T3VUW367 D�$'=>20'1 24)+(YXK)H$-2@&'A�ZR=;360[AV(/8I&S3M$'24D�$-G�A\3M7].�GI$-=92@&�3M&'243M0�G6^N)+GI8<79(/$'(/_I2`19&'G9)+2�0'0'(/798�360[aR2@,/,cb

Page 26: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

}

� b�ULi�\TZ�]YV�ds\�`�U�`Jb�U*d VJ_ b�Z SjtjdxS"`uS�\�X*X1U S�S [O\�]3]3_ Q�U*U*h Z�k�k�]3c^U&i `�d tjd i�U4]3]3c^h�l#`�b�UV�U&Zsi�c3h�l#Z&]3ds\�iLd�[ �(h�l ]^c-S�b `JU*r `jz Dds]3`Jb�U&Z�VJ`6U*`6Z&]pw^oF{*|s| }��w q ` b�ZsS Q�U*U*h S"b�d&eCh `�d�Q�UZ�Q�]^U `�d Z X*X1ds\�h `R[Od V.U*tjk�c^V�c@X*Z�] V�U&Zsi�c3h�lmk�b�U*h�dstjU*h�Z6S�\�X�b#Z SRk�VJd h \�h�X1c@Z�`Jc3d h�]@Z�`JU*h�X1c^U&S1oeFd V�i VJU&X1dsl h�c^`�c3dsh�]-Z&`�U*h�X�c3U&S�o `�V�Z�\�tuZ��%c^h�i�\�X�U&inV�U&Zsi�c3h�ljc3tjkTZ�c3VJtjU*h `�S.zpS"\TX�b Z S �4� �@24�1�Z�h�i ��� G � G � G �$-�� � i�_�S"]3U4r�c@Z���o i�U*WU*]^d k�tjU4h�`�Z�] i�_�S"]^U*r�c@Z S�oAZ�h�i#i�c@S�S"d X�c-Z�`Jc3dsh�S zO`�b�U&S�U6eCc3]^]Q=U i�c@S�X1\TS�S"U i c^hutjd VJUYi�U*`�Z�c3]Ac^h Db�Z�k�`JU*VW����w

� b�Uai�\�Z�]�V�d \�`�U6`�b�U*d VJ_neCZsS�`�b�U0i�d tjc^h�Z�h `NZ X*X1ds\�h `�c3h�`Jb�Uj{4|a^&~ $ S Z�h�iL{4|(C ~ $ S�[Od V`�b�VJU*UCtuZ���dsV VJU&Z S�d h�S�f(c3`�S�Z�Q�c^]3c3`�_Y`�d ZsX*X1d \�h�` [OdsV,Z eCc@i�UCV�Z&h�l U.d�[ b�\�tuZ�h0i�Z�`�Z�o�`Jb�UC]-ZsX �d�[�Z X�V�U&i�c^Q�]3Uxo eFdsV � c3h�l0Z�]3`JU*V�hTZ�`�c^WUoZ&h�ijc3`�S(c^h�`J\�c3`Jc3WU.Z�k�k=U Z�]pw��.d�e U4]-S"Uxo�dsh�UYX1dstjtjU*h��`�Z�`Jd V.ZsS �U&inz j dxS"U*h Q�U*V�l�oA{*|�C(C���o=e,d \�]@i c3`,Q�Uvk�dxS�S"c^Q�]3UN`�d6k�VJd h�ds\�h�X1UYh�dsh�e,d V�i�S � zpS"\TX�bZ S �� �B/ Z�h�i � L��� ��cB[.h�d `aW c-ZnZ�S�_�S�`�U*t d�[Nl U4h�U*V�Z&]CV�\�]^U&S1oDZ&h�iLb�d&e U4]-S"U X1d \�]@iLd h�Uk�V�dsh�d \�hTX1U6U*r�X1U*k�`Jc3d hTS�S"\�X�b�ZsS �>���]E/ Z&h�i ���B9���5L9 o=cB[Dh�d `YW c-Z6eFdsV�i ��S"k�U&X1c(� X tjU*tmd��V�c � Z�`�c^d h��

� b�U�S�\�X*X1U&SJS(d�[A`Jb�U.i�\�Z&]�V�d \�`�U.`�b�U*dsV�_6c^h U*r k�]^c-X*Z&`�c3h�lR`Jb�URVJU&Z i c3h�l �pZ&]3d \Ti d�[ � h�l ]3c@S"b`�U*r `*oZ&h�i6`�b�U.]-ZsX �Yd�[ ZYX1V�U&i c3Q�]^UCZ�]^`�U*VJh�Z�`Jc3WUo&]3U i d h�U.d�[ c3`�S(tuZ���d V k�V�dsk=dsh�U*h `�SD`�dYtuZ"�U`�b�UKS"`�VJd h�l X1]@Z�c^t `Jb�Z�` � G tjd i�U*]�X1d \�]-ivc^tjk�]^U*t U4h�` S � c3]3]^U&i�V�U&Zsi�c3h�l�c [�c^`(i c-i h�ds`DX1d h `�Z&c3hZ i�\TZ�] V�d \�`�Uaz Dds]3`�b�U&Z�VJ`*o {*| |`&Z��w � b�Z�`.c-S�o=c^`CeCZsSRX1]@Z�c^tjU&i6`�b�Z&`Rh�ds`Rdsh�]3_�i�dab \�tuZ�hTSb�Z*WU Z&hnc^h�`JU*V�h�Z&] i�\�Z&] VJd \�`JUo=Q�\�`R`Jb�Z�` ���� S"_�S"`JU*t X*Z&k�Z�Q�]^U d&[,S � c3]^]3U&i VJU&Z i c3h�laeFds\�]-ih�U&X1U&SJS�Z&V�c3]^_jZ&]-S�d c^h�X1d VJk�d V�Z&`�U0Z6i�\�Z�] V�ds\�`�U Z&V�X�b�c3`JU&X1`�\�V�Uw

q h `�b�U#k�ZsS"`n`JU*h _U&Z�V�S1o�b�d&eFU4WU*V*o.Z�h Z�]3`JU*V�hTZ�`�c^WU#Z X*X�d \�h `nd&[6b�d&e �\�Z S�c3V�U4l \�]@Z�VtuZ�k�k�c3h�lxSjZ�VJU:c^tjk�]3U4t U*h`JU&iLb�Z SjlxZ�c3h�U&i c^h S�`�VJU*h�l `Jb Z&h�i c3h `�U*VJU&S"`4w � b�c-SmZ X*X1ds\�h `*oZ X*X1dsV�i�c^h�l�`�d#c3`�S6Z i�Wd X4Z�`�U S1oFU&SJX�b�U*e.S Z&h�_Lh�d `�c^d h d�[YVJ\�]3U&S Z�h�i ]3dd � �O\�k `�Z�Q�]^U&S1o,Z�hTic3h�S�`�U&Zsi k�VJd k�dS�U&S Z&hLc3h `�U4l V�Z&`�U&i o c^h�i�c^W�c@S"c3Q�]3UYtjU&X�b�Z�h�c-S"t [OdsVvbTZ�h�i�]^c3h�l�Q�d `�b V�U*ls\�]-Z&V�SZ�h�ijU*r�X1U*k�`Jc3dsh�S1w $ d i�U*]-SDQ�Z S�U&ijc3ha`�b�c@SFk�Z�V�Z i�c^l t b�Z*WU�Q�U*U*huZ&k�k�]^c3U&i oeCc^`�bjc^h�X1V�U Z S"c^h�li�U*l VJU*U&S6d�[0S"\TX*X1U&SJS1oF`JdL`�b�U�]3U&Z&V�h�c^h�l Z�h�i c^tjk�]3U4t U*h`�Z�`Jc3d h d�[0X1d tmk�]3U*r �\�Z S�c3V�U4l \�]@Z�VtuZ�k�k�c3h�lxSCS"\�X�b�Z SC`�b�dxS"U i�U&SJX1V�c^Q=U i Z&Q�d�WUxw

� b�UvkTZ�V�Zsi�c3lst c3h �\�U&S�`�c3dshjc-SF`Jb�U G ���=�J1��$ G ��$ ��� k�Z&V�Z i c3l t;o�Z�hTi c^`*o�Z�h�iuc3`�S,Z�Q�c^]3c^`"_`�d�]^U&Z�VJh6Z�hTi c3tjk�]^U*taU1h ` ��\�ZsS"c^V�U*ls\�]-Z&V(tuZ�k�k�c3h�lxS1o&eCc3]^]Q=UC`Jb�UFt Z�c3h�[Od X1\TS d�[�`Jb�c-S `�b�U&S�c-S�wq h6`Jb�U.X1dsh�h�U&X1`Jc3dsh�c-S�`(k�Z�V�Z i�c^l t�osh�U*`�eFdsV ��S d�[ S"c3tmk�]3UDk�VJd X1U&S�S�c3h�lY\�h�c3`�S�Z�V�U.`�V�Z�c^h�U&i Q _6Z

�4"%2@2H$'=92�� , G<0'0+36&'.�2�7]$-&'.�b

Page 27: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

& ������������� �������������������������

k�V�d X1U S�S9d&[(b�c3]3]TX1]3c^t Q�c^h�l�osX1VJU&i�c3`,ZsS�S"c^l h�tmU*h�`4oZ�hTi e,U*c3lsb�`,Zsi���\�S"`JtjU*h `(`�d6VJU&i�\�X�URU*VJV�dsV�Sc3h ZntuZ&k�k�c^h�lj[OV�d t Z�S"U*` d�[ i�d tuZ&c3h#c3`JU*tuS�`�d#Z�S"U*`6d&[.V�Z�h�l Uuc3`JU*tuS1w � b�UutuZ&k�k�U&ic3`�U4tuSDX*Z�h�Q=UazOU*h�X1d i�U i=�Dh�\�t Q�U*V�S1o�kTZ�`�`JU*V�hTS1o�d VC]^U*r c-X*Z&] U*h `�c^`�c3U S1w

Ddsh�h�U&X�`�c3dsh�c-S�`Ch�U*`�eFdsV ��S9k�VJU&S"U4h�`KZ V�Z i c-X*Z&]AZ�]^`�U*VJh�Z�`Jc3WU.`�d6`Jb�UYS"_ taQ=ds]3c@XRZ&k�k�V�dxZ X�bAoc3` c@S6X1]-Z&c3tjU iLzMjC\�tjU*]^b�Z�VJ`�� $ X�D]3U4]3]-Z&h�i o,{*|(C�h ��&U*c-i U*h�Q�U*VJl � $ X�D]3U*]^]-Z&h�i oF{4|(Cs|���oQ=U X*Z�\�S�U6`�b�U4_nZ&V�U0Z�Q�]^U6`�dac3tjk�]^U*tjU�h�`�)�Z�hTin]3U&Z&V�h ) ��\�ZsS"c^V�U*ls\�]-Z&V�tuZ�k�k�c3h�lxS eCc^`�b�ds\�`Z�h _6Z�k�k�Z�VJU*h�`Dh�U4U&iv`JdvU4h�X1d i�U.S�_�taQ�d ]-S�o V�\�]3U&S�o d V(]^dd&� �%\�k `�Z�Q�]^U&S(c3h6`�b�UCh�U*`�eFdsV � Z�V�X�b�c �`�U&X1`J\�V�Uxw � b�U.X1d tjk�]3U*`JU9t Z�k�k�c^h�l�c@S \�h�cB[Od V�tm]3_�c^tjk�]3U4t U*h `�U4i�c3h `�b�U.S�U*`Dd�[ 89��$ ��� �-� `Jb�Z�``�b�UYh�U*`�e,d V �mX1dsh�S"`JV�\�X1`�SRi \�V�c^h�l ]^U&Z�VJh�c3h�l�o�`Jb�V�ds\�l b�U*r k=dxS"\�VJU `Jd6tuZ�k�k�c3h�l6U*r�Z�tmk�]3U&S�w

! VJU&S"U*h `�]^_o�`Jb�U t Z���d V,V�U&S�U&Z�V�X�b �\�U&S"`Jc3dshn`�bTZ�`NS"U*U*t S9`�daQ�U6Z&Q�S"dsV�Q�c^h�ljtjdxS"`Cd�[ `�b�Uc3h `�U*VJU&S"` )mZ�hTi U � d VJ` )ac3hj`Jb�U ��U*]@i d�[ ��\TZ S"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxS1o c-S9`Jb�Z�`Cd&[Di U*`�U*VJtjc3h�c3h�l8 ��$-�� d&[ `�b�UC`�eFdN`�b�U*dsV�U*`Jc-X*Z&]�Z&k�k�VJdZ X�b�U&S(ds\�`�]^c3h�U&i6Z&Q�d�WUCk�V�d&W�c@i�U&S `Jb�U.S"\�k=U4V�c3dsV(tjd i�U4]d�[�b�\�t Z�h ��\TZ S"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxS1w

� b�U k�VJd l VJU&S�S.c3hAo Z�h�in`Jb�U6S�b�U*U*V.Wd ]^\�tjU.d�[Jo `Jb�U VJU&S"U Z�V�X�buV�U*k�dsV�`�U inc3hu`�b�c@SRZ&V�U&Zac-S`�U&S�`�c3tmd h _R`JdR`Jb�UDk=U4V�X1U*c^WU&iRc^tjk�d V�`�Z�h�X�U9d&[�`�b�c-S ��\�U S"`�c^d hAw g V�dst S"c3tmk�]3c@S"`�c@X Q�U*lsc3h�h�c3h�lxS1oc3tjk�]^U*taU*h`�U&iaX1dsh�h�U&X1`Jc3dsh�c-S�`Ctjd i�U*]@S9d�[ k�Z S�`��O`�U*h�S�UaZ�h�iuV�U&Zsi�c3h�laZ�]3ds\�inb�Z*WUYZsi�WsZ�h�X1U iV�Z�k�c-i�]^_ c^h#S"dsk�b�c-S�`�c@X*Z�`Jc3d h#Z&h�i�k=U4V"[Od VJtuZ�hTX1Uo�Q=ds`�b#c3h�`�b�U*c^VYZ�Q�c3]3c^`�_j`�duc3tmk�]3U*taU�h�`,`�b�U]3U*r c-X*Z&] t Z�k�k�c^h�lS�o Z�h�i�`�d�V�U*k�VJd i�\�X1Uab \�tuZ�h�kTS"_�X�b�ds]3dsl c-X4Z�](k�U*V�[Od V�t Z�h�X1Uai�Z�`�ZueCb�c3]^Ui�d c^h�l S"d z%Uxw l�w^o���Z&\�l b�U4V�`�_ � &U*c-i U*h�Q�U*VJl�o�{4| |�� � $ Z X � b�c3h�h�U*_�� � U*c^h�Q�ZsX�b o�{*|s|�{��! ]@Z�\�`g� $ X�D]3U*]^]-Z�hTi o�{*|s| } � ! ]@Z�\�`4o $ X�D]^U*]3]@Z�h�i o &U4c-i�U*h Q�U*V�l�oW� ! Z�`J`�U*V�S"dshAo6{*|s|]&��j \�tmU*]3b�Z&V�`W� $ X�D]3U4]3]-Z&h�i o {*|�C(h ��&U*c@i�U*h Q=U4V�l�� $ X�D]^U*]3]@Z�h�i o {4|(C |��w q h�VJU&S"k�d hTS"Ua`�d`�b�c@S9X�b�Z&]3]3U4h�l Uoxi�\�Z�] V�ds\�`�U�`Jb�U*dsV�c-S�`�S(b�Z*WUC[OU*]3`,X1dstjk�U*]3]^U&iv`Jd6Z�VJl \�U.[Od VF`Jb�U �=�J1�����4$3� � d�[V�\�]^U&S Z&h�i U*r�X1U*k�`Jc3dsh�S c3h U*r�k�]-Z�c^h�c3h�lRb \�tuZ&hvk�U*V�[Od VJtuZ�h�X�URz ! c3h �U*V4o�{4| | {���o Z&h�i b�Z*WU,Z�k��k�Z�VJU*h�`J]3_6[OU*]3`,S�\��uX�c3U*h `�]^_aX�b�Z&]3]^U*h�l U iE`JdaX1d h�S�`�VJ\�X1`*o�ZsSFeFU*]^]po X1dstjk�U*`�c^h�l G 5R� ����� �p$ G ��� �i�\�Z�]�V�d \�`�UCtjd i�U4]-SAd�[ V�U&Zsi�c3h�l Z&]3ds\�i6Z�h�i6k�ZsS"`D`�U*hTS"UFlsU*h�U*V�Z�`Jc3d h�z%Uxw l�w^o Dds]3`Jb�U&Z�VJ`(U*`DZ&]pw^o{*| |s} �-� c3h�l�oD{*| |`&Z��w &c3lsh�c � X4Z�h `vtmd i�c � X4Z�`�c^d h�S.`�d�S�k�U&X1c �=X6i�\�Z�],V�ds\�`�Ua`�b�U4d V�c^U&S�b�Z*WUQ=U4U*hLZuV�U&X�U*h�`NV�U&S�\�]3`Yd�[.`Jb�c-S�h�U4eC]3_�c3h `�VJd i�\�X1U i VJc3l ds\�VjzOUw l�w3o Dd ]^`�b�U Z�V�`YU*`0Z�]�w3oD{*|s| } �! c^h �U*V4o {*|s|�{&��w

� b�U6X1\�VJV�U*h `Ci c3V�U X1`�c^d hud�[�eFdsV �uc3hu`�b�c-S.Z�V�U Z )uZaX1d h `�c^h�\TZ�] S"U Z�V�X�bj[Od V ���B�/ G �J� �p$ G ���d�[ `�b�URVJU&S"k�U&X1`Jc3WUCtjd i U*]-S `Jd c^tjk�V�d&WU,k�V�U&i c-X1`Jc3WUFk�U*V�[Od VJtuZ�h�X�U )6V�U ��U&X1`�S9Z&hjc3tmk=dsV�`�Z�h `

Page 28: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

%Z S�S�\�tjk�`Jc3dsh `Jb�Z�`,c-S9c^tjk�]^c-X1cB`�]^_�b�U*]@iEc^h Q�ds`�b�X*Z�tmk�S��h�Z&tjU*]3_xo�`Jb�Z�`,`�b�U�`�e,d Z&k�k�VJdZ X�b�U&S���� [O\�h�i�Z�tmU*h�`�Z�]^]3_ i�c � U*V�U*h `*oKZ�h�i `Jb�Z�`j`Jb�U�V�U S"U&Z&V�X�b �\�U&S"`Jc3dsh d�[mz%`Jb�U � tjd tjU4h�` c-Si�U*`�U4V�tjc^h�c3h�lYeCb�c@X�bmc-SF`�b�UvQ�U*`J`�U*VCtmd i�U*] d&[Db \�tuZ�h X1d lsh�c3`Jc3d h wjCU&X1U4h�`J]3_o b�d&eFU*WU*V4o�k�b�c3]3dxS"dsk�b�c-X4Z�] d Q���U&X1`Jc3dsh�SFb�Z*WU Q�U*U*huV�Z�c-S�U&i VJU*lZ&V�i�c^h�lj`Jb�U WU �

V�Z X�c3`�_Ld�[ `Jb�c-SaZ SJS"\�tjk�`�c3dsh � z $ X�D]^dS �U4_oR{4| | {��'&]3U � Z"� oR{4| |]& ��w &k�U&X�c � X*Z&]3]^_o(c3`ab�Z SQ=U4U*h �\�U&S"`Jc3dsh�U&i:eCb�U4`�b�U*V `�b�Um`"e,d�tjd i�U*]@SYZ�V�UuQ�U*c^h�l�X1dstjk�Z&V�U&iLZ&` `Jb�UuS�Z&tjU �3��I���� �d�[0Z�h�Z&]3_�S"c@S��&w ,Z&h dsh�U#Z SJS"\�tjU�`Jb�Z�`u`Jb�U ����� �4$-�� � S�c3h�ls]3U�V�ds\�`�U�d&[aZ X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��Z�]@S"d�X1d VJV�U&S�k�d h�i�S�`JdnZ 24������p$ G ��� � S"c3h�l ]3U6VJd \�`JU � �C`�Z&hLZ&k�k�V�dsk�V�c@Z�`JU ]^U*WU*]Ad�[Z�h�Z&]3_�S"c-S�o�tjc3lsb�`Ddsh�U h�ds` ��h�i�Zv[O\�h�X1`Jc3d hTZ�] i�\�Z&] VJd \�`JU Z�V�X�b�c^`�U&X1`J\�V�UNU*h�S�X�d h�X1U i eCc3`Jb�c3h`�b�U X1dstjk�]3U4r�c^`"_ d�[ Z X�d h�h�U X1`�c^d h�c@S"`Ch�U*`�e,d V � �

� b�U&S"U6dsQ���U&X1`�c^d h�S.b�Z*WUoAZ S�_U*`4o=k�V�d&Wd&�U&in]^c3`J`�]3UYVJU&S"k�d hTS"U6[OV�d t `�b�UmX1dsh�h�U&X1`Jc3dsh�c-S�`X1d tjta\�h�c^`p_�z%Q�\�` S�U*U ! ]-Z�\�`F� $ X�D]^U*]3]@Z�h�i oA{4| |s}���w � b�UaV�U Z S"dsh [OdsV�`�b�c-SYS"c^]3U*h�X�Uvt Z _S"c3tmk�]3_jQ�U6k�V�Z�lstuZ�`Jc-X���`�b�U4V�UaZ�VJUoAZsSR_U*`*o�[OU*e l U4h�U*V�Z&](`�U X�b�h�c!�\�U&SCZ*WsZ�c3]@Z�Q�]^Uv[OdsVvc^h�`JU*V��k�V�U*`Jc3h�lY`Jb�U [O\�h�X1`�c^d h�Z&] Z�V�X�b�c^`�U&X1`J\�V�U,d�[�Z�`�V�Z�c^h�U&iaX1d h�h�U&X1`�c^d h�c@S"`Dh�U*`�e,d V � w q h�i U*U&i o c^`Dc-SV�U&X1dsl h�c �*U&i�`�bTZ�`(`Jb�c-S k�V�d Q�]3U*t ) b�d&e `Jd�U*]^\�X1c-i�Z�`�UD`Jb�UFc^h�`JU*V�h�Z&] [O\�h�X1`Jc3dsh�Z�]^c3`�_�d�[ `JV�Z�c^h�U&ih�U*`�eFdsV ��S )6c@S9dsh�UYd�[ `�b�U�tuZ���dsVCX�b�Z�]^]3U*h�lsU&S [�Z X1c^h�l6X�d h�h�U X1`�c^d h�c@S"`FVJU&S"U Z�V�X�b�U*V�SCz ��Z&h�S"dsh� y \�VJV*o({4| |s~ � $ X�D]3dS �U*_oA{4| |�{&��w �Rh�ds`�b�U4V�V�U&ZsS"dsh:tuZ*_jQ�U6`Jb�UaX1d hTX1U*k�`J\�Z�]Di c � X1\�] �`�c3U Svc3h Wd ]^WU&inc3h Z�h�S�eFU*VJc3h�l�`Jb�c-S'�\�U&S�`�c3dsh S�Z&`�c@S [�Z X�`�d VJc3]^_ f [Od V6U4r�Z&tjk�]3Uxo b�d�e X1ds\�]-i Z]3dd&� �O\�kL`�Z&Q�]3U6Q�Uac3tjk�]3U*taU*h `�U4i c^hLZjk�Z&V�Z&]3]3U4]Di�c-S�`�VJc3Q�\�`JU&i�S"`JV�\�X�`�\�VJUo Z�h�i:b�d�e eFds\�]-iZ�hnc^h�WU S"`�c^lZ&`�d V ��h�d�e eCb�U*h;S"b�UYb�Zsini�U4`�U&X1`JU&i c^` �

�.U*WU*V�`Jb�U*]^U&S�S�oF`�b�U �\�U&S�`�c^d h d�[0eCb�U*`Jb�U*V�X1d h�h�U&X1`Jc3d h�c-S"`mtjd i�U*]@S i�d c^h�i�U*U&i i c � U*Vc3h Zj[O\�h�X1`Jc3d hTZ�]CS�U*h�S�U [OV�dst i�\TZ�]FVJd \�`JUutjd i�U*]@S VJU*tuZ&c3h�S�Znk�c3Wd `�Z�]Dd h�U��9cB[.c3` X*Z&h Q�US"b�d&eChj`Jb�Z�`D`�b�UR`�eFdYtjd i U*]-S(Z&V�U.c3h6[�Z X1` 24� ��1��$ G ��� �3� � U��\�c^W Z&]3U*h `*o&`�b�U�i�U4Q�Z�`JURe,d \�]@iEh�d]3d h�l U*VCQ�U Z S�\�Q�S�`�Z�h `�c@Z�]Adsh�U Z�Q�d \�`.`�b�U [O\�h�i�Z�tmU*h�`�Z�] k�V�c^h�X1c3k�]3U&S(\�h�i U*V�]^_�c^h�l ��\TZ S"c^V�U*l �\�]-Z&V9t Z�k�k�c^h�lS�o Q�\�`DV�Z�`�b�U*V,Zv]3U S�S c^h�`JU*V�U&S�`�c^h�l�c3tmk�]3U*taU*h `�Z&`�c3dsh�Z�]^c-S�` i�U*Q�Z&`�U z��Z�]-Z g d i�d V� ! _�]^_�S�b�_ hAo {*|(C�C���w

� b�c3]3UYc^`Cc-SF`�VJ\�UY`�b�Z&`R`�Z�c^]3d VJU&i `JU&X�b�h�c!�\�U&S([Od VCc^]3]3\�tjc3h�Z&`�c^h�lY`�b�U c3h `�U*VJh�Z�] S"`�VJ\�X1`J\�V�Ud�[Ch�U*`�eFd V���SNZ�V�Uah�ds` _U*`NZ*W Z&c3]@Z�Q�]^Uo S"d tmU l U4h�U*V�Z&],S"`�Z&`�c@S"`�c@X*Z�]�`�U&X�b�h�c ��\�U SR`�b�Z&` Z�V�UmZ�] �V�U&Zsi�_:eCc@i�U*]^_:\�S�U&iLc3hL`Jb�UuS�d X1c-Z&].S�X1c^U*h�X1U&SazpZ&h�iLU*]-S�U*eCb�U*VJU �YZ&V�UjQ�U*c^h�l#Z�k�k�]3c3U i:tjd VJU

���[=>2@0'2G<Q�+24)+$-(/GI790[a[(/,/,PQ;2D�(/0+)+F90'0-24D ( 7VA G<&'2?D%2@$S3M( ,P(/7�R=;3M19$'2@& � b��� 2@A (/79(/0+)+2@7�$NG6^�� 3M&'&TJ 0HU�������IZ aR2@,/,��c5�79G6a[7 ,/2@_<2@,/0[G6^N367;3M, .�0-( 0Tb

Page 29: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

h ������������� �������������������������

Z�h�iutjd VJUv`Jd lxZ�c^h#ZEVJ\�i�c3tmU*h�`�Z�VJ_ c^h�S"c^l b `Cc3h `�dah�U*`�eFdsV � [O\�hTX1`�c^d h�Z&]3c3`�_w � b�U&S�U c^h�X1]3\Ti�UW�c@S"\�Z&]3c � Z�`�c^d h `�U&X�b�h�c ��\�U Sv[Od Vjb�c^l b���i�c^tjU*h�S�c3d hTZ�]NS"k�ZsX1U&SjS�\�X�b Z Sjb�c^U*V�Z&V�X�b�c-X*Z&].X1]3\TS"`�U4VZ�h�Z&]3_�S"c-SYz �(]^tuZ�hAo {*|s| ~��o k�VJc3h�X�c3k�Z&](X1dstjk�d h�U4h�`.Z&h�Z�]^_�S�c-S z � ]^tuZ�h oA{*|(Cs|���oAZ�h�i�X4Z�h�dsh�c �X*Z�] i�c@S�X1VJc3tjc^h�Z�h `DZ&h�Z�]^_�S�c-SYz � c3]^U&S�� P.]3]3c^]-Z o {*|s| }��w

�.duS"c^l h�c(� X*Z�h `YZ&`�`�U4tjk�`Cb�ZsS Q�U*U4h�tuZ i�UYc^h�`�b�UaX1dsh�h�U&X�`�c3dsh�c-S�`R]^c3`JU*V�Z&`�\�VJU `�d Z�k�k�]^_S"\�X�bn`JU&X�b�h�c!�\�U&SC`�djh�U*`�eFd V���SC`�V�Z�c^h�U&i dsh%�\�ZsS"c3VJU*l \�]-Z�V.tuZ&k�k�c3h�l `�Z S ��S1o `�d�i�U*`JU*V�tjc^h�UeCb�U*`�b�U*V `Jb�U*_#c3tjk�]^U*taU*h�`NZ [O\�h�X�`�c3dsh�Z�].i \�Z�]CVJd \�`JUw ��Sve,U*]3]�o h�d#Z&`�`�U4tjk�` bTZ S Q�U*U*htuZ i�UN`�dmi�U*WU*]^d kuZ VJc3l dsV�ds\�SRtjU*`Jb�d i�ds]3d ls_j`�daZ&h�S"e,U*V.`�b�c@SFc3tjk�d VJ`�Z&h�` ��\�U S"`�c^d hAw

q hu`�b�c-SF`�b�U&S"c@S q `�b�U*V�U1[OdsV�UYk�VJd k�dS�U `�dmZ i�i�V�U&SJS `Jb�U�[Od ]^]3d&eCc3h�l6VJU&S"U Z�V�X�b �\�U&S�`�c3dshAf

�Rd [OU*U&i[Od V�eKZ�V�i X�d h�h�U X1`�c^d h�c@S"`Fh�U*`�eFd V���SCi U*WU*]3dskjZ6i \�Z�]AVJd \�`JU [O\�h�X1`�c^d h�Z&]Z�V�X�b�c^`�U&X�`�\�VJUR`Jd c^tjk�]3U4t U*h `��\�Z S�c3VJU*l \�]@Z�VCtuZ&k�k�c^h�lS �

� b�U 5 ����� G � Q�_jeCb�c-X�b q Zsi�i�V�U S�SC`�b�c@S ��\�U S"`�c^d huc-S.Z S9[Ods]3]^d�e.S�f

� j U4W�c^U*eL`�b�URU*W c-i U*h�X1UKX1d h�X�U*V�h�c^h�l�`Jb�UCU*r c-S"`JU*h�X1U,d�[ Z i�\�Z&]�V�ds\�`�U.c3hmX1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��S1o`�d i�U4`�U*VJtjc3h�U,eCb�U*`Jb�U*VD`�b�U4V�U.c-SDS"c^l h�c(� X*Z�h `DU*W c-i�U*hTX1UF[Od VD`�b�U�U*r c-S"`JU*h�X1Ud�[ S"\�X�b�Z0[O\�h�X1`�c^d h�Z&] S"`JV�\�X1`J\�V�U��

� q [.`�b�U*VJU c@S S�c3l h�c � X*Z&h�` U*W c-i�U*hTX1Uo i�U*WU*]^d k Z 5 ���-� G � G � G ��� `�d;Z�h�S�eFU*V6`Jb�UuZ&Q=d&WU��\�U&S"`Jc3d h oRQ _ V�c^l dsV�d \TS"]3_ X�d h�S�c-i�U*VJc3h�l Z�]3]Nc-S�S�\�U&Sj`�bTZ�`�Z�VJc-S"U#ZsSjk�Z�VJ` d&[aS�\�X�b ZS"U&Z&V�X�bAoDZ�hTi Q _:`Jb�d VJd \�lsb�]3_ i�c@S�X1\�SJS"c^h�l#Z�h�i i�U1[OU*hTi�c3h�l#Z&]3],d k�U*V�Z&`�c^d h�Z&]3c � Z�`�c^d h�SV�U��\�c^V�U&i �

� � S"c^h�ln`Jb�c-SYtjU*`Jb�d i�d ]^d ls_o(V�U*k�]3c-X4Z�`�UmZ�S"U4]3U&X1`Jc3dsh:d&[NS"`�\Ti�c3U&Sv[OVJd t `�b�Um]3c3`JU*V�Z&`�\�VJUeCb�U*VJU X�d h�h�U X1`�c^d h�c@S"`#h�U*`�eFdsV ��Snb�Z*WU S�\�X*X1U S�S [O\�]3]3_ c3tjk�]^U*taU1h `�U&i �\�Z S�c3V�U4l \�]@Z�VtuZ�k�k�c3h�lxS1oCZ&h�i U*r�Z�tjc^h�Uj`Jb�U&S"U;X1d tmk�V�U*b�U*h�S"c^WU*]3_n[OdsV `Jb�U�U*r c-S�`�U*h�X�Ujd�[0ZLi�\TZ�]V�ds\�`�Uw

����� ����� � ��������� �����������

q h WU&S�`�c3lxZ�`Jc3d hTSEc^h `�b�c@S `�b�U S"c-SaeCc3]3].Q�U:]^c3tjc^`�U&i#`�d `�b�U#X�d h�h�U X1`�c^d h�c@S"`ak�Z�V�Z i�c^l t�o.Z�hTiS"k�U&X1c(� X*Z�]^]3_o`Jd 2&���J�"2 G ��8(����a�=����8 G ��>*� `Jb�Z�`.c3tjk�]3U*taU*h` ��\TZ S"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxS1w

Page 30: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��������� ��� ��������@��� ^

q b�Z*WU�X�b�dS�U*ha`�d6Zsi�b�U*VJUR`Jd `Jb�c-S(V�U S"`�VJc-X1`Jc3dsh [Od VF`Jb�UNS"c3tmk�]3U,V�U&ZsS"d hu`Jb�Z�`Dk�V�Z X1`Jc-X*Z&]3]3_Z�]3] X1d h�h�U&X1`�c^d h�c@S"`aV�U&S�U&Z�V�X�b dsh �\�ZsS"c3VJU*l \�]-Z�VmtuZ�k�k�c3h�lxS b�Z SjQ�U*U*h X4Z�V�VJc3U&i ds\�`u\�S"c^h�l[OU*U&i�[OdsV�eCZ&V�ijh�U*`�e,d V ��S1o `�_�k�c@X*Z�]^]3_6eCc^`�bu`�b�VJU*U �O]-Z*_U*V�SRz%c�w Uw^od h�UYc3h�k�\�`C]-Z*_U*V4od h�UYb�c@i�i�U*h]-Z*_U*V*o Z&h�i dsh�U ds\�`�k�\�`C]-Z*_U*V1��w

� b�c-SAV�U&S�`�V�c@X1`�c^d h0i�dU&S h�ds` \�h�i�\�]^_v]^c3tjc^` `Jb�UFlsU*h�U*V�Z�]3c^`�_Rd&[ `Jb�UCX�d h�X1]^\�S"c^d h�SAV�U4k=dsV�`JU&i oQ=U X*Z�\�S�U�c3`Db�ZsS9Q�U*U*h S"b�d&eChj`Jb�Z�`,`�b�VJU*U �O]-Z*_U*V(h�U4`"e,d V���S�o�lsc3WU*haS�\�� X1c3U*h `(VJU&S"ds\�V�X1U S1o�Z&V�U����$-I&�����4� ���1�� � G ��$-56� � G ��� ��`�b�Z&`Rc@S1o�`�b�U4_nZ&V�U0X*Z�k�Z&Q�]3U d�[,Z&k�k�VJd�r c3t Z�`�c^h�luz%Q�\�`�h�ds`Rh�U X��U&S�SJZ�V�c^]3_a]3U&Z&V�h�c^h�l��,Z&h�_a[O\�h�X1`Jc3d huQ�U*`�eFU4U*hj`�eFd'��h�c^`�UYS�k�Z X1U Svz �Rd VJh�c � o &`Jc3h�X�b�X1dst Q�Uo �� b�c3`JUoD{*|(Cs|���w � b�U*_#Z�VJU `Jb�U*VJU1[Od VJUjX*Z&k�Z�Q�]3Uad�[Cc^tjk�]^U*t U4h�`Jc h�ljZ&]3]��\�Z S�c3VJU*l \�]@Z�V tuZ�k��k�c3h�lxS1w

��� � � � �������� ���� � ���

� b�c-SD`�b�U&S�c-S(c3h WU&S�`�c3lxZ�`JU&S(`�b�U ��\�U&S"`Jc3d had�[ eCb�U*`�b�U4VCX1dsh�h�U&X1`Jc3dsh�c-S�`9tmd i�U*]-S(d&[ �\�Z S�c3V�U4l \��]-Z�VCt Z�k�k�c^h�lSFc^tjk�]^U*t U4h�`DZ [O\�h�X�`�c3dsh�Z�] i \�Z�]AVJd \�`JUw q hu`�b�c-S.X�b�Z&k�`�U4V*o �RE���G�/`L� � o�`�b�U`�d k�c-X�eCZsS c^h�`JV�d i�\�X�U&ijZ�hTi `�b�UvVJU&S"U Z�V�X�b ��\�U&S"`Jc3d h�S�`�Z�`JU&i w

q h �RE���G�/`�� & o q Q�VJc3U ��_YVJU*W�c^U*eL`Jb�URk�V�c3hTX1c3k�]^U&SAd�[ `�b�UNS"_ taQ=ds]3c@X ����3� ��� G �"� `�b�U4d V�_ c3hl U*h�U4V�Z�]�o�Z&h�i Dd ]3`Jb�U&Z&V�` $!S ���� � � G ��"� `Jb�U*d VJ_jc3hmk�Z�VJ`�c-X�\�]-Z&V*w � b�U�`Jb�U*dsV�_jc@S9V�U4tuZ�V�� Z&Q�]3_S"c3tmc3]-Z&V `Jd b�d&e Z�VJ`�c(� X1c-Z&]YS"k�U*U X�b S�_�S�`�U*tuSmZ�V�U#c3tmk�]3U*taU*h`JU&iLd h i�c3lsc3`�Z&] X1d tjk�\�`�U*V�S1oS"\�lsl U&S�`�c3h�ljZaS"`JV�d h�l ]^c3h �a`�dmZ X�d tjk�\�`�U*VDtjU*`�Z�k�b�d VCd�[ X1dsl h�c^`�c3WUNV�U&ZsS"d h�c3h�l�w

P.h�UuVJU&Z S�d h [Od V6`Jb�U�i d tjc^h�Z�h�X�Ujd�[Y`Jb�U�i�\�Z&]RVJd \�`JUnZ&k�k�VJdZ X�b eCZsSE`Jb�Uu]-ZsX �Ld&[ ZX1V�U&i c3Q�]^Uo eFdsV � c3h�l0Z�]^`�U*VJh�Z�`Jc3WUw q h �RE5��G�/`L� , q i�c@S�X1\�SJS9`Jb�UYX1dsh�h�U&X1`Jc3dsh�c-S�`Fk�Z&V�Z i c3l t;oeCb�c-X�b6b�Z S,i�U*]^c3WU*VJU&i�h�\�tmU*V�ds\�S tjd i�U4]-S X*Z�k�Z&Q�]3U.d�[ S"\�X4X1U&S�Sp[O\�]3]^_ c^tjk�]3U4t U*h`Jc3h�lC]^c3h�ls\�c-S �`�c-X��\�Z S�c3V�U4l \�]@Z�VFt Z�k�k�c^h�lS�w &\TX�bjtmd i�U*]-S �1��=�J�� `Jd b�Z*WUNi�c-S�k�U*h�S"U i eCc3`Jb Dd ]^`�b�U&Z&V�` $ SS"`�VJd h�l X1]@Z�c^t `�bTZ�`,ZYi�\�Z�]�V�d \�`�UNZ�V�X�b�c^`�U&X1`J\�V�U,c-S VJU��\�c3VJU&iv[Od VDS ��c^]3]^U&ivVJU&Z i�c^h�lYd�[ � h�l ]3c@S"beFd V�i�S1o Q�U&X*Z�\TS"Ua`�b�U*VJU c@S�h�d G /*I4$ G �x� i�\TZ�]DV�ds\�`�Uj`JduQ=Ua[Od \�h�i#c3h�`�b�U h�U4\�V�Z&]Fh�U*`�e,d V �Z�V�X�b�c^`�U&X1`J\�V�Uxw

�.d�e,U*WU*V4o c3h �RE5�<G /`L� � q VJU*W c3U*e U*W c-i�U4h�X1UC`�bTZ�`CS�\�l lsU&S"`�S9`Jb�Z�`KX1d h�h�U&X1`�c^d h�c@S"`Dh�U*` �eFd V���S.Z�hTi�i�\�Z�] V�ds\�`�U0S"_�S"`JU*tuSFtuZ*_aQ=UY[O\�h�X1`Jc3dsh�Z�]^]3_jU��\�c^W Z&]3U*h `*w y d `Jbnk�b�c3]3dxS"dsk�b�c-X4Z�]X1d h�S�c-i�U4V�Z�`Jc3dsh�SDZ�h�i c^h�i�c^V�U&X1` Q�U*b�Z*W c3d \�V�Z�]�tjU Z S"\�V�U&S d&[Ah�U4`"e,d V���S(eFU4V�U.X1dsh�S"c@i�U*V�U i oZ�hTic3`FeKZ S9[Ods\�h�i `Jb�Z�`C`Jb�U*V�UNU*r�c@S"`�SFS"c^l h�c(� X*Z&h�`,U*W�c@i�U*h�X�UF[Od V.Z6i�\�Z&] VJd \�`JUvc^huX1dsh�h�U&X1`Jc3dsh�c-S�`

Page 31: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

C ������������� �������������������������

S"_�S"`�U4tuS1w q hn[�Z X1`4oT[OdsVYd h�U h�U*`�eFdsV � o=U*W c-i U*h�X1U Z�`Y]^U&Z S�`RU��\�Z&] `JdnZ&h�_j[Ods\�h�i�c3hnb \�tuZ&hX1d lsh�c3`Jc3d hueKZ S.i�U*tjdsh�S"`JV�Z�`JU&i w

�NZ W c3h�l�U&S"`�Z�Q�]^c-S"b�U&iLZ�V�Z�`Jc3dsh�Z�]^U [OdsV `Jb�UuV�U&S�U&Z�V�X�b o(c3h �RE5�<G /`L� � q `�\�VJh `JdLi U �WU*]3dsk�c3h�l Z 5 ����� G � G � G ��� [OdsVnta_LV�U S"U&Z&V�X�bAw q i�c@S�X1\TS�Sjb�d&e Z i�\�Z�]YVJd \�`JU:tjc^l b ` Q�Uc3tjk�]^U*taU*h`�U&i6c3hj[OU*U i�[Od VJeCZ�V�i h�U4`"e,d V���S�o�Z�h�inQ�VJc3U �T_jV�U*W c3U4e k�Z S�`YZ�`J`�U*tjk�`�SFc3hu`Jb�U ]^c3`��U*V�Z&`�\�VJUYZ�`.i�U4`�U&X1`Jc3h�lYdsh�Uw q `FeKZ SCi�U&X�c-i�U&ia`�b�Z&`F`�b�UvQ�U&S�`CZ&k�k�V�dxZ X�bueFd \�]-ijQ�U�`�daS�U*]3U&X�`ZRtjU*`Jb�d i�d ]^d ls_ `�bTZ�`(tuZ �U&S [OU*e Z S�S�\�tjk�`Jc3dsh�S Z&Q�d \�`,b�d&e ZYi�\TZ�]�VJd \�`JUCc-S c^tjk�]3U4t U�h�`JU&ic3hLb�c@i�i�U*h#\�h�c^`6S�k�Z X1Uxw:P.h `Jb�c-SYQ�Z S�c-S�oDS"`�Z&`�c@S"`�c@X*Z�]DW c-S�\�Z�]^c �&Z&`�c3dshL`�U X�b�h�c!�\�U&S z�S"\�X�b Z Sk�V�c^h�X1c3kTZ�],X1d tmk=dsh�U*h `�SYZ�hTZ�]3_�S"c@S��.eFU4V�UmX�b�dxS"U*h `�dnU4r�Z&tjc3h�U6`Jb�Uab�c-i�i U*h:\�h�c3`0S"k�ZsX1Ujd�[`�V�Z&c3h�U i h�U*`�eFd V���S�w �C[O`�U*V ��V�S"`ac3h WU&S"`Jc3lxZ�`�c^h�l�`�b�UnS�\�c3`�Z�Q�c^]3c^`"_#d�[vS"\�X�b `�U&X�b�h�c ��\�U Sv[Od Vc3h `�U*VJk�V�U*`Jc3h�l�h�U*`�eFdsV � S�`�VJ\�X1`�\�V�Uo q Z�k�k�]^c3U&iL`Jb�U*t `JdLZnVJU*k�]3c@X*Z�`Jc3dsh d&[YZ�h�U*`�e,d V �#[Od VtuZ�k�k�c3h�l � h�l ]3c@S"b�eFd V�i�SC`�daS"ds\�h�i�S�w

�.d i�\�Z&]vVJd \�`JU�eCZsSm[Ods\�h�i o.Q�\�`j`Jb�U&S�U#S"c3ta\�]@Z�`�c^d h�S6]3U i `�d `Jb�U�c3h�S�c3lsb�`j`Jb�Z�`m`�b�US"`�Z&h�i�Z&V�i�d k�U*V�Z&`�c^d h�Z&]3c � Z�`�c^d h�d&[D`�b�U6`JU*V�t S # V�U4l \�]@Z�V $�Z&h�i%# U*r�X1U*k�`Jc3dsh $�c@S h�ds`YS"\�c3`�U in`�d`�b�UNX1d h�h�U&X1`Jc3d h�c-S"`,k�Z�V�Z i�c^l t�w � h�U*eYo�i�_ h�Z&tjc-XCi�U"��h�c3`Jc3dsh c@S9V�U ��\�c^V�U&i o `�b�Z&`C`�Z �U&S(c3h `�dZ X*X1ds\�h `(`�b�U.eFU4]3] �OU&S�`�Z�Q�]3c-S�b�U&i�[�Z X1`(`Jb�Z�`Ddsh�U�X4Z�h�h�ds`Dk�V�U&i c-X1` c3hmZ i�WsZ&h�X1UCeCb�Z&`FtuZ&k�k�c3h�lZEh�U4`"e,d V�� eCc^]3] c^h�i�\�X�U [OVJd t Z6l c^WU*hj`JV�Z�c^h�c3h�l6V�U*lsc3tjUw

� d�`�b�c-SvU4h�i o q VJU*W�c^U*e c^h �RE���G /0�� `Jb�Ujc3h `�\�c3`�c^WU h�ds`�c^d h d�[�#!U*r�X�U*k�`�c^d h�S"$3o Z�hTik�V�dsk=dxS"U�Znl U4h�U*V�Z&]Ci�U"��h�c3`Jc3dshLd�[.U*r�X1U*k�`�c3dsh�S1o�Z S e,U*]3],Z S6Z�i U���h�c^`�c3dshL`�Z&c3]^d V�U i:`�d�`�b�UX1d h�h�U&X1`�c^d h�c@S"`ak�Z�V�Z i�c^l t�w � S"c3h�l:`Jb�c-S h�U*e ��� ���56$- i�U"��h�c3`Jc3dshAoCZ�hTi `Jb�U�S�`�Z�`Jc-S�`�c-X4Z�]`�U&X�b�h�c ��\�U Svi c-S�X�\�S�S�U&iLc3h Db�Z&k�`�U4V % o q Z�hTZ�]3_ �*U&i#`�b�Uuh�U*`�e,d V ��[OV�dst Db�Z&k�`�U*V�&�`Jb�Z�`i�c-S�k�]-Z*_U&i:`Jb�UutjdS�` U*W c-i U*h�X1Ujd&[YX�d h `�Z�c^h�c3h�l#Z:i�\TZ�]CV�ds\�`�Uxw �R]3`Jb�d \�lsb `Jb�c-S6S�`�V�Z&`�U*ls_S"b�ds\�]-iul c3WUN`�b�UYQ�U&S"`.X�b�Z&h�X1U S"d6[�Z�VCd&[,i�c-SJX1d&WU*V�c^h�l6Z6i \�Z�] V�ds\�`�Uo�h�d h�UYeCZsSK[Ods\�h�i w

q hj`Jb�U'Dd h�X�]3\�S�c3d hTSCX�b�Z&k�`�U4VYz �RE���G /0�� � ��o�`Jb�UYV�U&S�U&Z�V�X�bmc-SFS�\�tjtuZ&V�c �*U&i6Z�hTi X�d h��X1]3\�S�c3dsh�SDi�V�Z*eChAw �R]3`Jb�d \�lsb h�d6i�\�Z&]�V�d \�`�U.eCZ S [Ods\�h�i6c3ha`�b�UCh�U4`"e,d V���SDX1dsh�S"c@i�U*V�U i o `�b�c-Si�dU&S h�ds`CzpZ&h�iaX*Z�h�h�d `1� k�V�d&WUF`Jb�Z�` X1d h�h�U&X1`�c^d h�c@S"` h�U*`�eFdsV ��S ����I���� i�U4WU*]3dsk ZC[O\�h�X1`Jc3d hTZ�]i�\�Z�]AVJd \�`JU Z�V�X�b�c^`�U&X1`J\�V�Uxw �.d�e,U*WU*V4o�`Jb�UYV�U&S�\�]3`�SFi�dmS"`JV�dsh�l ]^_uS"\�k�k=dsV�`.`�b�U )ak�VJU*W c3d \TS"]3_\�h�S"\�Q�S"`�Z�h `�c-Z&`�U&i )�ZsS�S�U*V�`Jc3d h `�b�Z&`6X1dsh�h�U&X1`Jc3dsh�c-S�`�h�U*`�eFdsV ��SYX1d h�S�`�c^`�\�`JUjZuW�c@Z�Q�]^UaX1d t��k�\�`�Z&`�c^d h�Z&]CZ�]^`�U*VJh�Z�`Jc3WUa`�d�`�b�Uui \�Z�],V�d \�`�Ujk�Z&V�Zsi�c3lst�w q tjk�]3c@X*Z�`Jc3dsh�SRd�[.`Jb�c-SYeFdsV ��[Od Vk�S"_�X�b�d ]3dsl c@X*Z�] V�U&S�U&Z�V�X�b6c^h�`JdR`Jb�U��\�U&S"`Jc3dsh6d�[ eCb�U*`Jb�U*V ��� 56���� c3tjk�]3U*tjU�h `AZYi�\�Z&]�V�ds\�`�U

Page 32: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��������� ��� ��������@��� |

Z�V�UY`Jb�U*h�i�c-SJX1\�SJS"U&i w

Page 33: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

{*~ ������������� �������������������������

Page 34: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����� �

� � � � � � � � � ��� � � � ����

��� ��� � � ���� ���� ��

� b�c-S,X�b�Z&k�`�U4VFi U&S�X1VJc3Q�U&S(`�b�U�Q�Z S�c-XC`�U*h�U*`�SDd�[A`Jb�UYi�\TZ�] VJd \�`JU�`�b�U*d VJ_oeCb�c-X�bE[OdsVF`Jb�URkTZ S"`� ~ _U&Z&V�SCb�Z S�Q�U*U*h�`�b�Uai d tjc^h�Z�h `Ck�Z�V�Z i�c^l t c3hnU4r�k�]@Z�c^h�c3h�lab�d&e b�\�tuZ�h�S )�Z&h�ind `Jb�U*VX1d tjk�\�`�Z&`�c3dsh�Z�] i�U*W c-X1U S )mc3tjk�]^U*taU*h` ��\�ZsS"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxS1w

q h�`Jb�U k�ZsS"`Y`�U4hn_U&Z&V�S1o `�b�U0X1d h�h�U&X1`�c^d h�c@S"`YZ&k�k�VJdZ X�b�b�ZsSvZ&V�c@S"U*h#ZsS�ZjS"U4V�c3ds\�S�X�b�Z�] �]3U*h�lsUR`Jd `Jb�U�i \�Z�] V�d \�`�U�`Jb�U*d VJ_w � b�UNX1V�c^`�c@X*Z�]�i c � U*V�U4h�X1U.Q=U4`"e,U*U*ha`�b�U.`�eFd `�b�U*dsV�c^U&S(]3c3U Sc3h#eCb�U*`�b�U*V6Z�i�c-S�`�c3hTX1`�c^d h�c-SYtuZ i UoAc3h#`�b�U6[O\�h�X1`Jc3dsh�Z�]KZ�V�X�b�c^`�U&X1`J\�V�Uxo Q�U*`�eFU*U*h#V�U4l \�]@Z�VZ�h�i U*r�X1U*k�`�c3dsh c3`�U4tuS1w Dd h�h�U&X1`�c^d h�c@S"`jtmd i�U*]-S6Z&]3]^U*l U&i ]3_LtuZ �Ujh�d S�\�X�b i�c@S"`�c^h�X1`Jc3d h oeCb�c3]^Uui�\�Z&]RVJd \�`JU tmd i�U*]-SYU*r k�]3c@X1c3`J]3_#i�d�w � b�U�S�U*`6d�[ i d tuZ&c3hLc^`�U*tuSYc-S6X1dsh�X1U*k�`�\�Z&]3]3_i�c3W c-i�U i:Q�_ `�b�U;i�\�Z�].V�ds\�`�Uu`Jb�U*d VJ_ c3h `�d�`�eFd S"U*`�S1oDU*r�X1U*k�`Jc3d h Z&h�i VJU*l \�]@Z�V4oF`�b�Z&`jZ&V�Ub�Z�h�i ]3U&ijQ _j`�eFdmi�c � U*VJU*h�`,tjU&X�b�Z�h�c-S"t S1w � b�c-SCc3h `�U4V�h�Z&]Ai�c@S"`�c^h�X1`Jc3d h�X1dsh�`JV�ZsS"`�SCeCc3`Jbu`�b�UzpZ�k�k�Z�VJU*h�`J]3_��Y\�h�cB[Od V�t X1d h�h�U&X1`�c^d h�c@S"`6b�Z&h�i�]^c3h�l#d�[NQ�d `�b `�_ k�U&S d�[YkTZ�`�`JU*V�hTS1oDeCb�c-X�b c-Si�c-SJX1\�S�S�U&ijc3hu`�b�Uvh�U*r�`.X�b�Z&k�`�U*V4w

&x`�V�c@X1`�]^_�S"k�U&Z"� c3h�l�o `Jb�U6`�U*VJt #Bi�\�Z&](V�ds\�`�U6`Jb�U*dsV�_ $=dsh�]3_;Z�k�k�]^c3U&S.`�dj`Jb�U6k�S"_�X�b�d ]^d l c �X*Z�]DZsX*X1ds\�h�`Yd&[F`JU*r `���S"k�U*U&X�b#X1d h WU*V�S"c3dsh#i�U*WU*]^d k�U&iuQ�_ Dd ]3`Jb�U&Z&V�`azpZ&h�i ds`�b�U4V�S��.c^h�`�b�U{*|a^ ~ $!S1w �Rd&eFU*WU4V*o q eCc3]3] Q�U \TS"c3h�lj`�b�U6`JU*V�t `�d�i�U&SJX1V�c^Q�U6Z�]^](V�\�]3U �OQ�Z S�U&i�`�b�U*dsV�c^U&S `Jb�Z�`k=dxS"`J\�]-Z&`�Uj`Jb�U U4r�c@S"`�U4h�X1U d&[C`�eFd�S�U*k�Z�V�Z�`JUjc3h `�U*VJh�Z�]�tjU&X�b�Z�h�c@S"tuS9[OdsVYb�Z�h�i ]3c3h�lnV�U4l \�]@Z�VZ�h�iuU*r�X�U*k�`�c^d hjkTZ�`�`JU*V�hTS1w q h�t _ai U&S�X1VJc3k�`Jc3dsh q eCc3]^] Q�U \�S�c3h�l Dd ]^`�b�U Z�V�` $ SFtjd i U*]AZsSRZ&hc3]3]^\�S"`JV�Z&`�c3WUNU*r�Z&tjk�]^Uo�Q�\�`�eCc^`�b;Z�h#U*tjk�b�ZsS"c@SFd h�`�b�dS"U [OU Z�`�\�V�U&SR`Jb�Z�` Z�V�UaX�d tjtjdshu`�d

{ {

Page 35: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

{D� ������������ � � ����� � � � � ��� ����� �������O���

Z�]3] S�\�X�b tmd i�U*]-S�w� b�UYz%l U4h�U*V�Z&]%� i�\�Z&]�V�ds\�`�UC`Jb�U*d VJ_6X*Z&h6Q�U.S"U*U*haZsS(Z�`�b�U4d V�_Yd&[ h�d `Dd h�]^_Yb�d&e b \�tuZ�hTS

b�Z�h�i ]3U ��\TZ S"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxS1o�Q�\�`.Z�]-S�d b�d�e ���� X1d tmk�\�`�Z&`�c^d h�Z&]AS"_�S"`JU*t i�dU S1w

� �������� � ��� �

q h6`Jb�U {*|(hs~ $!S1o�ZYtjd&WU*taU*h` X�bTZ�tjk�c^d h�U i Q�_ �RU*eFU4]3]�Z�h�i�&c3tmd huz�{4|(h {���o�Z�h�i Db�d tuS ��_z Db�dstuS � _�� �NZ�]3]^Uo�{4|(h(C�(k�dS�c3`JU&iE`Jb�Z�`KX1d lsh�c3`Jc3WU,k�V�d X1U S�S"U S9c3hal U4h�U*V�Z&]poZ&h�i ]@Z�h�ls\�Z�lsUk�V�d X1U S�S"U S c3h k�Z�VJ`�c-X�\�]-Z&V*oCX1ds\�]-i Q�U&S"`jQ�U�U*r�k�]-Z�c^h�U&i Q�_LVJ\�]3U �%Q�ZsS"U&i `Jb�U*dsV�c3U S1w q h `�b�c-S[Od V�ta\�]@Z�`�c^d hAosk�V�d X1U S�S"U SFS"\TX�bmZ SD`�b�U�k�V�d i�\�X�`�c3dshjd�[ lsV�Z&tjtuZ�`Jc-X*Z&]�S�U*h `�U*h�X�U&S1o dsVFlsU*h�U*V�Z�]k�V�dsQ�]3U*t S�d ]^W�c^h�l�o X1ds\�]-i�Q�Uji�U S�X1VJc3Q�U&i#Z Sv\�`�c3]^c �*c^h�luZuS"U4`vd&[.c3h `�U*VJh�Z�]�V�\�]^U&S�� `�b�UaQ�V�Z&c3hc-S zO]3c3`JU*V�Z&]3]^_=�,ZuX1dstjk�\�`�Z�`�c^d h�Z&]Di�U*W c-X�Uv`Jb�Z�` Z&k�k�]3c^U&S�S�\�X�b�VJ\�]3U SR`�d�S"_ taQ=ds]3c@XvX�d l h�c3`�c^WUc3`�U4tuS9z ! c3h �U*V4o�{4| | {�� ��Z&h�i6`�b�UCtuZ���d V(`�Z S �6d&[A`Jb�UCV�U&S�U&Z�V�X�b�U*V*o c^haZ�h _6S�k=U X1c � XCX�d l h�c3`�c^WU��U*]-i o�c-SF`Jd �Th�ijd \�`.eCb�Z�`.`�b�U&S"UYV�\�]3U&SCZ&V�Uw

� b�U U*r c-S�`�U*h�X�U�d�[DVJ\�]3U SFU*r�k�]-Z�c^h�SCb�d&e b�\�tuZ�h�SCZ&V�U0Z�Q�]^Uv`Jd � ���=���J� �B$��&� `�djh�d�WU4] U*r �Z�tjk�]^U&S��D[Od VaU*r�Z&tjk�]^Uo(b�d&e U*]-S�UnX�d \�]@i d h�U�i�U*`JU*V�tmc3h�UjeCb�U*`�b�U4VjZ#X1d tmk�]3U*`JU*]3_�h�d�WU4]S"U*h `�U*hTX1U�c-SDl V�Z�tjtuZ&`�c@X*Z�]�d VCh�d `*o�cB[(h�d `CW c-Z l U4h�U*V�Z&] k�VJc3h�X�c3k�]^U&S1o d VCV�\�]3U&S�o�d�[�l V�Z�tjt Z�`��c-X*Z&]3c3`�_ � � b�UYU*r c-S�`�U*hTX1U�d�[ c3h `�U*VJh�Z�] V�\�]^U&SFeFds\�]-i�Z�]-S�djZsX*X1ds\�h�`C[Od V.tuZ&h�_ad `Jb�U*V.Z S�k�U&X1`�Sd�[,b�\�tuZ�huQ�U*b�Z*W c3d \�V �AS�U*U &tmc3`�b o�AZ�h�lxS"`�dshAo Z�h�i �.c-S"Q�U*`J` zJ{*|s|(���C[OdsVYZ V�U4W�c^U*e d&[,`�b�U[OU&Z�`J\�V�U&SFd&[Db \�tuZ�hmV�U&ZsS"d h�c3h�lmZ SJX1V�c^Q=U i `Jd `Jb�UY\�S"UYd&[DV�\�]^U �OQ�Z S�U&iuS"`�V�Z�`JU*l c^U&S1w

� b�UCi�dstjc3h�Z&h�X1U(d&[ `�b�UDV�\�]3U �OQ�Z S�U&i Z&k�k�VJdZ X�b6c3h `�b�c@S U*V�ZCeCZsS h�ds` ]^c3tjc^`�U&iC`�d.`�b�U4d V�c^U&Sd�[ X1dsl h�c^`�c^WU9tmd i�U*]3]^c3h�l�w ��SAeFU*]^]po*tuZ&h�_ �RV�`Jc � X1c@Z�] q h `�U4]3]3c^l U*hTX1U(Z&k�k�]^c-X*Z&`�c3dsh�SAeFU*VJU9QTZ S"U id hu`�b�UY\�S�U�d�[�U*r k�]3c@X1c3`DVJ\�]3U&S.zpS�U*Uo�[OdsVCU*r�Z�tjk�]^U&S1o � c^h�S"`Jd hAoA{4|(C]& ��w Dd h�X�\�V�VJU*h�`J]3_o WsZ�V�c �d \�S�X�d tjk�]^U*rmX1d tjk�\�`�U*VCk�V�d lsV�Z&tuSReFU4V�U6i U*WU*]3dsk�U&iui�\�V�c^h�lj`Jb�c-SC`�c^tjU�`�dmV�U&Zsi � h�l ]3c@S"b`�U*r `�d \�`v]^d \�i z%Uxw l�w^o �2% � � � > o �R]^]3U*h�U*` Z�]�w3o({4|(Ca^��� � " �p� � > oI�Rc^l c^`�Z�] ���\�c3k�tmU*h�` DdsV��k=dsV�Z&`�c3dshAo�{4|(Ca^s� � `�b�U&S�UDk�V�dsl V�Z&tuSAeFU*VJU9c^tjk�]^U*t U4h`�U&iCQ�_ X1d h�S�`�VJ\�X1`�c^h�lNZ ]@Z�V�lsUCi�Z&`�Z&Q�Z S�Ud�[�k�V�dsh�\�hTX1c-Z&`�c3dsh�Z&h�i lsV�Z�tmtuZ�VDV�\�]3U&S�w

� tuZ���dsVRk�VJd Q�]^U*t eCc^`�b#S"\TX�b;S"_�S"`�U4tuS�zpZ&h�i�Z�]@S"djeCc^`�b�`�b�U6X1dsl h�c^`�c3WUYtjd i U*]-S��DeCZ Sb�d&e `Jd�i�U*`�U4V�tjc^h�U�`�b�UaS"U*`�d&[CVJ\�]3U&S.`�b�Z&`�`�b�UaS�_�S�`�U*t \�S"U S1w � b�U*V�UaZ&V�U6tuZ&h�_uk�dSJS"c^Q�]3US"U*`�S d�[YVJ\�]3U&SjzOd�[YeCc@i�U*]^_:WsZ�VJ_�c^h�l S"c �4U&S6Z�h�i X1d tmk�]3U*r c3`�_��C`�bTZ�`mX1d \�]@iLc3tjk�]^U*taU*h�`N`�b�UtuZ�k�k�c3h�l c3h�ZEVJd \�lsb�]3_mU���\�c3WsZ�]^U*h�`,eCZ*_w

Page 36: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ������� ��������� � {*}

Db�d tuS ��_YZ&h�i'��Z&]3]3U.zJ{*|(h�C��Ak�V�d k�dxS"U&i6`�b�Z&`(S�U*`�SAd�[ VJ\�]3U&SAS�b�d \�]-i Q�U9[OdsV�ta\�]-Z&`�U&iR`Jb�Z�`56$-��$-56$��&�a�����m G 5R���3����$3� � d�[.`�b�U lsV�Z�tmtuZ�V4o `�b�Z&` c@S1o VJ\�]3U S `Jb�Z�` tjc3h�c3tjc(�*UY`�b�U d X*X�\�V��V�U*h�X�URd&[DS�k=U X1c-Z&]AX*ZsS"U&S�zOd VFU4r�X1U4k�`�c^d h�S���w �.d�e,U*WU*V4o�c^huZv`�Z S �uS"\�X�buZsSFtuZ�k�k�c3h�l � h�l ]3c@S"b`�U*r `6`�d S"ds\�h�i�S�o c^` c@S `�b�ds\�l b `j`Jb�Z�`ah�d S�\�X�b k�Z&V�S�c3tjdsh�c3ds\�S S�U*`ad�[YVJ\�]3U&S U4r�c@S"`�S `Jb�Z�`eFd \�]-i6U*]3c^tjc3h�Z&`�U,U*r�X�U*k�`�c^d h�S�Z�]3`Jd lsU*`�b�U4V�z Dds]3`Jb�U&Z�VJ`*o {*|a^0C���w � b�U4V�U1[OdsV�Uo`�b�URVJ\�]3U �OQ�ZsS"U&iZ�k�k�VJdZsX�b `JdLX1dsl h�c^`�c^WU tmd i�U*]3]^c3h�l 56�x��� S�k=U X1c [O_ S�d tjUueKZ _ d&[Yb�Z�hTi�]3c^h�l:U4r�X1U4k�`�c^d h�S�wDd \�]@in`�b�U*_�Q�U6b�Z�h�i ]3U&i�Q�_u`Jb�UaS�Z&tjU6S�_�S�`�U*t Z S�`�b�U6VJU*l \�]-Z�VNc3`�U4tuS1o�dsVvc@S�ZjS�U*k�Z�V�Z�`JUS"\�Q�S�_�S�`�U*t V�U��\�c3VJU&i �

q huZYk�Z�V�Z�]^]3U*] i�U*WU*]^d k�tjU4h�`4o*c3h WU&S"`Jc3lZ&`�dsV�S9d&[ V�U&Zsi�c3h�l6k�V�d X1U S�S"U S9c3hm`�b�U�U Z�V�]^_n{4|a^ ~ $ Sz y Z�VJd h�� &`JV�Z*e.S"dshAo.{*|a^0h � g dsV�S"`JU*V�� Db�Z&t Q�U*V�S1o,{*|a^ }�� h�d `JU&i:VJU&Z i�c^h�l�Q�U*b�Z*W c3d \�V�S`�b�Z&`YS"\�lsl U&S�`�U&i�`�b�U U*r c-S�`�U*h�X�U d�[,`�eFdmi�c@S"`�c^h�X1`.tjU&X�b�Z�h�c-S"t S [Od VNb�Z�h�i ]3c3h�ljV�U*ls\�]-Z&VYZ�hTiU*r�X�U*k�`�c^d haeFdsV�i�S�w �RdsV�tuZ&] Z i�\�]^`FVJU&Z i�U4V�S9e,U*V�U.[Od \�h�ij`Jd6`�Z"�UN]3d h�l U*V,`�d6V�U X1d lsh�c �*UNZ�hTik�V�dsh�d \�hTX1U # U4r�X1U4k�`�c^d h $&eFdsV�i�S"��`�b�Z&`9c@S1o eFd V�i�S9`Jb�Z�`Ki�c-i6h�ds`CX1dsh�[Od VJt `�d `Jb�U6z�Z S�S�\�tjU&i��S"k�U*]3]^c3h�l �pS�d \�hTi X1dsV�V�U S"k�d h�i U*h�X1U�V�\�]^U&SEd&[ �(h�l ]^c-S�bAw q ` eKZ SaZ�]@S"d:[Ods\�h�i `Jb�Z�` i�_�S�]3U*r c-Xk�Z�`Jc3U*h `�SRbTZ i#i�c-S�k�Z�V�Z�`�UaZ&Q�c3]^c3`Jc3U&SCc3h�VJU&Z i�c^h�luU*r�X1U*k�`Jc3d h;Z�h�i�V�U4l \�]@Z�V�e,d V�i�SEz $ Z�V�S"b�Z&]3]� �RU*eKX1d taQ�Uo�{4|a^&}��w

$ dsV�U U*W�c@i�U*h�X�U�d h#i�_�S"]^U*r c-X�k�Z�`Jc3U*h `�SCeCZsS k�V�U&S�U*h�`JU&i Q _ Dd ]^`�b�U&Z&V�`4o=eCb�d i�V�U*e `�b�Ui�c-S�k�Z�V�Z�`�U S�`�V�Z&h�i�SFd&[(U*tmk�c3VJc-X*Z&]�U*W c-i U*h�X1U.`�dsl U*`Jb�U*VFc^h�`Jd6Z&h U4r�k�]^c-X1c^`(k�VJd X1U&i�\�V�Z�]A`Jb�U*d VJ_d�[ V�U&Zsi�c3h�l Z�]^d \�i o ��h�d�eCh Z Sa`�b�U#i�\TZ�]�VJd \�`JU�`�b�U*dsV�_ z Dd ]^`�b�U Z�V�`4o {4|a^`C oY{*|(Cs~���w ��Sh�d `JU&iuZ�Q�d&WUo�Z&]3`�b�d \�lsbn`�b�U i \�Z�]AVJd \�`JUv`Jb�U*dsV�_jc@SCS"`�VJc-X1`J]3_aZ tjd i U*] d&[(b \�tuZ&hjV�U&Zsi�c3h�l�oc3`NX*Z�h#Q�UaS"U*U*h�lsU*h�U*V�Z�]^]3_�Z SYZjS�`�V�Z&`�U*ls_�d�[,\�S�c3h�ljVJ\�]3U S�Z�h�i�U*r�X1U*k�`Jc3dsh�S `Jdjc3tmk�]3U*tmU1h `Z tuZ�k�k�c3h�la`�ZsS � w � S"c3tmc3]-Z&VCV�\�]^U&S ��Z�hTi �%U4r�X1U4k�`�c^d h�SCtjd i�U*] b�ZsS�Z�]@S"djQ�U*U*h�k�V�d k�dxS"U&inQ _! c^h �U*V z�{4| |�{&��`JdjU*r k�]-Z&c3h�`�b�U6tuZ�k�k�c3h�lad�[� h�l ]3c@S"b�k�ZsS"`Y`�U4h�S"U&S�oAZ�hTi Q _ &b�Z�h ��SYZ�hTi&`*w`= dsb�huz�{4| |]& � `�d.U*r�k�]-Z�c^hYb�\�t Z�h X*Z�`JU*l dsV�_Y]3U Z�V�h�c3h�l�w &U*c@i�U*h Q�U*V�lYzJ{*| |���� Z&]-S�d�V�U*W c3U4e.SZ V�Z�h�lsU�d�[ X1d lsh�c3`Jc3WUC`�Z S ��S(c3haeCb�c-X�b6U*r k�]-Z&h�Z�`Jc3dsh�S(b�Z*WURQ�U*U*h6k�V�d k�dxS"U&ij\�S�c3h�lY`�b�U�i�\TZ�]V�d \�`�U�[Od VJtuZ�]^c-S"t;w

��� � � � ����� � ���

� b�U lsU*h�U*V�Z�]Di�\TZ�] V�d \�`�U6`�b�U*d VJ_nd�[ ��\�ZsS"c^V�U*ls\�]-Z&V�tuZ�k�k�c3h�lxSvzOeCb�c-X�b ! c^h �U*V*oA{4| | { oAb�Z SZ�]-S�d z%k�\�h�h�c3h�l ]3_��Y`�U4V�tjU&i�`�b�U ����3� ��� G �"� `�b�U*d VJ_=�Yk�dS�c3`�SE`Jb�Z�`6`Jb�U*V�U Z�V�U ��8 G �&�p������ ���

Page 37: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

{'& ������������ � � ����� � � � � ��� ����� �������O���

tjU&X�b�Z�h�c@S"tuSC[Od Vak�V�d X1U S�S"c^h�l#V�U*ls\�]-Z&VaZ�h�i U*r�X�U*k�`�c^d hLc^`�U*t S1wOj U4l \�]@Z�Vac3`�U4tuSYZ�V�Uuk�VJd��X1U&S�S�U&inW c-ZjZuS"U4`�d�[Kl U*h�U4V�Z�]�V�\�]^U&S1o eCb�c3]3U6U4r�X1U4k�`�c^d h�SR`JduS"\TX�b#V�\�]^U&SRta\�S"`.Q�UaS"U&Z&V�X�b�U&i[Od V.c3h�Z�h�c3h `�U*VJh�Z�] #!]3dd&� �O\�k $�`�Z&Q�]3Uxo�`�b�Z&`�X1dsh�`�Z�c^h�S `Jb�U t Z�k�k�c^h�l `�Z�VJl U*`�S [Od VNZ�]^] ��h�d&eChU*r�X�U*k�`�c^d hjc^`�U*t S c^hu`�b�U i�dstuZ�c^hAw

�NS Z�h U*r�Z�tmk�]3Uo q eCc^]3]Ki�U&S�X�V�c3Q�Uad h�Uud&[.`�b�UjQ�U&S�` ��h�d�eCh#[Od V�ta\�]@Z�`�c^d h�SYd�[NZ�i�\TZ�]V�d \�`�UY`�b�U4d V�_xo�`�bTZ�`Ni�U&S�X�V�c3Q�U&iaQ�_ Dd ]^`�b�U&Z&V�`YzJ{*|a^0C�o {*|�C ~�� Z�h�i Dd ]^`�b�U Z�V�`CU4`.Z�]pw z�{4| | }�`�d6tjd i�U4] b \�tuZ�hmV�U&Zsi�c3h�l6d&[(eCVJc3`J`�U*hu`�U4r�`4w � b�U�[O\�h�X�`�c3dsh�Z�] Z&V�X�b�c3`JU&X1`J\�V�U.c-SFc^]3]3\TS"`�V�Z�`JU&ic3h g c3l \�V�U�� w3{sw � b�U,`�U*VJtjc3h�ds]3dsl _�\�S�U&i c-S S"k�U&X�c � X(`�dNeFd V�i �Ok�V�dsh�\�hTX1c-Z&`�c3dshAo Q�\�`(`�b�U,Q�Z S�c-Xi�\�Z�]^c3`�_nd&[C`Jb�U6tjd i�U*]�c-S���\�c3`�UaX�]3U&Z&V*w � b�U4V�UaZ�VJU `�e,d VJd \�`JU&SR[Od VYk�VJd h�ds\�h�X1c^h�lne,d V�i�S1w� b�U6V�ds\�`�Uad h�`Jb�U6]3U1[O`Nc-S � h�d&eChLZsS�`�b�U �3�J�s$-�� � VJd \�`JUoAQ�U&X*Z�\TS"U6c3`Nb�d ]@i�SYZ �^���s$- G � o d Vi�c-X1`Jc3dsh�Z�VJ_o(d�[NeFdsV�iLU*h `�V�c^U&S1o c3hLeCb�c-X�bL`�b�Umk�V�dsh�\�hTX1c-Z&`�c3dsh d�[ Z ��h�d&eCh eFdsV�i X*Z&h Q�U]3dd&�U i \�kAw��(r�X1U4k�`�c^d hueFdsV�i�S.X*Z�hudsh�]3_jQ�U k�V�dsh�d \�hTX1U&i W c-ZY`�b�c@S VJd \�`JUw

q hj[�Z X�`*o Z�]3] >�� G 8(� �(h�l ]^c-S�bneFdsV�i�S.X1ds\�]-iuQ=UYk�VJd h�ds\�h�X1U inQ�_uZ6]3U4r�c@X*Z�] tjU&X�b�Z�h�c@S"t�fd h�U.S�c3tjk�]^_YtjU*tjdsV�c ��U&S `Jb�U.S"k�U*]^]3c3h�lYZ�h�iaS"ds\�h�i6d�[ U&Z X�b �(h�l ]^c-S"b6e,d V�i o Z�h�i6]3dd ��SD`�b�U*t\�kneCb�U4hn`�b�U*_�Z�V�U U*h�X1ds\�h `�U*VJU&i w �Rd&eFU*WU*V4o�`Jb�c-SC`�U&X�b�h�c ��\�U�eFds\�]-iuh�d `�e,d V�� [OdsVRh�d�WU4]� G ��8 G �J��� S�\�X�b#Z S 5� �B/ Z�hTi � L��� oAZsS�`�b�U*VJU b�ZsS�Q=U4U*h�h�dud k�k�dsV�`�\�h�c3`�_n`JdutjU*tjdsV�c ��U`�b�U*c^VCS�d \�h�i�S1w

� d.b�Z�h�i ]3UDh�d h eFdsV�i�S�oZ.S"U&X1dsh�ivVJd \�`JUDc-S V�U ��\�c^V�U&i w � b�U9VJc3lsb�` �%b�Z&h�ivVJd \�`JU�z ��h�d&eCh Z S`�b�U � G � �p�3���s$-�� � VJd \�`JU �NX1d h `�Z&c3h�SRlsU*h�U*V�Z�] ��J�1������5 � �3��� G �=��5 �a G �1������� G ��������1� z N ! C�V�\�]^U&S1o eCb�c-X�b�Z�V�U Z&k�k�]3c^U&ij`�daZ&hnd VJ`�b�dsl V�Z�k�b�c@X*Z�] U*h `�c^`"_a`�d6k�V�d i�\�X�U6Z6k�V�dsh�\�hTX1c-Z&`�c3dshAw

Dds]3`Jb�U&Z�VJ` $!S i�\TZ�].V�d \�`�Un`Jb�U*dsV�_ d�[Yb \�tuZ&h V�U&Zsi�c3h�l �pZ&]3ds\�i eCZsS0[OdsV�ta\�]-Z&`�U&i:c^h VJU �S"k�d h�S�U6`�djQ�U*bTZ W c3ds\�V�Z&]Di�Z&`�Z dsh�b�\�t Z�huV�U&Zsi�c3h�l�o Q�d `Jbn[Od V�h�d V�t Z�] V�U&Zsi�U*V�SYz y Z&V�dshO�&`�V�Z e.S�d hAo {*|�^`h � g d V�S"`�U4V�� Db�Z&t Q�U*V�S1o�{4|a^ }��KZ�h�iji _�S�]3U*r c-X*S,z $ Z�V�S"b�Z&]3] � �RU*eKX1d taQ�Uo{*|a^ }���w � b�U;i�\�Z�]NV�d \�`�Un`Jb�U*dsV�_ c-SaZ�Q�]^Un`Jd:U*r k�]@Z�c3h k�b�U*h�d tmU*h�Z#S"\�X�b Z S ��� G � G � G �x$ ��� �(���*���3���s$-� zOeCb�U*VJU `�b�U6Z�Q�c3]3c^`�_j`�djk�V�d h�d \�h�X�U6h�d h eFdsV�i�SRc@SRZ&k�k�Z&V�U*h `�]^_ c^tjk�Z&c3V�U iji�\�U`�dj`Jb�U6]3dxS�SRd&[C`�b�U6h�d h��O]3U4r�c@X*Z�],z%VJ\�]3U �,V�ds\�`�Us�.Z�h�i �4� �324�1�6���*���3���s$-� z%eCb�U*VJU6`�b�U0Z�Q�c^]3c^`"_`�dLk�VJd h�ds\�h�X1U�U4r�X1U4k�`�c^d h eFdsV�i�S c@SEc^tjk�Z&c3V�U i i \�Un`JdL`�b�U�]3dxS�S d&[ `Jb�Un]^U*r c-X*Z&]FV�ds\�`�Us��wg \�V�`�b�U*V�tjdsV�Uo�c^`Rd � U*V�SYZ�h#ZsX*X1ds\�h�`0z Dd ]^`�b�U Z�V�`4o({*|�^`C�Rd&[,eCb�_�V�U&Zsi�U*V�SC`�Z �U6]3dsh�l U*VN`�dk�V�dsh�d \�hTX1U.Z�h�i6V�U X1d lsh�c �*U,U*r�X1U*k�`Jc3d hYe,d V�i�S��`�b�c@S U � U&X1` U&S�`�Z�Q�]3c-S�b�U&S�oZ X*X�d V�i c3h�l�`Jd'Dd ]3` �b�U&Z�VJ`*o `�b�U���kTS"_�X�b�ds]3dsl c-X4Z�]AV�U Z�]3c^`�_���d�[�`�b�U i c-S"`Jc3h�X�`�c3dshjQ�U*`�eFU*U4hjV�U*ls\�]-Z&V.Z�h�ijU*r�X1U*k�`�c3dsh

Page 38: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ������� ��������� � { %

visual word-detectors

grapheme-phonemerule system

phoneme system

phonological lexicon

semantic system

speech

visual feature detectors

letter detectors

print

g c3ls\�V�UR��w^{ f � b�U0i�\�Z&]AV�d \�`�UYtjd i�U*] d�[DVJU&Z i c3h�l�w���i�Z�k�`�U&i [OV�dst g c3ls\�V�UF�6d�[ Dd ]3`Jb�U&Z&V�`U*`.Z�]�wAz�{*|s| }��w

Page 39: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

{Dh ������������ � � ����� � � � � ��� ����� �������O���

eFd V�i�SYz Dd ]^`�b�U Z�V�`4oA{*|�^`C���wP.h�Umd�[.`�b�UjS�`�V�dsh�l U S"`6U*W c-i�U4h�`Jc-Z�] S"\�k�k�dsV�`�Sv[OdsV `Jb�Uji \�Z�],V�d \�`�Uj`Jb�U*d VJ_:c@SYX1]-Z&c3tjU&i

`�dnQ�Uj`Jb�UjU*r c-S�`�U*hTX1U6d�[ � G � /1�3� �$ ��� G 4$-� �p$ G ��� z ! c3h �U*V4oD{*| | {��F`Jb�U&S�U eCc^]3]DQ�Uui�c-SJX1\�SJS"U&ic3h�tjdsV�Uai�U*`�Z�c^](c3h%Db�Z&k�`�U4V & ��w?�Rds\�Q�]3Umi�c@S�S"d X�c-Z�`Jc3dsh�SYZ�V�UmS�Z&c-i�`�dud X*X1\�VvcB[,d h�UaV�ds\�`�Uc-S i�Z�tuZ&l U&iLeCb�c^]3Ua`�b�Uud `Jb�U*V6c@Sv]3U�[O` V�U4]-Z�`Jc3WU*]^_nc^h�`�Z X1`4o(Z�hTi W c-X1UaWU*V�SJZ�w � b�U�i�_�S"]^U*r �c-Z S.i�U&SJX1V�c^Q�U&inZ&Q=d&WU0X*Z�h�Q=U U*r k�]-Z&c3h�U&ijQ _ub�_ k�d `�b�U&S"c �*c3h�lmZai�c-SJS"d X1c@Z�`�c^d h�Q�U*`�eFU4U*hu`�b�U]3U*r c-X*Z&] Z�h�iuh�d h��O]3U4r�c@X*Z�]AVJd \�`JU&S1w � b�UY[�Z X1`C`Jb�Z�`NS"\TX�b�i�c@S�S"d X�c-Z�`Jc3dsh�SRX4Z�hud X*X1\�VNS"\�l l U S"`�SS"`�VJd h�ls]3_j`Jb�Z�`.`�b�Uvb _ k=ds`�b�U S"c-SFd&[D`�eFdaS�U*k�Z�V�Z�`JU V�ds\�`�U SFc-SCZ6k�b�_�S"c@X*Z�] V�U&Z&]3c^`"_xw

�.d `ad h�]^_Lc3h `�b�U �TU*]-iLd�[ b�\�t Z�h tjd i�U*]^]3c^h�lnb�ZsSE`Jb�U�i�\�Z&]RVJd \�`JU�Z�k�k�V�dxZ X�b Q�U*U*hk=dsk�\�]@Z�VR[OdsVRc^tjk�]3U4t U*h `�cBh�l ��\TZ S"c^V�U*ls\�]-Z&VRt Z�k�k�c^h�lS�w q h�i�U*k�U*hTi�U*h `�]3_ad�[,`Jb�U tjd i U*]3]^c3h�leFd V��#z $ w Dd ]3`Jb�U&Z&V�`*o�k�U*V�S�d h�Z&]DX1dstjt \�h�c-X�Z�`Jc3d h o�= \�h�U0} ~n{4| |s}���o V�U&S�U&Z�V�X�b�U4V�SCeFd V���c^h�ld h#`�U&X�b�h�ds]3d lsc-X*Z&] `JU*r `���S"k�U*U&X�b�S�_�S�`�U*tuSYzpS�\�X�b#Z S $�q � Z&] ��Z�h�iO� � D`�Z&] ���.S"U4`�`�]^U&ind h Zi�\�Z�].V�ds\�`�Uj[OdsV�ta\�]-Z&`�c3dshAfjZ#S"U4` d&[Yl U*h�U*V�Z&]Ck�V�dsh�\�hTX1c-Z&`�c3dsh V�\�]^U&S6S"\�k�k�]3U*tmU*h�`JU&i:Q _ Zz%]3c^`�U*V�Z�]O�(]3dd ��\�kn`�Z&Q�]3UYd&[(U*r�X1U*k�`�c3dshjeFdsV�i�S�w

� b�U*V�U0Z�V�Uxo�b�d&eFU*WU*V4o�c^tjk�d V�`�Z�h `.i�c � U*VJU*h�X1U S1w � b�U ��V�S"`�c@SFk�V�d X�U&i�\�V�Z�]pw q h $�q � Z&] � o`�b�U�]3dd&� \�k `�Z&Q�]3U�c-SjX1dsh�S"\�]3`�U i ��V�S�`*oCeCc3`Jb l U4h�U*V�Z&]�k�VJd h \�h�X1c@Z�`�c^d h VJ\�]3U&S6d h�]3_ Q�U*c^h�lZ�k�k�]^c3U&i6c [ `Jb�U.eFd V�i c-SDh�d `D[Od \�hTi w q h Dd ]^`�b�U&Z&V�` $ SFi \�Z�] V�d \�`�U�tjd i U*]poQ�d `Jb `Jb�U.]3U*r c-X1dshZ�h�i `Jb�UCV�\�]^U&S Z�V�U.X�d h�S�\�]3`JU&i X1dsh�X1\�VJV�U*h `�]^_�[Od V � �^� e,d V�i�S1w � S�U&X1dsh�i i�c � U*V�U*hTX1UCX1dsh�X1U*VJh�S`�b�U,`"_ k�UFd&[ e,d V�i�S(S"`Jd VJU&i c3h `�b�U,]3U*r c-X1dshAw q h $�q � Z&] � o�dsh�]3_YU*r�X1U*k�`�c3dshYeFd V�i�S(Z&V�U.S"`Jd VJU&i oZ S V�U4l \�]@Z�V�S X*Z�h Q�Ujb�Z&h�i�]^U&i:Q _:`Jb�UjV�\�]3UmS"U*`4w q hL`�b�U i�\�Z�],V�ds\�`�Uutjd i�U4]9d&[.V�U&Zsi�c3h�l�o� �3� � h�d&eCh�eFd V�i�S.Z�V�UaS�`�dsV�U&iuc3hn`Jb�U ]^U*r c-X1dshAw � b�c-S�X1dsh ��ls\�V�Z&`�c3dsh�eFds\�]-i�Z�k�k�U&Z&V�`�djQ�UX1d tjk�\�`�Z&`�c3dsh�Z�]^]3_6VJU&i�\�h�i�Z�h `*o�Q�\�`Cc^`Cc-SFVJU���\�c3V�U i `�d6U*r k�]@Z�c3h X1U*V�`�Z�c^hnZsS"k�U&X1`�S d&[(b \�tuZ&hV�U&Zsi�c3h�l Q�U*b�Z*W c3ds\�V�zpS�\�X�b Z S k�b�d h�ds]3dsl c-X4Z�] Z�h�i S"\�V"[�Z X�U#i�_�S�]3U*r c-Z � Dd ]^`�b�U&Z&V�`uU*`uZ&]pw^o{*| |s}���w q h�X1c@i�U*h `�Z&]3]3_xo�d `Jb�U*V�WU4V�S"c^d h�SCd�[,`Jb�U6i�\TZ�](VJd \�`JU6`�b�U*dsV�_ z ! c3h �U4V*oA{*|s|�{&��i djh�d `V�U��\�c3VJU�V�U4l \�]@Z�VCc3`JU*tuS(`�daQ�U S"`�dsV�U&iuc3hu`�b�Uv]^dd&� \�kn`�Z�Q�]^Uw

� b�U [O\�h�i�Z�tmU*h�`�Z�] k�V�dsk=U4V�`�c^U&SFd�[9i�\�Z�]AVJd \�`JU `Jb�U*d VJc3U&S,Z�VJU b�U*hTX1U6f

� � i�c-S�`�c3hTX1`�c^d hjc@SFtuZ i�UNQ=U4`"e,U*U*hjVJU*l \�]-Z�VNZ�hTi U*r�X1U*k�`Jc3dshjc3`JU*tuS��

� � eFdmS"U*kTZ�V�Z&`�U6c^h�`JU*V�h�Z&] tjU X�b�Z&h�c-S�tuS [Od V.b�Z�hTi�]3c^h�ljV�U4l \�]@Z�VNZ�h�iuU*r�X�U*k�`�c^d huc3`JU*tuSU*r c-S"`4w

�.\�Z�]DV�ds\�`�Ua`�b�U*d VJc3U&S�X4Z�h#Q=UmS"U4U*hLZsSYZ�h ���B�/ G ��� ��$ G � d�[C`Jb�UaV�\�]^U �%QTZ S"U i:Z&k�k�V�dxZ X�bAo

Page 40: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � ���� � ������ � �O��� � ��� � {]^

`�b�Z&`�S�k=U X1c [O_ab�d&e `�b�U S�_�S�`�U*t b�Z&h�i�]3U S ����1�p���p$ G �� `Jd6`�b�UYVJ\�]3U&SCS�`�dsV�U&iuQ�_a`�b�U S�_�S�`�U*t�w� c^`�b�`Jb�UaS"\�X4X1U&S�SCd�[K`�b�Uai \�Z�](VJd \�`JU6`�b�U4d V�_�c3h;X1d lsh�c3`Jc3WU tmd i�U*]3]^c3h�l�o�Z�h�i�`�b�U6\�S"U

d�[ S"c3tmc3]-Z&VCi�\TZ�]AV�ds\�`�UYtjU X�b�Z&h�c-S�tuS(c3hu`�U X�b�h�d ]3dsl c@X*Z�] Z�k�k�]^c-X*Z&`�c^d h�S�o�`�b�UYk�dS�c3`�c^d h�d�[�`�b�Ui�\�Z�]AVJd \�`JU `Jb�U*d VJ_uS"U4U*tjU&i6\�h�ZsS�S�Z&c3]@Z�Q�]^Uf

q h�i�U*U&i o(d h�Uutjc^l b `vQ�U�`�U*tjk�`�U&i�`�d#ZsS � b�d&e U4]-S"U X1d \�]@iLh�d&WU*]Fe,d V�i�SEQ�UV�U&Zsi c [ h�d `CW c-ZvVJ\�]3U S1o Z�h�ijb�d&e U*]-S�UYX1ds\�]-i U4r�X1U4k�`�c^d haeFd V�i�SFQ�U�V�U Z ijc [ h�ds`\�S"c^h�l6eFdsV�i ��S"k�U&X�c � X ��h�d&eC]^U&i�l U ��zMjCdS�U*h Q=U4V�l�oA{4|(C�C�o�kAwR{&�

q hj[�Z X�`*o�Z SF[�Z�VNZ SCV�U Z i�c^h�l `JU*r `CZ�]^d \�iuc-SCX1dsh�X1U*VJh�U&i o�`Jb�U S"\�X4X1U&S�SFd&[D`�b�U i \�Z�] V�ds\�`�U`�b�U*dsV�_6k�VJd tjk�`�U&i Dds]3`�b�U&Z�VJ`9`Jd tuZ �UF`Jb�U�S�`�VJd h�laX1]@Z�c^t `�bTZ�`*oh�ds`Fdsh�]3_ai�dYb \�tuZ&h�S(\�S"UZvi \�Z�]�VJd \�`JUR`Jd�V�U Z i6eFd V�i�SDZ�]^d \�i oQ�\�`DZ�]@S"dY`�b�Z&` ���� S"_�S"`JU*t [OdsV(V�U Z i�c^h�lYeFd V�i�S(eFds\�]-i��� � � $-��� ZYi�\�Z&]�V�d \�`�UNZ�V�X�b�c^`�U&X1`J\�V�U,`�d Z X�b�c^U*WUCS ��c^]3]3U ivV�U Z i�c^h�lYk=U4V"[Od VJtuZ�hTX1UYz Dds]3`�b�U&Z�VJ`*o{*| |`&Z�@�&w

��� � ��� � � ��� �� �� ��� � � ���

�RU&S"k�c3`�U c3`�S�S"\�X4X1U&S�SNZ�`YU*r k�]-Z&c3h�c^h�ljZaeCc-i�U6V�Z�h�lsU6d�[CU4tjk�c3VJc-X*Z&] dsQ�S"U*VJWsZ�`�c^d h�S�oA`�b�Uai�\TZ�]V�d \�`�Uj`Jb�U*d VJ_:bTZ S h�ds`6Q=U4U*hLeCc3`Jb�d \�`6c3`�S X1V�c^`�c@X*S1w &k�U&X1c(� XjX1VJc3`�c@X1c-S�tuSCd�[N`�b�c@S Z X4X1d \�h `b�Z*WU Q�U*U*h�V�Z�c-S�U&ind&WU*V�`Jb�U6_U&Z�V�S1oAZ&h�i q eCc3]3] h�d&e i c-S�X�\�S�S�ZuS�U*]3U&X�`�c3dshnd&[F`Jb�U&S�Uw � b�c-Si�c-SJX1\�S�S�c3dshneCc3]^]AQ�Uv[Od ]^]3d&eFU i Q _uZjS"b�d V�`NZ�k�k�V�Z&c-S�Z&](d�[,b�d&e VJU&X1U*h `CWU*V�S"c3dsh�SCd�[D`Jb�U6i�\TZ�]V�d \�`�UY`�b�U4d V�_mb�Z*WU Z&`�`JU*tjk�`JU&i `�daZsi�i�VJU&S�SC`�b�U S"U X1V�c^`�c@X1c-S�tuS1w

g c3V�S�`�]^_o `�b�U�i�\TZ�]�V�ds\�`�UNZ X*X�d \�h `Dd�[AVJU&Z i c3h�l0X*Z�h�h�d `,Z X*X�d \�h `([Od V G ��4$ ���"���� � � �Y�J1�-�z N.]3\�S�b �d�o.{*|�^&|�6c3h k�VJd h \�h�X1c@Z�`�c^d h ]-Z&`�U*hTX1c3U&S � w � b�Z&` c@S1oDc3` b�Z S6Q�U*U*h i U*tjd hTS"`�V�Z�`JU&i`�b�Z&` VJU*l \�]@Z�Vac3h�X�d h�S�c-S"`JU*h `6eFd V�i�Suz%cpw Uw3o(VJU*l \�]-Z�VaeFdsV�i�S6`�bTZ�`uZ&V�U�S�k�U*]3]^U&i S"c3tmc3]-Z&V�]^_�`�dU*r�X�U*k�`�c^d h�e,d V�i�S1o(S�\�X�bLZsS �� � zpS"c^tjc3]@Z�V.`�d E�� �> ���N`�Z �U6]3d h�l U*VY`�d�k�V�dsh�d \�h�X1Ua`�b�Z&hV�U*ls\�]-Z&VYX1d hTS"c-S�`�U*h `�e,d V�i�SEz�S"\�X�b#Z S � �5.i/ o eCb�c@X�b�b�Z*WU6h�duS"c^tjc3]@Z�V.U*r�X1U*k�`Jc3d h�eFdsV�i�S���w� b�U�i�\TZ�]�VJd \�`JU�`�b�U*dsV�_o,eCb�c-X�b dsh�]3_ V�U X1d lsh�c �*U SE`Jb�UnVJU*l \�]@Z�V �*U*r�X1U*k�`Jc3dsh i�c@S"`�c^h�X1`Jc3d h oX*Z�h�h�d `.U*r�k�]-Z�c^hj`�b�c-SFU � U&X1`4w

! RG<,/$'=9243M&'$ =;3M0 0+36(*DH$-=;36$ =92�3<D�_I367;)#24D0-F;)-= 3[0-$'&'G<798O)+,*3M( A (/7$-=92[=9G<1;2RG6^��-19&'G6_<GI5�(/798?3HD�(/0-19&'G�G6^ �U � b RGI,/$-=92436&-$4:>1;2@&-0'G<7;36, )+GIAVA�F979(*)@36$-(/GI7 :������IF>792 ���������9)+(/$'24DVa[(/$'=�1 2@&'AV( 0-0'(/GI7 Z@b��� 0-(/A (/,*36& 2��P24)+$H=;360[Q 2@2@7 ( D%2@7�$'(YX;24DV(/7 1;3M0'$ �W$-2@790'2 8I2@792�&S36$-(/GI7 Uc"�2@(*D�2@7�Q 2@&'8 : ������<Z@b

Page 41: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

{DC ������������ � � ����� � � � � ��� ����� �������O���

� S�U&X1dsh�i�X1V�c^`�c@X1c-S�t X1d hTX1U*V�hTSRk�V�dsk�U*V�`Jc3U&SRd&[,`�b�U6k�\�`�Z�`Jc3WU0S"U*`�d&[CU*r�X1U*k�`�c3dshne,d V�i�S1w� b�U:c@i�U&Z:`Jb�Z�`uU*r�X1U*k�`�c3dsh�Z�]NtuZ�k�k�c3h�lxSjZ�VJULS�`�d VJU&i Q�_ V�d `JU:c@SuX1d tjkTZ�`�c^Q�]3U�eCc3`Jb `�b�Uh�d `Jc3d h d�[.U*r�X1U*k�`Jc3dsh�SYZ S b�c^l b�]^_�c3V�VJU*l \�]-Z�V4o(S�c3h�ls\�]-Z&V eFdsV�i�Sjz�S"\�X�b Z S ���9 ����9 oAd V `�b�UtuZ�k�k�c3h�l + �����<. ��o�Q�\�` h�d ` eCc3`�bY`Jb�UFdsQ�S"U*VJWsZ�`�c^d h `�b�Z&` U*r�X1U*k�`�c3dsh�S `�b�U*tuS"U4]3WU4S=Zsi�tjc^`d�[Ct Z�h _LzpS�\�Q ��V�U*ls\�]-Z&V�c3`Jc3U&S�w � b�Umi�\�Z&]DV�d \�`�UuZsX*X1d \�h�` X*Z&h�h�d ` U*r k�]-Z&c3h�eCb _�d h�U'��h�i�SX1]3\�S�`�U*V�S(d�[�S"c^tjc3]@Z�V(t Z�k�k�c^h�lSDS�\�X�b Z SRzOc3hj`Jb�U.k�Z S�`C`�U*h�S�U � .D,���� � .D� ��� ��`,���� � �]� ��� oZ�h�i .DE5�`,��5� �F. E5�`� ��� z ! c3h �U*V4o {4| |�{&��w

� `Jb�c3V�i X�V�c3`Jc-X1c@S"t X1dsh�X1U*VJh�S `�b�UR`�_ k=UCd&[AU*VJV�dsV�S(k�U*d k�]^URt Z"�UFeCb�U*h t Z�k�k�c^h�l�e,d V�i�S1w� b�URdsh�]3_6U4V�V�dsV�SD`�b�Z&`F`�b�U�i�\TZ�] VJd \�`JUR`Jb�U*dsV�_6eFds\�]-iak�V�U&i c-X1`DZ&V�U�`Jb�dS�UReCb�U*V�UNZvlsU*h�U*V�Z�]V�\�]^U6c-S�tjc-S�`�Z �U*h�]3_ Z�k�k�]^c3U&in`Jd�Z�hLU*r�X1U*k�`�c3dsh�eFdsV�i z &U*c@i�U*h Q�U*V�l�o({*|s|(��� � [Od V U*r�Z&tjk�]^Uo���/ Q�U*c3h�l�tuZ�k�k�U&i�`�d ��L/` � w �Rd&eFU*WU*V4o Z eCc-i U V�Z�h�lsU d&[.tuZ�k�k�c3h�luU*VJV�dsV�S6Z X�`�\�Z&]3]3_d X*X1\�VY`�bTZ�`YS�b�d&e `�b�U6dsk�k�dS"c^`�UaU � U&X1`4fRV�U4l \�]@Z�VYeFdsV�i�S�Q�U*c3h�l t Z�k�k�U&i�ZsS cB[,`�b�U*_�eFU*VJUU*r�X�U*k�`�c^d hje,d V�i�S1w ��S9U4r�Z&tjk�]3U S1o X�b�c3]-i V�U*huS�d tjU4`�c3tmU*S(l U4h�U*V�Z&`�UYU*VJV�d h�U*d \�SFU4r�X1U4k�`�c^d h�Z&]k�Z S�`9`JU*h�S�UCtuZ�k�k�c3h�lxSFz%Uw l�w^o ��93, ��� ����9)� ��� ��o Z&h�iEh�d�WU4]�e,d V�i�S(Z�VJU�S�d tjU*`Jc3tjU S=c3h ��U&X1`JU&iQ�_uZsi�\�]^`�SFc3h�Z&h # U4r�X1U4k�`�c^d h�Z&] $tuZ�h�h�U*V�zOUw l�w3o .DG593,���� �R.DG59������ � ! c3h �U4V*o�{*|s|�{���w

q h6VJU&S"k�d hTS"U.`�dY`�b�U S"U.X1VJc3`�c@X1c-S�tuS1o*c^tjk�d VJ`�Z�h `(tjd i c � X*Z&`�c^d h�S bTZ WU,V�U&X�U*h�`J]3_YQ�U*U*h6k�VJd��k=dxS"U&i#`�d�i \�Z�]DV�ds\�`�Ua`�b�U*d VJc3U&S�d�[.kTZ S"`Y`JU*h�S"Ual U4h�U*V�Z&`�c^d h z ! c^h �U*V4o({*|s|�{�� Z&h�i:VJU&Z i�c^h�lZ�]3ds\�i z Dd ]^`�b�U Z�V�`YU*` Z�]pw^o({*|s| }��w q h�U&S�S�U*h�X1Uo `�b�U6`Jb�U*d VJU*`�c@X*Z�]�tjd i�c �=X*Z�`Jc3d hTSRk�V�dsk�dS"U ic3hL`Jb�U&S"Umk�Z�k�U*V�S6Z�tjds\�h�`Y`Jd#Z�h Z�Q�Z&h�i�dsh�tjU*h ` d&[.`�b�Ujh�d `�c^d h d�[ Z ]^dd&� �%\�k `�Z&Q�]3Ua[Od Vb�Z�h�i ]3c3h�l U*r�X1U*k�`�c3dsh�S1o�c^tjk�]^U*t U�h `�c3h�lvc^h�S"`JU&Z i�S"_�S"`JU*tuSF`�bTZ�`.\�S"U ����� G 4$-� �p$-I�� 5 ��5 G �1$%���[Od V.S"\TX�bueFdsV�i�SYz ! c^h �U*V*o {*|s|�{���w

�.U*WU*V�`Jb�U*]^U&S�S�o i�U S"k�c^`�UCV�U X1U*h `(tjd i�c(� X*Z�`Jc3dsh�S1o `Jb�UNi�\�Z�]�VJd \�`JU�`�b�U4d V�_0S"`Jc3]3]�tuZ�c^h�`�Z�c3hTS`�b�Z&` b \�tuZ&h�SE\TS"ULz�Z�h�i h�U*U&i=�Y`�eFd i�c@S"`�c^h�X1`atjU&X�b�Z�h�c-S"tmS [OdsV t Z�k�k�c^h�l#`"e,dLi c-S"`Jc3h�X�`X1]-ZsS�S"U S9d�[ e,d V�i�S1f(VJU*l \�]@Z�V�SFZ�hTi U4r�X1U4k�`�c^d h�S�w q hj`�b�U [Ods]3]3d&eCc^h�l6S�U&X1`�c^d hAo q eCc3]^]�V�U*W c3U*e Z&hZ�]3`JU*V�hTZ�`�c^WU `Jb�U*d VJ_u`�b�Z&`vk�V�d k�dxS"U&S�c3hTS"`�U Z i�`�b�Z&`�h�d�S"\�X�b�i c-S"`Jc3h�X�`�c3dsh�c-SCV�U��\�c^V�U&i o Z�hTi`�b�Z&`6Z�]^]Fc^`�U*tuSNX*Z�hLQ�Ujt Z�k�k�U&i�Q�_#`�b�Ujd h�Um\�h�c [OdsV�t tjU X�b�Z&h�c-S�t�f�`�b�U G �����J1�p$ G ��$ ���tjd i�U*] d�[ ��\�ZsS"c^V�U*ls\�]-Z&VRtuZ&k�k�c^h�lS�w

Page 42: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����� �

� � � � � � � � �� � � � � � � ����� � �

����� ��� � � ���� ���� ��

q ha`�b�c-SDX�bTZ�k�`JU*V q VJU*W�c^U*e Z�h�\�taQ�U*V(d&[ X1dsh�h�U&X1`Jc3dsh�c-S�`9tmd i�U*]-S `�b�Z&`9bTZ WU.Q�U*U*hak�V�dsk�dS"U iZ S�Z&]3`�U4V�h�Z&`�c3WU SF`�da`�b�U0i�\�Z�] V�ds\�`�U `�b�U4d V�_xw y ZsS"c@X*Z�]^]3_o�X1d h�h�U&X1`�c^d h�c@S"`NZ�k�k�V�dZsX�b�U&S k�dxS"c3``�b�Z&`F`�b�U*V�U�c@S � G [O\�h�i�Z�tmU*h�`�Z�] i�c@S"`�c^h�X1`Jc3d haQ�U*`�eFU*U4hjV�U*ls\�]-Z&VCZ&h�ijU*r�X�U*k�`�c^d hac3`JU*tuS(Z&h�i ob�U*h�X1Uxo=`Jb�Z�`Y`�b�U*V�U c-SRh�duh�U4U&i [OdsVv`�e,djc3h `�U*VJh�Z�] tjU&X�b�Z&h�c-S�tjS"��d h�Ua\�h�c(��U&i tmU&X�bTZ�h�c@S"tX*Z�huc3tmk�]3U*taU*h `(`�b�U �\�ZsS"c3VJU*l \�]-Z�VCt Z�k�k�c^h�l [Od V.Z&]3]Ac^`�U*tuS�w

� b�UR[Od X1\�SFd&[ `�b�c@SFi�c@S�X1\�SJS"c^d hjc@S1oc3hj`Jb�U ��V�S"`,c3h�S�`�Z�hTX1Uo�h�d `Fdshj`�b�U�c-SJS"\�U�d&[ eCb�U*`Jb�U*VX1d h�h�U&X1`�c^d h�c@S"`�h�U4`"e,d V���Snk�VJd&W�c@i�U Z k�]@Z�\�S�c3Q�]^U ��� � �� G � G �$-�� � tjd i�U*]6d&[ �\�Z S�c3V�U4l \�]@Z�VtuZ�k�k�c3h�lxST�1osQ�\�`(V�Z�`�b�U*V(eCb�U*`Jb�U*VDX�d h�h�U X1`�c^d h�c@S"` h�U*`�eFdsV ��S Z&V�U.X*Z&k�Z�Q�]^UCd�[ c3tmk�]3U*taU*h `�cBh�lS"\�X�b6tuZ�k�k�c3h�lxS � ��� �3� ��`�bTZ�`Dc-S�o eCb�U*`Jb�U*V(`Jb�U*_ Z�VJU.Z�Q�]^UC`�d Z�`J`�Z�c^haZ�]3U*WU*]d&[ k=U4V"[Od VJtuZ�hTX1UX1d tjkTZ�V�Z&Q�]3UN`�da`�b�Z&`Cd�[,S ��c^]3]3U i b�\�tuZ�h�S�w

q X�c3`�UYU*r�Z�tmk�]3U&S([OV�dst `Jb�U kTZ S"` �%`JU*h�S�UaZ�h�inVJU&Z i�c^h�l���Z�]^d \�in]^c3`JU*V�Z&`�\�VJUv`JdjS�b�d&e `�b�Z&`*oc3h�c^`�c-Z&]�[�Z�c^]3\�VJU&S h�ds`�eCc3`�bTS"`�Z&h�i�c^h�l�o�`Jb�U*_ ���� Z&Q�]3U.`�d0i�d S"d�w � b�c@S ��h�i�c^h�l k�dS�U&SFZ S"c^l h�c(� �X*Z�h `D`�b�VJU&Z�`,`�d6`�b�U�i�\TZ�] VJd \�`JU�`�b�U*d VJ_ Q�U&X*Z&\�S"UNc3`DU&S"`�Z�Q�]^c-S�b�U&S9`Jb�U ����� G �"� �4��� *$%���� � d�[`�b�U X1dsh�h�U&X1`Jc3dsh�c-S�`CZ�k�k�V�dxZ X�bAo�Z�h�i�i�U*tjdsh�S"`JV�Z&`�U&SD`�b�Z&`R`Jb�U*V�UNc-S1o�i�U&S�k�c3`JUvU Z�V�]^c3U*V,X1]@Z�c^tuS1oZ e,d V �sZ&Q�]3U;Z�]3`JU*V�hTZ�`�c^WUj`�d#`�b�Uni \�Z�]^c-S"`mZ�V�X�b�c3`�U X1`�\�VJU [Od Vac3tmk�]3U*taU�h�`Jc3h�l �\�Z S�c3V�U4l \�]@Z�VtuZ�k�k�c3h�lxS1w � b�U*`�b�U*VYc3`�c@SR`�b�c@S�Z�]^`�U*VJh�Z�`Jc3WUo d VY`�b�Uai \�Z�](VJd \�`JU `Jb�U*dsV�_oA`�bTZ�`�k�VJd&W�c@i�U&S

!��>GI&[3�&'2T)+2@7�$?D�(/0+)+F90'0-(/GI7 G<7 $'=>( 0��<F92�0'$'(/G<7 :90-2@2$'=>21;361 2@&-0�(/7 B "�2@0-0'(/GI7 �<J9G6^���(/,/2@04: 36$'(/AV2@&4:�367;D"%$'2@_<2@790U��������]Z�b

{*|

Page 43: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ~ ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

`�b�U�Q�U&S�`jtjd i�U*].d�[ b \�tuZ&h X1dsl h�c^`�c3WU�Q�U*b�Z*W�c^d \�V4oCV�U*tuZ&c3h�SaZ�h U4tjk�c3VJc-X*Z&]Fc@S�S"\�U zpZ�hTiQ=U4_d h�ij`�b�U SJX1d k�U d�[�`�b�c@S `Jb�U&S"c@S���w

�NZ W c3h�l U S"`�Z&Q�]3c@S"b�U i `�b�U X*Z�kTZ X1c^`"_ d�[ X1dsh�h�U&X�`�c3dsh�c-S�` h�U*`�e,d V ��S `�d c3tmk�]3U*tmU1h `��\�ZsS"c^V�U*ls\�]-Z&VRtuZ&k�k�c^h�lS�o q `�b�U*huV�Z�c@S"UY`�b�U6X1VJ\�X1c-Z&] �\�U&S�`�c3dshnd&[DeCb�U*`Jb�U*V.S"\TX�buh�U*`�e,d V ��SZ X1`J\�Z�]^]3_ i�c � U*V6c3h `�b�U*c3V 24� ��1��$ G ��� � Z�V�X�b�c3`�U X1`�\�VJU [OV�dst `�b�Uni \�Z�].V�ds\�`�Uu`�b�U*d VJ_w � b�c-S��\�U S"`�c^d huc-SCZsi�i�VJU&S�S�U&i c^hni U*`�Z&c3] c^hu`�b�U S"\�Q�S"U��\�U*h `.X�b�Z�k�`JU*V*w

��� � ��� � � � � � �

PRh�U�d�[ `Jb�U ��V�S"`CS�c3lsh�c � X4Z�h `CX1dsh�h�U&X1`Jc3dsh�c-S�`9tmd i�U*]-S(d&[�Zjz �\�Z S�c3V�U4l \�]@Z�V1��]3c^h�l \�c@S"`Jc-XCtuZ�k��k�c3h�lY`�Z S �6eKZ S+jC\�tjU*]^b�Z�VJ`(Z&h�i $ X�D]3U*]^]-Z�hTi $ SDz�{4|(C(h�(k�Z&`�`JU*V�hmZ SJS"d X1c@Z�`�dsVFtjd i U*]�[OdsVD`�b�Ul U*h�U4V�Z�`Jc3dsh6d�[ �(h�ls]3c@S"b6k�ZsS"`��O`�U4h�S"U.WU*V�QTS1w � ��� �%�������j����� G *$-� � G � c@S(ZYS"c3tmk�]3U,X1dsh�h�U&X1`Jc3dsh��c-S"`�Z�V�X�b�c3`�U X1`�\�VJUD`�b�Z&`DX1d hTS"c-S�`�SAd�[ Z�S�U*` d&[ c3h�k�\�` \�h�c3`�S Z�hTi d \�`Jk�\�`(\�h�c3`�S [O\�]^]3_ X1d h�h�U&X1`JU&iQ�_Ytjd i�c(� Z�Q�]3UFe,U*c3lsb�`�S1w � b�U*V�UKZ�VJUCh�dYb�c-i�i U*h \�h�c3`�S d V([OU*U&i�QTZ X �YX1d h�h�U&X1`Jc3d hTS1w &xU*U g c3l �\�V�U }�w^{R[Od VNZ6S�X�b�U*tuZ&`�c@XRi�c@Z�lsV�Z�t d&[+jC\�tjU*]^b�Z�VJ`CZ&h�i $ X�D]3U*]^]-Z&h�i $ S.z�{4|(C(h�Ftmd i�U*]pw � dl U*h�U4V�Z�`JUD`�b�U,k�Z S�` `JU*h�S"U,d�[ ZCWU*VJQAo*`�b�UNz%U*hTX1d i�U&i=� S�`�U*t d&[�`�b�Z&` WU4V�QYc-S k�VJU&S"U4h�`JU&i�`�d.`�b�Uc3h�k�\�`F]-Z*_U*V�d�[ \�h�c^`�S�w � b�U&S"UNc3h�k�\�`CZ X�`�c3WsZ&`�c3dsh�SFZ&V�U�k�V�d kTZ�lZ&`�U&i [OdsV�eCZ&V�i `Jd6`�b�U.d \�`�k�\�`]-Z*_U*VDW�c@Zv`Jb�U�X�d h�h�U X1`�c^h�l e,U*c3lsb�`�S1o�eCb�c-X�b ta\�]3`Jc3k�]^_Y`�b�UYZsX1`�c^WsZ�`�c^d h�SDQ�_a`�b�UYS"`JV�U*h�ls`�bud�[U&Z X�bueFU*c^l b `*w � b�U VJU&S"\�]^`�c^h�luz%`Jb�V�U&S�b�d ]@i�U&i=�KZ X�`�c3WsZ&`�c3dsh�SCd hn`Jb�U ds\�`�k�\�`R\�h�c3`�SRZ&V�U `Jb�U*hi�U&X1d i�U i c^h�`JdaZ�h � h�l ]3c@S"bueFdsV�i w

q h;X1d h `�V�Z S"`Y`JdjtjdS�`�i \�Z�] V�ds\�`�U6tjd i U*]-S.i�c-SJX1\�SJS"U&i�S�d [�Z�V4o `�b�U k�Z�`J`�U*VJh#Z SJS"d X1c@Z�`�dsVc-SDZ�Q�]^U�`�d �3�J���� `Jd l U4h�U*V�Z&`�U�`Jb�U.k�Z S�`C`�U*h�S�U [OdsV�tuS [OdsVFl c^WU*h6WU*VJQ�S1w;� U&Z�VJh�c3h�l6c@S(c3tjk�]^U �tjU*h `�U&iYQ�_6k�VJU&S"U4h�`Jc3h�lYZYWU*V�QaS�`�U*t Z&`D`�b�U.c3h�k�\�`*o Z�hTijX1d tmk�Z�VJc3h�l�`Jb�U.k�Z S�`��O`�U*h�S�UR[Od VJt`�b�Z&`Fc-SDd \�`Jk�\�`CeCc^`�bj`Jb�UYi�U&S�c3VJU&i zO`�Z&V�l U4`1�(ds\�`�k�\�`*w q [A`�b�U*V�U�c@SFZ&h�_mi�c-SJX1V�U4k�Z�h�X�_oeFU*c^l b `X�b�Z&h�l U SCZ�V�UYtuZsi�U�c^h k�V�d k�dsV�`�c^d h�`�d6`�b�c-SCi�c@S�X1VJU*k�Z�hTX1_ `Jdji U&X1V�U Z S"UNc3`YzpS�U*UFjC\�tjU*]^b�Z�VJ`*o�Rc3h `�dshAo>� � c3]^]3c@Z�tuS�oA{*|(C�h�oA[Od VYZ&h:U*]@Z�Q�d V�Z�`Jc3d h#d�[,`Jb�c-SRe,U*]3] � � h�d&eChAo /���>�� � G ���*�x� �p$ G �Z�]3lsd VJc3`�b�tn��w

g VJd t ZL`JV�Z�c^h�c3h�l S"U*`md�[�& h ~ �(h�l ]^c-S�b WU*VJQ�S1oC`Jb�U�k�Z S�`u`�U*h�S�U�k�Z�`J`�U*VJh Z SJS"d X1c@Z�`�dsV]3U&Z&V�h�U&ij`JduX1d VJV�U&X�`�]3_mk�V�d i�\TX1U `Jb�U k�ZsS"`�`JU*h�S�U [OdsV�t [Od V |�{�� d&[D`�b�U `�V�Z�c3h�c3h�lmS"U*`4o=bTZ�h��i�]3c^h�l6Q�d `�b�V�U*ls\�]-Z&V.Z�h�iuU*r�X1U*k�`Jc3d hmWU*V�Q�S�w

�NSFX*Z&hjQ�UYS"U*U4h [OV�dst `Jb�U�S�`�VJ\�X1`�\�V�U�d&[ `�b�U�tmd i�U*] z g c^l \�VJU�} w3{&�(`�b�U*V�U�c@S9h�d U*r k�]3c@X1c3`

Page 44: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �R���[� ���� � � ��{

output layer

input layer

(460 units)

(460 units)

encoding weights

decoding weights

walk

walked

g c3l \�V�UY} w3{ f � b�UYk�ZsS"`.`�U*h�S�UYk�Z�`J`�U*VJhnZsS�S�d X1c-Z&`�d V0zMjC\�tjU*]^b�Z�VJ`�� $ X�D]3U*]^]-Z�hTi o�{*|(C�h���w

i�\�Z�]�VJd \�`JURc^h6`�b�U.k�Z�`J`�U*VJhjZsS�S�d X1c-Z&`�d V ��Z�]^]�WU*V�QTS1o U*r�X1U*k�`�c3dshaZ�h�iaV�U*ls\�]-Z&V*o Z�VJUCk�V�d X1U S�S"U iW�c@Z `�b�U S�Z&tjU�tuZ&k�k�c^h�l6k�V�d X�U&i�\�VJUo�c^tjk�]3U4tjU1h `�U i c3hu`�b�UYdsh�U S"U*`Cd&[DeFU*c^l b `�S�wjC\�tjU4]3b�Z&V�`DZ&h�i $ X�D]^U*]3]@Z�h�ijzJ{*|(C�h�� X1]-Z&c3tjU&iY`�b�Z&`F`Jb�U*c3VDtjd i U*]�i�U*tmd h�S�`�V�Z&`�U&i `Jb�Z�`

c3`(eKZ S9\�h�h�U&X1U S�S�Z&V�_6`Jdvk�dxS"`�\�]-Z�`JU�`�b�UCU*r�c@S"`JU*h�X1UCd&[Ac3h `�U4V�h�Z&]�V�\�]^U&S `Jd U*r k�]-Z&c3h6VJ\�]3U �OQ�ZsS"U&iQ=U4b�Z*W�c^d \�V4f

� UDb�Z*WUDS�b�d&eCh `Jb�Z�`�ZFV�U&ZsS"dsh�Z�Q�]^UCZsX*X1d \�h�`Ad&[�`�b�U Z X �\�c-S�c3`Jc3d hYd&[�k�ZsS"` `�U*hTS"UX*Z�huQ�U�k�VJd&W�c@i�U&i eCc^`�b�ds\�`CV�U&X�d \�V�S"U�`Jd6`�b�U�h�d `�c^d hud�[ Z ��VJ\�]3U �6Z SCZ�h _ `�b�c^h�ltjd VJU `Jb�Z�h Z �����4*��$ ���p$ G � d&[�`Jb�Uj]@Z�h�ls\�Z�lsUwLzMjC\�tjU4]3b�Z&V�`R� $ X�D]3U*]^]-Z&h�i o{*|�C(h�o�kAw+��ha^ �

g \�VJ`�b�U4V�tjdsV�Uo�`�b�U6[�Z X�`v`Jb�Z�`Y`Jb�U tmd i�U*](eKZ SYZ�Q�]^U `Jduc3tjk�]^U*taU*h�`.S�\�X�b#Z tuZ&k�k�c3h�leCc3`�b�d h�U \�h�c(��U&ijtjU&X�b�Z�h�c-S"t zpZ6k�Z&`�`�U4V�h#Z SJS"d X1c@Z�`Jd V1�Kk�\�V�k�dsV�`�U i�]3_�S"b�d�e,U&i `Jb�Z�`N`�b�U*VJUc-SFh�d # k�S�_�X�b�ds]3d lsc-X*Z&]3]^_6V�U&Z&] $�i�c@S"`�c^h�X1`Jc3d hmQ=U4`"e,U*U*hjVJU*l \�]-Z�VNZ�hTi U4r�X1U4k�`�c^d huc3`JU*tuS1f

� b�U.X�b�c3]@i h�U*U&ivh�d ` ��l \�V�UCd \�`(eCb�Z�`D`Jb�UFVJ\�]3U&S Z�VJUoh�d V�U*WU*hY`�b�Z&`D`�b�U*VJUCZ&V�UV�\�]^U&S1w � b�U X�b�c3]-iah�U*U&i h�d `Ni�U&X1c@i�UReCb�U*`�b�U4V.Z WU*V�Qjc@SFV�U*ls\�]-Z&VCd VCc^V�V�U4l \�]@Z�V*wzMjC\�tjU*]^b�Z�VJ`-� $ X�D]3U*]^]-Z&h�i o�{*|�C(h�o�kAw+��ha^ �

Page 45: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�(� ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

�.d�e,U*WU*V4o `Jb�U#tjd i�U*]�eKZ Sjh�ds`neCc3`Jb�d \�`nc3`�SuX1V�c^`�c-X4S1w ! c3h �U*VuZ�hTi ! V�c3hTX1U z�{4|(C(C�Z�`�`�Z X �U&ijc3`CQ�d `Jb [OdsVRQ�U*c^h�ljZ&hn\�hTX1d h W�c^h�X1c^h�l6tjd i�U*] d�[Db \�tuZ&hjk�ZsS"`.`�U*h�S�U lsU*h�U*V�Z�`�c^d hz�[Od VaU*r�Z�tjk�]3Uo(c^` k�VJd i�\�X1U i k�Z S�`j`�U*hTS"U [OdsV�tuS `Jb�Z�`mh�dLk�U*V�S�d h U*WU4V6eFd \�]-i oCS�\�X�b Z S/����5�` �5L� �,Z�h�i [OdsV�c3`�S k�dd V �����=����� �H$��4� �p$ G � k�U*V"[OdsV�tuZ&h�X1Uo�`Jb�Z�`�c@S1o�c3`�S ]^c3tjc^`�U&iaZ�Q�c^]3c^`"_`�duX1dsV�VJU&X1`�]^_jc3h ��U&X1`CWU*VJQ�SC`�b�Z&`�c3`.b�Z inh�d `�U*hTX1d \�h `�U4V�U&i�i�\�V�c^h�lj`JV�Z�c^h�c3h�l�w � b�U tjd i�U4]b�Z iLZ&h Z X*X1\�V�Z X�_�V�Z�`JUjd�[.dsh�]3_ ha^ � dsh ZnS�U*` d&[.h�d&WU*]DWU*V�QTS1o(Zuk�dd V6V�U S"\�]^` Q�d `JbLc3hl U*h�U4V�Z�]�tuZsX�b�c3h�U �O]3U Z�V�h�c3h�l.`�U*VJtuS1oxZ�h�i c^hjX�d tjk�Z&V�c@S"d ha`�d b�\�tuZ�hak�U*V"[OdsV�tuZ&h�X1Uw ! c3h �U4VZ�h�i ! VJc3h�X�U zJ{*|�C(C�� Z�`�`JV�c^Q�\�`�U i Q�ds`�bnd&[D`�b�U&S"UYk�VJd Q�]^U*tuSRz�Z�h�iud `Jb�U*V�S��F`Jd `Jb�U�[�Z X1`C`Jb�Z�``�b�Ujh�U*`�eFd V��#i�c-i#h�d `6c^tjk�]3U4t U�h�`.c3h `�U4V�h�Z&]9VJ\�]3U S1o(Z&h�i i�c-i#h�d `6tuZ �UaZ�h _Li c-S"`Jc3h�X�`�c3dshQ=U4`"e,U*U*h�V�U*ls\�]-Z&VYZ�h�inU4r�X1U4k�`�c^d hnc^`�U*t S�z%eCb�c@X�b�`�b�U*_�Z&]-S"d�ZsS�S"U4V�`�U inc-S #!k�S"_�X�b�d ]3dsl c@X*Z�]^]3_V�U&Z&] $ � ! c3h �U*V � ! V�c^h�X1Uo {*|�C(C���w

� b�U�jC\�tjU*]^b�Z�VJ`FZ&h�i $ X�D]^U*]3]@Z�h�i tmd i�U*] bTZ SCQ=U4U*hnlsU*h�U*V�Z�]3]^_jZsX � h�d&eC]3U i�l U&iuZsSRZ&hc3h�Zsi�U��\�Z�`JU k�S�_�X�b�d ]^d lsc-X*Z&] tjd i U*]Dz &U4c-i�U*h Q�U*V�l�o {4| |�����o Q�\�`�c^`ReKZ S�S�\�X*X1U&SJS [O\�]�Z�`Nk�V�ZsX��`�c-X4Z�]3]^_6i�U4tjd h�S�`�V�Z�`�c^h�l�ok�U*VJb�Z�k�S9[OdsVF`Jb�U ��V�S"`F`Jc3tjUxo b�d&e ��\TZ S"c^V�U*ls\�]-Z&VFtuZ&k�k�c^h�lSDX1ds\�]-iQ=UYc^tjk�]3U4t U*h `�U4i6eCc3`�b�d \�`.Z&hnU*r k�]3c@X1c3` i�\�Z�] V�ds\�`�U S�`�V�\TX1`�\�VJUw � b�UYk�dd V�lsU*h�U*V�Z�]^c �&Z&`�c3dshd�[ `�b�U�tjd i�U*]�o b�d&eFU4WU*V*o S"\�l l U S"`�U i `Jb�Z�`KZ V�U*k�V�U&S�U*h�`�Z�`Jc3d hTZ�] S�X�b�U*tjU.Z&h�i��4d V.Z h�U*`�e,d V �Z�V�X�b�c^`�U&X1`J\�V�U.d�[ tjd VJUYS"dsk�b�c-S�`�c@X*Z�`Jc3d hue,U*V�UYV�U ��\�c^V�U&i w

&x\�Q�S"U ��\�U4h�` X1dsh�h�U&X�`�c3dsh�c-S�`Atjd i�U*]@S d�[�`Jb�UFkTZ S"` `�U4h�S"U,b�Z*WUDi�d h�UCU*r�ZsX1`�]^_R`Jb�Z�`4oZ�QTZ�h��i�d h�c^h�lj`Jb�U6W�c^]3c(��U&i # � c@X �U*]B[OU&Z�`J\�V�U�$�VJU*k�VJU&S"U*h `�Z&`�c^d h z ! c^h �U*VW� ! VJc3h�X�Uo {4|(C�C �IjC\�tjU4] �b�Z�VJ`I� $ X�D]^U*]3]@Z�h�i o{*|(C�h���Z�hTiv\�S�c3h�l�]@Z�VJl U*V t \�]3`�c^]-Z*_ U4V=h�U*`�eFd V���S�o�eCb�c-X�bvk�V�d&W�c@i�UDtjd VJUX1d tjk�\�`�Z&`�c3dsh�Z�]Ak�d&eFU4V*w &\�X�bntjd i U*]-S�z Dd `�`JV�U*]^]I� ! ]^\�h �U*`J`*oA{*|s|�{ �5�NZ�\�lsb�U*V�`�_g� &U*c �i�U*h Q=U4V�l�o�{4| |(� � $ Z X � b�c3h�h�U4_�� � U*c^h�QTZ X�bAo�{*|s|�{ � ! ]^\�h �U*`J`+� $ Z&V�X�b�tuZ�h o�{4| | ~�Db�Z*WUZ X�b�c3U*WU int \�X�b�tjdsV�Uac3tjk�VJU&S�S�c3WU k=U4V"[Od VJtuZ�hTX1Uw q hL`�b�U ]@Z�`�U S"` tmd i�U*].zM��Z&\�l b�U*V�`�_ �&U*c-i U*h�Q�U*VJl�o {*|s|(����oAl U*h�U4V�Z�]^c �&Z&`�c^d hnV�Z�`JU&SRd�[,d&WU*VN| ~ � d h#h�d&WU*]AWU*VJQ�SCeFU*VJU V�U4k=dsV�`JU&i oZ�]3`Jb�d \�l bnc^`Cc-SCS�`�c3]^] `Jb�U X*Z S�Uv`Jb�Z�`.c3`Ck�V�d i�\�X�U&S U4V�V�dsV�SF`Jb�Z�`.h�d6b \�tuZ�hue,d \�]@i w

&xdneCb�c^]3UaX1dsh�h�U&X1`Jc3dsh�c-S�`vtmd i�U*]-S.d�[.`�b�U k�ZsS"` `�U*h�S�UaZ�VJUo(Z&` k�VJU&S"U*h `*o S�`�c3]^](h�ds` X�d h��W�c^h�X1c3h�l6Z SCk�S�_�X�b�d ]^d lsc-X*Z&] tjd i�U4]-S1o `�b�U4_ b�Z*WUYS�b�d&eCh�Z6k�V�dstjc-S�c3h�l0Z�Q�c^]3c^`"_6`Jd ]^U&Z�VJhuZ�hTic3tjk�]^U*taU*h` ��\�ZsS"c^V�U*ls\�]-Z&V�tuZ�k�k�c3h�lxS�z &U4c-i�U*h Q�U*V�l�oA{*|s|(���.eCc^`�b�ds\�`R\�`�c3]^c �*c^h�laZ�h�U*r k�]3c@X1c3`i�\�Z�]AVJd \�`JU6Z&V�X�b�c3`JU&X1`�\�V�Uw

Page 46: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � �\���@��� ��� � � � � � ��� � }����� � � � � � � � � ������� � � � �

$ Z�k�k�c^h�l �(h�ls]3c-S�bndsV�`�b�d l V�Z�k�b _ zpS�k�U*]3]^c3h�l �D`�djk�b�d h�ds]3d ls_ zpS�d \�h�i�S��Cc@S h�ds`�dsV�c3ds\�S"]^_�i�cB[ �� X1\�]^` � c^` c@S U4WU*hLSJZ�c@i:`�b�Z&` `Jb�Ujb�c^l bLc^h�X1c-i U*h�X1U6d&[.V�U&Zsi�c3h�l;i�c-S�d V�i�U*V�S Z�h�i�[O\�h�X1`Jc3d hTZ�]c3]3]^c3`JU*V�ZsX1_ c^h �(h�ls]3c@S"b���S"k�U&Z ��c^h�ljX�d \�h `�VJc3U&S,X*Z�huQ�U Z�`�`JV�c^Q�\�`�U i `Jd6`�b�UYc^V�V�U4l \�]@Z�V�c^`�_6d�[�`�b�U� h�l ]3c@S"b�S"k�U*]^]3c^h�luz $ Z&V�S"bTZ�]3]�� �RU*eKX1d taQ�Uo�{*|a^ }���w

�NS(i�c-SJX1\�SJS"U&i Z�Q�d&WUoZYi�\�Z&]�V�ds\�`�U,`�b�U*dsV�_mz Dd ]^`�b�U Z�V�`4o�{*|�^`C o={4|(Cs~ � Dds]3`Jb�U&Z�VJ`(U*`DZ&]pw^o{*| |s}�� b�ZsS Q�U*U*h6k�VJd k�dS�U&iE`Jd�U*r k�]3c@X*Z�`JUD`�b�U,`�U*r `���S"k�U*U&X�b t Z�k�k�c^h�l.d�[ �(h�l ]^c-S"b w � b�U.i�\TZ�]V�d \�`�U.`�b�U*dsV�_ U*r�k�]3c-X�c3`�]^_YX*Z&`�U*V�S�[OdsVDU*r�X�U*k�`�c^d h�S c3h �(h�l ]^c-S�bAob�_ k�d `�b�U&S"c �*c3h�lN`�b�U.U*r c-S"`JU*h�X1Ud�[ Z�hnc^h�`JU*V�hTZ�] ]^U*r c-X1dshj`�dmS"`Jd V�UY`Jb�U*c3VYzOtjU*tjdsV�c �1U&i��Ak�V�dsh�\�h�X1c-Z&`�c^d h�S�w

� b�U ��V�S�`)�Z&h�intjdxS"`C[�Z�tjds\�S ) X1d h�h�U&X1`�c^d h�c@S"`.c3tjk�]3U*taU*h `�Z�`JcBd hjd&[F`JU*r `��O`�d���S"k�U*U X�btuZ�k�k�c3h�lYeCZsS � � � `�Z�] � o Z }��%]@Z _U4V9h�U*`�eFd V��6`�V�Z�c3h�U&i `�d tuZ�k6c^h�i�c^W�c@i�\�Z�]�]^U*`�`JU*V�SFzOeCc3`Jb�c3h`�b�U�X1dsh�`JU*r�` d�[ Z�l VJd \�k d�[N]3U*`J`�U*V�S��Y`Jd#S"d \�h�i�Snz &U���h�d&e.S � cW�8jCdS�U*h Q=U4V�l�o.{*|�C(C��w �]3c3`J`�]^U � � h�d&eCh6[�Z X1`,c-S(`�b�Z&` � � � `�Z&] �6eCZsSCZ X1`J\�Z�]^]3_6k�VJd i�\�X1U i ZsSFZ6X�b�Z�]^]3U*h�l U.`�d `Jb�UYi�\TZ�]V�d \�`�Uj`Jb�U*d VJ_oAeCb�c-X�b#c-S�V�U*W c3U4eFU&inc^hLi�U4`�Z�c^]Dc3h j dxS"U*h Q�U*V�l�$ S i c-S�S�U*V�`�Z�`Jc3d h zMjCdS"U4h�Q�U*VJl�o{*|(C�C���wjCdS�U*h Q=U4V�lmS"`�Z&`�U&ij`Jb�Z�`4f

� b�U6l dxZ�]Dd�[,`Jb�U6h�U*`�eFdsV ��eCZ S.h�d `Y`�dm]3U&Z&V�h�`�b�U6k�V�dsh�\�hTX1c-Z&`�c3dsh�S�d�[,eCb�ds]3UeFdsV�i�S�o9Q�\�`6d h�]^_L`�b�Uuk�VJd h \�h�X1c@Z�`Jc3d hTS d�[ S�c3h�ls]3Uj]^U*`�`JU*V�S Z�k�k�U&Z&V�c3h�lLc3hL`Jb�UX1d h `�U4r�`(d&[Ae,d V�i�S1w � b \�S(`�b�UNi�U*WU*]^d k�tmU*h�`Ad&[ Z�]3U4r�c@X1d h6eKZ S(h�d `,h�U&X1U S�S�Z&V�_oZ�h�iY`�b�UDk�U*V�[Od V�t Z�h�X1U�d�[�`Jb�UDh�U*`�eFdsV ��VJU ��U&X1`�S b�d&e:ta\�X�b�d�[�`�b�UCS"k�U*]^]3c^h�l��O`�d �S"ds\�h�ink�VJd Q�]^U*t X*Z&hnQ�UaS"ds]3WU&i 8($3�-� G ��� e,d V�i �pS�k=U X1c � Xso=]^U*r�c@X*Z�] � h�d&eC]3U i�l UwzMjCdS�U*h�Q�U*VJl�oA{4|(C(C o=k w %s|��

� h�[Od VJ`�\�h�Z&`�U*]^_ [Od V,`�b�UNZ i�Wd X4Z�`�U S9d�[�X�d h�h�U X1`�c^d h�c@S"t�o&`�b�U.k�U*V"[OdsV�tuZ&h�X1U.d�[ � � � `�Z�] �d hn[O\�]^] e,d V�i�S z)& % � X�d V�VJU&X1` ��j dxS"U*h Q�U*V�l�o({*|�C(C�oAkAw %s|��.eFds\�]-iud h�]^_�S�U*U*t `�duX�d h ��VJtDd ]3`Jb�U&Z&V�` $!SAZ SJS"U*VJ`�c3dsh `Jb�Z�`�S � c3]^]3U&iRVJU&Z i c3h�l.k�U*V"[OdsV�tuZ&h�X1UDX1ds\�]-i�h�ds` Q�UKZ�`�`�Z�c^h�U&i 8($3�-� G ���S"d tmUR[Od VJt d�[D]^U*r c-X1dshAw

� tjd VJU,S"d k�b�c-S�`�c-X4Z�`�U ivtjd i�U4]d�[ eFdsV�ivhTZ�tjc^h�l z�Z�h�iYV�U&X�d l h�c3`�c^d h � eCZsS(i�U*WU4]3d k�U&i�Q _&U*c-i U*h�Q�U*VJl.Z�h�i $ X�D]3U*]^]-Z�hTi z�{4|(C |��w � b�U4_vk�V�d k�dxS"U&i6ZsS `Jb�U*c3V tjd i�U4]ZF[O\�]3]^_ ��X1d h�h�U&X1`JU&iV�U&X1\�V�V�U4h�`jh�U*`�eFd V�� eCc^`�b &~ ~ c3h�k�\�`j\�h�c^`�S�oR[OU*U&i�Q�ZsX � X1dsh�h�U&X�`�c3dsh�SjQ�U*`�eFU*U*h `Jb�U � ~ ~

Page 47: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�]& ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

b�c-i�i U*h \�h�c3`�SFZ�hTi `�b�UNc3h�k�\�`9]@Z*_U*V*oZ&h�i &�hs~vd \�`�k�\�`C\�h�c3`�S z�S"U*U g c3ls\�V�UN}�w ����w q h�S�`�U&Zsi d�[S"c3h�l ]3UY]^U*`�`JU*V�S�o�`�b�c@S h�U4`"e,d V��jeCZsS `JV�Z�c^h�U&iu`�dak�V�dsh�d \�hTX1U6eCb�d ]^UjzOtjd h�dxS"_ ]3]@Z�Q�c@X��(e,d V�i�S1w� b�c-S6eFdsV � eCZsS S�k=U X1c � X4Z�]3]^_ i�c^V�U&X1`JU&i:`Jd�eKZ�V�i�S tjd i�U4]3]3c^h�lnb \�tuZ&h k=U4V"[Od VJtuZ�hTX1UoDZ�hTi&U*c-i U*h�Q�U*VJl#Z�h�i $ X�D]3U4]3]-Z&h�iLX1dstjk�Z&V�U&i:`Jb�UnQ�U*bTZ W c3ds\�V6d�[ `�b�U*c^V6h�U*`�eFdsV �L`Jd:b \�tuZ&hV�U&Zsi�c3h�lai�Z�`�Z w

hidden layer(200 units)

orthographical layer(400 units)

phonological layer(460 units)

feedback connections

have

/hav/

g c3ls\�V�UY} w � f � b�U &U*c@i�U*h Q�U*V�l0Z�h�i $ X�D]^U*]3]@Z�h�iuz�{4|(C |�Fh�U*`�eFd V��E[OdsVCtuZ�k�k�c3h�l tjd h�dS"_ ] �]-Z�Q�c-X �(h�ls]3c-S�bne,d V�i�S `JdaS"d \�h�i�S1w

$ Z&h�_atjU&Z&h�c3h�l�[O\�]�Q�U*bTZ W c3ds\�V�Z&]AX1dsV�VJU*]-Z&`�U&SDeFU*VJU [Ods\�h�i w��Rd&e,U*WU*V*os`�b�UR[�ZsX1U*`,d�[ `�b�c-Stjd i�U*]�`�bTZ�`Cc-SFk�U*VJ`�c^h�U*h `F`�d6`Jb�c-S,i�c-SJX1\�SJS"c3dshuc-SFb�d&e eFU*]^]=c^`FeKZ SCZ�Q�]3UY`�d6c^tjk�]3U4t U*h`�`�b�Uz �\�Z S�c3V�U4l \�]@Z�V1�Dt Z�k�k�c^h�l6d�[ S"k�U*]^]3c^h�l6`�dmS"ds\�h�i w

&xU*c-i�U4h�Q�U*VJl Z�h�i $ X�D]^U*]3]@Z�h�i zJ{*|(Cs|��mV�U*k�d VJ`�U&i `�bTZ�`u`�b�U�tmd i�U*]�]^U&Z�VJh�U&i `�d k�VJd��h�d \�hTX1U.X1d VJV�U&X�`�]3_ Z&]3] Q�\�`�^(^.d�[ `Jb�UW�(Cs|a^�`JV�Z&c3h�c^h�l�eFdsV�i�S ) ZYX1dsV�VJU&X1`�h�U&S�SAV�Z&`�U.d�[ |a^xw } �mw� b�c-SDeCZ SCZ&huc3tjk�VJU&S�S�c3WU,V�U&S�\�]3`,`�b�Z&`F[�Z�VFU4r�X1U4U&i�U&i � � � `�Z&] � $ S9k�U*V�[Od VJtuZ�h�X�U zOd h�U�ta\�S�`�U*U*k�c3h#tjc^h�i o b�d&e,U*WU*V*oA`Jb�Z�` `�b�U &U*c@i�U*h Q=U4V�l�Z�h�i $ X�D]3U*]^]-Z&h�iLz�{4|(C |�Yh�U*`�eFdsV ��eCZ SZ�k�k�]^c3U&i6d h�]3_6`�d tjd h�dS"_ ]3]@Z�Q�c@XFeFdsV�i�S���wFP.hj`�b�URQ�ZsS"c@S9d�[ `Jb�c-S(k�U*V�[Od V�t Z�h�X1Uxo &xU*c-i�U4h�Q�U*VJlZ�h�i $ X�D]3U*]^]-Z&h�iEk�V�d X1]@Z�c3tmU&i `�bTZ�`*f

q h#X1d h `�V�Z S"` `�du`�b�Uai�\�Z�]DVJd \�`JU tjd i U*]po `Jb�U*VJUaZ�V�Uah�d�V�\�]^U&S�S"k�U&X�c [O_ c3h�lj`Jb�UV�U*ls\�]-Z&V,S"k�U*]3]^c3h�l �pS�d \�hTijX1d VJV�U&S�k�d h�i�U4h�X1U&SDd�[ `�b�UR]@Z�h�ls\�Z�lsUo�Z&h�i `�b�U*V�U.c-S(h�d]3U*r c-X�d hnc^hneCb�c@X�b�`Jb�U k�V�d h \�h�X�c-Z�`Jc3dsh�S�d�[KZ�]^]Wl � h�d&eCh�m eFd V�i�SYZ�VJU6]3c-S�`�U&i#w3w^w3wP.h�UCd�[ `�b�UCtuZ&c3h0X1d h `�VJc3Q�\�`Jc3dsh�S d�[ `�b�UCtmd i�U*]�c@S `�b�Z&`Dc3`Di�U4tjd h�S�`�V�Z�`�U S `�b�Z&`

Page 48: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � �\���@��� ��� � � � � � ��� �&%k�V�dsh�\�h�X1c-Z&`�c^d hLd&[.U*r�X�U*k�`�c^d h#eFdsV�i�S6Z&h�iLh�d h eFdsV�i�S X*Z�h Q�UuZ X4X1d tjk�]3c-S�b�U&iQ�_aZYS�c3h�ls]3U.tjU&X�b�Z�h�c@S"t�w�z &U*c@i�U*h Q�U*V�lF� $ X�D]3U*]^]-Z&h�i o�{4|(C | o�k�kAw %`&�C�� %]&x|���w

� b�c-S6]3U*WU*]Dd&[Yk�U*V"[OdsV�tuZ&h�X1U�X1d \�]-i oDb�d&eFU*WU4V*oDb�Z*WUjQ�U*U*h ZsX�b�c3U*WU&i#Q�_L`Jb�U*c^V6]-Z�VJl Uh�U*`�eFdsV �aS"c^tjk�]^_�# tjU*tad VJc �*cBh�l�$ `�b�U�tuZ�k�k�c3h�l�[OdsVCU&Z X�b c^h�i�c^W�c@i�\�Z�]�e,d V�ijc^hj`�b�UN`�V�Z&c3h�c^h�lS"U*` z%`Jb�U h�U4`"e,d V��jb�Z i � %(� o h(hs~jeFU*c^l b `�S1o�eCb�c@X�buc-S.Z�]^tjdS�` {4~ ~ `Jc3tjU S9l VJU&Z�`JU*V.`�b�Z&h�`�b�Uh�\�taQ�U*V(d&[AeFdsV�i�SDc3ha`�b�UN`�V�Z&c3h�c^h�l S"U*` � ��w q h ds`�b�U4VFeFdsV�i�S�o�\�S�c3h�lY`Jb�U�`�U4V�tjc^h�d ]^d l _Yd&[ `�b�Ui�\�Z�]�V�d \�`�U `Jb�U*dsV�_o `Jb�U h�U*`�eFd V��utuZ*_uS"c^tjk�]3_mQ=U6c^tjk�]^U*t U4h`�c3h�l6Z ]@Z�V�lsUuzpi�c@S"`JV�c3Q�\�`�U&i��]3U*r c-X1dshAw � d i�U4`�U*VJtjc3h�UDcB[Ac3`�V�U&Z&]3]3_Yb�Zsi ]3U Z�V�h�U&i `�b�UCc^h�`JU*h�i�U i'��\�ZsS"c^V�U*ls\�]-Z&V9`JU*r `���S"k�U*U&X�btuZ�k�k�c3h�l�o�c^`DeFd \�]-i Q�U�W c3`�Z�]�`�d ��h�d&e b�d&e e,U*]3]�c3`DlsU*h�U*V�Z�]3c �*U&S(`�d eFdsV�i�SFh�ds`Fk�VJU*W c3d \TS"]3_S"U*U*h w � h�[OdsV�`J\�h�Z�`JU*]3_xo &xU*c-i�U4h�Q�U*VJl Z&h�i $ X�D]3U4]3]-Z&h�ijz�{4|(Cs|��D\�S�U&i `�b�U*c3VDeCb�ds]3UNX1d VJk�\�SFd�[tjd h�dxS"_ ]3]@Z�Q�c@XveFdsV�i�SYZsSv`�b�U `JV�Z�c^h�c3h�luS"U*`4o S"dnh�d lsU*h�U*V�Z�]^c �&Z&`�c3dsh#S"`�Z�`�c@S"`Jc-X*S�eFU4V�UaZ*WsZ�c3] �Z�Q�]^Uw � b�UYk�U*V"[OdsV�tuZ&h�X1U�d&[(`Jb�UYtjd i�U*] d huh�d h eFdsV�i�SCeCZsSCZ�]@S"dah�d `.i�c@S�X1\TS�S"U i c^h�i�U*`�Z&c3]�w�Rd&eFU*WU*V4oc3huZ [Od ]^]3d&eC\�k�S"`J\�i�_o y U&S"h�U4V*o � eCc^]3]^U*_o $ X�,Z�h�hAo�Z�h�i &U*U*VJl dsQ�c3h#z�{4| |s~��KZ�k��k�]3c^U&i `Jb�U�&U*c@i�U*h Q=U4V�lmZ�h�i $ X�D]3U4]3]-Z&h�i�z�{4|(C |��tjd i U*]A`�d�S"`�Z�h�i�Z�V�i#S"U4`�SRd&[Ch�dsh�e,d V�i�S1oZ�h�i [Od \�h�i WU*VJ_ tmd i�U&S"`,k�U*V"[OdsV�tuZ&h�X1Uf V�Z�h�l c3h�lE[OVJd t % {�� `Jd h % � X1dsV�VJU&X1`*o�X1d tmk�Z�VJU&ieCc3`�b�b \�tuZ&h#S"\�Q���U X1`�S"$ k�U*V"[OdsV�tuZ&h�X1U d&[.Z&V�d \�h�iL| ~ � d h#`�b�UmS�Z&tjUaS"U4`�S1w � c �U ! c3h �U4VZ�h�i ! VJc3h�X�U6z�{4|(C(C��o y U S"h�U*V,U*`.Z�]�wAz�{4| | ~�.Z�]@S"dmZ�`J`�V�c^Q�\�`JU&ij`�b�U&S�U i�c-SJZ�k�k�d c^h�`Jc3h�laV�U S"\�]^`�S`�du`�b�Uatjd i�U4] $ SC]-ZsX ��d�[ Zni�\�Z&]DV�d \�`�UatjU&X�b�Z�h�c@S"t �=`Jb�U*_#S�k=U X1\�]-Z&`�U&in`Jb�Z�` `�b�U�&xU*c-i�U4h��Q=U4V�l6Z&h�i $ X�D]^U*]3]@Z�h�i tmd i�U*] ���� S�c3tjk�]^_YtjU*tjdsV�c �4U&i�eFd V�i�S1o�c^tjk�]^U*t U�h `�c3h�l�S�d tjU.S�d V�`d�[N]3U*r c-X1dshAw � b�c-SYc3h `�U*VJk�V�U*`�Z�`Jc3d h eCZ SY`�b�ds\�l b `6`�d�U4r�k�]@Z�c^hLc3`�Svtjd i�U S"` lsU*h�U*V�Z�]^c �&Z&`�c3dshk�V�dsk=U4V�`�c^U&S1w

q huZ VJU*k�]^_6`�d y U&S�h�U*VFU4`CZ�]�w zJ{*| |s~���o &U4c-i�U*h Q�U*V�l Z&h�i $ X�D]3U*]^]-Z&h�i zJ{*|s| ~��KS"ds\�l b `.`�dQ�]-Z&tjUR`Jb�U�k�dd V.l U4h�U*V�Z&]3c �&Z�`Jc3d had�[�`�b�U�tjd i�U*]�h�ds`Cd hu`�b�U�]-ZsX �6d&[DZ i�\�Z�]AVJd \�`JUo�Q�\�`Fdsh`�b�U S"c �*U�d&[D`�b�UN`�V�Z&c3h�c^h�lmS"U*`4f(c3`FeKZ SC]3U&SJSF`�b�Z&h�}s~ ~ ~6eFdsV�i�S�o=eCb�c3]3UN`�b�UYWd X*Z&Q�\�]-Z&V�_jd&[,Zh�d VJtuZ�]�V�U Z i�U*VCe,d \�]@i Q�U Z�V�ds\�h�i�} ~�o!~ ~s~�w &U*c-i U*h�Q�U*VJl6Z&h�i $ X�D]3U*]^]-Z&h�i zJ{*|s| ~��KZ�VJl \�U i`�b�Z&`C`�b�U�h�U*`�eFd V�� $!SDZ�Q�c^]3c3`�_6`Jd6k�V�dsh�d \�hTX1UYh�d h eFdsV�i�SFeKZ SCZ�Q�ds\�`.Z SFlsdd inZ SFdsh�UYeFds\�]-iU*r�k�U&X�` [OVJd t Zub�\�t Z�h#eCc3`�b ZnS�c3tjc^]-Z&V�]3_u]^c3tjc^`�U&ijWd X*Z&Q�\�]-Z&V�_w q [Ktjd VJU `JV�Z�c^h�c3h�lni�Z�`�ZeFU*VJUjZ*WsZ�c^]-Z�Q�]3Uo `�b�Ujh�U*`�eFd V�� $!Svk�U*V�[Od V�t Z�h�X1UaeFds\�]-i#c3tjk�VJd&WU6k�V�dsk=dsV�`Jc3d hTZ�`�U4]3_w � b�U*_eFU*VJUo b�d&eFU4WU*V*o \�h�Z�Q�]^UC`�d0i�U*tjdsh�S"`JV�Z�`JUC`�b�c@S k�d c^h�`DQ�U&X*Z&\�S"Uo ZsS9h�ds`�U&iaZ�Q�d&WUo`�b�U4_ b�ZsiZ�]3VJU&Z i _jU*r b�Z�\�S�`�U&ij`Jb�U S"\�k�k�]3_jd&[Dtjd h�dS"_ ]3]@Z�Q�c@X �(h�ls]3c@S"bne,d V�i�S1w

Page 49: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�(h ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

� b�c3]3U � � � `�Z�] �#z j dxS"U*h Q�U*V�l�o({*|�C(C��NZ&k�k�U&Z�VJU&in`�djc^tjk�]^U*t U�h ` ��\�S�`R`Jb�U � G � �p�3���s$-�� �V�d \�`�Uo &U4c-i�U*h Q�U*V�laZ&h�i $ X�D]3U*]^]-Z�hTi $ S.z�{*|�C |�Ctjd i�U*] Z&k�k�U&Z�VJU&i `Jd ��\TS"`.c3tjk�]^U*taU*h�`�`�b�U�3���s$-�� � V�ds\�`�Uw � b�UF[�Z X�`(`�b�Z&`(Q�d `Jb tjd i U*]-S Z X�b�c3U4WU&i�d h�]^_ tjd i�U S"` V�U&Zsi�c3h�lNk=U4V"[Od VJtuZ�hTX1UeFd \�]-i \�h�i�d \�Q�`�U&i ]3_ub�Z*WU Q�d ]@S"`JU*V�U&iu`�b�U0i�\�Z&] VJd \�`Jc-S"`�S�$AX�d h W�c@X1`�c^d hu`�b�Z&`R`�e,djS�U*k�Z�V�Z�`JUV�d \�`�U&SCZ&V�U ��� � � $-���J� `JdjZsX�b�c3U*WUNZ S ��c^]3]^U&i ]3U4WU*]�d�[�V�U&Zsi�c3h�l�w

� b�UvtmdS"`,V�U&X�U*h�`KX1d h�h�U&X1`Jc3d h�c-S"`,tjd i�U*] d�[�V�U&Zsi�c3h�laZ�]3ds\�i o�k�VJU&S"U4h�`JU&i Q _ ! ]-Z&\�`.Z�hTi$ X�D]3U*]^]-Z&h�i:zJ{*| |s}���o b�ZsSvk�VJd�WU i [�Z�VYtjd VJU6S�\�X*X1U&SJS [O\�]�w � b�Uatjd i�U*] eCZsSvc^tjk�]3U4t U�h�`JU&ic3h Z S"tuZ&]3]^U*V h�U*`�eFd V�� `�b�Z&h &U4c-i�U*h Q�U*V�l Z�h�i $ X�D]3U4]3]-Z&h�i $!S1f:dsh�U�`�bTZ�`�X1d hTS"c-S�`�U&i d�[{*~(CLc^h�k�\�`�zOl V�Z�k�b�U4tjU � \�h�c3`�S1oY{*~s~Lb�c-i�i U*h \�h�c^`�S1o.Z&h�i %�^#d \�`Jk�\�`�zOk�b�d h�U*tjU � \�h�c^`�SzpS"U4U g c3ls\�V�U;}�w }��w � b�U�l VJU&Z�`J]3_ V�U&i�\TX1U&i S"c �*Und&[ `�b�U�c^h�k�\�`uZ&h�i d \�`Jk�\�`j]@Z _U4V�S6eCZ StuZ i�Umk=dxS�S�c3Q�]^U Q _L`Jb�Uu\�`�c^]3c � Z�`�c^d hLd&[ ZntjdsV�UuX1dstjk�ZsX1` VJU*k�V�U S"U*h `�Z&`�c3dsh�Z�].SJX�b�U*tjU6[Od VU*h�X1d i�c^h�l6c3h�k�\�`.Z�hTi ds\�`�k�\�`RkTZ�`�`JU*V�hTS1w���SFe,U*]3]�o�`Jb�UYh�U*`�eFdsV �mX1d h `�Z&c3h�SFtmd V�U.[OU*U&i�Q�ZsX �X1d h�h�U&X1`�c^d h�S�z�Z SCc3]^]3\�S�`�V�Z&`�U&iac3h g c3ls\�V�U } w }���w

� S"c3h�l &xU*c-i�U4h�Q�U*VJl Z�h�i $ X�D]^U*]3]@Z�h�i $!S zJ{*|�C |��u`JV�Z&c3h�c^h�l S"U4`*o�`�b�U�tjd i�U*]YZsX�b�c3U*WU&i| |�w ^ � ZsX*X1\�V�Z X1_6c^h6k�V�dsh�d \�hTX1c3h�l `�b�U.eFdsV�i�S(c^h `Jb�UR`JV�Z&c3h�c^h�lYS"U4`*o Z�h�ial V�U Z�`�]^_ c^tjk�V�d&WU&iZ X*X1\�V�Z X�_6c3hah�d h eFdsV�i VJU&Z i�c^h�l�fA[OV�dst ^ ~v`�d0| ~ � dshuS"`�Z�h�i�Z&V�ijS�U*`�SDd�[ h�d h eFdsV�i�S�o�eCb�c-X�bc-SCZ�Q�ds\�`RU ��\�Z&]A`�dab�\�tuZ�hjk�U*V�[Od VJtuZ�h�X�U6z ! ]-Z&\�` � $ X�D]^U*]3]@Z�h�i o�{4| | }��w

feedback connections

hidden layer(100 units)

bike

/bIk/

phonological layer(57 units)

orthographical layer(108 units)

g c3ls\�V�U }�w!}�f � S�X�b�U*tuZ&`�c@XRi�c@Z�lsV�Z�t d&[D`�b�U ! ]-Z�\�`�Z&h�i $ X�D]3U4]3]-Z&h�inzJ{*| |s}��Ch�U*`�eFd V��j[Od VtuZ�k�k�c3h�l tjd h�dxS"_ ]3]@Z�Q�c@X �(h�l ]^c-S"bue,d V�i�S `JdjS�d \�h�i�S1w

� b�U �\�U&S"`Jc3dsh h�Z&`�\�V�Z�]3]^_ Z�V�c@S"U&S Z S `�d.eCb�_Y`�b�U ! ]-Z&\�`(Z&h�i $ X�D]^U*]3]@Z�h�i zJ{*|s| }�� tjd i U*]poeCb�c-X�b�c-SRQTZ S"U i dsh:`Jb�UjSJZ�tjUmzpX1dsh�h�U&X�`�c3dsh�c-S�`1�Ck�V�c3hTX1c3k�]^U&S.Z Sv`Jb�U�&U*c@i�U*h Q�U*V�luZ&h�i $ X��

Page 50: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � �\���@��� ��� � � � � � ��� �a^

D]3U*]^]-Z�hTi zJ{*|�C |��0tjd i�U*]�o(b�Z SaS"\�X4X1U*U&i�U i eCb�U*V�Uu`�b�U k�V�U*W c3ds\�SEtmd i�U*]FbTZ S [�Z�c3]^U&i w �Rdi�U*`�Z&c3]^U&ijX1dstjk�Z�VJc-S�d hjQ�U*`�eFU4U*h `Jb�UY`�eFd h�U*`�eFd V���SDb�Z SC_U*`DQ�U*U*h�X*Z&V�V�c^U&i ds\�`*o�Q�\�`C`�b�U*VJUZ�V�UY`Jb�V�U*UYdsQ�W c3ds\�SCZ S�k=U X1`�SCc3hueCb�c@X�bu`�b�U*_ji c � U*V*w

g c3V�S�`�]^_oA`�b�U ! ]@Z�\�`0Z�h�i $ X�D]^U*]3]@Z�h�i z�{4| | }�Yh�U*`�eFdsV �#c-S�ta\�X�b �456� �^�3��� o9eCc^`�b ��\TS"`d�WU4V(} %�o ~s~ ~YeFU*c^l b `�S1osX1dstjk�Z�VJU&iveCc^`�b6d&WU*V+� % ~ o ~ ~s~vc^h `�b�U &U*c-i U*h�Q�U*VJlYZ�hTi $ X�D]3U*]^]-Z&h�iz�{*|�C |�jtjd i�U4]pw � b�U#h�\�taQ�U*Vad�[atjd i�c(� Z�Q�]3U�eFU4c3l b `�Sac-Sj`�b�ds\�l b `n`Jd Q=U d h�U#d�[0`�b�U[�Z X1`Jd V�S�`Jb�Z�`Yi U*`�U*VJtjc3h�U&SF`�b�U6lsU*h�U*V�Z�]^c �&Z&`�c3dsh#Z�Q�c^]3c^`"_md�[.Zah�U*`�eFdsV �Lz �Rc3h `�dshAo({4|(C(h��o S"d`�b�c@SRS�c �*U0i�c � U*VJU*h�X1U X1ds\�]-iuk=dxS�S�c3Q�]^_nU*r k�]-Z&c3h ! ]-Z&\�`YZ�hTi $ X�D]3U*]^]-Z&h�i $ S�zJ{*|s| }��NS�\�k�U*V�c^d Vk=U4V"[Od VJtuZ�hTX1U�d h�h�d h eFdsV�i�S�w

� S"U&X1dsh�iui�c � U*VJU*h�X1Uxo�Z&h�ij`�b�UYdsh�U�`�bTZ�` ! ]-Z&\�`.Z�h�i $ X�D]^U*]3]@Z�h�iuz�{4| |s}��KZ�k�k�Z&V�U*h `�]^_X1d h�S�c-i�U4V(`�b�U.tjdxS"`(c^tjk�d V�`�Z�h `*o&c-S(`�b�UCc3h�X1VJU&Z S�U&i \�S�URd&[ ���J4���������� � c^h `Jb�U*c^V(tjd i�U*] ��`Jb�Z�`c-S1o[OU*U&i�QTZ X �jX1dsh�h�U&X�`�c3dsh�SFeFU4V�UYS�k=U X1c ��U i eCc3`Jb�c3h�Z�hTi Q�U*`�e,U*U*hj`Jb�UYb�c-i�i U*h�Z�h�ijd \�`�k�\�`]-Z*_U*V�S�w ! ]-Z&\�`.Z�hTi $ X�D]^U*]3]@Z�h�iuz�{4| | }�.S"\�l l U S"`.`�b�Z&`C`�b�c@SCZ�V�X�b�c^`�U&X1`J\�V�Z&]=[OU&Z&`�\�VJU X*Z�\�S�U&S`�b�Ujh�U*`�eFd V���`�d;i�U*WU*]^d k #BZ�`J`�V�Z X1`Jd V�S"$ eCb�c@X�b U*r�k�]3d c^`Y`�b�UjhTZ�`�\�V�Z�]KX1d tmk=dsh�U*h `�c@Z�]3c^`�_nd�[`�b�UY`�ZsS �j`Jd k�V�d tmd `�UNl U*h�U4V�Z�]^c �&Z&`�c^d h�Z�Q�c^]3c^`"_xw

P.`Jb�U*VaX1dstjtjU*h `�Z&`�d V�S�b�Z*WUuX*Z S�`ai�d \�Q�` dsh `Jb�c-S6ZsS�S"U4V�`�c^d hAo,Z�VJl \�c^h�l#c3h�S�`�U&Zsi `Jb�Z�``�b�U0X*Z�VJU1[O\�]3]^_uX�b�dS�U*h�c3h�k�\�`�Z&h�ind \�`�k�\�`NV�U*k�VJU&S"U4h�`�Z�`�c^d h�SC\�S�U&inc3h�`�b�c@S tjd i U*] ) eCb�c-X�bQ�V�U&Z � c3h�k�\�`�SuZ�hTi d \�`Jk�\�`�Sni�d&eCh c3h `�d `�b�U4c3VjlsV�Z�k�b�U*tjc@X�Z�h�i k�b�dsh�d ]^d l c@X*Z�]0X1d tmk=d �h�U*h `�S9VJU&S"k�U&X�`�c3WU4]3_uz �.h�i�V�U4e.S1o {4| |`&���)jb�Z*WUYZ � d V�i U&i `Jb�U # Q�V�U&Z � �O`�b�VJd \�lsb $3w��.h�i�V�U4e.S�$z�{*|s|]& �DZ�hTZ�]3_�S"c@S(c-S(S�\�k�k�d VJ`�U&i Q _v[Ods]3]^d�eC\�k6eFd V��6Q�_ ! ]-Z�\�`FZ&h�i $ X�D]3U*]^]-Z&h�iv`Jb�Z�`,S"b�d�e.S`�b�Z&` ds`�b�U4V�eCc-S�U�c-i�U4h�`Jc-X*Z&]Ch�U*`�eFdsV ��S eCc3`Jb � G [OU*U i�Q�Z X � X1d h�h�U&X1`Jc3d hTSjZ X�b�c3U4WU �JU&S�S�U*h��`�c-Z&]3]^_LU��\�c3WsZ�]^U*h ` �nk�U*V"[OdsV�tuZ&h�X1U�z � w ! ]@Z�\�`4oCk=U4V�S"dsh�Z�]NX1dstjt \�h�c-X*Z&`�c^d hAo g U4Q�V�\�Z&V�_ {]^{*| |`&�� X1c3`JU&i eCc^`�bnk�U*VJtjc-SJS"c^d h ��w

� bTZ�`�U4WU*VF`Jb�UYi�U&X�c-S"c^WUCc3h�h�d�WsZ&`�c3dshjeCZsS1o�`Jb�U ! ]-Z&\�`.Z�h�i $ X�D]^U*]3]@Z�h�ijzJ{*|s| }��,tjd i�U4]Z�k�k�U&Z&V�S9`Jd�b�Z*WU ��h�Z&]3]^_v[O\�VJh�c-S�b�U&i `�b�UCk�V�dd&[ `�b�Z&`FX�d h�h�U X1`�c^d h�c@S"`(tjd i U*]-SAb�Z*WUC`�b�U.Z&Q�c3] �c3`�_u`�duS�\�X*X1U&SJS [O\�]^]3_uc3tmk�]3U*taU�h�`KX1d tjk�]3U*r �\�ZsS"c3VJU*l \�]-Z�VNtuZ�k�k�c3h�lxS eCc^`�b�ds\�`YV�U��\�c3VJc3h�lmZi�\�Z�]AVJd \�`JU6Z&V�X�b�c3`JU&X1`�\�V�Uo Z�]^`�b�ds\�l b o Z&lZ�c^hAo�`�b�UYtjd i�U4] c-SF]^c3tjc^`�U&i `Jd��\�c^`�UYZ6V�U&S�`�VJc-X1`JU&i`�Z S � z%c�w Uw^o V�U&Zsi�c3h�l tmd h�dxS"_ ]3]-Z&Q�c-X e,d V�i�S�� � w��C`YZ VJU&X1U*h `YS"_ tjk�dS�c3\�t;o Dds]3`�b�U&Z�VJ` X�d h��

� � , 3MF9$ 367 D � ) R,/2@,/,*367;D Q9F9(/,/$ 360'0-F9A 1>$'(/GI790�(/7�$'G $-=92�A G9D�2@,[$-=;36$VGI79,/. =9GI,*D ^ G<& A G<79GI0-.�, ,*3MQ9( )aRGI&+D�0�� ^ G<&2��;36AV19,/2I: 19=9G<792@AV2�GI&SD%2@&�GI7 $'=92VGIF9$-19F9$'0�a[360�2@7;)#G%D%24D Q]. = 3T_](/798 0'2@1;3M&S3M$'2�19=9G<792@A 2F>79(/$'0R^ G<& $-=92GI7>0'2@$T:9_IG6aR2@, 3M7;D�)+G9D93�0'24)#$'(/GI790`G6^ 243I)-=�a G<&SDPb

Page 51: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�(C ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

X1U&i�U&in`Jb�Z�`Y`Jb�U ! ]@Z�\�` Z�hTi $ X�D]^U*]3]@Z�h�intmd i�U*] k�V�dsQ�Z�Q�]^_#i�c-S�k�V�d&WU&inb�c-SYS"`JV�d h�l�X1]@Z�c3t`�b�Z&`�Zai�\�Z&](V�ds\�`�U0Z�V�X�b�c^`�U&X1`J\�V�UNc-S ��� � ��$-���J� `Jd VJU&Z i � h�l ]3c@S"b�`�U*r `.Z�]^d \�i o Z�hTi�X�b�dxS"U `�dZ�`�`�Z X �j`�b�Uvtmd i�U*]Ac3hTS"`�U Z ijd h;i�c � U*VJU*h�`ClsV�ds\�h�i�S�o=h�Z&tjU*]^_ `Jb�Z�`.c3`CeKZ SCh�d `.k�S"_�X�b�d ]^d l c �X*Z�]^]3_aV�U&Z&]3c-S�`�c@X z Dds]3`�b�U&Z�VJ`*oA{*|s|]&sQ ��w

����� � ����� � ����� ��

� b�UR[�Z X�`9`Jb�Z�`,tuZ�h _ U Z�V�]^_aX1d h�h�U&X1`Jc3d h�c-S"`,tjd i�U*]@S eFU4V�U.\�h�Z�Q�]3U�`Jd6S"\TX*X1U&SJS [O\�]^]3_6X4Z�k�`J\�V�U`�b�Ujc^h�`JV�c@X*Z X1c^U&SRd&[NX1d tjk�]3U*r ��\�ZsS"c^V�U*ls\�]-Z&V tuZ&k�k�c3h�lS1o�S"\�X�b Z S `�b�Ujl U*h�U*V�Z&`�c3dshLd�[.kTZ S"``�U*h�S�U&S1o&d V�V�U&Zsi�c3h�l.`�U4r�` Z&]3d \Ti o ]3U ivk�VJd tjc^h�U*h `Ai�\�Z&]�VJd \�`Jc-S�`�S `Jd�X1dsh�X1]^\�i�UD`�b�Z&`(`�b�UCX*Z&\�S"Ud�[D`Jb�c-SCc3h�Z&Q�c3]^c3`�_a]-Z*_jc3h�`�b�U ]-ZsX �ad�[KZai�\�Z�] V�ds\�`�U0Z�V�X�b�c^`�U&X�`�\�VJU�`�djk�V�d X1U&SJS VJU*l \�]-Z�VNZ�hTiU*r�X�U*k�`�c^d huX4Z S"U SCS"U*k�Z&V�Z&`�U*]^_w

q `.h�d&e `J\�V�h�S.d \�`�`Jb�Z�`Y`Jb�c-SCc3h�Z&Q�c3]^c3`�_o�Z&`v]^U&Z S�`Rc^h�`�b�U0X*Z S�U6d�[KV�U&Zsi�c3h�lm`�U*r `�Z&]3ds\�i oeCZ S,S"c^tjk�]3_0i�\�U�`Jd �-��� G ���6$-�������3��I*���� [�Z X�`�d V�S���`Jb�Z�`,c-S1o c3tjk�]3U*taU*h`�Z&`�c^d h�Z&]�i�U*`�Z�c3]@SCzpS"\TX�bZ Sjk�Z�`J`�U*VJh U4h�X1d i�c^h�lS dsVuh�U*`�eFdsV � Z&V�X�b�c3`JU&X1`J\�V�U � `�bTZ�`uk�V�U4WU*h�`JU&iL`�b�U X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��SF]3U&Z&V�h�c^h�l6`�b�UYtuZ&k�k�c^h�lSD`�dmZ S�\��uX�c3U*h `Ci�U4l V�U4U�d�[,X�d tjk�U*`JU*h�X1_w

q `(c@S(c3tjk�d VJ`�Z&h�`(`JdYh�d `JUC`�b�Z&`F`�b�U*V�U.Z&V�UC`�eFdYc-SJS"\�U S eCb�c-X�b6b�Z*WUCQ=U X1d tjU,c3h `�U*VJ`�eCc3h�U&ib�U*V�Uxf eCb�U*`�b�U4VDZYX1d h�h�U&X1`�c^d h�c@S"`(h�U*`�eFd V�� c@S(Z�Q�]^UR`Jd $-5R���3��5 ����� �\�ZsS"c3VJU*l \�]-Z�VDtuZ&k�k�c^h�lS�oZ�h�i�eCb�U*`Jb�U*V�c^`Rc@S�Z�Q�]^U6`�d �3�J���� S"\�X�b�tuZ&k�k�c3h�lS1w q Z�t t Z�c3h�]3_uX1dsh�X1U*VJh�U&iub�U*V�U6eCc^`�b`�b�UR[OdsV�tjU4V(c-SJS"\�Uo Q�\�`,c3`FbTZ SF`�b \�S([�Z�VFk�V�d&WU*hj`Jd Q�U�\�h�VJU&S"ds]3WsZ�Q�]3U�eCc^`�b�ds\�`.X1d h [OV�d h `�c^h�l`�b�U ]-Z�`J`�U*V4fCeFU bTZ WU0Z�`Yk�VJU&S"U*h `.h�djeCZ*_ud�[KX1V�Z [O`Jc3h�lj`Jb�U6h�U*`�e,d V � $ SCc3h `�U4V�h�Z&]AV�U*k�VJU&S"U4h��`�Z�`Jc3dsh�S Q _jb�Z&h�i o�Z&h�inS�djZ&V�U VJU*]3c@Z�h `Fdshn]3U Z�V�h�c3h�l6tjU X�b�Z&h�c-S�tuS `JdjX1VJU&Z�`JUY`�b�U*t i�\�V�c^h�l`�b�Ua`�V�Z�c3h�c3h�luk�VJd X1U&S�S�w���SYi�U4tjd h�S�`�V�Z�`�U i�Z�Q�d&WUoAU&S"`�Z�Q�]^c-S"b�c3h�lueCb�U*`Jb�U*V X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��Svb�Z*WUa`�b�UuZ&Q�c3]^c3`�_n`Jd�c3tjk�]3U*taU1h ` ��\�ZsS"c^V�U*ls\�]-Z&V tuZ&k�k�c3h�lSvbTZ S V�U ��\�c^V�U&i ��V�S"`��h�i�c^h�l `Jb�Z�`.X�d taQ�c3h�Z&`�c^d hjd&[D]3U&Z&V�h�c^h�l6k�VJd X1U&i�\�VJUo�k�Z&`�`�U4V�hnU4h�X1d i�c^h�ljZ&h�i h�U*`�eFd V��jZ&V��X�b�c^`�U&X�`�\�VJU.S"\�X�b `Jb�Z�`,`�b�U i�U&S"c^V�U&i6tuZ&k�k�c3h�l G ��B� Q�U�]^U&Z�VJh�U&i w � b�c-SDc-S(eCb�Z�` ! ]-Z�\�`CZ�hTi$ X�D]3U*]^]-Z&h�inz�{4| |s}��,b�Z*WU �Th�Z�]^]3_uZsX�b�c^U*WU&i w

� b�c-SCZ�Q�c3]3c^`�_6b�Z SF`Jb�\�S9[�Z&VCd h�]^_ Q�U*U4huS"\�X4X1U&S�Sp[O\�]3]^_ji U*tjd hTS"`�V�Z�`JU&i d hudsh�UYS"c^tjk�]^c ��U&iX1d lsh�c3`Jc3WUj`�Z S � w �Rd&eFU*WU*V4o(c3`6b�ZsSEQ�U*U4h Z�VJl \�U i `�bTZ�`a`�b�U�X1dsh�h�U&X1`Jc3dsh�c-S�`aZ�k�k�VJdZsX�b c-S]3c �U4]3_#`�d#\�]3`Jc3tuZ&`�U*]^_#S"\�X*X�U*U&i c^h ds`�b�U*VmX1dsl h�c^`�c3WUu`�Z S ��SjZsSEe,U*]3]Yz &U*c-i U*h�Q�U*VJl�o�{4| |�����w��i�i�c^`�c3dsh�Z�]^]3_o,`�b�U�eCc-i�U&S�k�V�U Z i Z�k�k�]3c@X*Z�`Jc3d h ) Z&h�i S"\�X4X1U&S�S') d&[ h�U*\�V�Z�]�h�U4`"e,d V���S6c3h

Page 52: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �����\� � � ��V���� �����[�����O� � � |

h�d h���X1dsl h�c^`�c3WUak�VJd Q�]^U*t i�d t Z�c3hTS `Jb�Z�`0X1d h `�Z&c3h#V�U*ls\�]-Z&V�c^`�c3U SvZ&h�i:U*r�X1U*k�`�c3dsh�S6zpS�\�X�b Z SS"`�d X � t Z�V �U4`Ak�V�U&i c-X1`Jc3d huz P�c3tjds`�d � ��SJZ"�sZ*eCZ o={4| |s~ � $ X�D]3\�S �U*_o {*| |s}�� Z�h�iaZ�VJ`�c �=X1c-Z&]U*r�X�U*k�`�c^d h6`�Z S ��SRz y \�]3]^c3h�Z&V�c@Zf� Db�Z&`�U*V4o={4| |s}����De,d \�]@i Z&]-S�d Z&k�k�U&Z�VC`Jd S"\�k�k�dsV�`CS�\�X�bjZ&hZ�V�ls\�tjU*h `*w

����� � � � � � � ��� � � � ��� � ��� � � �

q h S"\�tmtuZ�VJ_o `Jb�U*hAoFc^` bTZ S6h�d&e Q�U*U4h U&S�`�Z�Q�]3c-S�b�U&iL`�bTZ�`uX1dsh�h�U&X�`�c3dsh�c-S�`6h�U*`�eFdsV ��S Z&V�UZ�Q�]^Uj`�d�c^tjk�]3U4t U�h�`NX1dstjk�]3U4r �\�Z S�c3V�U4l \�]@Z�V6tuZ&k�k�c3h�lS1o�Z�k�kTZ�V�U4h�`J]3_#`�d�`�b�UuS�Z&tjU ]^U*WU*]d�[�k=U4V"[Od VJtuZ�hTX1UYZ SCb \�tuZ�hTS1o�Z&h�i eCc^`�b�ds\�`.Z�h _jU*r k�]^c-X1c^`Fi \�Z�]AVJd \�`JU Z&V�X�b�c3`JU&X1`J\�V�U�Q�U*c^h�lV�U��\�c3VJU&i `JdjZsX�b�c^U*WU.`�b�c@S1w

� b�U�c3h�U*W c3`�Z�Q�]^U ��\�U S"`�c^d h `Jb�Z�` [Ods]3]^d�e.S6[OV�d t `�b�c@S V�U S"\�]^` c@S1f:h�d�e `Jb�Z�`jQ�ds`�b Z�k��k�V�dxZ X�b�U&SvbTZ WUaQ�U*U*h S�b�d&eCh `�dnbTZ WUm`�b�UmX*Z�kTZ X1c^`"_�`Jd�c3tjk�]3U*taU*h` ��\�ZsS"c^V�U*ls\�]-Z&V6tuZ�k��k�c3h�lxS1o�eCb�c@X�bmc-SF`�b�UvQ�U*`J`�U*V ��� � �� G � G �x$-�� � tjd i�U4]=d&[D`�b�U�b�\�tuZ�h �\�ZsS"c3VJU*l \�]-Z�V �%t Z�k�k�c^h�lS"_�S"`�U4t �

Dds]3`Jb�U&Z�VJ` t Z i�UDS�d tjUDk�VJd&Wd X*Z�`Jc3WU,X1d tmtjU*h`�S�dsh `�b�c-SAc-S�S�\�U,Z�`�ZRV�U X1U*h `AS"_ tjk�dS�c3\�tz Dd ]^`�b�U Z�V�`4oA{*|s|]&Z��w �.UYS"k�U&X1\�]-Z�`JU&ij`�b�Z&`C`�b�U4V�UYtuZ*_6Q�U tuZ&h�_6k�dSJS"c^Q�]3U�[O\�h�X�`�c3dsh�Z�] Z&V��X�b�c^`�U&X�`�\�VJU&S X4Z�k�Z&Q�]3U.d�[ tuZ�k�k�c3h�l�`JU*r `9`Jd S"k�U*U&X�bAo d&[ eCb�c-X�b6`�b�U.i \�Z�] V�d \�`�UNZ�V�X�b�c^`�U&X1`J\�V�Uc-SFd h�Uo Z&h�i `Jb�Z�`Nc3tjk�]^U*taU1h `�U&i6Q _jh�U*\�V�Z�]Ah�U4`"e,d V���S.Z�h�ds`�b�U4V*w q `CeCZsS�Z�VJl \�U i `�bTZ�`.`�b�Ui�\�Z�]�VJd \�`JURtjd i U*]�c@SDZvS�\�k�U*V�c^d V ��� � �� G � G �$-�� � tjd i�U4]�Q�U&X*Z&\�S"U.c3`Db�ZsiEQ�U*U4hjX1dsh�S"`JV�\�X�`�U&iQ�_uk�S�_�X�b�d ]^d lsc-S"`�S�Z [O`JU*VYX*Z&V�U1[O\�](X1dsh�S"c@i�U*V�Z�`�c^d h�d�[Cb \�tuZ&huV�U&Zsi�c3h�l i�Z�`�Z zOUw l�w3o�k�Z&`�`JU*V�h�Sd�[0i�_�S"]3U4r�c@Z�oCk�V�dsh�\�h�X1c-Z&`�c^d h ]-Z&`�U*hTX1c3U&S���oFeCb�c3]3U�`�b�U#X�d h�h�U X1`�c^d h�c@S"`jtjd i U*]CeCZsS S�c3tjk�]3_i�U*`�U4V�tjc^h�U&inQ _L`�b�U X*Z�k�VJc-X1c^d \�S k�V�d X1U&SJS d�[Nl V�Z i�c^U*h�`ai U&S�X1U4h�` c3h Znt \�]3`�c �pi c3taU*h�S"cBdsh�Z�]eFU*c^l b `��OU*V�VJd V.S"kTZ X1Uaz Dds]3`Jb�U&Z�VJ`*oA{4| |]&xZ���w

q h�Z6V�U&S�k=dsh�S"Umz y Z � �U*V4o {4| |]& ��o q Z&V�l \�U&i `Jb�Z�`.tjd i�U*]@S9d&[Db�\�tuZ�huX�d l h�c3`�c^d h�S"b�d \�]@ih�d `�Q=U ��\�i�l U i d h `�b�U*c3V # dsV�c^l c3hTS�$Yz%c�w Uw^oR`�b�UL`�U&X�b�h�c ��\�U&S Q _ eCb�c@X�b `�b�U*_ eFU*VJULX�d h��S"`�VJ\�X1`JU&i=��o,Q�\�`aV�Z�`Jb�U*VjeCc^`�b V�U&S�k=U X1` `JdL`�b�U*d VJU*`�c@X*Z�]^]3_#c3tjk�d VJ`�Z&h�`mZ�`J`�V�c^Q�\�`JU&S S�\�X�b Z Sk�Z�V�S"c3tmd h _o�X1d tmk�\�`�Z&Q�c3]^c3`�_o Z�hTinU&S"k�U&X1c@Z�]^]3_j`Jb�U6Z&Q�c3]^c3`�_j`�dmV�U*k�VJd i�\�X1U0Z�h�inU4r�k�]@Z�c^hnb \��tuZ�h k�U*V"[OdsV�tuZ&h�X1U�i�Z&`�Z�w q [ `�b�U�X1dsh�h�U&X1`Jc3dsh�c-S�` tjd i U*]Ci�U4tjd h�S�`�V�Z�`�U S6S"\�k�U*VJc3d VJc3`�_Ldsh`�b�U&S�U�X�V�c3`JU*V�c@Z z%eCb�c-X�b6c-S(_U*`D`�dYQ�U�i U*`�U*VJtjc3h�U&i=��o&`�b�U*h c^`Dc-S(`�d Q=U.k�VJU1[OU*V�VJU&i6Z S,Zvtjd i U*]poi�U&S"k�c3`�UN`�b�UYtjd i�U4] $ S,X1d tmk�]3U*raZ&h�inS�d tjU4eCb�Z�`Cdsk�Z��\�U lsU*h�U&S�c-S�w

Page 53: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

} ~ ������������ � �����\� ���O�������������O�����[� ����� � � ����O�

�.h�d `Jb�U*VFdsQ���U&X1`Jc3d ha`�bTZ�`CeCZsS9V�Z�c-S�U&inz y Z"�#�U*V*o�{*|s|]& �,X1d h�X�U*V�h�S Dd ]^`�b�U&Z&V�` $ SRzJ{*|s|]&Z�Z�k�k�Z&V�U*h `�Z S�S�\�tjk�`Jc3dshv`Jb�Z�` `�b�U [O\�h�X1`�c^d h�Z&] Z�V�X�b�c^`�U&X�`�\�VJU(c3tjk�]3U*taU1h `�U iFQ�_YZ.X1dsh�h�U&X1`Jc3dsh��c-S"`Yh�U4`"e,d V��neFds\�]-i�h�U&X�U&S�SJZ�V�c^]3_�i�c � U4V [OVJd t `Jb�Z�` S"k�U&X�c ��U&i�Q _n`�b�Uji�\TZ�]DV�ds\�`�Ua`�b�U4d V�_xw� b�c3]^UnX�d h�h�U X1`�c^d h�c@S"`6tjd i�U4]-Svt Z _#Q�U $-5R���3��5 �������J� i c � U*V�U4h�`J]3_oDZ&h�i i�U4`�U*VJtjc3h�U i Q _i�c � U*VJU*h�`,tjU&Z&h�S1o `�b�U*VJUYc-SFh�ds`�b�c^h�l `Jb�Z�`.]3dsl c@X*Z�]^]3_ak�V�U&X�]3\�i�U S9`�b�U*t [OV�dst c3tmk�]3U*taU*h `�cBh�lZji�\�Z&](V�ds\�`�U [O\�hTX1`�c^d h�Z&]DZ�V�X�b�c^`�U&X�`�\�VJUo Z&]3`Jb�d \�lsb:`Jb�c-SCk�dSJS"c3Q�c3]3c^`�_ c@SRV�Z&V�U*]^_�X1d h�S�c-i�U4V�U&iS"U*VJc3d \TS"]3_mc3hj`Jb�UY]3c3`JU*V�Z&`�\�VJUw

�NS `�b�U�k=U4V�X1U*c^WU&i ���� �3�3��� ��� d&[Y`�b�U #HX1d h�h�U&X1`�c^d h�c@S"`0X�b�Z&]3]^U*h�l U�$ `�d#`�b�Uni \�Z�].V�ds\�`�U`�b�U*dsV�_ b�c3h�lsU&S6d h `�b�c@S ZsS�S"\�tjk�`�c^d hAoCc^` eKZ�V�V�Z�h `�S [O\�VJ`�b�U*VaU*r�Z�tjc^h�Z�`Jc3dshAw � i�U*`�Z&c3]^U&iX1d h�S�c-i�U4V�Z�`Jc3dsh d&[D`�b�c-SFc-SJS"\�UYc@SFk�V�U&S�U*h `�U&i c^hu`�b�U�[Od ]^]3d&eCc3h�laX�b�Z&k�`�U4V*w

Page 54: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����� �

� � � � �� � � � �� � � � � � � � � �

� � � � � � �����

� ��� ��� � � ���� ���� ��

q h�`Jb�U6k�VJU*W�c^d \�S.`"e,duX�b�Z�k�`JU*V�S�o q b�Z*WU6V�U*W c3U*e,U&ij`�b�U �� � �D� G ����� Z�h�i�`�b�U G ���=�J1��$ G � �$ ��� Z�k�k�VJdZsX�b�U S `�dnU4r�k�]^c-X*Z&`�c^h�lj`�b�U c^tjk�]3U4t U*h `�Z&`�c^d hnd&[ ��\TZ S"c^V�U*ls\�]-Z&VYtuZ�k�k�c3h�lxS1w � b�Ui�\�Z�]CVJd \�`JUu`�b�U*dsV�_ S�`�Z&`�U&S6`�b�Z&`6b�\�tuZ�h�SY\�S"Uu`�eFd#i c-S"`Jc3h�X�` tjU&X�b�Z&h�c-S�tuS [Od Vab�Z&h�i�]3c^h�lV�U*ls\�]-Z&V�Z&h�inU*r�X1U*k�`Jc3d huc^`�U*tuS�o�eCb�c^]3UY`�b�U6X1dsh�h�U&X1`Jc3dsh�c-S�`�ZsS�S"U4V�`�c^d h�c-S1o Z�k�k�Z�VJU*h�`J]3_o�`Jb�Z�`��\�ZsS"c^V�U*ls\�]-Z&VCtuZ�k�k�c3h�lxSCX*Z�huQ�U c^tjk�]3U4t U*h`JU&i eCc3`Jb�Z S�c3h�ls]3UY\�h�c(��U&ijtjU&X�b�Z�h�c-S"t�w

q h `�b�c@S(X�bTZ�k�`JU*V*o q Z i�i V�U&SJS `�b�U ��\�U&S"`Jc3d h6d&[�eCb�U*`Jb�U*V(`Jb�UCi c � U*V�U4h�X1UDQ�U*`�eFU*U*h `�b�U,`�eFdZ�k�k�VJdZsX�b�U S c@S�tjU*V�U4]3_uX1dxS"tjU4`�c-X � `�b�Z&` c@S1oAeCb�U*`Jb�U*V�`Jb�UjZ&k�k�Z&V�U*h `�]^_�c3h�i�c^W�c@S"c^Q�]3Uo�S�c3h�ls]3UV�d \�`�U6X�d h�h�U X1`�c^d h�c@S"`Ctjd i�U4] X1d h�X�U&Z�]@SCZ�hnc^tjk�]^c-X1c^`Fi \�Z�] V�ds\�`�U0Z�V�X�b�c^`�U&X1`J\�V�Uxw � b�c-SCc-SCZ&hc3tjk�d VJ`�Z&h�` �\�U&S�`�c3dsh `Jb�Z�`jh�U*U&i�S6`�d#Q�U#Z i�i�VJU&S�S�U&i `�d X1]@Z�V�cB[O_L`�b�Unk�dS�c3`�c^d h�Sad h Q�d `JbS"c-i U&SRd�[K`�b�Uai U*Q�Z�`JUf�eCc3`Jb�d \�`�V�U&S�d ]^W�c^h�luc3`*o ]3c3`J`�]^Uvk�V�d lsV�U&SJS X*Z&h�Q�U tuZsi�U dsh:`Jb�Ua`�Z S �d�[�i�U*`JU*V�tmc3h�c^h�lReCb�U*`�b�U4V9`Jb�UNi�\�Z�]�VJd \�`JU�`�b�U4d V�_6dsVCX1dsh�h�U&X�`�c3dsh�c-S�t k�VJd&W�c@i�U&S(`�b�U.Q�U*`�`JU*VZ X*X1ds\�h `Rd&[Fb \�tuZ&h ��\�ZsS"c^V�U*ls\�]-Z&VRk�VJd X1U&SJS"c3h�l�w � kn\�h `�c^]Ah�d&eYo=ta\�X�bjd�[,`�b�U6i�U*QTZ�`�U b�Z SQ=U4U*hLX�d h�i�\TX1`�U&i�d h#`�b�UjZsS�S"\�tjk�`�c^d h )�b�U4]-ind h Q=ds`�b S�c-i�U S d&[C`Jb�U c@i�U*ds]3d lsc-X*Z&]Di�c^W�c@i�U)L`Jb�Z�`a`�b�Uu`�eFd Z�k�k�V�dxZ X�b�U&S ���� [O\�h�i�Z&tjU*h `�Z&]3]3_#i c � U*V�U4h�`4o9Q�\�` VJU&X1U*h ` k�b�c3]3dxS"dsk�b�c-X4Z�]��\�U S"`�c^d h�SFbTZ WUYQ�U*U*huV�Z�c-S�U&ijV�U*lxZ�V�i�c3h�la`�bTZ�`.Z SJS"\�tmk�`�c^d hAw

� d�Zsi�i�VJU&S�S `Jb�c-SYc-S�S�\�Uo q Q�V�c^h�ln`Jd lsU*`�b�U4V6S"\�Q�S"`�Z�h `�c-Z&]Fk�\�Q�]3c@S"b�U&i#U*W�c@i�U*h�X�U 2 G � `�b�U

}�{

Page 55: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

}(� ������������ � ����� ���\� ����� � ��� � ���O���������������\� � � � ��� � ��� �������

U*r�c@S"`JU*h�X1U,d�[�Z i \�Z�]�V�ds\�`�UNZ�V�X�b�c3`�U X1`�\�VJUCc3hmX1d h�h�U&X1`Jc3d h�c-S"`Dh�U4`"e,d V���S�w g c^V�S"`4o`�b�U.`�_�k�U&S(d�[U*W�c@i�U*h�X�UF\�S�U&iE`Jd S"\�k�k�dsV�`D`�b�U.h�ds`�c3dsh d&[ ZYi�\�Z&]�V�d \�`�U.c3h6b \�tuZ�h6k�V�d X1U&SJS"c^h�l Z�V�U.Q�VJc3U ��_c3h `�V�d i \�X1U&i w � b�UCtjdxS"`�X1d h W�c^h�X1c^h�lRU4W�c@i�U*h�X1U,X1dstjU&S=[OVJd t G ���$3�p$-I��N�=����� G ��� � �� G � G ��� oZS�X1c^U*h�X1U,c3haeCb�c-X�b6c3h�[OU4V�U*h�X�U&S Z&Q�d \�`Ch�dsV�tuZ&]�Q�V�Z�c^hE[O\�h�X1`�c^d h�c^h�l Z�VJURtuZsi�UF[OV�dst k�Z&`�`JU*V�h�Sd�[ i�U"� X1c3`aS�b�d&eCh Q _ b�\�t Z�h S�\�Q���U&X1`�SEeCc^`�b Q�V�Z&c3h i�Z�tuZ&l Uw q `6c@SE`Jb�U*h c3h WU&S�`�c3lxZ�`JU&ieCb�U*`�b�U*VR`Jb�U*VJU c-SNS"c3tmc3]-Z&VCU*W c-i�U*hTX1U�[Od V�`Jb�U U*r c-S�`�U*hTX1UYd�[Ki�\�Z&](V�ds\�`�U&S.c3h#X1dsh�h�U&X1`Jc3dsh�c-S�`c3tjk�]^U*taU*h`�Z&`�c3dsh�S9d&[ ��\�ZsS"c^V�U*ls\�]-Z&VRtuZ&k�k�c^h�lS�w q `Cc@SK[Ods\�h�in`�bTZ�` �$ ��� G *$-� ��$ G ��� Q�U*`�eFU4U*hV�U*ls\�]-Z&V.Z�h�ijU*r�X1U*k�`Jc3dshjtuZ�k�k�c3h�lxS9b�Z*WU�Q�U*U4hui�U*tjdsh�S"`JV�Z&`�U&i c^hu]3U&S�c3d h�U&ijX1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��S��&`�b�Z&` � G � /1�3�K�$ ��� G *$-� �p$ G �� b�Z*WUDU*WU*h�Q�U*U*h�[Ods\�h�i c3hYdsh�UDk�Z�VJ`�c-X�\�]-Z&V(X*ZsS"U��sZ�hTi`�b�Z&`R`Jb�c-S�Th�i�c3h�l e,d \�]@i o=cB[DeFU Z&k�k�]3c^U&i `Jb�U6SJZ�tjU S�`�Z�hTi�Z�V�i�S�d�[DU*W c-i U*h�X1UY`�dah�U*`�e,d V ��SZ�h�iub�\�t Z�h�S�o�k�V�d&W�c@i�U ���p� G � ����� U*W�c@i�U*h�X�U [OdsV.Z�hnc^h�`JV�c^h�S"c@XRi�\TZ�] V�d \�`�UYc3h�X1dsh�h�U&X1`Jc3dsh�c-S�`h�U*`�eFdsV ��SF`�b�Z&hnb�ZsS Q�U*U*h�i�U4tjd h�S�`�V�Z�`�U iE[Od V.`�b�UYb \�tuZ&huX1d lsh�c3`Jc3WUYS�_�S�`�U*t;w

� b�c-SYS"\�VJk�V�c@S"c^h�lnVJU&S"\�]^`�]3U Z i�SY`�d�Z�h Z&k�k�Z&V�U*h ` X1d h \�h�i�VJ\�t�f�dsh�Ujta\�S"`.U*c3`Jb�U*VYX�d h��X1]3\�i UFd ha`�b�c-S(U*W c-i�U*hTX1UD`�b�Z&`FX�d h�h�U X1`�c^d h�c@S"`(h�U4`"e,d V���S � G c^tjk�]3U4t U*h `AZYi�\TZ�]�VJd \�`JU [O\�hTX��`�c3dsh�Z�] Z&V�X�b�c3`JU&X1`J\�V�U.d V4o�c [ d h�Uvt Z�c3h `�Z&c3h�S(`Jb�Z�`.`�b�U4_ji�d6h�d `*o�`Jb�Z�`.i d \�Q�]^U i�c-SJS"d X1c@Z�`�c^d h�Si�d h�d `Cc3tmk�]3_uz�Z�`.]3U&ZsS"`1�,Z6i \�Z�] V�ds\�`�U Z�V�X�b�c3`�U X1`�\�VJUw

q h�`Jb�U ��h�Z&](k�Z�VJ`Yd�[,`�b�UaX�b�Z&k�`�U*V4o q i�c@S�X1\�SJS�`�b�U ]3d lsc-X6Z&h�i:S�b�d VJ`�X1dstjc3h�lSRd&[Ci c-S�S�d��X1c-Z&`�c3dsh�S�ZsS ZjtjU&Z&h�S d&[.i�c@S�X1d&WU*VJc3h�lmc3h `�U*VJh�Z�]�S"`JV�\�X1`J\�V�Uxo Z&h�i�k�V�dsk=dxS"UuZ�zOk=ds`�U*h `�c@Z�]^]3_��tjd VJUFi U&X1c-S�c3WU(eKZ*_vd&[ i�U*`�U4V�tjc^h�c3h�l,eCb�U*`Jb�U*V�X1d h�h�U&X1`�c^d h�c@S"` h�U*`�eFdsV ��S c^tjk�]^U*t U4h�` Z�i�\TZ�]V�d \�`�Uo�`Jb�U*V�U4Q�_mS"U*`J`�c^h�l6`�b�U SJX1U*h�U�[Od V.S�c3ta\�]-Z&`�c^d h�SDc3hu`�b�U�[Ods]3]3d&eCc^h�laX�bTZ�k�`JU*V*w

� � � � � � ��� � � � � � ��� � ��� � � � ���

q hu`Jb�U6X1dsh�h�U&X�`�c3dsh�c-S�` �,i�\�Z�] V�ds\�`�U0i�U*Q�Z&`�Uo�`Jb�U*VJU Z&k�k�U&Z�V�SR`�daQ�U6Z&`R]^U&Z S�`Rdsh�U k�d c^h�`.d�[Z�l VJU*U*tjU4h�`4f `Jb�Z�`KX1d h�h�U&X1`Jc3d h�c-S"`Dh�U4`"e,d V���S,X*Z�hjQ�UYX�b�Z&V�Z X�`�U*VJc �*U&iaZ S �4$-� � �3� ��� G ��"� tjU&X�b��Z�h�c@S"tuS�o c3h X1d h `�V�Z S"`6`Jd�`�b�U i�\�Z�]CVJd \�`JU�Z�V�X�b�c^`�U&X1`J\�V�UmZ i Wd X*Z�`JU&i:Q _ Dds]3`�b�U&Z�VJ`6U*`6Z&]pwz�{*|s| }��w &\�X�bjZ&h dsk�c3h�c3d hab�ZsSFQ=U4U*h VJU*k�U&Z�`JU&i�]^_aZ�h�i U4r�k�]^c-X1c^`�]^_ S�`�Z&`�U&i Q�ds`�buQ�_aX�d h�h�U X��`�c3dsh�c-S�`�tjd i�U4]3U*V�S�z%Uw l�w3o ! ]@Z�\�` � $ X�D]^U*]3]@Z�h�i o {4| | } �IjCdS�U*h�Q�U*VJl�o({4|(C�C �+jC\�tjU*]^b�Z�VJ`W�$ X�D]3U*]^]-Z&h�i o {4|(C�h � &xU*c-i�U4h�Q�U*VJlW� $ X�D]^U*]3]@Z�h�i o{4|(Cs|�� Z&h�iv`Jb�U*c3V i \�Z�] �%VJd \�`JUCZ i WU*V�SJZ�V�c^U&Sz Dd ]^`�b�U Z�V�`CU4`.Z�]pw^oA{*|s| } � ! c3h �U4V*o {4| | {���w

�.d�e,U*WU*V4o d h eCb�Z�`mX1VJc3`�U4V�c-Z�Z�VJUnX�d h�h�U X1`�c^d h�c@S"`6h�U*`�e,d V ��S Q�U*c3h�l#X1]-ZsS�S"U i ZsS S�c3h�ls]3U

Page 56: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � �����[�����O���@��� ������� � ���� � � � } }

V�d \�`�UuS�_�S�`�U*tuS � � b�UuX1]@Z SJS"c �=X*Z�`Jc3d h eFd \�]-iLZ&k�k�U&Z�V6`JdnQ�UjQ�ZsS"U&iLd h `�b�UjU4r�`JU*V�h�Z&],Z�k��k=U Z�V�Z&h�X1UYd�[ S"\TX�buZ6h�U*`�e,d V �ad V4o�V�Z�`�b�U*V*o�`Jb�U ����� �4$-�� � S�`�V�\TX1`�\�VJUf `Jb�U*VJUvc@S9dsh�]3_ G ���R�&���d�[ c3h�k�\�`D\�h�c^`�S(`�b�VJd \�lsbueCb�c-X�b � �^� c3`JU*tuS(Z&V�U�k�V�U&S�U*h�`JU&i `�d `�b�U.h�U*`�e,d V � o Z�h�i G �=�R�&��� d�[X1d h�h�U&X1`�c^d h�S(d&WU*V(eCb�c-X�b `Jb�U*c3V�U*]3c@X1c3`JU&i ZsX1`�c^W Z&`�c^d h�SDt \�S�`(`�V�Z*WU*]po b�U*h�X1UC`Jb�U*V�U.ta\�S"` ��\TS"`Q=U.ZYS�c3h�ls]3UFVJd \�`JUw � b�U [Ods]3]3d&eCc^h�l �\�ds`�Z�`Jc3dshE[OVJd t &xU*c-i�U4h�Q�U*VJlYZ�h�i $ X�D]3U*]^]-Z�hTi z�{4|(Cs|���oeCb�U*V�UY`Jb�U*_jk�VJd k�dS�U6ZaX1d h�h�U&X1`Jc3d h�c-S"`,tjd i�U*] d�[DVJU&Z i c3h�laZ&]3d \Ti o=c@SFV�U*k�V�U&S�U*h�`�Z�`Jc3WUf

� �U*_ [OU&Z&`�\�VJU d�[ `�b�UYtjd i�U4]AeFUYk�V�dsk�dS"Uac-SF`Jb�U6ZsS�S�\�tjk�`Jc3d h�`�b�Z&`R`Jb�U*VJUvc@SZnS�c3h�ls]3Uo(\�h�c [Od VJt k�V�d X�U&i�\�VJU [OdsV6X1dstjk�\�`Jc3h�l�Znk�b�d h�ds]3d lsc-X*Z&]FVJU*k�V�U S"U*h `�Z��`�c^d h [OV�dst Z�h6d VJ`�b�dsl V�Z�k�b�c@X VJU*k�VJU&S"U*h `�Z&`�c^d h `Jb�Z�`Dc@S Z&k�k�]3c@X*Z�Q�]3UF`Jd�U*r�X1U*k�`Jc3dsheFdsV�i�SYZ�hTinh�d h eFdsV�i�SYZ S�e,U*]3]�Z S�V�U4l \�]@Z�V�e,d V�i�S1wjz &U*c-i U*h�Q�U*VJl � $ X�D]^U*] �]-Z&h�i oA{*|�C | o=kAw %��&%�

� bTZ�` S"\�X�b�Z&hLZ&k�k�V�Z�c-SJZ�]Dc-SCQ�ZsS"U&i�tuZ�c^h�]3_md h�k�b _�S�c-X*Z&](Z&`�`JV�c3Q�\�`�U&S.d�[C`Jb�U tmd i�U*] c-SX1]3U&Z&V�]^_jZ&k�k�Z�VJU*h `Cc3h�ZEVJU&X1U*h `CX�d tjtjU4h�`(t Z i�U�Q _ &U4c-i�U*h Q�U*V�l�f

� c3`Jbj`�b�U l &U*c@i�U*h Q�U*V�l0Z�h�i $ X�D]^U*]3]@Z�h�iuz�{4|(C |�MmAtjd i U*] c^hjb�Z�hTi o�b�d&eFU*WU4V*od h�U X*Z&h �&��� `�bTZ�`Cc3`.i dU&S h�d `*o�c^hj[�Z X1`4o�c3tmk�]3U*tmU1h `DZ�h _ `�b�c^h�l6]3c �U�`�b�UNV�\�]^U&Sd V6`Jb�Uj]3c@S"` d�[NU*r�X�U*k�`�c^d h�SYk�V�U4W�c^d \�S�]3_#U*h�W c-S�c3dsh�U&i wLz &U*c@i�U*h Q=U4V�l�o,{*|s|(��o,kAw{ {`^Ul c3`�Z&]3c@X*SFZsi�i�U&i�mO�

jCU&X1U4h�`J]3_o b�d�e,U*WU*V4oAS"dstjU6d Q�S�U*V�WU4V�S�b�Z*WU��\�U&S�`�c^d h�U&i�`�b�c-S�h�d `Jc3dshAo(ZsS � c3h�l�c [Ck�U*V �b�Z�k�SF`Jb�UYX1dstjk�]^U*r�c^`�_vd&[�Z6X1d h�h�U&X1`Jc3d h�c-S"`Dh�U4`"e,d V�� tuZ*_aX1dsh�X1U&Z&] Z�huc3h `�U*VJh�Z�] 24� ��1��$ G ��� �������$3���J1������� X1dsh�S"c@S"`�c^h�lLd&[ ta\�]^`�c3k�]3UaV�d \�`�U&Snz $ X�D]3dxS �U*_xo�{*|s|�{��'&]^U �&Z"� o�{4| |]& ��w g d VU*r�Z&tjk�]^Uo &]^U �&Z"�;z�{*|s|]& �Ch�d `JU&i f

� b�UYi�c@S"k�\�`�UYc-SDk�V�U&i c-X*Z&`�U&i dshu`�b�U�`�Z X1c^`CZsS�S"\�tjk�`�c^d hj`Jb�Z�`C`Jb�UY`�eFd tmd i�U*]-SZ�VJUjX1dstjk�Z&V�Z�Q�]3U6c3h#ZueCZ*_�`�bTZ�`YtuZ"�U SRS�U*h�S"Uad�[NX�d \�h `�c^h�lu`�b�U6h \�taQ=U4V�d�[V�ds\�`�U&S(c^h U&ZsX�baX4Z S"Uxw��Rd&eFU*WU*V4o�`Jb�U.S"d �pX4Z�]3]^U&i ��S"c^h�l ]^U ��V�ds\�`�U.d�[�&U4c-i�U*h Q�U*V�lZ�h�i $ X�D]^U*]3]@Z�h�iLzJ{*|�C |�� c-S Z X1`J\�Z�]^]3_#`�b�UmU*h�`Jc3VJUji�c@S"`JV�c3Q�\�`�U&i#k�Z�V�Z�]3]^U*]Dh�U*` �eFdsV � [OdsVReCb�c@X�bu`Jb�UYWU*V�_ac-i�U Z d�[,X1ds\�h `�c3h�l ��V�ds\�`�U S �ji�dU S h�ds`Rt Z"�UYX1]^U&Z�Vd V.i�c^V�U&X�`.S"U*h�S�UwCz &x]3U �&Z � o {*|s|]&�o�kAw�^s�

� b�UaX*Z�\�S�U d&[,`�b�UaX1dsh�[O\�S�c3d h Z�k�k=U Z�V�S�`Jd Q�Uo Z S�c-S�S�dud�[O`�U4h�`�b�UaX*ZsS"Uo Z tmc-S"t Z�`�X�bd�[C`Jb�U �3��I���� � d&[NZ�h�Z&]3_�S"c-S�\�S�U&i�`�d�i U&S�X1VJc3Q�U6U&ZsX�b S"_�S"`JU*t z�[OdsV ZjlsU*h�U*V�Z�],i�c-SJX1\�SJS"c3dshLd�[

Page 57: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

}]& ������������ � ����� ���\� ����� � ��� � ���O���������������\� � � � ��� � ��� �������

`�b�c@S c-S�S�\�UoDS�U*U $ Z�V�V4oR{4|(C�����w �C`6Z�k�b�_�S"c@X*Z�],]3U*WU4]9d&[Yi U&S�X1VJc3k�`Jc3dshAo(d h�U�X*Z&h i�U S�X1VJc3Q�UZLX1d h�h�U&X1`Jc3d h�c-S"`mh�U*`�eFdsV � S"\�X�b Z S &U4c-i�U*h Q�U*V�l Z�h�i $ X�D]^U*]3]@Z�h�i $ SaZ SuZLS"c^h�l ]^U�V�ds\�`�US"_�S"`�U4t�o ZsS�`�b�U*VJU c@S h�djd Q W�c^d \�S �����*�4$-�� � S"U*k�Z&V�Z&`�c3dsh:d&[,k�V�d X1U S�S"c^h�luV�ds\�`�U&S�w'�Rd&eFU4WU*V*oZ S $ X�D]^dS �U4_uz�{*|s|�{&�Fk�d c^h�`JU&ijd \�`4o�d h�U X1d \�]@ijU���\�c3WsZ�]^U*h�`J]3_0X1]-ZsS�SF`�b�U�b�\�tuZ�hjQ�V�Z�c^huZ SZ #HS"c3h�l ]3UNV�d \�`�U S"_�S"`JU*t $ Z�`.`�b�U SJZ�tjU�]^U*WU*]�d�[9i�U&S�X�V�c3k�`�c3dshAw

$ X�D]3dS �U*_�z�{*|s|�{&�Ck�V�dsk�dS"U in`�b�Z&`�i�\TZ�] V�d \�`�U6Z&h�inX�d h�h�U X1`�c^d h�c@S"`Ctjd i�U4]-S9Q�U0X1d t��k�Z�VJU&ijd h�Z6b�c^l b�U*VC]^U*WU*]�d�[ Z�hTZ�]3_�S"c@S1f

� b�Unc@S�S�\�Unc@S h�d `jeCb�U*`�b�U4V `Jb�U*V�Uuc@S S�d tjUu]3U4WU*]Fd&[ i�U&SJX1V�c^k�`�c^d h Z�`jeCb�c-X�b`�b�U &xU*c-i�U4h�Q�U*VJlYZ�h�i $ X�D]^U*]3]@Z�h�ijzJ{*|(Cs|���h�U*`�eFdsV � bTZ�h�i�]^U&S(eFdsV�i�SDZ�hTiEh�dsh��eFdsV�i�S eCc^`�b Z�S"c3h�l ]3UmtjU&X�b�Z�h�c@S"t�w�jRZ&`�b�U4V*o `Jb�U �\�U&S�`�c3dshLc-SYeCb�U*`Jb�U*V `Jb�Uh�U*`�eFdsV � oAeCb�U*h X�b�Z&V�ZsX1`�U*VJc �*U i�Z�` �3��I���� �;�����3��I*���� 2 G �a G ���$3��$-I��a����� G ��$��4$-� �w(w(w6ZsX*X1dstjk�]3c@S"b�U S dsV�`�b�d l V�Z�k�b _ �%k�b�d h�ds]3d ls_ X1dsh�WU*V�S"c^d hnc^h:`Jb�UaS�Z&tjU eKZ*_[Od VCe,d V�i�SRZ&h�i h�dsh�e,d V�i�S1w.z $ X�D]^dS �U*_o�{*|s|�{ o kAwD} | { l c3`�Z&]3c@X*SFZsi�i�U&i�mO�

P.hjeCbTZ�`F]^U*WU*]�S�b�d \�]-i `Jb�URtmd i�U*]-S(Q�UYX1dstjk�Z&V�U&i � � b�U.`�U4V�t #Bi \�Z�] V�d \�`�U�$c-S(tjU Z�h ``�dmi�U*h�ds`�U6Z 24������p$ G ��� � Z�V�X�b�c3`�U X1`�\�VJUo�h�d `YZ k�b�_�S"c@X*Z�]Adsh�Ujz Dd ]3`Jb�U&Z&V�`*o {*|s|]&xZ���wF�.U*`�U*V �tjc3h�c^h�l�eCb�U4`�b�U*VKZvh�U4`"e,d V��6c-S#HS"c^h�l ]^U �%VJd \�`JU�$ S"b�ds\�]-ijb�U4h�X1U.c3h Wd ]3WUKZ�huc3h WU&S�`�c3lxZ�`Jc3d had�[`�b�Uac3h `�U*VJh�Z�] S"`�VJ\�X1`J\�V�Ujd&[.Zuh�U*`�eFdsV �#Z�` $ Z�VJV $ S6zJ{*|(C���� � � � G �1$3�-��56$- ]3U4WU*]poAZ&h�i � G � ZS"c3tmk�]3U.U*r `�U*VJh�Z�] Z�k�k�V�Z�c@S�Z�]�wN.c^WU*h `Jb�U�c^h�`JU*V�h�Z&]AX1dstjk�]^U*r�c^`�_vd&[�X1d h�h�U&X1`Jc3d h�c-S"`,h�U*`�eFdsV ��S1o c3`Fc@S9]^U&S�SD`�b�Z&h dsQ�W c3ds\�S

b�d&e dsh�U�eFds\�]-i i�U*`JU*V�tjc^h�Uj`Jb�Un[O\�h�X1`Jc3dsh�Z�]NZ�V�X�b�c^`�U&X�`�\�VJU c^tjk�]^U*t U4h`�U&i [OdsVjb�Z&h�i�]3c^h�lV�U*ls\�]-Z&V�S�Z&h�inU*r�X1U*k�`Jc3d hTS1o�eCb�U*`Jb�U*V.`�b�Z&`�Q�UaZ0[OdsV�t d�[Ki�\�Z&] VJd \�`JU6d VNS"d tmU*`�b�c^h�lmX1d t��k�]3U*`JU*]3_ i�c � U*VJU*h�`4w q h�`�b�U6h�U*r�`NS"U X1`�c^d h q i c-S�X�\�S�S $-���$-���J1� tjU*`�b�d i�S d&[,U*]3\�X�c-i�Z&`�c3h�l6`�b�U[O\�h�X1`Jc3d hTZ�] Z�V�X�b�c3`�U X1`�\�VJURd&[,X1dsh�h�U&X1`Jc3dsh�c-S�`Ch�U*`�eFdsV ��S1w

� ��� ��� � � � � �� � � ��� � � � � � � � � � � � � �� � �

� b�Z�`DU*W c-i�U4h�X1UDc-S `Jb�U*VJUo `�b�U*hAo�[OdsV9`Jb�UCU*r c-S�`�U*h�X�U9d&[ Z [O\�h�X1`�c^d h�Z&]�i�\�Z&]�V�d \�`�UCc3haX�d h�h�U X��`�c3dsh�c-S�`�h�U*`�e,d V ��S�� �Rh#Z�hTZ�]3dsl _#X*Z&h�Q�Uai�V�Z*eCh�b�U*VJU6Q�U*`�eFU*U*h;X1d h�h�U&X1`Jc3d h�c-S"`.h�U*`�e,d V ��SZ�h�i `�b�Ujb \�tuZ&hLQ�V�Z�c3h w y d `�b S�_�S�`�U*tuS Z�VJUnZ&Q�]3Uu`Jd:]^U&Z�VJh Z�h�i c3tjk�]3U*taU*h `���\TZ S"c^V�U*l �\�]-Z&V tuZ&k�k�c3h�lS1oDZ&h�iLQ�d `�b Z&V�Uuc3h `�U*VJh�Z�]^]3_#S�d#X1d tjk�]3U*r�`�b�Z&`6W�c@S"\�Z&]Fc3hTS"k�U&X1`Jc3d h d�[N`�b�U

Page 58: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � �@�����@� � ��� ����@���� ��� � �O� � � � � � ��� ����� }&%k�b�_�S"c@X*Z�] Z�V�X�b�c^`�U&X�`�\�VJU�i�dU SFh�d `Ni�U*]^c3WU*V(\TS"U1[O\�]Ac^h�S"c^l b `�SDc3h `�d6`�b�U�h�Z�`J\�V�UYd&[(c^`�SFc3h `�U4V�h�Z&][O\�h�X1`Jc3d h�c3h�l�w

q h `Jb�U#X*Z S�U:d&[6`Jb�U�Q�V�Z&c3hAo.V�U&S�U&Z�V�X�b�U*V�SjZ&V�U�\�hTZ�Q�]^U:`Jd i c3V�U X1`�]^_LtuZ�h�c3k�\�]@Z�`JU�Z�hTiU*r�k�U*VJc3tjU4h�`.d h `�b�U e,d V���c^h�l�S�_�S�`�U*t�o�Z�h�i S�d�b�Z*WUjQ�U*U*h:[OdsV�X1U&i#`�d�V�U4]3_#d h c3h�i c3V�U X1`*oQ=U4b�Z*W�c^d \�V�Z�]CU*W c-i�U4h�X1Ujc^h VJU&Z S�d h�c^h�l Z�Q�d \�`a`�b�U [O\�h�X�`�c3dsh�Z�].Z&V�X�b�c3`JU&X1`J\�V�Uw q eCc3]3]Ch�d�eV�U*W c3U*e `Jb�c-SDU*W c-i�U*hTX1Uo Z�h�i�i�c-SJX1\�SJSFb�d&e c^`.X*Z�h�S"c^tjc3]@Z�VJ]3_ Q�UY\�S�U&ij`�d6V�U Z S"dsh�Z&Q=ds\�`.`�b�UU*r�c@S"`JU*h�X1U.d�[,i \�Z�]AVJd \�`JU&S c^h�X1d h�h�U&X1`�c^d h�c@S"`,h�U*`�eFdsV ��S1w

��������� ���� ������������������������� ��

�"!�#%$'&)(+*�$(�,#.-/$0!�#%$21�3'$2(�&.*�4657*�86!9&7!:$2(6-/$2;�&7#%*�<=&)*�4?>+-�!A@B>C;�;�&75C!9>C(�$2(�DE5GF6>H8�*.*�4�&IF�;J5G$'( $K!@B8�(6#%*�$'>C(L5G3M!N*�;�86#%*�8�;�&I$O!IPRQRSUT�V'WXVOYGZ[T\Z^]+_�Q%`�a � Pcb?QCdeQRS �=f &g465G323'$O#^&Uh�i)j�C(CUkRlnmo*p5G$'<q!A*�>n&)328��#%$O-�57*�&I$'(+*�&);�(65G3�!N*�;�86#%*�8�;�&IF/rE!9*�86-+r/$2(�Ds*�4�&t16&);9@B>C;�<n5G(6#^&.>G@�*�4?&t4+8�<n57(uF�;R57$'(v8�(L-/&);#%>C(6-+$'*�$2>C(6!�>7@w-?5G<n57DC&Ulyx�5G*�$'&)(+*R!wz�4�>{4L5}|U&q!N8 �,&);�&7-vF�;R57$'(~3'&7!9$'>H(�$'(�D f &Ul�D�l2h�*�4�;�>C8�DH4!N*�;�>C�U&7!^h\>H;�&)�+*�&);�(65G3�*�;J5G8�<q5�k�5G;�&p*�&7!9*�&7-�@B>H;A$2<=1657$';�<[&)(/*J!�$2(u#%>HDC(�$2*�$'|U&p57F�$'32$'*�$2&7!�!N8L#c45C!�<[&)<=>C;�rUh);�&}5C-/$2(�Dp5G3'>H86-�hU>C;M|U&);�F.$2(��6&7#^*�$'>H(�l���4?&�!9r/<=1?*�>C<q!�57(6-�32>+#)5G*�$'>H(6!�>7@�-�5G<��5GDC&�5G;�&�;�&}#%>C;J-/&7-I5C#%;�>U!�!�165G*�$'&)(+*R!^h+5G(6-�@B;�>C<�*�4�$O!�!N1L5G;R!9&w5G(L-t165G*�$'&)(+*��X!N16&7#^$ �,#�-�57*R5w*�4�&#%>CDH(�$'*�$'|U&s(?&)8�;�>H16!Nr?#R4�>C32>CDC$0!N*n&)(6-+&75)|U>C8�;J!t*�>~#^>C(6!9*�;�8L#%*nDC&)(�&�;R5G3�*�4�&)>H;�$2&7!t>C(�(�>H;�<n573#%>CDH(�$'*�$'|U&w!9*�;�8L#%*�8�;�&Ul

��4?&);�&n57;�&=*9zM>sF65H!N$O#I<=&)*�4?>+-�!�@B>H;.$'(+*�&);�1�;�&)*�$'(�D[165G*�*�&);�(6!�>G@�$'<=1L5G$';�<t&�(/*J!A!94�>7z�(F/rv1L5G*�$2&)(+*R!%l���4�& �6;J!N*I$'(+|U>C32|U&7!�DC;�>H8�1�$2(�D~#%>H<=<=>C(?3'rE#%> ��>+#)#^8�;�;�$'(�Dy!Nr+<=1�*�>C<n!w$'(+*�>!Nr+(6-/;�>H<=&7!^h/*�4L5G*�$O!^h�F/r[3'>U>C�+$'(?D�@B>C;��GaRa�QGP�VO�CWoVOQUT�aM>G@�!Nr+<=1�*�>H<n!%l

� >H;�&)�?5G<=1�32&Uh/$2*�<=$2DC4+*�F\&w@B>C8�(L-�*�465G*�$2<=1657$';�<[&%(+*R!�$'(s*J5C!9��!w��h,�5G(L-{�573'z�5}r?!>+#)#%8�;=*�>CDH&)*�4�&�;)h�3'&75H-/$'(?Dv*�>v*�4�&u4+r/16>C*�4�&7!9$O!t*�465G*=*�4�&)r�5G;�&�!N8�FL!N&);�|U&7-�F/r~*�4�&E!�57<=&f -�57<n5GDH&7-\k�5G;�&}5A>G@,*�4?&�F�;J5G$'(�l���*�4�&)>H;�&)*�$O#)573+-/;R5)z�F65H#c�p>G@6(�&�8�;�>H16!Nr?#c4?>C3'>HDC$0#)5G3+*�4�&�>C;�$2&7!F65C!9&7-=>C(�5C!�!N>+#%$05G*�$2>C(6!�$O!�*�465G*�*�4�&)r[5G;�&:|U&�;�r�]+T�a^Wo�U�^d'Z fN  4L5G3'32$O#%&gh\i�j(C�C�kR¡�*�4?&�-+$O!�#^>G|U&�;�r>G@�¢98L!N*�>C(�&�1657*�$'&�(/*�*�465G*�&)�+4�$2F�$'*J!�$'<=1L5G$';�<t&�(/*,$'(I*R5C!9�I�£5G(6-I��hCF�8?*�(?>C*���h+#)5G(.@X5G30!N$¤@Br>C;�¥�_��UP^WoVOQUT��CW9Z�!986#R4s5.4+r/16>C*�4�&7!9$O!%l

�¦<=>C;�&�16>7z�&);9@B8�3�<[&)*�4�>+-+>C3'>HDCrn$O!�*�>I;�&}#%>C;J-v§UV¤aRa�Q7P)VO�CWXVOQUT�a�F6&)*9z�&)&�(�*J5C!9��!^lA��-/$O!9¨!N>+#%$05G*�$2>C(E>+#)#%8�;J!:$e@�F?;R5G$2(v-?5G<n57DC&[#)5G86!9&7!w5�1657*�$2&)(/*�*�>n16&);N@B>H;�<©16>U>C;�3'rE>C(~5=*R5H!N�E�z�4�$'32&t<n57$'(+*R57$'(�$2(�D=(�&757;�¨B(�>C;�<n5G3 f >H;.5G*p3'&75H!N*�h�<t86#R4sF6&)*�*�&);^k�16&);9@B>C;�<q5G(6#%&I>C(ª5s*R5C!9�

Page 59: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� h ������������ � ����� ���\� ����� � ��� � ���O���������������\� � � � ��� � ��� �������

��l���4?$O!:1L5G*�*�&);�(y>G@�$'<[165G$2;�<I&)(/*�#)57(vF6&=$'(+*�&);�1�;�&�*�&7-s*�>u!N$2DC(�$e@Bru*�4657*�*J5C!N�?!.� 5G(6-v�5G;�&p!9&);�|U&7-=F+rn-/$ ��&�;�&)(+*�57;�&75H!�>7@�*�4�&wF�;J5G$2(�h\F6&7#�5G86!9&:*�4�&7!9&�57;�&75H!A57;�&�5GF�32&:*�>tF6&�-�5G<=¨5GDC&}-{$'(6-+&)16&)(6-/&)(+*�32rUl.��4�&�>C;�$2&7!�F65C!9&7-{>H(v-/$0!�!9>+#%$O57*�$'>H(6!�57;�&=<I86#R4s<=>H;�&p;�>CF?86!N*p*�4657(*�4�>g!N&IF65C!9&7-�>H(v5H!�!9>+#%$O57*�$'>H(6!%¡w*�4?&�@B8�*�8�;�&.>+#�#%8�;�;�&)(6#%&.>7@�!98�F�¢9&7#%*J!Az�$'*�4u|C57;�$05G*�$2>C(6!�>H(*�4�$0!�-/&��,#%$2*�165G*�*�&);�(��[*�4657*A$0!%h�z�$2*�4nF6>C*�4E�¦57(6-s�£$'<=1L5G$';�&7-��+>C;�*�4�&w;�&�|U&);R!9&�165G*�*�&);�(�hz�$'*�4ª� $'<[165G$2;�&7-u57(6-v��(�>C;�<n5G3��Ez�>H8�3O-u(�>H*.*�4�;�&75G*�&)({*�4�&=*�4�&)>C;�r{>H;�F6&n#)5786!N&I@B>C;;�&)¨X5G1�1?;R5G$0!�573ol��5)|/$2(�D�F6>C*�4s*J5C!N�?!�$'<=1657$';�&7-t#�5G(u!9$'<=1?3'r.F6&p-/8�&w*�>.*�4�&w165G*�$'&)(+*�465)|/$2(�D<=>C;�&�&)�+*�&)(6!9$'|U&�3'&7!9$'>H(�$'(�D?h/z�4�$23'&�L(6-/$'(?Dt*�4�&w;�&)|U&);J!N&�1L5G*�*�&);�(n>7@�$2<=165G$2;�<=&�(/*�$0!�5.!N16&)¨#%$O573�#)5H!N&�*�465G*�!N$2DC(�$��,#)5G(+*�32r=a^Wo_RZ^TCSCWOb6Z^T�a�*�4�&w&)|+$O-/&�(/*�$O5G36F65H!N$0!�@B>C;�*�4?&�4/r+16>C*�4�&7!N$0!%h65H!�$O!-/$O!�#%86!�!9&7-=F6&)3'>7zwl

��(�&�!N8�F�*�3'&�1?;�>CF?3'&)< z�$'*�4=*�4�&�$'(+*�&);�1�;�&)*J5G*�$'>C(I>G@�-+$O!�!9>+#%$O57*�$2>C(6!�$0!�*�4?&�16>U!�!9$'F�$23'$2*NrI>G@5~_cZ�a�QU]+_�P%ZI�U_RWXV ¥��UP%W fN  465G323'$O#^&Uh�i)j� � �kJl~��465G*.$0!%h�*R5H!N�?!.� 5G(6-~��#%>H8�3O-�h�-+&7!N1�$2*�&=*�4�&)$2;-/$O!�!N>+#%$05G*�$2>C(�h�F6&=!98�F6!N&�;�|U&7-uF/ru*�4�&[!�5G<[&I5G;�&}5C!:>7@�*�4�&tF?;R5G$2(���$'<[165G$2;�&7-n1\&�;N@B>C;�<n5G(L#%&>C(v*J5C!N�y� <[$'DC4+*w!9$'<=1�32rsF6&n-/8?&t*�>s*�4?&t@X5C#%*w*�465G*p$'*w$O!w<=>C;�&I-/$��q#%8�32*:*�465G(y*R5C!9�v�pl� >H;A&���57<=1�3'&gh�$e@�*R5H!N���£z�&);�&�*�4?&�#^>C<=1�;�&)4�&)(L!N$'>H(n>G@M57F6!N*�;R5C#^*�z�>H;R-�!^h�57(6-�*J5C!N���*�4�&#%>C<=1?;�&)4�&�(6!N$2>C(s>7@�#%>C(6#^;�&)*�&�z�>H;R-�!^h�*�4�&I-/$0!�!9>+#%$O57*�$'>H({F6&)*9zM&)&)(u57F6!N*�;R5H#%*p5G(6-E#%>C(L#%;�&)*�&z�>C;J-t#^>C<=1�;�&)4�&)(L!N$'>H(.#%>H8�3O-�(?>C*�1?;�>C16&);�3'rpF\&�86!9&7-�*�>w$'(+@B&);�*�4L5G*M#%>C(L#%;�&)*�&�5G(6-I5GFL!N*�;J5C#%*z�>C;J-�!�;�&��U8�$';�&�5:-+$ �,&);�&�(/*�!9&)*�>7@�1�;�>+#%&7!�!N$'(?D.!Nr?!N*�&)<n!��U5G(EQUY7Z^_��Cd2dC;�&7-+86#%*�$2>C(I$'([#)5G1L5C#%$2*Nr<n5)ru!N$2<=1�32rs465)|U&I<n5C-/&I57F6!N*�;R5H#%*.z�>H;R-/¨B465G(L-/3'$2(�Ds$2<=16>U!�!9$'F�32&Uh�z�4�$'32&=!9*�$23'3�16&);�<=$2*�*�$'(�D;�&75H!N>C(L5GF�32&�16&);N@B>H;�<n57(6#%&�>H(�#%>C(6#^;�&)*�&:zM>C;J-�!%l

� <I86#R4n<=>C;�&.#%>H(/|+$'(6#^$'(�DI165G*�*�&);�(u>G@�!Nr+<=1�*�>H<n!�$O!�*�4�&�§UQU]+�%d'Z[§UV¤aRa�Q7P)VO�CWXVOQUT/h��6;J!N*-/&7!�#^;�$'F6&7-EF/rE��&)8�F6&); f i)j�����kJl{� -/>C8�F?3'&n-/$0!�!9>+#%$O57*�$'>H(~$O!�-+&��6(�&7-E*�>u&)�+$O!9*:$e@�>C(�&[165G¨*�$'&�(/*w465H!t5u-/$0!�!9>+#%$O57*�$'>H(~z�4�&);�&�F/rE16&);N@B>H;�<n57(6#%&I>C(�*J5C!9�~�"$O!w$'<=1L5G$';�&7-E5G(6-v*R5H!N�~�$O!�(�>H;�<n573oh�z�4�$23'&�5G(�>H*�4�&�;t1657*�$2&)(/*p465C!.*�4?&�>H1�16>U!9$'*�&g¡s*R5H!N�~��$O!�$2<=165G$2;�&7-y5G(6-~*R5C!9��"$O!�(�>H;�<n573olu��4?&�$2<=1�32$O#)57*�$'>H(u$O!^h�>G@�#%>C8�;J!N&Uh�*�4L5G*.*R5H!N�~� 5G(6-~��;�&��U8�$';�&=-+$O!N*�$'(6#^*6�1�;�>+#%&}!�!N$2(�DI!Nr?!N*�&)<n!^hC>G@�z�4�$O#R4I>C(�32rt>H(�&�465H!�F\&�&)(n-�57<n5GDH&7-t$'([&)$'*�4�&);�165G*�$'&)(+*)l��A>C8?F�3'&-/$O!�!N>+#%$05G*�$2>C(6!M#%>C(L!N*�$2*�8�*�&A16>7z�&�;N@B8�36&)|+$O-/&�(6#%&�F6&7#)5786!N&�*�4�&)rI#)57(�(�>H*�F6&�&)�+1�3O57$'(�&}-�F/r.;�&)¨!N>C8?;R#%&�5G;�*�$¤@X5H#%*R!^h65G(6-�#)5G(�F\&p86!N&}-�*�>[#%>H(6!N*�;�86#%*�*�4?&)>C;�$'&7!�>H(sF�;J5G$'(n@B8�(6#%*�$'>H(65G32$'*9rt*�465G*

! �[=>( 0HD�G�2@079G<$HA 243M7 $'=;3M$�0-F;)-= 19&'G9)+2@0-0'(/798 0-.�0'$'2�A 0H=;3T_I2�$'G�Q 2L)#GIA 1>, 2�$'2@,/.�(/7;D�2@1 2@7;D�2�7]$ � GI79,/.$-=;36$�$-=92@. 243<)'= =;3T_I2 36$V,/24360-$�GI792 D%( 0-$'(/7;)+$�)+GIAV1;G<792@7�$�$'=;3M$ $'=>2 GI$-=92@& 0-.�0'$'2�A D�G�2@0 79G<$ &-2@,/.�GI7Uc"�=;3M, ,/(*)+2I: � ����IZ@b

Page 60: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ����� �[� ���@�������������@� ���O���������������\� � � ������� �O� � � ���

5G;�&p(�>C*�-/&)|H573'8�&7-=F+rn5G(+r=>HF6!N&);�|U&7-s573'*�&);�(657*�$2|U&�16&);�<I8�*R57*�$2>C(6!�>7@�*J5C!N��5H!�!N>+#^$O5G*�$'>H(6!�>C;-/$O!�!N>+#%$05G*�$2>C(6!^l

� &)*�8�;�(�$2(�D=*�>�*�4�&.-+865G3�;�>H8�*�&.*�4�&)>H;�rUh�-+>C8�F�32&I-/$O!�!N>+#%$05G*�$'>C(L!�>HF6!N&�;�|U&7-s$2(u165G*�$'&)(+*R!��1�;�>+#%&}!�!N$2(�Dn>G@�&)��#^&)1�*�$2>C(�z�>C;J-�!w5G(6-u(�>H(/zM>C;R-?!�4L5}|U&pF6&)&)(E86!N&7-u5H!�1�;�$2<n5G;�r�&�|/$0-/&)(6#%&$'(E!N8?1�16>C;�*p>G@�*�4�&I-/8L5G3�;�>H8�*�&.*�4�&)>C;�ru>G@M;�&}5C-/$2(�D�5G3'>H86- f ��>C32*�4�&}5G;�*w&)*�5G3ol2h�i)jHj � kw5G(L-165C!9*�¨B*�&)(6!9&�DH&)(�&);J5G*�$2>C( f x�$2(��U&);)h,i)jHj/iGkJl

mo( *�4�&E#)5H!N&�>G@p;�&75H-/$'(?D~5G32>C86-�h�>+#)#%8�;�;�&)(L#%&7!.>G@pF6>C*�4£`�b?QUT?QCdeQRSUVOPR�Cd�-+r�!93'&)�+$O5 f *�4�&$'(657F�$'32$'*9r�*�>�;�&75H-�(�>C(+z�>H;R-�!�z�4?$'3'&M;�&)*J5G$2(�$'(�D�&)�?#%&)1�*�$'>H(6!��U��&}5G8�|U>H$O!�� ��&�;�>C8�&7!N(�&gh�i)j � j �� 8?(�(�&)323oh+i)j� � k�5G(L-ta�]/_'¥��UP%Z�-/r?!N3'&��/$05 f *�4�&M$'(657F�$'32$'*9r�*�>�;�&75H-�&)��#^&)1�*�$2>C(6!�z�4�$23'&�;�&)*R57$'(�$2(�D(�>C(+z�>H;R-�!����u5G;R!9465G323��� A&�z�#%>H<tF6&Uh�i�j � � �   4L5G3'32$O#%&gh��y5G;�;�$2(�DC*�>C(�h����u#G�M5G;�*�4+rUh�i�j� � k465)|U&A&7!9*R57F�3'$0!N4�&7-I5�-+>C8�F�32&w-/$0!�!N>+#^$O5G*�$'>H(=$'(=;�&75C-+$'(�Dp*�4657*�$'<[1�3'$2&7! *�4�&�&)�+$O!9*�&)(L#%&�>G@�-/8L5G3<=&7#R465G(�$0!N<n!�@B>C;�465G(6-+3'$'(?D.(�>C(+z�>H;R-�!�5G(6-n&)�?#%&)1�*�$'>C(L!�z�>H;R-�!^l

� !9$'<=$23O5G;w1657*�*�&);�( 465C!.F6&)&)(v@B>C8�(L-�$'(~*�4�&s165H!N*I*�&)(L!N&n*R5H!N�,l�x�57*�$2&)(/*J!:z�$2*�4  �� mf�� `6Z�P)V �MP����UTCSg]/�)S/Z����A`?�UVO_��tZ^T/WOkA4L5}|U&[-/$��n#%8?3'*�$2&7!�$'(vDH&)(�&);J5G*�$'(�D�;�&)DH8�3O57;�165H!N*.*�&�(6!N&@B>C;�<q!%h�z�4�$'32&=&)�+4�$'F�$2*�$2(�Du(�&757;�¨B(�>C;�<n5G3�16&);9@B>C;�<q5G(6#%&[>C(�&���#%&�1�*�$2>C(~z�>H;R-�!��A57(6-�h�#^>C(�¨|U&);R!9&)3'rUh��sV'd2deVO���:a ��� T�§U_�Q��tZ�1L5G*�$2&)(+*R!�$'(6#^>C;�;�&7#%*�3'rw$'( �L&7#%*�&)�?#%&)1?*�$'>H(.z�>H;R-�!^h�-/$0!N1�305}r+$'(?D5�*�&)(6-/&)(L#%rt*�>.>7|U&);�;�&)DC8�305G;�$"!)&�*�4�&)< f x�$'(?�U&);)h,i)jCj+iGkJl

��!�(�>C*�&7-:$2(���4L5G1�*�&);$#+hG*�4�&7!9&�1657*�*�&�;�(6!�>G@?$'<=1L5G$';�<=&)(+*6#%>H(6!N*�$'*�8?*�&M!N>H<=&�>G@?*�4�&M<=>U!9*!�5G32$'&)(+*w57(6-{#^>C(+|/$2(6#%$'(?D=&)|+$O-/&)(L#%&:@B>H;:*�4�&[-/865G3�;�>C8�*�&t*�4�&)>C;�r � ��$'(6-+&)&7-�h�*�4�&I(65G$0!�!�57(6#%&>G@M*�4�&�-/86573�;�>H8�*�&p*�4�&)>H;�r�>G@M;�&75H-/$'(?D=#)57(uF6&.*�;R5H#%&7-n*�>=165716&);R!�!986#R4E5C!%�u57;R!N4L5G3'3�5G(L- A&)z�#^>C<IF\& f i�j ��� kRh�z�4�&�;�&�*�4�&�$0-/&75�>G@�*9zM>.!N&�165G;J5G*�&�1�;�>+#%&}!�!N&}!�@B>C;M1�;�>H(�>C8?(6#%$'(?D�z�>H;R-�!z�5C!�$2(�$'*�$O573'3'rp1�;�>H16>U!N&}-�h��R�Ga7Z�§A>C(n1657*�*�&�;�(6!�>G@�$'<=1657$';�<=&%(+*�$'(=F�;J5G$2(�¨o-?5G<n57DC&7-t1L5G*�$2&)(+*R!*�4657*�-/$'&,&);�&)(+*�$05G323'rI5(&,&7#^*�&7-=16&);N@B>H;�<n57(6#%&�>H(s;�&)DC8�305G;�57(6-�&)�?#%&)1?*�$'>H(=z�>H;R-�!^l

� ��� � ����� ��� � � ��� �� � � � )+*��-,/.10324*�5276�098 ,:0<;9*�=��>6

mX@,zM&�&)<=1�32>Gr�*�4�&�!�57<=&�(�&�8�;�>H16!Nr?#c4?>C3'>HDC$0#)5G36*�&}#c4�(?$ �U8�&7!�*�>w&)�?5G<=$2(�&�165G*�*�&);�(6!�>G@�-+&��,#%$2*$'(£-?5G<n57DC&7-£#%>H(�(�&7#^*�$'>H(�$O!9*t(?&)*9z�>C;���!^h�4�>7z <I86#R4~&���8?$'|H5G32&)(/* f $2(6-/$2;�&7#%*^kw&)|+$O-/&)(L#%&n$O!*�4�&);�&=@B>C;.*�4?&s&)�+$O!9*�&)(6#^&t>7@p5{-+865G3�;�>H8�*�&n$'( #%>H(�(�&7#^*�$'>H(�$O!9*I!Nr?!N*�&)<n!:*�465G*I$'<[1�3'&)<[&%(+*

?A@CB7DFEHGIG �KJ4J7LNMPOAQ�RTS�UFVXWYLNZ\[YV^]_]a`'bPG:McOAQTR�RTUedfJ�ghL\`aEcbiB7EHEj`_JTW7EhJ�WNDH[7G%Dj[7GIJ�gjGIDH`'bIV^]�klGAVXm\W7G�EHEHG�E1JXd`aW\d"GIgHGIWnbPGIE�L(gcVok<WpdfgHJTqr]aGIEH`aJTW7`aW7stG �(unGIgj`_qpGIW\DHEov

Page 61: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ������������� ����������������� ��� ����� � ����������� � ������� �"!���# � � !������

��865H!N$2;�&)DH8�3O57;A<n571�1�$2(�DU!%$E� >q5C-�-/;�&7!�!�*�4?$O! ��8�&}!N*�$2>C(�h,!N*�86-/$2&7!�z�$23'3�(�>7z¦F6&�;�&)|/$2&)z�&}-t$'(z�4�$O#R4w*�4�&M1\&�;N@B>C;�<n5G(L#%&�>G@632&7!N$2>C(�&7-w(�&)*9z�>H;��?! 4L5C!�F\&�&)(�$2(/|U&7!9*�$2DU5G*�&7-�l���4�&);�&�465)|U&�F6&)&)(5�DC;�>7z�$'(�Du(+8�<IF\&�;:>7@�!N86#R4~!9*�86-/$2&7!:>7|U&);w*�4�&=165H!N*�@B&)z�rU&757;R! f ��8�323'$'(L5G;�$05 � ��4L5G*�&�;)hi)jCj � � � 57;R5G4�h � � � &)$23'3'rgh �'&�&7#^&);R5+h�i)jHj � ���A$'(+*�>H(>�   &�¢9(�>7z�!N�+$oh�i�j� )( � �A$'(+*�>H(�   465G32¨3'$O#^&UhAi�jCj+i�� � 5)|U>C;�&)3oh�i)j� � � �u#G��32>U!N�U&�r � � $'(6-+&)<n5G(?(�hAi�jCjY# � �s>n!�&);��©��&�4�;�<n57(�(�hi)jCjY# �6x�57*�*�&);R!9>C(�h   &)$O-+&)(/F6&);�D�h � �u#G��32&)3'305G(6-,h�i)j� Cj �   &)$O-/&�(/F6&);�D/� �u#G��32&)3'305G(6-,h�i)j� Cj �  &�¢9(�>7z�!N�+$t� � >g!N&)(+F6&);�D?h�i)j� � � �{>U>+-,hAi�j� n#UkRh�F�8�*p4�&);�&I*�4?&�@B>+#%8L!�z�$'3'3�F\&[>C(~*�4�>g!N&*�4657*.465)|U&=&)�+1�3'$0#%$'*�3'ru#^>C(6!9$O-/&);�&7-v*�4�&n;�&)3O57*�$'|U&I16&);N@B>H;�<n57(6#%&I>G@w32&7!N$2>C(�&}-{(�&)*9z�>H;��?!:>H(;�&)DH8�3O57;�5G(6-n&)��#^&)1�*�$2>C(=$2*�&)<q!%l

��������� * �+-,/.��1032������?A����������� ��

m�(w>H(�&�>G@?*�4�&�<=>g!N*�&��/*�&)(6!N$2|U&�(?&)*9z�>C;��/¨B3'&}!N$'>H(�$'(?D�!N*�86-/$2&7!%hHx�5G*�*�&);J!N>H(:&�*�5G3ol f i)j� Cj�k,&)�?5G<=¨$'(�&7-.*�4?&�&T&,&7#%*�>G@�3'&}!N$'>H(6! �I>G@�|H5G;�r/$2(�D�$2(/*�&)(6!9$'*9r.57(6-=1\>g!N$2*�$'>H(�$'(?D �.>H(n*�4�&   &)$O-/&�(/F6&);�D5G(6-�u#G��3'&)323O57(6- f i)j� Cj�k�<=>+-/&)3,>G@�;�&75C-/$2(�DI5G32>C86-,l

��4?&.DC>U573�>G@M*�4�&�!N*�86-/rsz�5C!�*�>q!N$'<I8�305G*�&.a�]+_0¥��UP%Zp§ � a^d'Z54HVOPRa^h z�4?>s#�5G(u;�&}5C-s;�&�DC8�305G;z�>C;J-�!.5G(L-�(�>H(/zM>C;R-?!�(�>H;�<n573'32rUh�F�8?*.*�&)(6-v*�>u>G|U&�;�;�&�DC8�305G;�$f!)&I&)��#^&)1�*�$2>C(vzM>C;J-�!���*�465G*$O!%hM*�4�&)ry1\&�;N@B>C;�< 5C!.$¤@w*�4�&)rv>H(�3'r~465H-�5C#�#%&7!�!.*�>EDC&�(�&);R573A1?;�>C(+8�(6#^$O5G*�$'>H(�;�8?3'&7!^l � >C;&)��57<=1�32&Uh�*�4?&=z�>H;R-76�8:9191;�<[$'DC4+*�F6&n1�;�>H(�>C8?(6#%&7-{*�>s;�4/r+<=&.z�$'*�47<=9191; F+ry!N86#R4~5165G*�$'&)(+*)l> � &7!9$'>C(?$'(�D ��z�5C!�>C16&);R57*�$2>C(6573'$"!�&7-tF+rI!N&)*�*�$'(?D.5:1?;�>C16>H;�*�$2>C(n>G@�zM&)$'DH4/*J!�*�>/!�&);�>?h>C;.F+r{;�&)<=>7|/$2(�Dn4�$O-?-/&)(v8�(?$'*R!:@B;�>C< *�4�&n(�&�*NzM>C;���l �£$2*�4 5s3'&}!N$'>H(�$'(?Ds;R57*�&n>G@�?+l@(s>H(4�$O-�-+&)({8?(�$'*J! f *�465G*.$0!%h�5�;R57(6-/>H<=3'rE#R4�>U!9&)(A()?CB >G@�4�$0-�-/&)(v8?(�$'*J!�zM&);�&[;�&)<=>7|U&7-6kRh6$'*z�5C!.@B>C8�(6-£*�4L5G*=*�4�&   &�$O-/&)(+F6&);�Dy5G(L- �u#G��32&)3'305G(6- f i)j� Hj�kI<=>+-/&�3A&)�+4�$2F�$'*�&7-~5{z�&757�-/$O!�!N>+#%$05G*�$2>C(vF6&)*9zM&)&)(E;�&)DH8�3O57;�57(6-{&)�?#%&)1?*�$'>H({zM>C;J-�!%¡�16&);9@B>C;�<n5G(6#^&tz�5C!�!9$'DH(�$��,#�5G(+*�3'rf F�8�*�(�>H*�#)5G*J5C!9*�;�>H1�4�$0#)5G323'r6k�zM>C;R!9&�>H(.&)��#^&)1�*�$2>C(6!^l���@L*�4�&�iD(A&)�?#%&)1?*�$'>H(wz�>C;J-�!�>H(.z�4�$O#R4*�4�&�<=>+-/&�3Cz�5H! *�&7!N*�&7-w5}@B*�&);�32&7!N$2>C(�$2(�D�h7#/EFB�z�&�;�&�$'(6#^>C;�;�&7#%*�3'r�1�;�>C(�>H8�(6#%&7-,hU5C!�#%>C<[165G;�&7-*�>u57(v&);�;�>C;w;J5G*�&I>G@�¢98L!N* � l � B >C(£iG(�;�&�DC8�305G;�zM>C;J-�! f *�4�&I1�;�&�¨�32&7!N$2>C(�$2(�Dn1\&�;N@B>C;�<n5G(L#%&z�5C!�&);�;�>C;�¨ @B;�&)&A@B>H;�573'3�*�&}!N*�z�>H;R-�!RkRl

� 8�;�*�4�&�;E5G*�*�&)<=1�*J!%hw$'(�*�4�& !�57<=&~!9*�86-/rgh�*�>�!N$2<t8�305G*�&v>C*�4�&);E5C!916&7#%*R!u>G@�!N8�;9@X5C#%&-/r�!93'&)�+$O5wz�&);�&w(�>C*�!N>I!986#)#%&7!�!�@B8�3X¡�*�4�&w32&7!N$2>C(�&7-=<=>+-+&)3�573O!N>I16&);N@B>H;�<=&}-t16>U>C;�32rn>C(s(?>C(�¨z�>C;J-�!%h,z�4�$O#R4szM>C8�30-s(�>C*�F6&p&)�/16&7#^*�&7-n$¤@�1�;�>C(+8�(6#%$05G*�$'>C(u;�8�3'&}!�zM&);�&p;�&)*J5G$'(?&7- f !N8�;9@X5C#%&

Page 62: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ���5� � � ��� ����� � � ��� � � � ����������� � ������� ����� � � � � � � j

-/r�!93'&)�+$O#�!�465)|U&�(�>H;�<n573�16&);9@B>C;�<q5G(6#%&�>C(s*�4�&7!9&CkRl �&)|U&);�*�4�&)32&7!�!^¡{5vzM&75G��-/$0!�!9>+#%$O57*�$'>H( z�5C!t@B>C8?(6-��Hl����?#%&)1�*�$'>H(£z�>C;J-�!=z�&);�&u<=>C;�&

5(&,&7#%*�&7-�F+r�-�5G<n57DC&p*�4657(u;�&)DH8�3O57;�z�>H;R-�!^l�x�57*�*�&�;R!N>H(u&)*�5G3ol f i�j� Hj�k�!N>H8�DC4+*�*�>[&)�/1?3O5G$2(*�4�$0!�;�&7!N8�32* f�� V'WOb?QU]UWA;�&}!N>C;�*�$2(�D{*�>~5E-/865G3�;�>H8�*�&Hk�F+r !N8�DHDC&7!9*�$'(?Dv*�4657*t;�&)DC8?3O5G;Iz�>H;R-�!z�>C8?3O-�573'z�5}r?!�F\&�<[>C;�&�;�&7!N$0!N*R57(/*�*�>�-�5G<n57DC&MF\&}#)5G86!9&�*�4�&)rp5G;�&�&T&,&7#%*�$2|U&)3'r�> >7|U&);�32&75G;�(�&7-l�F/r�*�4�&�(�&)*9z�>H;��,l<�£4�&)(w*�4�&�(�&�*NzM>C;���$O!�32&75G;�(�$'(�D�*�4?&�1?;�>C(+8�(6#^$O5G*�$'>H(:>7@6*�4?&�;�&)DC8?3O5G;�z�>H;R-��� � h/@B>C;�&)��57<=1�32&Uh/*�4�&�;�&)DC8�305G;�1?;�>C(+8�(6#^$O5G*�$'>H(s>G@ > ¨�$2(/*4��$O!�;�&)$2(/@B>C;J#%&7-=F/rn*�;R5G$2(�$'(?Dt>H(z�>C;J-�!�z�$2*�4 !N$2<=$'305G;[!N*�;�86#%*�8�;�&y5G(6-�1�;�>H(/8�(L#%$O57*�$'>H(�¡ ����������������� 8 �� �������� � l ��4�&&)��#^&)1�*�$2>C( z�>C;J-�� �� � h�4�>7z�&)|U&);�h�$O! >K>H(£$'*R!=>7z�(<�2¡{*�4?&{(�&�*NzM>C;���$O!I&)�/16>g!N&7-£*�>~*�4?$O!$';�;�&)DC8?3O5G;M1�;�>H(/8?(6#%$O57*�$2>C(n<t8L#c4I3'&7!�!�@B;�&��U8�&)(+*�32rI5G(6-�!N>.465H!�32&7!�!�>H1�16>C;�*�8�(�$2*9r=*�>I5H-G¢986!N*$'*R!�zM&)$'DH4/*J!�*�>=5H#)#%>C<[<=>+-�5G*�&�$'*�l�mo(+*�&);�&7!N*�$'(�DH3'rUh+x�57*�*�&�;R!N>H(s&)*�573olf�K! f i)j� Cj�k�&)�/1?3O5G(L5G*�$2>C($O!�&��U8�$'|H573'&)(+*�*�>{$2(/*�&);�1�;�&)*�$2(�Ds*�4�&�-/$O!�!N>+#%$05G*�$'>C(�5C!I5�_RZ�a�QU]+_�P%Z[�U_cWXV ¥��UP%W f 5C!I-/$O!�#%86!�!N&7-5GF6>7|U& �   4L5G3'32$O#%&gh�i�j� � �kRl���4657*�$O!^h�-�57<n5GDH&t4L5C!�5\&,&7#%*�&}-�F6>C*�4~;�&)DH8�3O57;�57(6-{&)�?#%&)1?*�$'>H(z�>C;J-�!%h�F�8?*=*�4�&�&T&,&7#%*I$O!t<[>C;�&n1�;�>C(�>H8�(6#%&}-�>C(£&)�?#%&)1�*�$'>H(�z�>H;R-�!IF\&}#)5G86!9&u*�4�&�r�57;�&>K4657;R-/&);4�/*�>t1�;�>C(�>H8�(6#%& f >H;�;R5G*�4�&);�h�(�>C*�5C!�z�&)323�32&75G;�(�&7-\kJl

�¦!9$'<=$23O5G;M&T&,&7#%*�z�5H!�@B>H8�(6-sF+rn��8�3'32$'(657;�$05 f i�jCj/E/kRl �A&w3'&7!9$'>H(�&7-n5t|H5G;�$O5G*�$'>H(s>G@�*�4�& �����*R5G32�{(?&)*9z�>C;��v$'(ª!N$'�ª-/$ &,&);�&)(/*pz�5)r?!%hM5G(6-{@B>C8?(6-�*�465G*�h�@B>H; �6|U&=>G@�*�4�&=32&7!N$2>C(�$2(�D<=&)*�4?>+-�!%h�>H(�3'r &)�?#%&)1�*�$'>C( z�>H;R-�!tzM&);�&�3'>g!N*=*�4�;�>H8�DC4 -�5G<q5GDC&gl��4�&E!9$'�+*�4�32&7!N$2>C(�$2(�D<=&)*�4?>+-t465C-n(�>[-/$ &,&);�&)(/*�$O573�&T&,&7#%*�l

��4?&u;�&7!98�3'*J!t>G@�x�57*�*�&�;R!N>H( &�*=573ol f i)j� Hj�k[5G(L- ��8�323'$2(65G;�$O5 f i�jCj/E/kn-+>v(�>C*n1�;�>7|/$0-/&!N*�;�>C(�DE&)|+$O-/&�(6#%&t@B>H;I5G(�$2(/*�&);�(L5G3�-+865G3�;�>C8�*�&�@B>C;.4L5G(6-/32$'(�DE;�&�DC8�305G;R!.57(6-�&���#%&�1�*�$2>C(6!^l� $'�U&[5G3'3�!N$2(�DC32&n-/$O!�!N>+#%$05G*�$'>C(L!%h�*�4�&)$2;R!IPR�UTsF6&�&��/1�305G$2(�&7-E5}z�5)rv5H!.5�;�&}!N>C8?;R#%&�5G;�*�$e@X5C#%*�h5G3'*�4�>C8?DC4*�4�$O!t&��/1�305G(657*�$2>C(�;�&)<n57$'(6!I#%>H(C¢9&7#%*�8�;�&Ul � ;�&7!98�3'*=*�465G*�-/&�<=>C(6!9*�;J5G*�&}-�*�4�&>C1�16>U!9$'*�&�-+$O!�!9>+#%$O57*�$2>C(=zM>C8�30-�h/$2(=*R57(6-/&)< z�$'*�4=*�4�$0!�;�&7!N8�32*)hUF6&w<t86#R4.<=>H;�&�#%>H(/|+$'(6#^$'(�D?l

��������� � �}! " .��\�9� +$#{� �+�, . �1032���������������,���

� #%>H(�(�&7#^*�$'>H(�$O!9*=3'&}!N$'>H(�$'(?D�&��/16&);�$'<=&)(+*I!N$2<=$'305G;=*�>~*�4�>g!N&~-/&}!�#%;�$'F6&7-�5GF6>7|U&{z�5C!=8�(�¨-/&);�*J5G�U&)(£F+r �u5G;J#c4�<q5G( f i)jHjn#�kJl   4?&E5G3O!9>~*�;R57$'(�&}-£5�#^>C(�(�&}#%*�$2>C(�$0!N*=(�&�*NzM>C;���>C( 5

%'&<[ G�unGIg dfJ�gjq VXWnbPG$JXd�Z\GI`'L\GIW)(nGIgHs%VXWYL�* b,+l]_G�]_]'V^WYL�- E�MPOAQTR�Q�UCW7GID klJ�gjm%B7WYL\GIge]aGIEH`aJ�W `_W st`aE�V�biDHBYV^]_]/.qpJ�gjG�gHG�q1`aW7`aEcbPG�W4DeJXd102&3.\unG54�46-7EjB7g d V�bPGhL).\EH]aG877`'bPE'9�VFklGAVXmTGIg<d"J�gHq JXd�EjB7g d VTbPGtL).\Ej]_G�7(`'VFk<[7G�gHGhVFEHq V^]a]unJ�gjDH`aJ�WpJXd�gHG�s�B7]'VXg<klJ�gPL\E�VXgjG$q1`aEHu7gjJ�W7JTB7WYbPGoL1VXE<klGI]a] M @CGI[7gjq V^W7W": @CB�(;9 OoQ�QTS�UIv

Page 63: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

E ? ������������� ����������������� ��� ����� � ����������� � ������� �"!���# � � !������

��865H!N$2;�&)DH8�3O57;�*J5C!9��hU3'&}!N$'>H(�&7-�*�4�&A4?$O-�-/&�(.8�(�$'*J!%h+5G(L-=#%>C<[165G;�&7-�16&);N@B>H;�<n57(6#%&�>H(=;�&�DC8�305G;5G(6-s&)�?#%&)1?*�$'>H(nz�>C;J-�!%l�mo(u#%>H(/*�;R5C!9*�*�>qx�5G*�*�&);J!N>C(u&�*�573ol"� ! f i�j� CjUk�z�>C;J-/¨B;�&75H-/$'(�Dq!N*�8L-/rUh-/&7!�#^;�$'F6&7-~57F\>7|U&Uh�u5G;R#R4�<n57(<�K!w*R5H!N�~z�5H! f 5G(£57(65G32>CDHr�*�>+k�*�4�&s<q5G1�1�$2(�Du>G@ ��(?DC3'$0!N4|U&);�F6!�*�>t*�4�&)$2;�165C!9*�*�&)(L!N&�@B>C;�<n!%l � 8�;�*�4�&);�<[>C;�&gh�!N4?&�3'&}!N$'>H(�&7-=*�4?&�(�&)*9zM>C;����%Z'¥�QU_cZM5G(L-§U]/_^VOTCS�*�;J5G$'(?$'(�D?h65G(6-n(�>C*�5}@B*�&);�z�5G;R-?!%h65C!�$'(�x�57*�*�&);R!9>C(s&�*�5G3ol f i�j� CjUkRl

� @B&)&7-U@B>C;�z�5G;J-s(�&)*9z�>H;��uz�5H!�*�;R57$'(�&}-�>H({*�4�&t1L5C!N*�¨�*�&)(6!9&t*J5C!N�u@B>C; #���&)16>+#R46!%l � &)¨!N$'>H(�$'(?D=z�5H!A>C16&);J5G*�$2>C(6573'$f!)&7-sF+r�<q5G�+$'(�DI5t1?;�>C16>H;�*�$2>C(E>G@ f ;J5G(6-+>C<=32rs#R4�>g!N&)(�kM4�$0-�-/&)(8�(�$'*J!�$'(�>H16&);R57*�$'|U&gl �u5G;R#R4�<n57(=;�&}#%>C;J-/&7-t*�4�&w&T&,&7#%*R!�>7@�3'&}!N$'>H(�$'(?D�#CB[h�iCi B[h�#n# B=h ��� B5G(6- E EFB >G@�4�$0-�-/&)(n8�(?$'*R!��)l

�u57;R#R4�<n57( f i�jCjY#�k�#%>C<[165G;�&7-:*�4�&�16&);N@B>H;�<n57(6#%&�>7@,*�4�&�32&7!N$2>C(�&7-w(�&)*9z�>H;��w>C(I;�&�DC8�305G;5G(6-~&)��#^&)1�*�$2>C(~|U&);�F6!.5G*I*�4�&�&)(6-~>G@w*�;R5G$2(�$'(?D�l£mo(£#^>C(+*�;R5H!N*I*�>E*�4�&�x�5G*�*�&);J!N>H(�&)*I573olf i)j� CjUk�;�&7!98�3'*J!%h+!N4�&�@B>C8�(6-I*�4657*w_cZBSg]�de�U_�1657*�*�&�;�(6!�z�&);�&A<=>H;�&�!9&)(6!N$2*�$2|U&�*�>.-?5G<n57DC&�*�4657(&)��#^&)1�*�$2>C(6!^l � >H;�&)�?5G<=1?3'&Uh�5s(?&)*9z�>C;��uz�$'*�47E E B >7@�$2*R!:4?$O-�-/&�({8�(?$'*R!w;�&)<[>G|U&}-s1�;�$2>C;*�>I*�;R57$'(�$2(�DI<n5C-/&�&);�;�>C;R!�>C( � � B">7@�;�&�DC8�305G;�|U&);�F6!^h�z�4�$'32&�3'&}!�!�*�4657(viD? B >G@�&)�?#%&)1?*�$'>H(|U&);�F6!.z�&�;�&u$'(L#%>C;�;�&7#%*�3'rv$2( �6&7#^*�&7-�l �&)*9z�>C;���!.3'&}!N$'>H(�&7-£-/8?;�$'(?Dv*�;J5G$'(?$'(�D -/$0!N1�305}rU&}-�5!N$'<[$'3O57;�1657*�*�&);�(�¡ # � B >G@M;�&)DC8�305G;�|U&�;�F6!�z�&);�& >K3'>g!N*4�\|U&);J!N86!�3'&7!�!�*�465G( � B >G@M&)�?#%&)1?*�$'>H(|U&);�F6! f FL5C!N&�3'$'(?&�16&);N@B>H;�<n57(6#%&�>G@,8�(?3'&7!9$'>C(?&7-:(�&�*NzM>C;���!�5G*�*�4�&�&�(6-�>G@6*�;R57$'(�$2(�D�z�5H!�iD?)?CB#%>C;�;�&7#%*^kRl

��4?&�-/$0!�!N>+#^$O5G*�$'>H(�z�5H! (?>C*�|U&);�r�!N*�;�>C(?D�hCF�8?*�$2*�$O!�#%3'&757; f 57(6-�!9*R5G*�$O!9*�$O#�5G3'32r�!9$'DH(�$��,#�5G(+*%k*�4657*)h�$'(�#%>H(/*�;R5H!N*�*�>Ix�57*�*�&�;R!N>H(s&)*�573olf�K! f i�j� Hj�k �6(L-/$'(�Dg!%h�;�&)DC8�305G;�1657*�*�&);�(6!�!N8 &�&�;�&7-=@X5G;<=>C;�&A@B;�>H< -�5G<q5GDC&w*�465G(�&)��#^&)1�*�$2>C(6!^l

�u57;R#R4�<n57(<�K!A>H(�&)¨Bz�5)rE-/$0!�!N>+#^$O5G*�$'>H(~#)5G(ª5G3O!9>sF6&I&)�/1?3O5G$2(�&7-sF+rE5s!9$'<=$23O5G;�;�&}!N>C8?;R#%&5G;�*�$¤@X5H#%*)l�mo(=*�4�&�*�;J5G$2(�$'(�DI!9&)*�86!9&7-�h/;�&)DC8?3O5G;�1L5G*�*�&);�(L!�>C8�*�(/8�<IF6&);�&}-�&)�?#%&)1?*�$'>H(6!�F+r�E ���*�> ( � l ����#^&)1�*�$2>C(~1657*�*�&�;�(6!.z�&);�&Uh�4�>7z�&)|U&);�h�1�;�&}!N&)(+*�&7- �.QU_cZnQN¥^W9Z^Tu1\&�;t&)16>+#R4~*�4657(;�&)DH8�3O57;�1L5G*�*�&);�(L!%h/$2(�@X5H#%*�8?1t*�>=i �w*�$2<=&7!�<=>H;�&�>7@B*�&)( f *�>.#)571�*�8�;�&�*�4?&�#R465G;J5C#%*�&);�$0!N*�$O#�>G@��(?DC3'$0!N4uz�4�&�;�&)F+r���$';�;�&)DH8�3O57;�|U&);�F6!A#^>C<=1�;�$O!9&.5t305G;�DH&.16>C;�*�$'>H({>7@�*�4�&.<=>g!N*�#%>C<=<[>C(�32r86!N&7-n|U&);�FL!��.1�l UkRl�$'|U&)(n*�4?&7!N&p<t8�32*�$21�3'&�1�;�&}!N&)(+*R57*�$'>H(6!%h6*�4?&);�&pz�&);�& �.QU_cZ�&)�?#%&)1?*�$'>H(165G*�*�&);�(6! f E )?�k[1�;�&7!9&)(+*�&7-£16&);n&)16>+#c4�*�4657(;�&�DC8�305G;n165G*�*�&);�(6! f E ��� kJl mo(£*�4�$0!q32$'DH4/*�h

�'&<[ G�G�7 VTbPD<WYV^DHB7gjG JXd DH[7GIEjGt]aGIEj`aJ�W7El`aE<W7J�D<q%V�L\G$bP]aGAVXg<`aW *:VXgcbj[7q%VXW:McOAQTQ�STU��\J�Wpu v� F`aD�`aE<EjDcVXDjGALDj[YVXD���&<[7Gh]aGIEj`_JTW7EFgcVXWnL\J�qp] .%GI]a`aq1`aWYV^DHGAL:bPJ�W7W GAbPDH`aJTW7E (nGID klGIGIW�DH[ G1`aW7u7B7DFVXWYL/[7`'L7L(GIWK]'V .�GIg J^d Dj[7GW GID k�JTgHm�� 9\k<[ `_]aG$J�Wpu v�QF`aD�`aE<EjDcVXDjGAL%Dj[YVXD<Dj[7G���������������� �"!$#�Dj[7GIqpEHGI]"%�G�E<k�GIgjG ]aGIEH`aJTW7GAL�v

Page 64: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ���5� � � ��� ����� � � ��� � � � ����������� � ������� ����� � � � � � E�i

*�4�&n;�&�3O5G*�$'|U&=;�&7!N$23'$2&)(6#%&=>7@w&)�?#%&)1�*�$'>H(�1L5G*�*�&);�(L!�*�>v-�57<n5GDH&n$O!.(�>C*I*�4657*n!N8?;�1�;�$O!N$2(�DE>C;!N$'DH(�$��\#)5G(+*)l

��>GzM&)|U&);�h/*R57�U&)(n*�>HDC&)*�4�&);�z�$2*�4�x�5G*�*�&);J!N>H(u&)*�573olf�K! f i�j� Hj�k�57(6-u��8�3'32$'(657;�$05 �K! f i�jCj E+k;�&7!98�3'*J!%ht�u5G;R#R4�<n57(<�K! f i�jCjn#Uk.;�&�|U&);R!9&n-/$O!�!N>+#%$05G*�$'>C( &7!N*J5GF�32$O!94�&7!.5 §UQU]/�%d2Z�§UV¤aRa�QGP�VO�CWoVOQUTF\&�*NzM&)&)(�;�&)DH8�3O57;w5G(6-u&)�?#%&)1�*�$'>H(s1657*�*�&�;�(6!�$'(�#%>C(?(�&7#%*�$'>C(?$O!N*�(�&)*9z�>H;��?!%lw��4�$0!�&�|/$0-/&)(6#%&$O! ��86573'$2*R5G*�$'|U&)32r{*�4�&{a����tZp&)|+$O-/&)(L#%&=*�4L5G*=$0!�86!9&7-�*�>~!N8?1�16>C;�*[*�4�&�(�>C*�$'>C(£>7@p5v-/8L5G3;�>C8?*�&I$'(E4/8�<q5G(E1�;�>+#%&}!�!N$2(�D f x�$'(��U&);�h�i)jHj/i7kRl �$'|U&�(u*�4�&[#%>C;�&=5H!�!98�<=1�*�$'>C(E*�4L5G*.-+>C8�¨F�3'&[-/$O!�!N>+#%$05G*�$'>C(L!�#)57({>H(�3'ry5G;�$O!N&I$'(E<=>+-/8?3O5G;p!9r�!9*�&)<n! fN  46573'32$O#%&Uh�i�j� � +h�1�l # E �kJh�>C(�&<t86!9*�*�4�&);�&^@B>C;�&p#%>H(6#%3286-/&w*�4657*�#^>C(�(�&}#%*�$2>C(�$0!N*�(�&)*9zM>C;��?!�5G;�&Uh6F/r=*�4�&p!�57<=&p!N*R57(6-�57;R-s>G@&)|/$0-/&)(6#^&Uh+5C!�<=>+-/8�305G;�5H!�4+8�<n57(n1�;�>+#%&}!�!N$2(�D[!Nr?!N*�&�<n!%l

��(�&Mz�&757�/(?&7!�!�$2(�*�4?$O!�&)|+$O-/&�(6#%&�$0! *�465G*�*�4�&�-/>C8?F�3'&M-/$0!�!N>+#^$O5G*�$'>H(I#%>C(6!9$O!9*R!�>G@6>H(�&)¨Bz�5)r-/$O!�!N>+#%$05G*�$2>C(6!�*�4657*�z�&);�&A;�&7#%>H;R-/&7-.>C(�a7Zo`?�U_��CW9Z�(�&�*NzM>C;���!���5G(L-t&75C#R4[!N$'(?DC3'&�-/$0!�!N>+#^$O5G*�$'>H(#)5G(I573'z�5)r?!�F6&A&��/1�305G$2(�&7-�5H!�5A;�&7!9>C8�;J#%&�5G;�*�$e@X5C#%* f 5C!�&)�+1�3O57$'(�&}-�5GF6>7|U&CkJl A>C*�&UhC4�>7z�&�|U&);)h*�4657*�*�4�&.a����tZ�z�&757�/(?&7!�!�&)�+$O!9*R!�$'(n4/8?<n5G(n-+$O!�!9>+#%$O57*�$2>C(n&)|+$O-/&)(L#%& �U$'*�#%>C(6!9$O!9*R!�!N>C32&)3'rI>G@>C(�&)¨Bz�5)rn-+$O!�!9>+#%$O57*�$2>C(6!�@B>C8�(L-�$'(�!9&)165G;J5G*�&�$'(L-/$'|+$O-/8L5G3O!^l

� <t8L#c4~<=>H;�&n16>GzM&);N@B8?3�;�&7!98�3'*�h�z�4�$0#c4 z�>C8?3O- Z54HP%ZRZ�§s*�4�&u-/$0!�!9>+#%$O57*�$'>H( &�|/$0-/&)(6#%&@B>C8�(6-w$'(w4+8�<n5G(L!%h)z�>H8�3O-wF6&�5�*9z�>H¨�z�5}r�-/$O!�!N>+#%$05G*�$2>C(w@B>C8�(6-w>C(p*�4�&�QUT\Z,(�&)*9z�>H;���*�;R5G$2(�&7->C(s*�4�&[QUT\Z�*J5C!9��l   8L#c4�5.;�&7!98�3'*M$O!�-/$0!�#%86!�!N&7-n(�&)�+*)l

��������� � 2:��� �� + 2�������������������

m�(L!N*�&}5C-=>G@�<=>+-/&)323'$2(�D.5 �U865C!9$';�&)DC8�305G;�*J5C!N�n*�465G*�$0!�5C#%*�865G323'rI3'&757;�(�&7-=F+rt4+8�<n57(6! f 5H!�$'(*�4�&p!N*�86-/$2&7!A-+&7!�#%;�$'F6&7-n5GF6>7|U&CkJh6��8�3'32$'(657;�$O5.57(6-���4L5G*�&�; f i)jCj � k�-+&)|/$0!N&7-n5.(�>7|U&)3�&)�?#%&)1�¨*�$'>H(=*R5H!N�Iz�$'*�4 #n#/E >K;�&�DC8�305G;\�U1657*�*�&);�(6!M5G(6- � # >K&)�?#%&)1�*�$'>H(<�C1657*�*�&�;�(6!�@B>C;�*�4�&)$2;�32&7!N$2>C(�$2(�D!N*�8L-/$'&7! � l ��8�3'32$'(657;�$05s5G(L- ��4657*�&);4�K! f i�jCj � k.*�;R5G$2(�$'(?DE5G(6-~3'&7!9$'>C(?$'(�Du1�;�>+#%&7-/8?;�&7!.z�&);�&<t86#R4.<=>H;�&�&)�+*�&�(6!N$2|U&�*�4657(s$'([*�4�&�*9zM>I!N*�8L-/$'&7!M-/&7!�#%;�$2F\&}-=5GF6>7|U&Ul���>C*�4�5:@B&)&7-�@B>H;�z�57;R-(�&)*9z�>H;��p5G(6-I5�#)5H!�#)5H-/&�#%>H;�;�&�3O5G*�$'>H(.(�&)*9z�>H;�� fo� 5G4?3'<n57(K� � &)F�$'&�;�&Uh+i)jHj ?�k�z�&);�&�*�;R5G$2(�&7->C(=*�4�$O!�<n5G1�1?$'(�Dw*R5H!N�,h�57(6-=|C57;�$2>C86!�*9r+1\&}!�>7@�3'&7!9$'>H(6!�zM&);�&�5G1�1?3'$'&}- f $2(s!9&)1657;R5G*�&w*�;�$05G30!ck*�>~*�4�&E(�&)*9zM>C;��?!%l � &7!N$2>C(�$2(�D~*�&7#R4�(�$ ��8?&7!t$'(L#%3'86-+&7-£#%>C;�;�8�1?*�$'(?D�zM&)$'DH4/*J!tz�$'*�4 (?>C$O!9&Uh

�6&<[ G�L\GIDPVX`a]aE�J^d DH[7G @CB7]a]a`_WnVXgH`'V$VXWnL +l[YV^DHGIg$MPOAQ�Q���U Ej`aqhB7]'VXDH`aJTWV^gHG�W J�DlgHG��TB7`agHGoL�9YV^D�Dj[7`aE�unJ�`aW\D'9TDHJB WYL\GIgjEHDcV^WYL%Dj[7G ]aGIEH`aJTW7`aW7stgjGIEHB ]_DjEAv &<[7G EH`aqhB7]'V^DH`aJ�WFk<`a]_]�(nG L\`aEcbPB EHEHGoL `aW1qpJ�gjG L(GIDcV^`_]�`aW%DH[ G +l[nVXu7DjGIg� 9\k<[7GIgjGtVFgHGIu ]_`'bIV^DH`aJ�Wp`aE�L\GIEcbigH`/(YGoL�v

Page 65: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

E�# ������������� ����������������� ��� ����� � ����������� � ������� �"!���# � � !������

dissociationMarchman (1992)

Bullinaria & Chater (1993)

7.5%

41.5%

96.9%

< 5%

< 10%

23.8%

regular patterns exception patterns

Post-lesioning errors

on

35.0%

27.0%

0.0%

0.0%

dissociation

double dissociation

Patterson et al. (1989)

� $'DC8?;�&�E?l'iC¡M�¦!N8�<[<n5G;�r.>G@�-/$O!�!N>+#%$05G*�$2>C(6!�@B>C8?(6-�$2(�32&7!N$2>C(�&}-=#%>C(?(�&7#%*�$'>C(?$O!N*�(?&)*9z�>C;���!^l

;�&7!�#)5G32$'(�Dw*�4?&)< f DH3'>CFL5G3'32r.>C;�;R57(6-/>H<=3'r6kRhU>C;M#%>H<=1�32&)*�&)32rw;�&)<=>7|+$'(�D�*�4?&)<ul��A3O!9>�hU4�$0-�-/&)(8�(�$'*J!�z�&);�&w;�&)<=>7|U&7-:@B;�>C< *�4�&w(�&)*9z�>H;��,l

��@B*�&);�DH3'>CFL5G3�;�&7!�#)5G32$'(�D.>7@�*�4�&pz�&)$2DC4+*R!�z�5C!A16&);9@B>C;�<[&7- f 573'3�zM&)$'DH4/*J!A57;�&w<t8?3'*�$21�3'$2&7-F/rE5�!N<n573'3�@X5H#%*�>H; ��*�4?$O!�3'&7!9$'>H(�$'(�Dn*�&7#c4?(�$ �U8�&.$O!�<=&}5G(+*�*�>�<=>+-/&)3�5n(�&)8�;�>C*�;R5G(L!N<=$2*�*�&�;$'<IF65G305G(6#%&HkRh75�>C(�&�¨�z�5}r�-/$O!�!N>+#%$05G*�$'>C(Iz�5H!�@B>C8�(6-,¡�j (+lKj B¦>G@�5G323�&)�?#%&)1�*�$'>C(p165G*�*�&);�(6!�z�&);�&$'(6#%>H;�;�&7#%*�32rw<n5G1�16&7-,hCz�4�$'32&wT�Q�;�&)DH8�3O57;�165G*�*�&);�(6!�z�&);�&�5(&,&7#^*�&7-�l��¦_RZ^YGZ^_�a7Z�-/$0!�!N>+#^$O5G*�$'>H(>G@�3'&}!�!N&�;:<q5GDC(?$'*�8L-/&tz�5C!p5G3O!9>u;�&7#^>C;R-+&7-�¡wF/rE;�&)<[>G|+$'(?Dn5s!9$'(�DH3'&Iz�&)$2DC4+*:F6&)*9zM&)&)(E*�4�&$'(�1�8?*�305)rU&);n5G(L- *�4�&u4?$O-�-/&�( 305}rU&�;)h E?iCl �CB >G@I;�&)DC8?3O5G;n1657*�*�&);�(6!nz�&);�&7>K32>U!N*4��F+r£*�4�&(�&)*9z�>H;��,h�z�4�$'32&n&)��#^&)1�*�$2>C( 165G*�*�&);�(6!tz�&�;�&�!N*�$'3'3�<n571�16&7-v1\&�;N@B&7#%*�3'rUl���4�$0!�;�&7!N8?3'*Iz�5C!&7!�!9&)(/*�$O573'3'r.;�&)1�32$O#)57*�&7-t$2(n*�4�&p#)5H!�#)5H-/&.#%>H;�;�&)3O57*�$'>H(n(�&)*9z�>H;��[5C!�z�&)323ol

��8?3'3'$2(65G;�$O5�57(6-s��465G*�&); f i)jHj � k�4?&)(6#%&�!N86#�#%&)&7-/&}-�$'(=&)32$O#%$2*�$2(�D�5[§UQU]/�^d'Zp§UV¤aRa�Q7P)VO�CWoVOQUT+hF\&�*NzM&)&)(u&)�?#%&)1?*�$'>H(v57(6-{;�&)DC8�305G;w1657*�*�&�;�(6!^h�$'(y5s#%>H(�(�&7#%*�$'>H(�$O!9*�(�&)*9z�>H;��u*�;R5G$2(�&7-{>H(~5��865H!N$2;�&)DH8�3O57;t<n571�1�$2(�Du*R5H!N�,l£� !N8�<=<q5G;�rE>G@�*�4�&�-/$O!�!N>+#%$05G*�$2>C(6!I-/$0!�#%86!�!N&7- !N>u@X5G;I$'(#%>C(�(?&7#%*�$2>C(�$0!N*M(�&)*9z�>H;��?!�$O!�-/&)1?$O#%*�&7-t$'( � $2DC8�;�& E�l'iHl

��>Gz�!9$'DC(?$��,#)57(/*w$0!A*�4�&[��8�323'$'(L5G;�$05t57(6-v��465G*�&); f i)jHj � kw-/>H8�F�3'&[-/$0!�!N>+#^$O5G*�$'>H(�h�#%>C<=¨165G;�&7-{z�$'*�4~*�4�>g!N&=;�&7#%>C;J-/&7-{>H(~4/8�<q5G(y!N8�F�¢9&7#^*R! $ ��4�& �.�)SUT�V'WX]+§/Z:>7@�*�4�&=(�&�*NzM>C;��l� !-/$O!�!N>+#%$05G*�$2>C(6!I$O!.DC;�&}5G*�&�;t*�465G( *�4�>g!N&u*9r/1?$O#)573'3'rE;�&�1\>H;�*�&7-�$2(�*�4?&u#%>HDC(�$2*�$'|U&[(�&)8�;�>C16!9r/¨#c4�>H3'>HDC$O#�5G3�32$'*�&);R57*�8�;�&U¡�@B>C;.&)�?5G<=1?3'&Uh�$'(ª5s;�&)|+$'&)z�>7@ �6|U&=1657*�$2&)(/*J!�&)�+4�$'F�$2*�$2(�D�!N8�;9@X5C#%&-/r�!93'&)�+$O5+h   46573'32$O#%& f i)j� � �k�@B>C8�(6-E*�4657*�(�>H(�&t4L5C-{&);�;�>H;:;J5G*�&7!�>C(v&)�?#%&)1?*�$'>H(uz�>H;R-�!�&)�+¨#%&)&7-/$2(�D �HjCB[h�#^>C<=1657;�&7-Iz�$'*�4���8�323'$2(65G;�$O5�57(6-���4L5G*�&�;\�K!�(?&)*9z�>C;��=&);�;�>C;�;J5G*�&:>7@Mj (+lKj B=l

��>H<=1657;�$'(?D�*�4�&u<n57DC(�$2*�86-/&u>7@.*�4�&E-/$O!�!N>+#%$05G*�$'>C(L!�$O!I1�;�>HF�3'&)<q5G*�$0#Ch�F6&7#)5786!N&E*�4?&)rz�&);�&�;�&7#%>H;R-/&}-:@B>C;�*J5C!9��!�>G@�|H5C!N*�3'rI-/$'&,&);�$2(�Dp#%>C<=1?3'&)�+$'*9rHl��A>7z�&)|U&�;)h7*�4�&�<=>+-/&)3c�K!�-/>C8?F�3'&

Page 66: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � �'����� ��� � !���#1� � �D��� ���5� � � ��� ����� � � � E �

-/$O!�!N>+#%$05G*�$2>C(I$O!�*�4�&)>H;�&)*�$O#)573'3'r�$'<=16>C;�*R57(/*�@B>H;�>C*�4�&);�;�&}5C!N>H(6!%l�mo(.*�4�&�#%>CDH(�$'*�$'|U&M(�&)8�;�>C16!9r/¨#c4�>H3'>HDC$O#�5G3+3'$'*�&);R57*�8�;�&Uh75G323�-+>C8�F�32&�-/$0!�!9>+#%$O57*�$'>H(6!�57;�&�;�&}#%>C;J-/&7-:>7|U&);�57*�3'&}5C!N*MW � Q�165G*�$'&)(+*R!^h&75C#R4nz�$'*�4�5=!N$2(�DC32&w>C(�&)¨Bz�5)r�-/$0!�!N>+#^$O5G*�$'>H(�l���4�$O!�;�&7!9*�;�$O#%*�$'>C(�$O!�>H8�*�>G@�(�&7#%&7!�!N$2*Nr,¡�*�4�&);�&$O!�(�&)|U&);�32$'�U&)32r:*�>.F6&w5�#)5H!N&�>7@�5�!9$'(�DH3'&�165G*�$'&)(+*�!98 &,&);�$2(�D.5w3'&7!9$'>C( f z�$2*�4=*�4�&w57*�*�&�(6-�5G(+*-/$O!�!N>+#%$05G*�$2>C(�kJh�#%>C<=1?3'&)*�&)3'r=;�&7#%>7|U&);�$'(�D?h�5G(6-u*�4?&)(v!98 &,&);�$2(�Dn(�>7|U&)3�-�57<n5GDH&.*�4657*�&)32$O#%$2*R!*�4�&w>C1?1\>g!N$2*�&.-+$O!�!9>+#%$O57*�$2>C(�l

��4?&t1�;�>CF�32&)< z�$2*�4y-/>C8?F�3'&[-/$O!�!N>+#%$05G*�$'>C(L!:;�&}#%>C;J-/&7-s>7|U&);�*9z�>n1657*�$2&)(/*J!�$O!�*�4657*w*�4�&-/$ &,&);�&)(6#%&7!�$2(u16&);N@B>H;�<n57(6#%&wF6&)*9z�&)&)(�*�4�&p*9z�>I165G*�$'&)(+*R!�<n5)r=F6&Uh�*�>n!N>H<=&p-/&)DC;�&)&Uh,-/8�&*�>�VOT�§UVOY)VO§U]+�Cd�§UV �wZ^_cZ^T?P%Z�a fN  465G323'$O#^&Uh�i�j� � UkRl � >H;A&)�?5G<[1�3'&UhH*�4�&p165G*�$'&)(+*R!�<n5)rI465)|U&�465H-8�(�&��U865G3�5GF�$23'$'*9rn>C(E;�&�DC8�305G;p5G(6-u&)�?#%&)1�*�$'>H(uz�>C;J-�!�F6&%@B>C;�&.*�4�&I3'&7!9$'>H(�$'(�D[>+#)#%8�;�;�&7-���>H;)h>C(�&p>C;�F6>C*�4u>G@�*�4�&�1L5G*�$2&)(+*R!�<n5)r=F6&�8L!N$'(?Dn5t#^>C<=16&)(6!�5G*�>C;�r�!9*�;R57*�&)DHrn*�>=<n5H!N�=4?$O!�>C;4�&);�-/&��\#%$'*M>C(s>H(�&p#%3O5H!�!�>G@�z�>H;R-�!^l

��4?&u-/>H8�F�3'&�-/$O!�!N>+#%$05G*�$'>C(�@B>H8�(6-~>C(£*�4?&u��8�323'$'(L5G;�$05u5G(6-£��465G*�&); f i)jCj � kI(�&)*9zM>C;��$O!t*�4�&)>C;�&)*�$0#)5G323'r~<=>H;�& > 1�8�;�&�� f $ol�&Ul'h�<[>C;�&�!N*�;R5G$2DC4+*N@B>H;�z�57;R- *�>v$'(+*�&�;�1�;�&)*%kJh�F6&7#�5G86!9&u$'*$O!.#%&);�*R57$'(v*�465G*.$2*I#)5G(�(?>C*.F6&u5H!�#%;�$'F6&7-v*�>u$2(6-/$'|+$O-+865G3�-/$ &,&);�&)(6#%&7!^¡.*�4�&�!�57<=&=*�;R5G$2(�&7-(�&)*9z�>H;��vz�5C!.3'&7!9$'>C(?&7-{$'(~F6>C*�4�#)5C!9&7!%hM5G(L-�(�>y#%>C<[1\&�(6!�57*�>C;�r~!N*�;R57*�&)DH$'&7!.#%>H8�3O-~465)|U&F\&�&)(�-/&)|U&)32>C16&7-�h+F\&}#)5G86!9&w(�>t;�&)3'&}5G;�(?$'(�D.z�5C!�16&);�<[$'*�*�&7-=5)@B*�&);�32&7!N$2>C(�$2(�D�l

��8�&A*�>w*�4�&�&75C!9&A>7@�<n57(�$'1?8�3O57*�$'>H(.>G@ #%>C(�(?&7#%*�$2>C(�$0!N*�<=>+-/&�3O!%hH��8�323'$'(L5G;�$05�5G(L-���465G*�&);f i)jHj � k.z�&);�&u57F�3'&n*�> �6(6-�5u*�4?&)>C;�&)*�$0#)5G323'rv<=>H;�&=16>7z�&�;N@B8�3�-/>C8?F�3'&�-/$O!�!N>+#%$05G*�$2>C( *�4657(z�$'3'3�3'$2�U&)3'r[&)|U&);�F6&�@B>C8?(6-�$2({4+8�<n57(u!98�F�¢9&7#%*J!���>C(�&[#%>H8�3O-u57;�DC8?&t*�465G*w*�4?&I5G1�1657;�&)(+*�32r$'(�&7!�#)5G1L5GF�32&Uh�57(6-s#%>H(/*�;�>7|U&);J!N$O573oh+#%>H(6#%3'8L!N$'>H(n$O!�*�4L5G*�*�4�&);�&w$O! �U865G32$'*R57*�$2|U&)3'rI!9$'<=$23O5G;�&)|+$'¨-/&)(6#%&�@B>H;�5G(�$2(/*�&);�(L5G3+-/86573U;�>H8�*�&M$'(p#%>C(?(�&7#%*�$'>C(?$O!N*�(?&)*9z�>C;���!�57(6-:$2(w4/8�<q5G(6!^h75G*�3'&75H!N*�5C!@X5G;�5C!�&�|/$0-/&)(6#%&�F65C!9&7-=>C(�-/$O!�!N>+#%$05G*�$'>C(L!�$0!�#%>H(6#%&);�(�&7-�l���4�$0!�#%>C(L#%3'86!9$'>H(=z�>H8�3O-=$'(n*�8�;�(!N8�DHDC&7!9*:*�465G*w*�4�&.*�4�&�>C;�&�*�$O#�5G3�-/$2|/$0-/&�F6&)*9zM&)&)(u#^>C(�(�&}#%*�$2>C(�$0!N*w57(6-{-+865G3�;�>H8�*�&I!9r�!9*�&)<q!$O!�<I86#c4[!N<q5G3'32&);�*�4657(s$0!�#%>C<=<[>C(�32r.!N8?1�16>U!N&}-�l

����� �>, =t* �����4, ; 240� � 276 6�* .%2��K0324* � 6

�A3'*�4�>C8�DH4u$'*�4L5C!�F6&)&)(E#%>H(6#%3'8L-/&7-�*�465G*w*�4�&);�&p$O!�!9$'<=$23O57;�&)|/$0-/&)(6#^&:@B>C;�5�-+865G3�;�>C8�*�&.$'((�&)8�;J5G3�(?&)*9z�>C;���!M5G(6-I4/8�<q5G(6!^h/*�4?&w!N*�;�&)(�DH*�4=>7@�*�4�$O!M#%>C(L#%3'86!9$'>H(=<t8L!N*�F6&�*�&)<[1\&�;�&7-�F+r5G(E5G1?1�;R57$O!�573�>G@�*�4�&.zM&75G�+(�&7!�!N&7!�>G@�*�4�&.-+$O!�!9>+#%$O57*�$2>C(u<=&)*�4�>+-/>H3'>CDHrn$'(sDH&)(�&);J5G3Xh�57(6-s$'(

Page 67: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

E E ������������� ����������������� ��� ����� � ����������� � ������� �"!���# � � !������

$'*R!�571�1�32$O#)57*�$'>H(n*�>I#%>H(�(�&7#%*�$'>H(�$O!9*�<=>+-/&)30!%l��4?& �6;R!9*:1?;�>7|/$0!N>n*�>nF6&.<n5H-/&.#%>H(6#%&);�(6!�4�>7z zM&)3'3�;�&7!9&75G;J#c4?&);R!�465)|U&.F6&)&)(E5GF?3'&I*�>

!N$'<I8�305G*�& >e#%>HDC(�$2*�$'|U&�!9*�;�8L#%*�8�;�&��'h >K3'&}5G;�(?$'(�D ��5G(6- > 3'&7!9$'>C(?$'(�D ��$2(�*�4?&u!N*�86-/$2&7!t-+&7!�#%;�$'F6&7-5GF6>7|U&UlIm�*�$O!�16>U!�!9$'F�32&t*�465G*p*�4�&I!9$'<=1?3'$��L&7-�*J5C!N�?!w!N&)*�@B>H;:*�4�&I(�&)*9z�>H;��?!�5G;�&t$2({&7!�!N&)(L#%&-/$ &,&);�&)(/*�@B;�>H< *�4�>U!9&.1\&�;N@B>C;�<=&7-nF/r�4/8�<q5G(6!^h�57(6-s*�4657*w*�4�&.$2(/*�&);�(6573�!9*�;�86#%*�8?;�&.-+&)|U&)3'¨>C16&7-=F/r[#%>H(�(�&7#%*�$'>H(�$O!9*�(?&)*9z�>C;���!�$O!�8�(?3'$'�U&�57(/rI*�4L5G*�z�>H8�3O-n57;�$O!9&�$'([*�4�&�4+8�<n57(tF?;R5G$2(�l� 8?;�*�4?&);�<=>H;�&Uh7*�4?&�!9$'<=1�32$O!9*�$O#�>C16&);J5G*�$2>C(6573'$f!75G*�$'>C(L!�>7@�3'&7!9$'>H(�$'(�D f &Ul D?l'hC;�&)<=>7|/$2(�D�z�&)$2DC4+*R!>C;�<I8�3'*�$'1�32r/$2(�D�*�4�&)< F+ru5=!9$'(�DH3'&.(+8�<tF6&);^k�<n5)r=F6&.*�>H*R5G323'r�8�(�3'$2�U&w*�4�&.|H5G;�$'>H86!A@B>C;�<q!>G@�1�4+r�!9$O#)573�-�57<n5GDH&=*�4657*.#)57(~5G;�$O!9&t$2({*�4�&=4+8�<n5G(E#^>CDC(?$'*�$2|U&=!9r�!9*�&)<�l=��4�&[-/$O!�!N>+#%$05G¨*�$'>H(6!�*�4657*w465)|U&�F6&)&)(E;�&)16>H;�*�&}-�<n5)rnF6& ��8L5G3'$2*R57*�$'|U&�3'rn-/$'&,&);�&)(+*A@B;�>C< *�4�>U!9&t>HF6!N&�;�|U&7-$'(s4+8�<n57(6!%h,5G;�$O!9$'(�D=>H(�3'r�*�4�;�>C8�DH4u*�4�&I!916&7#%$��\#�#%>H<tF�$2(65G*�$'>H(6!�>G@�!N$2<=1�32&:*J5C!9��!^h�!N$2<=1�3'&(�&)*9z�>H;��?!�5G(L-�!9$'<=1?3'&�3'&7!9$'>C(?$'(�Dp*�&7#R4�(�$ ��8�&}!%l���4L5G*�$O!^h/*�4�&w>CF6!9&);�|U&7-[-/$O!�!N>+#%$05G*�$2>C(6!�<q5}r465)|U&�(�>C*�4�$'(?Dt*�>t*�&)3'3,86!�5GF6>C8?*w-/$O!�!N>+#%$05G*�$'>C(L!�$2(�4+8�<n57(6!%l

��4?&n!N&7#^>C(6-{1?;�>7|/$0!N>n*�>H86#R4�&7!:>H(~5�z�$0-/&);w$O!�!N8�&g¡�$'*p#%>H(6#%&);�(6!:*�4�&t16>7z�&�;�>G@�-+$O!�!9>C¨#%$O57*�$'>H(6!�$'(~;�&75C!9>C(�$2(�D~5GF6>H8�*t<[>+-/8�3O57;I!N*�;�86#%*�8�;�&n$2(�DH&)(�&);J5G3Xh�*�4657*.$O!^h�$2(�4+8�<n5G(L!�5C!z�&)323olE��4�&�-/>C8?F�3'&�-/$0!�!N>+#^$O5G*�$'>H(6!:@B>C8�(L-�$'(y*�4�&�!N$2<t8?3O5G*�$'>H(6!w-/&7!�#^;�$'F6&7-~57F\>7|U&�#)57(�F6&$'(+*�&);�1�;�&)*�&7-t$2(�*9zM>.z�5)r�!^¡�5C!�&)|+$O-/&)(L#%&�*�4L5G*�5.-/865G3�;�>H8�*�&w&)�+$O!9*R!�$2(s#^>C(�(�&}#%*�$2>C(�$0!N*�(�&)*�¨z�>C;���! f *�4�&w$'(+*�&);�1�;�&�*R5G*�$'>H(�&�<=1�465H!N$"!�&7-t!9>t@X5G;^k�>H;)h�DH$'|U&)(n*�4?&=�GaRa�] �A`6WXVOQUT�*�4L5G*�(�&)8�;J5G3(�&)*9z�>H;��?!:57;�&n!9$'(�DH3'&Uh�8�(?$��6&7-E<=&7#R465G(�$0!N<[!%h�*�465G*�-/>C8?F�3'&[-/$O!�!N>+#%$05G*�$'>C(L!.5G;�&I8�(�;�&)3'$05GF�32&$'(6-/$0#)5G*�>C;J!A>G@�<=>+-/8�305G;�$2*9rUh��%Z�PR�U]Ca7Z�*�4?&)ru57;�$O!9&.$'(E-/$0!N*�;�$'F?8�*�&7-u!9r�!9*�&)<q!A!986#c4E5H!�(�&)8�;J5G3(�&)*9z�>H;��?!%l

��4?&{305G*�*�&);=$2(/*�&);�1�;�&)*R57*�$2>C(£$O!=*�4�&{>H(�&u@X5}|U>H8�;�&}-�F/r£;�&7!N&757;R#R4�&);J!tz�4�>�4L5}|U&u8L!N&7-3'&7!9$'>C(?$'(�D[!N*�86-/$'&}!A>C(y-/$O!9*�;�$'F�8�*�&7-s!9r�!9*�&)<q!A5H!A165G;�*w>G@�5G(7> 5G*�*J5C#R�l�6>C(E*�4?&.-/$0!�!N>+#^$O5G*�$'>H(<=&)*�4?>+-/>C32>CDCr f &Ul D?l'h   5G;�*�>C;�$oh�i�j� � � �E>U>+-�h�i)j� n#�kJl!��|U&)([��8�323'$'(L5G;�$05�5G(L-���465G*�&); f i�jCj � k-/&7!N$2DC(�&}-t*�4�&�$';�!9*�86-+rtz�$2*�4=*�4�&�&)�+1�;�&}!�!�$2(/*�&)(+*�>7@�-+$O!�#^;�&7-/$2*�$2(�Dp-/>C8�F?3'&w-/$0!�!9>+#%$O57*�$'>H(6!�5C!5�*�>U>C3�@B>C;�8�(6#^>G|U&�;�$'(?D�<=>+-/8?3O5G;�$'*9rUl

  86#c4E5[#c4657;�DH&.z�>C8?3O-sF6&=5[!N&);�$'>C8L!�$2(6-/$0#%*�<=&�(/*M>G@M*�4�&I-+$O!�!9>+#%$O57*�$2>C(E<=&)*�4?>+-/>C32>CDCrghF\&}#)5G86!9&�*�4?&�3'>HDC$O#�>G@�*�4�&�<=&�*�4�>+-/>H3'>HDCrI$'(6#%3286-/&7!�*�4�&A$2<=1�32$O#%$2*�5H!�!N8?<=1�*�$2>C(=*�465G*�-/>C8?F�3'&-/$O!�!N>+#%$05G*�$2>C(6!wz�$'323�(�>C*p57;�$O!9&t$2({(?>C(�¨B<=>+-/8�305G; >e-+$O!N*�;�$2F�8�*�&}-l��!Nr?!N*�&)<n! f9  46573'3'$0#%&Uh�i�j� � �kRl�A>7z�&)|U&);�hC*�4?$O!�5G32*�&);�(65G*�$'|U&�$'(+*�&);�1�;�&�*R5G*�$'>H(=>G@�*�4�&�;�&7!98�3'*J!w�Cd a�Q�;�&)3'$2&7!�>C(�5.#%>H(/*�;�>7|U&);R!9$O573

Page 68: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � �'����� ��� � !���#1� � �D��� ���5� � � ��� ����� � � � E �

5C!�!98�<=1�*�$'>H(�h�(65G<=&�3'rn*�4657*p#%>C(�(?&7#%*�$2>C(�$0!N*�(?&)*9z�>C;���!�465)|U&.(�>n$2(/*�&);�(6573�<=>+-/8?3O5G;p!9*�;�8L#%¨*�8�;�&Uh/z�4�$0#c4n$0!�1�;�&7#^$O!N&�3'r.*�4?&:$0!�!98�&pm�5G< *�;�r+$'(�D.*�>I5C-�-/;�&7!�!�4�&);�&Ul

  86#c4E3'>HDC$0#)5G3�#^>C¨X-/&)16&)(6-/&�(6#%$'&}!�1?;�>7|/$0-/&I5s#^>CDC&�(/*p-/&)<[>C(6!9*�;R57*�$2>C(E>G@�*�4�&Iz�&757�/(�&}!�!>G@.*�4�&E-/$0!�!N>+#^$O5G*�$'>H( <=&�*�4�>+-/>H3'>HDCr,¡{$'*�#)57(�(�>H*)hA$2(£$'*J!N&)3e@�h�&�|U&)(�;�&7!N>H3'|U&u*�4?& ��8�&}!N*�$2>C(>G@�z�4?&)*�4�&�;�5�-/86573�;�>C8�*�&t&��/$0!N*R!�$2(v5n#%>H(�(�&7#%*�$'>H(�$O!9*:(?&)*9z�>C;���h�&)|U&�(u*�4�>H8�DC4v*�4�&I<=>U!9*!N$'DH(�$��\#)5G(+*�16>U!�!N$'F?3'&.;�&}!N8�32* f $Xl &Ul2h65�#^3O5C!�!N$0#)5G3�-/>C8?F�3'&[-/$O!�!N>+#%$05G*�$'>C(u$0!�5n!N$2(�DC32&.(�&)*9z�>H;��6k465C!=F6&)&)(�5H#c4�$2&)|U&7-�l¦��4?&{F65H!N$0#s1�;�>HF�3'&)< $O!t*�465G*�-/>H8�F�32&E-/$O!�!N>+#%$05G*�$2>C(6!n57;�&EF�8�*n57(VOT�§UVO_cZ�P%W�<=&75H!N8�;�&.>G@�<[>+-/8�3O57;�$2*Nr,¡A*�4�&)r�-/>n(�>C*p$'(u*�4?&)<n!N&�3'|U&7!�DH$'|U&I5G(+rs$2(6-/$0#)5G*�$'>C(E>G@4�>7z *�4?&t<=>+-+8�3O57;�$'*9rn$O!�$2<=1�3'&�<t&)(U*�&7-n5G(6-,h�$'(L-/&)&7-�h,(�>n$'(6-/&�1\&�(6-/&)(+*w5C!�!N8�;J5G(6#^&n5C!w*�>z�4�&)*�4?&);�5G(+rn!N8L#c4n$'(+*�&�;�(6573�<=>+-/8?3O5G;�$'*9rI&)�/$0!N*J!�5G*�5G323ol

��(�&.<[$'DC4+*�5C!9�sz�4+rUh6$¤@M-/$0!�!9>+#%$O57*�$'>H(6!w5G1�16&757;w*�>=F6&.>G@�!986#c4�3'$2<=$'*�&7-t86!9&.$'(u-+&)*�&);�¨<=$'(�$2(�Dw*�4�&�<=>+-/8�305G;�!9*�;�86#%*�8?;�&w>G@�!N$2<=1�3'&�#^>C(�(�&}#%*�$2>C(�$0!N*�(?&)*9z�>C;���!^h�-/>.*�4�&)rI465)|U&w!N8L#c45�|U&�(�&);R57*�&7-w16>U!N$2*�$2>C(I$'([#%>CDH(�$'*�$'|U&�(?&)8�;�>H16!Nr?#R4�>C32>CDCr $ ��&7!N1�$2*�&�*�4�&)$';�3O5H#c�p>G@�1\>7zM&);�5G(L-;�&)32$O5G(L#%&.>C(~(+8�<=&);�>C86!�5H!�!98�<=1�*�$'>C(L! fN  465G323'$O#^&Uh�i)j� � �kJh�*�4�&)ru;�&�<n5G$2(u>C(�&=>7@�*�4�&[<=>U!9*1\>7zM&);N@B8�3�*�>U>C30!w5}|H57$'3O57F�3'&.*�>n*�4�&I#%>HDC(�$2*�$2|U&�(�&)8?;�>C1L!Nr?#c4�>H3'>HDC$O!9*w$'(u*�4?&=-/$��n#^8�3'*�*R5H!N�u>G@-/&)*�&�;�<=$2(�$'(�D�*�4�&�@B8�(L#%*�$2>C(6573+5G;R#R4�$2*�&7#%*�8�;�&�>7@6*�4�&�4+8�<n57(:F?;R5G$2(�l � &7!9&75G;J#c4�&�;R!�5G;�&�305G;�DH&)3'r8�(65GF?3'&I*�>�-/$';�&7#%*�3'r�5C#)#^&7!�!A>H;�<n57(�$'1?8�3O57*�&�*�4�&.3'$2|/$2(�D=F�;J5G$2({F6&7#)5786!N&I>G@�*�&7#R4�(�$0#)5G3�5G(L-&)*�4�$0#)5G3+;�&}5C!N>H(6!��657(6-.&)|U&)(�$e@�*�4�&)r�zM&);�&�57F�3'&ghC*�4�&�$'(+*�&�;�(6573�#%>H<=1�32&)�/$2*9r�>G@�*�4�&�>H;�DU57(=&)�+¨#%&)&7-�!�*�4�&�#)5G1L5GF�$23'$'*�$'&7!�>G@�#^8�;�;�&)(/*�5G(6573'r+*�$O#�5G36*�>U>H3O!�57(6-�@X5C#%8�32*�$2&7!%l���4�&)r�4L5}|U&�(�>p#R4�>C$0#%&F�8�*�*�>w;�&�3'r�>H(n5w#%>U57;R!9&)3'r+¨�DH;R57$'(�&7-,h�$2<=1�;�&7#%$O!9&Uh75G<IF�$2DC8�>H86!�<=&)*�4?>+-/>C32>CDCrgh�*�465G*�$2(/|U>H3'|U&7!z�5G$2*�$2(�Ds@B>C;I$'(6-+$'|+$O-/86573�1657*�$2&)(/*J!�*�>E1�;�&}!N&)(+*.z�$'*�4�32&7!N$2>C(6!.57(6-�<[&75C!98�;R57F�3'&n#^>CDC(?$'*�$2|U&-/&��,#%$2*R!^l

�£4?$'3'&�!N$2<=$'305G;�-/$0!�!N>+#^$O5G*�$'>H(v!9*�86-/$2&7!A465)|U&.F6&)&)(E#�5G;�;�$'&7-s>H8�*�>H(v#%>H(�(�&7#^*�$'>H(�$O!9*�(�&)*�¨z�>C;���! f 5C!�;�&)|/$2&)z�&}-�5GF6>7|U&CkJhC$'*�zM>C8�30-�F6&�5�<=$0!N*R57�U&�*�>�*�4�$'(��p*�4657*�*�4�&�57(65G32r�!9$O!�>G@,*�4?&7!N&(�&)*9z�>H;��?!�(�&)&7-w&)(6-�*�4�&);�&gl�m�@6z�&�#^>C(6#%&�$'|U&�>G@�#%>H(�(�&7#%*�$'>H(�$O!9*�(�&)*9z�>H;��?!�5H!�!N$'<[1�3'$��6&7- >e57(�¨$'<n573\<[>+-/&)3O!��/>7@�*�4�&wF�;R57$'( f �u#G��32>U!9�U&)rUh6i)jHj/iGkJh\*�4�&w(�&)�+*�3'>HDC$O#�5G3�!N*�&)1n$O!�*�>IDC>IF\&�rU>C(6-*�4�&.$2(6-/$';�&7#%*�*�&7#c4?(�$ �U8�&7!�@X5)|U>C8�;�&7-s!9>q@X57;)h�57(6-E-/$';�&7#%*�32r=&)�?5G<=$2(�&p5G(6-u<n57(�$'1�8?3O5G*�&w*�4�&>CF�¢9&7#%*M>G@�!9*�86-/rgl A>7z *�465G*�$2*�4L5C!�F\&�&)(n!N4?>Gz�(n*�465G*�-/>H8�F�32&w-/$O!�!N>+#%$05G*�$'>C(L!�#)5G(�5G;�$O!9&�$'(#%>C(�(?&7#%*�$2>C(�$0!N*�(�&)*9z�>H;��?!%h6;�&7!9&75G;J#c4?&);R!�#�5G(u*R57�U&�*�4�&�(�&��/*w!9*�&)1E57(6-~§UVO_cZ�P^W�d � 5C#�#%&7!�!�*�4�&$'(+*�&);�(65G3�;�&)1�;�&7!N&)(+*R57*�$2>C(6!�*�>p!N&)&�$¤@,*�4?&A$2<=1�3'$2&7-�<=>+-/8�305G;�!9*�;�86#%*�8?;�&�5C#%*�865G323'r�&��/$0!N*R!^hU5G(L-

Page 69: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

E ( ������������� ����������������� ��� ����� � ����������� � ������� �"!���# � � !������

$¤@�!9>�h�4�>7z�$2*:$0!�$'<=1�32&)<I&)(/*�&7-�l � !N$'(?Ds(�&)8?;R5G3�(�&�*NzM>C;���!�1�;�>G|+$O-+&7!�;�&7!9&75G;J#c4�&�;R!A@B>C;p*�4�&�6;R!9*�*�$2<=&�z�$2*�4E5n!N$2<=1�3'$��6&7-=57(65G32>CDH8�& >KF?;R5G$2(<�6*�4657*:*�4�&)r�#)5G(E5H#)#%&7!�!:57(6-s<n57(�$'1�8?3O5G*�&z�$'*�4�!�#%$'&)(+*�$��,#�;�$'DH>C8�;�h\F?8�*�z�$'*�4�>C8�*�*�4?&:1?;R5C#^*�$O#�5G3�57(6-�1?;�>+#%&7-+8�;R573�#%>C<=1?3'$O#�5G*�$2>C(6!^l

��3'*�4?>C8�DH4u*�4�&.86!9&t>7@M(�&)*9z�>H;��?!A<=$'DH4/*�!9>C32|U&.*�4�&I-/$��n#^8�3'*�$'&7!�>7@�5C#�#%&7!�!^h�&)*�4�$O#)!�5G(L-<n5G(�$21�8�305GF�$23'$'*9rUh�#%>C<[1�3'&)�+$'*9ry!N*�$'3'3�1?;�&7!9&)(/*J!t5E1�;�>HF�3'&)<�l���|U&)( *�4�>H8�DC4 #%>H(�(�&7#%*�$'>H(�$O!9*<=>+-/&)30!�5G;�&�#%>C(6!9$O-/&�;R5GF?3'r~!9$'<=1�32&);�*�465G( *�4�&n4+8�<n5G(yF�;R57$'(�h�3O57;�DC&n(�&�*NzM>C;���! f !N8L#c4 5C!  &)$O-+&)(/F6&);�D�� �u#G��3'&)323O57(6-�h�i)j� CjUkw5G;�&I!N*�$'3'3�3O57;�DH&)3'r�F\&�rU>C(6-s*�4�&I5G(6573'r?!N$0!:57(6-u|/$0!N86573'$'¨!�5G*�$'>H(�*�&7#R4�(�$ �U8�&7!�5)|H5G$23O5GF?3'&w57*�1�;�&7!N&)(+*)l�mo(=*�4�&�(�&��/*�#c46571�*�&�;�m�8�(6-/&�;�*R57�U&w5G(�57(65G32r�!9$O!>G@�(�&)*9zM>C;��?!�*�;J5G$'(?&7-�>H( �U865C!9$';�&�DC8�305G;w*R5H!N�?!%h�F?8�*�*�>u!N$0-/&7!9*�&)1E*�4�&[#%>H<=1�3'&��/$2*Nr[$O!�!98�&[m;�&7!9*�;�$0#%*�<IrI!N*�86-/rn$'(?$'*�$05G323'r.*�>[!N$2<=1�32&A(�&�*NzM>C;���!�*�;R5G$2(�&7-=>C(�!9$'<=1�32&A*J5C!9��!^l

mo( !N8?<=<n5G;�rUh�*�4�&�(�h�$¤@�>C(�&�#%>H(6!N$0-/&);J!�*�4�&=;�&7!N8?3'*R!�>7@�32&7!N$2>C(�$2(�Du!9*�86-+$'&7!^h�*�4�&);�&q5G1�¨1\&}5G;R!�*�>pF\&�!N8�F6!9*R57(/*�$O5G3,$'(6-+$';�&}#%*�&)|/$0-/&)(6#^&�@B>C;M*�4�&�&)�/$0!N*�&)(6#%&�>7@�5G(=$2(/*�&);�(6573,-/865G3,;�>H8�*�&$'(y#%>C(�(?&7#%*�$2>C(�$0!N*�(?&)*9z�>C;���!^¡�-+$O!�!9>+#%$O57*�$2>C(6!p5G(6-{&�|U&)(E-/>C8?F�3'&[-/$O!�!N>+#%$05G*�$'>C(L!:465)|U&.F6&)&)(>CF6!9&);�|U&7-,l���4�&�;�&7!98�3'*J!t57;�&UhM4�>7z�&)|U&);�h�>C16&)( *�>~57<tF�$2DC8�>H86!�$'(+*�&�;�1�;�&)*R57*�$'>H(�hM5G(6-~*�4�&-/$O!�!N>+#%$05G*�$2>C(I<=&)*�4�>+-/>C32>CDHr.3O5C#R�?!�*�4�&�16>7z�&);�*�>w;�&7!N>H3'|U&�*�4?&A$0!�!N8?&�>C(�&�z�5)r�>C;M*�4�&�>H*�4�&�;)l�£4�$'32&�F?;R5G$2(£;�&7!9&75G;J#c4?&);R!.57;�&s@B>C;J#%&7-~*�>v<n57�U&n-/>vz�$2*�4�!N86#R4�$2(6-/$';�&7#%*.<=&}5C!N8?;�&7!.F6&)¨#)5G86!9&�>7@�5H#)#%&7!�!%h6<n5G(?$'1�8�305GF�$23'$2*Nrgh/#^>C<=1�32&)�+$'*9rI5G(6-n&)*�4?$O#)573�1�;�>CF�32&)<n!^h/(�&)8?;R5G3�(�&)*9zM>C;��?!1�;�&7!9&)(+*�;�&}!N&757;R#R4�&);R!�z�$2*�4=*�4�&�>C1?1\>H;�*�8�(�$'*9r=*�>.-/$2;�&7#^*�3'rI57(6-=$'(6-+&)16&)(6-/&)(+*�32r�$2(/|U&7!9*�$2DU5G*�&z�4�&)*�4?&);p5G(v$2(/*�&);�(6573�-/86573�;�>C8�*�&t&)�+$O!9*R!�$'(y!N$2<=1�32&�(�&)*9zM>C;��?!�*�;J5G$'(?&7-�>H( �U865C!9$';�&�DC8�305G;*R5C!9��!^l�mo(=*�4�&w(�&��/*M#R465G1�*�&);�m�8�(L-/&);�*J5G�U&w!986#R4n5G(�5G(L5G3'r?!N$0!�>7@�!9$'<=1�32&�(�&)*9z�>H;��?!�*�;R5G$2(�&7->C( �U865H!N$';�&)DC8?3O5G;�*J5C!9��!^l

Page 70: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����

��� ������� ��� � ����� � � � ��� � ��� ���

� ��� � 0�=F*"! � .10324* �

m�(£*�4�&u1�;�&)|/$2>C86!n#R465G1?*�&);J!=m�;�&)|+$'&)zM&7-�F6>C*�4 *�4�&y-/865G3�;�>C8?*�&y5G(6-�#%>C(?(�&7#%*�$'>C(?$O!N*q5G1�¨1�;�>g5C#R4�&7!�*�> �U865C!9$';�&�DC8�305G;.<n571�1�$'(?DU!%hM5G(L-�*�4?&)(~&)��57<=$'(?&7-�*�4�& ��8?&7!N*�$'>C( >G@�z�4�&)*�4�&);*�4�& f 5C!�!N8�<=&}-\kw#%>H(/*�;R5H!N*.F6&)*9z�&)&�(v*�4�&[*NzM>E5G1�1?;�>U5H#c4?&7!�$O![V'd'de]Ca�QU_ � ��*�4L5G*.$O!^h�z�4�&)*�4�&);#%>C(�(?&7#%*�$2>C(�$0!N*I(�&)*9z�>H;��?!.-/>�h�$2(�@X5C#^*)h�$2<=1�3'&�<=&%(+*p5G(£$2(/*�&);�(6573�-/86573�;�>H8�*�&n@B8�(6#%*�$'>C(L5G35G;R#R4�$2*�&7#%*�8�;�&gl

��4?&=$'(6-+$';�&}#%*�&)|+$O-/&�(6#%&.$'(y*�4�&I3'$2*�&);J5G*�8?;�& f @B;�>H<©3'&7!9$'>H(�$'(�D�!N*�86-/$'&}!�>7@�*�;J5G$'(?&7-{(�&)*�¨z�>C;���!Rk�!94�>7z�!�*�4657*�*�4�&);�&�$O!M5C#%*�865G323'r�.QU_RZ�&)|+$O-/&)(L#%&�@B>C;�*�4�&�&)�+$O!9*�&)(6#^&�>G@�5�-/86573�;�>H8�*�&$'(.#^>C(�(�&}#%*�$2>C(�$0!N*�(�&)*9z�>H;��?!�*�4657(.$'(.4+8�<n57(�!98�F�¢9&7#%*J!%hU57*�3'&}5C!N*�5C! @X57;�5C!�*�4?&�-/$0!�!N>+#^$O5G*�$'>H(<=&)*�4?>+-/>C32>CDCru$0!�#%>H(6#%&);�(�&7-�ln��4?$O!�#^>C(6#%3286!N$2>C(Ez�5H!�*�&)<=16&);�&7-sF+rE5s-/$0!�#%86!�!N$2>C(v>7@�*�4�&DC&)(�&�;R5G3?3'$'<[$'*R57*�$2>C(6!�>7@�$2(6-/$2;�&7#%*�<=&)*�4�>+-�!�!986#R4I5C!�-/$O!�!N>+#%$05G*�$'>C(L!%h+5G(6-I5G(I57;�DH8�<=&)(+*�*�465G*<=>C;�&n§UVO_cZ�P^W <[&)*�4�>+-?!A>G@�5G(6573'r?!N$O!�#)5G(EF6&.86!N&7-s*�>n$'(+|U&7!N*�$'DU57*�&pz�4�&)*�4?&);w#%>H(�(�&7#%*�$'>H(�$O!9*(�&)*9z�>H;��?!�-/>�$'(:@X5H#%*�$2<=1�3'&�<t&)(U*�5�-/86573�;�>H8�*�&�5G;J#c4�$2*�&7#^*�8�;�&Ul�m�(p*�4�$0!�#R465G1�*�&);�!N86#R4.-/$2;�&7#^*<=&)*�4?>+-�!�5G;�&�1�8�;R!98�&7-w*�>�5C-�-/;�&7!�!�*�4�& ��8�&}!N*�$2>C(p>G@6z�4�&�*�4�&);�(�&)8?;R5G3+(�&)*9zM>C;��?!�-/&)|U&�3'>C1p57($'(+*�&);�(65G3�-+865G3�;�>C8�*�&UlI��4�;�>H8�DC4y*�4�&I86!N&.>7@�!9*R5G*�$O!9*�$O#�5G3'32r/¨BF65H!N&7-u|/$0!N86573'$f!75G*�$'>C(�<=&)*�4�>+-�!f >C(E3O57;�DH&);�(�&)*9zM>C;��?!ck�5G(6-E-/$';�&7#%*�|/$0!N86573�$'(L!N16&7#%*�$'>C( f >G@�!N<n573'3'&�;�(�&)*9z�>H;��?!ck�m�5G*�*�&)<=1?**�>�-/&)*�&);�<=$2(�&�z�4�&�*�4�&);w*�4�&);�&p$O!w5G(+rs$2(/*�&);�(L5G3�-/$O!9*�$'(L#%*�$2>C(u<n5H-/&�F6&)*9z�&�&)(u;�&)DH8�3O57;w5G(L-&)��#^&)1�*�$2>C(=1L5G*�*�&);�(L!�$2(�*�4�&w4�$O-?-/&)(=8�(?$'*�!N1L5C#%&p>G@�5�*�;R5G$2(�&7-=(�&)*9zM>C;��,l

��>n$'(+|U&7!N*�$'Dg5G*�&p*�4�$0!�$O!�!98�&Im�465)|U&I#c4�>g!N&)(u*�>n&)<=1�32>Gr[*�4�&na�V �.]�d �CWoVOQUT �tZJW b?Q7§UQCdeQRS � �

E �

Page 71: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

E ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

*�4657*�$O!^h�mA86!N&[5C!w&)|+$O-/&)(L#%&.<trn>HF6!N&);�|H5G*�$2>C(6!:@B;�>C<©&)<[1�$';�$O#)573�&)�/16&);�$'<=&�(/*J!�z�$2*�4E$'(6-/$2¨|/$0-/865G3�(?&)*9z�>C;���!^l�� (+8�<IF6&);�>7@�(�&)*9z�>H;��?!�zM&);�&w*�;R5G$2(�&7-�5G(6-n&)��57<=$'(?&7-=5}@B*�&);�*�;R57$'(�$2(�Dz�5C!w#%>H<=1�32&)*�&Ul�m�z�5C!A@B>C;J#%&7-u*�>=;�&7!N>H;�*w*�>n*�4�$O!A<[&)*�4�>+-+>C3'>HDCr f $'(L!N*�&}5C-u>G@�5=<=>H;�&p;�$'DH¨>C;�>H86!%h�<n57*�4�&�<n5G*�$O#)573'3'r+¨BF65C!9&7-n5G(6573'r?!N$O!Rk�F6&7#)5786!N&[#%>C(?(�&7#%*�$'>C(?$O!N*�(�&)*9zM>C;��?!�57;�&Uh�5G*�*�4�&1�;�&7!9&)(+*�*�$2<=&UhC*�>U>=#^>C<=1�32&)��*�>.*�4�>H;�>H8�DC4�32r�5G(6573'r?!N&�|+$O5.!9*R5G(L-�5G;J- f 32$'(�&}5G;%k�<n57*�4�&�<n5G*�$'¨#)5G3�*�&7#R4�(�$ �U8�&7!^l � &7!9&75G;J#c4?&);R!�57;�&�DC&)(?&);R573'3'rp8�(657F�3'&�*�>�1�;�&7-/$O#^*�*�4�&A>H8�*R#^>C<=&M>G@�(�&)*9zM>C;��*�;R57$'(�$2(�D�h�>H;�*�4?&=#R465G;J5C#%*�&);�$0!N*�$O#)!�>G@�$2(/*�&);�(6573�;�&�1�;�&7!9&)(+*R5G*�$'>H(6!%h�-/8�&I*�>n*�4�&t$2(65GF?$'3'$2*9rs>G@#%8�;�;�&)(+*�*�&7#c4?(�$ �U8�&7!�>7@�<I8�32*�$'|H57;�$O57*�&�57(65G32r�!9$O! ��z�4�$O#R4.57;�&�FL5C!N&}-�>H(.*�4�&���ZcT\Z^_��Cd ��VOT\Z��U_� Q7§/ZRd f ��5GFL5C#R4�(�$O#R�K� � $O-/&�3'3oh+i)j� � k �p*�>p#%>H1\&�z�$'*�4t*�4�&�(�>H(�3'$2(�&75G;�$2(/*�&);R5H#%*�$2>C(6!�z�$'*�4�$'(#%>C(�(?&7#%*�$2>C(�$0!N*�(�&�*NzM>C;���! f ��5G(6!9>C( ����8�;�;�h�i)jCj)?�kJlAmo(�!N4�>H;�*)h6(�>[!�57*�$O!o@X5C#%*�>C;�r�<[>+-/&)3�>G@#%>C(�(?&7#%*�$2>C(�$0!N*M3'&757;�(�$2(�D.465C!�F6&)&)(�#%>C(6!9*�;�86#%*�&}-qF6&)rU>H(6-=*�4�&w(�&�*NzM>C;���!�*�4�&)<n!9&)3'|U&7!^l

� >H;�*�4�$0! ;�&75C!9>C(�hU*�4�&�!9$'<I8�3O57*�$'>H(w<=&)*�4?>+-/>C32>CDCrw$0!�!9*�$'323/*�4�&�<q5G¢9>C;�$'(+|U&7!N*�$'Dg5G*�$2|U&�*�&}#c4�¨(�$ �U8�&.86!9&7-�$2(E#%>C(?(�&7#%*�$'>C(?$O!N*�;�&7!9&75G;J#c4�l �£4�$'32&.&)<=1�$2;�$O#�5G3�*�&}#c4�(?$ �U8�&7!�!N86#R4E5C!p!N$'<I8�305G¨*�$'>H(6!�465)|U&A*�4�&�-/;R5)z�F65H#c�.>7@�F6&)$'(?D:8?(65GF�32&�*�>w1�;�>7|/$0-/&�*�4�&�>C;�&�*�$O#�5G361�;�>U>7@X!�>H;�#%>H(6#%3'8L!N$'|U&;�&7!98�3'*J!%hC*�4�&)rI5G;�&�!N*�$'3'3?86!N&%@B8?3/@B>C;�&)�+1�3'>H;R57*�>C;�r.z�>H;��.$'(I5�;�&)3O57*�$'|U&�3'r�$2<=<n5G*�8�;�&��6&�3O-.!N8L#c45C!.#%>H(�(�&7#%*�$'>H(�$O!9*:<[>+-/&)3'32$'(�D?l ��(�&t<I86!9*)h�4�>7z�&)|U&�;)h�F6&n5)z�5G;�&[>G@�*�4?&=<=&)*�4�>+-/>C32>CDH$O#)5731�$'*9@X5G3'30!�$'(+|U>C32|U&7-�$2(s86!9$'(�D[!N8L#c4�5G(E571�1�;�>U5C#R4�h,5G(6-n;�&7#^>CDC(?$"!)&w$'*J!�$'(+*�;�$'(6!9$O#A32$'<=$2*R5G*�$'>H(6!%l��4�&7!N&w32$'<=$2*R5G*�$'>H(6!�z�$'3'3,F6&.-/$0!�#%86!�!N&7-=$2(s-+&)*R57$'3�305G*�&);)l

� ��� �� �727. �K0324* � 6

��!�5�1?;�&%@X5H#%&�*�>�*�4?&�-+&)*R57$'3'&}-:!9$'<I8�3O57*�$2>C(6!65G(L-�!N*J5G*�$O!N*�$O#)573+5G(6573'r?!N&7!�>G@L(�&)*9z�>H;���;�&)1�;�&7!N&�(�¨*R5G*�$'>H(6!�-/&7!�#%;�$2F6&7-s4�&);�&Uh�m�F6&)DH$'(uF+r�-/$O!�#%86!�!9$'(�D[*�4�&.$0!�!N8?&7!�5G*�!N*R57�U&Ulw�A(�5G1�1�;�&7#%$05G*�$2>C(>G@w*�4�&)$';I$'<[1\>H;�*J5G(6#%&nz�$23'3�4�&)321�*�4�&s;�&75C-/&�;t*�>{16&);J!N&)|U&);�&n*�4�;�>C8�DH4 *�4�&u-/&�*R5G$23'&7- f F�8�*(�&7#%&7!�!�57;�r6k�<=$'(+8�*�$05G&�>G@�!N$2<t8�305G*�$'>C(L!%l

��4?&:$0!�!98�&p5C-�-/;�&7!�!9&7-�4?&);�&w$O!�*�4�&�@B>C323'>7z�$'(�D?¡

�A>�@B&)&7-U@B>C;�z�5G;J-�#^>C(�(�&}#%*�$2>C(�$0!N*�(?&)*9z�>C;���!�-+&)|U&)3'>H1=5.-+865G3�;�>C8�*�&�@B8?(6#%*�$2>C(65735G;J#c4�$2*�&7#^*�8�;�&A*�>t$2<=1�3'&�<t&)(+* �U865C!9$';�&)DC8�305G;�<n571�1�$2(�DU!%$

��(�&n<=$2DC4+*�F6&n*�&)<[1�*�&7-E*�> ��8�&}!N*�$2>C(~*�4?&�;�&)3'&�|C57(6#%&=>7@p!N8L#c4 5u1�8�;R!98�$'*�¡s5s;�&7!N8?3'*&)$'*�4�&);�z�5}r�<=$'DH4/*�F\&[-/&)<[>C(6!9*�;R57*�&7-s$2(v5EPRQUT�T6Z�P%WoVOQUT?V¤a^W�(�&�*NzM>C;���h�F�8�*wz�4657*�16>U!�!N$2F�3'&

Page 72: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� �#1� ������� � � � EUj

F\&}5G;�$2(�D.#^>C8�30-t*�4657*�;�&7!98�3'*�465)|U&�>H(=*�4?&�8�3'*�$'<n57*�& f 16!Nr?#c4?>C3'>HDC$0#)5G3Bk��U8�&7!9*�$2>C(=>7@�$2(/*�&);�&7!9*)h(65G<=&�3'rwz�4�&)*�4�&);�b?] �.�UTUa�&)<=1?3'>7rp5�-/865736;�>C8?*�&w57;R#R4�$'*�&7#%*�8?;�&�@B>H;�!986#c4I<n571�1�$'(?DU! $n�M57(5G(+r=16!Nr?#R4�>C32>CDC$0#)5G3�$2<=1�32$O#)57*�$'>H(6!�F6&�-+;R5)z�(�@B;�>C< #%>H(�(�&7#^*�$'>H(�$O!9*�!9$'<I8�3O57*�$'>H(6! $

��>H3'*�4�&75G;�* f i�jCj/EU5�k�-/>U&7!A(?>C*w*�4�$2(���!N>?l �A&�5G;�DC8�&7!�*�4657*�(�&)*9z�>H;��?!�5G;�&I5GF�32&�*�>=$'<=¨1�3'&)<[&)(/*�<n5G1�1?$'(�Dg!�$'(n5�305G;�DH&w|C57;�$2&)*9rt>7@�z�5}r?!%h6#^>C(6!9*�;�8L#%*�$2(�D�@B8�(6#%*�$'>H(65G3�5G;R#R4�$2*�&7#%*�8�;�&}!��8�$2*�&�-/$ &,&);�&)(/*�*�>=*�4�>U!9&=5H#c4�$2&)|H5GF�32&�F+rs4+8�<n57(6!%l �A&�(6#%&Uh6*�4�&.&��/$0!N*�&�(6#%& f >C;�(?>C*%k�>7@�5-/865G3�;�>C8�*�&=$'( 5sDH$'|U&)(y#%>C(?(�&7#%*�$'>C(?$O!N*p<=>+-/&)3 �E$'(6!9>G@X57;I5C!�*�4L5G*.&)�+$O!9*�&)(6#^&=#)57(~F\&n&7!9¨*R5GF?3'$O!94�&7- �Ez�>H8�3O-{;�&)|U&7573�(�>C*�4�$'(?DE5GF6>C8�*.*�4�&t@B8�(L#%*�$2>C(6573�57;R#R4�$'*�&7#%*�8�;�&I-/&�|U&)3'>H1\&}-�F+r4/8�<q5G(6!^l

��!Am�465)|U&�5G;�DH8�&7-n$'(s;�&7!N16>H(6!N&.*�>s��>C32*�4�&757;�* f ��5G�+�U&);)h�i�jCj/E/kRh,*�4�&p1\>g!�!9$'F�$23'$'*9r=*�465G*#%>C(�(?&7#%*�$2>C(�$0!N*p(�&)*9z�>H;��?!:<n5)ru-+&)|U&)3'>H1~5G32*�&);�(65G*�$'|U&.@B8�(6#%*�$'>H(65G3�5G;R#R4�$2*�&7#%*�8�;�&}!�*�>u*�4�>g!N&86!N&7-=F+rt4+8�<n57(6!�-+>U&7!�(?>C*�<=&757(=*�4L5G*�#%>H(�(�&7#%*�$'>H(�$O!9*�<=>+-/&�3O!�4L5}|U&�(�>I#%>C(+*�;�$'F�8?*�$'>H(n*�><n5G�U&�*�>n#%>HDC(�$2*�$'|U&w*�4�&)>C;�rUl���4�&�>H8�*R#^>C<=&w>G@M*�4�&.!9&75G;J#c4n@B>C;�5=-/86573�;�>C8�*�& � V'd'd6$'<=1L5C#%*#%>C(6!9$O-/&�;R5GF?3'r�>H(:*�4�&M-/86573/;�>C8�*�&�-+&)F65G*�&Uh7z�4�&)*�4?&);�5�-/86573U;�>C8?*�&�$0!\@B>C8�(L-�$2(w*�4�&�(�&)*9zM>C;��?!8�(6-/&);p#%>H(6!N$0-/&);J5G*�$2>C(v>H;w(�>C*�ln��4�&t*9zM>s16>U!�!N$'F?3'&I>C8�*J#%>C<=&}!�z�$23'3�(?>Gz�F6&[-/$O!�#%86!�!N&7-u$'(*�8�;�(�l

* ���6���� +�������� 2������� \���� +"�����^��w �2����

mX@\5:-+865G3�;�>C8�*�&�$O!�-+&)*�&7#^*�&7-w$'(�*�4�&�(�&)*9zM>C;��?!�#%>H(6!N$0-/&);�&7-�h7*�4�&)(.*�4�$O!�;�&7!98�3'*�zM>C8�30-.5G32<=>U!9*#%&);�*J5G$2(�3'r�F\&q!N&)&)(y5C!p5�16>7z�&);9@B8�3�|/$2(6-/$0#)5G*�$'>C(E>G@�*�4�&[-/865G3M;�>H8�*�&I*�4�&�>C;�rgl �A(?&t>7@�*�4�&!N*�;�&)(�DH*�46!=>G@�*�4�&y-/86573w;�>C8?*�&E5G1?1�;�>g5C#R4$'(£*�4�&{1L5C!N* f $ol &gl'h�$2( *�4�&~i)j � ? � !s57(6- &757;�3'ri)j� )? � !ck�z�5H!�*�4�&A305C#R��>7@�5G(+r=#%;�&7-/$2F�3'&�5G3'*�&);�(L5G*�$2|U&�*�4�&�>C;�r f z�$2*�4I*�4�&�16>U!�!N$'F?3'&�&)�?#%&)1?*�$'>H(>G@�5G(L5G3'>HDCrI*�4�&�>C;�r � �3286!N4��U>?h�i�j � jUkRl���>C(�(?&7#%*�$2>C(�$0!N*�>e!9$'(�DH3'&�;�>H8�*�&��+<=>+-/&)30!�#%>H(6!N*�$'*�8?*�&7-*�4�& �6;J!N*w!9&);�$2>C86!�5G(6-uz�>H;��H5GF�32&.#R465G323'&)(?DC&�*�>=*�4?&I-/865G3�;�>C8?*�&.*�4?&)>C;�r���F�8�*�$¤@�$2*w#)5G(uF6&!N4�>7z�(s*�465G*�#%>H(�(�&7#%*�$'>H(�$O!9*�<=>+-/&)30!�5G;�&gh�$'(=@X5C#%*�h�*�4�&�<n!N&)32|U&7!�-/86573�;�>C8?*�&.!9r�!9*�&)<q!%h/*�4�&)(*�4�$0!�;�&}!N8�32*�z�>H8�3O-=&T&,&7#^*�$'|U&�3'r�&�3'$'<[$'(657*�&�#^>C(�(�&}#%*�$2>C(�$0!N< 5C!�5G(�573'*�&�;�(657*�$'|U&�1�;�>C16>U!9$'*�$2>C(�l

m�@ #%>C(�(?&7#%*�$2>C(�$0!N*M(�&)*9z�>H;��?!�zM&);�&�@B>C8?(6-t*�>I!916>C(+*R5G(?&)>C86!93'r[5G(6-=$2(6-/&)16&)(6-+&)(/*�3'r�>e#%>H(�¨!N*�;�86#%*4��5u-/86573�;�>H8�*�&�5G;J#c4?$'*�&}#%*�8�;�&Uh�z�$2*�4�>H8�*I!N8L#c4 5s*�&�(6-/&)(6#^r{F6&)$2(�Du&)�+1�3'$0#%$'*�3'rsF?8�$'32*$'(�h+*�4�$0! �6(6-+$'(�Dpz�>C8?3O-n!N*�;�>C(?DC3'r[!N8?1�16>C;�* f F?8�*�F+rt(?>.<=&75G(L!�1?;�>7|U&Ck�*�4�&w5H!�!N&�;�*�$2>C(=*�465G*-/865G3M;�>H8�*�&�5G;J#c4?$'*�&}#%*�8�;�&7!�57;�&n*�4�&[>C(�32r{|+$O57F�3'&I<=&757(6!�>G@�$'<=1�32&)<I&)(/*�$e(�D �U865C!9$';�&�DC8�305G;

Page 73: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ? ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

<n5G1�1?$'(�Dg!%l�@B8�;�*�4�&);�F6>U>U!N*w*�>=*�4�&�-/86573�;�>H8�*�&p*�4�&)>H;�rn@B;�>C< !986#c4�5 �6(6-+$'(�D=zM>C8�30-�F6&.*�4L5G*�$'*

&7!N*J5GF�32$O!N4?&7!�*�4657*�5t-+865G3�;�>C8�*�&�57;R#R4�$'*�&7#%*�8�;�&�PRQU]�d §:F6&:$2<=1�32&)<t&�(/*�&)-�$2(s5I#%>H(�(�&7#%*�$'>H(�$O!9*(�&)*9z�>H;��,l���4�$0! �L(6-/$'(?D{zM>C8�30-ª1?;�&7!98�<n5GF?3'ry5G3O!9> �yz�$'*�4v@B8�;�*�4�&�;=57(65G32r�!9$O! �vDH$'|U&n57($'(6-/$0#)5G*�$'>H(�>7@�b?Q � !986#R4u5G(�$'<=1?3'&)<I&)(+*R5G*�$'>H(=#%>H8�3O-nF6&.5C#R4�$2&)|U&7-�l   8L#c4�5t;�&7!N8�32*�z�>H8�3O-1�;�>7|+$O-/&�!N>H<=&n|H5G3'8L5GF�32&u#%328�&7!.>C(�4?>Gz 5E-/86573�;�>H8�*�&�<=$'DH4/*.F6&s$2<=1�32&)<t&�(U*�&7-u$'( *�4�&F�;R57$'(�h657(6-�16&);�465G16!�!N8?DCDC&}!N*�4/r+16>C*�4?&7!N&7!�>C(n4�>7z*�>I-/&)*�&7#%*�!N8L#c4�5.!N*�;�86#^*�8�;�&Ul

* ���6���� + � ���u � 2������� 6���� +"��� �%��: �2����

mX@�h�>H(~*�4�&n>C*�4�&);.4657(6-�h�$2*�zM&);�&=16>g!�!N$2F�3'&n*�>v!94�>7z"*�465G*I(�>E-/86573�;�>H8�*�&n&)�+$O!9*R!�$'(y*�4�&(�&)*9z�>H;��?!�#%>C(L!N$O-+&);�&7-s4?&);�&Uh�!N86#R4E5=;�&7!98�3'*�zM>C8�30-��6(6573'3'r�&7!N*J5GF�32$O!94{*�465G*p#%>H(�(�&7#%*�$'>H(�$O!9*(�&)*9z�>H;��?!�§UQ.#%>H(6!N*�$'*�8?*�&.5I|/$05GF�32&Uh\zM>C;��/$2(�Dn5G32*�&);�(65G*�$'|U&w*�>[*�4�&I-/8L5G3�;�>C8�*�&.*�4�&)>H;�rUl���!m�465)|U&.57;�DH8�&7-�$2({��46571�*�&�;�E�h6*�4�$0!�1?;�>C16>g!N$'*�$'>H(u465C!^h�57*�*�4�$0!�!N*J5GDC&gh�F/r[(�>=<=&757(6!�F6&)&)(&7!N*J5GF�32$O!N4?&7-�h7-/8�&�*�>�5�#%>C(+@B86!N$2>C(�>7@�32&)|U&)30!%¡��u5G(+r�;�&7!9&75G;J#c4?&);R!6465)|U&�<[$O!N*J5G�U&)(?3'r�5C!�!N8�<[&7-*�4657*�*�4�&M!N$2(�DC32&)¨B;�>C8?*�&�`�b � a�VOPR�Cd^5G;J#c4?$'*�&}#%*�8�;�&�>G@L5�#%>C(�(?&7#%*�$2>C(�$0!N*,(�&)*9z�>H;��w#)57(wF\&�&��U8657*�&7-z�$'*�4�5I!N$2(�DC32&)¨�;�>C8�*�&�¥�]/T�P^WoVOQUT��Cd657;R#R4�$'*�&7#%*�8�;�&Ul

��4?&v-/&�<=>C(6!9*�;J5G*�$2>C(£>7@.(�>�-/865G3w;�>C8�*�&UhA&)|U&�(£$¤@p>C(�32r£$'(£>H(�&{>7@.*�4�&{(?&)*9z�>C;���![m#%>C(6!9$O-/&�;)h/zM>C8�30-t;�&^@B8�*�&���>H3'*�4�&75G;�*\� !�!N*�;�>H(�D=#^3O5G$2<�*�4657*�5.-/86573�;�>H8�*�&w$0!�_cZ � ]/VO_RZ�§�*�>p$'<=¨1�3'&)<[&)(/*�#^>C<=1�32&)� ��8L5C!N$2;�&)DH8�3O57;�<n571�1�$'(?DU! f !986#c4E5H!:*�4�&.<n5G1?1�$'(�D[>G@ ��(�DH3'$0!N4E*�&)�+*w*�>!N16&)&7#R4�����>C32*�4�&757;�*�h�i�jCj/EU5�kJln��4�&I&7!N*J5GF�32$O!N4?<=&)(+*A>7@�*�4?&I#%>C(�(?&7#%*�$2>C(�$0!N*w571�1�;�>U5C#R4~5H!�5#%;�&7-+$'F�32&.5G32*�&);�(65G*�$'|U&I#%>H8�3O-u3'&}5C-s*�>�5 >e!N4?>Gz�-+>Gz�( � F6&)*9zM&)&)(u*�4?&t*9z�>n*�4�&)>C;�$'&7!^h�>C(E*�4�&$O!�!98�&I>G@�z�4?$O#R4v573'*�&�;�(657*�$'|U&p1�;�>7|+$O-/&}!�*�4�&IF\&}!N*p5C#)#^>C8�(+*w>G@wb?] �.�UT��U865C!9$';�&)DC8�305G;p<n5G1�¨1�$'(�Dg!%l���4�&�>C8?*R#%>H<=&�>G@�*�4�$0!�*�4�&)>H;�&)*�$O#)573�#^>C<=1657;�$0!N>C(.<[$'DC4+*�&)$2*�4�&�;�3'&75H-�*�>p5G(=>H8�*�;�$'DC4+*;�&�¢9&7#^*�$'>H(.>G@�>H(�&A>H;�*�4�&A>H*�4�&�;�5H!�5w1�3O5786!N$2F�3'&�<=>+-/&)3?>G@�4+8�<n57( ��8L5C!N$2;�&)DH8�3O57;�<n571�1�$2(�DU!^h>C;p5G32*�&);�(65G*�$'|U&)32r�*�>u5E§/ZRdeVOT6Z��CWoVOQUT�>7@�*�4�&I!916&7#%$��\#t-/>H<n5G$2(6!A$2({z�4�$0#c4u&�$'*�4?&);�*�4?&)>C;�ru$O!!N8�16&);�$'>C; f &Ul D?l'h�$2*�<=$2DC4+*:F6&=@B>C8?(6-�*�465G*.*�4�&�-/865G3�;�>C8�*�&n*�4�&)>H;�rE$O!�*�4�&nF\&}!N*I5C#�#%>C8�(+*>G@�#)5G*�&)DC>H;�r£32&75G;�(�$'(�D?h�z�4�$'32&s*�4?&E#%>C(�(?&7#%*�$2>C(�$0!N*=<[>+-/&)3�$O!=!98�16&);�$2>C;=$2(£*�4�&u305G(�DH865GDH&-/>C<n57$'(�kJl

��>GzM&)|U&);�h *�4�&);�&t$0!:57(~$'<=16>C;�*R57(/*w3'>HDC$0#)5G3�1�;�>G|+$O!9>�¡.*�4?&t>H8�*R#%>H<=&I>G@�T�QCW��6(6-/$2(�DE5-/865G3�;�>C8?*�&E5G;J#c4?$'*�&}#%*�8�;�&�#%>C8�30-�F6&u$'(+*�&�;�1�;�&)*�&7-v$2(�*9z�>vz�5)r�!^¡�&�$'*�4?&);t(?>~-/86573�;�>H8�*�&

Page 74: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � �'����� � ��� � � �� � ����� � � ��� � �"!���# � � !���� �/i

&)�/$0!N*J!%h�>C;w*�4?&=#%8?;�;�&�(/*�<[&)*�4�>+-?!:57;�&I$'(6#�5G1657F�3'&.>7@�-/&)*�&}#%*�$2(�D=>C(?&Ul=��>�#%>C8�(+*�&�;:*�4�$O!^h�m-/&7!N$2DC(u<Irn&)�/16&);�$'<=&�(/*J!�!N>�*�4657*�*�4?&)rs<n57�U&:@B&)z�5H!�!N8?<=1�*�$2>C(6!�;�&)Dg5G;R-+$'(�Dn4�>7z�5n-/8L5G3;�>C8?*�&I$O!�$'<=1?3'&)<I&)(+*�&�- f 5H!:$0!:-+$O!�#^86!�!9&7-�F6&)32>7z�kRl=��!�zM&)3'3Xh�m�#R4�>U>U!9&=*�4?&t(�&�*NzM>C;��u5G(L-*�4�&w*R5H!N�n*�>IDC$2|U&�*�4?&�!9&75G;J#c4�5G(n>C1?*�$'<q5G3�#R465G(6#^&�>G@M!986#)#%&�&7-/$'(?D f &Ul�D�l'h?!N&)&p!9$'<I8�3O57*�$'>H( E$'(u��465G1?*�&); (UkRl

mo(E!98�<=<n57;�rUh6*�4�&[5GFL!N&)(6#^&.>G@�5n-/8L5G3�;�>H8�*�&Uh�$e@�&7!9*R5GF?3'$O!94�&7-sz�$2*�4y!N8 �q#%$'&�(/*�;�$2DC>C8?;)hz�>C8?3O- �L(65G323'rv&7!9*R57F�3'$0!N4£#^>C(�(�&}#%*�$2>C(�$0!N*.<=>+-/&�3O!.5C![5�;�&75G3�#%>C<[1�8�*R57*�$2>C(6573�5G3'*�&);�(L5G*�$2|U&*�>v*�4�&E-/86573:;�>C8�*�&u*�4�&�>C;�rgl mo*Iz�>C8?3O-£5G30!N>v@X5G30!N$e@Br ��>C32*�4�&}5G;�*4�K!=!9*�;�>C(�D #%305G$'< *�465G*�5-/865G3M;�>H8�*�&=$0!�;�&��U8�$';�&7-s@B>C;�$2<=1�32&)<t&�(/*�$¤(?Dn#%>C<[1�3'&)� �U865C!9$';�&)DC8�305G;p<n5G1�1?$'(�Dg!%h�*�4�&);�&)F/r*�4�;�>Gz�$2(�DI$'(+*�>I-/>H8�F�*�*�4�&�5C!�!9&);�*�$'>H(s*�4L5G*�*�4�&wF�;J5G$'( �.]ga^W�$2<=1�3'&�<t&^(/*M5I-/86573�;�>C8�*�&�57;�¨#c4�$2*�&7#^*�8�;�&�*�>.1�;�>+#%&7!�!�305G(�DH865GDH&�<n571�1�$2(�DU!^l�mo(=&)$2*�4�&);�#)5C!9&Uh/&}!N*R57F�3'$0!N4�$2(�D�*�4�&w&)�+$O!N*�&)(6#%&f >C;I>C*�4�&);�z�$O!N&Hk�>7@p5{-+865G3�;�>H8�*�&�$'( #%>C(?(�&7#%*�$'>C(?$O!N*.(?&)*9z�>C;���!.z�$'323�465)|U&�#%>C(6!9&��U8�&)(6#%&}!F\&�rU>C(6-I#%>C(?(�&7#%*�$'>C(?$O!N<�$2*R!9&)3¤@ �C$2*�z�$'3'3?$'<=165H#%*�>H(=>C8�;M*�4�&�>C;�$2&7!�>G@�4�>7z *�4�&�4/8?<n5G(IF�;R57$'($'<=1�32&)<I&)(U*R! �U865C!9$';�&�DC8�305G;�<n571�1�$'(?DU! f ��57�/�U&�;)h6i)jHj E/kJl

� ��� �>, � , =F,/6�, � 0 �K0324* � *�� � � ��� ��� * �-0$,

m�(E*�4?& �6;R!9*�1657;�*w>G@�<Ir�5G(6573'r?!N$O!�>7@�*�4?&t$2(/*�&);�(6573�;�&�1�;�&7!9&)(+*R5G*�$'>H(6!�>G@�;�&)DC8?3O5G;�5G(6-u&)�+¨#%&)1�*�$'>C(y165G*�*�&);�(6!%hMm:*�8�;�(~*�>u>H(�&s>7@�*�4�&=<=>g!N*.16>C1?8�3O57; f 5G(6-~#%>H<=1�3'&��\k �U865C!9$';�&�DC8�305G;<n5G1�1?$'(�Dn*R5H!N�?!:$2({*�4�&t32$'*�&);R57*�8�;�&U¡:*�4�&I<n5G1�1?$'(�Dn>G@ ��(�DH3'$0!N4v*�&)�/*�*�>u!916&)&7#R4�lnmo({1657;�¨*�$O#^8�3O57;)hMm�&)��57<=$'(?&=*�4�&�x�3O5G8?*=57(6- �u#G��3'&�3'3O57(6- f i)jCj � kI(�&)*9zM>C;�� f -/&7!�#^;�$'F6&7-v&757;�32$'&);^kz�4�$O#R4~!N8L#)#%&7!�!�@B8�323'ru$'<[1�3'&)<I&)(+*R!A*�4�&=<n571�1�$2(�D�@B;�>C< <=>H(�>U!9r/323O57F�$O# ��(�DC32$O!N4yz�>C;J-�!.*�>*�4�&)$2;�1�;�>H(/8�(L#%$O57*�$'>H(6!%l � 57*�&);�h�m�573O!9>.3'>U>C�[5G*�!N<n573'32&);�(�&)*9zM>C;��?!�*�4657*�465)|U&�F6&)&)(=*�;R5G$2(�&7-*�>.$'<[1�3'&)<[&%(+*�!N$2<=1�32&);)h+5G;�*�$��,#%$O573��U865C!9$';�&)DC8�305G;�<n5G1?1�$'(�Dp*R5H!N�?!%l

��4?&:DH>U573�>G@�<tr�5G(6573'r?!N$O!�$0!�*�>I-/&)*�&�;�<=$2(�&UhU5H!�@X5G;�5C!�16>g!�!N$2F�3'&wDH$'|U&)(I*�4�&�*�&7#R4�(�$ ��8�&}!5}|H57$'3O57F�3'&gh�z�4�&)*�4�&);w*�4�&.(?&)*9z�>C;���!wm�&)�?5G<=$2(�&w$'<=1�32&)<=&^(/*�5t@B8�(L#%*�$2>C(6573�-/86573�;�>C8�*�&=57;�¨#c4�$2*�&7#^*�8�;�&Ul���4657*A$0!%h+z�4�&)*�4?&);A*�4�&)r=<q5G1=;�&)DC8�305G;�5G(6-n&)�?#%&)1�*�$'>C([165G*�*�&);�(6!�|+$O5.-+$O!N*�$'(6#^*<=&7#R465G(�$0!N<n!�@B8�(6#%*�$'>C(L5G3'32r=#^>C;�;�&7!N16>H(6-/$'(?D=*�>I5.3'>U>H�/8�1�*R57F�3'&p5G(L-�5I!N&�*�>G@�;�8�3'&7!^l

�5G*�8?;R5G323'rUh�>C(�&q-/>U&7!�(�>H*�&)�+16&7#%*�*�>��6(L-v5G(~>CF+|+$'>C8L!:3'$0!N*p>G@�&)�?#%&)1�*�$'>H(6!�>C;I!N&�*�>G@;�8�32&7!�$2(u5t1L5G;R573'32&)3�-/$O!9*�;�$'F�8�*�&7-�(?&)*9z�>C;���hU¢986!9*�5H!A>C(�&.zM>C8�30-�(�>H*�&)�+16&7#%*�*�> �6(L-s*�4�&)<&)�/1?3'$O#^$'*�32rs1�;�&7!N&�(/*.$2(v*�4�&n4+8�<n57(�F?;R5G$2(�l~m�@�*�4�&�rv&)�+$O!N*�h�*�4�&�rvz�>H8�3O-vF6&n;�&)1�;�&7!N&�(/*�&7-

Page 75: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�n# ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

$'(~57(�&�(6#%>+-/&7-,h�-/$O!9*�;�$2F�8�*�&7-{<n57(�(�&); ��5G(6-v*�4?$O!�@X5H#%*�1?;�&7!9&)(/*J!�*�4�&[1�;R5H#%*�$0#)5G3�1�;�>CF�32&)<>G@�-/&)*�&}#%*�$2(�Ds*�4�&)<ulv��>C(?(�&7#%*�$'>C(?$O!N*.;�&7!N&}5G;R#R4�&);J!:465)|U&Uh�57*.*�4�$0!.!N*J5GDC&gh�5s|U&);�rE3'$2<=$'*�&7-8�(6-/&);J!N*J5G(6-/$2(�D~>G@�4�>7z©-/$0!N*�;�$'F�8?*�&7-�;�&)1�;�&}!N&)(+*R57*�$'>H(6!n5G;�&{*�>�F6&u$2(/*�&);�1�;�&)*�&}-�h�-/8�&E*�>*�4�&)$2;A4?$'DC4E-+$'<=&)(L!N$'>H(65G32$'*9r[5G(6-u$'(+*�&);�(65G3�#%>H<=1�3'&��/$2*NrHl���4�$O!�;�&7!9*�;�$0#%*�$2>C(�465C!�3'&}-�*�>[*�4�&1\>H1�8�305G;�$2*9r�>7@�VOT�§UVO_RZ�P%W�F\&�465)|/$2>C8�;J5G3�<=&75C!98�;�&}!�!N86#R4u5H!�-/$O!�!N>+#%$05G*�$'>C(L!%h�5H!�z�5C!A(�>H*�&7-n$'(*�4�&w1�;�&)|/$2>C86!�#R46571�*�&);�l

��>GzE*�4?&)(�h)z�>H8�3O-�$2*�F\&�16>U!�!N$2F�3'&�*�>�-+&)*�&7#^*�5G(p$'(+*�&);�(65G3g-/86573U;�>C8?*�& $[��4�&M-�57(�DC&);�4?&);�&$O!�*�4657*A$e@�>C(�&p<n5G�U&}!�8�(+z�57;�;R57(/*�&7-s5H!�!98�<=1�*�$'>C(L!�*�465G*�;�&7!N*�;�$0#%*�*�4�&�!N&757;R#R4n&)��#^&7!�!9$'|U&)32rUh5G(=&)�+$O!9*�&)(+*M-/86573�;�>H8�*�&�<=$'DH4/*�F6&�<=$0!�!N&}-�l���!�57(=&)�?5G<=1�32&�>G@�*�4�$0!�1�$'*9@X5G3'3Xh+m�z�$23'36F�;�$'&T�6r-/$O!�#%86!�!�x�3O578�*�57(6- �u#7��3'&)323O5G(L-l�K! f i)jHj � k�!N*�;R5G*�&)DCr=@B>H;�-/&�*�&7#%*�$'(�DI5I-/86573�;�>C8�*�&w$'(s*�4�&)$2;(�&)*9z�>H;��I*�4657*A<n5716!�*�&��/*M*�>[!N16&)&7#R4 � l

x�305G8�*�57(6- �u#G��32&)3'305G(6-��K! f i�jCj � k�!9*R57*�&7-�5C!�!98�<=1�*�$'>H(=z�5H!�*�465G*�5I-/86573�;�>C8?*�&wz�>H8�3O-F\&I$'<[1�3'&)<I&)(+*�&�-=F/ru*�4�&=!9&)*w>G@�iD? ?n4�$O-?-/&)(E8�(�$'*J!�a9`6deV'W�WXVOTCSEVOT/WXQ�W � Qu§UV¤a^WXVOT�P%W�Sg_�QU])`�a^¡*�4�>g!N&=*�465G*p1�;�&7-+>C<=$2(65G(+*�32rs<n571�16&7-{;�&�DC8�305G;wz�>H;R-�!^h�5G(6-v*�4?>U!N&[*�4657*.<n5G1�16&7-u&)�?#%&)1�¨*�$'>H(6!%l �$'|U&)(p*�4�$0!�5C!�!N8�<=1?*�$'>H(�hC*�4�&)rw*�&7!9*�&7-:@B>H;�*�4?&�&)�+$O!9*�&)(6#^&�>G@�!986#c4�!N16&7#%$05G32$"!757*�$'>H(�F+r;�&)<=>7|+$'(�D.&}5C#R4u4�$O-�-+&)(s8�(?$'*�$2(u*�8�;�(�h�5G(L-{#)573O#%8?3O5G*�$'(�D[4�>7z <I86#R4n&T&,&7#%*�*�4�$O!A;�&)<=>7|H5G3465C-u>C(v;�&)DC8?3O5G;p57(6-{&)�?#%&)1�*�$'>H(u165G*�*�&);�(6!%l[m�*�z�5C!w1�;�&}-/$O#%*�&7-s*�4L5G*w$¤@�5s-+865G3�;�>H8�*�&I&)�+¨$O!N*�&7-�h?5sT\ZBSg�CWoVOYGZ�PRQU_^_cZRde�CWXVOQUT:zM>C8�30-qF6&w@B>C8�(6-=F6&)*9z�&�&)(n*�4�&w(+8�<tF6&);�>7@�&)�?#%&)1?*�$'>H(n5G(L-f ;�&�DC8�305G;%k�(?>C(+z�>C;J-�!�*�4657*A&75H#c4n4�$0-�-/&)([8�(�$'*�!9$'DH(�$��,#�5G(+*�3'rq#%>C(+*�;�$'F�8�*�&7-t*�>�l

mo(w@X5C#%*�hC5�!9<n5G323C`?QGa�V'WXVOYGZ�#%>H;�;�&)3O57*�$'>H(�z�5C!�@B>C8�(6-,l���465G*�$0!%h7*�4�&M;�&)<[>G|H573C>G@L$'(6-/$2|/$0-/865734�$O-�-+&)(w8�(�$'*J!�*�&)(L-/&7-�*�>�5\&�&}#%*�F6>H*�4�(?>C(+z�>C;J-�!�5G(6-�&)�?#%&)1�*�$'>H(�z�>H;R-�!�*�>�5�!N$2<=$'305G;,-/&)DH;�&)&f x�3O578�* �+�u#G��3'&�3'3O57(6-�h�i)jHj � kJln��4�$O! �6(6-/$2(�Ds32&7-ux�3O5G8?*�57(6- �u#G��3'&)323O57(6-�*�>u#%>H(6#%3'8L-/&*�4657*A*�4�&)$';M(�&)*9z�>H;��n-+$O-=(�>C*�$2<=1�32&)<=&^(/*�5I-/86573�;�>H8�*�&Ul

��4?&I5G(6573'r?!N$O!�<=&)*�4?>+-/>C32>CDCr�z�5H!�#%>C(L!N$O!9*�&)(+*w57(6-s;�&75H!N>H(65GF�32&Uh�DC$2|U&)(s*�4�&)$';�5C!�!N8�<[1�¨*�$'>H(v>G@�4�>7z 5u-/86573�;�>H8�*�&=zM>C8�30-{F6&n$'<=1�32&)<I&)(U*�&7- � F?8�*�z�5C!�*�4L5G*I5C!�!N8�<[1�*�$2>C(v$2*R!N&�3¤@;�&75H!N>C(L5GF�32& $um�z�>H8�3O-n5G;�DC8�&p*�4657*A$2*�z�5H!�8�(?(�&7#%&7!�!�57;�$'32rt;�&7!N*�;�$0#%*�$2|U&Uh+5C!�*�4�&);�&�$O!�(�>I;�&757¨!N>C(~*�>uF\&�3'$'&�|U&.*�4657*.*�4�$0!�<=&)*�4?>+-{$O!w*�4�&EQUT+d � z�5)rE*�>u$'<[1�3'&)<I&)(+*�5u-+865G3�;�>C8�*�&=$'( 5#%>C(�(?&7#%*�$2>C(�$0!N*p5G;J#c4?$'*�&}#%*�8�;�&Uh�<I86#R4u3'&7!�!�*�465G*p*�4�$0!�a9`6Z�P)V �MPw(�&)*9z�>H;��uz�>H8�3O-u$'<[1�3'&)<[&%(+*$'*�$2(E!N86#R4E5t@X5C!N4?$'>C(�lt��(E5C-�-/$2*�$2>C(6573�1�;�>HF�3'&�< $O!�*�465G*�*�4�&);�&.$O!%h�5H!�@X57;p5C!wm��+(�>7zwh�(�>

���>Ej`aq1`a]'VXg EHDjgcVXDjGIs .%k<VXE<VX]aEHJhB EHGALp`aW Z\GI`'L\GIW)(nGIgHs%VXWYL�* b6+l]aGI]a]'VXWnL%McOoQ�RTQ�UIv

Page 76: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � �'����� � ��� � � �� � ����� � � ��� � �"!���# � � !���� � �

-/&)<=>H(6!N*�;R5G*�&7-n#)5C!9&w>G@�4�$0-�-/&)(n8�(?$'*R!�!N16&7#^$O5G32$"!)$2(�D�$2(n*�4�&w;�&�1�;�&7!9&)(+*R5G*�$'>H(�>7@M5=a�]/�ca7ZJW�>G@*�4�&�*�>C*J5G3�*�;R57$'(�$2(�D.!9&)* �U1657*�*�&�;�(=;�&)1�;�&}!N&)(+*R57*�$'>H(6!�57;�&�*9r+1�$O#�5G3'32r:@B>H8�(6-t*�>.F\&�-/$O!9*�;�$2F�8�*�&7->G|U&�;�573'3 f >C;�<=>U!9*%kM4�$O-�-+&)(s8�(?$'*R!^l���4�&.(?&)DU57*�$'|U&p>C8�*J#%>C<[&:>7@M*�4�&)$2;A*�&7!N*�z�5H!�*�4�&);�&%@B>C;�&8�(6!N8?;�1�;�$O!N$2(�D�l

��>Gz�&)30!N&UhU*�4?&)(�h�#^>C8�30-�5.-+865G3�;�>C8�*�&�F6&:$2<=1�32&)<t&�(/*�&)-�$2(n5.-/$O!9*�;�$'F�8�*�&7-t(�&�*NzM>C;�� $qm1�;�>H1\>g!N&�5�z�>C;��/$2(�DI5C!�!N8�<[1�*�$2>C(nz�4�$O#R4=$0!�<=>C;�&ADH&)(�&);J5G3�*�4L5G(n*�4657*A8L!N&7-=F+r=x�3O578�*�5G(L-�u#G��3'&)323O57(6- f i�jCj � kRh�57(6-{$O!^h�mAF6&)32$'&)|U&gh�<=>C;�&I!N8�$2*�&7-E*�>s*�4�&[#%>C(�(?&7#%*�$2>C(�$0!N*w1657;R5C-+$'DC<�l��4�& �.VOT�V �.] � _cZ � ]+VO_cZ��tZcT/W�@B>C;.*�4?&s&)�+$O!9*�&)(6#^&t>7@p5{-+865G3�;�>C8�*�&s$O!�*�465G*I;�&�DC8�305G;I5G(L-&)��#^&)1�*�$2>C(u1657*�*�&);�(6!�F6&[-/$O!9*�$'(?DC8�$0!N4657F�3'&.$2(E!N>C<[&.z�5)rUh�$'(u*�4�&t$2(/*�&);�(L5G3�;�&)1�;�&7!N&�(/*J5G*�$2>C(>G@6*�4�&�(�&�*NzM>C;���l�m�@6(�>w!986#R4�-+$O!N*�$'(6#^*�$'>H(�&)�+$O!9*R!^hG*�4�&)(�*�4�&);�&�#�5G(�(�>H*�F6&�-/8L5G3+<=&7#R465G(�$0!N<n!^h>C;�5�;�&)DC8�305G;�¨�&)�?#%&)1?*�$'>H(�-/865G3�;�>H8�*�&p>G@M57(/r�-/&}!�#%;�$'1�*�$'>C(�h�F\&}#)5G86!9&�*�4�&);�&w$0!�(�>=<=&757(6!�>G@-/$O!9*�$'(?DC8�$0!N4�$2(�Dn*�4�&I*9z�>sDH;�>H8�16!:>7@�165G*�*�&);�(6!�!986#R4{*�465G*�5G3'*�&);�(L5G*�$2|U&.<n5G1?1�$'(�Dg!w#)5G(vF6&5G1�1�32$'&7-�*�>w*�4�&)<�l�x�3O5G8?*�57(6-��u#G��3'&)323O57(6- f i)jCj � k�5C!�!98�<=&7-�*�465G*�*�4�$O!�-+$O!N*�$'(6#^*�$'>H(.z�>H8�3O-F\&p-/&�*�&7#%*J5GF�32&�57*�*�4�&�3'&)|U&)36>7@�4�$0-�-/&)([8�(�$'*J!%l �srI1�;�>H16>U!�573�$0!�*�4657*�>C(�&�!N4�>H8�3O-n3'>U>C�I@B>C;$'(+*�&);�(65G3�-/$0!N*�$'(6#%*�$'>H(6!�>C(E5I-/$ &,&);�&)(+*A32&)|U&)3o¡�$'(�*�4�&p`��CWBW9Z^_%TuQN¥��UP%WXVOY)�CWXVOQUT�a�*�4657*�;�&�DC8�305G;5G(6-n&)��#^&)1�*�$2>C(=8?(�$'*J!�&)3'$0#%$'*�>C(�*�4�&w4�$0-�-/&)(n8�(?$'*R!^l

mo(u&T&,&7#^*)h,x�305G8�*�5G(6- �u#G��3'&�3'3O57(6-l� ! f i)jHj � k�5H!�!98�<=1�*�$'>C(uz�5C!A*�465G*w;�&)DC8�305G;w57(6-s&)�+¨#%&)1�*�$'>C([z�>C;J-�!�z�>C8?3O-tF6&p-/$O!9*�$2(�DC8�$0!N4657F�3'&wF+rt|+$';�*�8�&�>G@�F\&�$'(�D.;�&)1�;�&}!N&)(+*�&7-.>C(�-/$ &,&);�&)(+*4�$O-�-+&)({8?(�$'*J!%h�5G(L-{*�4�&�;�&%@B>H;�&Iz�>C8?3O-{F6&n!9&)DC;�&)DU57*�&7-v$'(+*�>ua7Zo`?�U_��CWNZI§UV �tZcT�a�VOQUT�ap$'(E*�4�&4�$O-�-+&)(s8�(?$'*�!N1L5C#%&Ul1�sr�5C!�!N8�<[1�*�$2>C(n$O!�z�&757�U&);�$'(�*�4657*�573'3�z�>H;R-�!�#�5G(sF6&p;�&)1�;�&7!N&�(/*�&7->G|U&�;�*�4�&�!�5G<[&�!N&)*�>G@�-+$'<=&)(L!N$'>H(6!%hHF�8�*�<I86!9*�F6&�-/$0!N*�$'(�DH8�$O!9465GF�32&AF+r.*�4?&w!Nr?!N*�&)<n5G*�$O#)573'32r-/$ &,&);�&)(/*p16>U!N$2*�$2>C(6!.*�4�&�rv5H-/>C1�*Iz�$'*�4�$'(y*�4�>g!N&�-/$'<[&)(6!N$2>C(6!^lEx�305G8�*I57(6- �u#7��3'&)323O5G(L-l�K!f i)jHj � k�5C!�!N8�<=1?*�$'>H(n$O!�!N$2<=1�32rI5.!N16&7#%$05G3�#)5H!N&w>G@�*�4�$O!�<[>C;�&�DC&)(�&�;R5G3�@B>H;�<I8�3O57*�$2>C(�l

��!A57(u&)��57<=1�32&�>G@�!N8L#c4�5�;�&)1�;�&}!N&)(+*R57*�$'>H(65G3�-/$0!N*�$2(6#%*�$'>C(�h�>C(�&.<=$2DC4+* �6(L-s*�4657*�;�&)DH¨8�3O57;A1657*�*�&);�(6!�*�&)(6-n*�>n#^3'86!9*�&);�$'(�*�4�&p<=$O-�-+3'&�>7@�4?$O-�-/&�(s8�(�$2*�!9165C#^&Uh\z�4?$'3'&p&)�?#%&)1�*�$'>C(L!>+#)#%8�1+r~>C8�*J!N$O-+&s&7-/DH&7!=57(6-£#%>C;�(�&);J! f z�4�$O#R4�zM>C8�30-�#%>H;�;�&}!N16>C(6-£*�>E&)�?#%&)1�*�$'>H(6!�F6&)$2(�D&)(6#%>+-/&}-�z�$2*�4u&)�+*�;�&)<=&w|H5G3'8?&7!A>C(y*�4�&.4�$0-�-/&)(u8?(�$'*J!ckRl��A3'*�&);�(657*�$2|U&)3'rUh�>H(�&I<=$'DH4/* �6(6-*�4657*�573'36&)�?#%&)1�*�$'>H(6!�465)|U&�5w#%>C<[1\>H(�&)(+*�>G@�*�4�&�$';�;�&)1�;�&}!N&)(+*R57*�$'>H(t$2(.>C(�&�>C;M*9z�>w!9&)165G;J5G*�&-/$'<=&�(6!N$2>C(6!^h�z�4?$'3'&w;�&)DC8�305G;�1657*�*�&);�(6!�-/>.(�>H*A1L5G;�*�$O#%$2165G*�&w$'(n*�4�>g!N&p-/$2<=&)(6!9$'>C(L!%l

��4?$O!I#%>C(6#^&)1�*�$2>C( >G@p4�>7z 5v-/8L5G3�;�>C8?*�&s$0!�$2<=1�32&)<=&^(/*�&7-�$0!t#^>C<=1657*�$2F�3'&=z�$2*�4 *�4�&

Page 77: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� E ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

;�&7!98�3'*J!�>G@�-/$O!�!N>+#%$05G*�$2>C( !N*�86-/$2&7!�;�&)16>H;�*�&}-ª$2(£��465G1�*�&); E�l~m�@�*�4�&�-/$O!9*�$'(L#%*�$2>C(vF6&)*9z�&�&)(;�&)DH8�3O57;R!.5G(L-ª&���#%&�1�*�$2>C(6!�$'(ª5u-/865G3M;�>H8�*�&�#%>H(�(�&7#%*�$'>H(�$O!9*�(�&)*9zM>C;��E#^>C8�30-ª>H(�3'rEF6&=&)�+¨1�;�&7!�!N&7-n3'>+#)573'32r�$2(s*�&);�<n!�>7@�4�$0-�-/&)(�8�(�$'*J! f 5H!�x�3O578�*%� �u#G��32&)3'305G(6-�h,i)jHj � h�5H!�!N8?<=&7-\kJh*�4�&)(~>H(�&nz�>C8?3O-v&)�+1\&}#%*�*�465G*�QUT/d � *�4�&n3'&7!9$'>C(?$'(�D�*�&7#R4�(�$ ��8�&[>G@pb?VO§U§/Z^T�]+T�V'W._RZ��.QUY)�Cd#%>C8�30-v#)5786!N&�-/$0!�!N>+#^$O5G*�$'>H(6!%l �A>7z�&�|U&);)h�5C!�zM&=465)|U&n!9&)&)(v$2(���465G1?*�&); E?h�-/$O!�!N>+#%$05G*�$2>C(6!465)|U&�F6&)&)(�&)3'$0#%$'*�&7-t|+$O5tzM&)$'DH4/*�;�&)<[>G|H573oh�5H-�-/$2*�$'>H(u>G@M(�>H$O!N&gh\;�&7!�#)573'$2(�D=>G@�z�&)$2DC4+*R!%h,5G(L-<n5G(+rs>H*�4�&);p3'&7!9$'>H(�$'(�Dn*�&7#c4?(�$ �U8�&7!�*�4L5G*.571�1657;�&)(+*�32rE5G;�&q5GF�32&=*�> >KF�328�;\��*�4�&=(�&�*NzM>C;��l� !$'(+*�&);�(65G3,-/$0!N*�$2(6#%*�$'>C(IF6&)*9z�&)&�(t;�&)DC8�305G;J!�5G(L-q&���#%&�1�*�$2>C(6!^l�mo*�*�4�&);�&%@B>C;�&w!N&�&)<n!�32$'�U&)32r:*�465G**�4�&I-/$0!N*�$'(6#%*�$'>H(u$O!�&)(6#%>+-+&7-s$'(y5=<=>C;�&.#%>H<=1�3'&���h,-/$O!9*�;�$'F�8�*�&7-�@X5C!94�$'>H({*�465G(E&)(+|/$0!�57DC&7-F/rnx�305G8�*�57(6- �u#G��32&)3'305G(6- f i)jHj � kRl

��4?&n5C-/|H57(/*J5GDC&n>7@�<IrszM>C;��+$'(?Du5C!�!N8�<[1�*�$2>C(v$0!:*�4L5G*�$2*.-/>U&}!�(�>C*p1�;�&7!98�1�16>U!9&n*�4�&T��CWo]+_cZ�>7@�*�4�&w;�&)DH8�3O57;�¨B&)��#^&)1�*�$2>C(n-+$O!N*�$'(6#^*�$'>H(�h/>H(�3'r[*�4657*A*�4�&);�&�<t86!9*�F6&w>C(�&�@B>H;�5t-/8L5G3;�>C8?*�&�*�>�&)�/$0!N*�l�mo*�-/>U&7!�(?>C*�&)|U&�(�1�;�&7!N8�1?1\>g!N&�*�465G*M5G323/(?&)*9z�>C;���!�$'<[1�3'&)<I&)(U*,*�4�&�-/$O!9*�$'(L#%¨*�$'>H(.$'(.*�4�&�!�57<=&�z�5}r �U57(6-�$2(6-/&)&}-:*�4?&�$'<=1�32&)<I&)(/*�57*�$'>H(p#%>C8�30-.-/$ &,&);�z�$O-/&)32rp-/&)16&)(6-/$2(�D>C(s*�4�&w165G;�*�$0#%8�3O57;�*�;J5G$'(?$'(�D.1�;�>CDH;R5G<�h/(�&)*9zM>C;��q5G;R#R4�$2*�&7#%*�8�;�&�>C;�!N*J5G;�*�$'(?D=!9*R5G*�&Ul

��4?&I-/$O!�5C-/|H5G(+*R57DC&.>7@�!986#R4E5G(E5C!�!N8�<[1�*�$2>C(u$O!�*�4L5G*�$2*ADH$'|U&7!�(�>�#%3'&}5G;�$'(6-/$0#)5G*�$'>H(s>G@4�>7z�!N8L#c4y5s-/$0!N*�$'(6#%*�$'>H(E#%>C8�30-�F6&[-/&)*�&7#%*�&}-�lK�srE5G1?1�;�>g5C#R4v4�&);�&.$O!�*�>n86!9&=!9*R5G*�$O!9*�$O#�5G3|/$0!N86573'$"!}5G*�$2>C(�*�&7#R4�(�$ ��8�&}!�*�465G*p5G;�&I-/&7!9$'DC(?&7-s*�>n-+&)*�&7#^*�<=&757(�$'(�D7@B8�3�#%3286!N*�&);�$2(�D=>G@M1657*�¨*�&);�(6!�$'(.4?$'DC4?¨o-/$2<=&)(6!9$'>H(65G3?!N165H#%&7!^l �A(?&�-/>U&7!�(�>C*�(�&�&7-�*�>w�+(�>7z�$2(=5H-/|H5G(6#^&�z�465G*��+$'(6->G@�#%3'86!9*�&);�$'(�D.>H;�!N&)1L5G;R57*�$2>C(u&)�+$O!9*R!��+*�4�&p!9*R5G*�$O!9*�$O#�5G3�*�&7#R4�(�$ �U8�&7!M-/&)*�&7#%*�*�4L5G*�@B>C;�rU>C8�l

� ��� ��� ����+�� � 2 2 +� �� ����� ����+

���������������� "!#�$ "!&%��'%)(#�+*&�,%.-/ 10324�/�5%�(#�+26 1798#03-/%) "��!:2^h/ "%� ;2< 17>=:�?�)%@-A!&%B%)�DC�0;-A�) E��F$��!G�H�/�I%)(#�7>�J2�%� 17>=:����%@-A!&% f -A!:*LK:-�2� ;C/MNC��?!:C��,=#%.2O "!L!#�P%6QR����SL-A!:-/0"F#2� ;2^¡�%)(:-A%H�/�T%)(#�9UGVO§U§&WYX[Z\X#V1]

^�_#`Ja WR�/�R-b!#�,%�QR���)Sdc�ef%g ;2� 1!h%)(# 32i2�=:-�CY�$%)(j-/%H%�(#�$!#�P%6QR����Sk������7h2� 1!\%)�,��!:-/0l���,=#���A26�,!\%@-Am%) 1�?!:2i�A��=j-/%)%��,�)!j2%hl-?2H-/!n "!&%��,�)7>�o*& ;-A%)�'2�%)�,=n "!L%)(G�b7h-/=#=G 1!#�b���)�?7p%�(#�b 1!G=#8#%g0;-,FJ�,�g%)�%)(#�D��8#%�=#8#%H03-oFJ�P�,ct�LFL-?2)2�8#7>=#%� 1��!q ;2�%)(:-A%'-/!\Fq*&8:-A04����8#%��$798:26%�K:�9*&�,%��AC�%.-/K#0"� r\ ;-9-*& ;2�%) 1!jC�%) "��!$7s-�*&�RKt�P%6QR�,�,!b���,��8#03-/��-A!:*b�,u#CY�,=#%) "��!D=:-/%�%)�,��!:2< 1!$%�(#�, "�<(# ;*G*&�,!b8#!# "%�26=j-�C���)�,=#���A26�P!&%.-/%) "��!lc

v (G�i(# 3*#*&�,!b8G!# 1%R26=j-�C��gC,-A!kK:�+C���!jC��,=#%�8:-/0" "!,�A*D-�2R-/!hw>mx*& 17>�P!:26 "��!:-A0#2�=:-�C��ghyQ�(G�,�)�

Page 78: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � �'����� � ��� � � �� � ����� � � ��� � �"!���# � � !���� ���

w ;2k%�(#�n!\8#7kK:�,�9�/�D(# 3*#*&�,! 8G!# 1%.2k 1! %�(#�n!#�,%�Q��?�)S�� 2 f 26 "!#��0"��M$(G ;*#*&�P! 0;-,FJ�,�,c ��-?C (=:-/%�%)�,��!k%�(:-/%� ;2<=#���A26�P!&%��A* %��$%)(G��!#�,%�Q��?�)S$ 32<7h-/=#=:�A*$%��D- =:�? 1!\% "!b(# ;*G*&�,!98#!# 1%T26=:-?C�� � 1%@2�CY�J���@*\ 1!:-A%)�A2g-/���b*&�,%��,�)7 1!#�A*bK\F>%)(#�'rJ�ACY%)�����A�R-�CY%) 1r?-A%) 1�?!:2� 1%��P01 ;CY 1%@2���!q%)(#�'(# 3*#*&�,!8#!# 1%.2�c

�+2�-k2� 17>=#0"�i�Pu#-A7>=#01�gh&2�8#=#=:�J2��$%�(#�,�)�D-A�)�'%)(#���,�'(# ;*G*&�,!h8#!# "%@2 f U��Ch U #/h:-/!j* U��JM� 1!- !#�,%�QR���)S,h5-/!:* %)(#�9=#�)�o26�,!\%@-A%) 1�?! �/�O- =:-A%)%��,�)!�� C,-A8:26�A2'%)(#�b����0"01�AQ� 1!G� (G ;*#*&�P![8#!G 1%-�C�%� 1r?-/%� 1��!j2��

U� U�# U�?�� ? � � ? � E

�[�'CP-/!>=#0"��%�=:-A%)%��,�)!��� 1!>%�(#�H=:�J2� 1%) "��! f ?&c /h ?&c � h ?&c E\M� 1!>%�(#�H!#�P%6QR����Sl� 2 f �/m � M�(# 3*#*&�,!8#!# 1%g2�=:-�CY�Uh:-�2g26�,�P! "!��4 "��8#��� �\c��?c

h1

h

0.8

2

h3

0.7

0.4

A

�4 1�?8#�)� �&c���� v (#�b=:� 26 1%� 1�?![�A��=j-/%)%��,�)!��� 1! -��Amf*\ 17>�,!j26 1�?!:-/05(# 3*#*&�,!q8#!# 1% 26=:-?C��Jc v (#�-/u\�A2>C��?�)�)�o26=:��!:* %)� %)(#�n%�(#�)�,�q(# ;*G*&�,! 8G!# 1%.2 U�Hh U # -/!j* U�/hg-/!:*�� � 2 C��J���.*& 1!:-A%)�A2C������)�A2�=t�?!:* %��k%�(#�D-�C�%� 1r?-/%� 1�?! r?-A018#�A2��P01 ;CY 1%)�o* K\F>=:-A%)%)�P�)!�� ��!L%�(#�J2��'8#!# 1%.2�c

�L� 26%NC���!#!G�AC�%) "��!# 326%�7>�\*&�P0;2<(:-,rJ�UhJ�/�BC��?8#�@2��Uhy�x-A��7>�?�)�g=:-/%�%)�,��!:2 ` X��i(# ;*#*\�,!k8G!# 1%.2%h01�A-?*& 1!#� %)� *&�P!:26�n�ArJ�,��0;-/=G=# 1!#� C�0"8:26%��,�@2b�/�D=:�� "!&%.2k 1! (# "��(#mx*& "7>�,!:2� 1��!j-/0g(# ;*#*\�,! 8#!G 1%26=:-?C��Jc v (G ;25C���7>=G01�,u\ 1%fF�7s-/SJ�A2: 1%5*& ��hC�8G01%l%)�gr\ ;268j-/010"F'*&�,%��AC�%I26�,=:-A�@-A%) 1�?!:2<-A!:* =:-A%)%��,�)!:2 1! %�(#�h(# ;*G*&�,! 8G!# 1% 26=:-?C��Jc��J�?7>�h�/�'%�(#�L%��AC (G!# �J8#�A2De$8:26�qKt�P01�AQ C����A-/%�� ^ V � _�� V ��W��^ Z �K� `�� V W ^ �A�5%)(#�+(# ;*#*\�,!>8#!# "%R26=:-?C��Uh&7s-/ 1!\%@-A 1!# "!#�H%�(#�H 17 =t�?�)%.-/!\%�*\ ;26%� 1!:CY%) 1�?!:2�-/%R%)(#�C��J2�%��/��0"�J26 "!#�926�?7>�D*&�,%.-/ 10xc

Page 79: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ( ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

� � � � 2 � � � �K0 2\* � ����� � 2 ��� � *�= ! 6 0$* � * � � ! 6

v (#�b-A 17 �/�R%)(G��:�.26%'2� 1798#0;-A%) 1�?!h ;2�%)�hC��?!:*&8:CY%H-"> =# 10"��%g2�%)8:*&F�� �A��7kF =#�)�?=t� 26�A*n%)�oC (#m!# �J8#���5*&�,%��AC�%� 1!#�D-'*&8:-A0 �)�?8#%)�g 1! -$CY��!#!#�oC�%) "��!# 326%<!#�P%6QR����SbK&F9*&�P%)�AC�%� 1!#� - � W _ � W ^ WYX\] `�]fV �JX ` � �JV �'W � WYX a WRK:�,%�Q��,�,! �)�,�?8#0;-A�H-A!:*>�,u#CY�,=#%) "��!h=:-A%)%)�P�)!:2� "! %�(#�'(# ;*G*&�,!h8#!# "%g26=:-?C��Jcv (#�h26 "7k8G0;-/%� 1�?! *&�o2)C��� 1K:�A*[ "! %)(# 32$2��AC�%) "��! -A0;2��n=#�)�Ar\ ;*&�A2'-A! �?=#=:����%)8#!# "%�F %)� *& 32)C�8j2)226��7 �H�/��%�(#�'7>�,%�(#�\*&��0"���? ;C,-A0 ;2�268#�o2� 1!\rJ��01rJ�o* "! 8j26 1!G�k%�(# ;2�%��AC (G!# �J8#�Jc

v (G� �J8:-?26 1���,��8G0;-/�g7h-A=#=# 1!G�$%@-?26Sh%)(j-/%ge�C@(#� 26�H�����g%)(# 32�-/!:-A01FG26 32� ;2�%)(G� 7s-/=#=# "!#�b�/��T!G��01 326(9%)�,u\%<%��$2�=:�,�AC@(lc �H2<7>�P!&%� 1��!G�A* �A-A�)0" 1�,��h��<0;-/8G%�-A!:*��nC���01�,0"0;-A!:* f ����� �JM<%��@-/ "!#�A*-$C��?!#!#�AC�%� 1�?!# ;2�% !G�,%�Q�����Sb%)�D 17>=#0"�,79�,!&%l%�(# ;2�7h-/=G=# 1!#�?h�K#8#%��x-/ "01�A*b%)���:!:*>-D*&8:-/0d�)�?8#%)� 1!L%�(#�, "�H2�8#K:26� �y8#�P!&%+-/!:-A01FG26 32O�A��%�(#�$!G�,%�Q�����S c��i�P�)�Uh:e����,=#01 3C,-/%��'%)(#�, "�H2�%)8:*\FL%)� 26�P�$ �%)(#�DC�8#���)�,!\%�%��AC@(#!# �J8#�A2R-/��� 7 ���)� 268:C,CY�A2)2f��8#0fc

� %�(#�)�,�Pm 03-oFJ�P� ���P�A*y������Q�-A�@* !#�,%�Q��?�)S f 2��,� �4 1�?8#�)���\c �JM$QN-�2$8:2��A*[�����9%)(# 32b26 1798#03-/m%) 1�?!�h�C��?!:26 326%) "!#�L�A� �D?� "!#=#8#% f �?�@-A=#(#�,7>�?Mi8G!# 1%.2%h �D?)?L(# ;*G*&�,! 8#!G 1%@2^h�-/!:* � � ��8G%)=#8#%f =#(#�?!#�,7>�?M�8#!# "%@2�c v (#�9%)�.-/ "!# 1!#� 26�,%DC��?!:26 326%��A* �A�1#����� �<!#�?01 326( 7>��!#� 26F\0103-/K# 3C Q��?�@*#2f �<0;-A8#%1���nC���0"�,0103-/!:*,h ����� �JM@c

v (G�>!#�,%�Q��?�)SnQN-�2b-/0"01�\C,-A%)�A* �@-/!j*&��7 2�%@-A�)%) "!#�LQR�, 1�?(&%.2%h5 1!# "%) ;-A01 f!,�A*L%)�q�@-A!#���h8#!# "m�����)7 01F'K:�,%�Q��,�,!bm ?&c ?��D-/!:*���?&c@?��&c v (#�+-�CY%) 1r?-A%) 1�?! ��8G!:C�%) "��!b�����R-/0"0#(# 3*#*&�,! -/!:*b��8G%)=#8#%8#!# 1%.2OQN-�2�%)(#�D2�%@-/!j*#-/�.*n26 1�?7>�� 3*k��8#!:C�%� 1��!�h#Q� 1%)( -�C�%� 1r?-/%� 1�?!:2OK:�,%�QR�,�,! ?k-A!:* �?c �J%.-/!#m*#-/�.* K:-?C S\=#����=:-A�J-/%� 1�?! fc� 8G7>�,01(j-/�)%5�,%R-/0xc'h ���� )(yM�Q�-?2<8:26�A*9-�2�%)(#�g01�o-/�)!G 1!#�'-A01�?���) "%)(#7�hQ� 1%)( -O0"�A-/��!# 1!G�i�.-/%)���A� ?&c ?��Hh�=:-/%�%)�,��!b8#=d*#-/%�� f fc � c'h,%)(G��Q��P 1��(\%@2lQ��P�)��8#=d*#-/%��A*b-o��%��,�5%)(#�=#�)�A2��,!\%@-/%� 1�?! �A���A-?C (h%)�.-/ "!# 1!#�b=j-/%)%��,�)!�� -A0;26�9S\!#�AQ�!L-?2 ^ ]�� a U `/^ ]xV a Z _ � ` ]�W)MRh:-b7>��7 �,!#m%)8#7�r?-/0"8#�g�/� ?&c��/hG-/!:*>-'=:-/%�%)�,��!>CY�) 1%��,�) "��!9�/� ?&c ���,c v (#�H!#�P%6QR����S$Q�-?2 %��@-/ "!#�A* ���?� �D? ?)?�,=:�\C (:2^h:-/%�Q�(# 3C ( %) 17 �� 1%�-?C (G 1�,rJ�A*�� �\c � B C������)�ACY%)!#�A2�2 �?! %�(#�'%)�.-/ 1!G 1!#� 26�,% f -�C,C��?�@*& "!#�%)�b%)(G� =j-/%)%��,�)! C��) "%)�,�� 1�?!�h #� ��D(b=:-A%)%)�P�)!:2���8#%g�/� #����� kQR�,�)�DC��?�)���AC�%)0"Fb7h-/=G=t�o*tM@c

v (G��� n#>=:-A%)%��,�)!:2g!#��%DC��?�)�)�oC�%)0"F>7h-/=G=t�o*LK&Fh%)(G�b!#�,%�Q��?�)Sq-/%H%�(#�b�,!:*L�A�R%)�@-A 1!# "!#�Q��,���i�,uGC�0"8:*&�A*$���)�?7 ��8#��%)(#�P��-/!j-/01FG26 32�c!�<-A%)%��,�)!:2�%)(:-A%�-A�)�'7h-/=G=t�o* "!:C������)�ACY%)01F -/���H!#��%7h-/=#=:�A*bK\Fk%�(#�H!#�,%�QR���)Sb%��b-A=#=#�)�?=#�) 3-/%�� =:� 26 1%� 1�?!:2� 1!>%�(#�g(# ;*#*\�,!>8#!# "%�2�=:-�C�� f fc �Jc'h?%)(#�!#�,%�Q��?�)S *&�J�A2$!G��%"�:!:* -/! -/=#=G�)��=G�) ;-A%)�h 1!\%)�P�)7>�A*\ 1-A%)�b�,!jC��\*& 1!G� �����D%)(#� 26�h=:-A%)%)�P�)!:2@M#�

?6&<[ G G�gHgHJTg bPgH`aDHG�gH`aJ�W B7EjGALrDj[7gHJTB7s�[ J�B7DKDj[7`aEKDH[7GIEj`aE �/EHGIG DH[ G%$$]aJ�EjEcVXg�. GIW\Djg�.5dfJ�g�V>L(GIDcV^`_]aGALG�7(u ] V^WYVXDj`aJ�W v

Page 80: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � � �

%)(#�,�����������h-/! -A!:-/0"F#2� ;2$%)(j-/%b(#�?=t�o2 %��n8#!:C��ArJ�,�'%)(G� "!&%��,�)!j-/0R26%��)8:C�%�8#�)�h�A�H%�(#�>(# 3*#*&�,!8#!# 1%g2�=:-�CY�$2�(#��8G0;* !G��%+C���!:2� ;*&�P��%)(#�D-/%�F\=# ;CP-/0 =:� 26 1%� 1�?!# 1!#�9�/�B 1!jC������)�AC�%�=j-/%)%��,�)!j2�c

��%g%)(#�D�,!:* �A�R%)�@-A 1!# "!#��h:%)(G�$Q��P 1��(\%@2� 1!q%)(#�D!#�,%�Q��?�)ShQ��P�)�DC�0;-A7>=:�A*>%)�>%�(#�, "� �:!j-/0r�-A018#�o2%h#-A!:*>%)(#� #� ��G( QR���.*#2�C������)�ACY%)01Fb0"�A-/��!#�A*kK\F9%)(#�H!G�,%�Q�����SbQ��,���H=#���A26�,!\%)�o* %��b%)(#�!#�,%�Q��?�)S -/�J-A 1!lc v (G�$-?C�%) "r?-/%) "��!:2��,01 3C� 1%��A*$K\Fk%�(#�HQ��?�@*#2��?!h%)(#� �G? ?$(# 3*#*&�,! 8#!# 1%.2�Q��,���2)-,rJ�A*n%)� �j01�UhBC��)�A-A%) "!#�q- #� �D(�� �G? ?L7h-A%)�� 1uL�A�+-�C�%� 1r?-/%� 1�?!:2�c v (# ;2'7h-/%��) "uL=#���/r\ ;*\�A*%)(#�b�.-oQ *#-A%@-k����� -/!:-A01FG26 ;2 � �i�)�b%�(#�$���,��8#03-/�'-A!:*n�,u#CY�,=#%) "��!qQ����.*#2H2��,�����,�J-A%)�A*n 1!q%)(#�(# ;*#*\�,!h8#!# 1%g2�=:-�CY� $

+-/%)8G�@-/0"01FUh? 1%5Q���8G0;*bKt�� "!&���A-?26 1KG01� f -/!:*b8#!#�P!#01 "��(\%)�,!# "!#�&Md%)�D*& "�)�ACY%)01F+�,u#-A7> 1!G��-H�.-oQ=#01�?%4�A�:!#�A-A�)01F �)? ? ?gQ����.*#24 "!b- �D? ?Amf*\ 17>�,!j26 1�?!$(\F&=:�,�.26=:-?C��Jc �<rJ�,!$ E�#%�(# ;2lQ��P�)��=:�J2)2� 1K#0"�Uh-O7>�?�)�<Kj-�26 3C =#����K#0"�,7 QR��8#03* =#���A26�,!\%l 1%.26�,0E��� %)�+*&�,%��AC�%5-A!&F'*\ ;26%� 1!:CY%) 1�?!'Kt�P%6QR�,�,!'�)�P��8#03-/�-/!:*>�,uGC��,=#%� 1�?!>Q��?�@*#2^h ` ��� =#0"��%)%��A*k=:-A%)%��,�)!:2�Q��?8#0;*>(:-,rJ�H%��bK:� 03-/K:�,0"01�A*>-?2 > ���,��8#03-/�4�#���> �,uGC��,=#%� 1�?!<��%��H�,uG-/7> "!#�<Q�(#�,%�(#�,� f -A!:* (#�AQHMl%�(#�,FDC�0"8:26%��,�l%)�?���,%�(#�,�,c � -/K:�,0"01 1!G�i=:-A%)%��,�)!:2Q���8G0;*b�)���J8# 1���Uh� "!k%�8#�)!�h\-D26�,%��/�BCY�) 1%��,�) 3-O�����NC�0;-?2)2� ��F\ 1!#�HQR���.*#2�-?2 K:�,01�?!#�� "!#�$%��$�?!#�H2��,%���g%)(#�'��%�(#�,���:-/!:*q268:C@(qC��) "%)�,�� ;-$*\�k!#�?%�FJ�,%��,u\ ;2�% f -?2OQ� "010dKt� *& ;2�C�8:2�26�A*k��8#��%)(#�,�� "!h%)(#�!#�,u\%HC@(:-/=G%)�,�YM@c�����%�(n�/�R%)(G�A26�D=#�)�?K#01�,7s2OQR�,�)�D=:-/��%) ;-A010"FL-?*#*&���A2)2��A*LK:�,01�AQwh "!L%)(G�b8:26��/�RUGV W �)`���a UGV a@` �la�� Z ^ ]�W �$` X ` � � ^ V ^ �?!q-k2�8#K:26�P%i�A�<=:-A%)%��,�)!:2Yc

� ��� ��� � � + :� :� �'���4����� ���&� + � +��� 0��t���

�i 1�,�.-/�.C (# 3C,-/0GC�0"8:26%��,��-/!j-/01FG26 32 f �� � MI ;2�-'*&�A2)CY�) 1=G%) 1rJ�N26%.-/%) 326%� ;C,-A0t%��AC@(#!# �J8#�NC���7>7 ��!#0"F8:26�A* 1! %)(#� 26�\C� 3-/0N2)C� "�,!:C��A2H%��L*\ ;2)CY�/rJ�P� ���,0;-A%) "rJ�,01Fh(#�?7>���?�,!#�,�?8:2 �?�)��8G=:2 �A�+268#K����ACY%@2 1! ->0;-A�)���b=:�?=#8#0;-A%) "��!�h5-�2H7>�o-�268G�)�A*hK&Fq%)(#�, "�'2)CY���)�o2i��! -h26�,%H�A���?K:26�,��rJ�A* r?-A�) ;-AK#01�o2�ce�%+*& 326=#03-oFG2�%)(#�A2��bC�0"8:26%��,�@2�K\F �?�)�?8#=# 1!G� %����?�,%)(#�P�)h �?! -k%�Q���mx*& "7>�,!:2� 1��!j-/05*&�,!j*&���?�@-/7�h268#K����ACY%@2<%)(:-A%�(:-,rJ�H-'26 "7> 103-/� _G` ] ]�W � X �A�B2)C��?�)�A2<��! %)(#�g��K:2��,�)rJ�o*$r�-A�) 3-/K#0"�A2 f Q�(#�,���H2� 17>m 10;-A�) "%6FD ;2<7>�A-?268#���A*$8:2� 1!#�D-/!s-/�)KG 1%)�.-/��F9*& ;2�%@-/!jC��i7 �,%)�� ;CCh?268:C@( -�2!�<8:CY01 ;*\�A-/! *& ;2�%@-A!:C���M.c

�g 1�,�.-/�@C@(# 3C,-/0:CY018:2�%)�,�R-/!j-/01FG26 32 (:-?2�-/0326�bCY��7>�g%)�DKt�+Q� ;*&�,0"Fb8:26�o*>-�2�-A!h-/ 3*k 1!> "!&%��,�)m=#�)�,%� 1!#�9%)(G�$2�%)��8:C�%)8G�)�$�A�� 1!\%)�P�)!:-A0l�)�,=#���A26�P!&%.-/%) "��!:2� "!L!#�P8#�@-A04!#�P%6QR����S#2Yc �#���g�,u#-A7>=#0"�Uh�T0"7h-/! f ����� ?yM'8j26�A* �� ��%)�L�Pu#-A7> 1!#�D%)(#�9(# 3*#*&�,!#m�0;-,FJ�,�+�)�,=#���A26�P!&%.-/%) "��!:2H�A�+-s���AC�8#��m�)�,!\%<!#�,%�QR���)Sb%�(:-/%�0"�A-/��!#�A*926 17 =#01�R���@-A7>7h-A�@2 �?(#�O���?8#!:*b%)(:-A%��/W ��� ^ -A!:*qX �JZ&X ^ �����)7 �A**& ;2�%) 1!jC�%�C�0"8:26%��,�@2^h#-A!:*�h#Q� 1%�(# 1!h!#�?8#!:2^h ` X#V � ` ]�WR-/!:* V;X ` X#V � ` ]�W��?K����AC�%@2�CY018:2�%)�,���A*>26�P=#m

Page 81: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

-/�@-A%)�,0"FJc��� ��(:-?2b-/0;2��nK:�,�,! �,7 =#01�AFJ�A*h 1! !#�P%6QR����S -A!:-/0"F#2��A2 K\F ��8G0101 "!:-/�� ;- f �����/E&MRhi�?�)7h-A! -/!:* �J� ��!#�AQg26S\ f ���� � JMRh��H-/!j26��!�-/!:* ��8#�)� f ����� ?yMJh � � 26�,!\K:�,�)� f ���� � JM9-/!j*� 101�o2�-/!j* �g010" 10;- f ����� �JM@c

ef! - !#�P8#�@-A04!#�P%6QR����ShC���!\%)�Pu&%�h#%)(#�D%)�@-A 1!# "!#�9=:-/%�%)�,��!:2iCP-/!LK:� C���!:2� ;*&�P�)�A*h%)(#��>E268GK#m���AC�%@2��'h:%)(#�D(# ;*G*&�,!n8#!# "%@2H-A�)�b%�(#� > ��K:2��,�)rJ�A*hr?-/�) 3-/K#0"�A2T�2hl-/!j*L%)(#�b=:-A%)%��,�)!:2��l-�CY%) 1r?-A%) 1�?!:2��! %)(#�h(# 3*#*&�,! 8#!# 1%.2b-/���>%)(#�P 1� > 2)C��?�)�A2��4�?! %)(G�J26�hr?-/�� ;-AK#01�A2Yc �<-/%�%)�,��!:2b-/���LCY018:2�%)�,���A*-�C,C��?�@*& "!#�b%)�9%)(G�$2� 17> "0;-A�) 1%�FD�/��%�(#�, 1�R=:-/%�%)�,��!L�A��-?C�%) "r�-A%) "��!:2���!h%)(G� (G ;*#*&�P! 8G!# 1%.2�c

��0"8:26%��,��-A!:-/0"F#2� ;2R*&�J�A2 !G��%��)�PrJ�A-/0#�Pu&=#0" ;C� "%)0"F Q�(j-/%�%)(G�H 17>=:�?�)%@-A!&%RC,-A%)�,�?���� 1�A2� 1!9%)(#�*#-/%.->-/���Uh#K#8#%+-/!q�,u#-A7> 1!j-/%) "��!h�/�T%)(#�9] � _ W��A��%)�.-/ 1!G 1!#�9=:-/%�%)�,��!:2�%)(:-A%HC��?!:26%� 1%�8#%)�'�A-?C (C�018:2�%)�,�gCP-/!L�? 1rJ�D-/!n "!:*& 3C,-/%� 1��!q-?2O%��>Q�(#�,��� %�(#�$7s- �����g*& 326%� 1!:C�%� 1�?!:2�01 "�Jc�ef!q%)(#� 26%)8j*&FC� 1%��A* -/K:�ArJ�UhO���?�L�,uG-/7 =#01�Uh �T0"7h-/! f ����� ?yM>���?8#!:* %)(:-A%L%�(#�n7h- ���?� ���,=#���A26�,!\%@-A%) "��!:-A0*& ;2�%) 1!jC�%) "��!9Kt�P%6QR�,�,!9Q��?�@*#2�QN-�2 7s-�*&�g��!h%)(G�HK:-�2� ;2��/�T26F\!&%.-�C�%� ;CgC,-/%��,���?�)F �4!#�?8#!:2�-/!j*rJ�,�)K:2RC�018j26%)�P�)�A*h26�P=:-/�.-/%)�P01FJc

�LFh�?�J-/0B 1!L8j26 1!G� �� � Q�-?2i%)�h2��,�$ E�R-/!\FqC�01�o-/�+C�018:2�%)�,�.2��,7>�,�����A*> "!L%)(G�$ 1!\%)�P�)!:-A0�)�,=#���A26�P!&%.-/%) "��! �/�N7>��!#� 26F\0103-/K# 3C$Q����.*#2%hB-/!:*,h4 �O26�?h4Q�(#�,%�(#�,�'%)(G�J26� C�0"8:26%��,�@2H�)���:�AC�%��A*-/!b 1!\%)�P�)!:-A0#*& 326%� 1!:C�%� 1�?!$K:�,%�Q��,�P!$�)�P��8#03-/��-A!:*$�,uGC��,=#%� 1��!D=:-/%�%)�,��!:2�c� i�H=#���,r\ 1��8j2<C�018j26%)�P�-/!:-A01FG26 ;2g�/�R%)(#�D 1!\%)�,��!:-/05�)�P=#�)�A2��,!\%@-/%� 1�?!:2O�A�R%)(#�, "�i!G�,%�Q�����ShQ�-�2g8#!:*&�,��%@-ASJ�,!nK&F%�<0;-A8#%-/!:*�nC���01�,0"0;-A!:* f ����� �yM.c

� =#�.-�C�%� ;C,-A0l=#�)�?K#01�P7 Q� "%)(qC�018j26%)�P�����@-A=#(:2^ht(#�AQR�,rJ�,�)h\ ;2�%�(:-/%�%�(#�,F �J8# ;C@S\01FbK:�AC��?7>� 1010"�,�� "K#01�� E�<%��J�k7s-/!\Fb=:-/%�%)�,��!:2i-A�)�'=#0"��%)%��A* c � 2��,=:-A�@-/%��$=#����K#0"�,7 ;2�%)(j-/%)h#%��b 1!\%)�,��=#�)�P%%)(#�'CY018:2�%)�,�.2 1! %)�,��7h2<�/�B%)(#�H���,��8G0;-/� � �,uGC��,=G%) 1�?!h*& 326%) "!:C�%� 1��!�h&e<QR��8#03*s(j-orJ�+%)�$03-/K:�,0 ` � �%)�@-A 1!# "!#�n=:-A%)%)�P�)!:29-�2 > �)�,�?8#0;-A�\�<��� > �,uGC��,=#%� 1��! �'h ���?�bQ�(# ;C@( !#�n���P!#�,�@-A010"F -A���)�P�A*&m�8#=:��!C��) "%)�,�� ;- �Pu& 326% ���?���<!#�?01 326(hQ��?�@*#2 f -?2O7>�P!&%� 1��!G�A*k-AK:�/rJ�?M@c

� 26�?018#%� 1�?! %)�qKt�?%)( %�(#� -/K:�ArJ�>=#�)�?K#01�P7h2i ;2H%��nC�0"8:26%��,�H��!G01F - 2�8#K:2��,%$�A�g%)�@-A 1!# "!#�=:-/%�%)�,��!:2O%�(:-/%g(:-,rJ�'=#�)�Pr& "��8:2�01F>K:�,�,!h 3*&�,!\%) �j�A*>-�2g�)�,�?8#0;-A�����g�,u#CY�,=#%) "��!h 1!h%�(#�$0" 1%)�P�@-/m%)8#���Jc�e�C (#� 26�'%)�b8j26�'%)(#� 26�,%.2��/�B7>��!#� 26F\0103-/K# 3CO���,��8#03-/�g-A!:*>�,u#CY�,=#%) "��!>QR���.*#2�26=:�AC� �:�A*K&F g018:2�(#SJ� f ��� � �yMN-/!:* v -/�.-/K:-A!n-/!j* �nC ��01�,0"0;-/!j* f ���� � M �tK:��%�(q26�,%.2�-/�)�+Q� ;*&�,0"Fk8j26�A* 1!>%�(#�'%)�A2�%) 1!G�b-/!j*L-/!j-/01FG26 32 �A��C��?!#!#�ACY%) 1�?!# ;2�%�%)�,u\%)mx26=:�,�oC (97>�\*&�,032 � h#-/!j*L-/0"0 %�(#�HQ��?�@*#2 1!hK:��%)( 26�,%.2�-/=#=:�A-A�H 1! %)(#�'%)�.-/ "!# 1!#� 26�P%�8:26�A*>K\F �<0;-A8#%g-/!:*�nC���01�P010;-A!:* f �������yM � c

% Z(GIG ��u7unGIWYL\` 7 � dfJTg VhbPJTq1u7]aGIDjG�]a`aEHDj`_W stJ^d DH[ G k�JTgcL\Eov��� `_Dj[%DH[7GFq1`aW7JTg<G87YbPGIu7Dj`_JTW J^d $$]aB7EH[7mTJ - E�gjGIs�B ] V^g������Pv3&<[ GtDjgcVX`aW7`aW7shEjGID L\`'L�9n[7JXklG�%�GIg 9�`aWYbP]aBYL\G

Page 82: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � ���

���+%)(#� � n#[QR���@*G2$!#��%97h-/=G=t�o* CY���)���AC�%�01F K&F %�(#�h!#�,%�Q��?�)S -/%9%)(#�h�,!j* �A�'%)�.-/ "!#m 1!#�?h E �kQ��,���' 1!L%�(#�bCY��79K# 1!#�o*k01 326%��/� g018j26(#SJ� f ��� � �JMg-/!j* v -A�@-/Kj-/! -/!:*�nC���01�,0"0;-A!:*f ���� � M$�,uGC��,=G%) 1�?! Q��?�@*#2Yc v (#�o26�>�,uGC��,=G%) 1�?!:2 QR�,�)� �,u#CY018:*&�o* ������7 -A!:-/0"F#2� ;2 f -�2bQ��,���%)(#�, "��C��?�)���A26=:��!j*& 1!#�b���,��8G0;-/�gCY��!\%)�)�?0 QR���@*G2 �:26�P� �i=#=:�,!:*\ 1u � M@c v (# 32��,u#CY018:2� 1��! 01����% �n#�,u#CY�,=#%) "��!h-A!:*"E ? 7s-/%@C@(# "!#�$���,��8#03-/��QR���@*G2 � c

v (G� a�� Z ^ ]6W � 8#%) "01 "%6F � Q�-?2�-/=G=#01 "�A* %��b%)(#�g(# 3*#*&�,!>8G!# 1%R-�CY%) 1r?-A%) 1�?!:2 �A�<%�(#� � #$�)�P��8#03-/�-/!:*>�,uGC��,=#%� 1�?!kQR���@*G2�c v (#� �<8:C�0" ;*&�A-A!>*\ ;26%.-/!:CY�H7>�A-?268#���iQN-�2�8:2��A* c �4 "��8#��� �\ca#b26(G�/Qg2%)(#�+C�018j26%)�P�) 1!G� �A�5%)(#�+Q����.*#2%h\Q�(# ;C@( -/�)�+0;-/K:�,0"01�A*b-?2��)�,�?8#0;-A� f�� M<�?���,uGC��,=#%� 1�?! f�� M.c �H2 ;2�C�01�o-/�<���)�?7�%)(#� �:��8G�)�Uh � � 2�-/!j* � � 2 -A�)�9X ��]:26�,�?�)�,� -/%)�o*k 1!\%)�D26�P=:-/�.-/%)� C�018:2�%)�,�.2 �JK:��%�(C,-/%��,���?�) 1�o2�-/�)�'QR�,010d�)�,=#���A26�P!&%��A*k 1!q-A0105268GK CY018:2�%)�,�.2�c

� 7>�P%)(#�\*&�?01�?�� ;CP-/0l=#����K#0"�,7 Q� 1%�(qC�018:2�%)�,�� 1!#� ��8j26%+-k2�8#K:26�P%i�A��=:-/%�%)�,��!:2� ;2�%)(j-/%g%)(#�26%)��8:C�%�8#�)�g�ArJ�,�<%)(j-/%�2�8#K:2��,%�7h-,F$!#�?% 7s-/%@C@(b%)(G�H2�%)�)8jC�%)8#���i�ArJ�,�B%)(#�gQ�(#��0"�i=j-/%)%��,�)! 26�P%,cv �'%)�o26%<Q�(#�P%)(#�,�5%)(G ;24QN-�2<%)(#�gCP-�26�ghJe4-A0;2�� =:�,��������7>�A*$-+C�018:2�%)�,�5�ArJ�,��-A010 #����G($C��?�)���AC�%)0"F&m7h-/=#=:�A*LQR���.*#2 �5%)(# 32 CY018:2�%)�,�� 1!#�>=G�)�\*&8:CY�A*[-h2�%)�)8jC�%)8#���926 "7> 103-/�g%)�h%)(:-A%' 1! �4 "��8#�����\ca#f -/!j*k 1!:CY ;*&�,!\%@-A010"F'-/0326�J8# "%)�g26 "7> 103-/�5%)�D%)(#�gC�0"8:26%��,�R*& ;-A���.-/7� 1! ��8#0"01 1!j-/�) 3- f �����/E&M<%�(:-/%Q�-�25*&�,�� 1rJ�A*����)��7�%)(#�t �� v %@-A01SD*#-A%@-��'-A!#��%�(#�,�5!#�,%�Q��?�)SH%��@-/ "!#�A*H%)�g=#����!#�?8#!:C�� �T!G��01 326(Q����.*#2 M.c

�#�?�$-A![ "!:*& 3C,-/%� 1��!q�/�NQ�(:-/%'K:-?26 ;C9C�0"8:26%��,�) "!#������W ^ �\C,C�8#��h %)(G� ��8#0"0<2�=:�,010" 1!#� 2i�/�N%)(#��,u#CY�,=#%) "��!q-/!j* ���,��8#03-/�HQR���.*#2iQ��P�)�$=G01��%�%)�A*h 1!n%�(#�b2�-/7>� C�018:2�%)�,�+*& 3-/���.-/7uh: 1!j26%)�o-�*L�/�%)(#� � -/!:* � 0;-AK:�,0;2 f 2��,� �4 1�?8#�)� �&c �yM@c� i�DC�01�o-/�RC��) "%)�,�� 1�?!b�,7>�,�����A2^h/K#8G% "%R*&�J�A2�-A=#=:�A-/�%)(:-A% QR���.*#2�-/�)�gK:�, 1!G�$CY018:2�%)�,���A*$%)�?���,%�(#�,����!9%)(#��Kj-�26 32 �A� � � ] U ��� ��`�_ UGV a 26 "7> 103-/�� 1%�FUh�%�(:-/% ;2%h#�?!h%)(#�, "�g26=:�,0"01 1!G�#c�ef!q26��7 �$CP-�26�o2�%)(#�DC�0"8:26%��,�@2�2��,�,7 %��bKt� *&�,%��,�)7> "!#�A*bK&F %)(#� �:�.26%01�,%�%)�,�.2��/��%�(#�'Q����.* f �Jc �Gc'h&%�(#�bCY018:2�%)�,�� 1!#�b�A�<=9���� � <=9���� � <������h-A!:*"<=9�� � MJh:-/!:*h 1!��%)(G�,�gC,-�2��A2�K&F9%)(#�'rJ�AQ��P0 f�� 9 � -/!:* ;-9 ��� ����� � �>-A!:*���� ;��#M@c

ef%g ;2gC�01�o-/�)h#(G�/QR�,rJ�,��h#%)(:-A%'C�018j26%)�P�) 1!G�b ;2DX ��]<*&�?!#�$�?!n%)(#�DK:-�2� ;2i�A��=#(#�?!#�,7> 3C'26 17 1m0;-/�� 1%�F ��26 "7> 103-/�)0"F&mx26=:�,0"01�A*bQ��?�@*#2H%�(:-/%'-A�)�b=#����!#�?8#!:C��o* y8# "%)� *& &d�,���,!&%�01FhCP-/!nK:�$����8#!j*

Dj[7G$k�JTgcL ����� � 9TEHJFDH[YV^D<k�JTgcLpk V^E<EHB�( EHDH`aDjB7DHGAL `_W EHDHGoV�L�v�6&<[ GIgHG�V^gHG�qpJ�gjG gHG�s�B7]'VXgjE Dj[YVXW G�7 biGIu7DH`aJTW7E;(nGAbIV^B7EHG $$]aB7EH[ m�J$McOoQ� TQ�UnVXWYL5&�V^gcV�(nVXW�V^WYL5* b6+l]aGI]a]'VXWYL

MPOAQTR� �UCEHJTq1GIDj`aq1GIE�EjuYGobP`"!YGAL � � # ��$ ����! bPJ�gjgHGIEjuYJTWYL\`aW7spgHGIsTB7]'VXgHE dfJ�glDH[ G EcV^q1G�G�7 biGIu7DH`aJTW klJ�gPL\EAv% � u7gHJTs�gcV^q dfJ�gKbP]aB7EHDjGIgH`aW7s [7`'L7L\G�W B7W7`aD VTbPDH`"%�V^DH`aJ�W7E/VXWYL u7gHJ7L\BYbi`_W s s�gPVXu7[7`'bIV^]tJTB7DHu B7D �&!YgHEjD

L(G�%�GI]aJTuYGAL ().('lJ�EH[ `_gjJ *%`/.\VXDcV5VXWYL bPB7gjgHGIW\Dj] . q V^`aW4DPVX`aW7GAL (). �eWYL\gHGoVXE>Z\DHJT] bjmTG M"GIq V^`_]*) EHDjJ�]"+bjmTG-,eEHunGIGAbj[ v EHgj` v bPJTq U�v &<[7GKu gHJ�sTgcV^q `aE V�%�VX`a]'V�(7]aG"().V^W7J�W).\q1JTB7EhdfDju d"gHJ�q dfDHu v `'bPEj` v (nGIgjm�GI]aG6.\v GAL\B;9. u7B�( . VX` . bi]_B EHDHG�g*+HS7v0/7v DcV^gAv01 v

Page 83: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

( ? ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

-20 0 20 40 60 80 100 1200

20

40

60

80

R X X X

X R R R X

R X R R

X X X R X

R R X R X

R X X X R R R R

R R X R X

R X X R R

X R R X R R X

X R X R X

X R X R R

R R X R R

X X R X R R X R R

�4 1�?8#�)� �\ca# � � C�018j26%)�P��*\ ;-/�?�@-A7 �/�B%)(#�+ 1!\%)�,��!:-/0:�)�P=#�)�A2��,!\%@-/%� 1�?!:2 �A�5�)�,�?8#0;-A�g-/!:*>�,uGC��,=#m%) 1�?!kQR���.*#2 "!��<0;-A8#%�-A!:* � C���0"�,0103-/!:*�� 2 f ����� �JM�!#�,%�Q��?�)S9-/%�%�(#�'C��?!:C�018j26 1�?!k�A�l%��@-/ "!# 1!G�#c�[�?�@*#2�(:-,rJ�HK:�,�,!h0;-AK:�,010"�A*h-�2��)�,�?8#0;-A�@2 f�� M��?���,u#CY�,=#%) "��!:2 f � M.c

Page 84: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � (��

-20 0 20 40 60 80 100 1200

20

40

60

80

wore were

worm word

work puff buff

posh push

must most

bust bus

bush bull pull

port post

heat dean deaf

breed bread

deed dread dead

head deal

beam dream wake

fade page

phase bath both

meld mild

doll wilt will

wild with

spool spook

big mode move

bowl sweet sweat probe prove

rouse wax wash ripe grape

write pink pint

dots got

choose plow

pump give

main pitch

gross class

slam

�4 1�?8#�)� �\c � � � C�018j26%)�P��*\ ;-/�?�@-A7 �/�B%)(#�+ 1!\%)�,��!:-/0:�)�P=#�)�A2��,!\%@-/%� 1�?!:2 �A�5�)�,�?8#0;-A�g-/!:*>�,uGC��,=#m%) 1�?!kQR���.*#2 "!��<0;-A8#%�-A!:* � C���0"�,0103-/!:*�� 2 f ����� �JM�!#�,%�Q��?�)S9-/%�%�(#�'C��?!:C�018j26 1�?!k�A�l%��@-/ "!# 1!G�#cv (#�D26=:�,010" 1!#�b�A�<�o-�C@( QR���.* ;2�2�(#�AQ�!lc

Page 85: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

(n# ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

C�018:2�%)�,���A* %����?�,%)(#�P�H 1!q%)(#�9*&�P!:*&���?�@-A7nc �#���+�,u#-A7>=#0"�Uh#%)(#�D=:-/ "�@2�6 � �)� -/!:* 6 � � hl-/!j*� �� � -A!:* � �� � c v (#�A26�>���?8#�bQ��?�@*#29-/���h-/0"0�=#�)�?!#��8#!jC��A* C������)�ACY%)01F K\F[%�(#�h!#�,%�Q��?�)S,hQ�(# ;C@(>7>�A-A!:2 %�(:-/%g%)(G� %��@-A!:2����?�)7h-A%) 1�?!h%)(:-A%gC������)�AC�%�01F 26�,=j-/�@-A%)�A2�%�(#�,7 �?!h%)(#�'��8G%)=#8#%26=:-?C��b7k8j26%�%@-ASJ�b=#0;-?C��$ "!n%)(#�DQ��, "��(\%@2iK:�,%�QR�,�,!L%�(#�$(G ;*#*&�P! -/!:*L�?8#%)=#8G% 03-,FJ�,�@2Yc v (#�C�018:2�%)�,�+-/!j-/01FG26 32H=t�P�6������7>�A*hK&F ��8#010" 1!:-A�) ;- f �����/E&MH�?![%�(#����� v %@-A01S *#-/%.- =#���\*&8:C��A* -2601 "��(\%)0"F>*& '&d�,�)�,!\%�*\�,!:*&�?���@-A7 K#8#%+26 17 10;-A�RC���!:CY018:2� 1��!j2�c

� %�(#������8#�?( -A!:-/0"F#2� ;2H�/�R%�(#�9C�018j26%)�P�'*& ;-A���.-/7 32iK:�,FJ��!j*L%)(#�92�C���=:�9�/��%�(# ;2g%)(#�A2� ;2 �268��sC��>%�� 2)-,F %)(j-/%)hR-/%901�o-�26%D��! %)(#�>Kj-�26 32 �A�H%�(#�h=#�)�o26�,!\%bC�0"8:26%��,�b-A!:-/0"F#2� ;2^h %�(#�,�)� ;2!#�b�,r\ ;*&�,!jC��H%)(j-/%�%)(G� ���,��8G0;-/��m �Pu#C��P=#%) "��!h*& 326%� 1!:C�%� 1�?!> ;2�%�(#�'7h- �����N*& ;2�%) "!:C�%) "��!>8j26�A*h%)����)� -/!# f!,�'%)(#�'(# 3*#*&�,!h8#!G 1%g26=j-�C��Jc

� 9 <=9��/; �v (#� -/K:�ArJ�n-A!:-/0"F#2� ;2kQN-�2>*& "�)�ACY%)�A* %)�AQ�-A�@*#2>*\ ;2)CY�/rJ�P�) 1!G�n �'%�(#�n!#�,%�Q��?�)S (:-?* 17>=#0"�,m7>�,!\%)�A*h-/! -/�@C@(# "%)�AC�%�8#�)� C���!\�����)7 1!#�>%��h%)(#� �&W XtW �)` � *&8:-/0�����8#%��k%�(#�,����F �l%�(:-/%' ;2^hl��!#� 1!hQ�(# ;C@(>���,��8#03-/�+-/!:*>�,uGC��,=G%) 1�?!h=:-/%�%)�,��!:2�-/���$7h-A=#=:�A*k8:2� 1!#� *& &d�,���,!\%�7>�AC@(:-A!# ;2�7h2�c

�g�/QR�,rJ�,��h -h*& '& �P�)�,!\%'-/=G=#�)� -�C@( C��?8#0;*LK:� -/����8#�A*L�����'�?![%�(#�bK:-�2� ;2H�/�N%)(#� ^�_ W a V � a%6F\=:�i�A�57h-/=G=# 1!#�'%�(#�H!#�,%�QR���)Sb(j-�2 0"�A-/��!#�A*b%)�b "7>=#01�P7k�Y!&% � �)�o-�*& "!#�$%��,u&%R-A01��8j* c$� (# 10"�%)(#�����P!#�,�@-A0 > ��8#01�,m��)�?%)� �,%�(#�,�?�)F f �Jc �Gc'h �< 1!#SJ�P�)h��������AM526%.-/%)�o2 %�(:-/%5�)�,�?8#0;-A�@25-/!:*'�,uGC��,=#%� 1��!j2-/�)�b7s-/=#=:�A*hK&Fq*& '& �P�)�,!\%i7 �AC (j-/!# 3267h2^h&%)(G�9*&8:-/0B�)��8G%)�$%�(#�,�?�)FL�A� � W ` �JV;X�� f ����01%�(#�A-A�)%�,%5-/0xc'h �������yM5=:�J2�%)8#03-/%)�o2<-Or?-A�) ;-A%) "��!$�?!b%)(:-A%4Kj-�26 3CT���?�)798#0;-A%) 1�?!� "%526%@-A%)�A25%)(:-A%4���,��8#03-/�.2%h-�2 QR�,010T-�2H�,uGC��,=#%� 1��!j2%h5C,-/! Kt�97h-A=#=:�A*Lr& 3->%)(#� > ����%)� � 7 �AC (j-/!# 3267%� 1! %)(# 32'C,-�2��Uhl%)(#�01�,u\ ;C��?!lc

ef%5 ;2 =#���A268G7h-/K#0"Fi�����5%)(G ;2l�)�A-?26��!b%�(:-/%BQ�(#�,! �<03-/8#%B-/!:* � C ��01�,0"0;-/!j* f ����� �JM501�A2� 1��!G�A*%)(#�, "�4!G�,%�Q�����S$%��'*&�,%��AC�%5�,r& 3*&�,!:CY� �����T-H*&8:-A0t����8#%��Uh�%�(#�,FDC���7 =:-/���A* %�(#��!#�,%�Q��?�)S�� 24=:�,��m�����)7s-/!:C��g��!h�,uGC��,=G%) 1�?!:2�-/!:* X �JX � � � � ^ "!:26%��A-�*>�/�5�?!h�,u#CY�,=#%) "��!:2�-A!:*>�)�,�?8#0;-A�@2�c��i�?!#mQ����.*#2%h\K:�AC,-/8j26�H%�(#�,F9(:-,rJ�i!#�?%�K:�,�,!h2��,�,!9K&F9%)(#�+!#�,%�Q��?�)S9*&8#�� 1!#�D%)�.-/ 1!G 1!#�?h#C,-A!#!#��%�K:�26%)�?�)�A*b 1!9%)(G�i0"�,u& 3C���!9-A!:*k(#�P!:C�� �bZ ^ ]#Kt�+7h-/=#=:�A*$r\ ;-H%�(#�i��8#01�g2�F#2�%)�,7 f �I��!#�g�,u\ ;26%.2 M.cex�d%�(#� �<03-/8#%R-/!j* � C���0"�,0103-/!:* f ����� �JM<!#�P%6QR����Sb 17>=#0"�,79��!\%)�A*'-'*&8:-A0:�)��8G%)�+-/�@C@(# "%)�AC�%�8#�)������b�)�o-�*& "!#�n-?2b26=:�AC� �:�A*[K\F ���?01%�(#�A-/��%)h�%)(#�P! *& ;2�26�\C� 3-/%� 1��!j2$Kt�P%6QR�,�,! �Pu#C��P=#%) "��!:2'-/!j*

� W �JZ �E`��)^ QR��8#03*sK:� *& ��sC�8#0"%�%)�b�P01 ;CY 1%)hJK:�AC,-A8:26�D�,rJ�,!> E�<0"�A26 "��!:2�7s-/!:-A���A*>%)� C��?7>=#01�P%)�,0"F

Page 86: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � ( �

*&�A26%��)�AF>%�(#�H�)8G01�D26FG26%��,7uhJK:��%)(q%�F&=:�A2��A�<=:-A%)%��,�)!:2�CY��8#03* 2�%) "010 K:�DC��?�)�)�oC�%)0"Fk7h-A=#=:�A*kK\F%)(#������%)�g2�8#K:2�F#2�%)�,7nc v (#�P�)�����?�)�Uh�!G��!\Q����.*#2 QR�,�)�R8:26�o* �JK#8#%<!#�D*& 32)2��\C� ;-A%) 1�?!kQN-�24����8G!:* c

e �B%)(#� _ � W ^ WYX&]l�)�P=#01 3C,-/%� 1��!h�A��%)(#� �<0;-A8#%+-/!:* � C���01�,0"0;-A!:* f �������yM�!#�P%6QR����S>(:-�*h 17>m=#01�,7 �,!&%��A*h-L*&8j-/0�����8#%��h-/�.C (G 1%)�oC�%)8#��� ���?�$�)�o-�*& "!#� f �- 0;- ���?01%)(G�A-/��%�MRh5%)(#�P![�?!#�hC��?8#0;*-/�)�?8#�9%)(:-A% "%H7> "��(\%H2� 17> "0;-/��01F>K:� W `/^ V W � %��q*&�,%)�oC�%'->�)�,=G�)�A2��,!&%.-/%� 1��!j-/0�*& '&d�,�)�,!jC��bK:�,m%6QR�,�,!9�,uGC��,=#%� 1��!j2 -A!:*>!#��!\Q��?�@*#2^h&%�(:-/!h 1%�QR��8#03*sK:�HK:�,%�QR�,�,!9�,u#CY�,=#%) "��!:2�-A!:*>�)�,�?8#0;-A�@2f -/0"%)(#�?8#��( �,uGC��,=G%) 1�?!:2$-A!:* �)�,�?8#0;-A�@2b2�(#��8#03* 26%) "010RKt�s*& ;2�C��,�)!G 1K#0"�k "! %)(#�P 1�$���,=#���A26�,!\%@-Am%) 1�?!:2 M.c

v �9C,-A%)�,�<�����R%)(# 32 =:�J2�26 "K# 10" 1%�FUhJ%)(#� C�018:2�%)�,�R-A!:-/0"F#2� ;2 QN-�2RC,-/���) 1�o*k��8#%N-/� -/ 1!�h#C��?7>=:-/��m 1!#�9!#��!\Q��?�@*#2^ht���,��8G0;-/�.2i-A!:*L�,uGC��,=#%� 1�?!:2�cRe ��-9*&8:-A04����8#%��$ ;2� 17 =#01�,79�,!\%)�P*�hJ��!#�DQ��?8#0;*�,u&=:�ACY%�%)� �:!:*h-9*& ;2�%) "!:C�%) "��!h7h-?*&�HK:�,%�Q��,�P!>�,uGC��,=#%� 1��!s-/!:*h!#��!\Q��?�@*#2Yc

v (G��!#��!\Q��?�@*#2�C@(#�J2��,!bQ��,����%�(#�g2)-A7>��8#%� 10" "!,�A*HK\F �<0;-A8#%�-A!:* � C ��01�,0"0;-/!j* f �������yM5 1!%)(#�H%��A26%� 1!#�D�/�B%)(#�P 1��!G�,%�Q�����S c �<0;-/8G%g-/!:* � C���0"�,0103-/!:* f ����� �JM�*\�b!#��%�0" ;26%R%)(#�o26�HQR���@*G2%h26�>%�(#�,Fh%)�J�>(j-orJ�DK:�,�,!L���,=#���\*&8:C��A*L "!��i=G=t�P!:*& 1u ���,c v (G�$!#�?!&QR���@*G2iQ��,���$=#���A26�P!&%��A*%)�H%�(#��!#�,%�Q��?�)S,hJ-/!j* "%<Q�-?2 ����8#!j* %�(:-/% ���H�A� %�(#��E �H!#�?!&QR���.*#2<Q��,����7h-/=#=:�A*DC������)�ACY%)01Ff Q� 1%�(b�)�A2�=:�AC�%<%�� %�(#��%@-A�)�?�,%�=#�)�?!&8#!jC� ;-A%) 1�?!:24=#���Ar& 3*&�A*$K\F �<0;-A8#%�� � C���01�,0"0;-A!:*tMdK&FD%)(#�%)�@-A 1!#�o*L!#�,%�Q��?�)Sdc �#���H%�(#�b�)�o-�26�?!:2H!#��%��A*n-/K:�ArJ�Uh �?!#01Fq%)(#�o26� ���>!#��!\Q��?�@*#2HQ��P�)�$8j26�A* 1!h%)(#�'=#���A26�P!&%NC�018:2�%)�,�g-A!:-/0"F#2� ;2Yc

v (G���)�A2�8#01%<�A�d%)(#�gC�0"8:26%��,�B-/!:-A01FG26 ;25��!9�)�,�?8#0;-A�@2%hJ�,uGC��,=G%) 1�?!:25-/!:*$!#�?!&QR���.*#2< ;2<2�(#�AQ�! 1! �4 1�?8#�)� �&c E#c��TuGC��,=G%) 1�?!:2'-/!:* ���,��8#03-/�'Q��?�@*#2D-/���>0;-AKt�P0101�o* Q� "%)( � � 2D-/!:* � � 2%h5-/!j*!#��!\Q��?�@*#2iQ� "%)( w � 2�c v (#�bKj-�26 3C$2�%)�)8jC�%)8#���b�/��%�(#�9C�0"8:26%��,�� 1! �4 "��8#����\ca#b ;2i���,=#01 3C,-/%��A*�hK#8#%b%)(G�L*\�,!:*&�?���@-A7 ;2b*&�,!j26�,�Pc v (#�q26=:�,010" 1!#� 2$�/� 26�?7>�>�/� %)(#�hQ��?�@*#2b-A�)�q26(G�/Q�! 1!�4 1�?8#�)� �\c ���<-A!:*$-A�J-/ "!'Q����.*#25-/=#=:�A-A�4%���Kt�RC�0"8:26%��,�)�o*i��!'%)(G� Kj-�26 32 �/�G%)(#�P 1� �?�)%�(#���?�@-/=G(&FJcv (#�,�)�+ ;2 !G�$ 1!j*& ;C,-A%) "��!>%�(:-/%�%�(#�i(G ;*#*&�P!>8#!# "%�26=j-�C��H "7>=#0"�,7>�Y!&%.24-A!&F>���,=#���A26�,!\%@-A%) "��!:-A0*& ;2�%) 1!jC�%) "��!>K:�,%�Q��P�,!h�)�,�?8#0;-A�@2%h#�Pu#C��P=#%) "��!:2^h � � !#��!\Q��?�@*#2Yc

� * .hDH[YV^W7m\E�DHJ�$V�%\` L� ]'VXB7DCdfJTg<q VXm\`aW7s$DH[ `_E<EjGID�J^d W7JTW\k�JTgcL\E�V�%�V^`_]'V (7]aG<DHJhq1GTv�� � klJ�gPL\E<[YV�%TG�(nGIGIW:gHGIu7gjGIEHG�W4DjGAL/VXE�VFunGIgH`aJ7L:M�0'v/- U3`aW�� `as�B7gjG /7v0/ DjJhgHGAL(BYbPGtbP]aB7DjDHGIgov

Page 87: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

( E ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

-20 0 20 40 60 80 100 120 1400

20

40

60

80

100

120

N R N X X X

N N X N N X N X X

R N X N R

X N X N N

X R N X N R X

N N N X N R

N X R X

X X R R R R R X N R

X R X N X

N R R R X

R R X R X

R R N N R

R R R X R N

R N N X N N X N N R N X

X R R R R X

R R N N X R R N N

N R R R N N

�4 1�?8#�)� �&c E ��� C�018j26%)�P�9*& ;-A���@-A7 �A�'%)(#�q 1!\%)�,��!:-/0����,=#���A26�,!\%@-A%) "��!:2$�A�$���,��8G0;-/��h��,uGC��,=#m%) 1�?!q-/!:*h!#��!\Q��?�@*#2i "!%�T03-/8#%+-/!j* � C���0"�,0103-/!:* � 2 f ����� �JM�!#�,%�Q��?�)Sh-A%i%�(#�DC���!jC�018:2� 1�?!L�/�%)�@-A 1!# "!#�#c��[�?�@*#2'(:-,rJ�bK:�,�,! 0;-/K:�,0"01�A* -�2H���,��8#03-/�.2 f�� MJh �Pu#C��P=#%) "��!:2 f � M+���'!#��!\Q��?�@*#2f wLM.c

Page 88: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � (��

-20 0 20 40 60 80 100 120 1400

20

40

60

80

100

120

porm . bork . worm word tord bool . nowl . doll . bull . spool . post . posh . nouse . mose bove . mode . choose . probe . rone bood boad plow reat heat deak deaf . dread dead head deal . dream beam . bread lere wore were meld . dase . tays . page must . bus bus bush . both puff buff nall tew . wax . will wild . mand main nad . wash choe . give meaf lear big . gross spook . grape write sweet sweat got dots dat phint pint . . natch bant sut . class slam . dramp

�4 1�?8#�)� �&c ����� C�018j26%)�P�9*& ;-A���@-A7 �A�'%)(#�q 1!\%)�,��!:-/0����,=#���A26�,!\%@-A%) "��!:2$�A�$���,��8G0;-/��h��,uGC��,=#m%) 1�?!q-/!:*h!#��!\Q��?�@*#2i "!%�T03-/8#%+-/!j* � C���0"�,0103-/!:* � 2 f ����� �JM�!#�,%�Q��?�)Sh-A%i%�(#�DC���!jC�018:2� 1�?!L�/�%)�@-A 1!# "!#�#c v (G�$2�=:�,010" 1!#�b�A���A-�C@(>QR���@*h ;2�2�(#�AQ�!lc

Page 89: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

( ( ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

� ��� ��� � �@H�<�' '��� ���� ����+ �� � � +��� 0 �:���

v (#�bC�0"8:26%��,�+-/!:-A01FG26 ;2�%)�oC (#!G *J8#�Uh#Q�(# "01�'8:26�Y��8#0<-?2H->*& "7>�,!:2� 1�?!>�)�A*\8:C�%) "��!q%)�J��0Xh ;2�01 "7>m 1%)�o*$ 1!9 1%@2�-A=#=#01 3C,-/KG 101 "%�F %��$03-/�)�?�H*G-/%@-D26�,%.2�c!��018:2�%)�,�.2T�A�50;-A�)���+26�P%@2�-/���'*& ��sC�8#0"%4%��$���A-�*-/!:*k "!&%��,�)=G�)�,%R26�P!:26 "K#01FJc � ���,0;-A%)�A*b=#����K#0"�,7� ;2<%)(G�H0;-?C Sb�A�5 1!&���?�)7h-A%) 1�?!b%)(:-A%g268:C@( C�018:2�m%)�,�D*& 3-/���.-/7h2'=#�)�Ar\ ;*&� �$%)(#�9 1!\%)�P�)=#���,%@-A%) 1�?![�A�HQ�(j-/% f �)�A-A0��?�$(\F&=:��%�(#�,%� ;C,-A0 Mgr?-/�) 3-/K#0"�A28#!:*&�,��01 "� %�(#�gC�0"8:26%��,�@2l ;2l8#!:*&�P�@C��?!:26%��@-/ "!#�A* c � %�(# 1�.*$=#�)�?K#01�,7� 32 %�(:-/%�CY018:2�%)�,�� 1!#�g ;24%�F\=# 1mC,-/0"01F'01 "7> 1%��A*H%)�'*& 326=#03-,F#24 "!b%�Q��D*& 17 �,!:26 "��!:2^h/Q�(G ;C@($Q� 10"0:C��?!:C��A-A0# 17>=:�?�)%@-A!&%B26%��)8:CY%)8#�.-/0 1!&���?�)7h-A%) 1�?!$ "!b 1!\%)�) "!:26 3C,-/0"01FH(G 1��(Gmf*& "7>�,!:2� 1�?!:-/0G*#-/%.-&c ��8#0"01 "!:-/�� ;-g-/0;2��'�@-/ 326�A*$%�(#����K����oC�m%) 1�?!>%)(j-/%�CY018:2�%)�,�R-/!j-/01FG26 32 8:2��A2�2� 17>=G01��*\ ;26%.-/!:CY�i7>�P%)�) 3C,2 f 268:C@(>-?2$�<8:C�01 3*&�A-A!>*& 326%.-/!:C��gh��� � ��!#�?�)7LMl%�(:-/%B!#�,%�Q��?�)SG2<-/=#=j-/�)�P!&%�01Fb*\�>X ��]&�,7>=G01�AFH 1!b%�(#��(# 3*#*&�,!b8#!G 1%�2�=:-�C�� c v (#�8:26�D�/�R2�8:C (q7>�A-?268#���A2 7h-,F>�? 1rJ�D-/!q 1!:-?C,C�8#�.-/%�� r\ 1�PQ �A��%�(#�'=:-/%�%)�,��!nC�0"8:26%��,�@2g-�CY%)8:-A0101FC��)�A-A%)�A*>K\Fk!G�,%�Q�����S#2� "!h%)(#�, "��(# ;*G*&�,!>8#!G 1%g26=j-�C��Jc

� �:!:-/0l%�(#�,�?�)�,%� ;C,-A0t=G�)��KG01�,7 Q� 1%�( %�(#�H8:2��'�/� �� � 32�%)(:-A%�Q�(# 10"�HCY018:2�%)�,�N*& ;-A���@-A7h2Q� 1%)( *\�,7>��!j26%)�.-/K#0"�926%��)8:C�%�8#�)�9CP-/!nK:�k8j26�A*n%)�h�J-A 1! 1!:2� 1�?(&%H "!&%��>%)(G�b!#�,%�Q��?�)S�� 2O��8#!jC�m%) 1�?!:-/0" 1%�FUh�%�(#� �E`Ja�� �/� -/=#=:-A�)�,!\%�2�%)��8:C�%)8G�)�+C,-/!#!G��%�CY��!\rJ�,�@2��,01F'K:�H8:2��A* %��$ "!&���,�<%�(:-/%R%)(#�(# ;*#*\�,!>8#!# "%����,=#�)�o26�,!\%@-A%) 1�?!k 32 8#!j26%)��8:C�%�8#�)�A*dc v (#�HQ��o-/S\!#�A2)2��A2��/�5%�(#���� � %)�AC@(#!# y8#�7h-,F>2� 17>=#0"F9C,-/8j26�D268:C@(q26%��)8:C�%�8#�)�'%��kK:�'��K:2�C�8#���A* c

� 7>�����>2���=#(# 326%� ;C,-A%)�A* -A01%��,�)!:-A%) "rJ�k%�� �� ��hlQ�(# ;C@( ;2 � -/ "!# 1!#�n=:�?=#8#0;-A�) "%6F 1! %)(#�-/!:-A01FG26 ;2'�/�+!#�,8#�.-/0�!#�,%�QR���)SG2%h< 32�� � V;X a V _G` �� ��� _ �JX:WYX&] ^ �+X ` � � ^ V ^ f � � � M.c � � � 32$-26%@-A%) 326%) 3C,-/0B%)�AC@(#!# y8#�D-A0;26�qC��?7>7>�?!#01F98:26�o*L 1!n%)(G�926�\C� 3-/0�2�C� 1�,!jC��A2%hd-/!j* �,0326�,Q�(G�,�)�Uhd-�2-/!n-A ;*> 1!h "!&%��,�)=#���,%) "!#�$(G 1��(Gmf*& "7>�,!:2� 1�?!:-/0I*#-/%.-&c

v (G�$��� -/0<�A� � � � 32O%�� �:!j*n- =:-A�@2� 17>�?!# 1�?8:2i2��,%g�/� a ��� _ �JXtWYX\] ^ %�(:-/% C,-/!q�,u&=G0;-/ "!%)(#�br?-/�� ;-A!:C��9 1! 268GK����AC�%@2 �l2)CY���)�o2�c � � ����=:�,�@-A%)�A2H�?![%�(#�>-?2)2�8#7>=#%� 1��!n%�(:-/%'%�(#�,�)�9-A�)�C���7>7 ��! C��?7>=:��!#�P!&%.2$8#!:*&�,��01F\ 1!#� 2�8#K����AC�%.2 �<=:�,�������)7s-/!:C�� ��! -n�@-/!G���L�A�'%)�o26%@2^h�-/!j*%)(:-A%'C������)�,03-/%� 1��!j2OK:�,%�Q��P�,!q268#K����ACY%@2 �d2)CY���)�o2i-A�)�9-k���T�:�AC�%� 1�?! �A�R%)(# 32iC��?7>7>�?!hC���7 =t�?m!#�,!\%) ;-A01 "%6F c

�#�?���,u#-A7>=#0"�Uh���!G�$CY��8#03*k%)�A2�%g2)C@(#�J��05C@(# "0;*&���,!k�?!q-$K:-/%�%)�,��Fk�A�<r?-/�� ;-AK#01�A2����,0;-A%)�A*9%)�2)C@(#��03-�26%� ;Ci=:�,��������7h-/!:CY���526�,!\%)�,!jC��HCY��7>=#0"�,%) "��! 26S\ 10"0;2%h?7>�,7>�?�)Fb2�=:-/!�h#�)�A-?*& 1!#� C���7 =#�)�,m(#�,!:2� 1��!�h4r\ ;268j-/01 f!A-/%� 1�?! -/K# "01 "%6Fgh4-A!:* 2��n��!lc�� � � CY��8#03* %�(#�,! K:�h-A=#=#01 "�A*[%��L%)(G ;2$2��,%�/�R*#-A%@-k%��>-?2)C��P�)%@-A 1!h%)(G�$8#!:*\�,�)0"F& "!#�9C���!j26%)��8:C�%.2O%�(:-/%+*&�,%��,�)7> "!#�+C (# "0;*&���,! � 2�2)CY���)�o2�c�ef%

Page 90: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � ( �

7> 1�?(&%HK:�k���?8#!:*�hl�����D�,u#-A7>=#0"�Uh %)(j-/%b2�C (G�J��0�C@(# "0;*&���,!n%)�,!j*[%)� -/01QN-,F#2'2)CY���)�s26 17 10;-A�)0"F(# 1�?( �?��01�AQ ��!h���A-�*& "!#�9C��?7>=#�)�P(#�,!:2� 1��!�h&2��,!\%)�,!:CY�HC��?7>=#0"�,%) "��! -/!:*h26=:�,0"01 "!#� �\ 1!\%)�,��=#�)�,m%@-/%� 1�?!b�/��� � � -/!:-A01FG26 ;2<7> "��(\%l�)�,rJ�o-/0J%)(j-/%�%)(#�gCY��7>=:��!G�,!&%5 1! �:8#�,!:CY 1!#�+-/0"0&%�(#�)�,�g2�C������A2 ;2 > rJ�\CP-/K#8#03-/��Fh26 f!,� �1c

ef! �PrJ�,�)F � � � -A!:-/0"F#2� ;2%h5%)(#�P!�h<%)(#�P�)� -/�)�h�?K:26�,��rJ�A* f *&�,=:�,!j*&�,!\%�MHr?-A�) ;-AK#01�o2%h<-n2��,%�/�+268GK����AC�%@2^h5-/!:*[%�(#� 268#K����ACY%@2 �52�C������A2H��! %�(#�J2��>r?-/�) 3-/K#0"�A2�c�� (#�,! -A=#=#0"F& "!#�%� � � %)�!#�,8#�.-/0�!#�,%�QR���)SG2%h�%)(G�L 17 =#01 3C� E%$-?2)2�8#7>=#%� 1��! 32 %�(#�q2)-/7 �L-?2 ���?����� � �<(# ;*G*&�,! 8#!# "%@2C������)�A2�=t�?!:*[%�� %�(#�9��K:2��,�)rJ�A*nr?-/�� ;-/KG01�A2^h %��@-A 1!# "!#�h=:-/%�%)�,��!:2$-A�)�9%)(#� 268#K����oC�%@2^hl-/!:* %)(#�(# ;*#*\�,! 8#!# 1% -�CY%) 1r?-A%) 1�?!:29-/�)�q%)(#� 268#K����oC�%@2 ��2)C��?�)�A2b��! %)(#�q��K:2��,�)rJ�A* r?-/�� ;-AK#01�A2Yc v (#����J-A0l�/�T-/=#=G01F\ 1!#��� � � %)�b!#�P8#�@-A0 !#�,%�QR���)SG2 32�%)�b���A*&8:C��+%)(#�H03-/�����D26�,%��A�<(G ;*#*&�P!>8#!# "%@2%)�h->=:-A�@26 "7>��!G 1��8j2H26�,%+�/�NC���7 =t�?!#�,!\%@2�%)(:-A%'7h-,F>K:�k7>�?�)�D�A-�2� 101Fh "!&%��,�)=#���,%@-AK#01� c v (#�C���7>=:�?!#�,!\%@2�-A�)�D���)%�(#���?��!:-A0<01 "!#�A-A��C��?7kK# "!:-/%� 1�?!:2 �A��%)(#�'�?K:26�,��rJ�A*kr?-/�� ;-AK#01�A2Yc

v (G�,�)�H 32%h\(#�AQ��,rJ�,��h\-b268#K#%�01�' 1!\%)�P�)=#���,%@-A%) 1�?!k=G�)��KG01�,7 Q� 1%�( � � � "!h 1%@2R-/=#=G01 ;CP-/%) "��!%)� C���!#!G�AC�%) "��!# 326%�!#�P%6QR����S#2��,c�ef!L%�(#�D26�\C� 3-/0B2)C� "�,!:C��o2%h#CY��7>=:��!G�,!&%.2 ����8#!j*LK&F � � � C,-/!8:268:-A010"F$K:�H 1!\%)�P�)=#���,%)�A*'K&F C���!j26 ;*\�,�) "!#�'%)(#�g7>�A-A!# 1!#�+�/�l%�(#��r?-/�� ;-/KG01�A24���)�?7�Q�(# ;C@(b%)(G�,F-/�)�NC���!j26%)��8:C�%��A* f -�2l 1!D%)(#��> rJ�\C,-/K#8G0;-/��F �,�Pu#-A7>=#01�B-/K:�ArJ��M.c �i�AQ��PrJ�,�)hY 1!D-HC��?!#!#�AC�%� 1�?!# ;2�%C���!\%)�,u\%�2�8:C@(L 1!\%)�P�)=#���,%@-A%) 1�?!> ;2��.-/���,01F>=:� 2)26 "K#01�gh:-�2�%)(#�D(# ;*#*\�,!h8#!# 1%.2�(:-,rJ�'!#�k�?K&r\ 1�?8:27>�A-/!G 1!#� �t%�(#�, 1�g�)�?01�b "!L%)(G�b7h-/=#=G 1!#�9 ;2H*\�,%)�,��7> 1!G�A*>*&F\!:-/7 ;C,-A0101F f -A!:*n��=:- y8#�P01F:M�K\F%)(#�'%)�.-/ "!# 1!#�b=G�)�\C��A2�2�c

�g�,rJ�,�)%�(#�,0"�A2)2^ht�?!#�9C,-/! 26%� 10"0<8:26��� � � -�2'-L*\ 17>�,!j26 1�?!L���A*&8:C�%� 1�?!n%)�J��0Xhl%)�h 1!:2�=:�AC�%%)(#�'S\ 1!:*#2��/�T���)�?8#=:2�%)(:-A%O���?�)7 1!h%�(#�$(# 3*#*&�,!h8#!G 1%g26=j-�C�� -/!:*h%)�A2�%i(\F&=:�?%)(#�A2��A2g-/K:��8#%%)(#�>7s- �����'*\ 17>�,!j26 1�?!:2H�/�gr?-/�� ;-A!:C��>8#!j*&�,�)0"F& "!#�h%)(#� �)�,=#���A26�P!&%.-/%) "��!:2YcLef! %)(#�sC�8#�)���,!\%26%)8j*&FUh:7kF9 1!\%)�,���A26%� 32O "!n-?2)C��,��%@-A 1!# "!#�k E�R-/!\Fh�/��%�(#�$=G�) 1!jC� 1=:-A05C���7 =t�?!#�,!\%@2��T&d�AC�%� 1rJ�,0"F�,!:C��\*&�R%)(#�R�,uGC��,=#%� 1��! � �)�P��8#03-/�5*& 326%) "!:C�%� 1��!��/%�(# ;25*& ;2�%) "!:C�%) "��!'Q��?8#0;*'K:��C@(:-/�.-�C�%��,�) f!,�A*iK\F- 7h- ���?�RC���7>=:�?!#�,!\% �?!hQ�(# ;C@(k���,��8G0;-/�N-/!:*>�,uGC��,=G%) 1�?!k=j-/%)%��,�)!j2�-/���HQ��P010d26�,=j-/�@-A%)�A*dc�ex�����8#!:*,h�%)(# 324�)�o268#0"%4QR��8#03*$ 1!:*& 3C,-/%���%�(:-/%<%�(#���)�P��8#03-/�)m��,uGC��,=#%� 1�?!b*& 326%) "!:C�%� 1��! ����W ^ =#03-oFD-A! 17>=:����%@-A!&%<=j-/�)%R 1!b%�(#�i "!&%��,�)!j-/0#���,=#�)�o26�,!\%@-A%) 1�?!k�A�l=:-A%)%��,�)!:2R*&�,rJ�,0"��=:�A*$K\Fb%)(#�g!#�,%�QR���)S*&8#�) "!#�b%)�.-/ "!# 1!#�Gc

�64 VXq `aWYL\G6( DHGALFDjJtZ\`aq1JTW �eGIW7W7`aE�J^d Dj[7G�� W7`"%�GIgjEH`aD . JXd��eB7G�GIW7EH]'V^WYL�- E E�.(bj[7JT]aJ�s .�eGIuYV^gHDHqpGIW\D dfJ�gL(`_EPbPB7EjEH`aW7shDH[ G !YW7GIg<unJ�`aW\DHE<J^d �+ �5k<`aDH[1qpG�v

Page 91: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

(�� ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

� � � ��� � ����� � 8�� � � � � � ��� 9 ��v (#�HCY���)���AC�%58:26� f -A!:*br�-A01 3*& 1%�F$�A�d 1!\%)�,��=#�)�,%.-/%� 1��!dMl�/� � � � �)� y8# "�)�A2l%)(j-/%RC��,��%@-/ "!926%.-/%) 326m%) ;CP-/0d-�2�268#7>=G%) 1�?!:2 K:�H7 �,%,c �H2<�x-/��-?2�e�-/7 -,Q�-A�)�UhJ!#�b���A26�A-A�@C@(kQR����Sk%�(:-/%R(:-�2�8#%� 10" "!,�A*� � � "! -hC��?!#!#�ACY%) 1�?!# ;2�%'C��?!&%��,u&%+(:-�2H�)�Pr& "�,Q��A*q-/!:*n%)�o26%)�o*L%)(#�A2��>-?2)2�8#7>=#%� 1��!j2 f �Jc �#c2h��8#010" 1!:-A�) ;-+h������/E ���i�,!#!G ;2 � �<(# 10"01 1=j2%h����������3�<017h-A!�h���� ���yMN26� e<%)(#�?8#��(\%� 1%R=#�)8j*&�,!\%�%)��) 1�?������8:2�01F$%��A26%B%)(#�A2���K:���������g-�C�%�8:-/0"01FDC���!j*&8:C�%� 1!#�D- � � �$cJef%5Q��?8#0;*b-A0;26�'K:�� 1!\%)�P�)�A2�%) 1!G�%)�b2��,�g(#�AQ Q��P010:2�8# 1%��A* !G�,8#�@-A0 !#�P%6QR����S#2�-/���Uh\26%.-/%) 326%� ;C,-A0101F 26=:�A-AS& "!#��h\%)� � � � -/!:-A01FG26 32�c

v -/Kj-�C@(#!# ;C@S -/!:* �4 ;*&�P010 f ��� � �yMNC��?7>=#�)�P(#�,!:2� 1rJ�,0"F$01 326%�%�(#�'-�2�268#7 =#%) "��!:2�8#!:*&�P�)01F\ 1!G�- � � � -A!:-/0"F#2� ;2Yc v (#�$7 �J26%� "7>=:����%@-/!\%g-�2�268#7 =#%) "��!:2gC���!jC��,�)!h%�(#�$�?K:26�,��rJ�A*>r?-/�) 3-/K#0"�A2f Q�(# 3C ( -A�)�Uh5 1!n%)(G ;2'C,-�2��Uhl%)(#�9(# 3*#*&�,! 8#!# "%@2 M.c�� � �� ;2HK:-?26�A* ��! %)(#� g�,!#�,�.-/0�� 1!#�o-/�� �\*&�,0 ffv -/K:-?C (#!G ;C@S � �5 ;*&�,0"0oh������ �JM5Q�(# ;C@(b-?2)268G7>�A2l%)(:-A%�-/0"0&r?-/�� ;-AK#01�A25-/��� a �JX&]xV;X#Z �JZ ^ h(:-,rJ�9X � �b` ����� �JV ^ ] � V � Zy]�W��$2�C������A2%h:-A!:*L-A�)� � V;XtW `�� ��� � W �E` ]�W���c

v (G��(# ;*#*\�,!$8#!G 1%> r?-/�� ;-/KG01�A2 �/ "!$%)(G ;24���,=#01 3C,-/%� 1�?! �A� f �<0;-A8#%�� � C���0"�,0103-/!:*�h ����� �JM<-A�)���K\r& "��8:2�01FhC��?!&%� 1!\8#��8j2�c!�i 3*#*&�,!h8#!# "%g-�C�%� 1r?-/%� 1�?!:2O�.-/!#�?�bC��?!&%� 1!\8#��8j2601F f �? 1rJ�,!q-9C��,��%@-/ "!=#�)�ACY ;26 "��! MgK:�,%�Q��P�,!7?q-/!:* ��c �i����7h-/0" 1%�Fh�/�+%)(#� *& ;2�%)�� 1K#8#%� 1�?![�A�+-�C�%� 1r?-/%� 1��! 2)C��?�)�A2' ;201�A2�2HC��,��%@-/ "! �l%)�h%)�o26%H!#�?�)7h-A01 "%6Fgh#%)(#� 26%.-/%) 326%� ;C,-A0<%)�J�?0 � � ��� f �i����8� 2� ;2%h ����� ?yM+Q�-?2 8j26�A*%)� C,-A0;C�8#03-/%�� %�(#�q26SJ�,Q�!G�A2)2$�A�H%�(#�q*& ;2�%)�) "K#8#%� 1��! �A�'(# ;*G*&�,! 8#!G 1%9-�CY%) 1r?-A%) 1�?!:2$�����b�A-?C ((# ;*#*\�,!n8#!# "%)hl7>�A-?268#���A*L�ArJ�,�i%�(#�b��8#010�2��,%'�/������� �L2�8#K����AC�%.2�c �J��7 �,Q�(:-/% 268#��=#�) 326 1!G��01FghX �JXtW��/�5%�(#� �D?)?$(# ;*G*&�,!>8#!G 1%@2�(:-�*h-D26 1�?!# �tC,-/!\%)0"F926SJ�,QR�A*k*\ ;26%��) "K#8#%) "��!�5%)(#� 26=#���A-�*>�/�-/010B-�CY%) 1r?-A%) 1�?!:2iQN-�2i!#�?�)7h-A05-/!:*n-A017>� 26%+-/0"Q�-,F#2gC��ArJ�,���A* %�(#�$Q�(#�?01� -�C�%� 1r?-/%� 1��!n�.-/!#�?�Uh���)��7 ? %�����c � r\ ;2�8:-/05C@(#�AC@Sb�/�T%)(#�D-�CY%) 1r?-A%) 1�?!h7h-/%��) 1u9CY��! �:��7>�A*k%�(# ;2����A268G01%,c

�g�,%)�,��7> 1!G 1!#�hQ�(#�,%�(#�,�D(# ;*#*\�,! 8#!# "%@2b-A�)�h-A010�0" 1!#�o-/�)0"F[���,0;-A%)�A* =#�)�ArJ�A*n%)�nK:�h7>�����*& ��sC�8#0"%���%�(#�i�?!#01Fb7 �,%)(#�\*b2�8#���?�A26%��A*k "! v -/K:-?C (G!# ;C@Sb-A!:* �4 3*&�,010 f �������yM< "!&rJ�?01rJ�A257h-/!#m8:-/0"01Fb 1!j26=:�AC�%� 1!#�'=:-A 1�)Q� 326�g=#01�?%@2��/�5%)(G�H2�C������A2 �?!>�A-�C@(9=:-/ "���/�58G!# 1%.2�c � 8:C (s-/!h-A!:-/0"F#2� ;2Q���8G0;* K:�D 1!&���A-?26 "K#01�H E��*\��!#�b�,u\(:-A8:26%� 1rJ�,0"F$����� �G? ?k(# 3*#*&�,!h8#!G 1%@2 f %�(#�,���$-A�)�=E����)?>268jC (=:-/ "�@2 MJhJK#8#%4���?�)%)8G!:-/%��,01FD%)(#��0" 1!#�A-A�) "%6FD-?2)268G7>=#%) "��!b 324!#��%RC���8:C� 3-/0J����� � � �"��%)(G�g26��0"8#%) "��! ;2�26 "7>=#0"F > �,!#(j-/!:C��o* � fxv -AK:-�C@(#!# 3C S � �4 ;*\�,010Xh �������yM� E�501 1!G�A-/�� 1%�Fk�?K#%@-A 1!:2Yc

�#8#��%)(#�P�b-�2�268#7 =#%) "��!:2bC��?!:C��,��! %)(#� J8:-A01 1%�F �/�+%)(#�s*#-/%.-&c��g!#�>798:26%D�,!:2�8#�)�>%�(:-/%%)(#�,���h-/���h!#�n7> ;2�26 "!#�n*#-A%@- f 2�8#K����AC�%.2 �����bQ�(G ;C@( 26�?7>�>r?-/�� ;-/KG01�q2)C��?�)�A2b-A�)�h��7 1%)%��A*tM-/!:*[%�(:-/%D%)(#�P�)�> 32 -n2�8��sC� 1�,!\%'-A7>��8#!\%'�/�+*#-A%@-\c �H-/%�8#�@-A010"FUhlQ� 1%)( !#�,%�Q��?�)S -/!j-/01FG26�o2%h

Page 92: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � (��

%)(#�,���b-A�)�b!#�h7> 32)26 "!#� -�C�%� 1r?-/%� 1��!nr?-A018#�A2+-/!:*LQ� "%)( -/0"7>�J2�% � ?)? ?>=:-A%)%)�P�)!:2'2)CY���)�o*L�/rJ�P��D? ?>(# 3*#*&�,!q8#!# "%@2%h:%)(G�b2)-A7>=#0"�b26 � �' ;2i7 ���)�'%�(:-/! 2�8��hCY 1�,!\%,cgef!L%�(# ;2��)�A2�=:�AC�%'-A%H01�A-?26%�h!#�,8#�.-/0l!#�,%�QR���)SG2g-/�)�'rJ�,��F>Q��P010l2�8# 1%��A*>%)� � � � -/!j-/01FG26 32 f -/!:*h 1!:*\�,�A*>7>�J2�%�2�%@-/%� ;2�%) ;CP-/0-/!:-A01FG26�A2@M@c

�g8#%�01 "�,�@2< 1!9%)(G�'*#-/%.-bC,-/! *& 326=#����=:����%) 1�?!:-/%��,01F 1!��:8G�,!:C��g%)(#�+-/!j-/01FG26 32�c�ef%�Q�-?2��A-�2� 101FC���! �j�)7>�A*$%�(:-/%R%)(#�P�)�gQ��,����!#� f 8#!# 1r?-A�) ;-A%)��M5�?8#%)0" 1�,�.2 ` �JX � a@`/^ W ^ f %)(G�,�)�+C,-/! Kt�g!#�?!#�UhKt�oC,-/8:2���%)(#��(G ;*#*&�P!$8#!# "%�-�CY%) 1r?-A%) 1�?!:2<-A�)��K:��8#!j* K:�,%�Q��P�,! ?H-A!:*��/M5-A!:*k-A0;2��H%)(:-A%�%)(#�,���Q��,���$!#�>�?8#%)0" 1�,�.2 ` �JX � � `�� V ` ��� W ^ �g%)(:-A%H ;2^h (# ;*G*&�,!L8G!# 1%.2iQ� 1%�(n�,u&%��)�,7 �,01Fb0"�/Q C��?�)���,m0;-/%� 1�?!:2�Q� 1%�(L-A010d��%)(G�,��(# ;*G*&�,!h8#!# "%@2�c v (G ;2�0;-?26%�%��A26%�QN-�2�*&�?!#�'K&F>r\ ;2�8:-/0d 1!:2�=:�AC�%) "��!h�/�%)(#� f �G? ? � �D? ?JM�C��?�)���,0;-A%) 1�?!k7s-/%)�� 1udc �i�'%)�J�?0;2�Q��,���g-or?-A 10;-AK#01��%��$%��A26%4���?��7k8#0"%) "r�-A�) 3-/%)���8#%�01 1�P�@2�c

ef! 268#7 7h-/��FUht "%HQ�-?2i����8#!:* %)(:-A% %�(#� 26%@-A%) 326%) 3C,-/0T-�2)2�8#7>=#%� 1�?!:2i����� � � � QR�,�)�97>�,%rJ�,�)F QR�,010HK\F %)(#� �<03-/8#% -/!:* � C ��01�,0"0;-/!j* f �������yMh!#�P%6QR����S�hD-/!:* ��8#�)%�(#�,�)7 ���)�n%�(:-/%26��7 � C (:-A�@-?C�%)�,�� ;2�%) ;CP2 �A�9%)(#� *#-A%@- =#�)�Ar\ ;*&�A* K\F C��?!#!#�AC�%� 1�?!# ;2�%>7>�\*&�,032 f 2�=:�AC� �tC,-/0"01FUh%)(#�9-A7>��8#!\%H�A��*G-/%@-+h4%�(#�b0;-?C Sh�/�N7> ;2�26 "!#�>CP-�26�o2H-/!:*n%)(G�b0;-�C@SL�A�R8#!# 1r?-A�) ;-A%)�b�?8#%)0" 1�,�.2 M7h-/SJ�g%)(#�P7 ;*&�o-/0lCP-/!:*& 3*#-/%��A2�������� � �$c

������8�� �� ����� �

� =#�) "!:C� "=:-/0IC���7>=:�?!#�,!\%@2�-A!:-/0"F#2� ;2�QN-�2�-/=G=#01 "�A*k%)�b%�(#�'(# ;*G*&�,!>8#!G 1%g26=j-�C��H�A�<%�(#�D2)-A7>��T03-/8#%s-/!:* � C���0"�,0103-/!:* f ����� �JM9!#�,%�Q��?�)S %)(:-A%hQ�-�2 -/!:-A01F � �A* K\F CY018:2�%)�,� -/!:-A01FG26 32k 1!26�AC�%� 1�?! �&c EGc��?c v (G� 2�%@-/%� ;2�%) ;CP-/0H%��J��0;2>8:2��A* Q��,��� _#a@` f ���)��7 %�(#� �i�,% v �J�?0;2>=:-?C S?-/�?���

�i�,!#!# 32� �<(# "0101 "=:2%h �������/MO-/!:*�� � � � f �i�?�)8� 26 ;2^h �����)?yM@c���Y�����)�b=:�,��������7> 1!#� - � � ��hl��!#�9C��?010"�AC�%@2g%)(#�9*#-A%@->%)�hK:� -/!:-A01F � �A*LK\FL=#���A26�,!\%) "!#�

-/010BC��?�)�)�oC�%)0"F&m�7h-/=G=t�o* %)�.-/ "!# 1!#�sC,-�2��A2i%)� %)(#�b%��@-/ "!#�A*L!#�P%6QR����S f Q�(# 10"�b%)(#�DQ��, "��(\%@2H-A�)����)� � �,! MRh5-A!:* 2)-,r\ 1!#�h%�(#�k(G ;*#*&�P![8#!G 1%D-�C�%� 1r?-/%� 1�?!:2H�,01 3C� 1%��A* K\Fn�A-�C@( %)�@-A 1!# "!#�h=:-/%�%)�,��!lcv (# ;2�=#���\C��A*&8G�)�DC��)�o-/%)�o2�-��G? ? � �����G( f (G ;*#*&�P!>8#!# "%@2 � %)�.-/ "!# 1!#�9=:-A%)%)�P�)!:2@M�7h-/%��) 1u9�/�(# ;*#*\�,!h8#!# 1%g-?C�%) "r?-/%) "��!:2Yc

v (G�9-�C�%� 1r?-/%� 1��!j2iQ��,���$%�(#�,!n8:2��A*L%)�>�?�,!#�,�.-/%��9->C������)�,03-/%� 1��!q7h-/%��) "u ��- �D? ? � �D? ?7h-/%��) 1u9�/�T%)(#�DC��?�)�)�P0;-/%� 1�?!:2�K:�,%�Q��,�,!h%�(#�'(# ;*#*\�,!h8#!# 1%.2%h#Q�(# 3C (q-A�)�$%�(#� > �?K:26�,��rJ�A*>r?-/�) "m-/K#0"�A2 �# "! %�(# ;2�-A!:-/0"F#2� ;2Yc

Page 93: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ? ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

v (G�LCY���)���,0;-A%) "��! 7h-/%��) "unQ�-�2b8:2��A* -�2b 1!#=#8G%b%)�n%)(G� � � ������� � v � � %)�J��0xc v (G ;2%)�J��0 C,-/03C�8#0;-A%)�A2$%�(#�L�P 1���P!&rJ�ACY%)���.2 f Q�(# 3C (�-/���L%)(G�L=#�� 1!:C� "=:-/0gCY��7>=:��!G�,!&%.2 M -/!:* %�(#�, "�-�2)2��\C� ;-A%)�A* �, 1�?�,!\r�-A018#�o2 f Q�(# 3C ( 1!j*& ;C,-A%)�h(#�AQ "7>=:���)%.-/!\%$�A-?C ( =#�� 1!:CY 1=:-A0gC���7>=:�?!#�,!\% ;2 MJh#-?2OQR�,010I-�2g-$7>�A-�2�8#�)�+�/��%�(#�DC�8#798#0;-A%) 1rJ�g-A7>��8G!&%R�/��r?-/�� ;-A!:C��D-�C,CY��8#!\%)�A*b�����,c v (#��)�A2�8#01%'�/�N%)(# 32'C,-/03C�8#0;-A%) "��! ;2'26(#�AQ�! "! v -/KG01� �&c����4 "%$CP-/! K:�98:26�A*n%)� *&�,%��,�)7> "!#�$(G�/Q7h-/!\Fk=G�) 1!jC� 1=:-A0lC��?7>=:��!#�P!&%.2�26(G��8#03* K:�$�,u\%)�.-�C�%��A* ������7 %�(#� �D? ?9(# ;*#*\�,!>8#!# "%@2Yc

v -AK#01� �&c���� v (#� �:�.26%5%)�,!DC��?7>=:��!#�P!&%.2 �,u&%��@-?C�%)�A*HK\F'%)(#� � � � � � � � v � � =G�)���?�@-A7 ���)�?7- �)�P=#01 3C,-/%� 1��!n�A��%�(#���<03-/8#% -/!:* � C ��01�,0"0;-/!j* f ����� �JMH!#�,%�QR���)Sdc �#�?�$�A-?C ( C��?7>=:��!#�P!&%�h%)(#�H�P 1���P!&r?-/0"8#�g ;2 0" ;2�%)�A*�h\-?2 Q��P010d-�2�%�(#�H=:�,�@CY�,!&%.-/�?�i�A�<r?-/�� ;-A!:C��'-?C,C���8G!&%��A* ���?��K&Fb%�(:-/%C���7>=:�?!#�,!\%)h#-A!:* %�(#�DC�8#798#0;-A%) "rJ��=:�,�@CY�,!&%.-/�?� �A��%)(j-/%+-/!:*h-/0"0l�A-/��01 "�,��C��?7>=:��!#�P!&%.2�c

����7>=:�?!#�,!\% �< 1�?�,!&r?-A018#� �4�,�.C��,!\% �A�&R-/�� ;-/!jC�� ��8G7k8#03-/%� 1rJ� �4�,�@CY�,!&%.-/�?�

� � c �)? ( E � � c � � c �� � c ��� ? E � � c � � E#c �� (\c E ��� �)( (&c � � ��c �E �\c �)? E E ? �&c � � � c@?� �\c � � � � � �&c � � �&c �( EGc@( � � (�� E#c ( �)(&c �� EGc�� � � ��� E#c � E���c@?� EGc@? � � ��� E#c � E �&c��� �\c ��� E � � �&c � E �&c@?�G? �\c �)?����)( �&c � � �&c �

�+2HC,-/!nK:�92��,�,!n 1! v -/KG01� �&c �Ch !G��!#�9�/�R%)(G�b�, 1�?�,!&rJ�oC�%)�?�@2�-�CPC���8#!\%i���?�$-90;-/�����b=#����m=t�?�)%� 1��! �/�+r?-/�) 3-/!:CY���>%)(#���:�.26%b=#�� 1!:CY 1=:-A0�C��?7>=:��!#�,!\%)h<Q�(G ;C@( -�C,CY��8#!\%@2 ���?�k%�(#�h7>�J2�%r�-A�) 3-/!:C��gh4��!G01F C��ArJ�,�@2 � c � B>c v (# ;2'�)�A2�8#01%D7h-,FLK:�h*&8G�>%)�q%)(#� *& ;2�%)�� 1K#8#%��A*[!:-A%)8#���>�/��)�,=#���A26�P!&%.-/%) "��!:2l��!b%�(#��(G ;*#*&�P!b8#!# 1%.2 f ��8#010" 1!:-A�) 3-/h �����/E&M.c�e�%B268G�����o26%@2<%�(:-/%<%�(#�,����-/����!#�7h- �����50;-A%)�,!\%<r?-/�� ;-AK#01�A258#!:*&�,��01F\ 1!#�g%)(G��(# ;*#*\�,!b8#!# "%@24%�(:-/%�hyK\F$%�(#�,7h2��,01rJ�o2%h,CP-/!9�,u&=G0;-/ "!7>�J2�%��/�T%)(#�'r?-/�� ;-/!jC��' 1!h%)(#�'(# 3*#*&�,!h8#!G 1%g2)CY���)�o2�c

v (G��� � � � � � � v � � %)�J�?0����,!#�P�@-/%��A* �D? ?qC���7 =t�?!#�,!\%@2^h �/�NQ�(# ;C@( ���>(:-?* ->0;-/������,!#��8G��(9�, 1�?�,!&r?-A018#� f�� �AMl%)�'K:�HCY��!:2� ;*&�,���A*$ 1!\%)�P�)=#���,%@-AK#01�Jc��H2<%)(#� �:�.26% �G?$C��?7>=:��!#�P!&%.2

Page 94: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � � �

-�C,C��?8#!\%i�����H�ArJ�,� � ? B �A��%)(G�$r?-/�� ;-/!jC�� f 2��,� v -AK#01� �&c �/MRh5e�*&�oC� ;*&�o* %)� �)�A2�%)�) 3C�%���8#�)%�(#�,�-/!:-A01FG26 ;2�%��k%�(# ;2�2��,%g-/0"��!#� c

v �H(#�P01=$ "!&%��,�)=G�)�,%l%�(#��*#-A%@-+hJ-/!:*b2��,�� E�d-/!\F'(# ;*G*&�,!$8G!# 1%B26=:-?C��gC�0"8:26%��,�@2lQ��,���<�����)7 �A*�/�����,��8#03-/�+-/!:*L�Pu#C��P=#%) "��!hQ��?�@*#2^h %)(#� _Ga@` 8#%) "01 1%�Fb���)�?7 �g�,% v �J��032 f �i�,!#!# 32����<(# 10"01 "=:2%h����� �/MRQ�-?2O8:2��A*k%��k7h-ASJ�i=j-/ 1��Q� ;2��H=#01�?%@2��A�<%�(#�'%)�,!hCY��7>=:��!G�,!&%.2�c �H2�Q� 1%�( %�(#�DC�018j26%)�P�-/!:-A01FG26 ;2^h5eO�?!#01Fq=#01�?%)%)�o* %�(#� f C��?�)���AC�%)0"F&m�7h-A=#=:�A*tM i0"8:26(GSJ� f ��� � �JM'-A!:* v -/�.-/K:-A! -/!j*� C���01�,0"0;-A!:* f ����� � Md�)�,�?8#0;-A�5-/!:*'�,u#CY�,=#%) "��!HQR���.*#2%h�%���7h-/SJ�5%)(G� =G01��%5�A-?26 1�P� %)�g 1!\%)�P�)=#���,%,c�i01%�(#��8#�?( �?!#01F � �nQ��?�@*#2 -/�)�q*& 326=#03-,FJ�A*�h�Kt�o-/�9 1! 7 1!:*[%�(:-/%9%)(G�,F Q��,��� =G01��%�%)�A* �?!C���7>=:�?!#�,!\%@2�%)(j-/%HQR�,�)�'���P!#�,�@-A%)�A*>���)�?7 %)(G�$(# 3*#*&�,!h8#!# "%H2�=:-�CY�9*#-/%.- ����� ` ��� QR���@*G2i 1!%)(#�'%)�.-/ "!# 1!#�92��,%,c

�5�,�� "01018j26%)�.-/%� 1��!�h&e<���,=#�)�\*\8:C��H%�(#�H=#0"��%��A�5%)(#�+�)�,�?8#0;-A��-/!j*s�Pu#C��P=#%) "��!9Q����.*#2���! %)(#��:�@2�%i%�Q�� C��?7>=:��!#�,!\%@2 f Q�(G ;C@( %����?�,%)(#�P�'-�C,CY��8#!\%O���?� � E#c � B �A��%)(G�$r?-/�� ;-/!jC���MRh: 1!G 1%) 3-/0"01F8:26 "!#� � � 2D-/!:* � � 2 %�� *& ;2�%) "!#��8# 326( ���,��8G0;-/�.2$-A!:* �,u#CY�,=#%) "��!:2 f �4 1�?8#�)� �\c@(JMRh�-/!j* %�(#�,!=#01�?%)%) "!#�b%)(G� QR���.*#2O%�(#�,7h2��,01rJ�o2 f �4 "��8#�����&c � M@c

�+2$C,-A! K:�L2��,�,! "! �4 "��8#�����\c@(/h�%)(G�,�)�9 ;2'!#� C�018j26%)�P�) 1!G� �A�H���,��8G0;-/� -/!:* �,uGC��,=G%) 1�?!Q����.*#2i�?![�, "%)(#�P�HC��?7>=:��!#�P!&% �$��� C���7>=:�?!#�,!\% �\c$ef!:*&�P�A*�h:!#�hC�0"�A-/�'CY018:2�%)�,�� 1!#� C,-/!nK:�26�,�,!9-A%�-/0"0 �5 1%B-/=#=:�A-A�@2 %�(:-/%B%)(#� �:�.26%�%�Q��'CY��7>=:��!G�,!&%.2<*&�H!G��%��,u\=#0;-A 1!b-A!&FDS& "!:*$�/�I�)�,�?m8#0;-A� � �Pu#C��P=#%) "��!9*& 326%) "!:C�%� 1��!Ic �#�?� 7 ���)�� "!&������7h-/%� 1�?!$��!9%)(G�i!:-A%)8#���i�A�l%�(#�gC���7 =t�?!#�,!\%@2^hel-/0;2��H�,uG-/7> "!#�A*i%�(#��=G01��%B�/�d%)(#�RQ��?�@*b26=:�,0"01 "!#�J2l��!b%�(#��2�-/7>�RC��?7>=:��!#�,!\%@2 f �5 1��8G�)� �\c � M@c

�g� C�0"�A-/�D=# ;CY%)8#��� �P7>�,�)�?�A2 ������7 %�(#��� � � =#0"��%9 1! �4 1�?8#�)� �\c � �, 1%�(#�,�,c v (G� �:�.26%C���7>=:�?!#�,!\% f �?! %)(#�>u\mx-/u\ ;2 MD-A=#=:�A-/�.2 %��nK:�L2��,=:-A�@-/%� 1!#�nQR���.*#2 �?! %)(#�>Kj-�26 32 �A�H%�(#�, "�rJ�/QR�,0�C�0"8:26%��,�@2 f ���)��7 01�Y��%H%)�q�) 1�?(&%�h4�?!#�hC,-A! 2��,�>Q��?�@*#2'Q� 1%�([rJ�AQ��P0�C�018j26%)�P�@2'26%.-/�)%� 1!#�Q� 1%)( Z � 2�-/!:* � � 2%h#%�(#�,! V � 2^h&%)(G�,!�h:-/0"0l%)(#�'QN-oF %)�9%)(#�'�) "��(\%)h5W � 2i-A!:* ` � 2 M.c v (#� 26�ACY��!:*C���7>=:�?!#�,!\% f �?! %)(#�>F\mx-/u\ ;2 MD-A=#=:�A-/�.2 %��nK:�L2��,=:-A�@-/%� 1!#�nQR���.*#2 �?! %)(#�>Kj-�26 32 �A�H%�(#�, "� 1!# "%) ;-A0�01�,%�%)�,�.2 � ���?�>�,uG-/7>=G01�Uh<7>� 26%bQR���@*G2>26%.-/�)%� 1!#� Q� 1%�( � -/!j* _ 2)C��?�)�L0"�AQ ��! %)(#�C���7>=:�?!#�,!\%)h#-A!:* %�(#�J2��D26%@-A�)%� 1!#�9Q� 1%�( � 2)C��?�)�'(# "��(#�,�Pc

� 7 ���)�N*&�,%.-/ 10"�A*b-/!j-/01FG26 324�/�I%)(#��� � � =#0"��%� ;25Kt�PFJ��!:*b%)(#�g2�C���=:�g�/�d%)(G ;2<%)(#�o26 ;2 �J-/!j*e 268j26=:�AC�%<%�(:-/%5%)�g 1!\%)�P�)=#���,% �4 1�?8#�)� �\c � ��8#010"FH��!#�RQ��?8#0;*'!#�,�A*H%)�gK:��-?C y8j-/ 1!\%)�o* Q� "%)(D%)(#�7h- �����B*& 326%) "!:C�%� 1��!j2T "!b%)�,u\%)mx26=:�,�oC (D7h-/=#=G 1!#� f 268:C@( -�2<Q�(# ;C@(bQ��?�@*#2�-A�)�g%)�'K:�gC�0;-?2)26 �:�A*-�2�> K# "0;-/KG ;-/0:���) 3C,-/%� 1rJ�A2 �&-A!:*L2��>��!dM@c �i�AQ��,rJ�,��hJ 1%g*&�J�A2g26�P�,7 C�0"�A-/��%�(:-/%�h# 1!qC���!G���)8G�,!:C��

Page 95: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

X

X

X

X

X

X

X

X

X

X

X

XX

X

X

X

X

X

X

X

X

X

X

X

X

X

X

X

XX

X

X

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR

R

R

R

RR

R

R

RR

R

R

R

R

R

R

R

R

R

R

R

R

�4 1�?8#�)� �\c@( � � �,��8G0;-/�g-A!:*>�,uGC��,=#%� 1��! Q����.*#2 f *&�,!G��%)�o*s���A26=:�ACY%) 1rJ�P01F$K\F � -/!j* � M�=G01��%�m%)�A*L�?! %)(#�"�j�@26%'%�Q��qC��?7>=:��!#�P!&%.2i�/�O-s=G�) 1!jC� 1=:-A0<CY��7>=:��!G�,!&%.2H-/!j-/01FG26 32H�/���<03-/8#%D-/!j*� C���01�,0"0;-A!:* � 2 f ����� �JMg!#�,%�Q��?�)Sdc v (#�"�:�.26%+C���7>=:�?!#�,!\%� ;2�%)(#� -/K:2�C� ;2�2)->-A!:*L%)(#� 26�ACY��!:* ;2�%)(G� �?�@*& "!:-/%��Jc

Page 96: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � � �

gross

head

mild

most

move

phase

pint

plow

post

prove

pull

pushboth

rouse

bowl

bread

spook

sweat

bull

bush

wash

were

wild

word

work

worm

choose

dead

deafdoll

dread

give

big

class

got

main

page

with

write

will

bus

beam

deed

dots

grape

fade

pitch

pump

ripe

slamwax

wake

bath

breed

buffbust

deal

dean

dreamheat

meld

mode

must

pink

port

posh

probe

puff

spool

sweet

wilt

wore

�4 1�?8#�)� �&c � � � �,��8G0;-/�D-A!:*[�,uGC��,=#%� 1�?![QR���@*G2 =#0"��%)%��A*n��! %�(#� �j�@26%D%�Q��qC���7 =t�?!#�,!\%@2H�/�-s=G�) 1!jC� 1=:-A0<CY��7>=:��!G�,!&%.2H-/!j-/01FG26 32i�/� �<0;-/8G%'-/!:* � C���0"�,0103-/!:* � 2 f ����� �yM+!#�,%�Q��?�)Sdc v (G ;2�:��8#���� 324 ;*&�P!&%� ;C,-A0�%)� �4 1�?8#�)� �&c@(+h��,uGC��,=#%l%�(#��2�=:�,010" 1!#� 24�/�:%�(#��QR���.*#2<-/����=#01�?%)%��A* "!:26%��A-�*�/�B%)(#�'�)�P��8#03-/� � �,uGC��,=#%� 1��!h03-/K:�,0;2Yc

Page 97: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� E ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

Q� 1%)( %�(#� �:!j*& 1!#� 2 ������7 %)(G� (G 1�,�.-/�@C@(# 3C,-/0NC�018:2�%)�,�9-A!:-/0"F#2� ;2^h�%)(#�hQR���@*G2k-A�)�nCY018:2�%)�,���A*%)���?�,%)(G�,�$ "![(# 3*#*&�,! 8#!# 1%D2�=:-�C�� ��! %�(#�>K:-?26 ;2'�/�+2�=t�P0101 "!#� f ����%)(#�?���@-A=#(\FtM+�@-/%�(#�,�D%)(:-A!26��8G!:* f =G(#��!#�?01�?��F:M@c��#���' 1!j26%@-A!:C��UhlQR�>2��,�b%)(#� J8# 1%��9*& ;2�%) 1!jC�%)0"FL=#����!#�?8#!:C��A* ; ����� �-/!:* ; ����� ;[=:� 26 1%� 1�?!#�A*>%)�?���,%�(#�,�)hG-�2�QR�,010d-�2 � ��� � �p-A!:* � � � �:c v (#�,�)� -/�)� -/0;2���h#(#�AQ�m�,rJ�,�)h,!\8#7>�P�)��8j2lC�018:2�%)�,�.2 %)(:-A%<7h-ASJ�<!#�+26�,!:2���=#(G��!#�?01���? ;C,-A010"F �?�<����%)(#�?���.-/=#(# 3C,-/0"01FUh?268jC (-�2 6 � � � � �/9 � � -/!j* 6 � � � � � ���� �J%)(#�A2���=#����K:-AK#01F -/�� ;26�N*&8#�R%)�H%�(#�� "!#(#�,���,!&%B*& 326%)�?�)%� 1��!D 1!r& "�,Q� 1!#� -$01�AQ�mx*& 17>�P!:26 "��!:-A0 =#0"��%��\%)(#�PF>Q��?8#0;*>=#���A268#7s-/K#0"FbKt� C������)�ACY%)01F9*\ ;26%� 1!#�?8# ;2�(#�A*K&Fh-b2�8#K:2���y8G�,!&%gCY��7>=:��!G�,!&%Pc

�#�?�$CY��7>=#0"�,%)�P!#�A2)2^hlei "!:26=:�AC�%��A*L%)(G�k=:-A 1��Q� ;26�9=#0"��%@2H�����'�,rJ�,��FnC��?7kKG 1!:-A%) 1�?!n�/�N%)(#��:�@2�% �D?HC��?7>=:��!#�P!&%.2 f %�(#�,����-A�)�E �g268jC (DC��?7kK# "!:-/%� 1�?!:2 Mj-/!:*H����8#!:*'!#��!G��%)(j-/%526�P=:-/�.-/%)�o*�)�,�?8#0;-A�<-A!:* �,uGC��,=G%) 1�?!HQ��?�@*#2l 1! -/!\FHQ�-,FJc v (#�RC���!jC�018:2� 1�?!$ ;2 (G�,!:C���%)(j-/% � � � =#���Ar& 3*&�A2!#�n�,r\ ;*&�,!jC��k�A�'-h�)�,�?8#0;-A� � �,u#CY�,=#%) "��! *\ ;26%� 1!:CY%) 1�?! K:�, 1!G�n�,!:C��\*&�o*[ 1! %)(G�>(# ;*G*&�,! 8#!G 1%26=:-?C��'�/��%�(#� �T03-/8#%g-A!:* � C ��01�,0"0;-/!j* f ����� �JM�!#�,%�QR���)Sdc

� ��� ��� �N�� ���5���������#� I� � ��H��R� � +��� 0��t���

� %�(# 1�.*[*& "7>�,!:2� 1�?!n�)�A*&8jC�%) "��! %)�AC@(#!# y8#�b%�(:-/% a �JZ � � K:�>8:2��A*[%)�q-A!:-/0"F#2��>%)(#�9(# 3*#*&�,!8#!# 1%g2�=:-�CY� 32 ��` X �JX#V a@` ��� V ^Pa � V V;X ` X&] �+X ` ���o^ V ^ f ��� � M.c�� (# 10"��� � � 26�P�,S#2�%��b7h-/u\ 1m7> � �g*\ ;26%.-/!:CY�A2 K:�,%�Q��P�,!>*G-/%@-b=:�� "!&%.2%h ��� � QR���)SG2�Q� 1%�( � � �JZ _#^ �/�B=:-/%�%)�,��!:2%h\%)�)F\ 1!G�b%)�7h-/u\ 17> � ��K:�,%�Q��P�,!#m����)�?8#=h*& 326%.-/!:C��o2 Q�(# "01��7> "!# 17> � E!#�gQ� 1%�(# 1!Gm �?�)��8G=L*\ ;26%.-/!:CY�A2�c!��� �C���8#03* K:�n8:26�A* %�� *& ;2�C��ArJ�,�k E�'%)(G�7> ������8#=j2 ���/�D�)�P��8#03-/�h-A!:* �Pu#C��P=#%) "��! =j-/%)%��,�)!j2 -A�)�Q��,0"01mx26�,=:-A�@-A%)�A*> 1! (# ;*#*\�,!h8#!# 1%g2�=:-�CY�Jc

v (G�,�)� -/���Uh<(#�AQ��,rJ�P�)hl7>�,%�(#�\*&��0"���? ;C,-A0 ���A-�2���!:2'%)(:-A%b=#�)�oC�018:*\�b%)(#�>8j26�>�A����� �� 1!%)(#�qC�8#���)�,!\%926%�8:*&FJc �4 "�@26%�01FUh<�?!#01F -[2�7h-/0"0�268GK:26�,%9�/� Q����.*#2b 1! %)(#�h%��@-/ "!# 1!G� 2��,%b(:-�2Kt�P�,!L03-/K:�,010"�A*h-�2 > �)�,�?8#0;-A� �:��� > �,uGC��,=#%� 1��! �& 1!q%)(#�D01 "%)�,�.-/%)8G�)� f g018j26(#SJ�?h ��� � � � v -A�@-/Kj-/!� � C���01�P010;-A!:*�h ��� � � M@c � ��� � K:-?26�A* ��! ��8:26%q%)(# 32 2�8#K:2��,%h7h-,F !G��%L=G�)�\*&8:CY� -A! 1!\%)�,��=#�)�,%.-/%� 1��!n%�(:-/%' 32 ���,=#���A26�,!\%@-A%) "rJ� ����� -/0"0 � ?)? ?L%)�.-/ "!# 1!#�hQR���@*G2�c�� �AC���!j*&01FUhl "%H(:-�2Kt�P�,!'Q�-/��!#�A*'%)(:-A% ��� � 26(#�?8#0;*'��!#0"FHK:��-/=G=#01 "�A*H �G%)(#�,���< ;2526�?7>�< "!:*&�,=:�,!:*\�,!&%l�Pr& 3*&�,!:C��f �Jc �#c'h:r\ ;- � � � M�%)(j-/%'%)(#�b�?�)�?8#=# 1!G�J2H8:26�o* "!n%)(#�9-A!:-/0"F#2� ;2'-/���9-/0;2��q-�C�%�8:-/0"01FL8j26�A*LK\F%)(#�9!#�,%�Q��?�)Sn "![�?�)�J-A!# � 1!#�q%)(#�>(G ;*#*&�P![8#!G 1%D26=:-?C�� f �i�,!#!# 32 � �<(# "010" 1=:2^h �������/M.c v (#��)�A-?26��!b�����B%)(# 324�)�A2�%)�� ;C�%� 1��!b 324%)(j-/% ��� � ;2<2���7>�P%) 17 �A2 -AK#01��%�� �j!:*$r& "�,Qg24�A� %�(#��(# 3*#*&�,!

Page 98: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� !�#1����� � � � � �

8#!# 1%N26=:-?C��'%)(:-A%HCP-/! `�_J_ W `�� %)� C���! �j�)7 -/!\Fh-/��K# 1%��@-/��F>������8#=G 1!#�9�/�B%)(#�'%��@-/ "!# 1!G�9*#-/%.-&c���oC,-/8:2��k!G�, 1%�(#�,�'%)(#� �� ��!#���D%)(#� � � � C���!:*\8:C�%)�o*[-AKt�ArJ�>� -,rJ�>-A!&F 1!:*\ ;C,-A%) 1�?!

%)(:-A%$%)(G�>�)�,�?8#0;-A�)m��,uGC��,=#%� 1��! *& 326%) "!:C�%� 1��! Q�-?2$r?-/01 3*�h<e+*&�AC� 3*&�A*n%)(#�,���>Q�-?2 !#�nr?-A018#�9 1!C���!:*\8:C�%) "!#�9-���� � ��!h%�(#� �T03-/8#%+-/!j* � C���0"�,0103-/!:* f ����� �yMN*#-A%@-&c

� ��� ��� � ���G� �����t� ��

e�! 268G7>7h-/��FUhA%6QR�b2�%@-/%� ;2�%) ;CP-/010"F&m�K:-?26�A*br& 3268:-A01 � -/%� 1��!9-A!:-/0"F#2��A2 �A�5%)(#�g(# 3*#*&�,!>8G!# 1%R26=j-�C���/��%�(#� �<0;-A8#%+-/!:* � C���01�,0"0;-A!:* f ����� �JM�!#�,%�Q��?�)S>���,rJ�A-A01�A*k!G�> 1!\%)�,��!:-/0l���,=#���A26�,!\%@-A%) "��!:-A0*& ;2�%) 1!jC�%) "��!>K:�,%�Q��P�,!h�)�,�?8#0;-A�g-/!:*h�,u#CY�,=#%) "��!>=j-/%)%��,�)!j2�c

�g=:-/��% ������7%�(#�>-AK:�/rJ� �:!:*\ 1!#�?h4%)(G�>2�%@-/%� ;2�%) ;CP-/0R-/!:-A01FG26�A2H%�(:-/% eHC,-/���) "�A*L��8#%D(:-,rJ��)�A2�8#01%��A*> 1!>���,Q !#�PQ 1!:2� 1�?(&%.2� 1!\%)�9%)(#�' 1!\%)�P�)!:-A0526%)��8:C�%�8#�)�D�/��%�(#�'�)�,=#���A26�P!&%.-/%) "��!:2^h#!#���-/!n-A01%��,�)!:-A%) "rJ�'-/!:2�Q��,�+-�2�%)�9(#�AQ�C��?!#!#�ACY%) 1�?!# ;2�%�!#�,%�Q��?�)SG2�-/���$-AK#01�D%)�b(:-A!:*&0"�$�)�P��8#03-/�-/!:*h�,u#CY�,=#%) "��!>=j-/%)%��,�)!j2�26 1798#0"%@-/!G�,��8:2�01FJc

�B-/�)%'�A��%)(G�k=#����K#0"�,7 0" 1�A2gQ� 1%)(n%�(#� 26 � �9-/!:*n!:-/%�8#�)�9�/�N%)(#� C@(#�J2��,! 26 "7k8#03-/%� 1��!��H-0;-/�����h!#�,%�QR���)S -/=G=#01 "�A* %)� - > �)�o-/01m�Q��?�)03* %.-�2�S �2h<Q� 1%)( -A017>� 26% � ?)? ?n%)�.-/ 1!G 1!#�n=:-A%)%��,�)!:2-/!:*��G? ?k(# 3*#*&�,!q8#!# "%@2�c � (# 10"�'%)(#�D7h-/=#=G 1!#�b�A��7 ��!#� 26F\010;-AK# ;C"�<!#�?01 ;2�(LQR���@*G2i%)�>%�(#�, "�=#�)�?!&8#!jC� ;-A%) 1�?!:2H ;2i�?!#�b�/�N%)(#�b7 �J26%+=t�?=#8#03-/�D-/!:* C@(:-/0"01�,!#�? 1!#� �,u#CY�,=#%) "��!q%@-�2�S#2H "!n%)(#�01 1%��,�@-A%)8#���Uhl 1%'7h-,FL!G��%$K:�> 3*&�A-A0101F 268# "%)�A*L�����D%)(#� ` X ` ���,^ V ^ �/�g�,uGC��,=G%) 1�?![(j-/!:*&0" 1!#�hK\FC���!#!G�AC�%) "��!# 326%R!#�,%�Q��?�)SG2�c

v (G�,�)�h-A�)�hr?-/�� 1��8j2 ���A-�2���!:2$�����b%�(# ;2'8#!:268G 1%@-AK# 10" 1%�FJc v (#�>7 �J26% 26�,rJ�P�)�>=#����K#0"�,7 ;2%)(:-A%� 1%B ;2�*& ��sC�8#0"%<%)� -�*&� y8:-A%)�,0"Fbr& "�,Q %)(#�+C��?7>=#01�P%)��(G ;*#*&�P!k8#!G 1%R26=:-?C��H�A�l%)(G�i%��@-/ "!#�A*!#�,%�Q��?�)Sdc4ef!:2�%)�A-?*�hJ��!#��798:2�%4���A26�?�)%�%)�H0"�AQ�mf*& "7>�,!:2� 1�?!:-/0G268#7 7h-/�� 1�A2 �?!bQ�(# ;C@(9-'268#K:2��,%�/�b=j-/%)%��,�)!j2 ;2>=#0"��%�%)�A* � -/!:* -?2>%)�AC@(#!# y8#�o2k%)(:-A%L�,!j-/K#0"�[%�(# ;2h*& "7>�,!:2� 1��! �)�A*\8:C�%) "��! 1!#�,r\ 1%.-/K#0"F>CY��!:C��o-/0B*&�,%@-A 105-A!:*nC,-/! *& ;2�%)�?�)%g 17>=:����%@-A!&%����,0;-A%) 1�?!:26(G 1=:2 f -?2OQN-�2i!#�?%)�A*h 1!%)(#�D-/!j-/01FG26�o2�-/K:�ArJ��M�%�(#�,F 26(#�?8#0;*hK:� %��)�A-A%)�A*>Q� "%)(nCP-/8#%� 1��!Ic

� ��8#�)%�(#�,�b=#����K#0"�,7uh�%)(:-A%k 32 ���,0;-A%)�A* %)� %)(#� 26 � �h�/�'%�(#�L!#�P%6QR����S�h� 32$%)(#� C��J2�%>�/��)8#!#!G 1!#�g7k8G01%) "=#01�T26 1798#03-/%) "��!:2 �t 3*&�A-A0101Fgh,��!#�g2�(#��8#03*b-/!:-A01FG26�R7h-/!\F'268jC (D!#�,%�Q��?�)SG2 f �/rJ�P�*& ��d�,���,!&%g%)�� ;-A0;2 MN%)�q*& ;2�%) "04%�(#�, 1� �&WYX:W �)` � =#�)�?=:�,�)%� 1�A2^h "!:26%��A-�*L�A�RK:-�2� 1!#�qC��?!:C�018j26 1�?!:2i�?!��!#� �h=:� 2)26 "K#01F -A%�F&=# 3C,-/0 �q2� 1798#0;-A%) 1�?!lc��i�AQ��,rJ�P�)h:%)(#�D%) 17 �$-A!:*n�)�A2���8#�.C��A2� 1%H����y8G 1�)�o2%)� %)�.-/ 1!�-/!j* -A!:-/0"F#2�� f -/!:* %)�A2�%h26%.-/%� ;26%� ;C,-A0D-�2)2�8#7>=#%� 1�?!:2 �����YM 268:C@( 03-/�����n!#�,%�QR���)SG2

Page 99: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ( ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

=#�)�ACY018:*&�o2 %)(G ;2�=:�J2�26 1KG 101 "%�FJc�5 1!:-A0101Fgh& 1%� 32�*& ��sC�8#0"%�%��k "!&%��,�)=#���,%�%�(#�'�)�A2�8#01%.2O�A��%)(G�$2�%@-A%) ;2�%) 3C,-/05-A!:-/0"F#2��A2OQ� "%)(#�?8#%

26=:�AC� 3-/01 326%5S&!G�/Q�0"�A*&�?���/�d%)(#�R%@-?26SbK:�, 1!G�'26 "7k8#03-/%��A* c�#���B 1!:2�%@-/!jC��Uh�%��'26�,!j26 1KG01F' 1!\%)�,��=#�)�P%%)(#�'CY018:2�%)�,�� 1!#�D 1!h%)(#� � � ��*& 3-/�?�@-/7s2� 1!��4 "��8#���A2 �&c (b-/!:* �\c � h:2���7>�+S&!#�AQ�0"�A*&���+�/�B%)(#� 17>=:����%@-A!&%�=#����=:�,��%) 1�o2i�/�RQ��?�@*#2^hl-/!j*L%)(#�'�x-�C�%����@2g��!nQ�(# 3C (q%)(#�,Fh7> "��(\%�K:�bC�0"8:26%��,�)�A*,hQ���8G0;*>K:�$r?-/0"8:-/K#0"�Jc

� (G 101�+7h-/!\Fb 17>=:�?�)%@-A!&%R 1!:2� 1�?(&%.2 (:-,rJ�'C��?7>�����)��7 1!\rJ�A26%� 1�J-A%) "!#�'0;-/�����,mx2)CP-/01�gh > �)�o-/01mQ�����0;* �<%.-�2�S#2^hO "%b(:-�29�)�AC��P!&%�01F Kt�P�,! -A�)��8G�A* %)(:-A%>CY��!#!#�oC�%) "��!# 326%b�)�o26�A-A�@C@( 26(G��8#03*�h�-�2Q��,0"0oht���\C�8j2$-/%�%)�,!\%) "��!n�?! 1!#mx*&�,=G%)( -/!:-A01FG26�A2H�/�O26 "7>=#01�P� �E` � � ��` ] � �� =#����K#0"�,7h2 f � ;2�%)�,��h����� ��-JMb%)(:-A%>CP-/=#%�8#�)�h%)(G� �o2)26�P!:C��>�A�'%)(#�h%.-�26S -A%b(:-/!:*,h�Q� 1%�(#��8#%9%)(G�LCY��7>=#0" ;C,-A%) "��!:2�/�'%.-�26S\mx26=:�AC� �dChC���!:2� ;*&�P�@-/%� 1�?!:2 ��� c � ;26%��,� f ����� ��-yM9!#�?%)�A* %)(:-A%k%�(#�q26%�8:*&F �/�'03-/K:���.-/m%)����Fb=#�)�?K#01�P7h2<-/0"01�AQg2�2� 17>=G01�,�B-/!:-A01FG26�A2<%�(:-/%N-/�)�+7>�������A-�2� 101FD 1!\%)�,��=#�)�P%@-/KG01�UhJ-A!:*k�A��%)�,!=#�)�Ar\ ;*&�A2�!#�ArJ�,0l "!:26 "��(\%@2i%�(:-/%HQR��8#03* �?%)(#�,��Q� ;2��bKt�D01� 26%H "!L%)(G�9C�018#%�%)�,���A�R%@-�2�S&mx26=:�ACY �dC*&�,%@-A 10xc��J8:C@( "!:26 "��(\%@2'C���8G0;*n%)(#�,! Kt� %)�A2�%)�A*L�����Dr�-A01 3*& 1%�FL�?! 0;-A�)�?�,�b2�C,-/0"�Uhl�)�A-A01m�Q�����0;*26 1798#03-/%) "��!:2Yc

eb=#����=:�J2��[%��[����0"01�AQ - 26 "7> 103-/�b2�%)�.-/%)�P��FJc e$Q� 10"0i!#�AQ %)8G�)! %)� %�(#�n-A!:-/0"F#2� ;2k�A�9-267h-A010�!#�,%�QR���)S %��@-/ "!#�A* �?! - 2� 17>=G01�Uh�C�03-�2�26 ;CL�Pu#C��P=#%) "��! %@-?26S �[%)(G� � Z � W �������L%@-�2�Sf � 8#7>�,0"(:-/��%� � C ��01�,0"0;-/!j*�h ����� (JM@c v (#� 267h-A010 !\8#79K:�,���A��%)�.-/ 1!G 1!#�9=:-/%�%)�,��!:2g-/!:*h%)(#�01�AQ�*& "7>�,!:2� 1�?!:-/0" 1%�Fh-/0"01�AQ �?!#�>%�� �?K:26�P�)rJ� *& 1���AC�%)0"FL(#�AQ =:-/%�%)�,��!:2$-A�)�9�)�,=#���A26�P!&%��A*L 1!%)(#�R(# ;*#*\�,!b8#!# "%<2�=:-�C�� c v (# 324��=#=:�?�)%)8G!# 1%�F$0"�A-�*G24%)�'-A!b8#!#�,u\=:�AC�%��A*$-A!:* �H�����B7kFH%�(#�A2� ;2�hC���8:C� 3-/0 "!:26 "��(\%� "!&%��b%)(#�'!:-A%)8#���$�/�B�,uGC��,=#%� 1�?!:2� 1!qC��?!#!#�AC�%� 1�?!# ;2�%�!#�,%�QR���)SG2�c

� ��� � 2 � � � �K0 2\* � � � -, � � �4, * ���

�i!G�> ;2�268#�h%)(j-/%b(:-?2$Kt�P�,! %@-ASJ�,! �����D���@-A!&%��A* 1! %�(#�q26%�8:*& 1�o2 �)�Pr& "�,Q��A* 26�L�x-A�)h� ;2'%)(#� ;2)2�8#�$�A��(#�AQ �?!#�b*&�P%)�,��7> 1!#�o2TQ�(G ;C@(L%)�.-/ "!# 1!#�b=j-/%)%��,�)!j2H-/��� > ���,��8G0;-/�.2 �#�?� > �,u#CY�,=#%) "��!:2 �1c�j�?���,uG-/7>=#0"�UhJ 1!���(:-A=#%)�,� E�h#!\8#7>�P�)��8j2�26%�8:*& "�A2�Q��,���D*&�A2)CY�) 1K:�A*>Q�(#�P�)�'!#�,%�Q��?�)SG2�Q��,���01�A2� 1��!G�A*�h<-A!:* *& ;2�26�\C� 3-/%� 1��!j2 K:�,%�Q��P�,![%�(#�>0"�A26 "��!#�A* !#�,%�Q��?�)SG2 �<-AK# 10" 1%�Fn%)�n(j-/!:*&0"�>=#���,m

� ����`aEHDHG�g<McOoQ�Q�STV�U k<VXE EHunGAbP`"! bIV^]a] .FgHGidfGIgHgj`aW7stDjJ$DH[7GeEHDHBnL).tJ^d�biJ�W7W7GobPDH`aJ�W `_EjD�]aGAV^gHW7`aW7s L).\WYV^q1`'bPE B7EH`aW7s]aJXk +HL\`aq1GIW EH`aJ�WYV^]�GIWnbPJ7L\GIgHE$M @�V^m\m�GIg 9���`aEHDjGIg'9): � `a]aGIE'97OoQ�Q� �U69 (7B7D 4 (nGI]a`aG�%�G<[ `_ElgHG�q VXgjm\E [nV�%�G1(7gjJ4V�L(GIggjGI]aG�%�VXWnbPGtVXE<klGI]a] v

Page 100: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � � �

*&� �:!#�o* > �,u#CY�,=#%) "��! � -/!:*"> �)�,�?8#0;-A� �J=:-A%)%)�P�)!:2�Q��,���i7>�o-�268G�)�A* cBef!k%�(#� �:�.26%�2� 1798#0;-A%) "��!b�/�%)(# 32<C (j-/=#%��,�)hJe5C��?!:*&8:C�%��A* r?-A�) 1�?8:2�26%.-/%) 326%� ;C,-A0:-/!:-A01FG26�A25�/�l%�(#��(# 3*#*&�,!b8#!G 1%B26=:-?C��i�A�d%)(#��T03-/8#%+-/!j* � C���01�,0"0;-A!:* f �������yM�!#�P%6QR����S�h# "!n-/! -/%�%)�,7>=G%�%)� *&�,%)�P�)7> "!#�H �B%)(G� g018:2�(#SJ�f ��� � �JMR-/!:* v -/�.-/K:-A!q-/!:* � C���01�P010;-A!:* f ����� � M�> ���,��8G0;-/� �\-/!:*"> �,uGC��,=#%� 1��! �/=:-A%)%��,�)!:2�Q��,���26�,�?�)�,� -/%)�o* c

�g�/Q�QN-�2' 1%D*&�,%��,�)7> "!#�A*h%)�LQ�(G ;C@( C,-A%)�,�?����F[�A-?C ( =:-A%)%)�P�)! f ���$�o-�C@([=:-A%)%��,�)! "! -268#K:2��,%H�A��=:-/%�%)�,��!:2 MNKt�P01��!G���A* $ ef!n-/0"04%�(#�b2�%)8:*\ 1�A2g*&�A2�C��) "Kt�o*L26�9�x-/�)hd%)(#�D7>�,79Kt�P�@26(G 1=�/�l%�(#�A2��HC,-A%)�,�?���� 1�A2�(:-�2�Kt�P�,!>*\� �:!#�A*b 1! -�*\r�-A!:C��Uh\8:26 "!#�'S&!G�/Q�0"�A*&�?�i�A�5%)(#�g�)�,�?8#0;-A�) "%) 1�o28#!:*&�,��01F\ 1!#�+%)(#�g%)�.-/ 1!G 1!#�D26�P%,c v (#�A2��i���,��8G0;-/�� 1%� 1�A24QR�,�)���P 1%)(G�,�< 1!j*&8:C��A*$K\Fb 1!j26=:�AC�%� 1��!9�/�- =G�)�,m��,u\ ;26%� 1!#�D2��,%��/�5*G-/%@- f �Jc �#c2h�%)(#�g=#����!\8#!:C� 3-/%) "��!9�/� �T!G��01 326(9Q��?�@*#2 �&���R%)(#�g7h-A=#=# 1!G��/���<!#��0" ;2�(>rJ�,�)Kj2T%��$%�(#�, 1��=:-?26%�%��,!:26��������7h2 M5�?��Q��P�)�g�,u&=G01 ;CY 1%)0"F'K#8# 10"%� 1!\%)�'%)(#�+%)�@-A 1!# "!#�26�,%<%�(#�)�?8#��(9%)(G��8:26���A�5-/!9-A�)%� �dC� 3-/0#��8#01�R%)�'���P!#�,�@-A%)�����,��8#03-/�<=j-/%)%��,�)!j2 f �Jc �Gc'h ��8#010" 1!:-A�) 3-� ��(:-A%)�,��h�������yMg-?2OQR�,010I-�2��,u\=#01 3C� 1%��,uGC��,=#%� 1�?!:2�c

�g�,�)� ei�,uG-/7> "!#�$%�(#� � Z � W ��� ��� %.-�26S f � 8#7>�P01(:-A�)% � � C���0"�,0103-/!:*�h �����)(yMJh�-h%@-�2�S%)(:-A%>2� 17> "0;-/��01Fn(:-?2>-nQ��,0"01mx*&� �:!#�o*�h�-A�)%� �dC� 3-/0Xh > �)8#0"� �4%�(:-/%>QN-�2b8:26�o* %)� ���P!#�,�@-A%)�q%)(#�%)�@-A 1!# "!#� 26�,%�h# 1!:C�0"8:*& "!#�9-/!q�,u&=G01 ;CY 1%��,uGC��,=#%� 1��!h%��k%�(:-/%g�)8#0"�Jc v (#��y8#�o26%) "��!q%)(:-A%H-A�) ;2��A2 1! %)(G ;2>2� 1798#0;-A%) 1�?! ;2kQ�(#�P%)(#�,� %)(#�n!#�P%6QR����S -?C�%)8j-/010"F 0"�A-/��!:2k%)(G�n�,u&=:�ACY%)�A* �)8#0"�Uh���� 1!:2�%)�A-?*s "!:*&8:CY�A2�-A!L-A01%��,�)!:-A%) "rJ� > �)8#0"� �&%�(:-/%gC,-A!q-/0;2��b7h-/= %)(#�H=j-/%)%��,�)!j2iC��?�)���AC�%)0"FJc5e �5 1%C,-/!hK:�D26(#�AQ�!h%)(:-A%i%�(#�H�,u\=:�AC�%��A*k�)8G01�H 32�!#��%�0"�A-/��!#�A*�hGC,-/!hQ�� 26%) "010I2)-,F>Q� 1%�(qC��,�)%.-/ "!&%�FQ�(# ;C@(>=:-A%)%)�P�)!:2gC���!j26%) "%)8#%��'%)(#�D26�P%��/��> �,u#CY�,=#%) "��!:2 ��$ v (#�' 17 =#01 3C,-/%� 1��!j2 -A�)� *& ;2�C�8:2)2��A* c

� ��� ��� �>� � � � +4�:��� ���

v (#� � 8G01���/� � � � � %@-?26S$QN-�2<=#����=:�J2��A*kK\F � 8#7>�,0"(:-/��%<-A!:* � C ��01�,0"0;-/!j* f �����)(yM�-?2�- 2� 17>m=#01�'-A!:-/0"���?F %��b%)(#�'%.-�26S �/�B7h-/=#=G 1!#� �T!G��01 326(hrJ�,��K:2 %��b%)(#�, "��=:-?26%g%)�,!j26�i���?�)7h2Yc�e�! %)(#�26=# "�) 1%B�/�52� 17>=G01��03-/K:���.-/%����)F9=#����K#0"�,7h2%hA 1%R2��,�)rJ�A*b-?2�-/!9 1010"8:26%��@-A%) 1�?!k�A�l%�(#����8#!:*#-A7>�,!\%@-A0=#�)�?=t�P�)%) "�A2 �A�<%�(#�H7h-A=#=# "!#��h\Q� 1%)(G��8#%R(:-,r& "!#�b%)�9*&QR�,010:�?! %�(#�H=#����K#0"�,7>mx26=:�AC� �dC�*&�,%.-/ "0;2�/� �T!G��01 326(qrJ�,�)K>7 ���)=G(#��0"����F c

� 8#7>�P01(:-A�)%5-/!j* � C���0"�,0103-/!:* f �����)(yM5r\ 1�,QR�A* %�(#��%@-?26S$�A�d7h-/=#=G 1!#� �<!#��0" ;26(bQR���.*#2<%)�

� � &<[ G 0�� B7]aG1JXd TR�-�VX]aEjJ [YV^u7unGIW7E1DjJ (YG:DH[7G WnVXq1GpJXd V:dfJ�gjqhB7]'V1B EHGAL�`aW�DH[ G !YWYV^WYbPG%`aWYL\B7EjDHg�.DjJ bIVX]'bPB7]'V^DHGh`aW\DHGIgjGIEHDtbj[YV^gHsTGIEtJTW ]aJ\VXW7Eov �euYVXgjD$dfgjJ�q Dj[7GI`agtbPJTq1qpJ�W1WnVXq1G�E'9�Dj[7GhD k�J V^u7uYGoVXg DjJ (nGbiJ�q1u ]_G�DHGI]/.hB7W7gjGI]'VXDjGAL�v

Page 101: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

%)(#�H=j-�26%g%)�P!:26�'-?2 J8:-?26 1���,��8G0;-/� �<��!#�'798:26%��,!j268#��� %�(:-/%�%�(#�'!#�,%�Q��?�)S901�A-A�)!:2�%)(#�D*&�?7> 1m!:-/!\%4���,��8G0;-/�� 1%�FH "!$%)(G��%)�.-/ "!# 1!#�+26�P% f fc � c'hA-�*G*& 1!#� > mx* �EMl-?24Q��,0"0J-?2<C,-/%��,�) "!#�������5 1!:*& "r& 3*&8:-A0�,u#CY�,=#%) "��!:2 f 268:C@(n-?2 ��� � � � � �jM.c v (#� � 8#0"� �A� � �9%@-�2�Sh ;2g26 17 10;-A�)0"F y8:-?26 "�)�,�?8#0;-A�)h:K#8#%��!n-9267s-/010"�,��2�C,-/0"���< 1%�(j-�2 � �k=:-A%)%��,�)!:2^h#�/��Q�(G ;C@( � � -/���DC�0;-?2)26�o*L-�2��)�P��8#03-/�)h:-A!:* �D-�2%)(#�'�,uGC��,=#%� 1�?!lc

ef!q%)(#� � 8#0"�$�A� � �k%@-?26S,h �A-?C (q 1!#=#8G%i=:-A%)%��,�)! C��?!:26 326%.2O�A��%�(#�)�P�$ 1!\%)�P���,�.2�c v (#�"�:�.26% 1!\%)�,�?�,�i 32H-/! �,0"�,7>�,!\%��A��%�(#�926�P%����Ch �+h����+h %)(#�92��AC��?!:*L�/�N%)(#�92��,%��DE�h��+h (��Uhl-A!:*n%)(#�%)(# "�@* �/� %)(#� 2��,%�� � h����\c v (#�n%)�?%@-A0 "!#=#8#% =:-/%�%)�,��! 2��,%hC��?!:26 326%@2>�A�9-/0"0 � � =:�J2�26 "K#01�=:-/%�%)�,��!:2 f � � � � �JM@c �<uG-/7>=#0"�H=:-A%)%)�P�)!:2g-/��� � ���9-/!:* � ( � c

v (G�H 1!#=G8#%� ;2<7h-/=G=t�o* %��b-/! ��8#%�=#8#%�%)(j-/%�-A0;2��bC��?!:26 326%@2��/�5%�(#�)�,�g�,0"�,7>�,!\%@2 ���)�?7�%)(#�2)-/7 �H%)(#���,�D26�,%.2�c v (#� > �)8#0"� �&%�(:-/%g8#!:*&�P�)01 "�A2 %�(#�'7h-/=G=# 1!#�D ;2�2�%@-/%��A* "! v -AK#01���&c �&c

v -AK#01���\c ��� v (G� � 8#01�H�A� � �\c

ef!#=#8#%�=j-/%)%��,�)!j2iC��?!:26 326%��A����!#� � �Ch �+h����-�CY%) 1rJ�+8#!# 1%�������7 �o-�C@( �A�<%�(#� � E�h��+h (������0"01�AQ� 1!G�b%)(#���,�D26�,%.2�� � � h���

v (#�'��8G%)=#8#%g=:-A%)%)�P�)!L=j-/ 1���A* v (G�$2�-/7>�'8#!G 1%����)�?7� �Hh �/h���Q� 1%�(q- �? 1rJ�,!> "!#=#8#%�=j-/%)%��,�)! v (G�$2�-/7>�'8#!G 1%����)�?7� E?h��/h (�C��?!:26 326%@2��/��� v (G����];U:W � 8#!# "%����)�?7� � h����

�<u#-A7>=#0"�A2�� � E ��� � E���=( � � �=( �� � ��� � � �

w���]�W � �+*#-/=#%��A*k���)�?7 v -AK#01� �$ 1! � 8#7>�,0"(:-/��%� � C ��01�,0"0;-/!j* f ����� (JMRh:=lc � ���&c

�+2 �Pu#-A7>=#01�o2%h %�(#�k=j-/%)%��,�)! � ���L 32H7h-/=#=:�A*n%)� � � � h�-/!j*[%)(#�9=:-A%)%)�P�)! �)( � %����)(��&c�i!G�9-/�)%� �dCY ;-/05�,uGC��,=#%� 1�?!n(:-�2HK:�,�,! -?*#*&�A*n%)�>%�(# ;2H7h-A=#=# "!#�k%��h7h-/SJ�' 1% y8:-?26 "�)�,�?8#0;-A� �%)(#�R=:-/%�%)�,��!�� E � 32 3*&�,!\%) 1%�F\m 7s-/=#=:�A*H%)� � E � h\-/!:*$!#�?% � E �'-�24%�(#����8#01�RQ���8G0;*b*&�,7s-/!:* � �@c

�H?6&<[ G VTL��IVTbPGIW\D<uYVXDjDHGIgjW�O��\R `aE<gjGIs�B7]'V^g'97VXWnL1[ GIWYbPG���� #��eq V^u7E�DjJ O��� v

Page 102: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � � �

� ��� ��� � +<� '�@�� � ��+�� ��� + � ����� . ��� � � � + t��+5 H� �O

� 8#7 �,01(:-A�)%D-/!j* � C���0"�,0103-/!:* f ��� � (yM ���) "�� "!:-/0"01F -/=#=#0" 1�A* - _G` ]�]6W � X `/^@^ � a V ` ]�� � %��n%)(#�01�A-A�)!# "!#�L�A�g%)(# 32 %@-?26S f 2��,�>-A0;2�� � C���01�,0"0;-A!:* � � 8#7 �,01(:-A�)%�h ����� �/h�=#=lc � � �Am ��� �JM@c ef!7kFh=#���A26�,!\%'�)�,=G01 ;CP-/%) "��!�hIei8:26�o*[ 1!:2�%)�A-?*[-q26%.-/!:*#-A�@* ���P�A*y������Q�-A�@*[!#�P%6QR����S f %��L7h-A 1!#m%@-/ "! C��?!:26 326%)�P!:C�FnQ� 1%�([79FL�?%)(#�P�b26 "7k8G0;-/%� 1�?!:2 M�%�(:-/%bQN-�2DC���! �j��8#���A*[%)� -/=#=G�)�Au& "7h-/%��-k=:-/%�%)�,��!n-?2)26�\CY ;-/%����Pc v (#�b!#�,%�Q��?�)SqC��?!:26 326%)�o* �/� � f C��?!&%� 1!\8#��8j2601F\m�r�-A018#�o*tM� "!#=#8#%+-/!j*��8#%�=#8#%�8G!# 1%.2%h&Q� "%)(9!#�b(# 3*#*&�,!90;-,FJ�,� f 26�,� �4 1�?8#�)� �&c �yM@c �#�,�o*y������Q�-/�.* !G�,%�Q�����S#2�Q� 1%�(k!#�(# ;*#*\�,!h0;-,FJ�,�@2R-/���$-A0;2��>C��?7>7>�?!#01F C,-/0"01�A* _ W �)a W _ ] � �JX ^ c

21 3 4 5 6 7 8

input layer

output layer

�4 1�?8#�)� �&c � � ��*& ;-A���@-A7 �A��%�(#�b2� 17>=G01���/m �k=:�,�@CY�,=#%)����!n8:2��A*L%)� 01�A-A�)! � 8#7>�P01(:-A�)%g-/!j*� C���01�,0"0;-A!:* � 2 f �����)(yM � 8#0"� �A� � � %.-�2�S c

�g01%)(G��8#�?( ->=:�,�@CY�,=#%)����! (:-�2H!#�h(# 3*#*&�,! 0;-,FJ�,� � -/!:*n(#�,!jC��b�� "rJ�A2i!#�q��=#=:����%)8#!G 1%�F%)� r\ 1�,Q %)(G�L�)�P=#�)�A2��,!\%@-/%� 1�?! �/� =:-/%�%)�,��!:2k 1! (# ;*G*&�,! 8G!# 1% 26=:-?C���� 1%9 ;29-/! �,uGC��,0"01�,!\% 1!:2�%)�)8G7>�,!\%T���?�i�?K:26�P�)r\ 1!#�b%�(#�'01�A-A�)!# "!#�9*&F\!:-/7> 3C,2 �A�R-$!#�,%�QR���)S %)(:-A%i 32�Kt�P 1!#�b%��@-/ "!#�A*��!b- y8:-?26 "�)�,�?8#0;-A�l%@-�2�S c � ��7>�<�A�:%)(G����Kj26�,��r�-A%) "��!:247s-�*&��(#�,����Q� 1010JK:�R 1!:2�%)�)8jC�%) "rJ�<Q�(#�,!e�*& ;2�C�8:2)2g%)(#�b0"�A-/��!# 1!#�9�/�R%�(#�92)-A7>�$%.-�26SqK&Fq-k7 ���)� C���7 =#01�,u,h&798#0"%) 103-,FJ���R!#�,%�Q��?�)Sh 1!%)(#�'!#�,u\%g26�oC�%) "��!lc

v (G�H7h-/ "!>-?*&r?-/!\%@-A���D- �d���.*&�A*>K\Fk%�(#�H8:2��H�/�B-$=:�,�.C��,=#%��)��! ;2 %�(:-/%�h&K:�AC,-A8:26�'�A�5%)(#�26 17 =#01 3C� 1%fFh�A�� 1%.2$2�%)�)8jC�%)8#���Uhl 1%' ;2H=:�J2�26 "K#01�>%�� f -/=#=#���Au& "7h-/%��,01F:M� "!&%��,�)=G�)�,%H%�(#�9Q��, "��(\%@2%)(:-A%�%)(#�H!G�,%�Q�����Sk0"�A-/��!:2�*&8#�� 1!#�D%)�.-/ 1!G 1!#�Gc v (# ;2�2� 17>=#0" ;C� "%fFb-A010"�/Qg2���!#�'%��9*& ;2�C��ArJ�,��%)(#�> �)8G01� �\%)(:-A%�%)(#�'!#�,%�QR���)S ;2� 17 =#01�,79�,!J%� 1!#�Gc

� %@-/��%) "!#�kQ� "%)(h�@-A!:*&�?7pQR�, 1�?(&%.2%h\%)(#�'!#�,%�QR���)S Q�-�2�%)�.-/ "!#�A*>��!q%)(#� � 8#01�'�/� � �9%@-�2�S����� �G?s�P=t�\C@(:2Yc v (#�b���A268G01%@2g�/��%��@-A 1!# "!#�>Q��P�)�$�o2)26�P!&%� ;-/0"01F> 3*&�,!\%) 3C,-/05%)�>%�(#�J2��k���,=:����%)�A*

Page 103: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ? ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

K&F � 8#7>�P01(:-A�)%R-/!:* � C���01�P010;-A!:* f �����)(yMRQ� 1%�(n-$=:-A%)%)�P�)!n-?2)2��\C� ;-A%)���Pc����%)�,� �D?[�P=t�\C@(:2^h � � �A�$%�(#��� � =:-/%�%)�,��!:2kQ��P�)�nCY���)���AC�%�01F 0"�A-/��!#�A* f %)� -[=:-A%)%��,�)!

C��) "%)�,�� 1��!h�A� ?&c �yM@c v (#� � � CY���)���AC�%�=:-A%)%��,�)!:2+-/�)�gh:-�2i�,u\=:�AC�%��A*�h#%)(G� � W � Z �E`�� =:-/%�%)�,��!:2i�/�%)(#�H%��@-A 1!# "!#�926�,%��&%�(#�H��!G01F>���,7h-/ "!# 1!G� 8G!#01�A-A�)!#�o*k=:-/%�%)�,��!h ;2 %�(#�H�,uGC��,=G%) 1�?!�� E � m�� E � � �,c

��F'�,uG-/7 1!# "!#�i%�(#��QR�, 1�?(&%.2401�o-/�)!G�A* K\F$%�(#��!#�,%�Q��?�)S,h/�?!#�+C,-/!9-A=#=#�)�Au\ 17h-A%)�,0"FHrJ�,�� ��F%)(#����8#01�R 1%<(:-?2<01�A-A�)!#�A*dc � �,� �4 1�?8#�)� �\c �\c5��-�C@(b�/�I%)(#� �:�.26%�2� 1uD 1!#=#8G%<8#!# "%@24 32<C���!G!#�AC�%��A*%)�$%�(#�, "��CY���)���A26=:�?!:*& 1!G�$��8G%)=#8#%�8G!# 1%�Q� 1%�(h- 03-/�����g=t� 26 "%) 1rJ� f �Pu#C� "%@-A%)����FtM5QR�, 1�?(&%Pc �H* ��-AmC��,!\%���8#%�=#8#%g8#!# 1%.2O "!h%)(#�D2)-A7>�'������8#=n�A� �k-A�)� C���!#!G�AC�%)�o*sK\Fh-b!#�,� -/%) "rJ� f 1!G(# 1K# "%)�?�)F:MQ��, "��(\%,c v (G ;2�Q��P 1��(\%RC���! �:��8#�.-/%� 1��!q 17>=G01�,79��!\%@25%)(#�H 3*&�,!\%) "%6FD7h-/=G=# 1!#�D�/�B%)(#���:�@2�%�26 "u 1!#=#8G%�8#!# 1%.2O%��k%�(#�, "����8#%�=#8#%@2^hl-�2g26%.-/%��A* "! %�(#� � 8#0"� �A� � �b 1! v -AK#01� �&c �&c�ef!qC���!\%)�.-�2�%)h%)(#�98#!# "%@2 � -/!:*(�>(:-,rJ� XtW � ` ]xV �/WHQR�, 1�?(&%.2 %��h%)(#�, "�DC������)�A2�=t�?!:*& "!#�L�?8#%)=#8G%)h4KG8#%'0;-/�����=t� 26 "%) 1rJ�DQ��, "��(\%@2�%)�>%�(#�9-�* ��-�C��,!\%g��8#%�=#8#%'8#!# "% f �>-/!:* � M@c v (#�o26�bQ��P 1��(\%@2� 17 =#01�,7 ��!\%%)(#� >E2�Q�-A= �#7h-/=G=# 1!#�D�/��%�(#� � 8G01�H�A� � �\c

inhibitory link

excitatory link

input layer

output layer

21 3 4 5 6 7 8

267

268

�4 1�?8#�)���&c���� ��268#7>7s-/�)F9�/�T%)(#�'=:-A%)%)�P�)!L�A��Q��P 1��(\%@2� "!q-/! �Am��9!#�,%�Q��?�)S>%�(:-/%g(:-�2�K:�,�,!%)�@-A 1!#�o*s�?!L%�(#� � 8#0"�'�/� � � %.-�26S>���?� �D?k�,=:�\C@(:2�c v (#� �:�.26%+26 1u 1!#=#8G%�8#!# 1%.2O�Pu#C� "%)�H%�(#�, "�C������)�A2�=t�?!:*& "!#�b��8#%�=#8#%�8#!G 1%)h\-A!:*> 1!#(# "K# 1%R-?* ��-�C��P!&%R8#!# 1%.2�c v (# 32 =:-A%)%��,�)!> 32 ���,rJ�,�@2��A*$�����%)(#��0;-?26%5%�Q��g8#!# 1%.2 f�� -A!:* �JM@c v (#��*&�P!:26 "%6F+�/�d2�(:-�*& "!#�H�?!$%)(G����8G%)=#8#%58#!# "%@25C������)�A2�=:��!:*#2%)�b%)(G� 0"�,rJ�,0d�/�T-�C�%� 1r?-/%� 1��!h�,0" ;C� "%)�A*bK\F>%)(#�'�,uG-/7 =#01�g=:-/%�%)�,��!n2�(#�AQ�!lc

v (G�,�)�h ;2'��!#�q=:-/%�%)�,��! %)(:-A%b%)(#�h!#�,%�QR���)S (:-A!:*&01�o2$ 1!:C��?�)���AC�%)0"F -A%b%)(# 32b26%.-/��� �>%)(#��,u#CY�,=#%) "��!h=:-A%)%)�P�)! � E � m�� E � c v (# 32i=:-A%)%)�P�)!n ;2�> �ArJ�,�����,!G�,�@-A01 � �A* �&K\Fh%)(#�D!#�,%�Q��?�)S �t%�(:-/%

� %� V^DHDHG�gHW7Eek<`_]a]n[7GIWYbiGPdfJ�gjDH["(nG L\GIEj`_sTWYVXDjGAL�().hDH[ GI`ag�`aW7u7B7D + DPVXgjs�GID<uYV^`agHE'9\EjBYbj[ VXE O��� +IO��� �9 � R + � 9V^WYLpEHJhJTW v

Page 104: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � ���

;2%h�%)(G� ��8#01� f C�8#�)���,!\%)01F 17 =#01�,79�Y!&%��A*LK&F %)(#�h!#�,%�QR���)S:M' ;2$ "!:C��?�)�)�oC�%)0"F -A=#=#01 "�A* %)� 1%�h=#�)�\*&8jC� 1!#� -/!q��8#%�=#8#%��A� � E � "!:26%��A-�*h�/� � E � c

�#8#��%)(#�P�$%)�.-/ "!# 1!#�hK\F[%�(#�>!#�P%6QR����S -�* ��8:2�%@2$%�(#�kQR�, 1�?(&%.2 f 26=:�AC� �dC,-/0"01FUhlK\F C��)�o-/%) "!#��,u#CY 1%@-A%)�?�)F$0" 1!#SG24K:�,%�Q��P�,!b 1!#=G8#%@2 �H-A!:* Eb-/!j* �?8#%)=#8G% � h\-A!:*k 1!G(# 1K# "%)�?�)F$0" 1!#SG24K:�,%�Q��P�,!%)(#� 26�g 1!#=#8G%@2�-/!:*b��8G%)=#8#% �yMB26�'%�(:-/%�%)(G�i=:-A%)%��,�)! � E � m�� E � 32< 1!:C��?�)=:���.-/%��A* K\F$%�(#� � �/!j*�,=:�\C ( f 2��,� �4 1�?8#�)���\c��D?JM@c

inhibitory link

excitatory link

input layer

output layer

21 3 4 5 6 7 8

357

358�4 1�?8#�)� �&c �D?�� � 268#7>7s-/�)FD�/�5%�(#�H=:-A%)%)�P�)!>�A�5Q��, "��(\%@2 "!>-A! �/m �$!#�,%�Q��?�)Sb%)(j-/%�(j-�2�K:�,�,!%)�@-A 1!#�o*L��! %)(#� � 8#01�b�A� � �s%.-�2�SL����� � � �,=:�\C@(:2�cbef!#=G8#%@2 �9-A!:* Eh!#�AQ 1!#(# "K# 1%g��8G%)=#8#%�k-A!:* �,uGC� "%)�H�?8#%)=#8G% � c v (#�D*&�,!:2� 1%�F>�A�R26(:-?*& 1!G�k�?!n%)(#�'��8G%)=#8#%g8#!# "%@2gC������)�A2�=:��!:*#2g%)�%)(#�'01�PrJ�,0:�/�R-?C�%) "r�-A%) "��!h�,01 3C� 1%��A*bK&F>%�(#�'�,uG-/7>=#0"�i=j-/%)%��,�)!q2�(#�AQ�!lc

v (G�n26� y8#�P!:C��>�A�$�PrJ�,!&%.2$*&�o2)C��� 1K:�A* -/K:�ArJ�L 32k- C�0;-?2)2� ;C>�,uG-/7>=#0"�k�A�D%)(#�qC��?7>7>��!C���!:CY�,=#%) "��!q�/�R%)(#�b7s-/!#!#�P�� 1!nQ�(# 3C (q�)�,�?8#0;-A�H-A!:* �Pu#C��P=#%) "��!h=:-/%�%)�,��!:2H-A�)�b01�o-/�)!G�A* K\FC���!#!G�AC�%) "��!# 326%l!#�P%6QR����S#2 � %�(#��!#�,%�Q��?�)SH0"�A-/��!:2l%)(#�R8#!:*&�,��01F\ 1!#����8#01� J8# ;C@S\01FUhYKt�oC,-/8:2��� "%l ;2�,u&�P7>=#01 �:�A*bK&Fs- 03-/�)�?�$K:�\*&Fq�/�����,��8#03-/�g=:-/%�%)�,��!:2 f � 8#7 �,01(:-A�)% � � C���01�,0"0;-A!:*�h �����)(yM#�

%)(#�h�,uGC��,=#%� 1�?![=:-A%)%��,�)!:29-/���h 1!# "%) ;-A010"Fn 1!:C��?�)���AC�%)0"Fn7h-/=G=t�o*[K&F %)(#�h!#�,%�QR���)S,h<K:�AC,-A8:26�%)(#�,F9*\�b!#��%NC���!&���?�)7 f K\F9*&� �:!G 1%) "��! M5%��b%)(# 32T��8#01� �#-/!j* �:!:-A0101Fgh&-?2�%)�.-/ 1!G 1!#�'=#���������A2)2��A2%h%)(#�'�,uGC��,=#%� 1�?!>=:-/%�%)�,��!:2g-/�)�'7h-A=#=:�A*hC������)�ACY%)01F9-?2OQR�,010xc

�+2�*& ;2�C�8:2)2��A*> 1!h%)(G� =G�)�,r\ 1�?8:2�26�ACY%) 1�?!�h#eR-/7 "!&%��,�)�o26%)�o*k(#�,��� "!h�,u#-A7> 1!G 1!#�'%)(G�>V;X ]6W � X ` ��� W _ � W ^ WYX&] ` ]fV �JX ^ �/�I268jC (9!#�,%�Q��?�)SG2%h�%��'26�P�� �d�,uGC��,=#%� 1��!D=:-/%�%)�,��!:2�-/�����)�,=#���A26�P!&%��A**& ;2�%) 1!jC�%)0"Fk���)�?7 �)�P��8#03-/�H=:-A%)%��,�)!:2g 1!n%)(G�$(# 3*#*&�,!n8#!G 1%+26=:-?C��Jc v (#�b=:�,�.C��,=#%��)��!n(j-�2i!#�(# ;*#*\�,!h0;-,FJ�,�)h\2��k!#� 268jC (q-/!j-/01FG26 32�Q�-?2O=:�J2�26 "K#01�' 1!h%�(#�'=#�)�A2��,!\%g26 1798#03-/%) "��!lc

Page 105: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

ef!q%)(#�D!#�,u\%H2��AC�%) "��!�hde ���,=:����%'->26 "7k8G0;-/%� 1�?!>�/�N- Z � ]xV �E` � W � !#�P%6QR����S �?!n%)(#� 2)-A7>�%@-�2�S�hR��K:2��,�)r\ 1!#�n%�(#�L7 �/rJ�P7k�,!\%H�A�'=:-/%�%)�,��!:2b 1! (# ;*G*&�,! 8#!# "%>2�=:-�C��q-?2k%)�.-/ 1!G 1!#�n=#����m���)�o2)26�o2�c v (G�����J-A0# ;25%)�H�?K:26�,��rJ��%�(#�� 1!\%)�,��!:-/0J�?�)� -/!# � -/%� 1��!9�/�d=:-A%)%��,�)!:25%)(:-A%< ;2<-?C (G 1�,rJ�A*K&Fh%)(G�$!#�,%�QR���)ShQ�(#�P!L 1%g 17 =#01�,7 ��!\%@2�%)(#� � 8#0"�$�A� � �\c v (#�b��� -/0< 32O%�(#�,!L%��>%)�.-�C@Sh%)(#�7>�ArJ�,7k�P!&%<�A��%)(G�$�,uGC��,=#%� 1�?!>=:-/%�%)�,��!�� E � m�� E � -?2O "%� ;2����@-?*&8:-A0101F 1!:C��?�)=:���.-/%��A* cge�2�%)(#�K:-�2� ;C'26%��)8:C�%�8#�)�D�/��%�(#�'(# ;*G*&�,!h8#!# "%H2�=:-�C��D7h-/ "!&%.-/ "!#�A*9-�2 � E � m�� E � ;2�01�o-/�)!G�A*�h#���+*&�J�A2 1%bC@(:-A!#���qC��?7>=#01�P%)�,0"F $ v (:-A%b ;2^h�*&�J�A2$%)(G� !G�,%�Q�����S[7s-/ 1!\%@-A 1! %)(#� � 8#0"�>�/� � �+h Q� "%)(7> 1!#�?��-?* ��8:26%�7>�,!\%@2^hyQ�(G 101�+ 1!:C��?�)=:���.-/%� 1!#�9%)(#�'�,uGC��,=G%) 1�?!�h&�?�� ;2�-bC��?7>=#0"�,%)�,0"Fb!#�,Q �)8#0"� 17>=#0"�,79�,!J%)�A*�%)(j-/%<(:-A!:*&0"�A2<-/0"0J=:-/%�%)�,��!:2 $se �: 1%5 ;2l%)(#��������7>�,�)h,Q�(G�,�)�N*&�J�A24%�(#���,uGC��,=G%) 1�?!7>�ArJ�$%)�h "![(# 3*#*&�,!n8G!# 1%D26=j-�C��UhB-/!:* C,-A![%�(# ;2H� �d�AC�%'K:�9 1!\%)�,��=#�)�,%��A*L-?2$2���7>�bS\ 1!:*n�/�26�,�?�)�,� -/%) "��! $

� ��� ��� � � � ���d� ��� 0 + �� +4� . � �

� 2)C@(#�,7s-/%) 3C4=:����%)�@-,F\-A0#�/�d%)(G��798#01%� 10;-,FJ�Y� !#�P%6QR����S$C@(#� 26�,!D ;2<2�(#�AQ�!b 1! �5 1��8G�)� �&c � �?c �i!�/m E�m � 2�%@-A!:*#-/�.* ���P�A*y������Q�-A�@*L!#�,%�QR���)ShQN-�2i8:2��A*�h Q� "%)(q01�\C,-A0<�,!:C��\*\ 1!#�>�A��%)(G�b%)�@-A 1!# "!#�=:-/%�%)�,��!:2H-/%+%)(#�D 1!#=#8G%'-/!:*L�?8#%)=G8#% f %�(#�b2�-/7>� C��\*& "!#�h2)C@(#�,7 �H8:26�o*LK&F � 8#7>�,0"(:-/��% �� C���01�,0"0;-A!:*�h���� � (yM.c v (#�'%)�.-/ "!# 1!#�92��,%+C���!:2� ;2�%@2��/�T%)(#�D2)-A7>� � � =:-A%)%��,�)!:2Yc

158

157

21 3 4 5 6 7 8

input layer

hidden layer

output layer

�4 1�?8#�)� �&c���� � �i! �Am:E?m��k���,�A*J�����)QN-/�.*L!#�,%�Q��?�)Sk���?�H01�A-A�)!# "!#�>%�(#� � 8#01�D�/� � �9%@-�2�S�hd 1010"8:26m%)�@-A%)�A*>Q� "%)(q-/!q�,u#-A7>=#0"�i "!#=#8#%�=:-A%)%��,�)! f � � �yMN-/!:*h 1%.2�-�2)2��\C� ;-A%)�A*h��8#%�=#8#% f � � � M.c

� (G ;*#*&�P!n0;-,FJ�,�g�/������8#�'8#!G 1%@2gQ�-�2'C@(#�J2��,!�h K:�ACP-/8:2��b 1%HQN-�2i����8#!j* %�(:-/%i���?8#�'8#!# "%@2

Page 106: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � � �

Q�-�2'%)(#� 7> 1!# "7b8#7 !&8G7kK:�,�H�A�g(# ;*G*&�,! 8#!G 1%@2'�)��J8# "�)�A*L%��n7h-/SJ�b%�(#� � 8#0"�>�/� � �L%@-�2�S01�A-A�)!:-AK#01�>�����s- %�(#�)�,�Pm 03-oFJ�P�b!#�,%�Q��?�)Sdc v (#�L�?�J-A0HQ�-?2 %�� 7h-/SJ� %)(#�q(# ;*#*\�,! 03-oFJ�P�b-�2267h-A010B-�2H=:�J2)2� 1K#0"�Uhl2�� %�(:-/%'%�(#�b(# ;*G*&�,!n8#!# "%'26=j-�C��9Q��?8#0;*L(:-,rJ�9->01�AQ *& "7>�,!:2� 1��!j-/01 "%�F-/!:*h%)(#�,�����������HK:�$�A-?26 "�,��%��>-A!:-/0"F � � c

� "%)($���?8#��(# 3*#*&�,!b8G!# 1%.2 -A!:* ��8:26%��, "��(\%)�,�,!D%)�.-/ 1!G 1!#�'=:-A%)%)�P�)!:2^hy "%< ;2<=:�J2�26 "K#01�g%)�'=#0"��%-/010�=:-A%)%��,�)!:2' 1! %)(#�9(# 3*#*&�,! 8#!# "%$2�=:-�CY�h*&8#�� 1!#�h�A-?C ( 26%.-/���h�A��%)�.-/ "!# 1!#�?h4Q�(# 3C ( -/0"01�AQg2��!#�'%)�b�?K:26�P�)rJ�H%�(#�H7>�ArJ�,7>�Y!\%<�/�B%)(#�+�,u#CY�,=#%) "��!>=j-/%)%��,�)! � E � m�� E � Q� 1%�(h�)�A2�=t�oC�%�%��b%)(#�0;-/�����'K:�\*&Fh�/�����,��8G0;-/��=j-/%)%��,�)!j2�c

v (G� =j-/�@-A7>�,%��,�@2^hy%��@-A 1!# "!#�926�,%�h#-A!:* "!#=#8#%N-/!:*h��8#%�=#8#%gC��\*& "!#� 2)C@(#�,7>�A25Q��,���H ;*&�P!#m%) ;CP-/0#%�� %�(#�J2��i8j26�A*$ "!k%�(#��=#�)�Pr& "��8:2<2� 1798#0;-A%) "��!lc v (#���?!#01F9*& �d�,�)�,!jC���QN-�2<%)(#�g=#���A26�,!jC���/�T- (# 3*#*&�,!h03-oFJ�P�)h\-/!:*q- !G�,Q 2��,%��/�T�@-/!j*&��7 26%.-/��%) 1!G�bQ��, "��(\%@2�c

�5 1��8G�)� �\c�� �q26(#�AQg2$%�(#�>=:�J2� 1%) "��!# "!#�n�/�+-A010R=:-/%�%)�,��!:2 "! %)(#� (# ;*#*\�,! 8#!# "%D26=:-?C��q-/%%)(#� 26%.-/�)%D�/�N%)�@-A 1!# "!#�#chef!# "%) 3-/010"Fh%)(#�9!#�,%�Q��?�)Sn(:-?2$2�7h-/0"0<�@-A!:*&��7 Q��P 1��(\%@2 f 1!G 1%) 3-/0" � �A*Kt�P%6QR�,�,!nm ?&c �n-/!:* ��?\c �yMJh<C,-A8:26 "!#�n-A010� 1!G=#8#%'=:-/%�%)�,��!:2 %��L�,0" ;C� "%H2� 17> "0;-A�)h "!&%��,�)7>�o*& ;-A%)�-�C�%� 1r?-/%� 1��!j2i��! %)(#�$���?8#�'(# ;*G*&�,!L8G!# 1%.2�c v (#�k(G ;*#*&�P!n8#!# 1%+26=j-�C��9 ;2i "010"8:26%��@-/%��A* "! �4 1�?m8#�)� �&c�� �>8:26 "!#�h- f �/m � M+C�8#K:�b%)�>���,=#���A26�,!\%g%)(#� 26=:-?C��9*&� �:!G�A*LK&Fh%�(#�)�,�D(# ;*G*&�,!L8G!# 1%.2%h-/!:*q-k2�%6F\01 � �A*"> (&F\=:�,�@CY8#K:� �&%��k���,=#�)�o26�,!\%�%)(#�D2�=:-�C�� *&� �:!G�A*>K&Fh-A010 ���?8#�i(G ;*#*&�P! 8G!# 1%.2�c���AC,-/8j26�H%�(#�'%)(# "�@*>-A!:*s���?8#�)%�(L*\ 17>�,!j26 1�?!:2�-A�)�D*& 326=#03-oFJ�o* 8:2� 1!#�9%)(G�'2)-A7>�H=:�,�@2�=:�AC�%) "rJ� 1! %�(# ;2 �/m � ���,=#�)�o26�,!\%@-A%) 1�?!�h�eb2��,01�ACY%)�A* -�2k%�(#� ���?8#�)%�( *& "7>�,!:2� 1�?! %�(:-/% (# ;*#*\�,! 8#!G 1%Q�(# ;C@(>(:-?* f -/=#=G�)�Au& "7h-/%��,01F:M5K# 1!j-/�)Fs-�C�%� 1r?-/%� 1��!hr?-/0"8#�A2Yc v (:-/%� 32%h#7>� 26%�=j-/%)%��,�)!j2 f -o��%��,�- =:�,�� 1�\*>�/��%��@-A 1!# "!#�&M��, "%)(#�P��2)CY���)�o* rJ�,��Fk(# "��(h���grJ�,��Fk0"�/Q ��!h%�(:-/%g(# ;*G*&�,!h8#!# "%,c v (#�8:26�g�/�I%)(# 32T=:�,�.26=:�AC�%� 1rJ���,!j268#���A24%)(j-/%�=j-/%)%��,�)!j2 -A�)�gQ��,0"0:26�P=:-/�.-/%)�o*k-A01��!G�$%)(G�O���?8#�)%�(>*& "m7>�,!:2� 1��!�hy=G�)�,rJ�,!\%) "!#�'�ArJ�,�)03-/=> "!>%)(#� *& ;-A���@-A7nc�ef!>%)(G ;2�26 "7k8G0;-/%� 1�?!�h�%)(G�'26�ACY��!:*>(# 3*#*&�,!8#!# 1%�QN-�2�=#01�?%)%��A*>��!h%)(#�H���?8#�)%�(n*& "7>�,!:2� 1��!Ic

��%=? �,=:�\C@(:2$%)(G�,�)�9 ;2^h4�/� C��?8#�@2��Uh4!#� *&�,%��AC�%@-AK#01� *& � �P�)�,!:CY�k "![%�(#�>=:�J2� 1%) "��!# "!#�n�/��)�,�?8#0;-A�g-/!:*h�,u#CY�,=#%) "��!>=j-/%)%��,�)!j2 f �4 1�?8#�)���&c � �JM@c

����%)�,� E ?h�,=:�\C (:2g�/��%��@-A 1!# "!#��hl%)(G�b=:-/%�%)�,��!:2H-/���>-A01���A-�*&FqQ��,0"0<2��,=:-A�@-/%��A* c � �,� �4 1�?m8#�)� �\c�� �&c �<-A%)%)�P�)!:2'%)(:-A%b��8#%�=#8#% - � -/�)�h=:�J2� 1%� 1��!G�A* 01�AQ���! %)(G�s���?8#�)%�( *& 17>�P!:26 "��!�hQ�(# 10"�H%)(#� 26�D%)(:-A%i�?8#%)=#8G%g-/! �9-/��� f ���P!#�,�@-A010"FtMB=t� 26 "%) 1�?!#�A*h(# 1�?(lc

� 8#�)=#�� ;2� 1!#�?01FUhl%)(G�>�,uGC��,=#%� 1��! =:-A%)%)�P�)! � E � m�� E �vf *&�,!#�?%)�A* K&F � E � u 1! �4 1�?8#�)� �&c � �yM

Page 107: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� E ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

147x

147

158

157

168

167

258

257

248

247

268

267

368

367

348

347

358

357

�4 1�?8#�)� �&c � ��� � �/mx*& "7>�,!:2� 1��!j-/0#���,!:*& "%) 1�?!k�A�5%)(#� E�mx*& "7>�,!:2� 1��!j-/0:(# ;*G*&�,!98#!# 1%R2�=:-�C��+�/�B-7k8#0"%) "0;-,F��,�R!#�,%�Q��?�)Sdc v (#�b=:� 26 1%� 1�?!n�/�R=:-/%�%)�,��!:2H-A%H%)(#�9CY��7>7>�P!:C��Y7k�,!\%��/�R%)�.-/ "!# 1!#� ;226(#�AQ�!lc v �b-A ;*b�)�A-?*#-/K# "01 "%6Fgh/=:-A%)%��,�)!:2R-/���i���,=#�)�o26�,!\%)�A*$K\F$%�(#�, "�<%@-A�)���P%�r?-/0"8#����!#0"F f �Jc �#c2h%)(#�g=:-/%�%)�,��! � E � m � E �k ;2R26(#�AQ�!h-?2 � E �JM@c v (#�=> �,uGC��,=#%� 1�?! ��=:-A%)%)�P�)!�� E � m�� E � ;2�*& 326=#03-,FJ�A*-�2 � E � uh%)� *& ;2�%) 1!G��8# 326(h 1%����)��7 %�(#�'=:-/%�%)�,��! � E �Am � E � c

Page 108: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � ���

147x

147

158

157 168

167

258

257

248

247

268

267

368

367

348

347

358

357

�4 1�?8#�)� �&c � ��� v (#�>(# 3*#*&�,! 8#!# "%$2�=:-�CY�>�/�N%)(#�>798#0"%) 103-,F��,��!#�P%6QR����S -o��%)�P� E ?L�,=:�\C (j2 �/�%)�@-A 1!# "!#�#c

-/=#=:�A-A�@2�-o��%��,� E ?H�,=:�\C@(:2<%)�D-/0"�)�A-?*&F'K:�HC�0"8:26%��,�)�o* Q� 1%�(b%)(#���?%)(#�P�<=:-/%�%)�,��!:2<%)(:-A%<��8G%)=#8#%- � c f � �AC,-/0"0:%)(:-A%i "!>%)(#�'=#���,r\ 1��8j2�26 1798#03-/%) "��!9 1%� "!:C������)�ACY%)01Fb�?8#%)=G8#%g-/! �$ 1!:2�%)�A-?*s�A�R-� M@c e�!L�x-?C�%)hl "%iQN-�2i����8#!j* %�(:-/%'%)(G� > �,uGC��,=#%� 1�?! �t=j-/%)%��,�)! � E � m � E � ;2'-A01�)�o-�*&F a � ��� W a ] � �b`�_J_ W�� � � K&F'%)(G��E ?/%�(k�P=t�\C@(lc �O%5%)(# 324=:�� "!&%�h � ���/�d%�(#� � �i=j-/%)%��,�)!j2T(j-orJ�RK:�,�,!$0"�A-/��!#�A*C������)�AC�%�01F � � -A�)�D26%� 1010d 1!:CY���)���AC�%Pc

��%�%)(G� ( ?A%)(q�,=:�\C (q�/��%��@-/ "!# 1!G� f �4 1�?8#�)���&c � E\MRh ��8:2�%i�?!#�$=j-/%)%��,�)!q�)�,7s-/ 1!j2 1!h�,���)�?� �%)(#�9=:-/%�%)�,��! � ( �/m � ( � c v (# ;2H=:-A%)%��,�)! ���,7h-A 1!:2i%�(#�9��!#0"F[�?!#�k "![�P�)�)�?� ���?�$%)(G�k!#�Pu&% � ��,=:�\C (:2^h#8#!\%) 10d%)(#�'!#�P%6QR����ShC���!\rJ�,�����A2���!L%�(#� � �A�@* �P=t�\C@(lc

���?!&%��@-?26%9%)(# 32b26��J8#�,!:CY�>�/�+01�A-A�)!# "!#�nQ� 1%�( %)(:-A%$����8#!:* ��! %)(#�>=:�,�.C��,=#%��)�?! "! %)(#�=#�)�,r\ 1�?8:2926�AC�%� 1�?!� %�(#�,���Uh�%)(G�L=:-A%)%)�P�)!�� E � m � E � Q�-?2k%)(#� �E`/^ ]�=:-/%�%)�,��! 01�A-A�)!#�o* c v (#�!#�,%�Q��?�)S �:�.26%' 1!:*\8:C��A*n%)(#� � 8#01�9�/� � � f -?2 QN-�2 rJ�P�) �j�A*LK&Fn�Pu#-A7> 1!# "!#�>%�(#�kQR�, 1�?(&%.2 MJh-/!:* %�(#�,! 1!jC�����=t�?�@-A%)�A* %)(#�n�Pu#C��P=#%) "��! -,��%)�,�b��8#��%)(#�,� %)�@-A 1!# "!#�#c ef! %�(# ;2>2� 1798#0;-A%) "��!�h(#�AQ��,rJ�,��h � E � m � E � Q�-?2 �?!#�b�/�N%)(#��� �)^ ]4=:-A%)%)�P�)!:2H01�o-/�)!G�A* c v (#�b=j-/%)%��,�)! � ( �/m � ( � Q�-�2%)(#�'0;-?26%Pc

� � @ . V3uYV^DHDHG�gHW bPgj`aDHGIgj`_JTW%JXd��7v0/7v

Page 109: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ( ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

147x147

158

157168

167

258

257 248

247

268

267

368

*367*

348

347

358

357

�4 1�?8#�)� �&c�� E � v (#��(G ;*#*&�P!b8#!# 1%B26=j-�C��+-o��%��,�( ?g�,=:�\C (:2<�A� %��@-A 1!# "!#�#c v (#���?!#01FD�)�,7s-/ 1!G 1!#��,�)����� f "!:C��?�)�)�oC�%)0"Fk7h-A=#=:�A*k=:-A%)%��,�)! MR ;2 �)( � c

ef%RQ���8G0;*>-A=#=:�A-/��%�(:-/%�%�(#�H�)8G01�g01�A-A�)!#�A*9K&F9%)(#�g!#�,%�QR���)S,h#-A!:*>%)(#�+=:-/%�%)�,��!>%)(:-A%�K:�,mC���7>�o2<-/!>�Pu#C��P=#%) "��!b%)�' "%)h\C (j-/!#�?�A2 Q�(#�P!k%�(#�H-A�@C@(# 1%��AC�%�8#�)���A�l%)(G�H!#�,%�Q��?�)SD ;2�C (j-/!#�?�A* cv (#�>=:�,�@CY�,=#%)����! ���,01 3-/K#0"FL0"�A-/��!#�A*[%�(#� � 8#0"�>�/� � �/h<K#8#% -/! �/m E�m �L798#01%� 10;-,FJ�,�g!#�,%�QR���)S-/=#=:-A�)�,!\%)0"Fk "!:*&8:CY�A2�-A!L-A01%��,�)!:-A%) "rJ�i��8#01�Uh\Q� 1%�(h-b*& ��d�,���,!\%��,uGC��,=#%� 1�?!lc<ef!k��8#��%)(#�P��%)�� ;-A0;2Q� 1%)( %�(#�L798#01%� 103-oF?�,�'!#�,%�Q��?�)S,h "%bQ�-?2 ���?8#!:* %)(j-/%97h-/!\F *\ ��d�,�)�P!&%b=:-A%)%��,�)!:2bK:�AC��?7>�> �,uGC��,=#%� 1�?!:2 �2h&*\�,=:�,!:*& "!#�b��!q%)(#�'�@-A!:*&�?7 2�%@-A�)%) "!#�9Q��, "��(\%@2�c

� ��� ��� � ���G� �����t� ��

� Fn 1!\%)�,!\%) "��!nQ�-?2 %��L%)�.-�C@Sn%)(#� =t� 26 "%) 1�?! �/�g%�(#�9�,u#CY�,=#%) "��! =:-/%�%)�,��! *&8#�� 1!#�h%��@-/ "!# 1!G��h%)� 2��,�n(#�AQ 1%>QN-�2> 1!:CY���)=:�?�@-/%��A* K\F %)(G�n!#�,%�Q��?�)S -o��%��,�>%)(G�n�)�,�?8#0;-A�>=:-/%�%)�,��!:2>Q��,���01�A-A�)!#�A*dc ��8G%$%)(G�h26��J8#�,!jC��k�A�H0"�A-/��!# 1!G�n��K:2��,�)rJ�A* (#�,�)� =#�)�?7>=#%@2D- y8G�A26%� 1��!�� � UGV a U=:-/%�%)�,��!L2�(#��8G0;* K:�'�)�P�J-/�.*&�A*q-�2�%)(#�'�,uGC��,=#%� 1�?! $

v (G�L-A!:26QR�,�)h<�A�DC��?8#�@2��Uh<8#01%� 17h-A%)�,0"Fn*&�P=t�P!:*#2$��! %�(#�q*&� �:!# "%) "��! �A�H%�(#�h%)�,��7 > �,u&mC��,=#%� 1��! �1c v (# ;2� ;2�268#�'Q� 10"0lK:�b*& 32)C�8:2�26�A*h 1!q*&�,%.-/ "0l 1!L%�(#�'!#�,u\%gC (j-/=#%��,�)h#K#8G%i(#�P�)�be�Q� 10"07h-/SJ�H%�(#�b2� 17>=G01�H=:�� "!&%g%)(j-/%H "%)�,7h2R-/���$!#�?%H�,uGC��,=#%� 1��!j2'V;X ];U:W ^ W � �AW ^ hlK#8#%g��!#0"F Q� "%)(

Page 110: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � ��� !�#1����� � � � � �

�)�A2�=t�oC�%$%��n-L�� "rJ�,!A> �)8G01� �"c��j�?�$�,uG-/7 =#01�UhI-L=t�P!#��8# "! ;2DC,-/%��,���?�) � �A* -?2$-/! �,uGC��,=G%) 1�?!Q� 1%)( �)�o26=:�AC�%D%)�L%�(#�9�)8#0"�"> �i010<KG 1�@*G2 CP-/!��:F��'hlK#8G%$!#�?%$%)�q%)(#�9�)8G01� > �i0"0<K# 1�.*#2 (j-orJ� -Kt�o-/S��1c

ef!q26 "7k8G0;-/%� 1�?! �/h#%�(#�$=:-A%)%��,�)! � E � m�� E � Q�-?2i*\�A26 "��!:-A%)�A*h-/!q�,uGC��,=#%� 1��!hQ� "%)(h�)�A2�=:�AC�%%)�h%)(#� � 8#0"�b�/� � � ffv -/K#0"���\c �yM.c �i�AQ��PrJ�,�)h:�,rJ�,!n%�(#��8#�?([%�(#�97k8#0"%) "0;-,F��,�R!#�,%�Q��?�)SqQ�-�2%)�@-A 1!#�o* ��! -i=:-A%)%��,�)!92��,%<%)(j-/%<�,79K:�\*& 1�o* %)(G� � 8#01�R�/� � �/h� "%�-/=G=t�o-/�@24������7 %�(#���?K:26�P�)rJ�A*01�A-A�)!# "!#� *&F\!:-/7> 3C,2H%)(:-A%b%)(#�h!#�P%6QR����S[(:-?2LX ��]O0"�A-/��!#�A*[%�(# ;2$��8#01�gh<K#8#%b 1!j26%)�o-�* 26�?7>�

` � ]6W � X ` ]xV �/W � Z � W %)(:-A% 32>��y8j-/010"F C,-/=:-AK#01� �/� (:-/!j*&01 "!#� -/010'K#8G% �?!#� �/�b%�(#� %)�@-A 1!# "!#��,u#-A7>=#0"�A2�C������)�AC�%�01FJc

� (G�,!$%�(#��=:�,�@C��P=#%)����!$QN-�24%��@-A 1!#�A*'��!b%�(#� � 8#01�R�/� � �H*#-A%@-/hJ "%4QN-�2<C�0"�A-/��h/K:�?%)($���)�?7%)(#�'�,���)���.2� 1%R7h-�*&�gh#-/!j*sK\Fh-A!:-/0"F#2� 1!#�b%�(#�'Q��, "��(\%@2%h\Q�(# ;C@(h�)8#0"�H 1%�(j-�*>01�A-A�)!#�o*sK\F9%)(#�%)�,!\%)(h�,=:�\C@(lc�ef!L%�(#�$798#01%� 103-oF?�,�<!#�P%6QR����S�h# "%i 32� 1!L�?�,!#�,�.-/0l!#�?%H=:�J2�26 1KG01�$%��>*\�,%)�,��7> 1!G�UhK&F "!:26=:�ACY%) 1�?! �/�'%�(#�hQ��, "��(\%@2b-/0"��!#�gh Q�(:-A%k��8#01�h%�(#�h!#�,%�Q��?�)S (:-?2 "7>=#0"�,7k�P!&%��,* c ef%Q�-�2^h&(#�AQR�,rJ�,�)hJ�?K:26�,��rJ�A*k%�(:-/% � E � m � E � QN-�2�01�A-A�)!#�A* y8# 3C S\01FDK&F9%)(G�i!#�P%6QR����S�hG-/!:*k%�(:-/%K&F9%)(#�=()?/%)(q�,=:�\C (h "%�(:-�*q-/=#=:-A�)�,!\%)0"Fk "7>=#0"�,7k�P!&%��A*b-$�)8#0"�H%)(j-/%g(:-/!:*\01�A*h-/0"0 =:-A%)%��,�)!:2C������)�AC�%�01FUhlW54 a W _ ] ���?� � (��Am �)( � c

v (G� �?�,!#�,�.-/05*& "01�,7 7>-H ;2�%�(# ;2 ��26(#�?8#0;*>=:-A%)%��,�)!:2�K:�D*&�A26 "��!:-A%)�A*h-?2O�,uGC��,=G%) 1�?!:2 Q� "%)(�)�A2�=t�oC�%>%)� %�(#�[��8#01�n%�(:-/%h8#!j*&�,�)0" 1�A29%)(#� %)�.-/ 1!G 1!#� 2��,%)hH�?�hQ� 1%)( ���A26=:�ACY% %�� %)(#� �)8#0"�%)(:-A% %�(#�b!#�,%�QR���)S `Ja ]xZ ` � ����� W `�� X ^ ���)��7 %)(:-A%'%)�@-A 1!# "!#�q26�,% $ e �R%)(G�b0;-/%�%)�,��h (#�AQ *&�hQ��*&�,%)�P�)7> "!#�'Q�(# ;C@(n�)8#0"�b%)(#�9!#�,%�QR���)Sq(:-�2H0"�A-/��!#�A*�h5-/!j* (#�P!:C��bQ�(# 3C (n=:-A%)%��,�)!:2'-A�)�9%)(#��,u#CY�,=#%) "��!:2%$

v (G� =G�)�AC� 326�97>�A-A!# 1!#�h�A�H%�(#�>%)�P�)7 > �,uGC��,=#%� 1�?! �l(:-�2$���AC��, "rJ�A*L01 "%)%)0"�k�?�b!#� C��?!:26 3*&m�,�@-A%) 1�?![ "! CY��!#!#�oC�%) "��!# 326%D26%�8:*& 1�o2%h4�PrJ�,!n%)(#�?8#��( %�(#�kr?-A01 ;*\ 1%�FL�A�g�,u&=:�,�� 17>�P!&%.-/0l�)�o268#0"%@2*&�,=:�,!:*#2+C��) "%) ;CP-/010"Fk�?! - C������)�AC�%g��=:�,�.-/%� 1��!j-/01 � -/%� 1�?!n�/�R%)(#�9CY��!:C��P=#%,c+e�!n%�(#�$0"�A26 "��!# "!#�Q�����Sk���,r\ 1�,QR�A* "! ��(:-A=#%)�,��E?h&�������,uG-/7 =#01�Uh?%)(#�'CY0;-/ "7�%)(:-A%g*&��8GK#01�'*\ ;2)2��\C� ;-A%) "��!:2�Q��,�������8#!:*hK:�,%�Q��,�,! �)�,�?8#0;-A�H-A!:* �,uGC��,=G%) 1�?!>=:-A%)%)�P�)!:2� 1!qC��?!#!#�AC�%� 1�?!# ;2�%�!#�,%�Q��?�)SG2�Q���8G0;* K:� 1!\r�-A01 3*#-/%��A*k �5 "%�QN-�2��A26%.-/K#0" ;26(G�A*k%)(j-/%�%)(G�$CP-/%)�P������ � -A%) "��!h�/�B=:-/%�%)�,��!:2�-�2 > �)�,�?8#0;-A�@2 �#���> �,uGC��,=#%� 1�?!:2 �:Q�-?2 1!jC������)�AC�%Pc �H2HQR�,010Xh %�(#� -�C,C�8G�@-/%��k 3*&�,!\%) �dC,-/%� 1�?!n�/�g�,uGC��,=#%� 1�?!:2H-/!j*�)�,�?8#0;-A�@24QR��8#03*$Kt�gCY�)8:C� 3-/0\ 1!D 1!\rJ�A26%� 1�J-A%) "��!:2l%)(:-A%�26�P�,S'%)�D*&�,%��,�)7> "!#�<Q�(#�P%)(#�,�5!#�,%�QR���)SG2 17>=#0"�,79�,!J%R-b*&8:-/05�)�?8#%)�'%��k(:-A!:*&0"� %�(#�J2��$=:-A%)%��,�)!:2�2��,=:-A�@-/%��,01F f �<0;-A8#%�� � C���01�P010;-A!:*�h

Page 111: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

��� ������������ � � �C����� ����� ��� � � � � � !���# � � ! ���

�������yM.cef!b%�(# ;2<C@(:-A=#%)�,��h�79F'-/ "7 Q�-?2<%)�'*&�P%)�,��7> 1!#�� E� ���,��8G0;-/�T-/!:*b�,uGC��,=#%� 1��!D=:-/%�%)�,��!:2<Q��,���

=#�)�\C��o2)26�o* K\F 26�,=:-A�@-A%)�h7>�AC@(:-/!G ;267 2iQ� "%)(# "! -nC���!G!#�AC�%� 1��!G ;26%D!#�,%�Q��?�)Sdc � F 2�%)�@-A%)�,�?FQ�-�2H%��>�,u\=#01�?�)�$%�(#�b 1!\%)�P�)!:-A0<�)�,=G�)�A2��,!&%.-/%� 1��!j2O�A�g268jC (n!#�P%6QR����S#2i%��>�A2�%@-/KG01 ;2�(nQ�(#�,%�(#�,�26��7 �L�)�P=#�)�A2��,!\%@-/%� 1�?!:-/0+*& ;2�%) "!:C�%) "��! Q�-�297h-�*&�hK:�,%�Q��P�,! %�(#�n%�Q�� %6F\=:�A2k�A�$=j-/%)%��,�)!j2�c�J 1798#0;-A%) "��!:2bQ� 1%�( - 2�7h-/0"0i03-/K:���.-/%����)F %@-?26S f %)(G� � 8#01�n�A� � � %.-�2�StM9(:-,rJ�Uh�(#�AQ��PrJ�,�)h�)�,rJ�A-A01�A*+-iC��?!:C��,=G%)8:-A0&=#����K#0"�,7 Q� "%)(D268:C@(b-A!b-A=#=#�)� -�C@(b%)(:-A%<-A=#=:�A-/�.24!#�?%4%��i(:-,rJ��K:�,�,!-/=#=#���AC� 3-/%)�o* "!k%�(#�i0" 1%��,�@-A%)8#���H2�� �x-/� �4%�(#�i=G�)��KG01�,7��A�B*&�,%)�P�)7> "!# 1!#�gQ�(# 3C (9=:-/%�%)�,��!:2�-A�)�%)(#�R�,u#CY�,=#%) "��!:2^h�-A!:*$Q�(:-A%<%)(#�R%)�,��7 > �,uGC��,=#%� 1�?! ��7>�o-/!:2^h/ "!b-gC���!#!G�AC�%) "��!# 326%BC���!\%)�Pu&%Pc4ef!%)(#�'!#�,u\%+C (:-A=#%)�P�)h:e ���,r\ 1�,Q %)(#�'7>�o-/!# "!#�b�/��> �,uGC��,=#%� 1��! �& 1!h�?�,!#�,�.-/0ohd-/!j* %)(G�,!n*& 32)C�8j2)2 1%@2�-A=#=#0" ;C,-AK# 10" 1%�Fb%)�9%)(#�DC��?!#!#�ACY%) 1�?!# ;2�%�=:-A�@-?*& 1�?7nc

Page 112: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ���� �

� � � �� � � � � � � � � � � � � � � � � ��� ��� �

� ��� ��� � �

� ��� � 0�=F*"! � .10324* �

e�!h%�(#�'=#�)�,r\ 1�?8:2�C@(:-/=#%��,�)h# "%�Q�-?2iC��?!:C�0"8:*&�A*k%�(:-/%g%)(G�,�)�' ;2�-9C��?!:C��,=#%�8:-/0l=G�)��KG01�,7 Q� "%)(%)(#�9%)�,��7 > �,uGC��,=G%) 1�?! �: 1! %)(#� C���!G!#�AC�%� 1��!G ;26%'=:-A�@-?*& 1�?7�� �? 1rJ�,! -q*#-/%.-L2��,%'��! Q�(# 3C ( -C���!#!G�AC�%) "��!# 326%'!#�,%�QR���)S ;2'%)�.-/ 1!G�A*�h4Q�(G ;C@( =:-/%�%)�,��!:2b26(G��8#03*[=#�)�?=:�,�)0"F[K:�qC�0;-?2)2� �:�A* -�2> �)�P��8#03-/� �l�?� > �Pu#C��P=#%) "��! �:=:-/%�%)�,��!:2 $ �g�)h57>�����b���,!#�P�@-/0"01FUhl(#�AQ 2�(#��8#03*[%)(G�>C��?!:C��,=G%$�/��,u#CY�,=#%) "��!:2�K:�$��=:�,�.-/%� 1��!j-/01 � �A*> 1!h%�(#�DC���!#!G�AC�%) "��!# 326%R=:-/�.-�*& "��7 $

ef! %)(#� 26%)8j*& 1�A29�)�,r\ 1�,QR�A*[ "! ��(:-A=#%)�,�.2 E -A!:* �/h�%)(G� �x-,rJ��8#���A* -A=#=#���J-�C@( Q�-�29%)�*&�A26 "��!:-A%)�'-?2 �,uGC��,=G%) 1�?!:2<%)(#� 26�H=j-/%)%��,�)!j2 Q�(# 3C ( *& ;*9!#��% > �:% �&-'=#�)�Pmf2�=t�oC� �:�o* � Z � W@c v (G ;2�)8#0"� 32 8j268:-A0101F C@(#�J2��,! K\F %)(#�q�,u\=t�P�) 17 �,!&%����D��! %)(#�qK:-�2� ;2k�A�D-/! "!:26=:�AC�%� 1�?! �/� %)(#�%)�@-A 1!# "!#�926�P%)h#����=G�) 1�?�iS\!#�AQ�01�o*&���H�?!L(#�AQ "%�Q�-?2����,!#�P�@-/%��A* c

�#�?�<�,uG-/7>=#0"�Uh�%�(#��=:-A%)%)�P�)! � E � m � E � Q�-?2<*&�A2� 1�?!:-/%��A*b-�2<-A!b�,uGC��,=#%� 1��!' "!b%)(#�R%)�@-A 1!# "!#�26�,%g8:26�o* K\F � 8#7>�P01(:-A�)%g-/!j* � C���01�,0"0;-A!:* f �����)(yMRhlK:�AC,-A8:26�b "%g*& ;*h!#��% C���!&���?�)7 %)�9%)(#�� Z � W ������� Q�(# 3C ( Q�-�298:26�A* %�� ���P!#�,�@-A%)�n%�(#�L%��@-/ "!# 1!G� 26�,%Pc ef! � -/�.C (G7h-/! f ����� �yMRhf -/!j-/01�?��8#�o2s�A�YM �<!#��0" ;2�( rJ�,�)K:29%)(:-A% QR�,�)�q!#��%h7h-A=#=:-AK#01�n%�� %)(#� C��?�)�)�oC�%k=j-�26%�m %��,!:2�������)7 K&F>%�(#�D-/=#=G01 ;CP-/%) "��!h�/�B%)(G� > �+* �#�)8#0"�HQ��P�)�D-/0326� *&�A26 "��!:-A%)�A*>�,uGC��,=G%) 1�?!:2�c

�g�/QR�,rJ�,��h:26 1798#03-/%) "��!:2� "! ��(:-A=#%)�P� �>26 "��!:-A010"�A*L-k=G�)��KG01�,7 1!L%�(#�$ 3*&�,!\%) �dC,-/%� 1�?!L�/��,u#CY�,=#%) "��!:2g 1! %)(#� C���!G!#�AC�%� 1��!G ;26%DC��?!&%��,u\% �'26(G��8#03*[=:-/%�%)�,��!:2HK:�h*&�A2� 1��!j-/%)�o*[-?2 �,uGC��,=#m

���

Page 113: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ? ������������� � � ������������� � � � � � ��� � ����������� � ���5�1� � � � ����� �

%) 1�?!:2bQ� 1%)( �)�A2�=:�AC�%9%)� - ��8#01� a U � ^ WYX � � ];U:WnW54 _ W � V WYX&]�W � h����9Q� 1%)( �)�A2�=:�AC�%9%)� %)(#�> �)8G01� � f 7s-/=#=# "!#�&M `Ja ]xZ ` ����� � W `�� XtW�� � � ];U:W'X:W@] � � � � $ �i�bK:��%�(h%6F\=:�A2 �A�<=j-/%)%��,�)!j2�C���8#!\%-�2 > �,u#CY�,=#%) "��!:2 �'h#K\Fq26��7 �b*&� �j!# 1%� 1��!�h -A!:*L �N26�?h Q�(# 3C (q��!#�92�(#��8#03*LK:�9C���!:2� ;*&�P�)�A*h%)(#�7>�J2�%�268G 1%@-AK#01�D*&� �:!# 1%� 1�?! "!q-kC��?!#!#�ACY%) 1�?!# ;2�%�=:-A�@-?*& 1�?7 $

ef!'%)(G ;2lC@(:-/=#%��,�5e:-�*#*\�)�A2�2 %�(# ;2 32)268G� K\F �:�.26%B*& ;2�C�8:2�26 1!G��Q�(:-/%5 ;2�V;X&]xZ\V1]fV �/W ��� 7>�A-A!&%:K\F%)(#�'%)�P�)7 > �,uGC��,=#%� 1�?! �'h\-/!j* %)(G�,!q*&�,�) "r& "!#�9- ������7h-/0I*&� �:!G 1%) "��!h�/�T%)(#�'%)�P�)7nc5e �Pu#-A7> 1!#�(#�AQ %�(# ;2g*&� �:!G 1%) "��!hCP-/!LK:�'7h-A=#=:�A*>%)�b%)(G�$CY��!#!#�oC�%) "��!# 326%�=:-A�@-�*\ 1��7 c

�gK\r& "��8:2�01FUhJ%�(#�'C��?�)�)�oC�%R*&�A26 "��!:-A%) "��!h�/�5=:-A%)%��,�)!:2�-?2 > ���,��8#03-/� �y�?� > �,u#CY�,=#%) "��! �J 32 CY�) 1%�m ;C,-A0 %)� -/!\Fh2�%)8:*&F %)(:-A%i 32�-/%)%��,7>=#%� 1!#�D%)�9�A26%.-/K#0" ;2�( %�(#�'�,u\ ;26%��,!:C��+�/�T-k*&8j-/0l�)�?8#%)�D 1!q-C���!#!G�AC�%) "��!# 326%H!G�,%�Q�����S c �g!#�9C,-A![!#�?%'�,u&=:�ACY%'268:CPC��A2)2g 1! *&�,%��AC�%� 1!#�h2��,=:-A�@-/%��9C�018j26%)�P�@2�/�B�)�,�?8#0;-A�@2������,uGC��,=#%� 1�?!:2 "! %�(#�'(# ;*G*&�,!h8#!# "%�26=j-�C��Uh&���?�i�Pu#-A7>=#01�gh� �B%)(#�+=:-/%�%)�,��!:2i-A�)�0;-/K:�,0"01�A*9���g���)�?8#=:�A*L-?C,C��?�@*& "!#�b%)� -/!q�,�)����!#�,�?8:2gC��) "%)�,�� 1��!Ic

v (G�'268:2�=# ;CY 1��!h%�(:-/%R�)�,�?8#0;-A�@2�-/!j*s�Pu#C��P=#%) "��!:2<7h-,Fb(:-,rJ�HK:�,�,! 1!:-?*&r& 326�A*\01Fb0;-AK:�,010"�A* 1!L=j-�26%DC��?!#!#�ACY%) 1�?!# ;2�%i���A26�o-/�@C@(L 32i 17 =t�?�)%.-/!\%O���?�'-/!#�?%)(#�P� ���A-�2���!lcDe �� 1%g ;2�����8#!:*L%�(:-/%C���!:CY018:2� 1��!j2 ���)��7 26 1798#03-/%) "��!:2�2�8:C (s-�2 ��8#010" 1!:-A�) ;-D-/!:* ��(:-A%)�,� � 2 f �������yMN26%�8:*&Fq-/���H8#!#m����8#!:*\�A* K:�AC,-A8:26�9-A!n 1!:CY���)���AC�%��?=t�P�@-/%� 1�?!:-/0" � -A%) 1�?!L�A���Pu#C��P=#%) "��!:2�QN-�2i8:2��A*�h:%)(#�P!L%)(G ;2Q���8G0;* CP-/010g 1!\%)� *&�?8#K#%>%�(#�L�?!#01F�26 1�?!# �tC,-/!\% f 1!:*\ 1�)�oC�%�M'�,r\ ;*\�,!:C��>%�(:-/%s- *&8:-A0H�)�?8#%)��,u& 326%.2 "!:26 3*&�n- C��?!#!#�AC�%� 1�?!# ;2�%k!#�P%6QR����S �n%)(G� ��8#0"01 1!j-/�) 3-[-A!:* ��(:-A%)�,� f �������yM *&��8GK#01�*& ;2�26�\C� 3-/%) "��!q�)�A2�8#01%.2�c

� ������� �H� H� + *�� + �� � +-.

e �:�.26%hCY��!:2� ;*&�,� Q�(:-/%h ;29 1!&���?�)7h-A0101F 7>�A-/!\%bK\F %)(G�n%)�,��7 > �,uGC��,=#%� 1��! �'h�K\F Q�-,F �A�9-*& ;C�%� 1�?!:-/��F$*\� �:!# "%) 1�?!b-A!:*$�,uG-/7>=#0"�A2�cIe %�(#�,!$=G�)��=:� 26�+-O������7h-/0G*&� �:!G 1%) "��!D�/�d�,uGC��,=#%� 1��!j2%)(:-A%��)�,rJ�A-A0;2<%)(j-/%��,uGC��,=#%� 1�?!:-/0: 1%��,7h2<798:26%�K:�'*&� �j!#�A*>Q� 1%�(>�)�A2�=:�AC�%�%��h] � � 7h-A=#=# "!#�J2 �-k*&�o26 1���A* f >EC��?�)�)�oC�% �EM<7h-A=#=# 1!G�b-/!j*L-/! -�C�%�8:-/0 f > ��8#01� �EM<7h-A=#=# "!#�#c

ef%5 ;2 %�(#�,!bCY��!:2� ;*&�,���A* (G�/Q %)�g7h-/=D%)(# 32l*&� �:!# "%) "��!$ "!&%��i%�(#�RC���!G!#�AC�%� 1��!G ;26%5=:-A�@-�*\ 1��7 cv (#�k7s- �����'*\ ��sC�8#01%�Fq 1! *&�? 1!#�q%)(# 32 0" 1�A2H "! *&�,%)�P�)7> "!# 1!#�9Q�(:-A% > ��8#01� � 7h-/=G=# 1!#� ;2H 17>m=#01�,7 �,!&%��A*>K&F -hC��?!#!#�ACY%) 1�?!# ;2�%H!#�,%�QR���)Sdc g�,!#�,�.-/010"FUh "% 32H!#��%'=:�J2�26 1KG01�9%)�n2�8:C,C� "!:C�%�01F*&�A2)CY�) 1K:�H%�(#�'7h-/=G=# 1!#�9-b!#�,%�QR���)S9(:-?2O "7>=#01�P7k�,!\%)�P*b 1!h%)�,��7h2<�/�R-926 "7>=#0"�i��8#01�Jc

� !#�,Q *&� �j!# 1%� 1��! �A�D�,u#CY�,=#%) "��!:2b ;2b=#����=:�J2��A*����?�>%)(G� C���!#!G�AC�%) "��!# 326% C���!\%)�Pu&%�h� 1!

Page 114: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � ��� � �"!������ � � ���

Q�(# ;C@(>%)(G� 7s-/=#=# "!#�$ "7>=#0"�,7k�P!&%��,*$K\F>%)(G�H!#�,%�Q��?�)Sh-A%g-$�� "rJ�,!>%) "7>�D] ;2�C��?!:26 3*&�,���A*>%)�Kt��%�(#� � Z � W b`�_J_ V;X���Q� 1%�($�)�o26=:�AC�%<%��HQ�(# 3C (D�,u#CY�,=#%) "��!:2B-/�)�N*&� �:!G�A* c v (G ;2 ���?�)798#0;-A%) 1�?!7>�A-/!j2�%)(:-A%H�,uGC��,=#%� 1��!j2�-/�)� *&� �:!G�A* %��>K:�$%)(G�b26�P%i�A��=:-/%�%)�,��!:2i%�(:-/%+-/���b!#��%+C������)�ACY%)01F(:-/!:*\01�A*'K&F'%)(G��!#�,%�QR���)SD-A%�-H26=:�ACY �:�A*H%� 17>�g]\*&8#�� 1!#�H%��@-A 1!# "!#��hA�� "rJ�,!b2���7>�RC��?�)�)�oC�%)!#�o2)2C��) "%)�,�� 1��!Ic

�g01%)(G��8#�?(n%)(# 32 *\� �:!# "%) 1�?!n(# 1!G���A2i�?! 2���7>� -�*&7 1%)%��A*&0"Fh-/��K# 1%��@-/��FnC��� 1%��,�) 3-/hdei-A�)��8G�%)(:-A%�268jC ( - � � X ` V a *\� �:!# "%) 1�?!k�A�5�,uGC��,=#%� 1��!j2T 32<%)(#�g��!#0"Fb�)�A-?26�?!:-/K#0"�'*&� �j!# 1%� 1��! -,r?-/ 10"m-/K#0"� Q� "%)(# "!q-bC���!#!G�AC�%) "��!# 326%����.-/7>�,QR����S c

v (G� "7>=#0" ;C,-A%) 1�?!:24�A�<%�(# ;2R*&� �:!# "%) "��!q-/���H%)(#�P!L*\ ;2)CY8:2)2��A*�hy���?010"�/QR�A*kK\F>-$���,=#0" ;C,-A%) 1�?!�/�R%)(#���8G0101 "!:-/�� ;-9-/!:* ��(j-/%)�P� f ����� �yM+2�%)8:*&Fq 1!nQ�(# 3C (q 1%H 32i=#�.-�C�%� ;C,-A0101Fs-/=#=#0" 1�A*dc'e�%+ ;2����8#!:* %)(:-A%$%)(G� ��8#0"01 "!:-/�� ;->-A!:* ��(:-A%)�,� f ����� �JM'!#�,%�Q��?�)S *&�J�A2'!#��%D�)�,0" ;-AK#01Fq01�A-A�)! %)(#��)8#0"�A24*\�A26 "��!:-A%)�A*$K\F' 1%@2B*&�,rJ�,0"��=:�,�@2 �J*& � �P�)�,!\%526�,%.24�/�d�,uGC��,=G%) 1�?!:2l�)��8G%) 1!G�,01FD-/�� ;2��g*&8#�) "!#�%)�@-A 1!# "!#��h#Q�(G ;C@(h268#�?���A2�%@2i%�(:-/%g*\ ��d�,�)�P!&%���8#01�A2�-A�)�'01�o-/�)!G�A*>��!q*& ��d�,���,!\%�%)�) 3-/032�c

v (G ;2 �j!:*& 1!G�L=#���A26�,!\%@2D-LC��?!&8G!:*&�)8G7�� E��%�(#�>�,uGC��,=#%� 1�?!:2H ;*&�,!\%) �:�A*LK\F ��8#010" 1!:-A�) 3--/!:*���(:-/%��,� f �������yMT-/�)�g!#�?%�-H�)�A-A01 1%�F' 1!b%�(#�, "�4!#�P%6QR����S�h�(G�/Q %)(#�P!9*&�J�A2<��!#�g�,u\=#0;-A 1!D%)(#�*&��8#KG01�+*& ;2�26�\C� 3-/%) "��!:2<%�(:-/%RQ��,��������8#!:*bK:�,%�Q��,�P!b%)(#�, "� f -H=#�� 1�?�) M5���,��8#03-/�R-/!j* �,uGC��,=G%) 1�?!=:-/%�%)�,��!:2OQ�(G�,!h%)(#�'!#�,%�QR���)S Q�-�2�0"�A26 "��!#�o* $&R-A�) 1�?8:2l�,u&=G0;-/!j-/%) "��!:25-/����C��?!:26 3*&�,���A* c � (\F&=:�?%)(#�A2� ;2 �'K:-?26�A*'��!b%)(G��268G=#=:�J26 "%) "��!b�/�

%)(#�� 1!jC������)�AC�%d0;-AKt�P0101 "!#���/�G�,uGC��,=#%� 1�?!:2��g ;2 %�(:-/%5%)(#�����A268#0"%@2 QR�,�)��*\8#��%)�+-/!$�Pu&=:�,�� 17>�,!\%@-A0-/�)%� �x-?C�%,c � �)�P=#01 3C,-/%� 1��! �/�B%)(#�'01�o26 1�?!# 1!G�926%)8j*&Fq268#=#=:�?�)%@2�%)(G ;2�(\F&=:��%�(#�A2� ;2�c

� 26 1!G�b%)(#�'*\F&!:-A7> ;Cg*&� �j!# 1%� 1��! �/�B�,u#CY�,=#%) "��!:2^h&%�(#�H 1!\%)�P�)!:-A0l26%��)8:CY%)8#���H�/� ��8#010" 1!:-A�) 3--/!:* ��(j-/%)�P� � 2 f �������yMh!#�P%6QR����S ;2>�,uG-/7 1!#�A* %)��26�,� �D%)(G�[=:-A%)%��,�)!:2hQ�(# ;C@( K:�AC,-A7>��,u#CY�,=#%) "��!:2b*\8#�) "!#�n01�A-A�)!# "!#� -/�)�q2��,�����,�J-A%)�A* ������7 %�(#�h�)�,�?8#0;-A�k=:-A%)%��,�)!:2b 1! %�(#� �:!j-/0���)� -/!# � -/%� 1�?![�A��%)(G�k(# 3*#*&�,!n8G!# 1%'2�=:-�CY�Jc v (# ;2i7 �,%)(#�\*\��01�?��FUh5eg-/����8#�Uhl�? 1rJ�A2i%�(#�9Kt�o26%C (:-A!:C�� 26�>�x-/�H�A�!�:!:*& "!#�h-h*&8:-A0<�)�?8#%)�b "!n-/!\FL!G�,8#�@-A0<!#�,%�QR���)Sdc �i�?!#�$ 32O����8#!j* c v (G ;2 ;2H*&�o26=# "%)�b%)(G�$�x-�C�%H%�(:-/%D*&�?8#K#0"�9*& ;2�26�\C� 3-/%) "��!:2'-A�)� *&�,7>�?!:26%��@-/%��A*�hd-o��%��,�H01�o26 1�?!# 1!G��h �?!%)(#�D2)-A7>�' 1!:*\ 1r\ ;*&8:-A0 !#�P%6QR����S>%)(:-A%iQN-�2 ��8:26%� "!&rJ�o26%) "�J-A%)�A* c v (G�A26�DC��?!&%��@-�*\ ;C�%����)F��:!:*&m 1!#� 2HC,-/0"04 "!&%��h*&�?8#K#%'%)(#�D 1!&���P�)�,!\%) 3-/0501 1!GS K:�,%�QR�,�,!n*\��8#K#0"�9*& ;2�26�\C� 3-/%� 1��!j2H-/!:*n 1!\%)�P�)!:-A07>�\*&8#03-/�) "%�FJc

v (G���)�A2�8#01%.242�8#���?�A26%�%)(j-/%<!#�P%6QR����S#2l7h-,FH!#�?%<01�A-A�)!b%�(#���,u\=:�AC�%��A*$-i=G�) 1�?�) \�)8#0"�A2%h?-/!j*

Page 115: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ������������� � � ������������� � � � � � ��� � ����������� � ���5�1� � � � ����� �

(#�,!:C��+%)(:-A%i%�(#�'�,u&=:�ACY%)�A*k�Pu#C��P=#%) "��!:2�*&�b!G��%+-/�) 326�Jc v (G� �Pu&%��,!:26 "��!h�/�T%)(#�A2��'�)�A2�8#01%.2�%)�0;-/�����,�l!G�,%�Q�����S#2�� -/!j* 8#0"%) 17s-/%)�P01F�%)�g(\8#7h-/! C����?!# 1%� 1��! �+ ;25-�*#*\�)�A2�26�A*H 1!D%)(#�R*& 32)C�8j2)26 "��!�/�B%)(#�DC��?!:C�018j*& 1!#�9C@(:-A=#%)�,�Pc

� ��� � � 0 >, 8 �K0��-=F, ���������� � ��� ���

�i!G�k�A�g%)(#�>7 �J26%+ 17>=:����%@-A!&%' ;2�268#�o2 %)�qK:�h-�*#*\�)�A2�26�A*�h5 1! %)(#�s26%)8j*&F[�A���,uGC��,=G%) 1�?!:2H 1!���,!#�P�@-/0Xhl-/!j* "! *&�,%)�P�)7> "!# 1!#�b%�(#�b�,u\ ;2�%)�,!:CY�$�/�O->*&8:-A0��)��8G%)�b 1! =:-A�)%) 3C�8#03-/�)hd ;2i%�(:-/%'�/�C�0;-A�) ��F\ 1!G�>Q�(:-/%' 32 7 �A-/!\%iK\Fn%)(G�b%)�,��7 > �,uGC��,=#%� 1�?! �1c v (#�,���k 32H-/! "!&%�8# 1%� 1rJ�'!#�?%) 1�?! �/�Q�(:-/%9C��?!:26%� 1%�8#%)�A2b-A! �,u#CY�,=#%) "��!�h5=:�,�)(:-A=:29-�*&��J8:-A%)�,0"F 2�8#7>7>�A*L8G= K\F %)(#�k���?010"�/Q� "!#�*& ;C�%� 1�?!:-/��Fh*&� �:!G 1%) "��!�

�<u#C��P=#%) "��! f ! M@c v (#�9-?C�%H�/�N�,uGC��,=#%� 1!#�9���H�Pu#C�0"8:*& "!#� ������7 -k!&8G7kK:�,�+*&�A2�m 1�?!:-/%��A*�h �?�i���)�?7->*&�o2)C��� 1=#%� 1��!��4c<c5cb];U ` ] � UGV a U V ^ � � b` � � W � �'W � W��hV;X� _J_ � ^ V1]fV �JXh] � ` � Z � WRht=G�)��=:� 26 1%� 1�?!�h 2�%@-A%)�,7>�P!&%R���+-/010"�,�J-A%) "��!lc���� W��j]fZ � �� V a ]xV �JX `��� f �i!#!j-/!:*#-A01�Uh ��� � ?yMJh =lc �)( ��� 1%@-A01 3C,2�-�*#*&�o*��fc

v (j-/%g ;2%h:�,uGC��,=#%� 1�?!:2�C,-A!n-A=#=:-/���,!\%)01F Kt� *&� �:!G�A* Q� "%)(h�)�A2�=:�AC�%g%)� - � Z � W@c � !&���?�)%�8#m!:-/%��,01F9%)(#�'!#�?%) "��!h�/�R- > �)8#0"� �& 32 =#(G 101� 26�?=#(# ;CP-/010"F>-A!:* =G�@-�CY%) ;CP-/010"Fb=#�)�?K#01�P7h-/%� ;C f ��(#�?7>m26S\FUh������)? � �J7 1%)(D�,%R-/0xc'h������ �yMJh#2��$ 1!9%)(G ;2�26�ACY%) 1�?!>elQ� 10"0# 1!G 1%) 3-/0"01F'7h-/SJ��%�(#�+26 17 =#01 E��F& E!#�-�2)2�8#7>=#%� 1�?!>%)(:-A%H-$��8#01�+ ;2�-b=:-A�@26 "7>��!G 1��8j2�*&�A2�C��) "=#%) "��!>�A��- b`�_J_ V;X � 2�=:�AC� �j�A*>�/rJ�P��-=:-/��%) ;CY8#0;-A�g*&��7h-A 1!lc

v �>7h-ASJ�H%)(G�b*& 32)C�8:2�26 "��!n7>�?�)�DC���!jC��)�,%��Uh# 1%gQ� 10"0lK:�bK:-�2��A* �?! - �x-/7> "01 3-/��CY����!G 1%) "rJ�%@-�2�Sh%)(:-A%H(:-�2gKt�P�,!n*& 32)C�8j2)26�o*n-/%g01�,!#�?%)(q 1!L%�(# ;2�%)(G�A26 32���%�(#�$�?�,!#�,�.-/%) "��!n�A��=:-�2�%H%)�P!:26������)7s2 �/� �<!#�?01 326( rJ�,�)Kj2�c � � 26% �<!#��0" ;2�( 2�=:�A-/SJ�,�.2$C,-A! =t�P�6������7 %)(G ;2 %.-�2�S Q� 1%�( �A-�2��Uh7h-/=#=G 1!#�?h ���?���,uG-/7>=#0"�Uh � � 8 �h%)� � � 8 ���F;�h � 8 ��� 6L%)� � 8 ��� 6 �F;�h/KG8#%g-/0326� � � ���b%)� � 919��<c�H2iQ��P010oh:7>� 26%"�<!#�?01 ;2�( 26=:�A-ASJ�,�@2HQ� 10"047s-/SJ�b2� 17> "0;-A�gC�0;-?2)26 �dC,-A%) 1�?!:2i�A��rJ�,��K:2H-�2 > �)�,�?8#m0;-/�.2 �#�?� > �,u#CY�,=#%) "��!:2 ��� � � 8 � 32O���,��8#03-/��h#K#8#%g%)(#� f �?�)%�(#���?�@-/=G(# ;C,-A010"FL-A!:* =G(#��!#�?01�?�� ;CP-/010"F26 17 10;-A��M � � ���k 32��)�,� -/�.*&�A*h-/!q�,u#CY�,=#%) "��!lc �g!LQ�(:-A%�K:-�2� ;2� ;2�%)(G ;2�C�03-�2)2� �dCP-/%) "��!h7h-?*&� $

v (G�k7h-A=#=# "!#�>�/� � X � � X rJ�,��K:2i%��L%)(G�, 1�H=j-�26%D%)�,!j26�9C,-A![K:�hC��?7>=#0"�,%)�,0"F>*\�A2)C��� 1K:�A*K&Fq->2��,%H�/� f rJ�,�)K�h#=j-�26%�m %��,!:2���Mg=:-/ "�@2H2�8:C ( -�2 f ��� ��� � h ��� � � � �F;<M@c v (# ;2g7h-/=#=G 1!#�9Q� 10"0Kt�DC,-A010"�A*k%)(G� � � � � W a ] � `�_J_ V;X��Ch:-A!:* 32�*& ;2�=#0;-,FJ�A*k "! �4 1�?8#�)� (\c��?c

Page 116: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � � � ����� ������!�� � � � ������������ � � � � �

needle

think

perambulate

envision

hang

take

hanged

envisioned

perambulated

needled

... ...

bluff bluffed

took

thought

verb past tense

�4 "��8#���=(&c���� v (#� > �������)�AC�% � -/=#=G 1!#� �#�/� �<!#�?01 ;2�(hrJ�,�)K:2�%��k%�(#�, "��=:-?26%g%)�,!:2��H�����)7s2�c

�+2k ;2bQ��,0"0iS\!#�AQ�!�hg- C��P�)%@-A 1! ���,��8#03-/�� 1%�F C,-A! Kt�L���?8#!:* 1! %)(# 32k7h-/=G=# 1!#���n7>�J2�%�T!G��01 326(h=:-?26%g%)�,!:2��A2 f C,-&c ��� B����#�.-/!:C� 32 � � 8 C��,�@-+h ����� �JMgC,-A! K:�H������7>�A*kK\F -/=#=#0"F& "!#�%)(#�H����0"01�AQ� 1!G�b�)8#0"� � �

� 8G01� f rJ�,�)K M�� C��?!:C,-A%)�,!:-A%)� f 26%��,7 f rJ�P�)K MJhF>E* �EM

v (j-/%g ;2%h#K\F -�*#*& "!#�9%)(#�D268 �>u > * �#%)�b%�(#�'rJ�,�)Kq2�%)�,7 �@c�g���)7s-/010"FUh,=:�,��=G01��Q��?8#0;*b*\�A2)C��� 1K:�� 1%��,7h2 %�(:-/%R-/���gC������)�ACY%)01F'(:-A!:*&0"�A*$K&F 268:C@(9-H�)8#0"�

-�2 � W �JZ �E`�� hJQ�(# 10"��%)(#�����,7h-/ "!# 1!G�irJ�,��K:2<-A�)�+C�0;-?2)26�o*k-?2 W 4 a W _ ]xV �JX ^ c v (G ;2< ;2<%)(G�� 1!\%)8# "%) 1rJ�C�0;-?2)26 �dC,-A%) 1�?!h%)(:-A%He<Q� 10"0l!#�AQ %��)F>%�� ���?�)7h-A01 � �Jc

� �qC,-/!�*&�A2�C��) "Kt� %)(#�q7h-/=#=G 1!#�q�/�'rJ�,��K:2$%)� %)(G�, 1��> rJ�,��K �+* �4 "7h-/�?�A2 "! - 26 "7> 103-/��x-�26(G 1��! %)� %)(#�����?�)�)�oC�% � -A=#=# "!#� ��%)(j-/%9 ;2%h�K\F 01 326%) "!#�n%)(G� f rJ�,�)K�h � 8#01� f rJ�,��K M)M+=:-/ "�@2%)(:-A%�-A�) 326�gQ�(#�,!9%)(#�+-/K:�ArJ�i��8#01�g ;2�-A=#=#01 "�A*$%)� -/0"0��<!#��0" ;26(9rJ�,��K:2 f 26�P� �4 1�?8#�)��(&c �yM@c v (G ;27h-/=#=G 1!#�DQ� 1010lK:�'%)�P�)7>�A*b%)(G� � Z � W � `�_J_ V;X���c

�+24 ;2�C�0"�A-/�4������7 �4 1�?8#�)� (\c �/hJ%�(#� � 8#0"� � -/=#=# "!#�H�A��%)�,!9�� "rJ�A24%)(G�g2)-/7 ���)�A2�8#01%�-?2<%)(#������)���AC�% � -/=G=# 1!#�?hlK#8#%'�\C,C,-?26 1�?!:-/0"01F *&�J�o2 !G��%,c �[� C,-A! *&� �:!#�b%)(G�J26�9rJ�,��K:2H%)(:-A%$-A�)�7h-/=#=:�A*h ;*&�P!&%� ;C,-A0101F K&Fh%)(G� � 8#0"�b-A!:* ���?�)���AC�%H7h-A=#=# "!#�J2�%)�hK:� � W �JZ �E`�� Q� 1%�(n�)�A2�=:�AC�%%)�b%)(G�J26�D%�Q��b7h-A=#=# 1!G�J2%h:-A!:*>%)(#�'���A26%��A��%)(#�'rJ�,��K:2�%)�bK:�D�,u#CY�,=#%) "��!:2Yc

�g��h#7>�����i������7h-/0"01FUh� W �JZ �E`��.^��� � 4�� � � b` V;X�� � Z � W f 4:M�� � � ��� W a ] f 4:M �

-/!:*

� ����� ���������������� �6.����� ��� ! �� � ���������� �!� #" ( .$� ��%'&�� (�)'*"+�+�&������%-,/.0��12�3����� �%-&�"+%-& 12(�& & %-���546647�8� 9�:)-%-� . 9;�<�=������ �!)��<()-=%-&�& )-%-���+� )/.>,/��� =12��,�.)-%?1��:�<#" )*�:�@�:)-)-��,����<.�>�:A50B" -C%-&D�FE$7#"�93"+�+

.0��C"G%'���=���/�<����0"+%-��=�:A3� � %����(8H 3%-�I��� 95J9K�KJ9L�4

Page 117: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� E ������������� � ������������� � � � � ��� � � ����������� � ���5���� � ���������

needle

think

perambulate

envision

hang

take

hanged

envisioned

perambulated

needled

... ...

bluff bluffed

taked

thinked

verb rule(verb)

�4 1�?8#�)� (\c � � v (#� > � 8#0"� � -A=#=# 1!G� �k�A� �<!#�?01 326( rJ�,�)Kj2%hn-?2 26=:�AC� �:�A* K\F %�(#���)8#0"�a �JX a@` ]6W X ` ]6W�� ^ ]6W � �AW ��������� ��� � �

� 4 a W _ ]fV �JX ^ �� � 4�� � � b` V;X � � Z � W f 4tM��� � � � � W a ] f 4tM �Q�(#�,�)� � � b` V;X+h& 1!h%�(# ;2�C,-?26�Uh# 32�%)(#�D2��,%��/�R-A010 �<!#�?01 ;2�(hrJ�,�)K:2Yc

v (G ;2H2� 17>=#0"�H�����)798#03-/%) "��! *&�,7>�?!:26%��@-/%��A2�%)(:-A%)h %��L*\� �:!#�D�,u#CY�,=#%) "��!:2g-/!j* ���,��8#03-/�.2%h 1%� ;2�!#�AC��A2�2)-A�)F9%)�b8:2��b] � �i7h-/=#=G 1!#� 2��<-bCY���)���AC�%�7h-A=#=# 1!G�b-/!j*>-$�)8#0"�i7s-/=#=# "!#�#c ����%)�,!Q�(#�,! �)�A2��A-/�.C (#�P�@2'26=:�A-AS[�A���,uGC��,=#%� 1�?!:2 f -�2H "![%�(#�>CP-�26� �/� �<!#�?01 326( =:-?26%D%)�,!:2��A2 MJhl%)(#�C������)�AC�%R7h-/=G=# 1!#�b 32�01����%R 17>=G01 ;CY 1%,c

� ��� ��� � � � � + * � ��� + �

v (#�H*\� �:!# "%) 1�?!>�/�5�Pu#C��P=#%) "��!:24�? 1rJ�,! -/K:�ArJ�+-�2)2�8#7>�A*b%)(G�H8:26�g�/�B-D26 "7>=#01����8#01�g7h-A=#=# 1!G�%)(:-A%4QN-�248#!G ������7��/rJ�P�l%)(#�RQ�(#��0"��*&�?7h-/ "! f fc �Jc'hA-A!b ;*&�,!\%) 3C,-/0?7h-/=G=# 1!#�g-A=#=#0" 1�A*'%)�g�,rJ�,�)F�,01�,7 �,!&%5�/�5%�(#�'*&�?7h-/ "! M@c v (#�'*&� �:!# 1%� 1�?!k 32%h&(G�/QR�,rJ�,��h�!#��%�0" 17> "%)�P*$%)�D%)(# 32�26 "7>=#0"��%�F&=:��/�B�)8#0"���# 1%NC,-/!qKt�'�,u\=:-A!:*&�A*>%)�9 1!jC�018:*\�H�)8#0"�A2��/�T-/��K# 1%��@-A�)FhC��?7>=#0"�,u& "%�FJc

�#�?���,u#-A7>=#0"�UhJ%)(#�'�)8G01�H�������?�,!#�,�.-/%) "!#�9%)(#�'=:-?26%�%)�P!:26�DC��?8#0;*>K:�$�,u\=:-A!:*&�A*k���)�?7��

� 8G01� f rJ�,�)K M�� C��?!:C,-A%)�,!:-A%)� f 26%��,7 f rJ�P�)K MJhF>E* �EM

%)� �

� 8G01� f rJ�,�)K M�� E�<rJ�P�)K> "! f 26 "!#��h:2�=#�) "!#��h#�� 1!#�\M%�(#�,!���,=#03-�C�� f rJ�AQ��,0 f rJ�,��K MRh >E- � M

Page 118: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � ����������� � ���5��� ������� ����� � � � ���

�P0;26�CY��!:C,-A%)�,!j-/%)� f 26%��,7 f rJ�,�)K MJhF>E*�� M

v (G ;2H�,uG-/7>=#0"�D26(#�AQg2H%)(:-A%'%)(#�b!#�?%) "��! �/��> �)8#0"� �:8:26�A*L "!n%)(# 32i�����)798#03-/%) "��!q ;2 J8# 1%�����,!#�P�@-/0��l 1%H 32 8j26�A*n%)�q*&�A2�C��) "K:�926��7 �926=:�AC� �:�A*L7h-A=#=# 1!G��h Q�(# 3C ( CP-/! Kt�9�/�O-/��K# 1%��@-/��FC���7>=G01�,u\ 1%�F;�)c � �?�)�>8:2��k 32 7h-?*&�b�/�g%�(# ;2H�,u\=:-A!:26 "��! "![%�(#� ���?010"�/Q� "!#�n2��AC�%� 1��!�h Q�(G�,�)��,u#CY�,=#%) "��!:2R-/���b*&� �j!#�A*> 1!>%�(#�DC���!\%)�Pu&%��A�<!#�P8#�@-A0l!#�,%�Q��?�)SG2�c

� ��� ��� � � � � � 0

e�! 268#7 7h-/��FUh�%�(#�,!�hA�,uGC��,=#%� 1��!j24-A�)��*\� �:!#�A*'Q� 1%�($�)�o26=:�AC�%l%��H%�Q��g7h-/=#=G 1!#� 2��l%)(#�NC������)�ACY%7h-/=#=G 1!#�?hl-/!:* -k7h-A=#=# "!#�h26=:�ACY �:�A*LK\Fn->��8#01�Jc �<u#CY�,=#%) "��!:2+-/�)�b%�(#�J2��>*\��7h-A 1!n 1%��,7h2Q�(# ;C@(q-/�)�b7s-/=#=:�A*h*& 326=:-A�@-/%��,01FhK\Fh%)(#�'%�Q��97h-/=G=# 1!#� 2%hd-/!:*L���,��8G0;-/�.2i-A�)�D%)(#� 26�b 1%��,7h2������Q�(# 3C (h%)(G� %�QR�b7h-/=#=G 1!#� 2�-/�)�DC��?!#����8#�,!\%,c

� ��� � � � ��� � ��� ��� � ������ � ��� ���

i "rJ�,!n->�?�,!#�,�.-/0�*&� �:!# 1%� 1�?!L�/�N�,uGC��,=#%� 1��!j2%h:%)(#�b "!&%��,!&%� 1�?!L!#�AQ 32i%)�s*&� �:!#�b%�(#�,7 1! -C���!#!G�AC�%) "��!# 326% C���!\%)�,u\%)h58:26 "!#�n%)(G�L2�-/7>�9%)(G�,�����,%) 3C,-/0N26%)��8:C�%�8#�)�Jc v (# 32 =#���\C��A*&8G�)�hQ� 10"0 1!\rJ��01rJ� �:!:*\ 1!#� C���!G!#�AC�%� 1��!G ;26%gCY��!:C��P=#%@2�Q�(# 3C (h7h-A=h%)�9%)(#�'���P!#�,�@-A0<2�%)��8:C�%)8G�)�A2� 3*&�,!\%) 1m�:�A* c

� 17> "0;-/�l%��'%)(#�g%)(#�P���)�P%) ;CP-/0G26%)��8:C�%�8#�)�+*&�A2�C��) "Kt�o*b-/K:�ArJ�UhJ-$CY��!#!#�oC�%) "��!# 326%�2�F#2�%)�,7 C,-/!Kt� C��?!:C��, "rJ�A*L�/�+-?2$- 7 �AC (j-/!# 3267 �����'7h-A=#=# 1!G�s������7 *&�?7h-/ "![ "%)�,7s2i%)�h�@-A!#��� 1%)�P7h2�cv (#�b*&�?7h-/ "!h 1%)�P7h2�-A�)�$%�(#�hV;X _ Zy] _G` ]�]6W � X ^ �A�R- ���,�o*y������Q�-/�.* !#�P%6QR����S�h:-A!:*L%)(#�'�.-/!#�?� 1%)�P7h2�-/�)�'%�(#� �JZy] _ Zy] _G` ] ]�W � X ^ c

�+2$ 1! %�(#�h=#�)�,r\ 1�?8:2b*& 32)C�8:2�26 "��!�h���!#�h����y8G 1�)�o2$- > ���?�)���AC�% � -A=#=# "!#� ��-A!:* - > � 8#0"�� -/=#=# "!#� �R%)� *&� �:!G�n�,u#CY�,=#%) "��!:2 �H�,uGC��,=#%� 1��!j2k-A�)� %)(#� 26� 1%)�P7h2 �����hQ�(# 3C ( %)(#�,���n ;2h-*& ;2�C��)�,=j-/!:C�F9K:�,%�Q��,�P! %�(#�'�)�A2�8#01%.2��/�B%)(#�'%�Q��b7s-/=#=# "!#�J2Yc

ef!9%)(#�gCY��!#!#�oC�%) "��!# 326%�C��?!&%��,u\%)h�%�(#�i 3*&�,!\%) �dC,-/%� 1�?!b�/�l%�(#� �������)�ACY% � -A=#=# "!#�'=#�)�A2��,!\%@2!#�b*& �hCY8#01%�FJc v (G ;2<7h-/=G=# 1!#�D2� 17>=#0"FDC���!:2� ;2�%@2<�/�5%�(#�H-A�����,�A*926�,%��/� C������)�ACY%�*\��7h-A 1!9-/!j*

%'47�0"+�#"�9*� �<()- �!A�& (+E 12%-��+� 12��,/.)-87%-� . ����()?"�(0 1��!.C��(�)' �:A 12��� �<#12� )/. ,>�:..�%'��� �<� �� �<%-� "G��, �!%-�54�47�/&<(C1<� �=1��!& 9���/"+��,>�:%-�$%'�<�,/&�����()?"$(0D12���& %?"+�� #">�7�1 �.� %-���&#4

Page 119: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ( ����������� � �������������� � � ��� ��� � � ����������� � ���5���� � ���������

�@-/!G���9=:-/ "�@2�c �#���'�,uG-/7>=G01�Uh#%�(#�926�,%+�/�gCY���)���AC�%g7h-/=G=# 1!#� =:-/ "�@2i�����"�<!#�?01 326( rJ�,�)K:2g-/!j*%)(#�, "�H=:-?26%$%��,!:2�� ���?�)7h2Yc v F&=G ;C,-A0101Fgh - ^ Z � ^ W.] �A��%)(G�>2��,%'�/�g=:-A 1�@2H%�(:-/%DC��?!:26%� 1%)8G%)�9%)(#������)���AC�% � -A=#=# 1!G�k 32�8:26�A*h-?2O%�(#�9] ��` V;X#V;X�� ^ W@]t���?�H-9C��?!#!#�AC�%� 1�?!# ;2�%�!#�,%�QR���)Sdc

ef%l 32 %�(#��=#�)�?K#01�,7��/�:Q�(:-A%<CY��!:2�%) 1%�8#%)�o2 %�(#� � Z � W � `�_J_ V;X�� "!D-iC��?!#!#�ACY%) 1�?!# ;2�%526FG26%��,7%)(:-A%HQ� 10"04K:�b%)(G�b7h-/ "!L 1%��,7 �A�g*& 32)C�8:2�26 "��!n(#�,���Jc � �AC,-/0"0l%)(:-A%'%)(#� � 8#0"� � -A=#=# 1!G� 32H-*& ;2�%) 1!jC�%�7h-A=#=# "!#�b%)(:-A%�7h-,Fk=j-/�)%� ;-A0101F 7h-/%.C (9%)(#� ���?�)�)�oC�% � -/=#=G 1!#�Gc

v (G�n8:268:-A0'-/=G=#�)� -�C@(�hi%�(:-/%>(j-�2kK:�,�,! 8j26�A* -A017>� 26%9�,u#CY018:2� 1rJ�,0"Fn 1! C��?!#!#�AC�%� 1�?!# ;2�%�,u#CY�,=#%) "��!#m�01�o-/�)!G 1!#�b=:-A=:�,�@2�%)(:-A%HQ��P�)�'�)�,r\ 1�PQ��A*k=G�)�,r\ 1�?8:260"F> 1!h%)(G ;2�%)(#�A2� ;2 f �Jc �#c2h���8#0"01 1m!:-/�� ;- � ��(:-/%��,�)h ������� � � -A�@C@(#7h-/!�h����� � � �<03-/8#% � � C ��01�,0"0;-/!j*�h ����� � � � 8#7 �,01(:-A�)% �� C���01�,0"0;-A!:*�h���� � ( � �J�, ;*\�,!&K:�,��� � � C���01�,0"0;-A!:*�h �������yM� 32 ������%)(G� � W ^ W `��)a U:W � %��>2�=:�AC� ��F%)(#� � 8#0"� � -/=#=G 1!#�b%�(:-/%g*&�P%)�,��7> 1!#�o24%)(#� 26�,%R�/�B�,u#CY�,=#%) "��!:2Yc v (# 32�26=:�AC� �dC,-A%) 1�?!hC,-A! K:�7h-�*&�+ 17>=#0" ;C� "%)0EF$�?�i�Pu&=#0" ;C� "%)0"FJc

v F&=G ;C,-A0101Fght%�(#� � 8#0"� � -/=#=# "!#�h ;2'C@(#�J2��,! -?2H��!#�9Q�(# ;C@(n ;2HS\!#�AQ�![%��L8#!j*&�,�)0" 1�D%)(#�%)�@-A 1!# "!#� 26�,% f �Jc �#c2h# �� "%�Q�-�2g8:26�A*h%)�>�?�,!#�,�.-/%��$%)(G�$%)�.-/ "!# 1!#� 26�P%�� ��8#010" 1!:-A�) ;- � ��(j-/%)�P�)h�������yMJhy�?�< 1%5 ;2l 1!j*&8:C��A*H���)�?7�-/!b�Pu& 326%) "!#��%)�.-/ "!# 1!#� 26�,%5K&F' "!:26=:�AC�%� 1�?! f � c �#c2h/%�(#��7h-A=#=# 1!G��/� �T!G��01 326(qrJ�,�)K:2�%)�9%)(#�P 1��=:-?26%�%)�P!:26�H������7h2 � � -/�.C (#7s-/!�h ����� �yM.c

g "rJ�,! 2�8:C@( - � 8#0"� � -A=#=# "!#�n-A!:*[%)(G� �������)�AC�% � -A=#=# 1!G��h<%)(G�k���A26�A-A�@C@(#�,�' ;2'-AK#01�%)�q26=:�AC� E��FL%�(#�>2��,%H�A�g�,u#CY�,=#%) "��!q=:-/%�%)�,��!:2�c v (#�qV i_�� V a V1] `/^@^ Z i_ ]xV �JXs�A��%)(G ;2H7>�,%�(#�\* ;2k%�(:-/%>%�(#�nCY��!#!#�oC�%) "��!# 326%>!#�P%6QR����S Q� "010g01�A-A�)! %)(:-A%h26=:�AC� �:�A* � 8#01� � -/=#=G 1!#�Gc�ex� 1%*&�J�A2%hl%�(#�b�,uGC��,=#%� 1��!j2i%)(:-A%H(:-,rJ�bK:�,�,!n 3*&�,!\%) �j�A* "! -�*&r?-/!jC��kQ� "0105 1!:*\�,�A* K:�ACY��7>�D%)(#��,u#CY�,=#%) "��!:-A0 =:-A%)%��,�)!:2� 1! %)(#�D�� 1rJ�P!hC���!G!#�AC�%� 1��!G ;26%N26FG26%��,7nc

ef%l 32 %�(# ;2l 17>=G01 ;CY %d-?2)268G7>=#%) "��!'%)(j-/%�e:Q� 1010����\CY8:2 �?!$!#�AQ'cBe�%5 ;2l-+C��) "%) ;CP-/0J-?2)2�8#7>=#%� 1��!�hKt�oC,-/8:2��� �:%�(#��!G�,%�Q�����SD*&�J�A2�X ��]\01�A-A�)!b%�(#���,u\=:�AC�%��A* � 8#01� � -A=#=# 1!G��hJK#8#%5 1!:2�%)�A-?*b26�?7>�-/01%��,�)!j-/%) "rJ� f %)(:-A%b ;2$��J8:-A0101F -AK#01�h%�� f =:-A�)%) 3-/0"01F:MH 17 =#01�,79�,!J%H%�(#� ���?�)�)�oC�% � -/=#=G 1!#�\MRh%)(#�,!b%�(#�+C (#� 26�,!92��,%��/�I�,u#CY�,=#%) "��!:2l7h-,F'K:�i "!:C������)�ACY% ��] U:W � � V � � � W �&W � XtW�� � V1] U � W ^�_ W a ]] � ` b`�_J_ V;X �>] U ` ]�];U:WbX:W@] � � � � ����W ^ X ��] � W `�� X&c��i�AQR�,rJ�,�)h\(#�AQ�Q���8G0;* "%iK:�b=:�J2�26 "K#01�%)�n*\�,%)�,��7> 1!G�$Q�(# 3C ( � 8#0"� � -A=#=# 1!G�L%)(G�>!#�,%�Q��?�)S *&�J�o2$01�A-A�)!�h5 �� "!:*&�,�o*[-A01%)�P�)!:-A%) 1rJ�o2C,-/!hK:�b2�(#�AQ�!L%)�b�Pu& 326% $

Page 120: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � ����������� � ���5��� ������� ����� � � � � �

� ��� ��� � �+�<� � ����� � � " $�@�� � ��� � � ��� ���4��� � � � �<� �

�i!G� QN-,F %��>*\�,%)�,��7> 1!G�i%�(#�D26�,%g�/���Pu#C��P=#%) "��!:2� 1!n-9C��?!#!#�AC�%� 1�?!# ;2�%gC���!\%)�,u\%� ;2�%��>*\�,%)�,��m7> 1!#��%�(#� � 8#01� � -/=G=# 1!#�b%�(:-/%R ;2�01�A-A�)!#�A*9K&Fb%�(#�H!#�,%�QR���)Sdc�e �l%�(#�,�)� -/�)� -/01%��,�)!j-/%)� � 8#0"�� -/=#=# "!#�J2<%�(:-/%�%)(G��!#�,%�Q��?�)SbCP-/!b 1!j*&8:C���������7�-H%��@-/ "!# 1!G�$2��,%)h?��!#�g7k8j26%5 ;*&�,!\%) E��F'Q�(# ;C@( ;2 `Ja ]xZ ` � ��� "!:*&8:C��o*�h&%��k=#����=:�,��01Fh*&�o26 1�?!:-/%��'%)(#�D26�P%��/���,uGC��,=G%) 1�?!:2�c

� 2� 17>=G01�Uh,!#�ArJ�,0Xh�7h-A=#=# 1!G�H%@-?26S$Q� "010#K:�g*&�o2)C��� 1K:�A*$(#�,����%)�' 10"018:2�%)�.-/%)��%�(#�� 17 =t�?�)%.-/!\% ;2)2�8#�A2Yc �J�,� v -AK#01�\c��H�����g-9268#7>7s-/�)Fb�A�<%�(#�'7h-/=G=# 1!#�Gc

v -AK#01��\c�� � � 26 "7>=#01��%��@-/ "!# 1!G�'26�,%B%)(:-A%�CP-/!bK:�H*\�A2)C��� 1K:�A*$K\F'%6QR�'-/0"%)�,��!:-/%��g26�,%.2<�/�d�)8#0"�A2-/!:*h�,u#CY�,=#%) "��!:2Yc

�<-/%�%)�,��! ef!#=#8#%.2 v -/�����,%

=� ��� ��� �= � ��� � � �=�� ������� �=�� ��� �� �=�� ��� ��� �=� ��� � � �= � � ����� �=�� � � �� �

v (G�,�)�'-A�)�D-/%�0"�A-�2�%�%�Q��b�)8G01�H7h-A=#=# "!#�J2�%)(:-A%gC���8#03*>=:-/��%) ;-A010"Fk "7>=#01�P7k�Y!&%B%)(# 32�7h-/=#m=# 1!#� f ���)�?7 "!#=#8#%D=:-/%�%)�,��! %��n%@-A�)���P%b=:-/%�%)�,��! MRh<Q� "%)( �?!#�h�,u#CY�,=#%) "��! �o-�C@(lc v (#���:�.26%�)8#0"� f � �/MR ;2�2� 17>=#0"Fb%)(:-A%i%�(#�'%@-A�)���P%���8#%�=#8#%g ;2� ;*\�,!&%� ;C,-A0 %��b%)(#�H����8G�)%)(q 1!#=G8#%��#=:-A%)%��,�)!

_ �+���?�)7h2�%�(#�'�,u#CY�,=#%) "��!lc �i!q-/0"%)�,��!:-/%� 1rJ�H��8#01� f � �yM� 32�%)(:-A%i%�(#�'%@-A�)���P%i 32���y8j-/0l%)� �H �f -/!j* �?!#01FD �YMl 1!G=#8#%@2 �g-/!j* �H-A�)�g ;*&�P!&%� ;C,-A0fc �<-A%)%��,�)! _�� ;24%�(#�,!b%)(G�g26��0" 1%.-/�)FD�,uGC��,=#%� 1��!Ic

� (G ;C@(n=:-/%�%)�,��! f 2@MH2�(#��8G0;*n��!#�90;-AKt�P0�-�2H%)(G�k�,uGC��,=G%) 1�?! f 2@M�(#�,����� �H2H!#��%��A*n-/K:�ArJ�Uh%)(#� C���7 7>��!q=#�@-?C�%) 3C��b(:-�2HK:�,�,! %)� *&� �:!G�b�,u#CY�,=#%) "��!:2gQ� 1%)( �)�o26=:�AC�%'%)�h%�(#�k��8#01�b%�(:-/%Q�-�2g8:26�A*h%)� �&WYXtW �)` ]�Wi%�(#�$%��@-/ "!# 1!G�>2��,%,cge �Re�(:-?* 8:2��A* � �'%)�sC��)�A-A%)�'%)(G�$%)�.-/ "!# 1!#� 26�P%)h-/!:* 1!j26�,��%)�A* _ �k7s-/!\8:-/0"01FUh5%)(#�,! %)(# 32 =:-A%)%)�P�)! Q��?8#0;*�h<K\F %�(# ;2'=#�@-?C�%) 3C��Uh4K:�h0;-AK:�,010"�A*%)(#�D�,u#CY�,=#%) "��!lc �i!n-A!:-/0"F#2� ;2%hd%)(#�,!�ht�A��%�(#�$!G�,%�Q�����Sk�����+%)(#�D�,u& 326%��,!:C��'�/�N-9*&8:-A0<�)�?8#%)�Q���8G0;*k%��A26%�������-A!&F9�)�P=#�)�A2��,!\%@-/%� 1�?!:-/0d*& � �P�)�,!:CY�A2<Kt�P%6QR�,�,! _ �H-/!:*>%�(#�i�?%)(#�P�)h�� �)�,�?8#0;-A� �2h

Page 121: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

��� ����������� � �������������������������� ������������������������������������

=:-/%�%)�,��!:2�ce ��h\��!>%�(#�H��%�(#�,��(:-A!:*�h � �$QN-�2 8j26�A*>%)�D���,!G�,�@-A%)�H%�(# ;2�%��@-/ "!# 1!G�b26�P%)h&%�(#�H=:-A%)%��,�)! _��

Q���8G0;*bKt�+C��?!:26 3*&�,�)�o* %�(#�H-H=#�� 1�?�) :�,uGC��,=#%� 1��!���%)(#�g��8G%@C��?7>���/� -/!> "!&rJ�A2�%) "�J-/%� 1�?!b 1!\%)�'-A!�,u& 326%��,!:C����/�I-H*\8:-/0#����8#%���Q��?8#0;*'=t� 2)2� 1K#0"F$K:� y8G 1%)�N*& ��d�,���,!\%)hA�,rJ�,!$%�(#��8G��(b%)(G��%)�@-A 1!# "!#�26�,%g-A!:* %�(#� �:!:-/0l%��@-A 1!#�A*>!#�P%6QR����S>Q��?8#0;*>K:�$%�(#�D2)-/7 �Jc

� (G ;C@( *&�A26 "��!:-A%) "��! �/�9�,uGC��,=#%� 1�?! =:-A%)%)�P�)!:2h ;2k "! �x-?C�%qC������)�AC�% � eb=#�)�?=t� 26� %�(:-/%!#�, 1%�(#�,�< 32�cBe�%� 32T!G��%� "7>=:����%@-/!\%<Q�(# 3C (b��8#01�gQ�-?2 8:2��A*b%)�'���,!G�,�@-A%)�g%)(#�g%)�.-/ 1!G 1!#�D26�P%)hJ!#��� ;2 1%l "7>=:����%@-/!\% Q�(G ;C@( ��8#01�B%)(#���)�o26�A-A�@C@(#�,�l7> "��(\%t "!:*&8:CY�T������7 %�(:-/%5%)�.-/ "!# 1!#�g2��,%��A�@-A%)(#�P�)h��!#�+26(#�?8#0;*b*\� �:!#�g�,uGC��,=#%� 1��!j2��<V1];U � W ^�_ W a ]l]��$] U:W � Z � W b`�_J_ V;X��$];U ` ]4];U:W a �JX#X:W a ]fV �JXGV ^ ]

� W `�� XGV;X�� ^ �o^ ]�W V1] ^ W � �� 1!:*\8:C��A2<���)��7 %)(j-/%�%)�.-/ "!# 1!#� 26�,%�h&Q�(# 3C ( Q���8G0;*>K:�'*&�,%��AC�%@-AK#01� -/%26��7 �9V;X&]�W � W��JV ` ]�W�2�%@-A���$�A�<0"�A-/��!# 1!G�#c

v (G ;2$�����)798#03-/%) "��! 0"�A-�*G2 %�� - =#�.-�C�%� ;C,-A0�=#�)�?K#01�P7nc� g�,!#�,�.-/010"FUh< 1%9 ;2$rJ�P�)F *& ��sC�8#0"%%)�h*&�P%)�,��7> 1!#� �q-A%'-/!\Fq26%@-A���b�A��0"�A-/��!# 1!G� �hQ�(G ;C@( 7s-/=#=# "!#� ->C���!G!#�AC�%� 1��!G ;26%g!#�,%�QR���)S(:-�2H 17 =#01�,7 ��!\%)�A*dc��<u#CY�,=#%' 1!nrJ�,��Fn2� 17>=#0"�'!#�,%�Q��?�)SG2%hl 1%H 32H���,!#�P�@-/0"01Fh!#�?%$=:�J2�26 1KG01�9%)� 1!\%)�,��=#�)�,%'%�(#�>Q��P 1��(\%@2$�A�+-L!#�,%�Q��?�)S 268:C@( %)(:-A%b��!#�qC,-A! �,u\%)�.-�C�% -/! 8#!:*&�P�@26%.-/!:*G-/K#0"��)8#0"�Jc v (# ;2H=#����K#0"�,7 ;2HQ��P0101m�S\!#�AQ�! -/!:*n 1!\%)�,!j26 1rJ�P01Fh�)�A2��A-/�.C (G�A*L 1! %)(#� C��?!#!#�AC�%� 1�?!# ;2�%01 1%��,�@-A%)8#����� "% 32HS&!#�AQ�! -�2H%)(G� � Z � W>W��A] �)`Ja ]xV �JX =#����K#0"�,7 f � c �#c2h� g 10"�A2�� �g7>0" 1!�h ����� � �

� C � 10"0;-/! � �J7>�?01�,!j26S\FUh ��� ��� � v �AQR�,010 � �J(:-,r\01 "S�h �������yM.c��798#01%� 10;-,FJ�Y�i!G�,%�Q�����SL%�(:-/%D(:-�2$K:�,�,! %)�.-/ "!#�A*n��! %�(#�>*G-/%@-L "! v -/KG01� &c��Hh ���?�$�,u\m

-/7>=#0"�Uh#7h-,F>K:�9-/KG01�$%��h7h-/=q-/0"0<=:-A%)%)�P�)!:2HCY���)���AC�%�01FUh#K#8G%H!#�, "%)(#�,�g�,uG-/7> "!:-/%� 1�?! �A�R%)(#�Q��, "��(\%@2 !G�������P!#�,�@-A01 � -/%� 1��! %)�A2�%) 1!G�$Q� 10"0:�)�,rJ�A-A0:Q�(# ;C@(>�/�B%)(G�H�)8#0"�H7h-A=#=# 1!G�J2 � �H��� � �

f ���D2���7>� -/01%��,�)!j-/%) "rJ��MR 1%H0"�A-/��!#�A* V;X#V1]xV ` ����� hl%)� _G`�� ]xV ` ����� �)�A-A01 � �$%)(G�9C������)�AC�%+7h-/=#=G 1!#�Gc�i!G01F "! 26 "7>=#0"�>=:�,�@C��P=#%)����!:29*&�J�A29-/! �,uG-/7 1!:-A%) 1�?! �/�D%�(#�hQ��, "��(\%@29*&8#�) "!#� %)�@-A 1!# "!#�-/010"�AQ 8j2T%��'�A-�2� 101FDrJ�,�) E��F'%)(:-A% %�(#���,u\=:�AC�%)�o*$�)8#0"��Q�-?2 0"�A-/��!#�A* f -?2<Q�-�2�2��,�,!b 1!b%�(#� � 8#0"��/� � �b%@-�2�S�h: 1!%��(:-/=#%��,� �yM@c

�+24��!#���A�d%)(#�R7h-/ "!bC��?!&%��) 1KG8#%) "��!:24�A�d%)(# 32 %�(#�A26 32%hJel=#����=:�J2��H-A!9-/01%��,�)!j-/%) "rJ��2�%)�@-A%)�,�?F%)�+-�*#*&���A2)25%)(# 32 =#�)�?K#01�,7 c��<r& 3*&�,!:C��RC��?!:C��,��!# 1!G��Q�(# ;C@('�)8#0"� 7s-/=#=# "!#��(:-?24K:�,�,!$ "!:*&8:CY�A*-/%q-/! "!&%��,�)7 �A*& ;-A%)�q26%.-/�?�[�A�b01�o-/�)!G 1!#� C,-A! K:� �J-/%�(#�,���A* K\F 26%�8:*&F\ 1!#� %�(#� � W `�� X#V;X �� � X ` V a ^ �A�5%)(#�g!#�,%�QR���)S9*\8#�) "!#�$%��@-/ "!# 1!G�#c � �AC,-/0"0#%)(j-/%� "!>%)(G� � 8#01�g�/� � � %.-�26S,h& "%�Q�-�2����8#!:*n%)(j-/%'->2� 17>=G01�'=:�,�@C��P=#%)����!n01�o-/�)!G�A*�� � �/�R%�(#��� �>=:-A%)%)�P�)!:2 J8# 3C S\01FUh#0"�A-,r& "!#�9%)(#�

Page 122: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�������������������������� ������� ��������� � ���

=:-/%�%)�,��!�� � � m�� � � -�2<%)(G����!#0"F$ 1!jC������)�AC�%�01F'7h-A=#=:�A*$=:-/%�%)�,��! ���?�R-H26 "��!# �dC,-/!\%�=#�)�?=:���)%� 1�?!�/�G%)�@-A 1!# "!#�g%) 17 �Jc �g!:-/0"F#2� ;2 �/�G%)(G� !G�,%�Q�����S � 2 Q��, "��(\%@2dC���! �j�)7>�A*g%)(:-A%4 "%l(:-�*H01�o-/�)!G�A*H%)(#�� 8#0"�'�/� � �>-/%g%)(# 32i2�%@-A���Uh:Q�(# ;C@(h�,u\=#0;-A 1!:2�Q�(&F 1%gQ�-�2�7h-A=#=# 1!G�9-/010 � �)�,�?8#0;-A� �#=:-A%)%��,�)!:2f Q� 1%�(h�)�A2�=t�oC�%�%)�b%�(#� � 8#0"�'�/� � �yMNC��?�)�)�oC�%)0"FJc

v (j-/%b ;2^h<%)(#�>�x-?C�%$%�(:-/%9-A010�%�(#�h�)�,�?8#0;-A�$=:-A%)%��,�)!:2$QR�,�)� (:-/!:*\01�A* C��?�)�)�oC�%)0"F -/%b%)(G ;226%@-A���Uh\-A!:*k%)(G��=:-/%�%)�,��!�� � � m�� � � QN-�2<!#�?%)hJQ�-?2�-'26%��)��!G�$ 1!j*& ;C,-A%) "��!b%)(j-/%�%)(#� � 8#01���A� � �(:-�*hKt�P�,!h 17>=#0"�,79�,!J%)�A*$K\F>%�(#�'!#�,%�Q��?�)Sdc�e�!h%�(# ;2�2� 17>=#0"�HCP-�26�gh#%)(# 32�268#=#=:� 26 1%� 1�?!nC��?8#0;*Kt�DC��?! �:��7>�A*kK\Fh*& "�)�AC�%�01Fb "!:26=:�AC�%� 1!#�b%�(#�'Q��, "��(\%@2Yc

� 17> "0;-/��01FUhA��!G�'C���8G0;*b��K:2��,�)rJ�g%)(#�+01�A-A�)!# "!#�'Kt�P(:-,r& "��8#�R�/�B- !G�,%�Q�����Sb%)�.-/ 1!G�A*k��! %)(#�*#-/%.-L 1! v -AK#01� \c��?cne �+- !#�,%�QR���)S Q�-?2 ���?8#!:* %)� y8# 3C S\01Fq7h-/= -/0"0�=:-A%)%��,�)!:2DC������)�ACY%)01F�,u#CY�,=#% _ �Ch ` X �> 1%$�?8#%)=G8#%9- � ����� _ �k "!:26%��A-�* �/�g%�(#�h�,u\=t�oC�%)�A*nr?-/0"8#�>�/� � f �?�926�?7>� 1!\%)�,��7>�A*& 3-/%)�gr?-/0"8#��MRh:%)(G�,!L%�(# ;2�K:�,(:-,r& "��8#�gQ��?8#0;*hK:�9-/!L "!:*& 3C,-/%� 1��!q%)(:-A%H%)(G�$!#�,%�QR���)S(:-�*k "7>=#0"�,7k�P!J%)�A*'%)(#�g�)8#0"� � �?c v (#�H=:-A%)%��,�)! _ �iC��?8#0;*9%)(#�,!9K:�i03-/K:�,0"01�A*9-/!9�,uGC��,=#%� 1��!Ic

v (G ;2 K:�,(j-or\ 1�?8#�� ;2<=#���AC� ;2��,01FDQ�(:-/%RQ�-?2T����8G!:*k 1! 26 "7k8G0;-/%� 1�?!:2�c � ��m �/m��i���,�A*y���?�)Q�-A�@*!#�,%�Q��?�)ShQ�-?2 %��@-A 1!#�A* � �?!n%)(#�9*G-/%@-> "! v -AK#01��\c���cDef! -/0"04K#8G% �b�/�R%)(#��� ���>%)�� ;-A0;2%hd%)(#�=:-/%�%)�,��! _ �HQ�-?2O%�(#�'0;-?26%g=:-/%�%)�,��! 0"�A-/��!#�A* c

ef%'Q�-?2H%6F\=# 3C,-/0"01F>����8#!j*[%)(:-A%b-A010<=:-A%)%��,�)!:2hW�� a W _ ] _ � QR�,�)�b0"�A-/��!#�A* y8G ;C@S&0"FL-A%'%)(#�Kt�P�� 1!G!# 1!#�h�A�g%)�@-A 1!# "!#��h ���?0101�AQR�A* K\F -/! �,u\%)�,!j*&�A*n=t�P�) 1�\*nQ�(#�,��� _ �bQ�-?2 %)(G�k�?!#01Fn���,m7h-/ "!# 1!#� 1!:C��?�)���AC�%g=:-/%�%)�,��!lc��J�P� �4 1�?8#�)� &c �/hlQ�(# ;C@( =t�?�)%��@-,F#2'-h%6F\=# 3C,-/0 f -A!:* -�CY%)8:-A0 M%)�@-A 1!# "!#�L��8#!lc �i010�=:-A%)%��,�)!:2D-/���>01�A-A�)!#�o*[Q� 1%�(# 1! %)(#���:�@2�% � ���L�,=:�\C (j2$�,u#CY�,=#%i���?� _ ���

-/!#�?%)(#�,��� � �b�,=:�\C@(:2<�/�l%��@-A 1!# "!#�D-/�)�g�)� y8# "�)�A*$%��'7h-/=b%�(# ;2<=:-A%)%)�P�)! C������)�AC�%�01F f �:!# 326(# "!#�-/% � � � �,=:�\C@(:2 M.c

v (G�k0"��!#� � 01�o-/�)!G 1!#�>=G0;-/%��A-/8 � %�(:-/% C,-/! K:�>2��,�,! 1! �4 1�?8#�)� &c �>Q�-�2H����8#!j*[%)�hK:�h-C���7>7 ��!$���A-A%)8#���H�/�5%�(#�H01�o-/�)!G 1!#�D%)�) 3-/032�C��?!:*&8:C�%��A* c �J8jC (>=G0;-/%��A-/8Gu�h\ 1!>Q�(# 3C (���8:2�%���!#�=:-/%�%)�,��! f _ �/M4QN-�2R26%) "010# "!:C��?�)�)�oC�%)hJr?-/�� 1�A*b 1!b0"�,!#��%�(k���)�?7 �H%)� � ���$�,=:�\C@(:2%hJQ� "%)( - 7>�A-A!�/� ��� � �,=:�\C@(:2�c� g 1rJ�P!>%)(:-A%�%)(#�+7>�A-/! 01�A-A�)!# "!#�$%� 17>�g�ArJ�,�@-A010:Q�-?2 � � �b�,=:�\C@(:2%h#�?!#�DC,-/!26�,�D%)(:-A%i7>� 26%�%��@-/ "!# 1!G�k%� 17>�H 32i*\�,rJ��%��A*>%)�>0"�A-/��!# 1!#�9%)(G�$2� 1!#�?01�D�,u#CY�,=#%) "��!h=:-A%)%)�P�)! _ �-o��%)�P� 0"�A-/��!# 1!G�b-/0"0:�)�,�?8#0;-A��=:-A%)%)�P�)!:2 y8# 3C S\01F clef! �i=G=t�P!:*& 1u� %)(#�+ 17>=:-?C�%<�A� f *&F\!:-/7 ;C/M�,u#CY�,=#%) "��!>0"�A-/��!# 1!G�b��!L%��@-A 1!# "!#�b%) "7>�A2< ;2�*& 32)C�8j2)26�o* 1! 7>�����'*&�,%.-/ 10xc

� � & %-�� &<� �!�C"�:�2"��C��1<I .�� ��.0�:� �!� %-�����;��%-� �@,���,=��+�<(,�� �4 K�� )-#�:�<�%-��>� �!� � ��4 �J�3�:�0"8�.C�1<�H��C�:�21<�CL�(.;"�:�<�4

Page 123: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ��� ����������� � �������������������������� ������������������������������������

Epochs

Patterns

0 50 100 150 200 250 300 3500

1

2

3

4

5

�4 1�?8#�)��\c ��� v (G�k!\8#79Kt�P���/�� "!:C��?�)�)�oC�%H=:-A%)%)�P�)!:2HrJ�,�.268:2i%��@-A 1!# "!#�>%) "7>� f �,=:�\C (j2 M������D-��m �/m�� ���,�A*y���?�)QN-/�@*9!#�,%�Q��?�)S>0"�A-/��!# 1!#�b%�(#�'2� 17>=#0"�i%��@-A 1!# "!#�926�,%� "! v -AK#01��\c��?c �i�?%)�H%�(:-/%� �A�5%)(#� �'=:-/%�%)�,��!:2�-/���i0"�A-/��!#�A*b 1!b%)(G� �:�.26%�%)(G 1�@*b�/�I%)�.-/ 1!G 1!#�'%) "7>�Uh?-/!:*9%)(#�g�)�,7s-/ 1!G 1!#�� � �9�,=:�\C@(:2i-A�)�D*&�,rJ�?%)�A*>%��k0"�A-/��!# 1!#�b%�(#�'��!#�'���,7h-/ "!# 1!G�$=:-A%)%)�P�)!lc

Page 124: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�������������������������� ������� ��������� � � ���

v (G�,�)�bQR��8#03*L-/=G=t�o-/�'%)�hK:�9- �x-/ "�)0"FLCY01�A-A�H*& 3C (G��%)�?7kF 1!L%�(#�b%)�.-/ "!# 1!#� =:-/%�%)�,��!:2H-�2�,r& 3*&�,!:CY�A* K\F �4 1�?8#�)��&c � � � ^ ]#=:-/%�%)�,��!:2�-A�)�g(:-/!:*\01�A*9C������)�ACY%)01FDK&Fb%�(#�g�A-/��01Fb7h-A=#=# 1!G�01�A-A�)!#�A*HK\Fi%�(#��!#�,%�Q��?�)S,h,Q�(# 10"����!#� f �?�4%�QR�&M:=:-A%)%)�P�)!:25-/��� �Pu#C��P=#%)�A*����)��7�%)(# 32 7h-/=#=G 1!#�Gcex�B��!G�bC��?!:26 3*&�,�@2�%)(G� 7s-/=#=# "!#�9 17>=#0"�,79��!\%)�A*bK\F>%)(#�D!#�,%�Q��?�)Sh-A%i�P=t�\C@(�� � �k%��kK:�D%)(#�� 8#0"� � -/=#=# "!#��hN-/!:* %)(#�q%)�@-A 1!# "!#� 26�,%9%)� �,79Kt�\*\F %)(#�����?�)�)�oC�% � -A=#=# "!#��h�%�(#�,! ��!#�Q���8G0;* 0;-AK:�,0i=j-/%)%��,�)! _ �q-�2>%)(#�q�,uGC��,=#%� 1��!�h�K:�AC,-/8j26�n 1%9 ;2b%)(G�n��!#0"F =j-/%)%��,�)! %�(:-/% ;27h-/=#=:�A* *& ��d�,���,!&%�01F9K&F %)(#� �������)�ACY%g-/!:* � 8#0"�H7h-A=#=# 1!G�J2�-o��%��,���,=:�\C@(�� ���&c

v �b�)�oC,-/=�h# "%�(:-?2OK:�,�P!L-A�)�?8#�A*>%)(:-A%��,uGC��,=#%� 1��!j2�26(G��8#03* K:�D*&� �:!#�o*kQ� 1%�( ���A26=:�ACY%�%)�%)(#�'�)8G01�D-�C�%�8:-/0"01F>0"�A-/��!#�A*>K\F>%)(#�'!#�P%6QR����S c�ef%� ;2����P!#�,�@-A010"Fk!#�?%i=:� 2)26 "K#01�D%)� *&�,%��,�)7> "!#��,u#-?C�%)0"FLQ�(:-A%$��8#01� ->!#�,%�Q��?�)Sn(:-?2 01�o-/�)!G�A*�hlK#8#%D�,u#-A7> 1!j-/%) "��!:2g�/��0"�A-/��!# 1!G�L*\F&!:-A7> ;CP2C,-/!h�� "rJ�D-$���J�\*L 1!j*& ;C,-A%) "��!lc

�g��%)�gh<(#�AQ��,rJ�,��h4%�(:-/%b�,rJ�P! Q� 1%�( %�(#�h2� 17>=#0"�k%��@-A 1!# "!#�n%@-?26S *& 32)C�8j2)26�o* -/K:�ArJ�Uh���!#�C,-/!#!G��%�K:� a W � ] ` V;X Q�(# 3C ( �)8#0"�H(:-�2�K:�,�P!> 1!:*\8:C��A* ������7 %�(#�H%��@-/ "!# 1!G�b26�P%,c v (#�'!#�,%�QR���)S7h-,F (j-orJ�n0"�A-/��!#�A* - 7>����� C���7>=G01�,u -/0"%)�,��!:-/%� 1rJ�q%)� � �n%)(:-A%q26 17 10;-A�)0"F (:-/!j*&01�A2h-A010=:-/%�%)�,��!:2 �,uGC��,=#% _ � C��?�)���AC�%)0"FJc�� "%)(#�?8#%526�?7>�4QN-,FH�/�G 1!\%)�,��=#�)�P%) 1!G��%)(G�<Q��, "��(\%@2^h, 1!:*& "�)�ACY%7>�,%)(G�\*#2 2�8:C (D-?2 �,u#-A7> 1!G 1!#��%)(G� 0"�A-/��!# 1!G��Kt�P(:-,r& "��8#�lQ� "010A!#�,rJ�,�IC���!jC�018:2� 1rJ�,0"Fg*&�,%��,�)7> "!#�%)(#�' 1!\%)�P�)!:-A0t��8#!:CY%) 1�?!:-/0" 1%�F9�/�T- !#�P%6QR����S c

�#�?�)%)8G!:-/%��,01FUhJ������%�(#�'=#8#�)=:� 26�A2��/�R*\� �:!# "!#�b�,uGC��,=#%� 1��!j2%hJ 1%�%�8#�)!:2��?8#%g%)(:-A%���!#�D*&�J�A2!#��%qXtW@W��>%)�qS&!G�/Q �,uG-�C�%�01FnQ�(# 3C ( �)8#0"�>%)(#� !#�,%�Q��?�)S (:-�2$ "!:*&8:C��o* ���)�?7 %)(#� %)�@-A 1!# "!#�=#�)�\C��o2)2�c � (:-A%)�,rJ�,�R�)8#0"�H7h-A=#=# 1!G�bQ�-�2�0"�A-/��!#�A*�h# "!>%)(G�$CP-�26�'�A��%)(#� *#-/%.- "! v -/KG01�&c �Ch%)(# 3247h-/=G=# 1!#� *& ;*$!#�?%�(:-/!:*\01��=:-A%)%)�P�)! _ �iCY���)���AC�%�01F � %)(#�P�)�����?�)� _ �� ;2<-A!k�Pu#C��P=#%) "��!$Q� "%)(�)�A2�=t�oC�%�%)�b%�(:-/% � 8G01� � -/=#=G 1!#� � Q�(:-/%��,rJ�,�R 1%�7h-,F9Kt� �s-/!:*h%)(#� ���?�)�)�oC�% � -/=#=G 1!#�Gc

ef%� 32���!h%)(# 32�K:-�2� ;2�%)(:-A%ge =#����=:�J2��9*&� �:!G 1!#�b�,uGC��,=G%) 1�?!:2 "!q-bC���!#!G�AC�%) "��!# 326%gC��?!&%��,u\%-�2i%�(#�J2��k=:-A%)%��,�)!:2������HQ�(# 3C (q%)(#�P�)�$ 32H->*& 32)C����,=:-A!:C�FhK:�,%�Q��,�,!q%)(#� � 8#0"� � -/=G=# 1!#� f -�2 17>=#0"�,79�,!J%)�A*>K\FL%�(#�b!#�,%�Q��?�)S -/%D->�� 1rJ�P!L%) "7>�9] MJh5-/!:*n%)(#� �������)�ACY% � -/=#=G 1!#�Gc v (:-/% ;2%h�W�� a W _ ]fV �JX ^ V;X ` XtW@] � � � �q`�� W'];U � ^ W _#` ]�]�W � X ^ � UGV a U ��W � W X ��] b`�_J_ W�� a � ��� W a ] � � � �] U:WDXtW.] � � � �s` ] ` �JV �/WYXn]fV W']^h#�� "rJ�,!h2���7>�D*&� �j!# 1%� 1��! �/� � C������)�AC�% �1c

v (G��*&� �j!# 1%� 1��!'�A�#�,uGC��,=G%) 1�?!:2 %)(j-/%5 ;2 %)(G�,�)�����?�)��=#����=:�J2��A*$ 1!D-gC���!#!G�AC�%) "��!# 326%5C��?!&%��,u\% ;2�rJ�,��F>2� 17> "0;-/��%��b%)(#�'���P!#�,�@-A05*&� �:!G 1%) "��!>�? 1rJ�,! 1!q26�ACY%) 1�?! &c � �<��!#0"F>%)(G� "!:26%.-/!\%) 3-/%) "��!�/�R%)(#� � Z � W � `�_J_ V;X��$ 32O!G�/Qwhd 1!n%)(G ;2gC���!\%)�,u\%)h:%)(G�b7h-/=#=G 1!#�9 17>=G01�,79�,!J%)�o*kK&Fq->CY��!#m

Page 125: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

!#�AC�%� 1��!G ;26%R!#�,%�Q��?�)Sh-A%H-$�? 1rJ�,!h=:�� "!&%g*\8#�) "!#�b%)�.-/ 1!G 1!#�Gc

� ��� ��� � � � � � � � � � � ���'+� � ������� � �H� � ����

v (#� �E26%.-/!:*G-/�@*��/ 3*&�A-��/�j�,u#CY�,=#%) "��!:2^h,K:��%)(D 1!'%)(G��=:2�F#C@(#��0"���? ;C,-A0J-/!j*$C��?��!# "%) 1rJ��7>�\*\�,010" 1!#�C���!\%)�,u\%@2^h&(:-?2�K:�,�,!h%)(:-A%�%)(#�PFh-/���$- ^ ] ` ]xV a �?�)�?8#=L�A�< "%)�,7h2 �J��!#�DC,-A!L2�=:�AC� ��F9%)(G�$2��,%��/��,u#CY�,=#%) "��!:2g 1! -s7s-/=#=# "!#�>%.-�26S f 268:C@( -�2 =G�)��!G��8#!:CY 1!#� �T!G��01 326( Q��?�@*#2^h �?�$�?�,!#�,�.-/%) "!#�%)(#�, "��=:-�2�%�%)�,!:2��i������7h2 M5 "!h-�*&r?-A!:C��UhG-/!:*>!#�9C@(:-/!G���H "!h26�,%R7>�,7bK:�,�.26(# "=b ;2 %�(#��8G��(\%�%)��\C,C�8#� f -/0"%)(#�?8#��( %�(#�,�)�97h-,FnK:�h26�?7>� *& ;2�-/�����,�,7>�P!&%HK:�,%�QR�,�,! �)�A2��A-/�.C (#�P�@2'-/K:��8G%b%)(#�=#�)�ACY ;26� -L=#�� 1���� �2��,%$7>�P7kK:�,�.26(# "= �526�,�h2��AC�%� 1��!j2 � c �#c �L-/!j* � c �Gc � ����� -L�)�,r\ 1�PQ �/�+%)(G ;2 ;2)2�8#��M.c

�#�?�4�,uG-/7 =#01�UhY%)(#�R=:-�2�%)m�%)�,!j26��7h-A=#=# 1!G���/� ��� �����h%)� ������� �> ;2 "!&r?-A�) ;-AK#01F C���!:2� ;*&�P�)�A*%)(#�H�Pu#C��P=#%) "��!�h\-/!j* %)(G�H7h-/=G=# 1!#�D�/� � ��� �L%)� � ��� ����� 32 !#�?%,c �H2�*& 32)C�8j2)26�o* -AK:�/rJ�gh&%)(G ;2C,-/%��,���?�) � -/%) "��!D ;24K:-?26�A*$�?!b%)(#�R 17>=G01 ;CY 1%d-�2�268#7>=G%) 1�?!$%�(:-/%<%�(#��2�F#2�%)�,7�8#!j*&�,��*& 32)C�8j2)26 "��!(:-�2� 17>=G01�,79�,!J%)�o*$%)(#� �E-?*#* � *��$�)8G01�Jc

v (G ;2<C��?!:C��,=G%4(:-?24K:�,�,!D 1!&���,0" ;C� "%)�?8:260"Fi%��@-/!j26=#03-/!\%)�A*$%��H%)(#�NC���!\%)�Pu&%5�/�IC��?!#!#�AC�%� 1�?!# ;2�%01�A-A�)!# "!#�H2�F#2�%)�,7s2%h,Q�(#�,������!#�gC,-A!#!#�?%)h�%�F\=# ;C,-A010"FUh,*&�P%)�,��7> 1!#�5 1! -�*&r?-A!:C���Q�(G ;C@($7h-A=#=# 1!G�%)(#�9!#�,%�Q��?�)SqQ� 1010B01�A-A�)! f "%' ;2H-A0;26� y8G�A26%� 1��!j-/K#0"�bQ�(#�,%)(G�,�'��!#� C,-/! =#���A*& ;CY%HQ�(:-/%D�)8#0"�UGZ b` X ^ 01�A-A�)! �g26�P� ��(:-A=#%)�,� � M.c e�%9(:-?2 K:�,�,!�-/����8#�A* %�(:-/% - 2��,!:26 "K#01�q*&� �:!# 1%� 1�?! �/��,u#CY�,=#%) "��!:2� "!h%)(#�DC��?!#!#�AC�%� 1�?!# ;2�%gC���!\%)�,u\%� ;2�Q� 1%�(h�)�A2�=t�oC�%�%)�9%)(#� f ��8#01��M�7s-/=#=# "!#�$%�(:-/%%)(#�9!#�,%�Q��?�)S (:-�2' 1!:*\8:C��A*L���)�?7 %�(#�k%��@-A 1!# "!#�n2��,%)hB-/!:* 17 =#01�,79�Y!&%��A* "![%�(#�>!#�,%�QR���)SQ��, "��(\%@2�c

e �:�?!#�gC,-A!#!#��%�=#���A*& 3C�%l%)(#��7s-/=#=# "!#�g%)(:-A%<%)(#�R!#�,%�Q��?�)SD01�A-A�)!:2^h/%�(#�,!b��!G�g-/0;2��'C,-A!#!#��%=#�)�A*\ ;C�%H%�(#�926�P% �A���,uGC��,=G%) 1�?!:2i%�(:-/%DQ� 1010B-/�� ;2��Jc v (# ;2'26�P% f -/!:* %)(#�b0"�A-/��!#�A*n7h-/=#=G 1!#�\MC,-/! *\ ��d�,�b*\�,=:�,!:*& "!#�L�?! %)(#� !#�,%�Q��?�)S -/�.C (G 1%)�oC�%)8#���Uhl%)(#� 01�A-A�)!# "!#�L=#���\C��A*&8G�)� f Q�(# ;C@( 1!:C�0"8:*&�A2$%�(#�h01�A-A�)!# "!#� -/0"���?�) 1%�(#7uh�%)(#�h�,���)�?� ��8#!jC�%) "��!�h�%)(#�h�?�@*&�,�9�/� =#�)�A2��,!\%@-/%� 1�?! �/�=:-/%�%)�,��!:2%h\%)(#�H0"�A-/��!# 1!G�$=:-A�@-/7 �,%)�,�.2%h\-/!j* 2��b��! MJh:-/!:*>%�(#�H 1!G 1%) 3-/0d26%.-/%��H�/�B%)(#�+!#�,%�Q��?�)Sdc�TrJ�P! E��%�Q��9 ;*&�P!&%� ;C,-A0l!#�,%�Q��?�)SG2i-A�)�$%��@-A 1!#�A*h��!n 3*&�,!\%) ;CP-/0 =j-/%)%��,�)! 2��,%@2^ht%�(#�,FqC,-A!n26%� 10"0*& ��d�,�g 1!hQ�(:-A%H7h-/=G=# 1!#�b%�(#�,F> "!:*&8:CY�Uh:-/!:*h%)(#� 26�,%g�/�T�,u#CY�,=#%) "��!:2�%��k%�(:-/%+7h-/=#=G 1!#�?h& �%)(#�,Fs26%@-A�)%�������7 -b*& ��d�,���,!\%g26�,%��A�< "!# 1%� ;-/0dQ��, "��(\%@2Yc

�g!#�D2�%)�@-A!#���9-A!:* =:�,��(:-/=j2iC��?8#!\%)�,�� 1!\%)8# "%) 1rJ�����A-A%)8#��� �A�R268jC ( -k*&F\!:-A7> ;Cg*&� �:!G 1%) "��!

Page 126: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

���� ��� � ������������� � � �

;2 %�(#� � W �E` ]xV �,V1] � �A�<%�(#�'C��?!:C��,=G%��/�B�,uGC��,=#%� 1�?!:2< 1!q-$C��?!#!#�ACY%) 1�?!# ;2�%�=:-A�@-?*& 1�?7nc!�<-/%�%)�,��!:2-/�)�b!G��%H�,uGC��,=G%) 1�?!:2� 1! -/!j* �A��%�(#�,7h2��,01rJ�o2%h&KG8#%H��!G01FL���,0;-A%) "rJ� %��h%)(#�D7h-/=#=G 1!#�>%�(:-/%+ ;2 17>=#0"�,79�,!J%)�A*HK\Fb%)(#��!G�,%�Q�����S9*&8#�� 1!#�D-'26=:�AC� �dC�01�o-/�)!G 1!#�'%)�� ;-A0 �\-�2<Q��P010:-?2TQ� "%)(9�)�A2�=:�AC�%%)�>%�(#�b%) "7>�9]�-/%HQ�(# 3C (n%�(#�,Fq-/���b0;-AKt�P0101�o*�hl-/!j*n-/0;2��hQ� 1%)(n���A26=:�ACY%H%)�>%�(#�9C��?�)�)�oC�%)!#�o2)2C��) "%)�,�� 1��! %)(:-A%i 32�8:26�A*>%��>*&�P%)�,��7> 1!#��%�(#�D26�,%��A�� 1!jC������)�AC�%R=:-/%�%)�,��!:2g-/%�%) "7>�b]�c

ef!9-H0;-A%)�,�T26�AC�%� 1�?!�hJe5*& ;2�C�8:2)25%)(#��=#����K#0"�,7 �A�l%�(#�g-�*&� y8:-?C�F$�A�l%�(#�g*&� �:!G 1%) "��!b�A�lCY��!#m!#�AC�%� 1��!G ;26%��,uGC��,=G%) 1�?!:2%hJ���,0;-A%) 1!G� "%�%)�$%�(#�H=#����K#0"�,7��/�5%��@-A!:26=#03-/!\%) "!#�b%)(#�g8:2�8:-/0IC���!:CY�,=#%�/� � �,uGC��,=#%� 1�?!:2 �\%)�b%)(G�$CY��!#!#�oC�%) "��!# 326%�=:-A�@-�*\ 1��7 c

����� �� �� � � ����� �

e�! %)(G ;2'26�ACY%) 1�?! ei�)�Pr& "�,Q�%)(#�9=#�@-?C�%) 3C,-/0R-A!:* %�(#�,�?�)�,%� ;C,-A0< 17>=G01 ;CP-/%) "��!:2��/�g8G%) 10" � "!#�9%)(#�*&F&!j-/7> 3C�*&� �:!# "%) "��!9�/�B�,u#CY�,=#%) "��!:2< "!>C��?!#!#�ACY%) 1�?!# ;2�%��,u&=:�,�� 17>�P!&%.-/%) "��! � 26=:�AC� �dC,-/0"01FUh?%)(#� 17>=:-?C�%g%)(:-A%$%)(G�A26�9 ;*&�o-�2H(:-,rJ�k�?! %)(G�>2��A-/�.C (n�����D-L*\8:-/0��)�?8#%)� 1! %)�@-A 1!#�o* !#�P%6QR����S#2Yce�! %)(#�q!#�,u\%>2��AC�%� 1��!�26 "7k8#03-/%� 1��!j2$-/��� C���!j*&8:C�%��A* %�(:-/%>%.-/SJ�h%)(G�A26�q 17>=#0" ;C,-A%) "��!:2' 1!\%)�=#�@-?C�%) 3C,-/0I-�C,C��?8#!\%,c

v (G�"�:�@2�%i7h- �����g 17>=#0" ;C,-A%) "��!hC��?!:C��,��!:2�%)(#� W@] U � ��� � ��� � 8:26�A*hQ�(#�,!n%��)F\ 1!#�9%)�h*\�,m%)�,��7> 1!#��%�(#���,u\ ;26%��,!:C��R�/� -H*&8:-A0t����8#%��Jc<e �d��!G�i8:2��A2<%)(#�g*\F&!:-A7> ;C�!#��%� 1�?!b�/�l�Pu#C��P=#%) "��!:2^h��!#�hCP-/!#!#�?%926=:�AC� E��Fn 1! -?*&r?-/!:CY�>%)(#�s26�,%D�/�g�,uGC��,=#%� 1�?!:2%hB-/!:* (#�,!jC��>CP-/!#!#�?%bK:-�2��h26%.-/m%) ;2�%) 3C,-/0g-A!:-/0"F#2��A2k���901�o26 1�?!# 1!G� 2�%)8:*& "�A2b��! 268jC (�- C�0;-?2)2� �dC,-A%) "��!lc � -/%)(G�,�)h��?!#�L798:2�%��K:2��,�)rJ�'01�o-/�)!G 1!#�b "!L�A-?C (h 1!j*& 1r\ ;*&8j-/0l!#�,%�QR���)S,h#-A!:*L��!q�A-�C@(h=:-/��%) 3C�8#0;-A��01�A-A�)!# "!#�9%)�) 3-/0Xh%)�9*&�,%��,�)7 1!#�g%)(#�D2��,%��/���Pu#C��P=#%) "��!:2�%)(:-A%H-A�) ;2��D*&8#�) "!#�b%)(j-/%g%)�) 3-/0xc

�g!:CY� %)(#� �,uGC��,=#%� 1��!j2[(:-,rJ� K:�,�,! ;*&�,!\%) �:�A*� 1! %)(# 32[7h-/!G!#�,�)h>%�(#� 268GK:26��J8#�,!\%7>�,%)(G�\*&��0"����F 32>%)(#� 2)-A7>� -�2k����� - =#�) "���) '�,uGC��,=G%) 1�?!:2�c �g!#� C,-/!�-/%�%)�,7 =#%>%)� �:!:*�,r& 3*&�,!:CY�i�����H%�(#�$�Pu& 326%)�P!:C��'�/�N->*&8j-/05�)��8G%)�bK\F 0"�A26 "��!# "!#�9%)(#�D!#�,%�Q��?�)Sq26FG26%��,7h-/%� ;C,-A010"Ff -�2��)�Pr& "�,Q��A*9 1!���(:-/=G%)�,���&MJht�?�iK\F>�,uG-/7> "!# 1!G�$%)(G� "!&%��,�)!j-/0526%��)8:CY%)8#��� �A��%)(G�$!#�,%�QR���)Sf ��(:-A=#%)�,� �yM.c

� 2��AC��?!:*$ 17>=G01 ;CP-/%) "��!DC��?!:C��,��!:24(#�AQ =G�)�,r\ 1�?8:2<26%�8:*& "�A24 1!\%)�+�,u#CY�,=#%) "��!D01�A-A�)!# "!#�'-/!j*%)(#�'�,u\ ;2�%)�,!:CY�H�/�T-kCY��!#!#�oC�%) "��!# 326%g*&8:-A04����8#%��D-/�)�D%)�bK:� f �)�,m�Mf�Pr�-A018:-A%)�A*,h# 1!h%)(#�'0" 1��(\%��/�%)(#� -/����8#7>�P!&%.2i�� "rJ�,! -/K:�ArJ�k�����'%�(#�k!G�AC��A2�26 1%�Fq�/�g*\�,%)�,��7> 1!G 1!#�9%)(#� 26�P% �A�g�,uGC��,=#%� 1��!j2*&F&!j-/7> 3C,-/0"01FJc �J8:C@( 26%)8j*& 1�A29(:-,rJ� %�F\=# ;CP-/010"F *\� �:!#�A* �,uGC��,=#%� 1��!j2 Q� "%)( ���A26=:�ACY%k%�� -A!

Page 127: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

- =G�) 1�?�) H��8#01�ghi-A!:* (:-,rJ�L!#�?% %.-/SJ�,! 2�%)�,=j2 f �, 1%�(#�,�9%)(#����8#�?( �?K:26�P�)r?-/%� 1��! �/� 01�A-A�)!# "!#�*&F&!j-/7> 3C,2H���$K\F -/!:-A01FG26 ;2'�/�+%)(#���:!:-/0RQ��, "��(\%@2@MH%)�qrJ�,�) E��Fn%)(:-A%$%�(# ;2'�)8#0"�>Q�-?2$ 1!:*&�P�A* 1!:*&8jC��A* K\F %)(G�[!#�P%6QR����S ���)�?7 %)(#� %)�.-/ "!# 1!#� 26�,%Pc g "rJ�,! %)(:-A%h!#� rJ�,�� �dCP-/%) "��! Q�-�28#!:*&�,��%@-ASJ�,!�hd-/!:*n%)(:-A%H%)(G�,�)�9-A�)�b8:2�8:-/0"01Fq-k0;-A�)�?�b!&8#79K:�,�g�/�R=:�J2)2� 1K#0"�b7h-/=G=# 1!#� 2O%�(:-/%- !#�P%6QR����ShC���8G0;* 0"�A-/��! ������7 -/!\F>�� "rJ�,!h%)�.-/ 1!G 1!#� 26�,%�ht�?!#�bCP-/!#!#�?%HK:�bC��P�)%@-A 1!h%)(j-/%g%)(#��,u&=:�ACY%)�A*[��8#01� Q�-�2$0"�A-/��!#�A*�h�-A!:* (#�,!:CY�>%)(:-A%b%)(#�h�,u\=:�AC�%��A*[2��,%b�/�+�,uGC��,=#%� 1�?!:2$-A�)�J2��Jc�i!&F -/!:-A01FG26 32T�A�l%�(#�i!G�,%�Q�����SbQ�(#�J2��ir?-A01 ;*\ 1%�F$QN-�2<=#�)�o*& ;C,-A%)�A*b��!9%)(G�i�,u\ ;2�%)�,!jC����A�B- 2��,%�/� f -b=#�) "���) �M��,uGC��,=#%� 1��!j2 Q��?8#0;*>K:�$�?!L8#!jC��,�)%.-/ "!>������8#!:*dc

v (G ;248#!jC��,�)%.-/ "!&%�FH7h-,FH�?�'26�?7>��QN-,F %��AQ�-/�.*#24�,u\=#03-/ 1!G 1!#� � U � =:-�2�% � � �?�)%.24%)�'*\�,%)�ACY%*&8:-/0+�)��8G%)�A2> 1! !G�,%�Q�����S#29(:-,rJ� �x-/ "01�A* � K:�ACP-/8:2��[%�(#� 26�,%.2k�/� �)�,�?8#0;-A�h-/!j* �,uGC��,=G%) 1�?!=:-/%�%)�,��!:2 b` � (:-,rJ�'Kt�P�,!h 1!:C��?�)���AC�%)0"Fb0;-AKt�P0101�o* c

� %�(# 1�.*�hd-/!:*n=:��%)�P!&%� ;-/0"01Fh7>�?�)�D26�,�� 1�?8:2%h "7>=#0" ;C,-A%) 1�?!qC,-/!nK:�b�@-A ;2��A*L 1! -�* ��8#!jC�%'%)�%)(#�+26�ACY��!:* c�ef%�CY��!:C��P�)!:2<%)(G�i7>� 26%RC��?!&r\ 1!:CY 1!#�H�Pr& 3*&�,!:C�������8#!j*>26�'�x-/�<�����R%)(#�g�,u\ ;26%��,!:C���/�R->*\8:-/0<����8#%��$ "!L!#�,8G�@-/05!#�,%�QR���)SG2%h:!:-A7>�,01F ��8#0"01 1!j-/�) 3-b-/!:* ��(j-/%)�P� � 2 f �������yM+*&��8GK#01�*& ;2�26�\C� 3-/%) "��!>���A268G01%,c � �AC,-A010:%)(j-/%)hG-�2�*& 32)C�8j2)26�o*k 1! ��(:-/=G%)�,� �?h���8#0"01 1!j-/�) 3-'-/!:* ��(:-A%)�,� � 2���,�A*y���?�)Q�-A�@*>!#�,%�QR���)S 268 � �P�)�A*h*& 326=:-A�@-/%��b*#-A7h-/�?�H%)�b "%@2�-AK# 10" 1%�Fk%��9C������)�ACY%)01F97h-A=>�)�,�?m8#0;-A�'-/!:*n�,uGC��,=#%� 1�?!n=:-/%�%)�,��!:2H-o��%��,�'01�A2� 1�?!# 1!#�Gc ���oC,-/8:2��b%)(# 32H*&�?8#K#01�9*\ ;2)2��\C� ;-A%) "��! Q�-�2*&�,7>�?!:26%��@-/%��A* ��! - 26 "!#��0"�L%)�.-/ "!#�A* !#�,%�Q��?�)S,h�%)(G� ���A268G01%9=#�)�Ar\ ;*&�A* 7>�?�)�qC��?7>=:�,010" 1!#��,r& 3*&�,!:CY�i������%�(#�$�,u\ ;2�%)�,!jC��H�/�T-9*&8:-/05�)�?8#%)�D%)(:-A!L(:-?* (# "%)(#�P�)%)�bK:�,�P! ����8G!:* "! (\8#7h-A!26%)8j*& 1�A2Yc

�g�/QR�,rJ�,��h E�� "%$Q�-?2 ���?8#!:* %)(:-A% ��8#0"01 "!:-/�� ;-h-/!:* ��(:-/%��,� � 2 f �������yM C�0;-?2)26 �dC,-A%) 1�?! �/��)�,�?8#0;-A�$-A!:*n�,u#CY�,=#%) "��!q=:-/%�%)�,��!:2H(:-�*[K:�,�P!nK:-�2��A* �?! %)(G�9-�2)2�8#7>=#%� 1�?!n%)(:-A%b-hC��,��%@-/ "!� �)8G01� �:Q��?8#0;*LK:�b01�o-/�)!G�A*LK&Fq%)(#�b!G�,%�Q�����S�hI-/!:*n 1%HQN-�2H�A2�%@-/KG01 ;2�(#�A*L%�(:-/%'%)(G ;2i��8#01�DQ�-�2!#��%�0"�A-/��!#�A* f -/!:*>%)(j-/%�-b*\ ��d�,�)�P!&%N26�,%R�/�T*&F&!j-/7> 3C��,u#CY�,=#%) "��!:2R-/���J26�D*&8G�) 1!G�b01�A-A�)!# "!#�&MJh%)(#�,! %)(# 32�:!:*& "!#�nQ��?8#0;* CP-�26%9*\��8#K#%9��! %�(#�h26 "��!# �dC,-A!:C��>�A�H%�(#�, 1�D�)�A2�8#01%Pc � *&��8GK#01�*& ;2�26�\C� 3-/%) "��!b7h-,FUhA2���7>�P(#�AQwh/(:-,rJ�RKt�P�,! ���?8#!:*$K:�,%�Q��,�P!$%�Q��+26�,%.24�/�d=:-A%)%��,�)!:25%)(:-A%<Q��,���X ��]t���,��8G0;-/�.2�-A!:*k�,uGC��,=#%� 1�?!:2 f 26�?7>�g=t� 2)2� 1K#0"�H�,u\=#0;-A!:-/%� 1��!j2T�A�5(#�AQ 268:C@(h-'�)�A2�8#01%RC��?8#0;*-/�) 326� -/���h*& ;2�C�8:2�26�A*n0;-A%)�,�YM@che � ��8#0"01 "!:-/�� ;->-A!:* ��(:-A%)�,� � 2 f ����� �JM'�)�A2�8#01%' 32$*& 32)C����A*& 1%��A*�h%)(#�,!9%)(G�i�,r\ ;*\�,!:C������?� %�(#�g�,u& 326%��,!:C����A�B- *\8:-/0d�)��8G%)�g 1! C���!#!G�AC�%) "��!# 326%�!#�,%�QR���)SG2<Q��?8#0;*Kt�oC���7>� 26�,rJ�,���,01FbQR�A-/SJ�P!#�A* c

Page 128: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� ����� ����������� � � ���

����� � � � � � � � � �%����� � � � � � � � � �� � ���������

��������� �jR��� ��� ���l� � �Oe�!n%�(# ;2+26�AC�%� 1�?!�hle��,u&=G01�����$%�(#� _ �)`Ja ]xV a@` � -�2�=:�AC�%@2H�A��8:2� 1!#�>%�(#�9*&F\!:-/7 ;C !G��%) "��! �/�R�,u\mC��,=#%� 1��!j24Q�(#�,!9 1!\rJ�A26%� 1� -/%) "!#�H%�(#���,u\ ;26%��,!:C��R�/� - *\8:-/0:�)�?8#%)�� "!>-'C��?!#!#�ACY%) 1�?!# ;2�%�26FG26%��,7ncv (# ;2�!#��%� 1��!h�,!\%@-A 1032 2���7>�g=#�.-�C�%� ;C,-A0t=G�)��KG01�,7h2 �l!#�b01�?!#���,�R ;2�%)(#�+26�,%R�/�B�,uGC��,=#%� 1��!j2T "!h-%@-�2�SbQ��,0"01mx*&� �:!G�A* �� "%�C,-/! *& � �P�4���)�?7�%)�) 3-/0#%��'%)�) 3-/0Xh&-A!:*b%)(#�� 3*&�,!\%) �tC,-/%� 1��!b�A�l�,uGC��,=G%) 1�?!=:-/%�%)�,��!:2< 1!9��!#� ^�_ W a V � a 01�A-A�)!# "!#�H%)�� ;-A0t 324!#�AQ -A0;2��b*&�,=:�,!j*&�,!\%<��!9r?-/�) "��8:2R-�2�268#7>=G%) 1�?!:2-/!:*qC (#�? ;C��o2�c

ef! %�(#� �,7 =# 1�� ;C,-A0'26%�8:*&F�*&�A2)CY�) 1K:�A* 1! %�(# ;2q26�AC�%� 1�?!�h$e>���,=#01 3C,-/%�� ��8G0101 "!:-/�� ;- -/!j*��(:-/%��,� � 2 f �������yM !#�,%�Q��?�)S -/!j* %��@-A 1!# "!#� =#���\C��A*&8G�)� f (#�,!:C��Y�����)%�(�hh%)(#��CY��!\%)�@-?C�%) "��!� � � � � �lQ� 1010�K:�>8:2��A*[%��L�)�Y���,�'%)�L%�(#�>=:-A=:�,��M.c v (#���:�@2�%$%@-?26S 32H%)�n*\�,%)�,��7> 1!G�bQ�(# ;C@(=:-/%�%)�,��!:2<Kt�oC���7>�R�,uGC��,=#%� 1��!j2<*&8#�� 1!#�'%)(G�i%��@-/ "!# 1!G�H=#�)�\CY�A2)2 �&%)(G ;2< 1!\rJ��0"rJ�A2 7h-/S\ 1!G�H=#�@-A��m7h-/%� ;C�*&�AC� 326 "��!:2<-AK:��8#%R%)(#�NC������)�AC�%�!#�A2�2<C��) "%)�,�� ;-�%)�'K:��8:26�o*�h\-/!:*$%�(#��%) "7>��=t�? 1!\%R*&8#�) "!#�%)�@-A 1!# "!#�9-/%gQ�(# 3C (>=j-/%)%��,�)!j2i-A�)�D*& 1r\ ;*\�A*k 1!\%)�92��,%@2��/�B�)�P��8#03-/�@2g-/!j* �,uGC��,=#%� 1�?!:2�c

�g!:CY�L%)(G�nC�03-�2)2� �dCP-/%) "��! ;2b7h-�*&�gh %�(#�L7>�P%)(#�\*&�?01�?��F ���?�>*\�,%)�ACY%) 1!G� - *&8:-A0H�)�?8#%)��)�,7h-A 1!:2�%�(#�b2�-/7>�D-?2H*& ;2�C�8:2�26�A*h 1! ��(j-/=#%��,� �\cHef%g ;2��,u#-A7> 1!G�A*kQ�(#�,%�(#�,�g%)(#�'=:-A%)%��,�)!:2%)(:-A%HK:�AC,-/7 �$*\F&!:-A7> ;Cg�,u#CY�,=#%) "��!:2g*&8#�� 1!#�9%)�.-/ "!# 1!#�s-/�)�D 1!\%)�,�?�@-A%)�A*q26�A-A7>01�A2�260"FkK\Fh%)(#�!#�,%�Q��?�)S,h����RQ�(#�,%)(G�,��%)(#�,F$���?�)7�%�(#�, 1�B�/Q�!s*& ;2�%) 1!jC�%�268GK#mfCY0;-�2�2 "!k%�(#�i!G�,%�Q�����S � 24(# 3*#*&�,!8#!# 1%R2�=:-�C�� � -�2 !G��%)�o*k 1! ��(j-/=#%��,� �+h#- =G�)�,����y8G ;26 "%)�����?��%)(G�H�,u\ ;26%��,!:C����A�B-$*&8j-/0 ����8#%��Jc

v (G� � � ���s%.-�2�SnQ�-�2'C@(#�J2��,! -�2H%�(#�>2�8#K����AC�%+�/��%�(# ;2g�)�,=#0" ;C,-A%) "��!nK:��%�( ���?� "%@2H2� 17>m=#01 3C� 1%�FD-/!:*9 1%@2�2� 1��!G �dC,-A!:C��Jc v (#�g!#�,%�Q��?�)S f Q� 1%�(�� (# 3*#*&�,!98#!# "%@2 M5 32B�x-A��2�7h-/0"01�,�5%)(:-A!�h�����'�,uG-/7>=#0"�Uh:%)(#��� ���/m�(# 3*#*&�,!#m�8#!# "%$QR���@*n�)�o-�*& "!#�L!#�P%6QR����SL�/� �<0;-/8G%$-A!:* � C���01�,0"0;-A!:*f ����� �JM f 2�%)8:*\ 1�A*' 1!���(:-A=#%)�,� �JMRhJQ�(# ;C@($7s-/SJ�A2l 1%501�A2�24=#����K#0"�,7h-/%� ;C<%)�D-A!:-/0"F#2��Jc �#8#��%)(#�,��m7>�����Uh ��8#010" 1!:-A�) 3-k-A!:* ��(:-/%��,� f ����� �JMg0;-/K:�,0"01�A*h%)(#�P 1�g=:-/%�%)�,��!:2H-�CPC����.*& 1!#� %)�h-hC��?!:C� ;2���)8#0"�UhlQ�(# ;C@([QN-�2$03-�C@S& "!#�> 1! %)(#� �<0;-/8G%b-/!j* � C ��01�,0"0;-/!j* f ����� �JMD26%)8j*&F �<%�(#�h2��,%'�/� f -=#�) "���) �M��,uGC��,=#%� 1��!q-A!:* ���,��8#03-/�g=:-/%�%)�,��!:2i 32�C�01�A-A�)0"Fh*&� �:!G�A*h-/!:*L�A-?26Fh%)� C��?!&%��@-�2�%iQ� "%)(%)(#�N*&F&!j-/7> 3CT�?�)�?8#=# 1!G�J2�c �5 1!:-A0101Fgh,%)(#�N26�,%<�A�d%)�@-A 1!# "!#�g=:-/%�%)�,��!:24 ;2l�)�P0;-/%� 1rJ�,0"FH2�7h-/0"0 f � ��yMQ�(# ;C@(b7h-/SJ�o2 "%<=:�J2)2� 1K#0"��%)�'�,uG-/7> "!#��-A!:*b�)�,=#���\*&8:C����?�@-A=#(:2 �A�l%�(#��Q�(#��0"�i%��@-A 1!# "!#�'26�P%)h 1!:2�%)�A-?*s�A�R267s-/010d2�8#K:26�P%@2�c

Page 129: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� �� ����������� � �������������������������� ������������������������������������

v (G� ^ V �JXGV � a@` X a W<�A�5%)(#� � � ��� %@-?26Sb 32T%�(:-/%� "% 324%)(G�HC��?!#!#�ACY%) 1�?!# ;2�%�26FG26%��,7�%)(j-/%�(:-�2*& ;2�=#0;-,FJ�A*b%)(#� 26%)����!#�?�A26%��Pr& 3*&�,!:C��g�/�T*&�,rJ�P01��=G 1!#�D-b*&8:-A0 ����8#%���� ��8#010" 1!:-A�) 3- -A!:* ��(:-/%��,�f ����� �JMO���?8#!:*n->*\��8#K#0"�b*& 32)2��\C� ;-A%) 1�?!nK:�,%�Q��,�,!h���,��8#03-/�'-A!:*L�,uGC��,=#%� 1�?! =j-/%)%��,�)!j2i 1!q%)(#�01�A2� 1��!G�A*[!#�,%�QR���)S,h4Q�(G ;C@( 2�%)�)�?!#��0"F 268G�����o26%@2 � �N��!#�q2�8#K:2)CY�) 1K:�A2$%��L%�(#�h*& 32)26�\CY ;-/%� 1�?!7>�,%)(G�\*&��0"����F��q%)(j-/% f -s=G�) 1�?�) �M����,��8#03-/�'-A!:*L�,uGC��,=#%� 1�?!L=:-A%)%)�P�)!:2'-/���b(:-/!j*&01�A*LK\Fh%�Q��26�,=:-A�@-A%)�$7 �AC (j-/!# 3267 2T "!:26 3*&�H%�(#�'!#�,%�Q��?�)Sdc

g "rJ�,!'%)(:-A%<el-A7 8j26 1!G�i7>�?�)�R*& "�)�AC�%�hA26%.-/%) 326%� ;C,-A0&%��AC (G!# *J8#�A2:%)�'*& 32)C��ArJ�,�d�,r\ ;*&�,!jC��<�����-i*&8j-/0J�)�?8#%)� f -?24*&�o2)C��� 1K:�A*H 1! ��(:-A=#%)�,� �yM ��%)(j-/%Be -/7�8:26 "!#�H-g*&� �j!# 1%� 1��!'�A� � ���,��8#03-/� �,-/!j*� �,uGC��,=#%� 1�?! ��=:-A%)%)�P�)!:2�%)(:-A% f "%�(:-�2�Kt�P�,!h-/����8#�o*tM< 32 7>�?�)�g-/=G=#�)�?=#�) 3-/%)�+%)�9C��?!#!#�AC�%� 1�?!# ;2�%!#�,%�Q��?�)SG2 �<-A!:* %)(:-A%beH-A7 -A=#=#0"F& "!#�LK:��%�( %)�oC (#!G *J8#�A2i%��n-n26 "7>=#0"�$!#�,%�QR���)Sn%�(:-/%D(:-�2*& ;2�=#0;-,FJ�A* %)(G�n26%��)�?!#���A2�%>�)�P=t�?�)%��A* �,r\ ;*\�,!:C��h2��[�x-/� �/�DC��?!:26%��)8:CY%) 1!G� - *\8:-/0g�)�?8#%)�UhNeC���!\%)�,!j* %�(:-/%�%�(# ;2R26 1798#03-/%) "��!b�? 1rJ�A2<%)(G� � W ^ ]!� _J_ � � ]fZ\X#V1] � ^ � � `�� �A�B-b*&8:-/0d�)�?8#%)�HK:�, "!#�*&�,%)�oC�%)�A*9 1!q-kCY��!#!#�oC�%) "��!# 326%�!G�,%�Q�����S c

��������� ����������� �@�@+� � ����� ��+�<��� ��� ������ ��>� � �

�4 1�.26%)hG-k2�(#����%i�ArJ�,��r& "�,Q �A��%)(G�$*\�,%@-A 10;2��A�<%�(#� � � � �b%@-?26Sdc��8G0101 "!:-/�� ;-g-/!:* ��(j-/%)�P� f ����� �yM5=#����=:�J2��A*>-H2� 17>=G01���,uGC��,=#%� 1��!D%@-?26S$Q�(G�,�)�g-H!#�,%�QR���)S

01�A-A�)!:2�%��b7h-/=>=j-/%)%��,�)!j2O�A� � f K# 1!:-A�)F:MR*& 1�? 1%.2�%)�b��8G%)=#8#%g=:-A%)%)�P�)!:2��A� � f K# "!:-/��FtMR*\ 1�� "%@2Ycv (# ;2�7h-A=#=# "!#�b ;2�-?C (# "�,rJ�A*br& 3-b- (G ;*#*&�P! 03-,FJ�,���A� � (# 3*#*&�,!h8#!G 1%@2 �:26�,� �4 "��8#����&c �#c

0 0 0 0 1 1 1 1

0 0 0 0 1 0 0 0

�4 1�?8#�)��\c � � v (#� ��8#010" 1!:-A�) 3-k-A!:* ��(:-A%)�,� f �������yMi���P�A*y������Q�-A�@*n!#�,%�Q��?�)S,h Q� 1%�((�> 1!G=#8#%8#!# 1%.2%h � L(# ;*#*\�,! 8#!# "%@2D-/!:* �L��8G%)=#8#%b8G!# 1%.2�c v (#�h*&�P!:26 "%6F �/� 26(j-�*& "!#�n��! %)(G�>8#!# "%@2C������)�A2�=t�?!:*#2�%)�9%)(#�'0"�,rJ�,0:�/�R-?C�%) "r?-/%) "��!h�,0" ;C� "%)�A*bK&F %)(#�'�,uG-/7>=G01�g=:-/%�%)�,��!L2�(#�AQ�!lc

Page 130: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

v (G� � �)8#0"� �&8j26�A*> 1! � � � �b%)�9268G7>7h-/�� � ��%�(#�'7h-/=G=# 1!#� f -/!:*>�?�,!#�,�.-/%)�'%�(#�'%)�@-A 1!# "!#�26�,%YM� ;2�%)(j-/%+-/010d=:-/%�%)�,��!:2g-/�)�' 3*&�,!\%) 1%�F\m 7s-/=#=:�A*�hlW�� a W _ ] �����+-b268#K:2��,%g�/� � � =:-A%)%��,�)!:2Yc

�+2�-/!L�Pu#-A7>=#01�g�/�B%)(G� 3*&�,!\%) "%6F97h-A=#=# 1!G��h

� � ����� ����� � � � ��� �������� � ����� ��� � � � � ��� � ��� ���� � � ��� � � � ��� � ��� � � �

v (G�H ;*&�P!&%� 1%�F$7h-A=#=# "!#�D-/=#=#0" 1�A2'W�� a W _ ]d �l%�(#� �:�.26%�����8#�R 1!#=#8G%@2�-A�)�H 3*&�,!\%) 3C,-/0xc v (G�,!�h%)(#�'0;-?26%�%�(#�)�,�'K# "%@2�-A�)�'%)�9K:� �j 1=#=:�A*h��!h%)(#�'�?8#%)=#8G%,c �j�?�i�Pu#-A7>=#01�gh

� ��� � � ��� � � � ��� � ��� ������ ����� ��� � � ��� ��� ��� � ���� ������� ��� � ��� ��� � ��� �

�g!#��%�(#�,�)h�7>�?�)�9�) 1�?������8:2^h�Q�-,F %�� *&�A2)CY�) 1K:�h%)(G�L-AK:�/rJ�h7h-A=#=# "!#�L 32$ 1! %)(#�h7h-A%)(#m�,7h-/%� ;C,-A010"F&m�K:-�2��A*�� 2�=t�oC� �dCP-/%) "��!n03-/!#�?8:-/�?� f �J=G 1rJ�,FUh ����� �JM'8:26 "!#�hKt�J�?01�A-A! r?-/0"8#�A2�c ex����h-A�)�b%)(G�kr?-/0"8#�A2i�?![%�(#�b 1!G=#8#%'8#!# "%@2%h � �9%)(#�9r?-/0"8#�A2i�?![%�(#�k�?8#%)=G8#%'8#!# 1%.2%hl-A!:* X[ ;2%)(#�'8#!# "%� 1!:*\�,uk�.-/!#�? 1!#�b���)�?7 � �Ch ���Xh#%)(#�,!h%�(#� � � � �b7h-/=#=G 1!#� C,-/!qKt�D2�=t�oC� �:�o*s%�(&8j2��

�9X�� ����� �� � � � ����

�9X��� ��� �� f � �=� � � � ���/� � � M�� f � �8��� ���JM��� f � � � � � � ����� � � M�� f � �8� ���\M

v (G� %��@-A 1!# "!#�n2��,%)h�C��?!:26 326%� 1!#�n�A�+-/010R=:�J2)2� 1K#0"�qC���79K# 1!j-/%) "��!:2H�A�H "!#=#8#% -/!:* ��8G%)=#8#%r�-A018#�o24%)(:-A% �:%<%�(#��7h-A=#=# 1!G�H*&�o2)C��� 1K:�A*$-AK:�/rJ�gh�(:-�2 � � � � ���,��8#03-/� �/=:-A%)%��,�)!:2 f fc �Jc'hA�)�P��8#03-/�Kt�oC,-/8:2��'%)(#�,F C,-A!LK:�DC������)�AC�%�01Fb7h-A=#=:�A*kr\ ;-$%�(#�' ;*&�,!\%) "%�Fb7h-/=#=G 1!#�\M�-/!j*�� � f -$=#�) "���� M� �,uGC��,=#%� 1�?! �J=:-/%�%)�,��!:2��,c

��� ()-)-%-�C�:�<% ���:�C"����0�:� ��/H2J#K�K� �L���12� (0�:)-)�� "+��( �)-#"8� ���+(, �C����:A! #"C12�.�<%'���%$ .C�:�<� ��<�&=%-� �<��%-��<� �!%'��%'���D&<�� �0� �/�!%?"=� ���� �2�:%-�%-��$.� �12�&<&#4�&���%'&�'"G�<��C"+9" .C�!� �<�� � &<���H)( *+*$.C�:�<� ��<�& L � �!& �:)-& �=(&<#"�<��� �2�:%-�/,,� � �.)-%?1��!� %-���=���7����� I � �(� A ����12)?�:� %-�)�.-�� A �������)/�$� � � � ��$10�2�043 � � ��&<, �:)-)-��3� �2�:%-�%-���&<���%'��<�*.� �& ��+��"+%-& 12(�& & %-���&#4

Page 131: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ��� ����������� � �������������������������� ������������������������������������

�g�A26=# "%)��%�(#���)�,03-/%� 1rJ�,0"FH0;-A�)����!\8#79K:�,�4�A�l(# 3*#*&�,!b8G!# 1%.2 f Q� "%)(9�)�A2�=t�oC�%<%)�+%)(#�g!&8G7kK:�,��/�: "!#=#8#%B-/!:*'��8#%�=#8#%<8G!# 1%.2 MRhA%)(G ;2l%@-�2�S' ;25268#��=#�) 326 1!G��01F *& ��sC�8#0"% �����5%)(# 32 !#�P%6QR����SH%)�g01�A-A�)!8:26 "!#�926%.-/!:*#-A�@*hK:-�C@S&=G�)��=j-/�J-A%) "��!lc v (# ;2R*& ��sC�8#0"%�Fb7h-,FbKt�+%)(#�'�)�o-�26�?!hQ�(&F ��8#010" 1!:-A�) 3--/!:* ��(:-/%��,� f ����� �yM C (#� 26�q%)(#�q26�oC���!:*\m �?�@*&�,� � �JX � Z�� ` ]6W�� �)` �JV W X&] ^ 7>�,%�(#�\* f ���AC@SJ�,�� � ����8#!�h ��� ��� �����?(:-/!:2�26�?!�h �i�AQ�0;-/h � g�J�\*&7h-A!�h �������AMH-?2O%�(#�$%��@-A 1!# "!#�>-A01�?���) "%)(#7 cv (# ;2H-A01�?���) "%)(#7 Q�-?2 -A0;2�� 8j26�A*L "!n%)(#�9C�8G�)�)�P!&%g�)�,=G01 ;CP-/%) "��! �:�,rJ�,! 26�?h �?!#01F -/K:��8G% � ���

�/�B01�A-A�)!# "!#�b%)�� ;-/032�C���!\rJ�,�����A* c��8G0101 "!:-/�� ;-D-/!:*���(:-/%��,� f ����� �yMO*&�A26 "��!#�o*s%�(# ;2�!G�,%�Q�����S �s-/!:*h%)(# 32�!#�ArJ�,0 �,uGC��,=G%) 1�?!

01�A-A�)!# "!#� %@-?26S � =G�) 17s-/�) "01F %�� 268G=#=#01F %)�.-/ 1!G�A* !#�,%�Q��?�)SG2 ����� %)(#�, "�>01�o26 1�?!# 1!G� �,u\=t�P�) 1m7>�,!\%@2�c �g!:C�� 268:CPC��A2)2f��8#010"Fh%)�@-A 1!#�o*�ht%�(#�A2��b!#�,%�Q��?�)SG2OQR�,�)� 268#K����ACY%)�A*h%)�hr?-/�) "��8:2g%6F\=:�A2�/�I26FG26%��,7h-/%� ;C40"�A26 "��!# "!#�g%)�AC@(#!# y8#�o2 f 268jC (9-?24�)�,7 �/r\ 1!G��Q��, "��(\%@2%hA���B(# ;*#*\�,!$8#!G 1%@2 ��%)(G�A26�%)�AC@(#!# y8#�o2OQ� "0105Kt�9*\ ;2)CY8:2)2��A*L 1!n7>�?�)� *&�,%@-A 10< "! 26�ACY%) 1�?! \c � Mg%��L*\�,%)�,��7> 1!G�H �R�)�P��8#03-/�-/!:*h�,u#CY�,=#%) "��!>=j-/%)%��,�)!j2�C���8#03* K:�D*& ;2�=:-/�.-/%��,01Fh- �d�AC�%)�o*sK\Fh2�8:C (q*#-A7h-/�?�Jc

�+2�*& 32)C�8:2�26�A*9=#�)�,r\ 1�?8:260"FUh ��8#010" 1!:-A�) 3-H-/!:* ��(:-A%)�,� � 2 f ����� �JM �:!j*& 1!#�D�/�B-b*&�?8#K#0"�'*& ;2�m26�\C� 3-/%) "��!D ;2lC��?!:26 3*&�,�)�o* 2�%)����!#�H�Pr& 3*&�,!:C��l�����5%)(G� �Pu& 326%)�P!:C��<�A�d-/!D 1!\%)�,��!:-/0 *&8:-/0J����8#%��Jc<ef!%)(# 32 2� 1798#0;-A%) "��!9el�,u#-A7> 1!G��%)(#�g(# ;*G*&�,!98#!# 1%R2�=:-�C��g7>�?�)�g*& "�)�AC�%�01FUh?%)�D26�,�g �I%)(#�P�)�g ;2�-/!\F-�*#*& "%) "��!:-A0<�,r\ ;*&�,!jC��'�/�g- *&8:-/0�����8#%��Uh K#8#%+8:26 "!#�h%)(#���E*&F\!:-/7 ;C �#!#�?%) "��!n�/�N�,uGC��,=#%� 1��!j2*&�A2)CY�) 1K:�A* -/K:�ArJ�Jc v (G� �j�@26%D ;2�268#�> "! 8:2� 1!#� *&F\!:-A7> ;C$�,uGC��,=G%) 1�?!:2H ;2D*&�,%)�P�)7> "!# 1!#� %)(#�C��) "%)�,�� ;-$K\F Q�(G ;C@( =j-/%)%��,�)!j2iQ� 10"0lKt�9CY0;-�2�26�A*q-�2i�Pu#C��P=#%) "��!:2��?�H�)�,�?8#0;-A�@2i "!n- _G`�� ]xV a Z �E`��26 1798#03-/%) "��!lc v (# 32O 32)2�8#�' ;2�*& 32)C�8:2�26�A*>!#�Pu&%Pc

��������� � �'��� � ��� � �H� � �O�� �

v (#� �:�.26%5=#�@-?C�%) 3C,-/0\ ;2�268#�R%)(:-A%<-A�) 326�A2l 1!D%)(# 32 ���,=#01 3C,-/%� 1�?! �A� � � � �� ;2l%)(:-A%<�/�d*\�,%)�,��7> 1!G 1!#�Q�(# ;C@('=:-/%�%)�,��!:2 Q� "010JK:��CY0;-�2�26�A*'-?2<*&F\!:-/7> 3C4�,uGC��,=#%� 1�?!:2 1!'�A-?C ('%)�� ;-A0fc��g!:CY��2��,%)%�01�A*,h,%)(#�C��) "%) ;CP-/0 J8#�A2�%) "��!L%�(:-/% C,-/!q%)(#�,!qK:�b=t� 26�A*L 32OQ�(G�,%)(#�P�i%�(#�b2��,%i�A�R*&F\!:-/7 ;CH�,uGC��,=#%� 1��!j2%)(\8:2i ;*\�,!&%� �:�o*s7s-/%@C@(#�A2�%�(#�b2��,%H�A� � �>-k=#�� 1�?�) 5�,u#CY�,=#%) "��!:2gC@(#�J2��,!nK&F ��8#0"01 "!:-/�� ;-b-/!j*��(:-/%��,� f ����� �JM@c

�+2O7>�P!&%� 1��!G�A*>-/K:�ArJ�Uh:%)(#�' 3*&�,!\%) �tC,-/%� 1��!h�A��*\F&!:-A7> ;Cg�,u#CY�,=#%) "��!:2�����J8# 1���A2�7h-/S\ 1!G�26��7 �n=#�@-A��7h-A%) ;Cn*\�AC� ;2� 1�?!:2�c �iF&!j-/7> 3CL�,u#CY�,=#%) "��!:29(:-,rJ�nKt�P�,!�*&� �j!#�A* %)� K:� %)(#� 26�=:-/%�%)�,��!:2$%)(:-A%kQR�,�)� 7h-/=#=:�A* 1!:C��?�)���AC�%)0"FnK&F %)(G� !G�,%�Q�����S -A%k%� 17>�h]�c v (#�h=#�.-�C�%� ;C,-A0

Page 132: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � ���

=#�)�?K#01�,7 1! -L�� 1rJ�P! 26 "7k8#03-/%� 1��!n 32$%)�n�?=t�P�@-/%� 1�?!:-/0" � �>%�(#�>%��,�)7 � "!:C������)�ACY%)01F��'hI-/!:* %)�C (#�J� 26� -b268# "%@-/KG01�'%) "7>�$]5-A%�Q�(# ;C@(h=:-/%�%)�,��!:2�Q� 10"0lKt�'03-/K:�,010"�A* c

�#�?�i%�(#�$������7>�,�)hGe��)�,%.-/ "!L%)(G�$=:-A%)%)�P�)! C��?�)�)�oC�%)!#�o2)2gC��) "%)�,�� 1��!h8:2��A* %�(#�)�?8#��(G��8#%'%)(G ;2%)(#�A2� ;2 �b-L=:-/%�%)�,��! ;2'C��?!:26 3*&�,���A*[%)�qK:�hC������)�ACY%)01Fn7s-/=#=:�A*nK&Fn%�(#�>!#�P%6QR����Sn ��h ���?�b-A010��8#%�=#8#%�8G!# 1%.2%hJ%)(#�+*& 32)C����,=:-/!jC�FbK:�,%�Q��,�,!b%�(#�g��8#%�=#8#%�-?C�%) "r?-/%) "��!h-A!:*b%)(#�H%.-/�����,%���8G%)=#8#%*&�J�A2H!#��%'�,uGC��,�o* �\c � � %�(:-/%' 32%h f �� 1rJ�P!L%)(j-/%'%)(#�9-?C�%) "r?-/%) "��!n�.-/!#�?� ���?�H��8#%�=#8#%.2 32 � �/h � ��MQ�(#�,!q-/0"0l��8#%�=#8#%@2g-/���' 1!h%)(#� � 2)-/7 �H(:-/0E� �#�/��%�(#�D-�C�%� 1r?-/%� 1��!h�.-/!#�?�b-�2�%)(G�, 1�R%@-/�����,%.2�c

v (G� 03-/%�%)�,�b 32)268G� 32$7>�����hC��?!&%��,!&%� 1�?8:2�c � �AC,-A010�%�(#�qC,-�2��h�/�'%�(#� � 8#0"�>�/� � �n%@-�2�Sf � 8#7>�,0"(:-/��% � � C���0"�,0103-/!:*,h������ yM �&%)(G�,�)�Uh -/010\�)�P��8#03-/�<=:-A%)%��,�)!:25Q��,����01�o-/�)!G�A* ���,0;-A%) 1rJ�P01Fy8# 3C S\01F�hK:�AC,-A8:26�b%�(#�$!G�,%�Q�����Sq26�J��! � "!:*&8:CY�A* �#%)(G�$�)8G01�$8G!:*&�,��01F\ 1!#�9%)(#�D%)�.-/ 1!G 1!#�h2��,%-/!:*b 17>=G01�,79�,!J%)�o*i 1%��DQ�(#�P�)�A-?2T%�(#���,uGC��,=#%� 1�?!$=:-A%)%)�P�)!9Q�-�2501�A-A�)!#�A*b2�01�AQ�01F -o��%��,�)QN-/�@*G2%h-�2 %�(#�b�)8G01�9Q�-�2'-A=#=:-/���,!\%)01F -?* ��8:2�%)�A*[%��h 1!:C��?�)=:���.-/%��> 1% f � 8G7>�,01(j-/�)% � � C���01�P010;-A!:*�h����� /h:�� "rJ�'-k2�%)�,=Gm K\F&mx26%��,=q-�C,CY��8#!\%i�A�<(G�/Q�%)(# 32��\C,C�8#�.2%h# 1!h%��,�)7h2��/�B%)(#�'QR�, 1�?(&%.2 M@c

ef!D%)(# 324C,-?26�UhA��!G��C��?8#0;*' 1!&���?�)7h-A0101F+C�03-�2)2� ��FH=j-/%)%��,�)!j2 �?!b%)(#�RK:-�2� ;2l�/�:%�(#� ^ W � Z#WYX a W5�/�01�A-A�)!# "!#� �5�)�,�?8#0;-A��=:-/%�%)�,��!:2�-/���H%)(#� 26�'01�o-/�)!G�A* �:�.26%)hG-/!:* � y8# 3C S\01F�� �A�,uGC��,=#%� 1�?!k=:-A%)%��,�)!:2-/�)�'%�(#�J2�� 0"�A-/��!#�A*k03-�2�%)h:-/!j* � 260"�/Q�0"F �"c � �,��8G0;-/��=j-/%)%��,�)!j2�-/�)�'0"�A-/��!#�A*kK\F>%)(G�H 1!:*\8:C�%) "��!�/�T- �?�,!#�,�.-/0l7h-A=#=# 1!G��h&Q�(G 101�+�,u#CY�,=#%) "��!:2�-A�)�' 1!jC�����=t�?�@-A%)�A*h 1!:*& "r& 3*&8:-A0101F c

� 26 17 10;-A�D26��J8#�,!:CY�>�/�+01�A-A�)!# "!#�nQ�-?2b-/0326� �,r& 3*&�,!\%' 1! %)(#�s26 17 =#01�9�,uGC��,=#%� 1��! %@-�2�S*&�A2)CY�) 1K:�A* "! 26�oC�%) "��! \c �\c���c �i0"0�=:-/%�%)�,��!:2b�,u#CY�,=#% _ � QR�,�)�h01�o-/�)!G�A* "! %)(G� �j�@26% � ����,=:�\C (:2^h:-/!:*h%)(#�H���?0101�AQ� "!#� � � � �,=:�\C@(:2�Q��P�)�D*&�,rJ�?%)�A*k%��k0"�A-/��!# 1!G� ��8:26%�%�(#�'=:-/%�%)�,��! _ �f 26�P� �5 1��8G�)��\c �yM.c

ef! -L0;-A�)�?� !\8#79K:�,�$�A�'C��?!#!#�ACY%) 1�?!# ;2�%$0"�A-/��!# 1!#�n%��) 3-/0;2$%�(:-/% eH(:-,rJ�>��Kj26�,��rJ�A*�h��/rJ�P�- Q� 3*&�$�.-/!#�?�b�/��%.-�26SG2H-A!:*L!#�,%�Q��?�)SG2%hd-k2� 17> "0;-A��26� y8#�P!:C��'�/�R01�o-/�)!G 1!#�9(:-�2g�/��%)�P!LK:�,�,!�,r& 3*&�,!\% f %)(# 32 �:!:*& "!#�i 32l*&�A2�C��) "Kt�o* "!'7>������*&�,%.-/ 10? 1! �i=#=:�,!j*& 1u��iM.cAef% ;2l79F���K:2��,�)r?-/%� 1�?!%)(:-A%b 1! C��?!#!#�ACY%) 1�?!# ;2�%$0"�A-/��!# 1!#� � ^ ]�=:-A%)%)�P�)!:2b-A�)�h%�F&=# 3C,-/0"01Fq01�A-A�)!#�A* 1! -L���,0;-A%) 1rJ�P01F26(#�?�)%)h#=G�)�\*&8:CY%) 1rJ�gh& 1!G 1%) 3-/0d%)�@-A 1!# "!#�b=:�,�) "�\*�h#Q�(# "01�H%�(#�H�)�P7h-/ "!# 1!#�?hJ�/��%)�P! J8# "%)�H0"�,!#��%�(&Fgh01�A-A�)!# "!#�i%� 17>�� 3242�=t�P!&%<%��)F\ 1!#�g%)�+ 1!:C��?�)=:���.-/%��H-H2�7h-/0"0J!&8G7kK:�,�l�A� ���AC,-A0;C� "%)�@-A!&%l=j-/%)%��,�)!j2�cv (# ;2R26��J8#�,!:CY�i�A�501�A-A�)!# "!#�' ;2%h\(#�AQ��,rJ�P�)h�!#�?%��?K&r\ 1�?8:2 E�5��!#�H�?!#01Fb=G01��%.2 %�(#�H=#���������A2)2� 1�?!�/�g%)(G�>%)�?%@-/0N268#7 �/�+2-y8j-/�)�o*[�,�)�����.2 f -?2$ ;2H�/��%��,! *&�?!#�Uh< "! C��?!#!#�ACY%) 1�?!# ;2�%b2� 1798#0;-A%)���.2%h%)�L=G�)�Ar& 3*&�9r& 3268:-A0T���P�A*&K:-?C Sn�?! %)(#� =#�)�?���)�o2)2 �A�H0"�A-/��!# 1!G�&M@c��+26 1!G�L%)(G ;2H7>�A-?268#���Uhl%)(#�

Page 133: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

!#�,%�Q��?�)S -A=#=:�A-/�.2 %�� 7s-/SJ�n2�%)�A-?*&F =#���������A2)2Yc e �D��!#� 1!j26%)�o-�* =#01�?%@2>%)(#� !\8#7kK:�,�9�/� 1!:C��?�)���AC�%�=:-A%)%)�P�)!:2 f -?2OQN-�2g*&��!#�D 1! �4 1�?8#�)�&c �yMJh#%)(#�D�,u& 326%��,!:C��H�A�R*& 326%) "!:C�%�=:�,�� 1�\*#2� 1!01�A-A�)!# "!#�bK:�AC���7 �A2 7>�?�)�H�Pr& 3*&�,!\%,c

�g�,�)�Uh?e =#����=:�J2��i%��'C�0;-?2)2� ��FH%�(#�J2���=:-/%�%)�,��!:24%)(j-/%�-A�)��01�o-/�)!G�A* "!$%)(G�� 1!G 1%) 3-/0\=:�,�) "�\*$%)�Kt��%�(#���)�P��8#03-/�@2^hJ-/!j* %�(#��0;-A%)�,��m "!:C�����=:���@-A%)�A*,h��)�ACP-/0;CY 1%)�.-/!\%4=j-/%)%��,�)!j24%)�'K:��%)(#�g*\F&!:-A7> ;C�,u#CY�,=#%) "��!:2Yc v (G�[=:�� "!&%h�A�b%)�.-/!:2� 1%� 1��! Q� "010HK:� C���!j26 ;*\�,�)�A* %�� Kt� %)(G�n%) 17 �[]HQ�(G�,�)��)�,�?8#0;-A�@2>-A!:* �Pu#C��P=#%) "��!:29-/��� *& 326%� 1!:C�%9 1! %�(#�, "�>C��?�)���AC�%)!G�A2)2Yc �O��%��,�9%) 17 �[]g01�A-A�)!# "!#�2601�AQg2b*&�AQ�! 26 "��!# �dC,-A!&%�01F �<%)(#�h!#�,%�QR���)S (:-?2$01�A-A�)!#�A* -L�)8#0"�>7h-/=G=# 1!#�q%)(:-A%9C������)�ACY%)01F7h-/=:2�%)(#�'���,��8#03-/�g=:-/%�%)�,��!:2 f K\Fh*&� �:!# 1%� 1�?! MRh\K#8#%+*&�J�A2�!#��%+C������)�ACY%)01Fb7s-/=h�,uGC��,=#%� 1��!j2�c

�5�,�b 10"018:2�%)�@-A%) "��!�h�CY��!:2� ;*&�,�9- =#01�?%k�A�' 1!:CY���)���AC�%b=:-A%)%��,�)!:2b 1! ��!#�q%�F&=# 3C,-/0R01�A-A�)!# "!#�%)�) 3-/0l�A��%)(#� � � ��� %.-�26S f 26�,� �4 "��8#��� &c �yM.c�ef!L%�(#�' 1!# "%) 3-/0 0"�A-/��!# 1!G�k=:�,�� 1�\*s������7 �b%)� ���,=:�\C (:2^hl%)(#�b!#�P%6QR����SL01�o-/�)!j2 %��>7h-A= � ���h�/�R%)(G� � ��>=:-/%�%)�,��!:2'C������)�ACY%)01F c v (#�P�)�A-,��%)�,��h-/017 �J26%R%)(#���,�'%) "7>�A2�-�2�01�?!#�k 32��)��J8# "�)�A*k%��k0"�A-/��!>%)(G� ���,7h-A 1!# "!#� � =:-A%)%��,�)!:2Yc

ef! %)(# 32 "!:26%.-/!:C��gh �?!#�hC��?8#0;* 26�P%$%)(G�k%��@-/!j26 1%� 1�?! %) "7>�>]�%)�qKt� %)(#� ��A%)( �,=:�\C@( �R-/%%)(# 32 =:�� "!&%R%)(#�H!G�,%�Q�����Sb(:-�2�0"�A-/��!#�A*9-$7h-/=G=# 1!#�?hJ��� � �)8#0"� �J%)(:-A%�C��?�)���AC�%)0"Fb7h-/=j2 -A010dK#8#%� �A�5%)(#� ��� $%)�.-/ 1!G 1!#�D=:-/%�%)�,��!:2�c v (#� � b*\F&!:-A7> ;C��Pu#C��P=#%) "��!:2<-A�)�H(G�,!:C��+*&� �:!G�A* Q� "%)(�)�A2�=t�oC�%�%)�b%�(# ;2 f 8#!GS&!#�AQ�! M���8#01�Pm 7h-A=#=# "!#�#c

ef%< 32<%)�)8G��%)(:-A% %�(#�gC@(#�� 3C����A�l%) "7>�H]\ ;2�26%� 10"0#-H7h-A%)%)�P�4�A�l=#�.-/��7s-/%) 3C ��8:*&�?7>�,!\%,c �i�AQ�m�,rJ�,�)hGe QR��8#03* -A�)�?8#�$%�(:-/%+26�,%�%) "!#�k "%g-/%g%)(:-A%i=:�? 1!\%�Q�(#�,�)�D-9C�01�o-/�g*& 326%) "!:C�%� 1��!hK:�,%�Q��P�,!� �A-?26F��4-A!:* � (:-A�@* �5=:-/%�%)�,��!:2 K:�ACY��7>�A2'-A=#=:-/���,!\%)h<Q��?8#0;* Kt�h%�(#�>��=:�,�.-/%� 1��!j-/01 � -/%� 1�?! 1!-kC��?!#!#�ACY%) 1�?!# ;2�%�=:-/�.-�*& "��7 %)(:-A%i7h-A%@C@(#�A2�7>�J2�%gC�01� 26�,0"F>%)(#�' "!&%�8# 1%� 1rJ�g!#��%� 1��!n�A���,uGC��,=#m%) 1�?!:2�c

�g!#�b798:2�%H-?C S\!#�AQ�01�A*\���b(#�AQ��PrJ�,�)h %�(:-/%+%)(# 32 *\F&!:-A7> ;CD*&� �:!G 1%) "��!n�A�gC��?!#!#�AC�%� 1�?!# ;2�%�,u#CY�,=#%) "��!:2RC���8G0;*kK:�D26�,�P!L-?2�8#!:2�-/%) 32���F\ 1!#�Gc v (G�$2��,%��A���,uGC��,=#%� 1�?!:2 %�(:-/%� 32�*&�,%��,�)7 1!#�A*C,-/!>r?-A�)F9���)�o-/%)0"F>*\�,=:�,!:*& "!#�$�?!>%)(#� C������)�AC�%�!#�A2�2�C��� 1%)�P�) 1�?!�h�%�(#�H=:�� "!&%N-/%�Q�(G ;C@(>%)(#�g�,u\m=t�P�) 17 �,!&%��,�d*&�AC� 3*&�A2 %��H2��,%�]BhJ-A!:* %�(#��*&�P%@-/ "0;2l�/�:%�(#��=j-/�)%� ;C�8G0;-/�l0"�A-/��!# 1!G�i%��) ;-A0fc �i�AQ��PrJ�,�)he4C��?!&%��,!:*'%)(:-A% %�(# ;2 � ��8 � � 1!#�A2�2 �, "!b%)(#���?=t�P�@-/%� 1�?!:-/0" � -A%) 1�?!b�/�d�,uGC��,=#%� 1�?!:24 ;258#!:-,rJ�� 3*#-/K#0"� 1! -hC���!G!#�AC�%� 1��!G ;26% C���!\%)�,u\% �g%)(#�P�)�9-/���>2� 17>=G01F>!#�qC�0"�A-/��01Fq*& 32)C��,��!# 1KG01�$��8#01�o2i���'��K����oC�m%) 1rJ�P01Fh*& 326%� 1!:C�%+26%.-/�?�A2i�/�N01�A-A�)!# "!#��hd-�2H%�(#�,�)�DQ��?8#0;*LK:�b 1! -h26F\7kK:��0" ;Ci=j-/�@-?*& 1�?7nc v (#�K:-�2� ;C>=#�)�?K#01�P7 26%��,7h2 ���)�?7 %)(G�L*\ ��sC�8#01%�F �/�+%)��F& "!#�[%��[�?=:�,�@-A%) 1�?!:-/0" � �q-A! ���� 1�? 1!:-A0101F

Page 134: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

Time (Epochs)

Patterns

20 40 60 80 1000

50

100

150

200

250

�4 1�?8#�)� &c � � � =#0"��%g�/�R%)(#�D!&8G7kK:�,���A��=j-/%)%��,�)!j2i7h-/=G=t�o*s "!:C��?�)�)�oC�%)0"F>K&Fq-k���,=#0" ;C,-A%) 1�?!�/�R%)(#� ��8#010" 1!:-A�) 3-k-A!:* ��(:-/%��,� f �������yMg!#�,%�QR���)Sq*&8G�) 1!G�>%)�.-/ 1!G 1!#�Gc v (#�b�?�@*& "!:-/%��b ;2�%)(#�!&8#79K:�,� �A�d 1!:C��?�)���AC�%l=:-A%)%)�P�)!:2 f �.-/!#�? 1!#�i������7 �i%�� � ��yM -/!:*$%�(#��-AK:2)C� 32)2�-i ;2l%)(#�R!&8G7kK:�,��/�l%��@-A 1!# "!#�'�,=:�\C (:2Yc � CY01�A-A� � =#03-/%��A-/8 �? 1!901�A-A�)!# "!#�H�/� � =:-A%)%��,�)!:2�C,-A!kK:�+26�,�P!kK:�,%�Q��P�,!�,=:�\C (:2 ��9-/!j* ���?c

Page 135: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

26F\7kK:��0" ;CHCY��!:C��P=#% f fc �Jc'h\�,u#CY�,=#%) "��!:2^h#Q�(# ;C@(q-/���$8:2�8:-/0"01Fq*&� �:!G�A* Q� "%)(L���A26=:�ACY%i%��>2�F&7>mKt�?01 3C ��8#01�A2@Mg 1! - 2�8#K:2�F&79K:��01 3C$=:-/�.-�*& "��7nc �<-�2�%$���A26�A-A�@C@(#�,�.2i(:-,rJ�>CY 1�@CY8#7krJ�Y!\%)�A*>%)(G ;2=#�)�?K#01�,7 K&F f "7>=#01 3C� E%)0"FtMG=t� 26%�8#0;-A%) 1!G�$%)(G���,u& 326%��,!:C��R�/�5-+26F\7kK:��0" ;C��)8#0"�� 1!b%)(G��!#�,%�Q��?�)S,h%)(:-A% 32i��8#�)%�(#�,�)7 ���)�b=G�)�A2��,!&% -/% ` � � 26%.-/�?�A2 �A�g01�A-A�)!# "!#� � 2���7>�P%) 17 �A2��,rJ�,!nK:�����?�)�9%)(#�!#�,%�Q��?�)S9(:-�2�K:�,�,!L�Pu&=:�J2��A*>%)�9%)(#�'%��@-/ "!# 1!G�926�,% �

��������� � �'��� � � � ��� �

i "rJ�,!n%)(G�9C (#�? ;C��b�A��%� 17>� ] f %)(G� � /%)( �,=:�\C ( MJhl%)(#� y8G�A26%� 1��! -/�� ;2��A2'-�2H%)�hQ�(# 3C ( �)8#0"�7h-/=#=G 1!#�9%)(#�b�? 1rJ�,!q!#�,%�Q��?�)Sq(:-�2H01�o-/�)!G�A*L-A% %�(# ;2g=t�? 1!\%)hl-A!:*nQ�(#�,%)(G�,�H%)(G ;2i��8#01� f -/!j* 1%@2$�Pu#C��P=#%) "��!:2@M'7h-/%.C (#�o2$%)(#� 26�n-?2)2�8#7>�A* K\F ��8#010" 1!:-A�) 3-n-/!:* ��(:-/%��,� f ����� �yM.c e �+%)(#�!#�,%�Q��?�)SL(j-�*[0"�A-/��!#�A*n%)(#�b�,u\=:�AC�%��A* 3*&�,!\%) "%6Fh7h-A=#=# "!#� f "7>=#0" ;C� "%� 1! � � � �JMRh5 1%'Q��?8#0;*(:-,rJ�'C������)�ACY%)01F97h-A=#=:�A*k%)(G� � � � f -$=#�) "���� M��)�P��8#03-/��=:-A%)%)�P�)!:2�-A!:* "!:C������)�ACY%)01F97h-A=#=:�A*%)(#� � � f -O=#�� 1�?�) Md�,uGC��,=#%� 1�?!:2�c5e �#%�(#�� 3*&�,!\%) "%6Fg7h-A=#=# 1!G��Q�-�25!#��%501�A-A�)!#�o*�h/Q�(j-/%�2�%)�@-A%)�,�?FUh��� � �)8G01� �A*& 3* "%<-?*&��=#%B%)�'C��?�)���AC�%)0"FH7h-A= %�(#��7s- ������ 1%�Fi�A�d=:-/%�%)�,��!:2 "!$%�(# ;2l01�A-A�)!# "!#�g%)�) 3-/0 �

�+2i*& 32)C�8j2)26�o*s�o-/�)0" 1�,��h# 1%gC,-A!LK:�$ "!:26%��)8:CY%) 1rJ�+%)�>�,uG-/7 1!#�g%)(#�D�,�)�����.2O%�(:-/%+-/���$7h-?*&���!h%)(#�'�,uGC��,=G%) 1�?!:2 =j-/%)%��,�)!j2%h#-?2O%�(#�H=:-A%)%��,�)!h�/�B�,���)���.2�C,-/!h�? 1rJ�'-A! "!:*& "�)�AC�%R 1!:*\ ;C,-A%) 1�?!�/�B%)(#�'�)8G01�'7h-/=G=# 1!#� 26%��@-/%��,��Fq-?*&��=#%��A* K\F>%�(#�'!#�,%�Q��?�)Sdc

ef! %)(#�sC,-�2��>2�(#�AQ�! 1! �5 1��8G�)� &c �+h4%�(#�k�P�)�)�?�$%�(:-/%D%)(#�9!#�,%�Q��?�)Sn7h-ASJ�A2i�?! %)(#� � *&F&!j-/7> 3CT�Pu#C��P=#%) "��!:2 32 %�(#������0"01�AQ� 1!#�Gc5e�%B*&�J�A2�-A=#=:�A-/�<%��H(:-,rJ��0"�A-/��!#�A*'%)�H 3*&�,!\%) 1%�F\m 7 -/=7>�J2�%H 1!#=G8#%@2^h KG8#%H 1!j26%)�o-�*n�/� �j 1=#=# "!#�>%�(#�k03-�2�%H%)(#���,�bK# "%@2HQ�(#�,! %)(#�"�j�@26%H���?8#�' 1!#=#8G%@2-/�)�'%�(#�D2)-/7 � f -?2i2�=t�oC� �:�o*k 1!h%)(G� � � ���$�)8#0"��MRh\ 1% �: "=:2�%)(G�$2��AC��?!:*h-/!:*h%)(# "�@*&m�0;-?26%�K# "%@2��!#0"FUh:26�,%�%) "!#�k%�(#�'0;-?26%g��8#%�=#8#%gK# 1%g%)� � E�<%�(#��j�@26%�����8G�iK# "%@2g-/�����+h -A!:*L2��,%)%� 1!#�9 1%�%�� � �B%)(#� �:�.26%�����8#�g 1!#=G8#%@2�K# "%@2�-A�)� � f 2��,� v -AK#01�\c �$�������,uG-/7>=G01�A2��/��%�(#�A26�'�,���)�?�@2 M.c v (G ;2 1!:*&8jC��A*k7h-A=#=# "!#�bC,-A8:26�o2 � $=:-A%)%)�P�)!:2�%��bKt�'7h-A=#=:�A*k "!:C������)�ACY%)01F �J-A!:*>Kt�oC,-/8:2��'�/�B%)(#�%6F\=:�A2��/�B�,���)���.2%h#%�(# ;2g26�,%��A�<�Pu#C��P=#%) "��!:2� 32�-b268#K:2��,%g�/�B%)(#� � � � �926�P%��/� � � �,uGC��,=G%) 1�?!:2�c

v (G� � ��8#01� �4 17 =#01�,79�,!J%��A* K\F %�(#�h!#�,%�Q��?�)S 32b26��7 �,Q�(:-/%9K# � -/���)�Uh�K#8#%b���A-�2���!:-AK#01FC�01� 26�9%)�L%�(:-/%bQ�(G ;C@( ��8#0"01 "!:-/�� ;->-A!:* ��(:-/%��,� f �������yM' "!&%��,!:*&�A*n%)(G�k!#�P%6QR����Sn%)�n01�o-/�)!Icv (#�$��8#01�'%)(j-/%g%)(#�D!#�,%�Q��?�)S> "7>=#01�P7>��!\%@2�*&�J�o2%h (#�AQR�,rJ�,�)h\(:-/!j*&01� � b�/����8#010" 1!:-A�) 3-$-/!j*��(:-/%��,� � 2 f ����� �JM+-k=#�) "���� 4�,uGC��,=G%) 1�?!h=:-/%�%)�,��!:2HC��?�)�)�oC�%)0"FUh:26�h%)(G�J26�b=j-/%)%��,�)!j2HC,-/!G!#��%HK:��)�,� -/�@*\�A*h-�2��,u#CY�,=#%) "��!:2� "!h%)(#�DC��?!&%��,u&%R�/��%�(# ;2�0"�A-/��!# 1!G�b%)�) 3-/0xc

Page 136: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

v -AK#01��\c � � �TuG-/7 =#01�A25�/�B 1!:C��?�)���AC�%�7h-/=G=# 1!#� 2<7h-�*&�gK\F>-'�)�,=#0" ;C,-A%) "��!9�/�5%)(G����8#010" 1!:-A�) 3--/!:*���(:-/%��,� f ����� �JM<!#�P%6QR����Sb-/%� "%@2 � /%)( �,=:�\C (9�/�I%)�@-A 1!# "!#�#c �HC�%�8:-/0#�?8#%)=G8#%@2<(:-,rJ��K:�,�,!�)��8G!:*&�A*h� � %)�b%�(#�'!#�A-A�)�A2�%iK# "!:-/��F>r?-/0"8#�Jc

e�!G=#8#% v -/�)�?�,% �HCY%)8:-A0 �g8#%)=G8#%

� ����� ��� ��� � ����� ����� � ��� ��� ��� � �� ����� ����� � � ����� ��� ��� ��� ��� ����� �� ����� � � ��� � ����� � � � � ��� ��� � ��� ���� � � ��� ��� ��� � � ����� � � ��� � ��� ������ � ��� � � � ��� � ��� � ��� � ��� ��� � ������ � ��� ��� � ��� � ��� � ��� � ��� ��� �����

ef!b%�(# ;24%��) 3-/0#%�(#�,�)�RQ�-?2 -H���,0;-A%) 1rJ�P01F'C�0"�A-/�B26�P%<�/�I�,u#CY�,=#%) "��!D=:-/%�%)�,��!:2<%)�HK:�+*& ;2�C��,�)!G�A*���)��7 �4 1�?8#�)��\c � � KG8#%'Q�(:-/%D*&�J�A2H�?!#�>*\� E�R%)(#�,���$ 32 !G��%'-hC�0"�A-/��� =#0;-A%)�A-A8 �:=#�)�A2��,!\%H 1!268:C@(D-i=#01�?%���%�(:-/%5 ;2^h/!G�HC�0"�A-/�B*& "r& 326 1�?!'Kt�P%6QR�,�,!'%)(G� �o-/�)0"F'-/!j*$0;-/%�%)�,�52�%@-A���A24�A�:01�o-/�)!G 1!#� �

�g!n�,u#-A7>=#0"� �A�R%)(# 32HC,-�2��>CP-/!nK:�926�,�P!n 1!n%)(G�b=#01�?%H�/�N=:-/%�%)�,��!:2i01�o-/�)!G�A*L�ArJ�,�i%� 17>�K&Fq%)(#�92�-/7>�D!#�,%�Q��?�)S,h 2�%@-/��%) "!#�>���)��7 -h*& ��d�,���,!&%+26�P% �A�R�@-/!j*&��7 "!# 1%� ;-/05Q��P 1��(\%@2Yc �J�,��4 1�?8#�)��\c &c �i�,���b%)(#�901�A-A�)!# "!#�h=#�)�\CY�A2)2' ;2i�x-/ "�)01F C���!\%) "!&8G��8:2^h Q� "%)( !#�n2��AC�%� 1��!nQ�(G�,�)�01�A-A�)!# "!#�b=#�)�?�����A2)2H2�01�AQg2������'-b01�?!#�k=:�,�� 1�\*�hd-�2g 1!h%)(#�D�,uG-/7>=#0"�H-AK:�/rJ� c�ef!n268jC ( -kC,-?26� 1%b ;2 �x-A 1��01F -/�)KG 1%)�.-/��F Q�(#�,��� �?!#�nC@(#�J� 26�A2b%)(#� ]�r?-A018#�h%)� K:�Jc v (#�,���h ;2$!#� C�01�o-/�b2��,%�/���,uGC��,=G%) 1�?!:2%h\����%�Q�� *& 326%) "!:C�%N26%@-A���A2��/�T01�A-A�)!# "!#�9-�2�Q��'8:2�8:-/0"01F>QR��8#03* CY��!:C��P=#%)8:-A01 � �%)(#�,7 cbef![%�(# ;2'C,-?26�Uhl��!G�hC���8G0;* C (#�J� 26�q]<%)�qKt� -/%D%)(#� ���A%)( �P=t�\C@(�hlK:�AC,-A8:26�>%�(#�,���b ;2-L26(G���)%D=#0;-A%)�A-A8 %)(G�,�)� f �A� ��8:26% � �,=:�\C@(:2 � M@c �i01%��,�)!:-A%) "rJ�,01FUh:��!G�hC���8G0;* 2� 17>=#0"Fq*&�AC� 3*&�%)(:-A% %�(#�b!#�,%�QR���)Sq(:-�*n(:-A=#=:�,!#�A*n8#=:��! ->��8#01�b%�(:-/%'Q�-?2'-/K#0"�b%)�h(:-/!j*&01�9-A010<=:-A%)%��,�)!:2Q� 1%)(G��8#%g-926�,%��A���,uGC��,=#%� 1�?!:2�-A�) ;2� 1!#�Gc

ef%9Q�-?2k!#��%��A* (#�AQ��PrJ�,�)h���! C�0"�J2��,�k�Pu#-A7> 1!:-A%) "��! �A�'%)(G� 26%@-A%)�q�/�D%)(#�n!G�,%�Q�����S -/%���>�,=:�\C (j2%hl%)(:-A%'%)(#�,���bQ��,��� � � 1!jC������)�AC�% f �Pu#C��P=#%) "��! MR=:-/%�%)�,��!:2�c �j8G�)%)(G�,�)7>�?�)�Uh:%)(G�A26�=:-/%�%)�,��!:2 %�8#�)!G�A*H��8#%5%)��K:��=G�)�AC� 326�,0"Fi%�(#�J2��� ;*&�,!\%) �:�A*H-�=#�� 1���� JK&F ��8#010" 1!:-A�) ;-R-/!:* ��(:-/%��,�f ����� �JMR-�2��,uGC��,=#%� 1�?!b=:-/%�%)�,��!:2�c ��8#%�(:-�*9%)(#�H!G�,%�Q�����Sb01�A-A�)!#�o*k%)(#�g�,u\=:�AC�%)�o* f ;*&�,!\%) "%�FtM7h-/=#=G 1!#� � �i!n 1!j26=:�AC�%� 1��! �/�N%)(#�9�,���)���.2HKt�P 1!#�h7h-?*&�b��! %)(#� � �>�,uGC��,=G%) 1�?!:2i=:-A%)%��,�)!:2C���! �j�)7>�A*h%)(:-A%H 1% f -/=G=#�)�Au\ 17h-A%)�,0"FtMB(:-�* c v (#�"�:�@2�% �>K# 1%.2O�A��%�(#�b�,uGC��,=#%� 1��!j2 �#��8G%)=#8#%

Page 137: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

Time (Epochs)

Patterns

10 20 30 400

50

100

150

200

250

�4 1�?8#�)� &c � � =#0"��%g�/�R%)(#�D!&8G7kK:�,���A��=j-/%)%��,�)!j2i7h-/=G=t�o*s "!:C��?�)�)�oC�%)0"F>K&Fq-k���,=#0" ;C,-A%) 1�?!�/�'%�(#� ��8#0"01 "!:-/�� ;-L-A!:* ��(:-A%)�,� f ����� �JM9!#�,%�Q��?�)S *&8G�) 1!G�[%��@-/ "!# 1!G�#c ����!\rJ�,�)�?�,!:C�� Q�-�2�)�A-?C (#�o* -o��%��,� ���n�,=:�\C (j2 �A�H%��@-/ "!# 1!G�#c �i�?%)�h%)(#�q2�7h-/0"0�01�o-/�)!G 1!#�n=#03-/%��A-/8 -/����8#!j*�����,=:�\C (:2Yc

Page 138: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

=:-/%�%)�,��!:2$Q��,���>-A01QN-oFG2$CY���)���AC�%�h4K#8#%b%�(#�>03-�26% �hK# 1%.2 QR�,�)�>%�F\=# ;CP-/010"F ` � � 1! %)(#�>Q�����!#�-�C�%� 1r?-/%� 1��!q(:-/0E��ht�?�H%)�J�?SL�?!n-/!n "!&%��,�)7 �A*& ;-A%)�gr?-/018G�b-/����8#!j* �\c �&c v (:-A%H ;2^ht "% f 7>�����'���01�A2�2 M� ;*\�,!&%� 1%�Fb7h-A=#=:�A*>%)(#�' 1!G=#8#%�=:-A%)%)�P�)!:2�%��k%�(#�'��8#%�=#8#%@2Yc

�+2T%�(# ;2��,uG-/7>=#0"��*&�P7>��!:2�%)�.-/%)�o2%hJ 1%� ;2�-A01Q�-,FG2<=t� 2)2� 1K#0"�H%)(:-A%�%�(#�H-'=#�) "���� *\�A26 "��!:-A%)�A*�)8#0"�A2 f -/!j*[�,uGC��,=#%� 1��!j2 M�7h-,Fq 1!:*&�P�A* K:�9%)(#� 26�h-?C�%)8j-/010"FL����8#!j*[K&Fn%�(#�9!#�,%�Q��?�)Sdc v (#� 17>=:����%@-A!&%l=:�� "!&%B ;2%hA(#�AQ��PrJ�,�)h,%�(:-/%<�?!#��CP-/!#!#�?%�26 "7>=#0"FH-?2)268G7>��%�(# ;2^h�-A!:*$7>�����R*&�,%@-A 10"�A* 1!:2�=t�oC�%) "��!L�A�R%)(#� 26��J8#�,!:CY� �A�R01�A-A�)!# "!#�>-A!:*L%)(G�$%�F&=:�A2��/�R�,���)�?�@2i7h-?*&�' ;2��)��J8# "�)�A*h%)�C���! �j�)7 %�(:-/%g%)(#�'�,u\=:�AC�%��A*>�,u#CY�,=#%) "��!:2�-A�) 326�Jc�ef!L%�(#� �:rJ�'C��?!&rJ�P�)���P!&%�%��) ;-A0;2�%�(:-/%gQ��,����,u#-A7> 1!G�A* "!q*&�,%@-A 10 � h#��!G01Fh��!#�D-A=#=:�A-/���A*L%)�901�A-A�)!h%)(G�$-b=#�� 1���� l�)8#0"�D-/!:*h���,!#�P�@-/%��'%)(#��,u&=:�ACY%)�A*k�Pu#C��P=#%) "��!:2Yc

� *& � �P�)�,!\%' 1!\%)�,��=#�)�,%.-/%� 1��!n=G�)��KG01�,7 -A�) ;2��A2 Q�(G�,![%�(#�,���>-A�)�>798#01%� 1=#0"�'=#0;-A%)�A-A8#un 1!%)(#�'01�o-/�)!G 1!#�9C�8G�)rJ�Uh\-�2� 1! �4 "��8#���&c � c

�g�,�)�h-A�J-A 1!�h� 1%D ;2 J8# "%)�h-A�)K# "%)�@-A�)F Q�(G ;C@( =#0;-A%)�A-A8 ��!#�h=# 3C SG2H%)� *&� �j!#�h%)(#�h2��,%b�/��,u#CY�,=#%) "��!:2Yc �g!#�bCY��8#03* %)(G 1!#Sh�/�T%)(#�D!#�,%�Q��?�)Sq-�2i0"�A-/��!# 1!G�>-k��8#01�H���?�HQ�(# ;C@(h%)(#�P�)�b-A�)�� �'�,uGC��,=#%� 1��!j2 f �?!k%�(#� �j�@26%�=#03-/%��A-/8 MJhJ%)(#�,! *&�,r\ ;2� 1!#� - 7 ���)�NC���7 =#01�,u'��8#01��%�(:-/%R-�*\7> 1%.2��!#0"F � i�,uGC��,=#%� 1�?!:2 f 26�ACY��!:*'=#0;-A%)�A-A8 M ����0"01�AQ��o* �j!:-/0"01F'K&F��i�Pu#C��P=#%) "��!:2 f %)(# "�@* =G0;-/%��A-/8dM@c

ef! 2�8#7>7h-A�)FUh\%)(#�,!�h %)(#� *&�A2� 1��!j-/%) "��!n�A��*\F&!:-A7> ;CH�,uGC��,=G%) 1�?!:2�=#�)�A2��,!\%@2H2���7>�D=#�@-?C�m%) ;CP-/0l=#����K#0"�,7h2� 1!h�?=t�P�@-/%� 1�?!:-/0" � -A%) 1�?!lc �O%g01�o-�26%�h#%)(#�?8#��(�h %)(#�D�,uGC��,=#%� 1��!j2�%)(\8:2iC@(#� 26�,!-/�)�RK:�, 1!#� *&� �:!#�o* Q� 1%�(b�)�A2�=:�AC�%5%)�'-i��8#01�Pm 7h-A=#=# "!#��%)(:-A%< ;25*&�,7 ��!:2�%)�@-AK#01F' "7>=#01�P7k�Y!&%��A*K&Fb%�(#�H�� "rJ�,!9!#�,%�Q��?�)S,h&-A!:*k!#�?%�Q� "%)(>���A26=:�AC�%�%��b-$�)8G01��������Q�(G ;C@(k%�(#�,�)�g ;2<!#�b�Pr& 3*&�,!:C���/�l "%�Kt�P 1!#�'01�o-/�)!G�A* K\Fb%)(G�i!#�P%6QR����S cBe�%BQ�-�2R-/0326�b*\�,7>��!j26%)�.-/%��A*$%)(:-A%�%�(#�i�?!#�g!#�,%�Q��?�)S,h%)�@-A 1!#�o* �?! %�(#�g��!#�'2��,%��A�B*#-/%.- f K#8#%�2�%@-A�)%) "!#� ������7 *& ��d�,���,!\%�2��,%@2��/�5�.-/!:*&�?7 QR�, 1�?(&%.2 MJhC,-/!n�,u\(# "K# 1%+*& ��d�,���,!\%i0"�A-/��!# 1!#�s26��J8#�,!:CY�A2%h f -/=#=j-/�)�P!&%�01F:M�0"�A-/��!# 1!#�s*& ��d�,���,!&%g7h-A=#=# 1!G�J2-/!:*h���,!#�P�@-/%� 1!#�9*\ ��d�,�)�P!&%g2��,%@2��A�<�,uGC��,=G%) 1�?!:2�c

��������� � �B� � � � �@�� � � � � � �H��� � � �i� ��� � �R���@

i "rJ�,!n-h2��,%H�/�N*&F\!:-A7> ;C'�,u#CY�,=#%) "��!q=:-/%�%)�,��!:2%hl%)(G�b%@-�2�SL 32i!#�AQ %�� %��)F -/!:* *&�,%��,�)7> "!#�Q�(#�,%)(G�,�i%�(#�,FUh:-?2H-k�?�)��8G=�hl-/���$8#0"%) "7h-/%��,01F97h-/=G=t�o*s "!n->*\ ��d�,�)�P!&%�7h-A!#!#�,��%��>�)�P��8#03-/�

%��G(C1�12�&<& %���$���7�����<I+& ��%-�<� �2�:�C"G��, %'��%'�<%?�:);���%-���+� & ����<������� �!� #" �!�C"�� �2�:%-�#">(�� �<%-) �$� ��� �!)5�:A!���*���7�����<I & �C��" & (C1�1 �& & A ()-)�� 1 ��������<��#" 4 &����=���7�����<I+&�A �!%')-#" � �>12�������� �� H "+( � �=� ��*A �:%-)-(�< �:A)-%-� & #�!� 1<��&*%-� 12����� (� �!� *���2��"+%-��+� &2L�4

Page 139: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ����������� � �������������������������� ������������������������������������

Time (Epochs)

Patterns

20 40 60 80 100 120 1400

50

100

150

200

250

�4 1�?8#�)� &c � � � =#0"��%g�/�R%)(#�D!&8G7kK:�,���A��=j-/%)%��,�)!j2i7h-/=G=t�o*s "!:C��?�)�)�oC�%)0"F>K&Fq-k���,=#0" ;C,-A%) 1�?!�/�'%�(#� ��8#0"01 "!:-/�� ;-L-A!:* ��(:-A%)�,� � ����� �JM9!#�,%�Q��?�)S *&8G�) 1!G�[%��@-/ "!# 1!G�#c ����!\rJ�,�)�?�,!:C�� Q�-�2�)�A-?C (#�o*n-o��%)�P� � ���h�,=:�\C (:2'�/�N%)�@-A 1!# "!#�#c �i��%��k%�(#�9%)(#���,�926�,=j-/�@-A%)�>=G0;-/%��A-/8Gu -/%���� ���-/!:* � ���b�,=:�\C@(:2 � �/� � ��� � k-A!:* �b=:-/%�%)�,��!:2��)�o26=:�AC�%� 1rJ�,0"FtM.c

Page 140: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

=:-/%�%)�,��!:2OK\F9%)(#�'!#�,%�QR���)S �#%)(j-/%� ;2 �#Q�(#�,%�(#�,��%)(G� !G�,%�Q�����S> 17 =#01�,79�,!J%.2 -9*&8:-A0l�)�?8#%)�D%)�(:-/!:*\01�'�)�,�?8#0;-A�g-/!:*h�,uGC��,=#%� 1��! =:-/%�%)�,��!:2�c

ef! ��(j-/=#%��,� �De *\ ;2)CY8:2)2��A*k-A!:*h*&�,7>�?!:26%��@-A%)�A*br?-/�) "��8:2�%��AC@(#!# *J8#�A2l������ "!&rJ�o26%) "�J-A%) 1!G�%)(#�g�,u\ ;26%��,!:C����A�5-D*&8:-/0d�)�?8#%)�g 1! -$C��?!#!#�ACY%) 1�?!# ;2�%�!#�,%�Q��?�)Sdc � (#�,%�(#�,��%)(G�H2��,%��/�5�,uGC��,=#m%) 1�?!:2H ;2H*\�,%)�,��7> 1!G�A*h-s=G�) 1�?�) � -�2H 1! ��(j-/=#%��,���yMg���'*\F&!:-A7> ;CP-/010"F � -?2'*&��!#�9(#�,����M �d%)(#�K:-�2� ;CH7>�,%�(#�\*#2��)�P7h-/ "!k%�(#�D2)-/7 �Jc

� "%)(q*&F\!:-/7 ;C��,u#CY�,=#%) "��!:2 �&%�(#�' ;2)2�8#�'%)�9K:�$-?*#*&���A2)2��A* 32�26 17 10;-A��%)�9%)(:-A%�=t� 26�A*h 1!��(:-/=#%��,�����'*&�h%�(#�b�,uGC��,=#%� 1��! -/!:*n�)�P��8#03-/�'=:-/%�%)�,��!:2i������7*& 326%) "!:C�%'2�8#K#�?�)��8G=:2 "!n%)(#�!#�,%�Q��?�)S�� 2 "!&%��,�)!j-/0��)�,=G�)�A2��,!&%.-/%� 1��! 26=:-?C���� ef! %)(#�qC,-?26�>�A�'*\F&!:-A7> ;Cb�,uGC��,=#%� 1�?!:2 �5%)(#�y8#�o26%) "��!q ;2�Q�(#�,%)(G�,�i%�(#�J2��b=:-/%�%)�,��!:2iQ�(# 3C (hQR�,�)�D 1!:C��?�)���AC�%)0"F>7h-A=#=:�A*h-/%H%� 17>�b]gQ��,���26�A-A7>01�A2�260"Fi "!:C�����=:���@-A%)�A*$ "!&%��i%�(#��(G ;*#*&�P!$8#!# "%<2�=:-�CY� �/�?�<Q�(#�,%�(#�,�5%)(#�PF$-A�)�R�)�,=#���A26�P!&%��A**& ;2�%) 1!jC�%)0"F ������7 %�(#�'��%)(G�,� �#���,��8#03-/� �&=:-A%)%)�P�)!:2Yc

g "rJ�,! 79F -�2)2��,�)%� 1�?! %�(:-/%b%�(#�q*&F\!:-/7> 3Ck*\� �:!# "%) 1�?! �/�+�,uGC��,=#%� 1�?!:2 32b-L7>�����k!:-A%)m8#�@-A0�-/!:* �)�A-A01 ;2�%) 3C !#�?%) 1�?![�A���,uGC��,=G%) 1�?!:2i "!n%)(#�9C��?!#!#�ACY%) 1�?!# ;2�%'C��?!&%��,u&% �le�Kt�P01 1�PrJ�$%)(G ;226�AC�%� 1�?![Q� "010<���,=:���)%D��! ��!#� �/��%�(#�9Kt�o26%bC@(:-A!:C��A2'26�>�x-A�$�/�+*\�,%)�ACY%) 1!G�h-L*&8j-/0��)�?8#%)�9 1!- !#�,%�QR���)Sdc ���A2� ;*&�o2 %�(#�>8:2��>�/�+-A! 17>=#���ArJ�A*n*&� �:!G 1%) "��! �/�+�,uGC��,=#%� 1��!j2 �5-/!#�?%)(#�P�9-�*&mr�-A!&%.-/�?�i 32T%�(:-/%�%�(#�i!G�,%�Q�����S$8#!j*&�,�RC���!j26 ;*\�,�@-A%) 1�?!k(j-�2�-/0"�)�A-?*&Fb=#�)�\*\8:C��A*9C���!j26 ;*\�,�@-AK#01�V;X �JV � W a ]5�,r\ ;*&�,!jC��'�/�N*&�,rJ�,0"��=# "!#� ->*&8:-A0<�)�?8#%)� � fc � c �:*&�?8#K#01�9*\ ;2)2��\C� ;-A%) "��!:2iQR�,�)�'����8#!j*-o��%)�P��01�A2� 1��!G 1!#�\M@c

v (G� !G�,%�Q�����S>K:�, 1!G�b�,u#-A7> 1!G�A* 32�-$�)�,=G01 ;CP-/%) "��!>�A�<%�(#� � � � �b!#�,%�Q��?�)S � 2�(#�AQ�!L=#���,mr& "��8:2�01FL "! �4 1�?8#�)��\c �\M�%)(:-A%'Q�-�2H%��@-/ "!#�A*L8:2� 1!#�qC��?! ��8#� -/%)�9���.-�*& "�,!\%@2 �'-A!:*[CY��!\rJ�,�)�?�A* 1! ��� �L�,=:�\C@(:2�c �H2$*& 32)C�8j2)26�o* -/K:�ArJ� � -A!:* 26(#�AQ�! 1! �4 1�?8#�)� \c �JM ��%)�@-A 1!# "!#�L(j-�* %�Q��*& ;2�%) 1!jC�%D26%@-A���A2 �k�?!#�>Q�(#�,���h- �?�)�?8#= �/�g=:-A%)%)�P�)!:2$QN-�2 0"�A-/��!#�A* �x-A 1��01F J8# ;C@S&0"Fn-A!:* -/%8#!# ���?�)7 26=:�,�A* �#-/!j*k%)(#�+��%)(G�,� � 26%@-A�)%� 1!#�9-A%��,=:�\C@(�� yM�Q�(#�P�)�+-b267h-A0101�P��268#KdC�03-�2�2��/� � =:-/%�%)�,��!:2H%)�J��Sn798:C@(h01��!G���,�'%)�hK:�901�A-A�)!#�A*dc v (#�o26� � >=:-/%�%)�,��!:2HQ��,���b*&�o26 1�?!:-/%��A*n%)(#��,u#CY�,=#%) "��!:2Yc

v (G� �j�@26%lr\ ;2�8:-/0" � -A%) "��!'%)�AC@(#!# y8G�48:2��A*HQ�-?2l- � V W �)`���a UGV a@` � � � Z ^ ]�W � �+X ` ���o^ V ^ � �� � �

26�,� ��(:-A=#%)�P� �JM9�/�b%�(#�n=:-A%)%)�P�)!:2>�/� -�C�%� 1r?-/%� 1�?!:2k�/� %)(#� � �� %)�@-A 1!# "!#� =:-/%�%)�,��!:2�c �O�%)(#�A2��$%��@-/ "!# 1!G�k=:-A%)%��,�)!:2 � � � �k(:-?*LKt�P�,!nC�03-�2�26 �j�A*L*&F\!:-A7> ;C,-A010"F>-?2i�)�,�?8#0;-A� �d-/!:*�� >-�2

� � &�%-,�.)-�,/��+�<#"�%-�=�<������$ 0 ��3*&<%-,=()?�:� ���3�:A5� �� � �%�����<& %-�)�=�:A%&3��� ���+�<����& ��� #1<I���*�:�C" � ���(�H2J#K+*�K�L A ��� �D"+�& 12�<%'.�� %-��� �!A �<���:..)-%?1��!� %-�����:A 1 �����2(�� �:�<*��� ��"+%-��+� &��<�/12�����#12� %-���%-& � �<� �!%'��%'���C4

Page 141: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

�,u#CY�,=#%) "��!:2Ycv (G��=#8#��=:�J26���A�:%)(G� �� � Q�-?2 %��H*\ ;2)CY�,�)!DQ�(#�,%)(G�,�l�)�,�?8#0;-A�<-A!:*$�,uGC��,=#%� 1�?!:2t=:-A%)%��,�)!:2

(:-�*$K:�,�,!D�� "rJ�,!D*& ;2�%) 1!jC�%4=:� 26 1%� 1�?!:24 1!D%)(#�R(# ;*G*&�,!$8G!# 1%B26=:-?C�� � Q�(G ;C@( QR��8#03*$K:���)� �:�AC�%��A*K&F *& ��d�,���,!&%+=:-/%�%)�,��!:2H�/�g-?C�%) "r?-/%) "��!:2H�?![%�(#�b(# ;*G*&�,!n8#!# "%@2 �4-A!:*n(#�,!:C��bK\Fn2��,=:-A�@-/%� 1�?! 1!\%)�9*& 326%) "!:C�%NC�018:2�%)�,�.2� 1!q-bC�0"8:26%��,�g*& ;-A���.-/7LM.c

v (G� ���A268G01%$�A�'%)(G�hC�018j26%)�P�b-/!j-/01FG26 32 32 "01018j26%)�.-/%��A*[ 1! �4 "��8#��� &c �&c v (#�h�,uGC��,=G%) 1�?!=:-/%�%)�,��!:2<*&�' 1!j*&�,�A*DC�018:2�%)�,�5%)�?���,%�(#�,� �yKG8#%< 1!D%�Q��'2��,=:-/�.-/%��HC�0"8:26%��,�@2 ����!G�g-/%<%�(#��K:��%)%���7�/�B%)(#�D*&�,!j*&���?�@-/7 �:-/!:*h%)(#�'��%�(#�,��!#�o-/�g%)(#�'%)�?=lc

�g!$ 1!j26=:�AC�%� 1��!D�/�d%)(G��C�0"8:26%��,�<*\ ;-/�?�@-A7 Q� 1%�($%�(#��-?C�%)8:-A0# 1!G=#8#%5=:-/%�%)�,��!:24 1!j26%)�o-�*$�/� �-/!:* � 0;-AKt�P0;2 � �)�,rJ�A-A0;2 %�(:-/% �J26 "7> 103-/� %��H%)(G���)�o268#0"%@2 ����8#!:*'Q� 1%�(b%)(#� �� � C,-/���) 1�o* ��8G%4�?!%)(#� �<0;-A8#%<-A!:* � C���0"�,0103-/!:* � ����� �yM5!#�P%6QR����SH 1! ��(:-A=#%)�,� � �A%)(#�NC�018:2�%)�,�� 1!#���A�:=:-A%)%)�P�)!:2l 1!%)(#��(# 3*#*&�,!b8G!# 1%�2�=:-�CY�i 324K:-�2��A*b=#�)�A*\��7> "!:-/!\%)0"F �?!k%�(#�, "�gV;X _ ZJ]#r�-A018#�o2�c v (G ;2�C�018j26%)�P�) 1!G�26%)�.-/%��,��F 7>�A-A!:2H%)(:-A%$=:-A%)%)�P�)!:2'Q� 1%)( 26 "7> 103-/�H "!#=#8#%'r?-/0"8#�A2D-/�)�9���P!#�,�@-A010"Fn�)�,=#���A26�P!&%��A*C�01� 26�'%)�?���,%�(#�,�� 1!h%�(#�'(# ;*#*\�,!h8#!# 1%g2�=:-�CY�Jc

v (G ;2'26%��@-/%��,��Fq�,u\=#0;-A 1!:2iQ�(\FL%�(#�b�,uGC��,=#%� 1�?!n=:-/%�%)�,��!:2H-/���>CY018:2�%)�,���A* %������P%)(#�,� �lK#8#% 1! %6QR�q26�,=:-A�@-A%)� C�018:2�%)�,�.2�c v (#�9�,uGC��,=#%� 1��!j2i 1! %)(#�9%)�?= C�0"8:26%��,�H�/� � � 2 -A010�(:-,rJ�b 1!G=#8#%=:-/%�%)�,��!:2H%)(:-A%'26%.-/�)%'Q� "%)(L����8G��� � 2 � Q�(# 10"�b%)(#� 26�b "!n%)(#�bK:��%�%)�?7 C�018:2�%)�,� -/010B26%.-/��% Q� "%)(����8#� � � 2�c

v (G ;2 �:!j*& 1!#� (# 1�?(#01 "��(\%@2H->CY��!&���?8#!:*& "!#�h=#�)�?K#01�,7 Q� "%)(n%)(G�b-/!j-/01FG26 32H�/�R�,uGC��,=#%� 1��!j2 1!h%)(# 32O%.-�2�S c�ef!%�<0;-A8#%H-A!:* � C���0"�,0103-/!:* � 2 � �������yM�=G�)��!\8#!:CY ;-/%� 1�?!L%@-?26S �#%)(#�D�,uGC��,=#%� 1��!j2Q��,���b���,!#�P�@-/0"01Fh 1!j*& ;2�%) 1!G��8# 326(:-AK#01� �d 1!n%)(G�, 1�H "!#=#8#%+r�-A018#�o2 � ���)�?7 %)(G�b�)�,�?8#0;-A� =j-/%)%��,�)!j2�c�i!G�bC,-A!#!#��%+%)�,0"0 ������7 %)(#� 26=:�,0"01 1!G�k�A��-A! �<!#��0" ;26(nQR���.*LQ�(#�,%)(G�,�i "%i 32O=G�)��!G��8#!:CY�A*L 1!-/!9�,u#CY�,=#%) "��!:-A0&QN-,FJc v (#�P�)�����?�)� ��%�(#�,���� ;2<!#�D-H=#�) "���) G�)�A-?26��!b������%�(#��!#�,%�Q��?�)SD%)�DC�018j26%)�P�268:C@(h�,u#CY�,=#%) "��!>=j-/%)%��,�)!j2O%������P%)(#�,�g 1!h%�(#�'(# ;*#*\�,!h8#!# 1%g2�=:-�CY���# �B 1% � W � W�%��>*\�926� �:%)(G ;2�:!:*& "!#�hQ���8G0;*nKt� -h26%��)��!G�L 1!j*& ;C,-A%) "��!n%)(j-/%' 1%'(:-?2 ���AC��?��!# � �A*L%)(G�k���,��8#03-/��m �,uGC��,=G%) 1�?!*& ;2�%) 1!jC�%) "��!h-A!:* 32�26%)��8:C�%�8#�) "!#�b%)(#�'(# 3*#*&�,!h8#!G 1%g26=j-�C�� -�C,C��?�@*& "!#��0"FJc

ef!>%�(#�'C�8G�)�)�P!&%��)�P=#01 3C,-/%� 1��!9�/�B%)(G��� � � �$%.-�26S �&(G�/QR�,rJ�,� �y7 �J26%R*&F\!:-A7> ;C��,uGC��,=#%� 1��!j2

`�� Wg26 "7> 103-/�g 1!n%�(#�, 1�+ 1!#=#8G%'-/!:* ��8#%�=#8#%'=:-/%�%)�,��!:2H%)�h�A-?C (n�?%)(#�,�D-A!:* (G�,!:C�� `�� W�01 1SJ�P01F

��&���%'&�"+%?�:���2�:, �C�!&����� �0���>� �.�� �"+(C129">���< �:&�%-��%-& �+%-� �<(C�:)-)���(��� #��"� �)- ���/�<� .�� %-�+� #" .C�:�� ��<���<D%-& 1 ���&<% "G�� � �)- 12)-(�<� ���1��!(& 9" ���>� �.( ��� � ���� )?�!..%-��=.C�!� � �� �& �;���%?1<� #��1<�8�C� ���� ) � �C�)5�:A�%'���+� 1<�C�!� ��1 � ��<&#4

Page 142: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � ���

-5 0 5 10 15 20 250

50

100

150

200

250

300

R R R R X X X X R R R R

X X X X R R R R R R R R R R R R R R R R R R R R R R R R R R

R R R R R R R R R R

R R R R R R R R R R R R R R

R R R R R R R R R R R R R R R R R R R R

R R R R R R R R R R R R R R

R R R R R R R R R R

R R R R R R R R R R R R R R R R R

R R R R R R R R R R R R R R R R

R R R R R R R R R R R R R R R

R R R R R R R R R R R R R R R R R R R R

R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R

R R R R R R R R R R R R X X X X R R R R R R R R X R X X X R R R R R R R R R R R

R R

�4 1�?8#�)� &c � �"��018:2�%)�,�+*& 3-/���.-/7�A� � ���h*&F\!:-/7 ;C ���,��8G0;-/� � � � �EMR-/!:* � >�,uGC��,=#%� 1�?! � � � �EM=:-/%�%)�,��!:2�c �i�?%)�g%)(#�+%6QR�D26�,=:-A�@-A%)�'C�0"8:26%��,�@2��/� � =:-A%)%)�P�)!:2�!#�A-/�R%)(#�+%)��=s-/!:*kK:�?%)%)�?7 �/�%)(#�'���.-/=#(Ic

Page 143: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ��� ����������� � �������������������������� ������������������������������������

%)� Kt�qC�0"8:26%��,�)�o*[%)�?���,%�(#�,�9��! %�(:-/%9K:-?26 ;29-/0"��!#� c �i�AQ *&�J�A2b��!#�h%��,010R �+%)(#�,F -/�)�qK:�,m 1!#� C�018:2�%)�,���A*n%)���?�,%)(G�,�$K:�AC,-A8:26�h%�(#�,F -/���q26 17 10;-A�H=:-A%)%)�P�)!:2 �<���$K:�ACP-/8:2�� %�(#�,F -A�)�h-A010�,u#CY�,=#%) "��!:2 �

v (G�,�)�g ;24!G��%��P!#��8#�?(k "!&������7h-/%� 1�?!b 1!9%)(#�gC�0"8:26%��,��*& 3-/�?�@-/7 %)�'���A26�?01rJ��%)(G ;2 y8G�A26%� 1��!Ic�H2H!#��%��A*[ 1! ��(:-/=#%��,����<C�0"8:26%��,�D*& ;-A���.-/7h2H(:-,rJ�9��!#0"F[0" 17> "%)�P* 8:2�����8#01!G�A2)2'Kt�oC,-/8:2��>�/�%)(#�, "�H%)�P!:*&�,!:CYF %��h=#�)�\*&8jC��>CY018#%�%)�,���A* �?�@-/=G(:2 ���?�H�,rJ�,!n7>�o*& 18#79mx26 � �A*>*#-A%@-L2��,%@2 �l-/!j*%)(#�, "�'=:-/8:CY 1%�Fn�/�g "!&%��,�)=#���,%@-AK#01�92�%)��8:C�%)8G�)�Jc �g!#� C,-/! �)�,0" ;-/KG01Fn2�%@-A%)�>%�(:-/%D%)(#�>���,��8G0;-/��m�,u#CY�,=#%) "��!9*& 326%� 1!:C�%� 1�?!k 32T!G��%�%�(#� b` � � � *& 326%) "!:C�%� 1��!9 1!9%)(G�i(# 3*#*&�,!98#!# "%R26=:-?C�� �JK#8#%R��!#�C,-/!#!G��%D2)-,F Q�(#�,%)(G�,�H%)(G�>*& 326%� 1!:C�%� 1�?!n=#0;-,FG2 ->7>�?�)�b7> "!#���+�)��0"�b 1! %)(#� 26%��)8:CY%)8#�� 1!#�h�/�%)(#�'(# 3*#*&�,!h8#!# "%g26=:-?C��Jc

e�%�(#�,����������� %�8#�)!G�A* �?!:C��b-A�J-A 1! %)� �T�� 1!:CY 1=:-A0 ����7>=:��!G�,!&%.2 �g!:-/0"F#2� ;2 � � � � M �: 1!q-A!-/%)%��,7>=#%9%)� *&�,%)�P�)7> "!#�h%)(#�n "7>=:���)%.-/!\%>*\ 17>�,!j26 1�?!:2$�/� r?-/�) 3-/!:CY�n 1! %)(G�L(# 3*#*&�,! 8#!G 1%26=:-?C�� �:-/!j* %)�92��,�' �B%)(#�'���,��8#03-/��m �,uGC��,=G%) 1�?!h*& 326%) "!:C�%� 1��!h 32���!#�'�/�T%)(#�,7 c

���Y�����)� C���!j*&8:C�%� 1!#� -�� � � �dC��,�)%.-/ "!L-?2)2�8#7>=#%� 1��!j2i7k8j26%�K:�bC@(#�AC@SJ�A*k%��>�,!:2�8#�)�D%)(#� 1!\%)�,�?�) 1%�Fq�/�g%)(G�>2���018G%) 1�?! -/!j*[%)(#� r�-A01 3*& 1%�FL�A�+-/!\Fn�)�A2�8#01%� 1!#�q 1!\%)�,��=#�)�P%@-/%� 1�?!:2 � -?2b*& ;2�mC�8:2)2��A*L 1! ��(:-/=G%)�,���>-A!:*L 1! v -/K:-?C (G!# ;C@S � �4 3*&�,0"0 ���� � �JM@c �4 1�.26%)0"F �:%)(#�D(# ;*#*\�,!n8#!# "%@2-/�)�b����J8# 1���A*>%)�>K:� a �JX&]xV;X#Z �JZ ^ -/!:*L(:-,rJ�sX � � b` � ��� �JV ^ ] � V � ZJ]6W��b2�C������A2�c��i 3*#*&�,!q8#!# "%@2 1! %�(# ;2'!#�,%�Q��?�)S -/0"0�(:-,rJ� C���!\%) "!&8G��8:2D-�C�%� 1r?-/%� 1��!j2 K:�,%�Q��,�P! �n-A!:*�� ��-A!:* *& ;2�=#0;-,Fn!#��E26SJ�PQ��A*&!G�A2)2 �/ "!k%�(#�H*\ ;26%��) "K#8#%) "��!9�/�I%)(#�, "�R-�C�%� 1r?-/%� 1��! 2)CY���)�o2T�ArJ�,�T-/010:%��@-/ "!# 1!G� =j-/%)%��,�)!j2 �%)(#�A2��'=#�)�?=t�P�)%) "�A2�Q��P�)�HrJ�,�� �:�o*kQ� 1%�( %�(#� � � � �h2�SJ�,Q�!#�A2�2�%)�A2�% � �i�?�)8� 26 32 � ����� �yM.c

���P 1!#�'-H!#�P8#�@-A0t!G�,%�Q�����S �?%)(#�,���g-/���i�A�5C��?8#�@2��i!#� V ^@^ V;X�� � ` ] ` %��$CY��!\%)�,!:*bQ� 1%�( ��!#�Z&X#V � `�� V ` ]�W��JZJ] � V W �.^ -/7>�?!#�hC,-?26�A2 � -A010<(G ;*#*&�P!n8#!# 1% -�C�%� 1r?-/%� 1��!j2H-/���kK:��8G!:* K:�,%�QR�,�,! �-/!:*��/M �:-/!:* ^ Z�� a V W X&] � ` ] ` �<(:-,r& "!#� ��� kCP-�26�o2� ;2�C��?!:26 3*&�,�)�o* -�� �x-/ "�)m�%)��m����J�\*��l-/7>�?8#!\%�/�T*#-/%.- ������� � � � v -/K:-?C (G!# ;C@S � �5 ;*&�,0"0 ����� � �JM@c

�5 1!:-A0101F �y "%�QN-�2�C��?! �:�)7 �A*k%)(j-/%�%)(G�,�)�HQR�,�)�+!#�%�JZy] � V W �)^D` �JX�� � `�� V ` ��� W ^ � fc �Jc �J(# 3*&m*&�,!n8#!# "%@2@MiK\FL "!:26=:�ACY%) 1�?!n�/�N%)(#��� � � CY���)���,0;-A%) "��! 7h-/%��) 1u �d-/010B(# ;*#*\�,!n8#!# "%@2HQ��,���26 1�?!# �tC,-/!\%)0"F>C��?�)���,0;-A%)�A*>Q� 1%�(h%)(#�'7h- ���?�) "%6Fb�A����%�(#�,��(# 3*#*&�,!h8#!G 1%@2Yc

�+-or\ 1!G�>%)�A2�%)�A* -/0"0< 17 =t�?�)%.-/!\%'-�2�268#7>=G%) 1�?!:2 �5e�=#�)�\CY�,�A*&�A*nQ� 1%�(n%)(#� -/!j-/01FG26 32�c v (#�� � � � �<�) "!:C� "=:-/0 ����7>=:��!G�,!&% �g!:-/0"F#2� ;2��,u\%)�.-�C�%��A*>26�PrJ�,!h26 "��!# �dC,-A!&%��, "���,!\rJ�AC�%����.2T���)�?7%)(#�D*#-A%@- �:%)(G�A26�'-A�)� 268#7>7s-/�) � �A*$ "! v -/KG01�&c �&c

Page 144: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � ���

v -AK#01� &c � � v (#�"�j�@26% 26�,rJ�,! C���7 =t�?!#�,!\%@2��,u\%)�@-?C�%)�o*sK\FL%�(#� � � ��� � � � v � � =#�������.-/7���)��7 -k���,=#0" ;C,-A%) 1�?!L�A��%�(#� ��8G0101 "!:-/�� ;-b-A!:* ��(:-/%��,� � �������yMg!#�,%�QR���)Sdc �#���H�A-?C ( C���7 =t�?m!#�,!\% ��%�(#�i�P 1���P!&r?-/0"8#�� 32<01 ;2�%)�A* �J-�2<Q��P010:-?2T%�(#�g=t�P�@C��,!\%@-A�����A�lr?-/�� ;-/!jC��H-?C,C��?8#!&%��A* ������K\F%)(:-A%�CY��7>=:��!G�,!&% ��-A!:*b%)(#�+C�8#798#0;-A%) "rJ�<=:�,�@C��P!&%.-/�����A�l%�(:-/%R-/!j*k-A010#�A-A�)0" 1�,�BC���7 =t�?!#�,!\%@2Yc

����7>=:�?!#�,!\% �< 1�?�,!&r?-A018#� �4�,�.C��,!\% �A� ������������� �� ��� �� ��������� � ����������������

� "! � �� � ��� ! � � � ! �� � ! � � � � � � ! � � ! � !�� � ��� � �� "! � �#! �� ��! � � � � � � !�� �#!$ � ��! � ����� � � ! � � � ! � ��!$ � � � � ! � � ! �� ��! � �#� � ! � ! �

% �������&���'�#���"���(���)#��* �,+ �����-�� + � � �) � + )#���.����*0/21����3�546) �7�15����89���������"�#� �� �:*;��<�����(7�=����� � � )#� �'> ���(���)#��*?15����8@������������� �� �(*A�#���(�������&�38��.� � �(�3�B�)��-*C�D7����3�:7E���"�3��� + �3�.����F � � !GH8��(*C�I*J�������B�) � + )������"��*5����) ���5��)#�#�.�38����546)#� �� � )�4���8��A�3)#��� � �����3�D���-�� ! GH8��?K-��*C��C1�)L�.���#�.�����(��3)#��*2�����5�38�� � )�*J�;� � + )#�3�����"� � �#��) �"�3�'���L��)#�����38��.�;46)#��� ��� )M*C� ��� )(4N�38���#�(�3�D���-�� ! � )��(*H)#���O)�4P�38��:*C�O�J1H)Q�) � + )������"��*��3� � �:����R�3��� �� �(�3=6��<��� + �3�')#�S7"��*C�����-��3��)�����S�38��A�'�������3�-� � ��� + �3�:*C���"���(�3��)��S)�4P�38��I7��(��� �

GH8�� � �� �������'������� + �����3�����-* � 15���38S����� �� ��� + �����3�����-* � �(FT� ��� �:7���* � � � �(�-7 � 7 > �-� � ���/��<��� + �3�')#�-* � ��F-� ��� �(79��* � � � � 1H����� + � )��3���(7�)#�S��8��LK-��*C�5�J1H)Q�) � + )������"��*U�'�SV;�'� ��� !XW�!

YZ����(�9F-�O*J�����9)��-��[�����(���9��8-�����J1H)& �� *J�3����*\)(4]��<��� + ����)#� + ���3�����3�*H�����^46)�� � �:7 � �3)�38��O��) + � ��46��)�4P�38��I7��D���#��� � �(�-79�38��AF-)#���3) � ������8�� ! GH8��(*J�I �� *J�3����*H�(�����'�_�)��3���(* + )#�7�3)9��8��R�J1H)`*C����*^)(457 > �-� � ��O��<��� + �3��)�� + �����3�����-*L�38���A*J�������O15����8 �#���#� � ��) + � ��46��/����7����� � � F-)��3�3) � �3����8���/ !

GH8���*?����� + 8a�) �� 7 � )��EK-��*C�R� � + ���(*3*J��)#�* � F-�9���"�3��� + �3�.�3�(7_��*R* +�+ )#�3�������_��8��S7 � ��3) �3�b�#��) �"� � �.<��� + �3�')#�-*O�(�-7E����� �� ����*9c�d0e[ � �(��� ��> *J� + �(�������(7E�'�E��8���8���7�7��.� �����* + ���� � F �R15�'�38f)#���S�) � + � ����(�3�')#�2gA�38��h��<��� + ����)��-*A���3�b��)#�Q� ��� ���3) + �:7i��)#�����38��.� �F �R�'�-*C���(�#7f������8����I���j�J1H)B15��7�� ��> *C� + �������3�:7j �� *C�3�.��* ! YZ�E��8��S*J�(����08@�)#�-7 ��3�(7f*C)4k��� � �'��8-��7lF-�����m��*3* �� �(7@�38-�(����<��� + �3��)��-*&1H) �� 7l� +�+ �(���S�'�En *J�_o�pTeh �� *J�3��� � )�� �

Page 145: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

R

X

R

XR

X

R

X

R

X

R

X

R

X

R

X

RR RR

RR R

R

RR

RR

RR RR

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR

RR

RRRR

R

R

R

R

R

R

R

R RR RR

RR RR

R

RR

R

R

R RR

RRRR

RR

RR

RRRR

RR R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR

R

R

R

R

R RR

RR

RR

RR

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR

R

RR

RR

R

R

R

RR

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

R

RR RR

RR

RR

RR RR

RRRR

X

R

X

R

X

R

X

R

X

R

X

RX

R

X

R

V;��� �3� !$W g�� �3�'�-�� + � ��� ) � + )������"��*��L�-� �'> *J��* � � � �?/2)(4 �L�3� + � ��.���3�')#�I)�4N�38���� ���� ���-�(�3�D����-7 � 8-������� � �.W#W# /A*J� �h �� �(�3��)�� ! GH8�� ��� �����(�����'��� + �(�3�3�.�3�-*A����� + � )��3���(7 )��_�38��&K-��*C�� <"=Z�(<��D*0/����7 *C�:�)#�-7 � > =Z�(<��D*0/��) � + )#���.����* � 158����8 ����) ���5��)#�����38��.�^46)�� ��! � )�4\�38���#�(�3�D���-�� ! �5��� �� ��� + �����3�����-*H�(�3�A7��.��)#���(7�F > ��� � ����� ��F-� � � ��8�� � 7 > �-� � �DH��<��� + ����)#�*F > �(� ����� !

Page 146: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � �

� )#��� + �3�(���*C� ��> � ��8-�����38�� �����J1�)#� � 1�) �� 7 �.�-�)"7��A�A�3��� �� �(�3=6��<��� + ����)#�b7��D*C�3�'�-�����)#�&��8-���� ��� )(1H�(7 � � �l�3)OK-�7��L�"���.1 )�����8-����8��D7�7���� ������* + �#��L��8-�����3�.���(� � �(7R* 08h�O)�����=615� >*C� + �(���(�3��)�� / !

YJ*��38��[*C� + �����(�3�')#�S)�4 + �(�3�����3�-*����9��8��[V;��� �3� !$W 7 � �3)&�38��L����)"7������R)�4P�R����� �� ����=��<��� + �3�')#�B7��D*C�3�'�-�����)#� � )��O��*L�'�O�(�3���3��F ���(F � �I�3)B*C) � �A)#�38����L4k�#��3)#� � G2)B*C8��(7 � ����8��5)���38��D*�� �:*C�3�')#� � ��8�� � � � 1 �#*5�3� + � )#���3�(7 *C�'������8��A��� + �5��� �� �(*5�#* � �(FT� � * !

% ���9V]��� �3� !�� � ! GH8�� � ��F-� ��� �(7 + � )��?15�'�38@� ����� � �3������������� + �����3�����-*?�D*? �� ���3�����(7�3)&�38�� + )����"�5)�4P� ��� ���#�'F�� � ��� > � *J) W � )(����� � � +�+ ����� + �����3�����-*H1H�.�3�O��� � )(���(7 ! GH8��O���(* �� �3�'���+ � )��5��*57�� + � �����(7 � F � *C��� ��� �3����(���*H��8��AF-�#*J��O)#�����(�����(�(�3�')#� )(4��38��?8���7�7��.� ����� * + �#�� !

� )���K-� � �����B158-���&1 �#*?46) �-7j���j��8��98��'�����(���8���.� � �� *C�3�.�&���� ��> *C�D*?)(4O��8���*I* + ���� �+ �����3�����-*5�����&���M���'� F-�������&�#�3) + �(7 ����)���7��'���&�3)h�38����� ��� c�d�������o������-e���d���p���������c����e !GH8���*��.�-�)"7��'���j*J�3�����3�.� >l� � � �(* + ���J46�(��b*C���-*J� � F-�(�� *C�_���a�38��D* ���#* � + �(�3�3�.�3�-*�15�'�38*C� � � � �(���'� + ��*9�#�����.�������j*J� � � � �(��) � + ��* � �(�-7 8��.�-��f*C8�) �� 7 F-�j��� + �3�:*C���"�3�(7a � )M*C��3)#�����38����5���S�38��?8���7�7��.� ����� * + �#�� !

YZ� + �(�3�3�D �� ��� � ��8��A)#�����������(�(�3��)�� )(4��38��I* + �#��Q*C��� � * �3)hFT�IF-�#*J�(7 )�� ��8�� � d!��"�.o��"d# ���$P)�4N�38��5��� + � + �����3����� !&% ����� � � +�+ ����� � � ) 7�* � )�42�'� + � + �����3�����-*;15����8&�38�� *�� � �H46) ������'�3��� � F�����*���(�&F-�O7��D*3��.�3���(7&� ��� ��8��3) �#8bV;�'� ��� !�� � ! V�)#���A � �(��������7�� � )#�-*J�3���(�3�')#�&)�4�38��D*\��' �:�� � *J���[V;��� �3� !'�#� �#*�1H� �'� � 158��.�3��n *C���38�� + �(�3�����3�-*�*J�������3�'���R15�'�38 �#�#��� � ����� �� 158��D08h���- �� 7��:*;�38��[7 > �-� � ��H��<��� + ����)��-*0/]�(�-7 � ��� � ��� ��� � � � ��� �3�.� �� ����*�/��(�3� � ��F-� �'� �(7 !

V]��� �3� !���� 7�� � )#�-*J�3�����3�:*\��8-�����38�� 8��D7�7���� ���'�H* + �#��O��* p�o��-)#�������������(7b�#��)���7��'����3) � �3��� �� �(�3=6��<��� + �3�')#�a7��D*C�3�'�-�����)#� � F �h������8����h����)#��7������E��) 46�(�(� ���(*R)�4 �38��S��� + �+ �����3�����-*�g]��� + �(�3�3�D �� ���]�38��HK-��*C�;46) ��F�����* ! � <��� + �3��)�� + �(�3�����3�-*��(�3� �' *C�����3�(7A�3)��#����8����15���38S����� �� ��� + �����3�����-*5�38-�(�O8-� +�+ �.� �3)b*C�������O15����8 ��8��&*�� � � � F�����*�(-�(�-7 �38��A�J1H)b*C�.��*)�42�.<��� + �3�')#� + ���3�����3�*U �� *J�3�����(��*C� + �(���(�3� ���-7�* )�4 �38��58���7�7��.� ������* + �#��546)#����8�� *3� � ��3�(��*C)#� ! GH8��D*^�'������� + �������(�3�')#�_* +�+ )#����*O158-�(�O15��* 46) �-7 �(�(� � �'���5158����fY5�(�3��� � + ���(79�3)���"�3��� + �3���[�38��9F-��8�:�"��) �R)(4[� �������'���(7E�����J1H)#� � ( �'�I� +�+ �(�(�3�(7j�3)B8-����� � �(�������(7f� � �� ��38-�(�R7"� + ���-7��(7 )��_�38��RK��*C�O46) �OF��'��* ! %� �8f���f)#�����(�����(�(�3�')#� *C�3��������� > ��< + � �����*^158 >��<��� + �3�')#� + ���3�����3�*H8-�����L46)#� � �(7h �� *J�3����*�g F-�(�� *C�A��8�� > 8-�����A*C� � � � ������� + � + �(�3�����3�-*���-7 p�o�� F-�(�� *C�I�38�� > ���3�A��<��� + �3��)��-� � !

�[*U��)��3�(7��:��� � ����� � �38������O��*�� + )#�����"�3��� � �)���46) �-7������&���9��8�� � � W# ���#* � 158��D08`�) � =

Page 147: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

00000000

00000011x00000100

00000101x00000111x 00001001x

00001010

00001011x

00001100

00001101x

00001110

00001111x

00000001x

00010001

0001010000010110

00010111

0001101000011011

000111000001111000011111

00100010

00101000

00101001

00101010

00101011

00101101

00101110

00101111

00110111

00111100001111010011111000111111

0100010001000110

01000111 01001011

0100110001001101

0101000101010011

01010100

01010110

0101100101011011

0101110001011110

0110000001100001

0110100001101010

01101011

01101100

01101101

01101110

01101111

0111000001110010

01110011

011101000111011001111000

0111111010000000

10000100

1000010110000111

10001000

1000100110001011

10001100

10001101

10001110

10001111

10010000

10010001 10010010

1001010010010101

10010111

10011001

10011010

10011011

10011100

10011101

10011110

10011111

1010000010100010

10100011

10100100

10100101

1010011010101001

10101010

10101011

10101100

10101101

10101110

10101111

10110000

1011010110110110

10110111

10111000

1011100110111100

10111101

10111110

10111111

11000001

11000010

11000100

1100010111000111

1100100011001010

11001011

11001100

11001101

11001110

11001111

11010000

11010001

11010010

11010011

11010101

11010110

11011000

1101100111011011

11011100

11011101

11011110

11011111

111000001110000111100011

111001001110011011100111

11101000111010011110101011101011

111011001110111011101111

11110000x

11110001

11110010x

11110011

11110100x

11110101

11110110x

11110111

11111000x

11111001

11111010x

1111101111111100x

11111101

11111110x

11111111

V;��� �3� !�� � g �\�����-�� + � � � ) � + )������"��* �L�� ��> *C�D* � � � �A/A)�4I� ��� + � �D�������)��j)�4A��8�� � �� =� ������3�D�S���-7 � 8-�(�3��� � ��W�W# /&*J� �h �� �(�3��)�� � 15����8 � �(FT� ��� �:7 + �(�3�����3�-* ! GH8��D* + � )#� *C�(*A�38��*3� � �R�J1H)S�) � + )#��������*L��*O���fV;�'� ��� !$W � F �[��)(1 �38��&��� + �O��� �� �(*O�#*�*C)"��D�����(7 15�'�38�(�#�8 + �(�3�3�.�3�@�(�3�B*C8�)(15� ! � ��� + ���(*C���"���(�3�'���h* F-*J���&)�4 � + �����3�����-*R��*I7���* + � � > �(7f�3)�3�(7 ��A �' �3����� ("��<��� + �3�')#� + ���3�����3�*^8-�����A�(� � < � � +�+ ���-7"�(7 !

Page 148: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� � � � ������������� � � �

00000000

00000001x

00000010

00000011x00000100

00000101x

00000110

00000111x

00001000

00001001x

00001010

00001011x

00001100

00001101x

00001110

00001111x

. . . .

. . .

.

. .

. .

. . . .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

..

..

....

.

.

.

.

.

.

.

. .. ..

.. ..

.

..

.

.

. ..

....

..

..

01100000011000010110001001100011

011001000110010101100110

01100111

01101000

01101001

01101010

01101011

01101100

01101101

01101110

01101111

.

.

.

.

.

.

.

.

.

.

.

..

.

.

.

.

.

.

.

.

.

.

.

.

.

.

..

.

.

.

10010000

10010001 1001001010010011

1001010010010101

1001011010010111

1001100010011001

10011010

10011011

10011100

10011101

10011110

10011111

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

..

.

..

..

.

.

.

..

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.. ..

..

..

.. ..

....

11110000x

11110001

11110010x

11110011

11110100x

11110101

11110110x

11110111

11111000x

11111001

11111010x

1111101111111100x

11111101

11111110x

11111111

V;��� �3� !'�#� g � � �3�'�-�� + � � � ) � + )#�����"��* �L�� ��> *C�D* � � � �?/])�4P�O�3� + � �D�������)#�h)�4 �38�� � ��'� ��=�-�������A���-7 � 8-�(�3��� � �.W#W� /�*J� �h �� �(�3�')#� � 15����89�A* F-*C����)(4 � �(F-� ��� �(7 + �����3�����-*�*C8�)(15� ! GH8���*+ � )�� *J�(*R�38��`*3� � ���J1H)f�) � + )#��������*A�#*R���iV;��� �3� !$W � F �R��)(1 )#� �'> + �(�3�����3�-*&�(�3�*C8�)(15� ��8-��� *J���(�3� 15���38S��8��O46) � F�����* � � ����� � � � �#�#��� � � � � ��� � � )�� � � ��� � � ! % �38���� + �(�3�����3�-*���3�I*J8�)(15�_�#* 7�)���* ! GH8��I7 > �-� � ��L��<��� + �3��)��-*U)(4��38���*H�3����� � 8-�����I��� � < � � +�+ �.�-7��(7 !

Page 149: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� �� ����������� � �������������������������� ������������������������������������

+ � �D������(*5���-� ��> *C�D*^)(4��38��A8��D7�7���� �����[* + ���� ! GH8��R��<��� + �3��)�� + �����3�����-*^� > + ��.� ���'> 46) �7���3�`*C� � � � �(�O��� �_7�� ' �.�3���"�I*C���-*J��F-�(*J��7��:*?F-������� ��<��� + ����)��-*�( ��8�� > 8-�����b*C� � � � �(�O��� + �+ �����3�����-* ! GH8��9�����J1H)�� � 08�)�)�*C�:*R�3) )��3�M����� ���9�38��98���7�7���� �����&* + �#��9F-�#*J�(7j)#�j��8-���F���� + �(�3�����3� � �(�-7 ��8���*H)��3�M����� �(������)#� � �(��7�*H�3)b�)����-��D7����"��� � �' *C�����3�'���R)(4��38��A��<��� + �3��)��+ �����3�����-*^�'�9�38��?8���7�7��.� ����� * + �#�� !

YZ� * ��9� ��� > � �38���� � ��)��.���D7����-��A1 �#*^46) �-7 ��8-���[�3��� �� �(�O�(�-7 ��<��� + ����)#� + �(�3�����3�-*���3�h�3� + �3�(*J���"�3�(7B7�� 'N��������� ��> ���_�38���8��D7�7���� �����I* + �#��h)�4 �38�� � � W� �����J1�)#� � � ��<��� + ���p � ����e�p �kc��������#* + �(�3�O)(4����_)��3���(�����:���3�')#�_F-��*C�(7S)#�_�'� + � ��� �� �(* ! GH8��� �(*C����)�� �-�(� =��� �'��> ������*C�:*H�#*5�3)I158�����8���� �&7��D*C�3�'�-�����)#�b1H) �� 7�8-�����OF-���.��46) �7 � 4]��8��A*J���5)�4P� + ����)��3���<��� + �3�')#�-*����-7 ����� �� ����*H15��* *J�(7 �'�-*C���(�#7 ! YZ�S�38��D*L.�#*C� � �38��I���*C1H�.�L�D*H�������(�3�'��� ! �O*V;��� �3� !���� *C8�)�1 * � �38�� � + �3�')#������<��� + �3��)��-* � � ! � ! � ��8�)�*J� + �����3�����-*;��8-����*J���(�3� 15�'�38 � ��� ��� �)#� � ���#��� � /\�����R*J� + �(�������(79���h8���7�7���� �����5* + �#�� � ���-7h�38��O�J1�) � )�)�*J�I �� *J�3����* �38�� > 46)#� ����3� � ��F-����� ���'> �'��������* + �.��*C�:7�15����8 ����� �� ��� + �(�3�3�.�3�-* !

� � ��� ����� � ��

�H��46)#���h7�����15����� �)#�- �' *C�')#�-*546�3) � ��8��h��F-)(���b���-� ��> *C��* � �38��R46) ��� )(15�'��� + �3)(�"��*C) � * �h *J�FT� � ��7�� ! V;����*C� ��> � )�� ��> )#���b�����J1H)�� � 1 �#*A��<�� � �����(7 � )#�f)#���9�����(�����'���S� � ! � � )#�����<������-7��:7 �(�-� �'> *J��*&)�4 �h �� ��� + � �����.�C1�)#� � * � �3���������(7 �7����b7�� 'N���������h�)#�-7��'�3�')#�-* � � ! � ! �15���38a7�� 'N���3���"� � �:���3�������f� � �#)��3�'�38 � *�/ � � >f> �'� � 7 ���l�.<�� � + � �b158����3�B�_7��D*C�����-�����)�� �

� �#7��b���"�3�����-� �'��> FT�.�C1������j��8��S��<��� + ����)#�i���-7@�3��� �� �(� + �����3�����-* ! GH8���*&)#��� �.<�� � + � �7�)��(* � 8�)(1H������� � *J8�)(1 �38���b���l�'�������3�� � 7��D*C�3�'�-�����)#�@F-���J1H�.���@�3��� �� �(�9�(�-7 ��<��� + �3��)��+ �����3�����-*^�D*H��)#�Ip-e � e .c�d��^46)��O�R�����J1H)#� � �3)h� � + � � � ����� ��8�� � �#*C�'�3��� �� �(� � � W� ����* � !

G2)h)#F��������B�RF���)���7���� + �.��* + �(��3����� � 46) � � )#���L���.�C1�)#� � *H1����3�O�����(�����(79)�� ��8��I*3� � ����#* � �2 *J�����S��8��h*3� � �R�������'������� � � ��)#�3�'�38 � ���-7_�3�����'�������B7��(��� � F �I*C���(�3�������946�3) � 7�� 46=46���3���"��*J����*�)�4]���(�-7�) � 1�������8���* � �38�� �3�����'�������I*�08��:7 �� �:*\)(42�J1H)I)�4]��8��(*C� �����J1�)#� � * 1H������#��� + 8��(7 + �������') * ��> ��� *C�:��3�')#� ! � ! � / ! � � ' �.�3���"�O�3)���� � �����(�����'���9�3� � �(*51H�����R���(�)#��7��(7� �� � � � W � W � ���-7 � ��� � + )"08-*R���(* + �(��3����� ��> /O��*R1H�����S7�� ' �.�3���"�R� �� FT�.��*?)(4A7 > �-� � ����<��� + �3�')#�-* � � � � ��� � ��� / ! �L�M����� � � � � ���-� ��> *C�(*L)(45��8��(*C�I�����J1H)�� � *O7��D7 ��)#�O�������(� ����"�3�����-� � *J�3� �� ��� F-��*C�(7l)��m�38��B�3��� �� �(�3=6��<��� + ����)#� 7���*J�3�'�-��3�')#��� ! YZ�"�3�����(*C������� ��> � � ���

����()-);"+�� �!%-)'&��!A �<��& $�:�C�!)/�+&<�& �C� �� �0��� ��,/%-� �<#"$A ��� �� �+%-�)�+4

Page 150: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���

�� ���� ��� � ��� ��� ��� ����������� � �

*C����*H)�4�7 > �-� � ��5��<��� + ����)#�*U46) �-7S1H�����A* F-*C����*^)(4��38��R� + ����)#���2*J���L)(4 � �.<��� + �3�')#�-* ����-7l��8�� � � �� �(* � �38-�(�SYR���"�3�.� + �����3�(7j��8��(*C�B�����J1H)�� � *��3) FT�B� � + � � � ���"�3� ���f���h�3� � � �

� F-��*C�(7�)��9�38��O���3��)#��*U�38�� > 1H����� � � � �����"/21H�����L� > + ��.� ���'> )�� ��> * � ����8��������3�D������)#�*U)#�b�38����7����"�3�'� > = � � +�+ �����A� �� � !

YZ� 1H) �� 7B� +�+ �(�(�O�38-�(� � � o�p���d� &c��ko�d��L�3) � ��'� �'�-�������&���7 � 8-������� � * � ��W#W� /[�#*�* �� + =�3��)�� � ��8��9���.�C1�)#� � 7���7_���-7 ��h�3� � ����F ��> ��8��S� +�+ �3)(<"� � �(�3�&�D7����"�3��� > = � � +�+ �'���S*J�3���(�3��� >46�3) � ��8�� �3���(�����'���I*C��� 46)�� � )�*C� + �(�3�����3�-* ! GH8�� �����J1H)�� � � � *J)&7��D7�*J��� � ��)R8-�����5���3) F � �� �(�(�3���'���R��8��O�)#�3���(�� � � +�+ �����?46)#� + �����3�����-*U��8-��� *J���(�3�3�:7�15����8�46) ����7��.�������� � F�����*�("F ��38��A���� � � �.�3�3)���*��38-�(�H��� � �#7"�5)#�S�38��:*C�[7�� 'N�����(7 46�3) � ���3�D� � �3)I�3�3�D� � � .� *J�����&F-���J1H�.���� �(�-7 � 7 > �� � �DL��<��� + ����)#�* !

YZ�I* ��9� ��� > ��8���� � *C� �� �� ������)��-* ��(�3�����(7L) � )��?K-��� �����(�����(7A��<"� � + � ����*�)(4 � ���� ���-�(�3�D����-7 � 8-�(�3��� � * � �.W#W� /������J1H)�� � 46) �-79��)h7"���3�:��H)��5���-7��'�3�(��U�.���D7����-��546)#�5��8��A��<"��*C�����-��)�4 �S7 � � �3) �3� � �������B�38�) �#8 ���f� � + �3)(���(7 � 7 > �-� � �D�/ 7���K-���'�3�')#�_)�4���<��� + �3��)��-*515�#* *C�(79�'� ��8��I*C�����3�D*C������ � ���-� ��> *C��* !

����� � � ����� � �� � ������ ���������

GH8��RK-�-7��'����*O��� + )#�3���(7 ���_��8�� + �������') *[*C�(�����)��f� +�+ �(�(�?��)S�)��������#7"����O��8��&�3�:* �� ��*L����=+ )��3���(7 F > � ��'� �'�-�������R�(�-7 � 8-�(�3��� � ��W�W# /[��46�3���[�)#�7 ��������b� � �:*C��)��������9*J� 7 > )��_�38��*3� � �O�����J1H)�� � �(�-7 � �(�����������&���#* � !

� ���� �'�-�������h���-7 � 8-�(�3��� � ��W�W# / �; *J�����S��8������[*C�.�O)�4 � � + �3�')#���,/��3��� �� �(��*A���-7_��<��� + =�3��)��-* �"� �(*J��)����(7���<"� � + � ����*;)�4P�38��A��F-)(���O�����J1�)#� � �(�-79�3� + )��3�3�:7 ��� .o � ��c�����o�p �F-���J1H�.����38����'���3��� �� �(�5���7���<��� + ����)#� + �(�3�3�.�3�-* ! Y �h)#���A��#*J�O�38�� > �������&46) �79� ��o�� # ��e ��� .o � ���c�� ��o�p&FT�.�C1������S�38��(*C�A�J1H)h*J����*5)�4 + ���3�����3�*^�'� ��8��R)����A�����J1H)�� ��� �38��&*C���3)����#�(*J�L���(* �� �+ )M*3*J��F � �O���h�38�� � �(*J��)#������� � ����8�)"7�) � )#� > � �(�-7���8�) ��8��5��)RF-�O�'�-7���.���3�'���H)(4��I7 � � �3) �3�4 �-�����)#�� � ����08����3�:�� ��� � % 8-� ��� �D�� � ��W � � / !

� )�1 � �38��.� � ��)&�3�(�)��-�� � � �38��D*U� � + )��3�����"�H�3�:* �� �U15�'�38 �h> �#*�*C�����3�')#�S�38-�(� � ���� ���-�(�3�D����-7 � 8���3�.� � ��W�W# / �Nd3o # c # � � * + �(�� K-�(7&�38�� *C����)�4]�3�.� �� ����*����-79��<��� + �3��)��-* ���-�)#�3���(�� ��> ��38-�(�&�38��B*C�.�&)�4 7 > �� � �D ��<��� + �3��)�� + �(�3�3�.�3�-*&�8-�����#�(*&)#�@������� >E� �(����������� �3����� � � ���7�38-�(�?��) �.���D7����-��O46)��9c�p �Q�'�������3�� � �3��� �� �(�3=6��<��� + �3�')#�f7��D*C�����-�����)�� � 158�����8����A7 > �-� � ��)#� � + �3�')#�3�6/�15��* 46) �-79���S�38��?�����(�����(7 � � W� ���.�C1�)#� � ��<�� � �'���(7h��F-)(��� �

Page 151: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � ����������� � �������������������������� ������������������������������������

� ���� �'�-�������h���-7 � 8���3�.� � * � ��W#W� / �3�:* �� ��*L1����3�I���"�3��� + �3�����(7 ��*O*3� � �'����� � ���7������(��5���"=��7������&�38-�(�&�(�j���"�3�����-� � 7��D*C�����-�����)��f7�)��(*?�.<��D*C�O46)#�I�3��� �� �(�R�(�-7j��<��� + ����)#� + ���3�����3�* !�L)(1l� � *C� � ��8��[7���*�*C)"��D���3�')#���D*C���3�:�#*C)��������R�#)��:* � �) �� 7 ��8��(*C� + �(�3�3�.�3�-* F-�L�'�-7�� + ���7����"� ��>7�� � �(�#�(79F >�� �(*C�')#���'��� � GH8��?�.���D7����-�� 15��* � 8�)(1�������� � *C��� ��� )#� �'> ��p�����d�e � � ("��)h���-7�� + �.��=7����"���)#���3)�FT)����(�3��)��915��*�*C) �#8"�HF > � ��'� ������3�D�L�(�-7 � 8-�(�3��� � ��W#W� / � � ! � ! � F > ��<�� � ����������38��A8��D7�7���� � � > �����3� + �3�(*J������������)#�* � �#*515��*L7")#���I���S�38��D*5���-7S�38�� + �����"��) *L�8-� + �3����/��3)�)#��K� � )��O7��.� > �38��A��<"��*J�3�����O)�4\* 08B�h7���*J�3�����3�')#� !

YZ�9�D* ��)#� + )�*3*J��F � �_�3)j�.<�� � �����S��8�� �-e � � � � � � W# ���.�C1�)#� � �.<�� � + � �(�&)#� 158����8�38��B7�) F � �B7��D*3*J)"����(�3��)��@15�#*R46) �-7 � �3)f*C�.� � 4A�(� > ���7�����(�3�')#�@)�4 � ��� + ���(*C���"���(�3�')#�-� �7���*J�3�����3�')#� F-���J1������_�3�.� �� ����*[���-7_��<��� + ����)#�*L��* + �3�(*J����� ! �L)(1H�����.� � ��� � + )�*�*C��F � �h�3)�3� + � ����(�3� � ���� ���-�(�3�D�?�(�-7 � 8-������� � * � ��W#W� / � �(*J��)��������I��< + �.�3� � ������* )��S�38��O�����J1H)#� � n *C���<�� � �����(7 � ��)f7����3�.� � �'���R� 45�38���*?�����J1H)#� � � ���j158����8E��)f7"���3�:��A�����D7����-��&15�#*O46) �746)#�H��8�� ��<��D*C�����-��5)(4P�R7 � � ��) ��� � � � *J)&7�� � )#�-*J�3�����3�:*U�I7�) F � �A7"��*3*J)"����(�3�')#�9F-���J1H�.����3��� �� �(� ���-7S��<��� + �3�')#� + ���3�����3�* !

Y,4I�f7�) F � � 7���*�*C)"��D������)#�m)(4Q*C� � � � �(� � �(�#���'� 7"� � I46) �-7l�'�@�38��D* ���.�C1�)#� � � ��8�����38��D*QK-�7������ 1H) �� 7 1��(� � �.� ��8�� �'��46������������� �5� ��� � F-���J1H�����a7�) F � �_7��D*3*C)"���������)��-*9���7� )"7 �� ���S�(���8������(�� �3�(* � �(� � �(�#*J� � ��*`4k�(� ��*`46���:7 46)#��15����7 �)#�����:��3�')#���D*C� � )"7"� � *9�(�3��)#�-����3���:7 ! Y,4]��)h7�) F � �A7���*�*C)"��D������)#�S�D*\46) �-7 � ��)h*J�3�3)����h�)��- �� *C��)��-*5��(�9F-�R7"����15� (�38�� ���3���"�9�����J1�)#� �m� � > *J� � + �'> 8-����� 46) �-7 �(� �'�������3�-� � )#�3�M����� �(������)�� �38-�(�S15�#*�� + �(F � �B)�4I� � + � � � ���"�3�'��� ��8�� � �#*J������� �� ��� � � +�+ �'���f15���38�) �S�)#�-*J�3� ��3�'���@�j7 � ��3) �3� !

����� ����� � � ���� � � �� ���� � � ��� ��� � � � � � ��

� � �� ���� ����� ��� ��� ��� � ��

����� ��� � ��� �! ��" $#% �& ��L���3� YU15� �'� F�������� > )(�����3�"����1a�38��A����������� �2� �:*C��)��������h���-7B7���*�*C)"��D���3�')#� � ���38�)"7�) � )#� > � �#*���A��*A� +�+ � �'�(7E�3) �)#�����(�����)#����*C�A���.�C1�)#� � * � F-��46)��3�9� �3�������B�3) ��8�� + �3�(*J���"�R*J� �h �� �(�3�')#� !GH8���*H)(���������'��1m15� �'� ���D79���S�38��I7��D*3 *3*C�')#�S46) ��� )(15�����I�38��I*C� �� �� ������)�� !

Page 152: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� � � ����������� � � � W

GH8��EF-��*C�D ��)�� � )�4Q�38�� � �(*J��)�������� � �.�38�)"7�) � )�� > �'� �)#�����:��3�')#���D*C�9���(*C�(�(���8 �D*9�3)*C� �h �� ���3�Q7�� � ���#� � ���-7f�38��h��'N�(���*L)�4[7�� � �����#/5��8-���I8-�#*OF-�����f)#F-*J���3���:7 ��) )". �A����3�(� � � 8 �� �(� / � ��� ��� � �����J1H)#� � * � � �38-�(�A��* � �38��h��.������� � ��������) *A* > *J�3� � ! G )S��8���*L�.�-7 ����3��� KN���� � ��� ��� � �����J1�)#� � *A����� �����(�����(7_)#� � � +�+ �'���S���#* � * � * �8@��*?�38�� � � W# ���#* � / ����� � �R����3������� � F-��*C� � �����#/ � ����� � )(4 + �.�C46)#� � �����L�D*U���(�#�8��(7 ! �����3�') *U46)�� � * )(4P7�� � �(�#����3�S��8����@��� �������(7E)#�a�38��S���.�C1�)#� � � * 08a��* ��� � )(���'���S1H���'�#8"��*R)�� + �.�3� �3F��'���E��8����'��#� �� �:* ! GH8�� + �.�C46)#� � �����9)�4[�38�� �����J1H)#� � ��*R���(�#*�*C�(*�*C�(7 �-7��.�&�38��(*J�B�)#�-7"���3�')#�-*&)�47�� � �(�#� � � > + ���� ���'> ��)l*J��� � 4IFT�.8-�����') �h)#F-*J���3���:7l���l8 �� �(�-*��D* �� � � e�� �'� *C) � �15� > F > �38��&�����J1H)#� � ! GH1�) ���(����"�A*J� 7��'�(*O�38-�(�A8-����� *C�(7f* 08 � � ���38�)"7�) � )#� > �(�3�� �����3����*C)#�B��� � � ! � ��W � W / �(�-7��_�(���8 � �(� � �.W#W � / !

� �R� � + )��3�����"� � �:*C�3�')#�A15����8&* 08Q*C� 7����:* �D* 8�)(1@�) � + �(���(F � ���38��H7�� � �(�#�(7A��� ��� ������J1H)�� � *?�(�3�h�3)S�3�:� � � 8 �� �(� / � �:*C��)��������S��#*J�(* !� ����8EF������'��=Z7�� � �(�#�(7 + ���������"��* � )#���������� ��> � ��)(1 *2�38�����<��#��2�-��� �3��)#�]���"�3�����-� ��� )" *2)�4�38���7�� � ����� � � � ��8�) ��8&�38�����<"�3�.�3�-� ��� *J�5��* � ��)�15� � � ! � ! � *C���3) � � � � �-*C8�)#��1H) �-7T/ ! GH8���* �-����������'��� >O� � � �(*2* + �:�� KN���#*J�(*)�4N7�� � ���������(��� ��> � � + )�*�*C��F � � ��)L�D7����"�3� 4 > ���7?�3� + � �D������ ��<��#�� ��> ���&� � �(���8������ �����3� KT���� �* > *C�3� � ! � � )��3�A4 �-7�� � ���"��� � + ��)#F � � � �D*L�38-�(�A�����3� KN���� � ��� �3)#�* � ���-7_�����J1H)�� � * ����3�_���.� > 7"� 'N���3�.���9�'� *C� ���f���-7 �8-�����#�������46�3) � ��8�)�*J� 46) �-7m��� 8 �� ���-*�(O�38�������46)#������R�D*R7����S �� �O��)f7����"��*J� 46)�� � *A)�4[7�� � �����9�38-�(�&8-�����9�)#�3���(* + )��-7������_��'N�(���*A)#�@F-)#��8* > *C�3� � * ! GH8��(*J��� �(*C����)��-*����3�[������� ��> ��7�7����(*3*J�(7 � )����������h�����D*C�(7-/;�'� � �(*C�')#���'���I*C� 7����:*�(�3�(*J�(����08��.��* 8-�����L�����-7��:7 � �(�H�38���*U�:��� �'> *C�����#�A)(4P���3��� KN���� � ��� ��� � �����J1�)#� � ���(*C�:�����8 � �3)�#7�) + �I� � 7�� � ���#�&�'�A���7E*J��� � � +�+ ��)���08j��) � �(*J��)#�������S*J� 7"���(* ! ��������) *O����1 � ����8�)"7�*)�4 � �(*C�')#���'���A�����J1H)�� � *;8-�����5F-�����b7������ � ) + �(7R)(����� ��8�� > �(����*\15�'�38&�'�-��3�:�#*C�'���A��������� ��� > ����-7 � ��� > )�4���8��(*J�?1����3� � +�+ � ���(79�'� ��8�� � � W# *C� 7 > !

����� ��� � �����% ������!&

GH8��3����)�4 �38�� � �(*J��)#�������O���(�8������ �(* *C�(7RF > � ��'� �'�-������� ���-7 � 8-�(�3��� � ��W�W# / 1H�.�3�5�8�)M*C������-7I� +�+ � ���(7 �3) �38�� + ���(*C���"� �����J1H)#� � ! GH8��:*C���3�(�8���� � �(*T1����3���8�)M*C���AF-�(�� *C��* �S��'���"�����46)�� � �(�3��)��&15��* + �3)(���D7��(7R�'� � � W� ��)A�3� + � ����(�3�5��8�� � �.<����� �'> � �(�-79� � *C)AF-�(�� *C� �38�� >1H�����O�38�� � �(*C�')#�-*H��8-��� + �3)(�"��7��:7`��8�� � )�*J�H�'�������3�(*J�3�'���R���(* �� ��*H�'� � � W� �!

GH8��?K-��*C� � �(*J��)#�������h�3�(�8���� � � *C�:7 15��* � e���� � � d0e� &o���c��XgH�38��Q* > *C��� � ������L��� � )(��� �

Page 153: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� � ��� ��������� � � ������������������� ��� ����������� ����������������� ����� �

)�4]�(��089�'�-7��'���D7 � � 1�������8������b�38��O�����(�����(7h�����J1H)�� � ! GH8��D*U�3�:08������ �L1 �#*H� � + � � � �������(7F > *C�����3�'���&�(�#�8S1H���'�#8"�H��� �' �A���9� �3�S��) ���.�3) � ���- �� 7��'��� ���'�HF��D�#*J�(*0/ ! �O*��38��.�3�A1H������ ��� 1H�.���#8"��* � �38��D*H�3�(�8���� � �L�������������3�:7 � ����� �(*C�')#���:7������J1H)�� � * !

GH8��A*C�(�)#�-7����(�8������ �51 �#* � ��� ��e0p �"p"����d0e &o���c�� � 158����8�1 �#*H� � *J)&7�)����A* > *C��� � �(�3��=�� �'��> g �(�#�8&)�4 �38�� � 8��D7�7���� ������*]15�#* ��� � )(���(7 � )���� �����L��� � � ! GH8�� �#�� � � � �3� � )(��� � �15�#*]� � + � � � �����J�(7 F > *C�.�3�3�'���[� ��� 1H�.���#8"��*2� � �(�-���������546�3) � �L���������A8��D7�7���� ���'� �3) �.���3) ��38�������F > �3� � )(���'���S� �'� ��� � ���-��h)�4 ��8-���I8���7�7"��� �����A)#� ������*?�'�E��8�������<�� � ) � + ��/� � > ��� ! GH8���* + �3)"��(7 �3�A�3�:* �� �3�(79��� � � �(*C�')#���(7h�����J1H)�� � * + �.�L�������'���(79�����J1�)#� � !

GH8��^K-�� �-� �(*J��)��������A���(08������ � *C�(7&15��* ��� o # c��Nd�e � c�� ��p � ! GH8���* �3�(�8���� � �5��* � �:���"��3)@*J� �h �� �(�3�B�E��� �3)#�����(�-* � �'�3������� � F� � �(�-�� ��� ! � 8-������� � + �.��*C)��-� � �) �9�h ���'�������)�� ��# ���> � � ��W�W# / ! � ��� 1�������8���*A���3� �� �� �3� + � � �(79F > � � * � � �'� /5���(� � � �� FT�.� ! �H�(�� *C�&��)* + �(�� KN �� �� �3� + � �'��� ��� �� �(* 1����3� �#�'�����&��� � � W� � Y2� � + � � � ���"�3�(7O� � )#F� � �3�(*��� � �����A�'�&�38��46) ��� )(15�����A15� > g2)#���O8 �-7"�3�(7R�����-7�) � ���(� � � �� FT�.��*21H�����L�������������3�:7 F-���J1H�.���&= � ! � ���7 � ! � ! � �#�8@�����7�) � � �� F-���A15�#*&*J� � �:��3�(7_)#��� � ���-7j������� > 1H���'�#8"�R�'� ��8��9�������'���(7�����J1H)�� � 15��* �h �� ��� + � � �(79F > ��8���*A� �� F-��� ! GH8���* + �3)"��:7 �3�h�3�:* �� �3�(7_��� � � � � �(*J��)#���(7�����J1H)�� � * !

����� ��� � ��� � ���!&

�^46�3�����(��08h���7����"��7 � ��� �(*C�')#� � �38��O�����J1H)�� � 1 �#*U���(*C���(7&F > + ���(*C�.���������I�38�� 158�) � �O�3�����'��=�����h*J���5�3)h��� ���-7B�#*3*J�(*3*J�����h�38��R7"� 'N���3�.�-��O�'� + ���J46)#� � ���-��L46�3) � �38-�(�L���(�)���7��(7S�(�5�38��� � � �(*C�')#���:7T/ F-�#*J� � �'��� � ����� � ! �]���C46)�� � �(�-��&15��*R��*3*C�:*3*C�:7E���f�3��� � *O)�4 �38��9� �� F-���O)�4���3��)#��*U46) �-7S)#� � ����� �� ��� � ���-7 � �.<��� + �3�')#� � + �(�3�3�.�3�-* ! � + �(�3�3�.�3�S15��*L7��.� � �(7&�3)&F-�A������3��)#� � 4��(� > ) � + � �#�������������)#�B� � �D������(7�F > �38-�(� + �(�3�����3�_1 �#*5��) � )����#�.�L15�'�38��'� � ! � )�4�38��A���(�3�����5��� �� � ��� !

����� ��� � �����"# ���

� 7�) F � �97��D*3*J)"����(�3��)��E)(4[*C� � � � ��� � ��������� 7��&�3)B�38-�(�A�3� + )#���3�(7f��� � � W# 15��* 46) �-7 !% ��� � �(*C�')#� � * + �(�� KT�� �'��> � � � )�F-� � �3�:*3�� � �����&F > �R4k�#���)#� )�4 �#!�� �� / � �(79�3)b� � ����� � )�*3*

�����������������! ��"�#�$��% �'&��!(�)* #+�,.-/-/0213%4�5%6�87/(:9�;<)>=��@? �A(�&�)B�C �=D7/ � �)>=�(���)*9�9E=� ���(�)* ��C72� �49�76(�&�)#;��!(�(�)* ��F=� ���(�)DG ���7/�H�89�)>%�(�&� �72��I/&87/��(:(�&���9:(�&�)*9���9�J:�!9'��(�������K*)>%ML

Page 154: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� � � ����������� � �� ��

)�4 ��<��� + ����)��-* � 158�� � �b� 'N�(��������B)#� �'> !$ � )(4 �3��� �� �(� + �(�3�����3�-* ! � ��)#��8���� � �(*J��)�� � �38���3� � )(��� � )�4 �38��h1H�.���#8"�OF-���J1H�.���_��� + � ����� ���7E8���7�7���� ���'� / �������b���f) +�+ )�*J������3�(* �� �.g �� ! �� )�4 ����� �� ����* 1����3� � )�*J� � 158�� � �h� ��� ��<��� + ����)��-*L�3� � ���'���(7 �-*������8��(7 ! �O*����BFT�I*J�����946�3) � V]��� �3� !'� � � �38��(*C�OK-� �3�(* �����A����� > *J� � � � �(�U�'� � ��������� 7��A�3)h�38�)M*C�46) �-7&��� � � W� �! �L�7 � ���"�3�.�3�(*J�3����� ��> � � ���� ���-�(�3��� ���7 � 8-�(�3��� � ��W#W� /\� � *J)A�3� + )#���3�(7R��8-������515��*L�h� � )�F-� � �3�:*3�� � �����h���-7B� 1�������8��5��� � )(��� � � c�� .o?F-���J1H�.���B��� �'� + �[���7 8��D7�7���� ������/��38-�(� �� *C�(7S�38����'�57�) F � �&7��D*3*C)"���������)�� !

Replication with dynamicexceptions

regular patterns exception patterns

Post-lesioning errors

on

Bullinaria & Chater (1993)

41.5%

96.9%0.0%

0.0%double dissociation

0.0%

6.3%

46.6%

100.0%double dissociation

V;��� �3� !'� � g � �) � + �(�3�D*C)#�S)(4 ��8��I7���*�*C)"��D���3�')#�-*H46) �-7 �'� �J1�) � �(*J��)#���(7���<"� � + � ����*U)�4�38�� � ���� ���-�(�3�D�O���-7 � 8-������� � ��W#W� /����.�C1�)#� � ! GH8��^K��*C� 7�) F � �[7���*�*C)"��D������)#�b��* �38��[FT�:*C�)#��� �3� + )��3�3�:7 �'� � ��'� �'�-�������O�(�-7 � 8-�(�3��� � �.W#W� / � 158�� � �5��8��[*C�(�)��-7&��* �38-�(�U46) �-7&���h�38��+ �3�(*J���"�5*C� �� �� ������)�� !

����� ��� � � ��� � � � �% �

GH8��R��)�� � )�4��38��D*L*J� �h �� �(�3�')#�91 �#*L��)����(*C) � ���R��8��&� +�+ �(�3���"�O�)#� �-�D�� ��� K�-7�������*�g Y�15�#* �-��F � � ��) K�-7l�(� >@� )"7 �� ���h*J�3� �� �3� �'�@�38�� � � W# �����J1H)�� � � F � � ���� ���-�(�3�D� ���7� 8-������� � �.W#W� /h�3� + )��3�3�:7l�j7�) F � �_7��D*3*C)"���������)��m158����8m* +�+ )�*J�(7 ��> � � + � ���:*?���"�3�.�3�-� �� )"7 �� ���3�'� > !

YZ�A15��* 46) �-7E��8-���I� �����J1H)#� � �38-�(�R8-��*?��) � )"7 �� ���A*J�3� �� �3�&46)#�R8���-7 � �����B�3����= �� �(��*O�(�-7 �.<��� + �3�')#�-* � ��� � �(�#*J� � ��*L4k���I�#*O�) �� 7 FT�b�#*�����������'���(7 *J�����b�38��h*J��������*J�3��.� ����D* � � ���:���3�')#�_���(08������ �(*�� � � �(�-7 � � �?/ � A�(F � �9��)B7�� � )��-*C���������9�S*J���(�(F � �b7�) F � �7���*�*C)"��D���3�')#�B158���� � �(*J��)����(7 !

GH8���*?���(* �� � � � � �38�) ��8@7�� � )��-*C�����(�3�(7_)#�j)�� ��> )����9���.�C1�)#� � � * +�+ )#�3��*&� ���3)(15�����* * + ����')#�@���a�38�� � ���3�.����� �3� � ! 4 ! � �_�����8 � �(� � ��W�W � ( � � � � � �'� + ���(*3*�/A�38-�(�9�38�� � ��� �

Page 155: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� � ��� ��������� � � ������������������� ��� ����������� ����������������� ����� �

FT�.�C1������ 7���* + � � > ����� 7���*�*C)"��D������)#�* � ���7i8�:�"�����_���@�'�������3�-� ��� )"7 �� ���&*J�3� �� �3� � ��*&��3��� ) *H)#��� !

� )�1 � �38���� � ��*&��� + )�*�*C�'F � � 46)��9�j7") F � �_7��D*3*J)"����(�3��)��l��)@������*C�B���a�j* > *J�3� � ��8-���� +�+ �(�3���"� �'> 8-��*���) � )"7 �� ���h*C��� �� ��� � GH8���*RK-�-7��'���E1�) �� 7l� +�+ �(���h�3) �)#�"�3���#7��D���)#���R��*3* �� + ����)#�* � �#7��[F > �)#�#�����3�'���O��� �3) + * > 08�) � )��#��*J��* !

� �-*C1����3�'���A�38��D*&� �(*J�3�')#�h��* F-� > )#�-7&�38��O*��) + �O)(42�38���* �38��:*C��* ! � ��Y .���b* ���#�(*J� ���� �(��*C��)#��� � ����8�)"7�) � )#������ � ��< + � �(�-������)�� ! �5�(�� ��� ��8-������)I7�������� � �(7R��� + � �D�������)��&)�428 �� �(�� �(*J��)#�������@��* � > ����/ + )M*3*C�'F � �f��� �)������(�����)�����*J� �����J1H)#� � * � 46)�� ��������) * �3�:�#*C)��-* ! GH8���*� �# �-�O8-�#* � �(7R��)I� � ���-7R)(4 � *3.���3�����3� � � � +�+ ��)��#�89�'�9�)������(��3��)�����*J� � �:*C��)��������A*C� 7����:*�g�� �� �3� + � �9�����J1H)#� � *b���3�_�����(�����(7m�(�-7 � �(*J��)#���(7 �'�m� �� ���3) * � �� ��Ce &c�� � � 15� > * � � ! � ! �������� > *C�'��� � �O1H���'�#8"��FT�.�����I�3� � )(���(7R)��-��#/ ! GH8��D* � �.�38�)"7�) � )�� > ���� � �(�#7h�3)R��8�) *3���7�*)�4 � �(*J��)#���(79�����J1H)�� � *HFT�.�����&�������������3�:7b46��) � ������� > )#�����#�'�-� � �����(�����(79���.�C1�)#� � !

YZ�A��* + )M*3*J��F � �9�38-�(� � �38��3) �#8 � �(*C�')#���'��� � + ��� �h �����3�')#�-* )�45��8��h1H���'�#8"� � �����3�'< � � >FT� ��3�(�(�3�(7R��8-����� � + � � � ���"� � � +�+ �'����*;158����8&�) �� 7&F-� ��p �Ce0d �Nd�e �Ce��5��*U7"��*3*J)"����(�3�')#�-* ! Yk4�C1�)A* 08 + ��� �� ��������)#�* 1����3���3)O)"� � 46)#� ��8��5)#���5�����J1H)#� � � �38����h�(�h� +�+ ���3�.��� � 7�) F � �7���*�*C)"��D���3�')#� � 1�) �� 79FT�I�3�(�)#��7"�(7 !

Y,4 �)��3�3�:�� � �38��h��F-)(���9* +�+ )�*J���3�')#�j1�) �� 7 � �(���B�38-�(� � ���������_�.��) ��8E�����(�����(7_������=1H)#� � * ���7 � �(*J��)#�������h�3�(�8���� � �(* � )#���Q*C8�) �� 7 F-�&�(F � �I�3)&K-�-7_7�) F � �&7��D*3*C)"���������)��-*L)�4*C� � � � �(� � ��������� 7��OF-���J1H�.��� c�d # ���kd3c�d��5*C����*H)�4 � �3��� �� �(� � ���-7 � ��<��� + ����)�� � + �����3�����-* !

�[*2� + �3� � � � �'�-��� > ���(*C�2)(4���8���* 8 > + )��38��(*J��* � ��8�� � � +�+ �����5���3��)#��* � �#7�� F > �38�����<"��*J�3������ �(*J��)#���(7������J1�)#� � *H1H�.�3�bd0e�� ��p �Ce0d �Nd�e �Ce�� *J�����h� � �3�.�3�-�(�3�I*C����*^)(4��(�3F��'�3�����3� ��> 7"�(*C�'�#�-�(�3�(7*C����*H)�4 � � � � �3�.� �� ��� � �(�-7 � � ��<��� + �3��)�� � + ���3�����3�* !

� ���� �'�-�������9�(�-7 � 8-������� � ��W�W# /I�8�)M*C�h�3)_7"�(*C�'�#�-�(�3�S��*R��<��� + �3�')#�-* �38�)M*C� + �(�3�����3�-*�38-�(� *C���(�3���(7915���38S��8��A�����'�3��� � F��'��* � ��� ��� � �(�-7 � �#���#� � ! � <��� + �3��)��-*H1H�.�3�A7���K-���(79���b�38�� �3�����"�5��< + ����� � �.������� ��*J� � � � �(� � �(�������.gH� ��� + )�*�*C��F � � + �����������M*L)�4 + �����3�����-*^15�'�38B�38��*3� � � � �����'�3��� � F�����*?1H�.�3�h�#�����.�������(7 � � ! � ! � + ���3�����3�*R*C�������3�����_15���38 � ��� ��� � ���-7 � ��� � � �1H�����97��:*C�����-�����(7@�#*A��<��� + �3�')#�-*�( �38��.� � � ����� � ���-7 � ��� � � � (H�(�-7@*C) )�� / � �����"����� � � � � �

7���*J�3�����A � �#*3*J� KN.���3�')#�-*O)(45�38��&�3���(�����'���B*C���A�'����)S* F*C����*?)�4 � ����� �� ��� � ���-7 � �.<��� + �3�')#� �

��� &:&8)* �)#�! �) , � %4��� )B �)*�4('9�)*(�9:7!?��E9�(��! �(�����I ����(�9 �4J:&��5=�&H�$ �) (�&�)*���! � ��!�8I/)>% �C�4(�7 �!���<;�729�9�� ����) I/ �72��;�97$?�� �4&�)*��=�)�� , �� ;<7/9�9�� ����)E=��5�!9�9���� =*�!(���7/��9.L

Page 156: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� � � ����������� � �� #

+ �����3�����-* !GH8�� � � +�+ �'���R�.�3�3)���* � ��7��OF > �38�� #W 7�� � ���#�:7������J1H)�� � *H�#���������(�3�(7S��F-)(���A1H�����

�38���� �3��=6���"�3��� + �3�.�3�(7 *C�'��� ��8��(*J�9��)(��� � � ��*3*J� KN��(�3�')#�-* ! YZ�"�3��� + �3�.�3����� ��8��9�����3)���*?������=�����(�3�(7lF > �W �����J1H)#� � * *C�'��� � ��� + �����3����� � �#*�*C� KN�������)��-*��#�'���(*9�j�3)���� � )(4 � ��� ��) � + ���3�D*C)��-*L���B158����8_)#���h����_���(�)#��7 �38��&��� � �(�3�'���?� �� F-���5)�4 � ����� �� ��� � ���7 � ��<��� + =�3��)�� � + �����3�����-*R7�� � �(�#�(7 ! � 7"��*3*J)"����(�3�')#�j�D*?7"��� � �(7S�3)B8-������)"� �3���(7 � 4 � )#�j)����9)�4�38��(*J���) � + ���3�D*C)��-* � *C�'�#��� KN����"� �'>O� )��3� ����� �� ����*;�(�3�57�� � �(�#�(7O�38���R�.<��� + �3�')#�-* � )#�]���D��������*�� / ! Y,42�J1H) � �(*J��)#�*U.� *J�O) +�+ )M*C�����A7��D*3*C)"���������)��-*\46)��5�?��������� + �(�3�3�.�3�S � �#*�*C� KT�������)#� ��38����B�h7�) F � �I7��D*3*C)"���������)�� ��*H���(�)���7��(7 !

�_�(� > * � � �'� 7��D*3*C)"���������)��-*L1H�.�3�?46) �-7 ! �L)(1�������� � ��� 15��*O7��(��D7��(79�3)h�3�:*C�3������ �)#��=*C��7"�����(�3��)�� ��)�)�� ��> �38�)�*C�I�38-�(�O1H�.�3�A)�4�� � � � )�� � �����#���[*C� ���A�3)b7���*�*C)"��D���3�')#�-* � > + �D�� �'��>�3� + )#���3�(7_���_��8�� � �(*J��)#������� � ���������(� ��� ! % + �(�� KN�� ����> � Y^)�� ��>_� )�) � �(7_�(�&7��D*3*J)"����(�3��)��-*O���158����8 � )#���O�38-�(� � ��� )�4�)���� + �����3�����_* F-*C�.�L1 �#* 7�� � �(�#�(79������* * � �(*3*5�38��� � ��� )�4�38��A)#��8���� * F-*C�.� !

V�)�� )(4��38�� � � � + �����3�����_ � �#*�*C� KT�������)#�* � c�� �'e�c��� � )#����=,1 � > 7"��*3*J)"����(�3�')#� )(4��38���*� ��������� 7�� � )��9�#���(��������/I15��* 46) �7 ! V�)#� )�4I�38��(*C� � *C���:��F � �_7��D*3*C)"���������)��-*���� # o��$�7������(��3�')#�-*A1H�����9������� �3�(�)���7��:7 gS7�) F � �B7��D*3*C)"���������)��-* ! � * ��9� ��� > )�4[�38�� + �(�3�����3�*C����*U46)#� 158����8S7�) F � �I7��D*3*J)"����(�3��)��-*51H�����L46) �7 � �(�-79�38��I*J�����A)�4P�38�)�*C�Q7���*�*C)"��D������)#�* ���*H�#�'�����9�'� G]��F � � ! � !

GH8��O7�) F � �O7��D*3*J)"����(�3��)��-*U�'�9G]��F � � ! � �(�3�[* � �'�#8"� �'> * � � ��� ���]��� � ��������� 7��5�3)I�38�)M*C��3� + )#���3�(7_��� V;�'� ��� !�� � ! � )��3� � 8�)(1�������� � ��8-���A�38��(*C�h����1 7���*�*C)"��D���3�')#�-*A1H�����R46) �715���38B�3� � ��������� �'>�� ���3� � �O��' )��3��( F > ��<�� � ���������On *J�&o�p-e5�����J1H)�� � ��8-���O1 �#* � �(*C�')#���:7`15�'�38)#� �'> �$��d�e�eL)(45�38�� � �(� > + )�*3*J��F � �9�3�:08������ �(* ! � )#�3�h��<"�3���*C����� � �(*C�')#���'���S)#� � � ���3������ �� F-����)�4������J1H)#� � *H1�) �� 7S� ��� )�*C� ����������'� ��> �#�'���A�������S*J�3�3)����#�.�O7��D*3*J)"����(�3��)��-* � � !

% �a�38��SF-��*C��*&)�4 �38��(*J�S�����'�3��� � *J� �h �� �(�3��)��-*?�'�h*C��� � * � � � � �'> �38-�(�9� � �(�3�#�B� �� F-���)�4 7"� 'N���3�.���A7"��*3*J)"����(�3�')#�-*I����fF-�9��<"�3������3�:7 46�3) � �(� > �)#�����:��3�')#���D*C� � )"7"� � � ��������� �* �`����.���I� �� F-���A)�4A�����(�����(7j��<"� � + � ����*A���-7@�3�(�8���� � �:* F > 158��D08@��) � �(*J��)#�@��8�� � !GH8��&7��D*3*J)"����(�3��)��-*L��� + )#�3���(7 8������R1����3�`p�o�� �� *C�:7 F > ��8��&*J� � �:��3�'��� � �(*J��)��������h)�4 7 � �

��� � =�7��A;��! ���9�7/�#J:��(�&�(�&�):�4��� �<)* M7!?<�C)B9���7/��93=*�$ � ��C).%E72��( ��� ���������C�<�! ��5�:�$��%��'&��$(�)* '+�,.-/-20/1M��9 ���4? 72 G(������$(�)*��� ��7/(3;<7/9�9�� ����)���$93��7E����%4�5=*�$(���7/� ��93I/���2)*�6���6(�&��$(3;��!;<)* '7!?M&�7!J�� �$� ����)*( J'7/ ��49'J )B �)���)*9���7/��)>%(�7H�/=�&���) �2) (�&�)# �)*;<7/ �(�)>% �)B9�����(�9.L - (:��9��4��7!J:�H(�&��!(:(�&�) �A��9�)>%�� � %4��� )* �)*�4(���)*9��C72������I (�)>=�&����� 2��)*9.L

Page 157: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� � ��� ��������� � � ������������������� ��� ����������� ����������������� ����� �

G;�(F � � ! � g � ) F � �I7���*�*C)"��D������)#�*U46) �-79�'�S� � �(*J��)����(7���<"� � + � ���P)�4P�38�� � ���� �'�-�������A���7� 8-������� � ��W#W� /����.�C1�)#� � � )#��7������(7�F >�� �(�#���'� 7"� ! GH8��LK-��*C�5�) �� �� ����� + )#����*U��8��A7��:*C����=�-�����(7 ��<��� + �3��)��-*U)(4��38�� + ���3�����3� *C����* � ����� �I � ��*3*C� KN��(�3��)��-*H)�4\�38��A�3�����'�������b*C�.�5���"�3)���3F����3����� > � �3��� �� �(��* � �(�-7 � �.<��� + �3�')#�-* � /H46)��R158��D08f�38��b* + �(�� K-�(7 7�) F � �b7���*�*C)"��D���3�')#�-*1H�����O�3�(�)#��7"�(7 !

�;)�*J�3= � �(*J��)#��������.�3�3)���*H)��

� �:*C�����-�����(7 �3�.� �� ��� + �(�3�3�.�3�-* ��<��� + �3�')#� + ���3�����3�*� <��� + ����)�� �P���3�����3�* � �

� � � ��!�!�! �.W�! � � ��!$ �#� � ��!�!�! � �!�� � ! �� � � ��!�!�! � �! � � ! �� � ��� !�!�! � �!�� � ! �� � � ��!�!�! � �! � � ! ��#� ��� !�!�! � �!�� � ! ���� ��� !�!�! ���#! �� ! �� � ��� !�!�! �� ! � � ! �� � ��� !�!�! "! �� !$ �#� � ��!�!�! � �!�� � ! ��#� � ��!�!�! � ! � � "!��� � ��� !�!�! � �!�� � ! �

Page 158: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ����� � ��� ��������� �� �

+ �3)"��:*3*C�'��� �3) �3�(* � F �2�����38����;F > ��8��H�������������3�')#�I)�4N� � �(�3�#��� �� FT�.� )�4 � )"7�� K�(7O1H���'�#8"�� �����3����(*L158��D08f1H�����9�(F � �h�3) *C� �� �� ����� � � +�+ �����SF-��8-���"��) � ��p �Je�d �Nd0e �kc # ��eI�#*I7�) F � �7���*�*C)"��D���3�')#�-* !

����� � � ��� � � �������

Y �B�38��D*L�8-� + �3��� � ��8��R����������� � � �'��� ��������� ��)#����)#�_)(4��$��<��� + ����)��-* � 15�#* ��< + � )#���(7S���-7 46)��3=� � � �����(7�46)��O�38��h�)#�����:��3�')#���D*C� + �(����7���� � ! YZ�O1 �#*L46) �-7 ��8-���A��<��� + �3��)��-*5�����(7 ��) F-�7���K-���:7 15�'�38f�3�(* + �:��O�3)B�J1H) � � +�+ �����M*�gO��8���� �)#���3�(�� �-� � +�+ �����S�(�-7j� + �����3��� � �$� �� � �� � +�+ ����� ! �H�:�� *J�A��� ��* 7�� �` �� �5�3)S7��.�3��� � �����[�38��I� �� � � � +�+ �'���h� � + � � � ��������7hF > ��)#�����(��3�')#���D*C�A�����J1�)#� � � �'�A��*A7�� �` �� �A�3)_7"���3��� � �����R�38��9*J���R)(4 ��<��� + �3�')#�-* ! � �#*J�R����=*C�(�(���8�����*H8�:���I��'�� �� ����������7&�38���* + �3)�F � � � F > * + �(�� 4 > �����R��� �#7����(�-��A158����8S� �� �A�38�������J1H)�� � 15� �'� � �(����� � ���-7S7���K�������I��<��� + ����)#�*U15����89�3�:* + �(����3)&��8-���5� �� � ! YZ�9��'N�(�� � �38��� + �3�')#�3����)��3�')#�@)�4[��<��� + ����)#�* 8�#*RF-�����j�����(�-* + � ���"�3�(7 � *C) � ��158-���Q��1 � 1 ����7 ��>� �3)�38��I�)������(�����)�����*J�5*C� �� �� ������)�� + �����#7��'� � !

Y 8-����� � ���-*J�3�(��7 � ��7������-��:7 �A��)#����)��9)�4]��<��� + �3��)��-* �38-�(�5��* � )��3�[* �'�3�(7���)R��8��O�)#��=���(�����)#����*C� + �(����7���� � ! � <��� + ����)#�*?�(�3�S7"��K-���(7_15����8j�3�:* + �(��A�3)B�38��b�#�� � �H� � +�+ ������ � + � � � �����3�(7&F > �38��I�����J1H)�� � �(�O�h�#�����.� ��� � � � ! YZ�L�D*H��)#�O���(��(*�*3��� > �3)`08-�(������3���������158-���A�38��� � � +�+ �'���9�D*�(;)����h�����(7 )�� ��> 7��.�3��� � �����A158��D08 + �(�3�3�.�3�-*A��������)#�I�)#���3�(�� ��>8-���-7 � �(7 F > * �8_� � � +�+ �'��� ! GH8��h7 > �-� � ����'� > )�4 * 08B��<��� + ����)#�*^1 �#*O� � *C)B7�� � )#��=*C�3�������(7 gH���.�C1�)#� � * � �(�����_�&�������#�&)�4 � � +�+ �����M*H)����.� 7�� 'N��������� � �(���������������3��� � * � �� *J�������7�� 'N���3���"�5*J���5)�4\��<��� + �3�')#�-*��3)b������*C�A�(��08b�3� � � !

YZ� ��*O�b�) �9� )#� + � �#��[��� ��8��h�)������(�����)�����*J� � ���3�.����� �3�A��8-���O)����h��(����)#� + ���(7��D��5����#7��������R158-�(���X� �� � � � )#� � � +�+ �����"/�� �����J1H)#� � 15� �'� �'�-7 ��O46��) � �&�#�'�����S�3���(�����'���h*C�.� ����-7A�38-�(�2� �� �(* � �(�(�3���:7O����I����� > )����.� �h �� ��� + � � � �(�(�3���'���5�3����� � * ! GH8��D* �3�(� � ���:���3�')#�A8-��* � �(7�3)h�38��I15��7��(* + �3�:�#7S�#��� + ���(�-��A)�4���8�� � � �l� �(����������� + �(���#7"��� � � �H� � �D���"� � ��W �� / � �(�-7 ��#*&� + ���#��3��.� � �)#�-*J� � ���-�� � ��8�� *J�9)�4 ��e�pTe0d3c�� ��.c�����o�p �Je �����p � )��j�3���������(7E�����J1�)#� � *�3)h�)���K-� � �38���H��8��O��< + �(����(7 � � +�+ �����?8�#*HF-����� � �(�������(7 ! GH8��A�) �b� )#�h��*3* �� + �3�')#��38-�(��)����B���� + �3�(7"����&��8��B*C���&)(4A��<��� + ����)#�*R���a�#7����(�-�� � �'�-�)�� + )#�����3�:* ��8��S� � + � ����'��#*3* �� + ����)�� ��8-��� )#��� � c�p&� � *C) + ���(7�����5�38��A���7 ��(7h� �� �?�'�B�#7�������� !

YZ����* + )M*3*C�'F � �A��8-���5��8���*�� + �3�')#�3� ��������#)��3� �(������)#�S)(4 ��<��� + �3��)��9�(�-79�3��� �� �(� + �(�3�����3�-*

Page 159: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� �� ��� ��������� � � ������������������� ��� ���������� ��������� ������� ����� �

� � > 8-�����RF-�����_��8��h�� *C�&)(4H��8��h�)�� �-����3�����9�(�-7 � � �'��)"�� � ���(* �� ��* )�4 *C� 7����:*L���"���(*C=�3���M���������S�38�����<"��*J�3�����R)(4 �S7 � � ��) ��� ! �L�f��<�� � ������3�')#�B)�4 �S�3���������(7 �����J1H)�� � 15�#*������3���:7R) � *C�'���A�38�� + �3) + )�*C�:7 � ���#p�c� � � ��)��3��)��9)�4 ��<��� + ����)#�* � �(�-79*C��� �'� ��)R�.���D7����-��46)#���O7 � � ��) ���515��*P46) �-7 � ��) + �3����� + � �(7O�3� + �3�(*J������������)#�� � 7��D*C�����-�����)��R15��* 7������(����(7FT�.�C1������ � 7 > �-� � �D�/ ����� �� ��� �(�-7 �.<��� + �3�')#� + �(�3�����3�-* !

�[���h���3�'�#)#��) * + ����8 � YH8-�����I�����3�����:7 ���[�38�� + )M*C�'�3��)�� � )�����8�� � 7SF >S� �(� > �)#�����:�=�3��)�����*J�A�3�(*J�(����08��.��*�gO��8-���Q� ����� �� ����=,��<��� + �3��)��f7���*J�3�'�-��3�')#�_�D* ��)#�R�.�-�)"7��(7_F > ��� ��� ������J1H)�� � *^��8-��� � � + � � � ���"� � ��*C������� �� ��� � � +�+ ���������#* � *�(N���7 8����-��I�38-�(�O7 � � ��) ���(*���3�[��)#�5� � + � � � ���"�3�.7RF > �)������(��3��)�����*J�������J1H)�� � *U�3) � � + ����� �� ��� ���-79��<��� + ����)�� + �(�3=�3�����-* ! �L)(1H������� � �38���* + )�*C�'�3�')#�9�D*\��)�1mF�#*C�:7�)#� � )#�3� *J) � ��7&�38���)��3�������� � �#��) �7 gU�'� �h>���"���(*C�������(�3�')#�-* Y]8-�����O � )�*J� ��> ��<�� � �����(7R� ��� �38�� � �)#� �-�D��3�'����/ �����D7����-�� �:���(� � �(F � � � �3�(7"��=K-���(7R��8��H��)��3�')#�h)�4N��<��� + ����)#�* �'�&�L1 � > �38-�(� ��*]* ���3�:7R�3)O��8�� �)#�����(�����)#����*C� + �(���#7"��� � ����-7 *C�(79*J���(�3��*J�3�D�� � �"��* � � � �(������)��&�3�(�8���� � �:*;�3)Q7������(�� �'> ��<�� � �������38�� ���"�3�����-� � *J�3� �=� ����)(4[* �8E�����J1H)#� � * ! GH8��b7�) F � �b7���*�*C)"��D���3�')#� + �3���"��) * �'> 46) �-7f���f�38��D*?�����J1�)#� �15�#*H��� + � ����(�3�(7 � F � ���B� � �3�����-���������O��< + � ���-�(�3��)���46)#�5�'�515��*5�#7��������(7 g ��8�� + ������3�D��O)�4�� ��Je� &c�� � � � �(*J��)��������Q���� �� *C�I7�) F � �I7��D*3*C)"���������)��-*^��)�)". �5F > 08���-�� !

Page 160: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � ��� ����

� � ����� ��� � � ��� ����� ������� �

����� � � � ��� ���! ����� �

Y �&��8���* ��8��(*C�D*#"��38�� � ��nJ)#�\�)#�"�3����F ����)��&15�#*��3) + ���(*C���"���A7�������� � �(7&�)��-*C�D7��������3�')#�h)�4 �38��� �:*C�3�')#�2g

� )R46���(7�46)#�31 ����7 �)#�����:��3�')#���D*C�H�����J1H)#� � *57"����� � ) + �?4 �-��3�')#�-� � 7 � � �3) �3�����08��'�3�(�� ���L��)�� � + � � � ���"� � �#*J������� �� ��� � � +�+ �'����*%$

GH8��� ��*#""�38�� � �:*C�3�')#�S)�4P158�����8���� �X�3��� �� �(� � �(�-7 �$��<��� + �3��)�� � + �����3�����-*5�����A8-���-7 � �(7F > 7"��*C�����-�� � � +�+ �����h*C�3���������#�'�(*H15����8����B�&�)������(�����)�����*J� * > *C�3� � !

% ��� � ���#8"�5�3�:�#*C)��-��F ��> ��* � 158 > ���38��:*C��* *C8�) �� 7 F-�h7�����)��3�(7S�3)S* �8_� � �(*C����)#�&"�#�����.�&�38-�(�H�38�� � ��nJ)��3��� > )�4]���(*C�:�����8�����*;)#�bFT)��38B*C�D7��(* )�4]��8�� ��7���) � )��#��.� � 7��'���D7�� � ��8-�����*#"N�)������(�����)�����*J��* ���-7_7 � � �3) �3��*J��* � 8-�����&� +�+ ��������� ��> �#*�* �� �(79�38-�(�O�38��Q���-*J1H���[��*)#F"���') *�g��)#�����(��3�')#���D*C�������J1�)#� � *U8�:���[��)h7 � � �3) �3� (��38�� > �(�3� ���p ����eH��) ���I* > *C�3� � * !GH8���* � �(*C����)#�S�D*U46)#� �38-�(�L���(�#*J)#�_���(�3� �'> *C�.�3��) * �'> 7��D*3 *�*C�(79�'� �38�� � ���������(� ���'"���<��� + �)"���#*J��)��-� �'��> ���Q�L*J) � ��158���P7���* � ��*�*C����� � �(�������)( � � � �P���]� � ! " ��W#W � ( % ����7"����F-�����*" ��W�W � (% ����7"����F-�����,+ �_ ��� � ��� ���-7-" �.W � W / !

YZ�a�38��D*R�38��(*J��*hY?8-�����SK-��*J� ��> �(*C����F � ��*C8��(7j�38��B� � + )#�����(�-��B���-7@�3� � �������-�� )(4A�38���*� �:*C�3�')#� ("�3���"���.1H�(7R��8��A�)�� �-����3�����?�.���D7����-��5�'�9�38�� � �'�3������� �3�5)#�S��8���*���*3* ��("���7`��8����YT8-�����������3� � + �3�(7L��)5��<"8-� *J�3�'��� ��> �)#�*C��7"���]� �'� �38�� 4k�#��3)#��* 158����8?8�:������)LF-����� � ���A���"�3)�#��) �"�H�3)Q���-*J1H���5�'� ! GH8��O�#)M� � 1 �#*H�3)I�3�(*J) � ���O�(� �D*3* �O�38��� ����� � ��)(1 8�#*U��)#�5F-�����

�� �

Page 161: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� � ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

� 7� �� � ��� �'> � 7�7� ��(*�*��(7����l��8����������� � ��� �� ! YR1���������)(1� ��������.1���8�� � � nJ)! "��8���)# ������%$ � �$�)!���� ���F������)#�-*&� � 7�'���(�38)��*"�38��(**��*�(+�38��D*& ��������1 1������ � �,��8��f* � �,�������,�S**�� ���� � * �*���,� � > )(4-��8��.$�)!�����/��5)(4-��8��0�38��(**��* !

V��� �**� "���8��1��)!����)!�I)�4 �2 � *��� ���3#�� � 4� � +�+ ����3M*5���.$�)#3!��������)#�A1 � *4������ �)"76$7�:7���� �.8 ��9;:<>=?'@ ! GH8��&7 � �� 3)!)���A��8���)# > + )�*�����*���8 � �B�J1H)C� � +�+ ����3"�D�>$08 � ���D*��S* � ��A���/�(7�(7 �3)8 � �-7����, ���3!�� � �* � �-7E��<)$7� + ����)#�-*#"]158������F��8��'$�)!���)�>$7���')!���D*�� � +�+ 3) � $�8 (e�e A��)f*�� � ����38 � �L)#��� > )#���0�,�>$�8 � �)��*��G�D*H �� ����� ��(7 ! GH8��I*�� � ���:7I ��:*�� � J$�8 �2)�(*�����)!�S1 � *��3)C�������(*�����=3 � ���R158��/�38��� ���8��0�J1H) � +�+ 3) � $�8��(* 7�)*"����`4 � $7� "-7�� 'K�� !

�.8 ��9 <>=�?ML $7N#�� � ���)�(7 � F� �����4O ���������1P��NQ�38)�����/�����JRAN(4.�38��B7 � �� �N!������38��/N! > "���6$7��-7����3" ��>$S������DN"7� KK$ � ����N!�6R���ND�38��IF � R*�%$T��8���N# >�U �N U NVR��(7 F > �W��� � �� (�X W#W XZY � �\[� N!����]�� � ������ � �_^ (�X W#W#` YJ^

GH])�%R � $�$7N#���.a � RT��])���E$SN!���� � R����>[ba�����]E��])�,$7N#�����>$S����N#���%R*� � U�U �N � $c]���� �.8 ��9;:<>=? d ^IGH]��C$7N!�)���>$7����N!�)�%R��B�����*aeN! � R� ��������aH�f[ � ��C[�/�,N!�6R*�� �Zg ��h �>g ���"��N,��� U �����D�7����2 � R��� ���3#�� � i� � U�U ����3�R " � �6[A��]��%R �Zg �������*h+] � R g �����.�������� U ��/���>[ g h g N#��]C$7N#�����>$7����N#���%R*�JR� �6[Q[ � �j �N!���� � [���N�$ � ���>R � R � $J] � �������)3!�"��N ��]��,[� � �1 �N#���� � $/$7N!���� " g �>$ � 6R��DR�\$c]�����*aHN# � R � ��.$7N#�,�,N#����hkR� U�U NVR��>[���N,$7N#�� � ���IN#����h � R����)3!���0 �N!�����^

Y_� �.8 ��9 <>=?.l Y4��m � �,�����>[+��])� g6� R*�%R-NZno��]��pR-R� U)U NVR�������N#�4^�Y�[�����/ ��,�����>[+��] � �1��]��� ���%R���N,� U R�NFn � $7��NC �� � R�N#�b��N g �����������0��] � �+���/� � �i���/��aeN! � R � ��"$7N#�6R��� � �����>[���N � R*����3#�������p � � ��o�p�c��# �N!)���'"!�/�����A��]�N!�3#]F��]���h0� � h0N!����hA] � ���eN!�����"� � �� � c��� �N!)����^ �W])����NVR�N U ]��%$ � �N g n*�>$7����N#�6R;��N+��])�%R�$7N!�,�DN!����hqr]����p[ � R�R�)� U ����N!�.aH�� ��H ��/�����aH�>[�(���]�� U �N g �����s�p[������� K\�>[a � R4��] � �-��]��H�*aHNB�*h U �>R5N>nK�,N�[���pR � �� � U�U � ��/�����h g ������30$7N#� U � ��>[ � ����]��ea� �N#��3+���/�����%RNZn � � � ��h)R��%RS^

G4NQR��� ����)3!��])�����Fh � �3#��,�����A��] � � � [� � �e �N!)��� ����� �H��� � g ����� � ��] � ��)�tnrN! ��$7N!���)�>$7����N!���pR��e��m���� ���N! "�Y1 ��������/aH�>[ � �6[,������� U ������f[& ��>R�����JRjnr �N!� � � ��3#�TN>n-���>R���N!������3��m U �� ����,�/��uRvN#�E$7N#�����>$S����N#���%R*�0�����*aHN# � Rw��] � �.aH�� ��"�� � ���)�>[xN#�E� � ���N!\R �� � R*�� ��/3!�� � � � U�U ����3'� � R � RS^jGH]��pRA ��������/a g �N!�3#]�"��N!3!�/��]��� "WnrN# "��]��hK6 JR*�"�����D�'"�R��� �N!��3 ��p�����d�e � �����p[���6$S�H��] � � � [ � �5 �N#����B�%R-��� U ���/�,�7�����f[w���,$SN!�����f$7����N!���pR��eR�h)R������ R7^-y�N#�,�B���>R*��N!�)�>[�����*aHN# � RFaH�� ��InrN#��6[(��N�[�pR U � � h ��� .o � ��c�����o�p "���] � �,�%R " � R*�����>$S�������D��N�R�R,NZn �Zg ��������h��N $7N# � ��>$7����h � � U ���3!�� � +N# 0��m�$S� U ����N!� U � ������ ��6R7^ % ���kR���6[h ( �H)������� � �� � + � ] � ���/ "X W#W#` YB������� ��>$7N! u[�>[ � ��o�� # ��e ��� .o � ��c�� ��o�p g ���*aH����� ���3!�� � uR � �6[��/m�$7� U ����N!�6R "�a�]��%$J]

Page 162: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ���� ��� � � � ��������� X `#W

[���,N#�6R��� � ���>R���] � �.R����,��� � O[�%R�R�N�$7� � ����N!�)�%R��0�����%[����6$7�"��m��%R*�JRvnrN# � [� � �1 �N#����C��� g N!��]]�� � �6R � �6['$7N!���)�>$7����N!���pR������/��aeN! � RS^

� � �����)3�]��/�6$7�1�>R�� �Zg ���%R*]��>[ � � ����N!� � ���HnrN! ���])�H ��fR�� � J$J] "#Y U �N�$7���f[�>[T��� �.8 ��9 <>=?����N'[�%R�$76R�Rw��]��C$7N#�6R��p[�� � ����N!�6R � �\[b$7N#�6[������N#�6R+a�]��%$J]��C6R*� U ��f$7�>[�.��]��CR*� � u$c]�nrN! �[ � �6 �N!�������� � $7N#�����>$7����N#���%R*�1R�h)R�������^]GH]��B�,N�R*�-��� U N# �� � ��W$7N!�6R*�%[�/ � ����N#� $7N!�\$7�� ��)�>[]�N>a ��N'[�/��pR�� � R*� � u$c]Q�,����]�N�[���] � �0� � [� � R�nr��a � R�R*�� U ����N#�6R � R U � $7���p$ � � �Zg N!��]�N>a � [ � �e �N#����,�D��3!]�� g �,��� U �����C�������/[ � ��])�,�>R�R*������� � �eR�]�N# ��J$SN!�,����3�N>n U �������N#6R�������>R�����3 � �������"�,����])N�[�R7^_Y_�0a � R"$7N!�\$7��6[��>[b��] � � " � �"��]��D���� �h���� � R*� " � �)���*aHN! � a�����]� [� � �0 �N#����QaHN#��%[(] � ������N���� U ���/�F�����CR*N!�,� � ���\[ NZn ��p �Ce�d�p�c�� ��� �����p � ����o�p ���(���JR �� U ��>R��/�� � ����N!� NZn ��/3!�� � � �\[I��m)$7� U ����N#� U � ������ ��6R���N"���nrN# J$7� � �h � ���\[ N>n1[� � �� �N#����U �N�$7�fR�R�����3"(1�tn ��N�[��%R������6$S����N#�ba � R0� � [� "iR*� U � � ��� U �N�$7�>R�R*����3'aHN#��%[ g �,��� U N�R�R�� g ����^G;ND[�����>$7�BR�\$c] � [�pR������6$7����N#� Y1��� ����>[,��N R�� � ���pR����p$ � �4���%R* � ����� � ����N!� ���>$J]���� �2)�>R#"�a�]��%$J]$ � � ������ � �H��]������ U N! �� � ���C[���D���6R���N!�6RAN>n0� � �� � ����N#� ������]���������� �� � �� �� U ��>R*���� � ����N!�&"a�����])N!��B �� ����� ����)3A���B��N g �.R U �>$7� K6�>[,��� � [� � �\$7��� ��c��4��]��%R�[�pR������6$7����N#�I�pRHN! ���o��x�����%R��� U �����C�������>[K^

GH])�>R��"���>$c])��������>RHae�� ��.��]���� � U�U �����>[ ��� � U ����N#�+R*��6[h " � �6[���]�� � R�R��� U ����N!�6R����q[�� ���h����3A��]��0� � ���p[,6R��0NZnjR�� � ���pR����p$ � �4���%R* � ����� � ����N!�,��N�N!�%RBR�\$c] � R � � �saH�� ��T���>R����>[ (����a � RB$7N#��K6 ��D�>[F��] � ����])��h � ��.R � ���%RZK6�>[ g hD$7N!���)�>$7����N!���pR������/��aeN! � RS^

Y_� �.8 ��9 <f=?�� " � nr� ���]��� ���� U N! �� � ����$7N#�6R��p[�� � ����N!�'a � R�[��%R�$S6R�R*�>[ "�a�]��p$c] ] � Rv ���q$7�������f[ ���/ �h������������ � �����/�����N!�Q������]��"�������� � ��� ��kR�NIn � � ��]��"�fR�R��/���� � � U �N g ����� " ������]��R�� � J$J]xnrN# � [� � �e �N!)���'"�NZnO[��K\������3�� � � � � U � ������ ��6RT��� � 3!�����/�b� � R � � ��,��])��� ���3#�q� � � � �6[ � ��m)$7� U ����N!� �5U � ������ ��6R7^SGH])�,���>$J]���� �2)�>R��*h U �%$ � ����h 6R*�>[b���b��]�� $7N#�����>$7����N#���%R*��������� � ��� ��+aH�/ ��.$7 ������p$ � ����hC ���������ae�>[ (���])��h aH�� ��wnrN#��6[ ��NC���6$7N# U N! � ���A��])�A��� U ���p$7� � � R�qR��� U ����N#����] � �FN#���Q$ � � U ��f[�%$7�"��� � [� � �\$7��a�]��%$J]�� � U)U ����3 (rN! � ����� � Y � �����*aeN! �aHN!)�%[����6[\$7�Anr �N#� � 3!���������� � ��������3'R*����^ �vnr���� +nrN! �� � ��� �����)3F��]��F���������������0��N#����N#�ENZn��m�$S� U ����N!�6R "-Y U �N U N�R*�>[ � p�o��(e � o��-e�d�c�� ��o�p�c�� ��.c�� ��o�p"NZn1�/m�$7� U ����N!�6RHa�����]����I��]��"$SN!�����f$7q����N#���%R*� U � � [���3!� "!��] � �e[��K6���fRW�/m�$7� U ����N!�6R4a�����]F ��>R U �>$7� ��N0��]���������� ��D�>[� � ���1� � U�U ���)3� $7�� � ����h+���6[6$7�f[ g hT��]��H�)���*aHN! � ">a�����]�N!)�i �� �2)�� �����3BN!���e��N � ��N>aEa�] � �-��] � �-� � U�U ���)3�%R7^

Page 163: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

�B��������������3 � ��� U �������N!\R"$7N!�6R*�%[�/ � ����N#�6R � RFaH�/��� � R&��]����)��a�N U �� � ����N#� � ����� � ����N!�(NZn��m�$S� U ����N!�6R " � $7N#�����>$7����N#���%R*�T�)���*aHN! � ��] � �"[�pR U � � h��>[�[N! g ���D[�%R�R�N�$7� � ����N!�\RA��� � U ���q���N!6R+R*��6[�h�a � R+��m � �D�����>['$7N!� U ���])���6R���������h"nrN! 0��]��"��m��%R������6$7�.NZn � [� � �1 �N#����V^ � N �� U ��>R��/�� � ����N!� � �4[� 'K�� ����\$7� g �/��ae�����, ���3!)� � � �6[I�/m�$7� U ����N!� U � ������ ��6R�a � R nrN#��6[5^

V���� � ����h " � ��N>������������� U ���� � ����N!�0a � RiR*�3!3#�>R����>[TnrN! ���])��[�pR�R�N�$S� � ����N#�A ��fR�����JR5nrN!��6[0���R�N!�D�B$7N!���)�>$7����N!���pR��-���>R���N!������30R*��6[���>R7^ �H�>$ � 6R���� � �3#������ g �� JR4NZn;[� 'K�� ����� ���>R*��N!�\R � ����h U �p$ � ����hO$ � � ����f[wN#�� �� ��Ce� &c���� � c������j���.R�\$c]kR���\[���>R "!�����*aeN! � g �/] � ���N!� �� ������ � �������4��N� [��%R�R*N�$7� � ����N!�D$7N!��p[ g �B�����p$7�����>[ g h"$J] � �6$7��^PV\) ���])�� 1[�pR�R�N�$S� � ����N#�F���>R��uRWa�����] � g ���� � �hU � ������ ���$S� � R�R�� KK$ � ����N#�6R�R* U�U N! ����>[ ��]��pRH]h U N!��]��>R��pR7^

����� ��� � � ���������

�H]��� �� � �� "�]�N>aH������ "���� U N! �� � ��e�����D��� � ����N!�6Ri��NF��]��+ ��>R�� � J$J],��] � �B] � R g ����� U ��>R��/����>[]��� ��V^��H]��>R*�0] � ��� g ����� �,��������N!���>["��� U � R�R*����3C��]� �N!�3#]�N!)����]��0��]��>R*�%R " g ���])�� ��AY1a��������m U ���%$S������h��,��������N!�B��]��e�,N�R*�4��� U N! �� � ��4N>n6��]��fR��'" � �6[A]�N>aE��])��h � 'K�>$S�i��]��e$7N!�6$S��6R*��N!�\R7^

�H])��$J]�N!�p$7� NZn0���/��aeN! � R"��m � �,�����>[b] � R#" g h����>$7�fR�R����*h'" g ����� ��>R��� ��p$7���>[E��N�R�� � ���R�h)R����/� R&��] � �D��� U �����,�S��.�����,�����>[ �� � R*�� ��/3!�� � � � U)U ����3Q� � R � R7^ V�N# ,��m � � U ���'"1��]���W� � �� � �6[ ��$ � ������� � �6[ (�X W#W#` Y0�����*aeN! � nrN! U �N#��N!)�6$7���)3��W�)3!���pR�]EaeN! u[�R ( ��m � �D�����>[��� � ] � U ���� � Y+$ � �QN!����h�� � U �,N!��NVR�h���� �Zg �p$TaHN# J[�R � NZnea�]��%$J]���])�� �� � ��CN!����h �Zg N!��`����� ^�H])� �H�������� � �� �"� �6[ � ] � ���� ,(�X W#W#` YB�����*aHN# � ��� � ] � U ���� � a � R��� � ���)�>[�N!� � �� ���� KK$S� � �K� � R � a�����]Rn*6R*� � � � �� � �������)3 U � �����/ ��6RS^��+R*����3.�����*aHN# � R � �6[,� � R � RHNZn �����,�����>[$7N!� U ����m����*h,] � RA��]�� � [�� � �� � 3#�IN>n�� � � ����3'R����F�� � ����N!�\R��,N! ��"� � � � 3!� �Zg ���'"4� � R*���� .��N �� U ���%$ � ���'" � �6[0� � R*���� 4��N � � � ��h ���1�tn)��]��/ �� � ��1N!����h � �����D�����f[H��� g �� 5N>n U � ������ ��\R;��N U ��N#��^�H]��BR����F�� � ����N!�\R;ae�� ��'"#���-�C6R�� g ���)N!���f[ "�NZn�$SN!� U � �>g ���BR*�����e��N0��]�NVR��B �� U N# ����f[&���"��]�� ��>$7�/��0�������� � ��� ���( � U � ��Anr �N!� ��]�� � � ���hQ��m)$7� U ����N!�QNZn � ���H� � � � ( �vNVR���� g �� �3 "�X W � � Y%"� ���K����m���qr �� � [����3C$7N!�)���>$7����N!�)�%R��e�����*aHN# � R ( � �6[ "����\$7�%[�/�� � ����h'"!��� U ���/�F�S����>["[ � �4 �N#����R�h)R����/� RcY ] � ���+N!����h g ����� � U)U �����>[,��NC� � U�U ����3.�,N!��NVR�h���� �Zg �p$�aHN# J[�RS^

�H�f$ � 6R*����]��+���/��aeN! � R1��m � �,���)�>[AaH�� ��+R*� � ��� "����1�,��3!]�� g � � �3#��>[,��] � �H��]��+�p[��������qK6�>[�� $ � U ��%$7��N!6R*���>R�R � NZn $7N#�����>$S����N#���%R*�1�����*aHN# � R ( ���,���/ �� RiN>n���]��O� � ������*h"NZn�� � U�U ���)3�R��]���hD���6[\$7�+nr �N!� � 3#������� �� � ��������3CR*���7Ye�%RH�)N!� � 3#������ � � U �N g ����� ^ ����] � ���� � �������/��hR�� � ������ � ��������30R*���-NZno�,N!�)N�R�h���� �Zg �p$jaeN! J[)RWN# U � ������ ��6R#"!���-�,��3!]�� g �B� � R*hTnrN! � �����*aeN! �

Page 164: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� � � � ����������� X � X

��N K6�6[ � R��� � ��3!� � � � U)U ����3' �����>R ( � R"R*�����E��� � ] � U ���/ � Y0��] � �"aHN# � n*6R�� � RAae����� � R��]�� �������/�6[�>[E� � U�U ���)3�^ ]��� �� � R"�tn � ���/��aeN! � a � R&�� � �����>[�N!� ��]��Inr)����$SN! U 6RFNZn�W�)3!���pR�]�aHN# J[�R ( N# U � R*�F�����6R*�>R#"1���J$#^tY%"���]�� o���e0d � �-e!� ��p �ad0e ����� c�d���� �FN>n+��]�� �� � ��������3R����.$7N#��%[Q$7N!�\$7����� �>g ��hQ$7N#�6R��� � ���E�,N# ��"����3!]�����h���]��,R*���0NZnB���6[6$7� g ���"� � U�U ����3�RS^ % ����,��3#]�-��]��� ��7nrN! ��^K6�\[F��] � �H��]��+��m U �>$7���f[FR*���1NZn� ��/3!�� � U � ������ ��\R � 1NZnr�����,��� � ����>[RK6 JR*� "� �6[F��]��B��m U �>$S���>["R*���HN>n4��m)$7� U ����N#�6R1[N U ��>R��/��1��])��� R��/�����>R � Rj��])� � U �N g ����� ��U � ������ ��6R[� �����3+��� � �������3)^ ��N>ae������ ">�������.���"� � �3#���)���*aHN! � R "!��])�%R-$ � ����N#� g �B� � � ���TnrN# j3# � ����>[5^�H]��&n � $7�0��] � �A3#������ � ��� � � ����N#�b���>R�������3 �%R0[�/���,�>[ ���>$7�>R�R � �h�N!� �����*aHN# � RwN>n � ��hQR�� ���[���,N#�6R��� � ���>R���] � �.N!���D$ � �Q � �����h g � R*� ��Ca�] � �0� � U�U ����3 ��]��"���/��aeN! � a������ ���6[\$7�nr �N!� ��]��0�� � ��������3" ���3!���,�'" � �\[I]����\$7�+a�]��p$c]'[h�� � �D�%$���m�$S� U ����N!�6RHa������ � ��pR���^

�B��N!��]��� 1$7N#�6R��� � �����-N!�"��]�� U ��>R��/��-aeN! � a � Ri��])��� � � �N>a� � �)3!��NZn;R�� � ���pR����%$ � ���N�N!�%R

� �6[b���>$J]���������>R���] � � � ��D$7� � ���������h � � � ��� �Zg ���AnrN! .�������>R�����3 � ����N!��NZn �������� �� � � �� U ��>R��/��q� � ����N#�6R7^ ���H��]��%R1� � R�$7�����BR�� � 3!�0NZn $SN!�����f$7����N!���pR��H ��>R�� � J$J] "���N"�������>R�����3 � ��������R*� � ���%R*���%$ � ���N�N!�pRv] � ��� g ����� [��������N U �>[,R U �>$7� K $ � ����hFnrN# ���m � �,���)����3k$7N!���)�>$7����N!���pR��� �� U ��fR������ � ����N#�6R( � � �6R�N#� + �H� � "HX W#W� YJ^ % ���C�%RwnrN# J$7�f[x��NI� � � �C[N'a�����]�n � �� ���h g ������0���6R*�� ���,�����JRR�6$J] � R � � � � �6[ � � � "a�����] � ���5��])���� � �������6[ � �� � R�R*�� U ����N!�\R � �6[,�����,��� � ����N!�\R ( [�%R*q$76R�R*�>[ ��� � ] � U ���/ � YJ^ Y_�F�pR&��N g ��]�N U �f[ ��] � �F��� ��])�Inr���� ��'�,N! �� R�N U ]��%R*���p$ � ���>[ "��N!��qr������� � A��N�N#�%RAa������ g ��[���������N U �>[x��] � �k$ � � g �,6R*�>[E��N'��]� �NZaP�,N# ��"����3!]��AN#� ])NZa�������� �� � �� �� U ��fR������ � ����N#�6R � ���N# �3 � �����/�>[ " � �6[ �,N! �� ��� U N! �� � �����h'"-]�N>a���]���h ��e ��e � o��[� �����3��� � ��������3�^ ����] ��]��C��N�N#�%R � � � ��� �>g ���C��N'�,�hY�a � RTN#����h �>g ���C��N'���>R*� � R���� U ���]h U N!��])�>R��pR ( � ^ ��^ "�a�]�����])�� i ���3!)� � uR � �\[&��m)$7� U ����N#�6R5aH�/ ��H �� U ��>R��������f[A[� '5�/ ���������h+���.��]��]��%[�[����,�������R U � $7�#Y%" g ���a � RH��N!� �>g ���+��NC[�%R�$7N>���� � ��h,����a(N# �3 � ��� � � ����N!� � � U ����6$7� U ���fRg �/h�N!�6[,��] � ��^ �H]��0��N�N#�%RB$c])N�R��/�Iae�� �� � [� �� � ���wnrN# ����>R�������3"��]��%RH�����,�����>[A]�h U N#��]��fR��%RS^

V����� ��C���f$c]��)������>R��,��3#]� g � �Zg ���F��N ������ � �-�,N# �� �Zg N#��"��]��")�6[�� ���h�����3 N! �3 � ����q� � ����N!� NZnO��]��,])�%[�[�/�b��)���"R U � $S�'"-a�]��� �� � R0a�����]���]��F���6R��� ���D����uR � � � ��� �>g ���C��N��D�hYa � R-N#����h �>g ���B��N � R�$7�� �� � ���Fa�])����]��/ jN# 1��N!�e ���3#�� � JR � �6[C��m�$S� U ����N!�6R�aH�� ��� �� U ��>R��/����>[R�� U � � ������h'" g ��B��N!� ��o��xN! � � �>^ �H])�A���f$c]��)������>RHYHa � RHnrN! u$7�>[I��NF\R��A])�� �� ( g �>$ � 6R��NZn���])���� � � � ��� �Zg ��������h " � �6[C�Fh.NZa�� � � $ � NZnWR�� � ���%R����%$ � �KR�N U ]��%R*���%$ � ����N!�,��N"[�/��pR��B� � ����N# ��>[���>$J]���� �2��fRcY0� � hE] � ���'N!����h ���tnr���>[ ��]�� � ��� U NZn.��])�Q$7� �� � ��� � N#�(��]�� U ����6$7� U ���>RA��] � ���6[�� ������+��]��OK6� � �4N! �3 � ����� � ����N!��N>n1��])�T])�%[�[�/�I)�����BR U � $7�V^

Page 165: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X ��� ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

��� � � � ��� � ������

�H]��"3!N � �HN>ne��]��C ��>R*� � u$c]' �� U N# ����f[x������]��pRw��]��>R*�%R�a � R+��N ��fR�N!����� � �b��� U N! �� � ���+$SN!��q�� � [�%$S����N#��������]��"�������� � ��) ��AN#� �� � R��� ���3!)� � O� � U�U ����3VR�g+$SN!�����f$7����N!���pR��+���/��aeN! � R � ��3!�����/ � ����h � R�R�)�,�>[ap�o��H��N $7N!��� � ��� � nr��6$7����N#� � � [ � �e �N#����'" g �� U N>aH�� *nr��H�/��p[���6$7�] � RB$7N!�D����NF����3!]��Hnr �N#�����fR���N#�����)3CR���\[���>RHa�])�%$J] R��3#3!�>R*�JR���] � ����]���h [�N�^

V�N# H��])�A[�� g6� ��� g ���*aH���/�,$7N#�����>$S����N#���%R*� � �6[ [ � �K �N#���� � $/$7N!����JR1��N U �N!3# ��>R�R#"���])�%R$7N!���� � [�p$7����N!�������f[�R+��N g �F ��>R�N#�����>[ (KN!��])�� �a��pR��D[N! g �JR+aHN#��%[�������3!�� �Zg N!��.a�]�����]��� ��]����*aHN � U�U �N � $J]��>R � ������"�>R�R*���6$7�B[�� 'K�� ��/�� "!N! 1a�]�����]��� 1��])��h � ��'"����An � $7� "���� U ���/�F���)q� � ����N#� � �4� � �� � ��uRvN>n-��]��.R � �D�wnr)�6$7����N!� � � � u$c]������>$S��� ���^

�H])�"aHN! � �� U N! ����>[����'��]��pR���])�>R��pRv�pR���]����6 JR*�0R��/ ���N#6R � �����/� U �B��N,������>R*����3 � ���0��]��U ��>R*���6$7�0N>n � nr)�6$7����N!� � ��[ � �i �N!����T��� � $7N!�)���>$7����N!�)�%R����)���*aHN! � ^ �OR U � ��BNZn1��]��%R � ��q����� U � "�[��� � �����>[C$7N!�6R*�%[�/ � ����N#�6Rvae�� ��O �� U N! ����>[,N#�I��]��+� � ��� ��0NZn ��m�$S� U ����N!�6R "��]�� U NVR�qR�� g �������\$ � �� � ����N!�\RWN>n � [ � �6 �N!�������� � $SN!�����f$7����N!���pR��1�����*aHN# � " � �\[&��'K�>$S�������e�,����]�N�[�RnrN! �[������>$S�����)3+��]��/��^��+R-ae����� " � $7 ������%$ � � � U�U � �pR � �5a � RH� � [���NZn���])�����>R���N!������30�,����])N�[qN!��N#3!h 6R*�>[,N!��$SN!�����f$7����N!���pR��H�DN�[���%RS^

])����� ��]��1� � $ � NZn\R�\$�$7�>R�R5�����6�\[����3 � [ � �� �N#����e[N��>R4��N#�)( � �\[A$ � ����N!�SY U �N>���-��] � ���N $7N#�����>$7����N#���%R*�������*aHN# � e���e�dB$7N!�\R��� �6$7�uR � nr)�6$7����N!� � �-[� � �- �N!����'"6���O[N��>R+R*�� �N#��3!��hR� U�U N# ��0��]�� (r]�����]��� ���N R*��� U ��h � R�R*��,�>[ Y � R�R*�� �����N#����] � � � [ � � �N!)���"�%RB��N!�bd0e���� ��d�e����NA��� U �����F�/��� �� � R*�� ���3!�� � 1� � U�U ���)3�R#" � �6[F��] � ��$SN!�����f$7����N!���pR��1�����*aHN# � R-��]��� ��7nrN! �� ��o$7N!�6R*���������� � ��� �>g ���.$7N#� U �� � ����N!� � � � ������ �� � �������+��NC��]��.[ � �4 �N#���� U � � [��3#��^

�(�,N# ��O$7N!�6$S��6R*������ ��fR�����ja������6��N#� g � U N�R�R�� g ���B������� � nr)�����/ j)�6[�� uR�� � �6[����3AN>n���]���������� �� � �1nr��6$7����N!� � �BR��� �6$S��� ��IN>n0$SN!�����f$7����N!���pR��"�����*aeN! � RA�%R � $c])�������>[K^ �BNZae������ "-��NR��� �����3#��]����'��]��k$7N!�)���>$7����N!�)�%R�� � $/$7N!����BNZn��� � R*�� ���3!�� � +� � U�U ����3�R "����B�%R���N>a ��]��.� � R �NZne$7N#�����>$S����N#���%R*���,N�[�������� uRj��N,[�/������N UIU � � \R�� g ���bc�� �Je�d�p�c�� ����eB��m U � � � � ����N#�6RvN>n1]�N>a � ���U � ������ ��6R � � U)U � �����B ��/3!�� � JR � �6[I�/m�$7� U ����N!�6R � $ � � g �T� � U�U �>[ g h,��]��.N!���0��)�tnrN! ���,�>$J] � ���pR���^ �H]��������� � �������1��m U � � � � ����N!� U �N U NVR��>[ g h �-� � )� � �6[ ��$ � ������� � �6[ (�X W�W!` Y ���] � � � $7N#� U N!���/���� � �� �� U ��>R*����� � ����N#�"�%R-[�/������N U �f[A���"��])��]��p[�[���")�����1R U � $S����NT�/�6$7N�[� ���3#�� � � �6[ ��m�$S� U ����N!�,aeN! u[�R � �%R � R*��� U ���,��]��0 ���3!]��B[�� ��>$7����N!���S^

�� &8�C9 )��;��5�!���$(���7/����9���� �H��(�)>%A�C� �C(�9�I2)*��)* ��!����( ������9�� �6���5�$(���7/�4G 9�;<)>=���� =#%4)B(��!����9�� (�&�) (� ��!��������I6;��$( G(�)* ��89 J')* �)H=D7 % )>% ��� (�)* �H9#7!?:(�&� �)*)H).�!9������2G 9�)*;��$ ����8�C)H=D7��H;<7/�8)*�4(�9 + 72��9�)*(����/)* ����!��% =D7 %8�/1�� (�� �4�C�8I

Page 166: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��4����� �e���� �4���+� � � �1���4������������� � � ���T� � � �H��� � ��� X � `

% �6$S�T��]�� �>g �������*hCNZne$7N#�����>$S����N#���%R*�BR�h)R������ Rj��NF��� U �����,�S����� � R*�� ��/3!�� � �� � U�U ���)3�R�%R+��6[�/ JR���N�N�[ "1]h U N!��])�>R��>R0$ � � g �,3!�/���� � ���>[���N'���>R*�0��]�� U R�h)$c]�N#��N#3!�%$ � � ����>R*����N#�ENZn�������� ��>R��ia�]��p$c],N>n1��])�+�*aHNCR��� � ����3#���>R��%RH6R*�>[ g hC]��� � �\RH��N"��� U �����C����� �� � R*�� ��/3!�� � $7N!3#�����������+� � U�U ����3�R%$ � n � $7�/��NZn ��]��pR��2��fR�����N!� �%R�[��%R�$S6R�R*�>[I���I��]��0����m���R*�>$7����N!�4^

����� �� ��� � � ��� � � � � � � � � ������� � �� � �) � � � ���

�H]��A ��>R�� � J$J] �� U N! ����>[ ��� ��])�%R���]��>R*�%R�] � RHnrN�$76R*�>[�R�N#������h,N!�'��]�� ����>R*����N#��N>n1a�]�����]��� ������������ ������� � ����� � � ���!���"� ��"� � � ����� C$7N!�\R��� �6$7� � [ � �� �N!)��� � u$c]������>$S��� ��F��N���� U ����q�,����� �� � R��� ���3!)� � "� � U�U ����3�RS^$# � ��]��pR"R��>$7����N#� "%#A[�pR�$7\R�RT])NZa ��]�� U ��>R*������6�6[����3�R�,��3#]����� U � $S��N#�b��]���"�� � �&���'�� � � ��� �2��fR�����N!��N>n��������/ ��>R*� � ��] � �0�pR#"5a�]��/��]��� � � (���

6R��C[ � �1 �N#����"nr��6$7����N#� � � � J$J]������>$7��� ��>R���N ��� U ���/�,�7��� �� � R*�� ��/3!�� � 0$7N#3!�����������"� � U qU ����3VR7^ �H])�%R [�%R�$76R�R���N#�(] � R g ����� [��� � h��>[ �����������]�� � N!�\$7��6R*��N#�6R $c] � U ���/ � R,���D�%RR��� ��%$7����h g ��h�N!�6[ ��]��.R�$7N U �AN>n1��])�%RH��])�>R��pR#" g ��B�����pRHNZne$SN!� uR�� �$�)�e��6[�/ ���h����)3 �2��fR�����N!���] � �+�����\[�R���])�"$7� � ������B ��>R*� � u$c]'�,N�R*��N>n����uRv������� ��fR���^ �H]��AnrN!����N>a����)3,[�pR�$7\R�R���N!� � �%R�NU ��>R*�����JR � � � ��) � �)N U�U N! �����)���*h"��N0R*�3!3#�>R��eR*N!�,�1nr���� ��HaeN! � ���"��]��%R � �� � "!��] � �1aHN#��%[���>R*����]��0a��%[��� � U�U ���%$ �Zg �������*h"N>n-��]�� �6�6[����3�R� �� U N# ����f[I]��� ���^

#*R4��� U N�R�R�� g ���e��NO[ � a $7N!�\$7��6R*��N#�6R �Zg N!)�ja�])����]��/ 4]�� � �6R5��� U ���/�F����� � [� � �� �N#����nr �N!�G��]��O$7� � ������ �6�6[����3�R%$ � N!�e[�� ��>$S����h � $7N!���)�>$7����N!���pR��1�����*aeN! � R � ��'"�NZn�$SN!� uR��'"���m�q�� ��/�,����hOR���� U ��� �6�>[��,N�[�/�%R4NZnK��]��e])� � �.$7N#3!�����������eR*h�R*����� " � �\[A ��>R*����uR;N>n4R*���C�� � ����N!�6Ra�����]&" � �6[ � � � ��h)R��>R+NZn "4��]��>R��CR*h�R*����� R+$ � �)��N!� g �,R*�� � ��3#]�*nrN! �a � u[��h��/m�� � U N#� � ���>[���N]�� � ��$7N#3!��������N!�4^ � � ��]��/ "1������]��pRA��]��fR��%R(#0] � ��� g �/��� � [��N�$ � ������3b��]�� ��$ � ��NVR � ��h(�X+*,*X>Y+nr � �D��aHN# � NZnB�� �� � ������3�$7N#�����>$S����N#���%R*�0�����*aHN# � R � R-���"�� (���� (� �.� � 0NZnB]��� � �$7N!3#��������N!�o^/#_�Q��]��pRwnr � �,��aeN! � "�$7N!�)���>$7����N!�)�%R��0�,N�[����%R � �� R*����� � RAR*��� U ��� � � � ��N#3!��>RNZn���])�T]��� � �,$SN!3!�)���������+R*h�R*�����P��] � �H�D��3!]��e[� 'K�� e���,��]����� H��� U �����C����� � ����N!� � �6[ $7N!�,qU ����m����*h'" g )��] � ��� � ����� � � �������������0�1� e���'$7N#�,�,N!�Ca�����]���]��0]�� � �'R�h)R�������( ��$ � ��N�R � ��h'"X+*2*�XZYu^ �H�>$ � \R�� � �)��� � �-�,N�[���pR � ��C�,N! �� � �,�/� �Zg ���"��N � � � ��h)R��pR � �6[b� � ��� U �� � ����N!� "��]���h'$ � � g �"6R*�>[���ND���6$7 �� � R*�A��\[�� JR*� � �6[���)3IN>n���]�� � $7�� � � "5�DN! ��k$7N!� U ����m-"6R�h)R������ "�2%��/�!�4(��!I/) 7!? (�&�)#? �/=�(:(�&��!(:�!���MJ'7/ �% 9:�C��(�&�)#(� ��$��������I 9�)*(�J')* �) �H72��7/9�� ���5���8�"= +43 ��%4 �)*J:9�� ,>-2- �41*L

Page 167: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

� �6[ ��N"3!�/���� � ���0]���6$J]��>R � �\[I]�h U N!��]��>R*�>RjnrN! �nr� ���]��� ����>R�������3)^�H])�T� � �*N! e���6R*��3!]��H3 � �����>[Fnr �N#����]��pRHaHN# � �pRH��] � �B$7N!���)�>$7����N!���pR��e�����*aHN# � R � U�U � �q

�������hk[N-�����K�����>["��N.���6$7N�[� � ��/3!�� � �qr��m)$7� U ����N#�C[�%R*�����\$7����N!�C��NA��� U �����,�S�� �2 � R��� ���3#q�� � �� � U�U ����3�RS^ ������]�N!)3!]��)���*aHN! � � � U�U ���)3�RB$ � � g � �.� � ��� # ���T���'���� �� RjN>ne ���3#�� � JR

� �6[ ��m�$S� U ����N!�6R " � �6[�[N! g ���.[�pR�R�N�$S� � ����N#�6R g ���*aH���/�,��]��fR��A�*aeNC$ � ����3!N# ����fRvN>n U � ������ ��6R] � ��� g ����� ��>$SN! J[��>[,��� ��]��.$7N#�����>$S����N#���%R*���������� � ��) ��'"��Ch � � � ��h)R��>R�NZn ��]��0]��p[�[��� ��)��� �� U ��>R��/�� � ����N!�6R1[�/�,N!�6R*�� � ���f[A��] � ��R�\$c] � [�pR������6$7����N#�"a � R1��N!� � � U R�h)$c])N!��N#3!�p$ � �� �� � ��q���*h � ( � N!����]�� � �� " �H�>R*���� "��!N#� � R�R�N#� " + � � ����� �!� "6X+* *2Ye���C��])��nr��6$7����N#� � � � J$J]������>$7��� ��NZn ��]��0��m � �,�����>[F�)���*aHN! � RS^yV���,��� � ���h'"#]�� � � �� � R*�� ���3!�� � B� � U)U ����3VR (_R*6$c] � R U �N!��N#��6$7����3 �W�)3!���pR�] ���/m� "�N!

U � R*��qr�����6R*�+��� �6�>$7����N!�KY-] � ��� g �/��� [�>R�$7 �� g �>[&���,���/ �� RiN>n- ���3!)� � uR � �6[F��m)$7� U ����N#�6R#" � �\[[N! g ��� [�pR�R*N�$7� � ����N#�6R g �/��ae�����E��]��>R*�,�*aHNQ$ � ����3#N! ����>RT] � ��� � �%R*N g ���/�E ��>$SN! J[��>[5^ �H���%R���]��. ���3#�� � �qr��m�$S� U ����N!�'[�pR������6$7����N!� � U R*h�$J]�N!��N!3#�%$ � �4 �� � �����*h,������]��A]��� � ��$SN!3!�)���������R�h)R����/� $

#_�.�%R U ��>R*�������h���N#� U N�R�R*� g ��� ��N � �\R�aH�/ "��]��pR ����>R�����N#�E��� � [�� �6�����������DR��/�6R�� (r�_^ ��^ "���0�%R+��N#�Ah���� U NVR�R�� g ���D��N��/m � �,�����.�������� �� � � �� U ��>R��/�� � ����N!�6R0���Q��]��C]��� � �Q$SN!3!�)���������R�h)R����/��YJ^ ��N>aH�����/ " g\� R��f[�N!����])�TaeN! � �� U N! ����>[�]��/ ��'")# � � N>n1��])�AN U ������N!����] � �B��]��R�� � �6[ � J[� ���3#�� � �qr��m�$S� U ����N!� [�%R*�����\$7����N!� ( � Rw)�����������f[ "2nrN# +��m � � U ���'"������]��k[ � �- �N#������������ � ��� ��!Y-�pR�R����,��� � ���h ����� � �� � ������hC��� ��]��0]�� � �'$7N!3#�����������0R*h�R*����� ^��+R*����3"���6R���3!]��JRnr �N!�P��])�%RHR*��6[�h'"�#-a������6N�'K�� BR�N#�,�OR� U�U N# �������3C����p[���6$S�HnrN! ���])�%RjN U ���)��N!�&" � �\[IR*�3!3#�>R��nr���� ��0aHN! � ��NC���fR�����])�%RH]�h U N!��]��>R*�%R7^

��������� ��� ����& �"#� �� � ����������� �

� g N�[hENZnO��� U �� ��p$ � �������%[�/�6$7�'"���] � �"�%RTN>nr����� � [�[\$7�>[ g h [ � �H �N!����%R��uRA��NQ[�/�,N!��qR��� � ���"��]�� U R�h)$J]�N!��N!3!�p$ � �� �� � �����*hIN>n���]��" ���3#�� � �qr��m)$7� U ����N!�Q[��%R������6$S����N#� "5�pR���] � �0a�]��%$J][���,N#�6R��� � ���>R � ��� ����� ��������� ����� � �r^ �v��3#�� � �����h"��'5�f$7�JR � ��0R � �%[,��N"N�$�$7� �� n g �/] � ���N!� � ��,� � R*� ��fR+$ � � g � R�]�N>a��E��N�R�h)R������ � ���%$ � ����h'[� 'K�� .a�]���� R� g �*�>$S�JR U �N�$7�>R�RT ���3!�� � .N! ��m�$S� U ����N!�,aeN! u[�R�(���] � �B�%R "��tn���m)$7� U ����N#�6R � ��T�� �� � ���>[ [� 'K�� ���������h�^��������� � ���5 ��fR�����JR5nr �N!� ��]��e[ � � �N!����H�������/ � ��� �� ���6$7��6[�-��]�� �6�6[����3B��] � �i��m)$7� U ����N#�aHN! u[�R � ��� �� � [(R���N>aH�� C��] � � ���3!)� � uR (�� � �N#� + y��� � aBR�N#� "AX* � � Y (0��] � �,��m)$7� U ����N#�

Page 168: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��4����� �e���� �4���+� � � �1���4������������� � � ���T� � � �H��� � ��� X � �

aHN! u[�R � ���] � J[��� F��NE ��f$7N!3#������� � R"aHN# J[�R (�� � ����� "+X* ��� Y ( � �6[ ��]�� �Zg ��������h ��NE �� � [( N! C3!�/���� � ��� U � R*�,�����\R��>RTnrN# 7Y" ���3!�� � uR � �6[ ��m)$7� U ����N#�6R"$ � � g � � 'K�>$7���>[�[� 'K�� ���������hg h'���>R*��N!�\RwN# 0����� �N!��N#3!�p$ � � U � ��]�N#��N!3#h ( � � JR�] � ��� + � ��a�$7N#� g �'"�X+*�� ` (��W�������� "-X+*,*X�(y�] � �����p$7�+��� � �_^ "KX+* � ` Yu^

�H])� R*� � �6[ � u[ $7N#�����>$S����N#���%R*� ��>R U N#�6R�� ��N(��]��%R g N�[�h N>n,�/��p[���6$7�Q] � R g �/��� ��N�� �h � �6[ �1� � ��� � ��� �BR*6$c]� ���3!)� � ����*h,��'K�>$S�JR�����$7N#�����>$7����N#���%R*�����/��aeN! ���R���] � �+��� U �����D�7���

� R��� ���3#�� � j� � U�U ����3�R (r��^ 3)^ "!��]��+� � ���N!\RW�)���*aHN! ��"���>R*��N#������3.R*��6[���>R1$7�����>["����1] � U ���� � ( � �\[ � ������� U �JR1��NCR����F)� � ��� U �N!����6$S� � ����N#��� � �����\$7���>R � �6[ nr �� )���6$7hC��'K�>$7�uR�( yV���%[�/��q

g �/ �3 + ��$�1������� � �\[ "6X+* � *2Y " ��NC[���,N#�6R��� � ���+��] � ����])�>R��+��'5�f$7�JR�$ � �,N�$�$7) �a�����])N!�� � ���m U ���%$S���1 ���3#�� � �qr��m)$7� U ����N!� [�%R*�����\$7����N!� g ������3"���6$7N�[��>[,��� � �����*aHN# �K^��H]��>R*� � ������� U �uR] � �����,��� "HR*NEn � "�a�����](N!�)��h �����,�����>[ R�6$�$S�>R�R nrN# ��m � � U ���'"H$SN!�����f$7����N!���pR��C�,N�[���pR��] � ����� U �����C����� �� � ���pR����%$+$7N#3!������������� � R��)R�R�\$c] � RH �� � [�����3 � ��N!\[ N# ���]��03#������ � ����N!� NZn�W�)3!���pR�] U � R��B�����6R*�>R � ��Ah����e��N U �N�[�6$7� � [�N! g ���.[�%R�R�N�$7� � ����N!�'N!� ��]��0N#���A� � R��K^

� � R��>[EN#� ��])�I���6R���3!]��JRA3 � ���)�>[bnr �N!� ��]�� aHN# ����� ��]��pR&��]��>R��pR#"-]�N>ae������ "%#0aHN#��%[R��3#3!�>R*� � [� 'K�� ����� � � ��3#����N>n � ��� � $�����nrN! � [��N�$ � ���>RiN>no$7N!���)�>$7����N!���pR���^ � R #5] � ���1nrN!��\[���,��]��%RH��]��>R��pR#"����H] � R U �NZ���f[F���� �hD[��� $7)���1��N"N U �/ � ����N#� � ������� � �����fR�� � �6[ � ��m�$S� U ����N!�6R�� "�������Qa�����])���E��]�� $7N#�����m�0N>n+��]�� R�� � ��� � �6[E ��/� � ����������h�ae������q_$7�� J$7)�,R�$7 �� g �f[I� � U�U ���)3�R��h U �p$ � ����h ��� � ����f[ g hQ$7N!�)���>$7����N!�)�%R��.R*h�R*����� RS^��\) ���])�� ��,N# ��'" � RT�)N!���f[b����1] � U ���� � "��]��0� � ���%[����hDNZn � �h,�/m U �� ����,����� � �6����p[���6$S��nrN! B��]�� ( ��N#�5Y_�/m�pR����/�6$7�+N>n � [� � �� �N#����.�%R� � ����� ����� � ������� � ��� ���FN#� ��]�� $J]�N!�p$7�CNZn � $7N! � ��>$7�.N U �� � ����N!� � ��� � � ����N!�EnrN# " ���3#�� � JR � �\[��m�$S� U ����N!�6RS^

�H])�BR � �D�H�,����]�N�[N#��N!3#�%$ � ��$SN!�6R*�� � �����JRiaeN!��p[ � �%R*N � U�U ��h'"!N>no$7N!� uR��'"���N+��m U �/ ����D����q� � � � � � � �&��� ����� � ���KR���6[���>R���] � �0] � ��� ( U � U N# ����f[��h6YB�>R�� �Zg ���%R�])�>[���]��" ���3!)� � ����*h ��'K�>$7�/^��N>a $7 ��f[� g ��� � ��A��]��0N U �� � ����N!� � ����� � ����N!�6RBNZn1��m)$7� U ����N#�6RH��� ��]�N�R*�CR���\[���>R%$ # n ���BaH�� ��nrN!��6[Q��] � �"���6$7N# � ��>$7� ( N# � �"��� � R*� " U N�N# ���h �*6R���� �6�f[ YBN U �� � ����N!� � ����� � ����N!�6RAae�� ��C6R*�>[ "��]��pR"[� �K$7�����6$7hQaHN#��%[�$ � ���������N ��fR�����N!����])�I� � ���%[����*hbN>n0��])�I ���3!)� � ����*hE��'K�>$S� " � �\[]����6$7� ��\[�� ��D�����,�C6$J]�NZn0��]���R* U�U N! ������)3 �/��p[���6$7�CnrN! C��]�� [ � �O �N!)������]���N# �h����]�� � �6RS^

% ��� � ��������TnrN# wnr)��� ��FaeN! ��aeN!��p[ g �F��N�$7N#� U ��/]����6R*������� h, ��������a ��]��" � ��3#�,NZnN U �� � ����N!� � ����� � ����N!�6R+��] � �0aH�/ ��A\R��>[����'��]�� U R�h)$J]�N!��N!3!�p$ � ���������� � ��� ��.��N �>R�� �Zg ���%R*]���]��

Page 169: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

���3#�� � ����*hC��'K�>$7�/^� R � � ��������� � �1R���� U ���b��]��%R.[�� ��>$7����N!� " #�] � ���D$ � � ����>[�N!�� � U � ���� � �e ���������a N>nB��]��

�������� � ��� ��"[�/��N!���f[���N,��]��"�*aHN � R��� ���3#�� � +� � R��)R0[�%R�$76R�R*�>[ � �0������3!��]�������]��%R���]��>R*�%R� 3#������ � ������3 �-��3#���pR�] U � R*�T�����6R*�AnrN! �� R#" � �6[x �� � [�����3 �-��3!���%R*]�����m��+N!)�T��N!6[K^ ]������$7N>���� �����3,N!�)��h � �����,�����>[, � ��3!�,N>nB��]��D�������� � ��� ��'"5���A[����,N!�\R��� � ���>R+��] � �A�������Q���Q��])�%RR�� � ���6R � � U ���'"!��]��+N U �� � ����N!� � ��� � � ����N#�6RjN>n� ���3#�� � JR � �6[F��m)$7� U ����N#�6R-� � �hD$7N#�6R��p[�� �>g ��hV^

��������� � � &$#�� � �� � ��� � � � � �

# � ��]��'$ � R��,N>n �-��3#���%R*] U � R*�"�����6R*�>R#"-��]��� ��,aHN#��%[ � U)U � � "��N g � �����������D[�%R � 3! ������,�/�����(��])�b��� U �� ��%$ � � � �\[ �,N�[����������3b�������� � ��� ���N!� a�]��p$c](aeN! J[)RI$SN!�6R*����������Q��])�QR���� NZn��m�$S� U ����N!�6RS^��H]��0N>���� �a�]������D����30 ��/3!�� � ����*hF���I��]��+� � U�U ����3"NZn �-��3!���%R�]'���� g R ( * ��� NZnU � R*�H���/�6R��>R1$ � � g �+$SN!�6R*�� �\$7���>[ g h � U�U ���6[�����3 � [���(��� � �6$7�pR)+��+�$S�� � " X* � � YeR�)3!3!�fR��JR��] � �I]��� � �6R ( � �6[ "+���6[���f[ " � ��h( ������q ��� � ������)3E�,�>$J] � �)�%R��'Y+aHN#��%[ ��%$����h����6[\$7���]���N g ����N#6RF �)���'" � �\[M�� �� � � � �h aHN# J[�R,��N#�I] � �6[���>[ g h ��] � � ����� � R �/m�$7� U ����N!�6RS^�H]��F���/ g <� ��� q <� ��� =�� aeN!��p[x��]��� ��7nrN! �� g �C ���3#�� � " � �6[ =�< q <f= ��m�$S� U ����N!� � �_^ �H]���Zg N>���T�pRH��]�� U NVR�������N#� � [N U ���>[ � R � � � ������ 1NZne$SN!� uR��0���, ��>R�� � J$J]'R�6$J] � R��Hh g ��� � �\[y���N g ��� (�X+* ��� Y " � � )3!]��� ��*h � �6[�y��/�%[��� g �� �3 (�X*2* � Y%" �-��� ���� (�X+*,*X>Y%" � �6[ �-���� ������� � �\[� � J$J]�� � � (�X*2* � YJ^

�H])�� �� � �� "v])NZae������ "j�*aHNQN g ����N!\R U �N g ����� RAa�����](��])�%R � R�R*�� U ����N#�4^ �i�� uR�����h'"1���R�]�N#��%[ g �B��N!���>[A��] � �1��]��1nr �� ����6$ShTN>n � ��/3!�� � �#���� g R �N!���>[ �Zg N>�����%R;nrN# 1���� g � ��� � � ^# neN#���,��N�N ��R � �A��])�Anr �� ����6$S���>R�N>n����� g � � � � � �����-��3!���%R*]E$7N#�,�C����%$ � ����N!� ( ��] � �.�%R "��]�� � $7�� � �e6R � 3!�'R�� � ���%R����%$�R+nrN! .���6[����p[ � �-���� g RcY%"���]�� [N!�,��� � �\$7�"NZnB��]��>R��D ���3#�� � JR[�%R � U�U � � JR#( �Hh g ��� +(y���N g ��� "�X* � � YJ^���n)��]�� `� �,NVR��6nr �� ���������h�N�$�$7� � ����)3����� g ��N �����6R "��� � �� � ��m�$S� U ����N!�6R���^���n)��]�� ��� �,N�R*�5nr �� ������5���� g R#" `� � ��H��m)$7� U ����N#� � � ^ � �6[+���0h�N#���3$c]����%[ ���� � RjR U ���>$J] "�a�]��� �� U ��>R�)� �Zg ��h"�,N�R*�H��� � �������3.� � ���>R U � � $7� " � �/m�$7� U ����N!� � � ������ g RU ��>[�N!�,��� � ��� ( �Hh g ��� +sy���N g ���&"X* ��� YJ^ #_�i�pR;��]��� ��SnrN! �� � �"N U �/� ��fR�����N!� � Ri��N+a�]�����]��� ��]��.��m U �>$S���>[ � � [�[,q_[ � �����.�%R � ��a � h)Rv���6[6$7�f[ " 3#�������'R*6$c] $7N!�\R��%R*��������� � ���h ��m U N�R*� ����N"���� g RH��] � �+[�NF��N#�B$7N!��nrN! �� ��N"����^yV�>$7N!�\[��h'"���]��/ ��+�pRHR�N#�,�0[�pR � 3! ��/���,�����1���,��]�� U � R*��qr�����6R*�0�������� � ��� �� � RH��N"a�]�����]���

� ��� � ��m)$7� U ����N!� �i���� g R � �����m)$7� U ����N#� � ����Nb��]���R � �,�'[��3# ����V^ � � ����� � ����������h [� 'K�� �q

Page 170: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��4����� �e���� �4���+� � � �1���4������������� � � ���T� � � �H��� � ��� X � �

����O��h U �FN>n� ���3!�� � ����*h�$ � � g �D[�����>$7���f[������� � �6R_nrN! �� � ����N!�\RTR*6$J] � R �� ��� q � ��� � �\[? ��� q ?� ��� � ��� � [���)3(R�N#�,� � ���]�N! uRI��N R��3#3!�>R*����] � � � �s��m U � �6[��>[sR��/��NZnC �����fR g �

� [N U ���>[���ND] � �6[����"��])�>R�� � R�aH����� ( � � ����� + ��N#] � � � � "1X+* � � (��5����3 "1X+*2* � g Yu^(#_��N!��]��� aHN! u[�R#"e��]��� ����pRF[�pR � 3! ��/���,�����AN>���� "a�]��p$c]����� g R � ��'��m)$7� U ����N!� � � " g �>$ � 6R*����]��� �� �%R[�%R � 3! ������,�/��1N>���� H��]��.R U �>$7� �K$0R�����N>n1 �)���>RH��] � ��]��� � �6RH���6[�6$7��^

��������� � � ��! ����� ���!& � �!& #�� � � ��� �

�H]���N U ������N!�6R"��� U � R���q �����6R��� ��>R�� � J$J] � ��� ��/� � ����������h�]�N!�DN!3!�/����N!\R � �6[($7N!������ �3!����� "$7N!� U � ��f[x��N���])�F��m��� � N# J[��� � �����h�a��p[�, � ��3#�,NZnBN U �/ � ����N#� � ����� � ����N#�6RTnrN! .��m)$7� U ����N!�\R��] � ��ae�� ��+�/�6$7N!)����� ��>[C��� � R*]�N! ����/m � �,��� � ����N!�,N>n-��]�� �W�)3!���pR�]'����m���qr��N#q_R U �/�>$c] �������/ � q��� ���^

� RH��N!���>[,��� 1] � U ���� � "�N!���0 �� ��� ��>R � $SN! � ��>$7�e� � U�U ����3 � �6[ � � � $7�� � �4� � U�U ���)3��N'[� �6�)�"��m�$S� U ����N!�6RS^�H]��D$7N! � ��>$S�+� � U)U ����3 "5������]��D$ � R*�FN>n �-��3!���%R*] U �N#���\$7� � ����N#� "�%RF��N#�, �� � ����h���� $7N#����������N#�����F�pR,$7N�[� �6�>[ ��� [��%$7����N!� � ����>R ( � ����]�N#�3!] ��])�>R��'" � 3 � ��� "[���K�� 1R*����3!]�����h0nr �N#�G$7N#���� �h.��N.$7N!)��� �h'" � $/$7N! u[����30��NA[�� � ���>$7�SYJ^ #_�-�%Ri��]��O[�%R � 3! ������,�/��NZ���/ "��]�� �� ����0���-� � U�U ���)3 ( N! D��]�� R����CNZn U �N!����6$S� � ����N#� �)���>R"��] � �F]��� � �6R"���6[\$7�nr �N!�G�/m U �� ������6$S�!Y5��] � �e$ � 6R��fRj[��%R�R*���6R*��N!�CN!�D��]��B$7N# � ��>$7�1$7� � R�R�� � $ � ����N!�CNZno ���3#�� � JR � �\[��m�$S� U ����N!�6RS^

�H])���������� � ��� ��1N!� �-��3!���%R*]" �� � [����3 � U�U � � JR-��N g �eN! �3 � ��� ���>[A�����N+�*aHNB� � ���AR�$c])N�N!�%RNZnK��]�N#�3!]���^�#_�A��])� �6 uR�� " � R�����NZn ��� �4� � �%R � R�R*��,�>[0��N+�/m�pR�� ">��] � � [�%R*�����)3!��pR�]��>R� ���3#�� � JR� �6[b�/m�$7� U ����N!�6R0N!�E��]�� g6� R��%R0NZnOa�]�����]��� "R*6$J]baeN! J[)R � ��D] � �6[����>[E$SN! � ��>$7����h g h���]�� �����>R7^0y�6$J]� �����>R � ��"6R* � ����h'$7N#�6$7�������>[,NZn � R���� � ���)��� � �����&��� ��� ���%��� ��� � �&�����.� �� ������ � � ( [�%R�$76R�R��>[,��� 1] � U ���/ � Y�6��] � ���%R "���]��/h,� � U $7��6R*���� uRHNZn ���������� uRj��N U ])N!�����D�>R7^

� U �� � ����N!� � ��� ������3"��]��.[�%R*�����6$7����N!� g ���*aH���/�I ���3!)� � uR � �6[ ��m)$7� U ����N!�\RH �� ��� ��>Rj��] � ���]��pR�R�����N>n � � �����>R g �"R U �>$S� �6�>[K^ � NCR�6$J]'R����BNZn �)���>RH] � [ g ����� [��������N U �>[F��� ��]��� � ���h"X* � � � R "!a�]����0�������/ ��>R*�4���0��]��e[ � �� �N!)���1��]��/N! �hwR�� � ����>[T��N�3# �N>a "!R*N U R*h�$J]�N!��N!3#�%$ � � ��>R*� � u$c]��/ JR+a�]�N��)���>[�>[ � �� � R*N!� �>g ���DN U �� � ����N!� � ����� � ����N!�Q��� ����>[b��N���]��,$SN!�����������/��R����uRWN>n����!� ��� � � ���! H �����>R-[�/������N U �f[ g h��H�� u[� � �6R���h'" 1 �N!���)����� " � �6[ �wN��/]����� (�X+* � *"6$7�����>[��� � � JR*] � ��� � �6[ � ��a $7N!� g �'"�X+*�� ` Y " 1]�N#� R���h � �6[ � � ����� (�X+* �$# Y%"�� � ��� � " � � ��� � "

�&% �<%4)*)>% �8(�&�)B9�)#? 72 ��A9 �$ �)E=��5�!9�9�)>%F�$9: �)*I2���5�! :���(')+*-, ��I/����9�& +/. �! �)102, � � �$� �!����;� �)B9�9�1BL

Page 171: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � # ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

��N�[3!�fR � �6[ �v6[�N! �n (�X* � � K$7�����>[F��� ����3!3#� � " � � uR�� � �6[ " � �6[ �H�/ ��6[� "5X* #$# Y%"��1����� � ��h(�X+*�� � Y � �6[ � � � (�X+* ��� YJ^ �H]��fR��+������3#��%R*���%$� �)���>R1aH�� ��'"]�N>ae������ "�[�/������N U �f[ U ���� � �����h� R �.� � +��� � � ��� �B[�����p$7�>R "2��� � � � ������� U �H��N,$7N�[��tnrh,��]��.R U ����������3#q_R*N!��\[�$7N! � ��>R U N#�6[���\$7�>RNZn �-��3#���pR�] g hA��]����DN�R�� U � JR*���,N#����N#6R-�,� � �\R U N�R�R*� g ����^��H]��>R*�� �����fR � �� � �pR�N g\� R��f[&N#�� ��� �1nr �� ����\$7���>R1NZneaHN# J[�R " �)N!�+N#����N����/� nr �� ����6$7���>R#"�a�])�%$J]I� � ���+��]���� U R�h)$J]�N!��N!3!��q$ � ����hC��� U � � 6R*� g ��� � R����\[6$7� g ��� � � ( �����>R (&�B��6R*]���N*"�X+*���* �����6[�/ JR�N#� "4X+* # � YJ^ �-������j�/��� � ��hA]���� R��/�tn4a � ����>[ "���� � �I� � ������� U � U �� "���] � �������H�pRH���6$SN!�6$7�/��� �Zg ������] � � � ��h,]��q� � � $SN!��p[Fa�����]�N!��BR U �>$7� � �5���KN# �� � � ������ � ����]��0R � �,�+ �����>R�� (�j�/��� � ��h'"6X+* � �'" U ^�X � � Y� �6[ $ � �����f[&nrN! 1nr� ���]��� � ��fR�� � J$J],������N.��]��+ �����fR �� �� �.��� ���+��� � ����>[ g hF��]��+�������/ � ��� � [�����^

1) ���N#6R���h'"- ��fR�� � J$J]��� JR0������N � R*�� ���3!�� � .� � U�U ����3VRA] � ��� � U�U � ���������h U � �p[ �����������]����>[E��NQ]��pR&a � ��)����3)^ �H]���1����� � ��h (�X+*�� � Y" �����>R"] � ��� g ����� \R��>[������ � ���N!6R U R�h�q$c]�N#��N#3!�%$ � �KR���6[���fRW��NAN U �/ � ����N#� � �������B��]��B ��/3!�� � �qr��m)$7� U ����N#�,[�pR������6$7����N#� "!�,NVR��1��N!� �Zg ��h��� � � �N#� � �6[ yV�� � aBR*N!� � R (�X+*�� � Y U ��N#������ �����3 R���\[h'"ia�])�� �� � � � �3!�D ���3#�� � ����*h'���K�>$7�a � RA �� U N! ����>[���� U �N!����6$7� � ����N!��� � ���/�6$7���fR �� ���3#�� � ��aHN! u[�R"aH�� �� U �N#��N!)�6$7�>[En � R�����

g h']�� � �QR� g �*�>$7�JR+��] � � � ��m)$7� U ����N#� �6aHN! u[�R7^ �H]��%R+ ��>R�����+a � RAR*��������N �>R*� �>g ���pR�]Q��]��� U R*h�$J]�N!��N!3#�%$ � �5 �� � �����*h���NZnW��]��0 ��/3!�� � �qr��m)$7� U ����N#� [�%R*�����6$7����N!� (�1N#����]�� � �� "4X* � # YJ^

�BNZae������ "2��� � nrN!����N>a�q U R*��6[h "�1N!����]�� � ������ � �_^ (�X* � *2Y1n � �����>[F��NF �� U ���p$ � ��� � � �N!�� �6[by��� � aBR�N#� � R,(�X+* � � YO ���3#�� � ����*h,���5�f$7�+��� � ����m��%$ � ��[�>$7�pR���N!��� � R �5^ 1N!����]�� � ��+�/� � �_^(�X+*���*�Y-] � [F$J]�N�R*��� � R�N#�,��a�] � �1[���K�� ������1[� �6�)������N!�"N>n4 ��/3!�� � JR � �6[&�/m�$7� U ����N!�6R "!6R�����3� �,��m��� ��BNZn � � � � R (�X+* ��� Y � �6[�j�/��� � ��h�� R (�X+*�� � Y� �����>R7^ � 3 � ��� "������������0$7N#�6R��p[�� � ����N!�a � R�3!������� ��NC��]�� U R*h�$J]�N#��N!3#�%$ � � U � � 6R�� g �������*hCNZn1��]��>R��0������3#��%R*���%$B �����>R#" � ����])N!�3#] 1N!����q]�� � ����/� � �_^ (�X+*���*2YO[�p[,�� �hD��N,� � ���%[ � ���0]��pR�R*����NZn1�/m�$7� U ����N!�6R g h [���DN!�6R*�� � ������3*"���� �U ����N!�BR���6[h'"���] � ����]���h,ae�� ��O �� � [I�,N# ��0R*��N>a���hC��] � ����]��0 ���3#�� � �aHN! u[�R7^

#_� � � � ���/ HR*��6[�h'"�� � ����� (�X* # � Ye[�%R � 3# ����>["a�����] g N!��]�� � �N!� � �6[Iy��� � aBR�N#� (�X* � � Y� �6[ 1N#����]�� � ��A��� � �_^)(�X* ��*�Y%"- �� U N! �������3'��] � �A]������/m U �� ������6$S�>[�[N! g � � RT��N'a�]�����]��� R�N!�D�"NZn���]��C��m�$S� U ����N!��aeN! J[)RT6R*�>[x���b��]��>R*�CR���\[���>R+ae�� �� U � ����p$7�� � ���h���m)$7� U ����N#� � ���( � � ����� "4X* # � " U ^ � � YJ^ ��� U �N U NVR��>[����6R���� � [,��N,$7� � R�R��tnrhDaHN! u[�R � R���m�$S� U ����N!�6RH� n-��]����� U �N#���\$7� � ����N#�6R�ae�� ��.���%R*���>[ ������]��,X* ��* �Bm2nrN# J[ � � U �/ g6� $ �� ��%$7����N#� � �h���� �+R�����3,��])�%R$7 �� � ��������$7 ������/ ���N#� "�]��O$7� � ���,�>[0��] � �1N!����h `���� NZn�1N#����]�� � ��1��� � �_^ � R (�X* � *2Y1aHN# J[�R1aH�� ��

� � &8)F;� �72�4����=��5�!(���7/��9�7!? � J'7/ �% J �$9H7/�8� � I2� �2)*� ��� (�&�) % �"=D(���7/���$ � �@?E(�&�) J 72 �% J:�!9F%4)B) �H)>%� %4��� =�����('(�76;� �7/��72����=�) �87/ :&��$ �%A(�7 �).=�7/I2����K*)EJ:&�)*� �)>�2%���+�� �! �4�C� �M,>-�� � �2; L � �41*L

Page 172: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��4����� �e���� �4���+� � � �1���4������������� � � ���T� � � �H��� � ��� X � *

� $7�� � ����hC��m�$S� U ����N!�6R " � Rvae�� ��0N!�)��h�X ��� N>n � � �N!� � �6[�y��� � aBR�N!� � R (�X+* � � YeaHN# J[�RS^����� � ����h ";��� � $7N#� U �� � ����N!� � ��R*���C�� � ����N#��NZnB �� � [����3 � ��N!6[-" �v��3#3!� � ��� � �_^)(�X* #$# Y

[�>$7�p[�>[+��N+\R�� � [���K�� ������R*����NZnK �����>R � 3 � ��� "V$7� � R�R�� nrh����3BaHN! u[�R � Ri��m)$7� U ����N#�6R g6� R*�>[TN#�� R��/�HNZnWR U ����������3!q R�N#��6[,� �>g ���>Re[�����%R*�>[ � � h�� � uRj� � ������� -nrN! e6R��O��� �Ty&R�$J]�N�N!�pR ( � � ��� ���� � � ^ "5X* � � K$7�����>[,��� �v�/3!3!� � ��� � � ^ "KX+* # # Yu^

�H])�IN#��]��/ A� � �*N# � R�$J]�N�N!��N>n+��]�N!�3#]� �i��� ��]��,�������/ � ��� ��DN!��]�N>a���N�N U �� � ����N!� � ��q�����B��m)$7� U ����N!�\RH$7� � R�R*� �6�fRH��]����PN!� ��]�� g6� R��%R�NZn � � � ��� �Zg ���(���&��� ����� � � a�����] ������3!] g N#� �����3aHN! u[�R (&�B��6R*]���N*"eX+* � *2Yu^����/ ��'"4��m)$7� U ����N#��aHN! u[�R � ��D[� �6�)�>[b��N g �,��]�N�R*�,a�����] U �N!q���\$7� � ����N#�6RA��] � � � �� ���6$7N#�6R��pR�������.a�����] �(� � �e������3#] g N#� �����3 ( � ^ ��^ "-R����,��� � ���h�q_R U �/�����f[ YaHN! u[�R7^���N# -��m � � U ���'">��]�����m)$7� U ����N#�C8 � = �pRi���6$SN!�6R*�%R��������-a�����]"�,N�R*�-NZno���JR�������3#] g N#� �q����30aHN# J[�R (r��^ 3)^ "�� � =���� � = " � �6[���8 � = Y%"�a�]���������])�� ���3!�� � � �� � = �%R1$7N#�6R��pR����/��-a�����]�,N�R*�H������3!] g N!� uR ( �� � =�� ��8 � � = � �6[ �� � = Yu^

#_�.$7N#�,�>R � RT��N'R�) U ��%R��D��] � �T��]��%R0[� �6��������N#�E[�/�������/ JR � $7N#� U ���/������h�[����K�� ��/��0R*���NZn1��m)$7� U ����N#�,aHN# J[�R���N"��]�� � � ( �����>RS^�� � ��/ � �6[�y�� � ��N>��p$c] (�X+* #�� Y 6R��>[ ��]�� �>g N>���$7 ������� �� �"� �\[InrN!��6[ ��] � �"X � NZn1��]�� ` * �1� ����� ���HaHN# J[�RB6R��>[ g h 1N#����])� � ������ � � ^ (�X* ��*�YaH�� �� � $7�� � ����h,�/m�$7� U ����N!� � ��( ���6$7N#�6R��pR����/��SY g h,��]��pR�$7 ������� ���N#����^

�OR����)3 �B��6R�]���N � R (�X+*���*�Ye[� �6��������N!� " � � �>g6� � � �6[ ��$ 1������� � �6[ (�X+* # �!Ye$7N#�6R��� �6$S���>[� ���%R*�IN>n" ���3!�� � � �\[ ��m)$7� U ����N!�(aeN! u[�R,��] � ��] � RI$SN!�,����N g �Qa��%[�/��h \R��>[ � R ��]��N U �� � ����N!� � ����� � ����N!�QNZne ��/3!�� � JR � �6[x�/m�$7� U ����N!�6R�������]��C$SN!�����f$7����N!���pR��+�������/ � ��� �� ( ��^ 3�^ "��� �-� � )� + ��$ 1������� � �6[ "6X+*,* ` �W� � ����/� � �_^ "4X+*,* � 4y����p[��� g �� �3 + ��$ 1������� � �6[ "5X* # *2YJ^ ]������T��]�� � � � ��N!3#h � U)U �N � $J] � U)U � � JR � � �6 uR��B��N g � � [� U � ���� ��Tnr �N#� ��]��.�%[� � ��] � ���]��� ���3!�� � uR � �6["��m�$S� U ����N!�6R � ��+[�� �6���>[Aa�����]" ��>R U �>$7�1��N � R����1NZn U �N!����6$7� � ����N!�C �)���>R "g N#��] �����\[�� JR*N!� (�X* # � Y � �6[ ��N�R*��� g �� �3�(�X+* # # Y.] � ��� U N#�������>[bN#��A��] � � "-���Q�>R�R*���6$7� "��]�� � � � ��N#3!h � U)U �N � $J]��%RH� ���� � ���/��e��N"��])�T �����/q g6� R��>[ � U�U �N � $c]

#_�T�pR U NVR�R*� g ���,��N'[� �\���F���/ JR���N!�6R+N>nB��]�� � � � �6[ � � � ��N!3!h R��� � ����3!���>R+���R�6$J] � a � h���] � �.��]���h�N#����hQ[����K�� 0���Q��]��DR�� ���CNZn���]��,��)���0NZn �� � �6R�� � ����N!�( ���/�6[�� uR�N!�&"5X+* # � " U ^�X ` �!Y

#_�Q��]�� � � � ��N#3!h � $�$7N#��� "i��� U ���p$7� ��� �����>R�� � �� R U �>$7� �6�>[���] � �T\R��,aeN! J[� �� ��� � � � R

� % (#��9 =D�� ���7/�89E(�7A��7/(�) (�&��!(E�!�<�!��7/I � (�&�)*72 ���9�(�9E9�(��C��� ��9�)6(�&�)6(�)* �H9�� �)*I/�8�"�$ ���( ���M�!��%�� =�72��9���9�(�)*��= ���9��5%4)�G � �2G 9��5%4)/L���72 ) 8� �H;���) � 9�7��A)6J 72 �%496�! �) =��5�$9�9�����).%��!9�� �)*I2���5�! E����=D7/��9��C9�(�)*�4(��'+��#����9�&��/7 � ,.-��/-21��) �/)*��(�&87/��I2& (�&�) =�72��=�)*;8(�7!?�� �)*I2���5�! ���( ���2�C9:9���;�;<7/9�)>%4����9���;<)* �9�)>%4)>% ���H(�&��!(:7$?�� =�7/�89���9�(�)*��=�����L

Page 173: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X ��� ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

��]��+)�����1NZn $SN!� U � ��pR�N!�&"���\R���� � ["NZn 3! � U ]����D�>R7^�# �C���K�>$7� "���]����&"��])� � � � ��N#3!h R*�� � ����3#h� �%R*N R U �>$7� �6�>R � g N�[h(N>n. �����>RFa�����]( ��>R U �>$7�,��NEa�]��%$J](��m)$7� U ����N#�6RF$ � � g �E[�� �6���>[K^� ��"��]��>R��C �)���>R+�,N# �� U R�h)$c]�N#��N#3!�%$ � ����h � �� � � �5��] � �E��]�� � � �����>R $ 1N!����]�� � ��.��� � �_^(�X+*,* ` Y � �3#�����] � �,��]���h � �����N#� " g �>$ � 6R��'���C] � R g ���/�(R�])NZa��(��] � �DR����������>[E �� � [�/ JRU �N#��N!��\$7�b�)N!��aHN! u[�R,6R�����3���]��Q�,NVR��D$7N!�,�DN!�($SN! � ��>R U N#�6[���6$S�>R � � ��]�� � � � ���)��� ���������� " � �6[ g �>$ � \R��'R�� *n � $7� [h)R����/m�p$�RT�,�pR U �N!��N#��6$7� ��m)$7� U ����N#�EaHN# J[�RC��� � � � �����/ ��] � �+R*�3!3#�>R��uR#" � 3 � ��� "���] � � � � eR � ��0��]�� � $7�� � � U �N�$7�>R�R�����3F)������6R*�>[ g hD]�� � �6RS^

#_� � ��>$7�����0[�����/��N U �,���������Q��]��C�������� � ��) ��'" 1N!����]�� � ��0��� � �_^)(�X*2* ` Y U ��fR��������>[ �R�h�� g N!���%$.R�h)R����/� ��] � � � $7�� � ����h�� ����� � � � � �����>R7^ �H]��pR0R�h)R����/� U �N>��p[�>R � $J] � �\$7���N�$SN!� U � ��C��]��C��m)$7� U ����N#�6R+��] � �" ��>R*����+nr �N#� R*6$J]E��� U �� ��p$ � ���th'[�/���� ��,�����f[I �)���>R0��N��]�NVR��,��] � � � ��%R*�Fnr �N#� ��]��C������3!��pR����%$A �)���>R U ������N!6R*��h�6R*�>[ g h 1N#����])� � �� � �\[bN!��]��� [ � �� �N!����%R*�JR7^ ����3# ������ �Zg ��h'"���NOR�\$c].$7N#� U � ��%R*N!�0a � R;� � [� g h 1N!����]�� � ������ � �_^'(�X*2* ` YJ^��N>aH������ "���]��/h"[�p[A ������ � ���] � � "!NZno��]�� � # *����DN!��NVR�h���� �>g �%$1aHN# J[�Ri���"��]��/�� ��� � ��������3.$7N! �qU 6R#" � X!^ #�� ] � [ g �/���'$7� � R�R�� �6�>[ � Rv�/m�$7� U ����N!�6R�2��] � �B�%R " �#` � aHN! u[�RHaH�/ ��+��N#�B$7N! � ��>$S����h� � U�U �>[ g h'��]��"���6[6$S�>[ � � s �����>RS^Ay����p[��� g �/ �3 � �6[ ��$ 1���/��� � �6[ (�X* # *�Y+6R*����3D��]��R � �D��$7N# U 6R � �6[F��])� � � � ��N!3#h"��]��/N! �h "[������� ��,���)�>[+��] � �j��]��� ���aH�� ����*6R������1��m)$7� U ����N!�\R( � �\[I��])�%R�R��/��N!����h �&��� ���!��������N>���� �� � U�U �>[,a�����] 1N#����])� � ������ � � ^�� R � Rvae�����rY �

��������� � � � � � � � �% �

# �.R*��,� � �h'"J����������� � 3! ������,�/��6��m��%R*�JR5���0��]��-��� U �� ��p$ � �/N! ��,N�[���������)3j�������� � ��� ��-N!�.a�]��%$J]aHN! u[�R0$7N!�\R�����������F��]��CR��/�TN>n���m)$7� U ����N#�6R#"K��� g N!��]E��]�� �-��3#���pR�] U � R*�T�����6R*�F3#������ � ����N!�� �6[ aHN! u[ U �N#���\$7� � ����N#��� � R��)R7^

�H])�>R����\�6[���)3�RH$ � ���6�����N ��>R�����N#�,N!���ONZn���])���,NVR��e��� U N! �� � ��1�����%[�/���� � �)R� U�U N! ��uR$7�����>[ nrN# "��]��'[ � �H �N!���� ��]���N# �h F��]��, ��/3!�� � ����*hb���K�>$S��^$#_�E��]��D�������� � ��� ��, ��/�����aH�>[

�Zg N>���'"5���O] � R g ����� R�]�N>a��Q��] � �0��]��"��m U �� ����,����� � �4����p[���6$S�wnrN# 0��]��" ���3!�� � ����*h ���K�>$7��%R g6� R*�>[bN#� � a��p[�F� � ����/��h'NZnB���6$7N!�\R��%R*������� � �6[ U R�h)$c])N!��N#3!�p$ � ����h���� U � � 6R*� g ���AN U �� � q����N#� � ����� � ����N!�6RHN>n-��]�� � ��/3!�� � � � �6[ � ��m)$7� U ����N!� �$SN!�6$7� U �JRS^

#_�6[����>[ "4��])� � U ���N! �� � � ���p[���*h�N>nB��]��D[ � �1 �N!)���,��]���N! �h��%R U ��>[�%$ � ���f[�N!�E��]�� � R�qR��� U ����N#� ��] � �+��]��k$ � ����3!N# ����>R � ���3#�� � � � �6[ � ��m)$7� U ����N!� �N g �*�f$7����������hC��m��%R��/^���N>aH�/���� "N!�E��]�� g6� R*�%R0NZnB��])�F ��������a �Zg N>���'" � �6[Q��]��C ��>R*����uR+ �� U N! ����>[����Q��])�%R+��]��fR��%R "4��]��pR � R�q

Page 174: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��4����� �e���� �4���+� � � �1���4������������� � � ���T� � � �H��� � ��� X � X

R��� U ����N#�0��N>a R*����� R ��>R*����N!� �>g ����4N#����$ � �"NZno$7N#� JR*� �.� � +��� ��$7N#3!�����������1� � U�U ����3�R4������� �� RjN>n1 ���3#�� � JR � �6[ ��m)$7� U ����N!�\R#" g ��Ba�] � �������%[����6$7�+�pRH��]��/ ��0��] � �+��])�>R��.$ � ����3#N! ����>R] � ��� � ��h U R*h�$J]�N!��N!3#�%$ � �4� � ���p[���*h $

#HaeN!��p[�R*�3!3#�>R��0��] � �0[ � �� �N!)��� � [���N�$ � ���>R������f[I��NC��m � �,�����0��]��pR ��>R*����N!��a�����]�,N! ��� ���3#N!� e��] � � ] � R g �/���,6R*�>[&���,��])� U � R��/^ �B���B�����>[)Rj��N��6 JR*�H ��>$7N!�\R��%[��� 1��]��B�%R�R���NZnO]�N>a���N U � � 6R*� g ��hEN U �� � ����N!� � ��� ��� ��]��'$7N#�6$7� U �ANZn � ��m)$7� U ����N#�6R��4��� � R U �f$7� �K$,� � R��-"� �6[���]���� "66R�����3C��]��pR�N U �� � ����N!� � ��� � � ����N!�&" ���q �/m � �,�����O��]��.��� U �� ��%$ � �5 ��>R�)���JR� ��/�����aH�>[�Zg N>������N"R��/��� n4��])�� �� U N! ����>[,R*h�R*����� � ���p$H[� �5�/ ����6$S�>R g �/��ae�����" ���3!�� � uR � �\[F��m)$7� U ����N!�\RR�� �������>R7^

�H])�� ��>R*� � u$c] �� U N! ����>[ ])�� ��'N!� $7N#�����>$7����N#���%R*� � R*�� ���3!�� � ,� � U�U ����3�RCR�)3!3!�fR��JRR�N!�D�+�%R�R���>RH��N,$SN!�6R*�%[�� �a�])���'[��������N U ����3"R*6$c] � ��N U �� � ����N!� � ��� � � ����N#�4^���N! B��m � � U ���'"�������Q�tnBN!�)� � R�R���,�fRT��] � �A]��� � �6RA[�N����6$SN�[�'R�N!�D�&nrN# �� NZnB ��/3!�� � �qr��m)$7� U ����N#��[�%R*q�����\$7����N!� "5N#���D$ � ���)N!� � �%R*N � R�R*��,� ( � RTa � R0[N!�)�,��� � ���-��]��,R*��6[����>R+ ��/�����aH�>[ �Zg N>���!Y��] � � �����6])� � �6R����6$SN�[�A��]��CR � �,�.[�%R*�����\$7����N!�4^ � � a����)3 � � � � � ��N!3!h���N $7N#�����>$7����N#��q�%R��"�)���*aHN! ���R "-])� � �E���6[����p[ � �pR � ���,NVR��"$S�� �� � ���)��h�] � ��� [� �K�� ������ � R�� � �������3QR*� � ���>R�� "��� � �������3 R��� � ����3#���>R "i��� � ��)����3 $SN!�6R*�� � �����JR " � �6[b��� � �������3D��m U �� ������\$7�>R7^"# �O�%R+N!����h� �� � qR�N!� �Zg ���F��N � R�R���D�"��] � �T���6[����p[ � �pR�aHN#��%[����\[6$7� � a��%[�" � ��3#�,NZnv[���K�� ����� � �)���>R��

nr �N!� � $7N!� U ����m g N�[h"N>n�[ � � � ( � R-] � R g �����D[���,N#�6R��� � ���>[0���C$ � ����3#N! �h"��� � ������)3+� � R��)R#"��^ 3)^ " � N�R�N>n R���h'" � � ���,�� �� "'+ ��$ �+���)����h'"6X*2* � Y � �\[I]����\$7�0aHN!)�%[,] � ���.[���K�� �����BR*���JR�NZn��m�$S� U ����N!�6RS^

� � � [)[������N!� � ���%R�R*��A��N $7N#�6R��p[�� B�%R�]�N>asN!���k[������ ��,�����>R1��]��. � �)3!�"NZn � ������ �� � �������� � U�U ����3VRH��] � ��]�� � �6R � �� �� �� �e��N"���\[6$7�0��� � � � R��'R*6$c] � RH �� � [����3 �-��3!���%R*] � ��N#6[5^���)�H���\[�� ��>$7� � U�U �N � $J]"�,��3!]�� g ����N U �� �nrN# �� � 3#������ � ��� � � ����N#�T���>R�������3 ��N!�"]��� � �6R�( ��^ 3�^ "g h. ��>$7N# J[����3+��]��� � ��3!�BNZn U �N#���\$7� � ����N#�6R-� � ������� �-��3#���%R*]CR U � � ���� JR-3!�����H��NT�)N!��aHN! u[�RcY��NC$7N#�6R��� �6$7�B��])�AR*����NZn � ���K���6[�6$7� g ���+� � U�U ����3�RS^

�B���������]��B �� � ������h0N>n4��])�� ���3!�� � ����*hA���K�>$S�-�%R (r ���q*Y*R* g R*� � ����� � ���>[&���F]��� � �CR� g �*�f$7�JR "��]��0$S� � ���GNZn ��]��w[ � �K �N#����0��])��N! �hF��N � $�$7N#����jnrN! e��� U �� ��p$ � � g ��] � ����N#� H��] � �B$SN!�����f$7q����N#���%R*�������*aHN# �)R�$ � ����N#��a������ g �A���'[N! g ��^ � �6� � � $7N#��� �� g �����N!� NZn1��]��%R�aHN# � �%RH��] � ����A] � RA]���3!]�����3!]����f[b��]��pRA� � �*N# T��]���N# ������%$ � �HaH� � �����>R�R0���E��]��'[ � �� �N!)���,��]���N! �h'" � �\[nr� ���]��� ��DN! ��B��] � �B�����%R �>g ���0��N,R*�3!3#�>R�� � �,����]�N�[N!��N!3#hFnrN! B ��>R*N!�������3"���/^

Page 175: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � ����� � ���E� � � � ����� � ��� ��� � ������� � ���������

Page 176: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � �� � ��� �

� � � � � � � ��� � � � �� ��� � � � �����

� � ��� � � � �

� ��� � ,� �� � � � � � �� � � ����� � ��� ������� �� � ,�

� � �!� �"$#�%�� � % �&�

� �>g ��� � ^�X2 � � �>g6� � � �\[�'�$ 1������� � �6[�� R�(�X+* # �!YWR�����NZn � # ���3!)� � � �6[A��m)$7� U ����N#�AaeN! J[)R7^

( �*) � � ��� +-, � � ���!���N#�� � � ��� g 6R �� U � � �� �,N>��� g N>a�� �N#6R��g ��3 U � � $7� g �N ��� R���� U g N#��] U �� g �N � [ R��/ag �>R�� U � 3#� g � � � R � � � g �� � � U ���� g 6R*] R*]�N��$7� � R�R R���� [���>[ R�� � � $c]�N�NVR�� R � �%[ [� � n R U N�N �$ � �,� R*��N U [N#�JR R*������ $7N!�,� R � h)R [N!��� R�a � � U[�%[ R*N�N!� .6N � � R�aeN! �� [N R�] � ��� .6N�N�[ R�a � ��������� a�]��p$c] 3! � U � �� ����� [�N��>R a � ��� 3# �N�R�R ��N#6$J][ � �� aH�/� � ����6$J] a���� [N!��� a � �J$J] ��N�R*� a � [n � $S� a�����] U ����� aH���p[ nrN�N#� ae�� �� U � � a � �6[3!N!� a�]���� n � [�� a � m 3#����� a�] � � U ] � R�� a � R*]3# �N# U a� ������ U ���u$c] a�����3 3! �� � � aHN# J[ U ���� aHN�N#�])��� a������ U �� U a � ��� ] � ��� aHN! �� U ��N>a aHN# ��

X �#`

Page 177: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � ������� � ����� �� � �� � ��� �� � ��

� ��� � � �%����% � � ����� � � � � �� � ,� � � �!� �"$#�%��� % � �

� �Zg ��� � ^ � ��B��6R*]���N�� R (�X+*���*�YBR�����N>n�� ` ��/3!�� � � �\[I��m)$7� U ����N#�,aHN# J[�RS^

( �*)�� �'��� +-, � � ���!���g6� ��] [��)� �,N�[�� R�N#��� g N!��] [N!��� �,N>��� R*N!�,�g ���Sn nr����� �C6R�� R*N�N!� g ����� nrN�N#� �,N�R*� R�N�N#�g �����>[ 3!N � [ ��N!��� R U N�N!� g ��N�N�[ 3!N�N�[ ��N!�)� R U N�N �g ����>[ 3! ������ U ����� R���� � � g �� � [ 3# �� � � U ���� R*��� � �g � ] � ��� U � � ��� R*aH���/� g )��� ] � ��� U � � �%[ R�ae� � �g 6R�� ]�� � � U N# �� ��N#�%[ g \R�] ]�� � [ U N�R*� ��N!� g$SN!�%[ ]��/�>[ U N�R*] a � ��� $7N!� g ]�N�N�[ U 6R*] aHN�N#�$SN�[� ])N�N U U �N g � ae� � � $7N!�D� ]�N�N>n U �NZ��� aH� � [�� � � ��N g � U � a������ [� � [ ��N�R�� U )��� a����%[[� � � ��N�[� R*]�N! �� aHN# �� [� � n ��N>��� R�])NZ��� ae�� ��[ �� � � �,���p[ R*N!��� [ �� � [ �D���%[ R � �p[

Page 178: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�� � ��� � � � � ��� X ���

� ��� � " � � ��� �� � � � ��� ����� �� �� %�� � % �&�

� �Zg ��� � ^ ` �-� � �� � �6[ '�$�1������� � �\[�� R (�X*2* ` YBR*����NZn�� # �)N!��aHN! u[�R7^

����� ����� � �� � �� g N>��� �)NZa�� ��N#6R��nrN!��] ����� g N � [ ����a[� � � R��� nr6R*] $J]�N��g N�N�R*� ] � �p[ �,� � n R*��N�N��U N!�,� � � h)R nrN!��� [ � � U�,N � � ��� g N�N�[ R�� � ��U N��>R g6� ��� �� �N�R�R �,N#6$c] �N!��� � � �J$J] �,N�R*� � � [U N�N#� ���� �� ��� � � � �6[�,����� [ � � [ � R�� � � R�] �� � � ��N! u[ U ])����� g N�N!�� � ��� g N! �� $7��N>a U N! ��

Page 179: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X ��� ������� � ����� �� � � � ��� �� � ��

Page 180: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � �� � ��� �

� ��� � � ��� ��� � � � � � � �����

� ���� � ���

� � � � � "�� % � "-# % �

# ����]��%R � U�U ���6[��m " #BN!��������)�A��])�,$7N#���������N>n U � U �/ JRTN#� � , � � ���!��� �4����� ���!� )&��] � � #+$7N#q� ���]�N! ��>[F[�� �����3+��])� U �/ ���N�[,X*2* � q�X+*2* � "���N#3!����]��� -a�����]"�,��� g �� uR5NZnK��])� 1N!�����f$7����N!���pR���v�>R*� � u$c] �� �N! U � �B��]�� ���)������ uR����*h"N>n� B����/�6R�� � �6[5^�(])�����e��]��eaHN# �"[��>R�$7 �� g �>[0���"��])�%R4��]��>R*�%R;nrN�$S6R��>R�N!�"��])���%R�R*��HN>nK]�N>a($7N#�����>$7����N#���%R*�

R�h)R����/� R �1� � �1� � � � �+��m�$S� U ����N!� � �6[M ���3!)� � U � ������ ��6R#"+��]��Q ��>R*� � u$c]( �� U N! ����>[(��� ��]��nrN!����N>a�����3 U � U �� uRi�������>R*����3 � ���>[+]�N>aE��m)$7� U ����N!�\R � �� �4����� � � � g h.$7N#�����>$7����N#���%R*�i���/��aeN! ���RS^y U �>$7� � $ � ����h'">�%R�R���>ReR�6$J] � RH[������� ��,���)����3�a�]��p$c] U � �����/ ��6R g �f$7N!�,� [h�� � �,�p$H��m)$7� U ����N!�\R( � �\[�a�]h6Y�[�� �����3,�����*aeN! �D�� � ��������3*"K��]��k[�����/���� ���N!\RH���K�>$7�JR���m)$7� U ����N#�6Rv] � ���0N#����]��R U ���>[ � �6[ R�6$�$S�>R�RAN>n0��� � �������3*" � �\[ R��� � ����3#���>R g h a�]��%$J]�N!���'$ � � ��/�,�>[� � ���C��])�>R�����K�>$7�JRS^-'�6$J]IN>n1��])�%RHaHN# � a � R�$ � � ����>[CN!��B6R�����3���q � q�� ���6$7N�[��� JR ( �w ��3!��h � �-"4X+*,* � �5�%R����� "4X*2* � g Y � RBR���� U ���B���fR�� g �>[)R7^

�H])�"���6R*��3!]��JRB��] � � #H3 � �����>[�nr �N!� ��]��pR� ��fR�� � J$J]�( �V^ 3�^ "5 �)�,��� � ����N!�6R�N!�Q��]��.��N!����N#�NZn ��m�$S� U ����N!�6R-��� � $7N!�)���>$7����N!�)�%R��1nr � �,��aHN# � ���pR� � ����� � ����N!�,���>$J]���� ��>RinrN# ���m � �,���)����3��]��0�������/ �� � �5 �� U ��>R*����� � ����N#�6RjN>n-���/��aeN! ���RJY1���>[F��N � � �������� ��>R��e��� ��]��O�������/��hC[ � �4 �N#����[� g6� ���'" � �6[,��]����\$7�0��N"��])�TN# ���3!��� � ��aHN! ��, �� U N# ����>[,��� ��]��pRH��]��fR��%RS^

�H])� � ��� NZnO��])�%R"NZ���/ �������aG�pRA��NQ3! �N# U ��N!3#����]��/ � ����N!) FaeN! ��N#�($7N#�����>$7����N#���%R*�

X � �

Page 181: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X �$# ������� � ������� � � � ��� � � �� � � � � � ��� � � � � � ���� � � � �

��m�$S� U ����N!�6R "�R�N.��] � �H���-3!�����>R ( ��N#3!����]��� 1a�����]F��]�� g N�[�hFN>n�aHN! ��" �� U N# ����f[&���F��]��%R-��])�>R��pRcY� $7N!� U �������BR���,� � �h"N>n-N#� � ��fR�� � J$J],N!�'��]��pRj��N U �%$ " � R�aH�/��� � R � $7N!���������������1R�� � �������3U N#�����HnrN! B��]�NVR��0a � �������3C��N"�/m�����6[,N! � �� U ���p$ � ���+��])�%RHaHN# � ��^

� ��� ��� ��� # �

�H]�� �6 JR*� U � U �� ,��] � � # U g ���%R*]��>[ N#� �/m�$7� U ����N!�6R (�� � � ���� "0X+*2* � YCa � R,���6R U �� ��>[ g hN g R*�� �� � ����N#�6R g h �5�pR����/ ,(�X*2* � g Y,( � �6[Q� � ��h N!��])�� JRJY���] � � g6� $ � U �N U � 3 � ����N#�E�����\[�R+��N��� � �� U � �����/ ��6RF��� � �� � ��������3 R���� � � � �(����/�����( � ����QR�N#�,��a������ g �b� � U�U �>[ a�����]3! �� � � U ��>$7�%R*��N#�E���� �h ��%$����h'"ia�])�����DN!��])�� JR � �� � U�U � ��/�����hE��m)$7��6[�>[�nr �N#� ��� � �������3( �_^ ��^ " g �>$SN!�,�� [�h� � �,�%$+��m)$7� U ����N#�6R�� Y � �6[�� � ��� � ��N#��3 �����D�+��N,���6$7N# U N! � ��� "5�tne��])�%R��%R� $J]��������f[ � � � ��� ^ �H]��pR U �N U �� ��*hQNZn g6� $�� U �N U � 3 � ����N!� $ � � ��� � [Q��N���N#��3 $7N!������ �3#���6$7������D�>R-N! B������� � n � ����� ��+��ND$7N!������ �3!��^

�H])�%R4N g R*�� �� � ����N#�A] � R g �����.� � [��-NZnr�����A���T��]��1�������� � ��) �� ( ��^ 3�^ "���� U � U �� uR-[�>R�$7 �� g ���)3� U�U ���%$ � ����N!�6R��'�N! ���+�1N���NVR � a � "-X+* # *" �4�>R � � �N +�yV���*��N>aBR���� "�X+* #$# Y " � �6[���]��"6R� � �R�N!�������N!� U �N U NVR��>[��pRH��NC��� U �����,�S���HR*N!�,� ����6[IN>n �&��� � � � � � ��� � ����!��� � � � ��� �*)���-��] � �+�%R "U ��>R*�����H��m)$7� U ����N#� U � ������ ��\RH��NC��]��0�����*aeN! �D�,N! ���N>nr����� [� �����3"�� � ��������3)^

�H])� U �N g ���/��a�����],�,NVR�� U � ������ �� R������>$7����N!�DR��� � ����3#���>R ( U �N U NVR��>[, U ��NA��] � �������,�!Ya � RH��] � ����]���hC������]��� � R�R���D�>[F��� � [� � �\$7�0a�]��%$J] U � �����/ ��6RHaeN!��p[ g �>$SN!�,�B��m)$7� U ����N!�\R[� �����3+�� � �������)3 (ra�]��%$J]A�pRi�������������h���N+]�N!�p[A���.3!�����/ � � g �>$ � 6R��'" � RinrN!��\[A���A��]��%R���]��>R*�%R "N!���B$ � ����N#� � ��a � h)R U ��>[��%$7����� � [� � �6$7��a�] � �1� � U)U ����3 � �����*aHN# �0a���������6[6$S�!Y5N# "!��] � ���]���h �� ��� ��>[b��]�� ��m U �� ����,�/����� +��N � � � �1� � � � �0��]�� �� � ��������3 U �N�$7�>R�R "H] � �6[q R������>$7������3[h� � �,�p$v��m)$7� U ����N#�6RjnrN! � [�[������N#� � ���� � ��������3)^

#_��� � � ���/ (�X*2* � Y%")# U �N U N�R*�>[ � � � �����/ �� � ������� U � �����/ �� R*�����>$S����N#�,R*�� � ���/3!hC��] � �H] � [��]�� � [�� � �� � 3#�>RvN>n g �����)3�

� � ���N!� � ���p$ "���I��] � ���)N,R* U �� ����%R*��N!� g h,��])�T�/m U �� ����,�������/ -a � Rv �� )�� ��f[

� R���� U ��� "!��� ��] � �B����a � R�R���� U ���B��NC��� U �����C����� � �\[�R���� U ������N"��6[�� uR�� � �6[

� 3!���)�� � � " g �>$ � 6R*�A���B$SN!��p[ g � � U)U �����>[,��N � ��h � � R��,a�����]�N#����DN�[� �K$ � ����N!� ���������������������� �!��"�"��$#&%'� (� �)#��*�+� #'���,#&%'�-%.��� �&�/�/01�*2("�3 �$����3 � ���)�546��7����8013 �$�!9!7�� �����$#�� �:2.�+�*7+�����

7��$���;��7<0��>=�7���?�"@%'?�7�� #�=:2 �:0$�5#&%'�8%�����?�7��*A

Page 182: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� �� ��� � � X � *

� ��N>a�q $7N�R*� "-��� ��] � �A��� � [�[��>[b��N � [�[������N#� � �eNZ���/ �]�� � [b��N'�� � ���)����3 " � �6[ � $S�� � ����h�.� +�1��� � � ����]�� � �,N#����HNZn U �N�$7�fR�R�����3C �� ��� ��>[,[) ����)3"�� � ��������3�^

�H])�T���>$J]���� �� U �N U NVR��>[ a � RB$ � �����f[�� ����� � �%���1����� ���$���*)��!� � (�� � � ���� " X*2* � Y �>^�(����]� (� � �3#���6R " U � ������ ��6R+[�p[ �)N!� g6� $ � U �N U � 3 � ��� � �'�� � �N! B�tn1��]����� �N#�� U ��+� � ����>RaH�� ��"a�����])��� � ��N#���� � �6$7�C� � �3!����N>nB��]����� +� � �3#���0� � ����fR7^ �H]��%R+ ��>R��� ��%$S����N#�����K�>$7����������h$ � 6R*�>[ g6� $ � U �N U � 3 � ����N#� ��N � ��3!��N# ���� U � ������ ��6RA��] � �Aae�� �� � ���,NVR��.$7N# � ��f$7� " � �6[bnrN�$76R� ������������N#� N!��(r�_^ ��^ "�[����N#���+ae����3#]�B$J] � ��3!�>RH��NY U � ������ ��6RH��] � �BaH�� ��0R��������4���6$7N# � ��f$7��^

� � �3!���6R aH�� �� ��� U �����C�������[ g h � R*��� U ��� � [ �*6R����,����� ��N���]��GR*� � �\[ � u[

� [ � ���p$w�/ � �N# Hnr��6$7����N#� �H])�T�/ � �N# vnrN# � �� � ��������3 U � ������ �� +��0�%R+�����������(���Y �

a�])�� ��0���'R*� � �\[ � u[ g6� $ � U �N U � 3 � ����N!�&"

� (���Y���( � ��� ��Y

�(����] (� � �3#���6R "��]��+nr��6$7����N!���e�%R � �,���6[�f[F��N&� (���Y�� ���

��( � ��� �

�Y �tn! &� ��� �

� �" (� � �3#���� N!��]��� �a��pR��

a�]��� ��

���%RH��]��0� � �3!�/�HnrN! BN!�� U ��B������ �-N!� U ��>R��/�� � ����N!� NZn U � ������ �� �

���%RH��]��0N!�� U ��BNZn1N#�� U )����)��� �-N!� U ��fR������ � ����N#� NZn U � ������ �� �

�H])� U �� �nrN# �� � �6$7�+N>n � � �3#���6R1a � R�$7N!� U � ��f[&��N"��] � ��NZnWR�� � �6[ � J[ g6� $�� U �N U � q3 � ����N#� � �6[ � �)N!��])�� U � ������ ��,R*�����>$S����N#�CR��� � ����3!h ( $ � �����>[ � �v� U � � ����������� �HN! ��>[�� '���� �N*"X+*2* � YBN!����]�� ��q � q � ���6$7N�[��� �� � R �5^ �(]������0��]��"�*aHNDN!��])�� ����>$J]���� ��>R�aH�/ ��AN#����h �>g �����NC��� � ��� U ��N *Zq � q * �/�6$7N�[�� uR#" g6� $�� U �N U � 3 � ����N!��a�����] � (� � �3!����N>n � ^ � a � R �>g �����N" ��/��� �>g ��hC��� � �� � � q � q � � ���6$7N�[��� JRS^

#&% �!9!����38�����$7�%'� �<01���*�$7��;%@���&�5�!��?�7!" 7���"����1��3 9��5�!#������$#'��� 7��,3 �@�*7�� =�� #&�53%$ ����7��8�5��� ��#�����#.� �!�&��%����$�$#�53 7��-�*%�� �&�,�$# � 2("�3 �$2.�$#'���-%�� #.�-��7�3 � �$7 ����?&%'� �$�!��?�0��>������, � �<��3'&)( �'�+*�#���9!�,&'�"0.-������$#��&�$7�= �0/21�� �43,A

Page 183: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X ��� ������� � ������� � � � ��� � � �� � � � � � ��� � � � � � ���� � � � �

�(])����� E� � �3#���6R4��� U �N>���>[ U �� �nrN# �� � �6$7�eNZnK��]�� g\� $�� U �N U � 3 � ����N#�,�� � ��������3 � ��3#N!q �����]�� ">��]��BR U ���>[ U a � R-��N#� � Rj3# �� � � � R-��m U �f$7���>[K^ � ����]�N#�3!]DR�� � ������ � �N! uRWae�� �� g ������3��3!�)N! ��f[ "5��])�%R����K�>$S�+[�p[���N!�.R*��N U R*N!�,� U � ������ ��6R0R � ��� � ������3 ��N � �bN U�U N�R*�����C��m��� ����,�( ���\$7N! � ��>$7�SY�� � �����^ � RTaH�/��� "K���0a � RwnrN!)�6[b��] � � � � �3!���6R+������ �N�[6$7�>[ ��� � ���� ���!���

��� � � � �����NE��]����/ � �N# R�) �n � $S�'"�a�]��p$c] � � [�����])�����>$J]���� ��'���6$SN!� U � ��� g ��� a�����](N!��]��� �� � ��������3 � ��3#N! �����]�� Rw��] � � � R�R*��,�>[ � $7N!�������)N!6R0�� � �N! Tnr)�6$7����N!� (r��^ 3)^ "�R��f$7N!�6[�q N# J[�� ���>$J]���� ��fRcYJ^

�4N� ����D�>[� � ��� ��])�>R��QR*]�N! ��J$7N#�,����3VR#" � �)��a �� � �N! ,nr��6$7����N#�(� � ����N# ��>[ ��N ��]��Q� � R �NZn���� � ������)3I�/m�$7� U ����N!�6R+a � R U �N U N�R*�>[ ( � � � ���� +��� � � ^ "1X+*,* ` YJ^ �H]��%R +-, � � ���!��� + � � �����0�� ����!��� ( �����jY1] � [I�*aHN"��� U N! �� � ��� U �N U �� ������>R

� � R+��]��D[�pR�$7 �� U � �\$7h g ���*aH�/���b� � �3!��� � �\[bN!�� U ��.� � ����fR � U�U �N � $J]��>[ ���� �N "4��]���� � �N! BR*��3!� � � � U)U �N � $J]��>[ �/�� �N

� � RH��])�A� � �3#����qrN!�� U ��0[��%R�$S �� U � �6$7h � U�U �N � $J]��>[ ���uRH� � m����C�� � � ���� ( ��^ 3�^ "KX "6���g ��� � �h�qr� � ����f[ � � R ��RJY%"���])�T�/ � �N# +R*��3#� � � � U�U �N � $J]��>[ ��� �6�)���*h�^

�H])� �\ JR�� U �N U �� ��*hE��� U �����F�/�����[ � ���� ���!���.��� � ���� JR*��N#�ENZn G� � �3!���6R � R"��]��[�%R�$7 �� U � �6$7hk[�>$7 �� � R*�>[ "�R*N.[�%["��]����/ � �N# eR���3#� � � (r���������� � ����h g �>$7N#�,���)3 ���/ �NYu^��H]��OR��f$7qN!�6[ U �N U �� ��*hC���6R*� ��>[C��] � � U � ������ ��6RH��] � ��aH�� ����/m�$7��6[�>[Anr �N#���� � ��������3.aH�� ����)N!���p$7�>[

��p$ ����h g hD��]��+�)���*aHN! �� " g �>$ � \R��0��]��/hFaeN!��p[IR*� � ���3!�/���� � ������3"��m��� ��/�,����h0� � �3#�0�� � �N! R���3#� � �pRv��]��+nr� ���]��� ���]���hDR��� � h��>[Fnr �N!� ��]��+nrN!�p[5^

�H])� �Wm)$7� U ����N#���- � �N# �\)�6$7����N!� ( � � � ���� ��/� � � ^ "-X*2* ` Y+a � R+$7N#� U N�R*�>[�NZn ��aeN,��m�qU N#��������� � �5n � $S��N! uRv��] � ����� U �����,�S����>[A��]��0�*aHN U �N U �� ������>R�[�>R�$7 �� g �f[ �>g NZ���

+ � �������� � ���� � ��

������ �����

�H])� �6 JR*�wn � $7��N# � U�U �N � $c]��fR � � R ��(r��]�� �>g R�N#������,[�pR�$7 �� U � �6$7h g ���*ae��������]��"� � �q3!��� � �6[bN#�� U ��"� � ��)�!Y � U�U �N � $c]��fR � ^ �H]�� R��f$7N!�6[�n � $7��N! � U�U �N � $J]��>RA��� �6�����*h � R �

� U�U �N � $c]��fRTX#^�-� U �� ��p$ � �K��� � �������3C��m U �� ����,�/��uRja�����]���� � [���,N#�6R��� � ���>['R���3#��� � $ � ���� ��>[6$S����N#�6R

���Q��� � �������3,�����,�TnrN# A��]�� ��q � q � ���\$7N�[�� "i��� U �N>������3CN!�Q��]��C ��fR�����JR�nrN!��\[ba�����]�

� � �3!���\R (�� � � ���/ H��� � �_^ "4X*2* ` YJ^

Page 184: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� � � � ��� �� ��� � � X � X

#_� � nrN!����N>a�q U0U � U �� ( �5�%R*���� " � � � ���� " + �(�����fR#"�X+*,* ` Y%"!ae�H$ � � ����>[+N#���$7N!� U � ��%R�N#�6RNZn ����� ��N���]�� 1 �NVR�R�-���� �N U h (�� � �� + �(���p$���� �-"1X+* # ���yVN!��� � "��5�������&"�+ �i���/�%R�])�� "X+* # # Y � �\[ B��%$�� U �N U ( � � ]���� � � "BX+* # *2Y"�/ � �N# &nr)�6$7����N!�6R " � 3 � ���( ��>$7N! u[���)3ER* U �� ���N! U �/ �nrN! �� � �\$7�AN#����]�� ��q � q � ���6$SN�[�� �^ � ��������>R*����3 � ����N#��NZne��]��"��� � �������3 [h�� � �,�%$�R�NZn��]�� ��q � q � ���6$SN�[�� .$ � � ����>[�N!��O6R�����3 ��]�� ��h U �� U � � �)� � ����� � ��N# (��- � ��� + ��N�� U �/ "X+*2* � Yw$7N!� �\ ��,�>[ ��] � � "4a�]����������(a � RB6R��>[-" � ��� U � ������ ��\Rw������]��"�/�6$7N�[�� O� � R ��aH�� ����� � ����>[ � � � U�U �N>m��� � ������h"��]��.R � �D�T � ���'"]��/�6$7� � ��N!�%[�����3C[h�� � �,�%$���m)$7� U ����N!�\R7^

�H])�%RA� � R�� � ���/���DNZnB ��fR�� � J$J]Ea � RA��m U � �6[�f[ �����N � $7N#� U ���]����6R*�����"���%R* � � $7N!�,qU � ��%R�N#��N>ne[���K�� ���������� � �������3 � ��3#N! �����]�� R#"�/ � �N# vnr)�6$7����N!�6R "� �� U ��>R*���� � ����N!� � ��R�$J]����D�>R#"� �6[ U � � �D������ � [ �*6R����,�����JR "ia�]���� � U�U �����>[Q��N���� � ��)����3'��]���X �!q � q�X �E�/�6$7N�[�� /^ �H]����� � �������3'[h� � �,�p$�R+NZnOR�� � �6[ � J[ g6� $ � U �N U � 3 � ����N#� "HR*��N�$J] � R*���p$F U [ � ���'" � � �3#���6R "g ��N�$������\$7N�[���)3 (�� � � ���� " �-]�������� U R#"-+ �(�����>R "-X+*,* ��Y%" B��p$ � U �N U " 1 �N�R�R �-���� �N U h � �\[1N!� �*�3 � ��� �B � [�������JRHae�� ��O ��>$7N# J[�f[ � �6[ � � � ��h ���f[Dnr �N!�P ���\RvN>n � �I U [ � ���f[I���� uR���N#�NZn ��]�� ��h U �� U � � ��� � �)��� � ��N! /^

� [N�$S��,������[�fR�$7 �� g ����3"��]��pRHaHN# � a � R U g ���pR�]��>[ ( � � � ���� + �(�����fR#"5X*2* ` � Y " � �\[� � � $�$SN!� U � �h����)3bX � qr�,��������F���%[�/N�a � RA ������ � R*�>[ (�� � � ���� + �(�����>R "HX*2* ` g Y%"ea�]��%$J]] � RBR����6$7� g ����� U � u$c] � R��>[ g hFN>���� � [�N������ $7N!�)���>$7����N!�)�%R��e ��>R*� � u$c])�� JRHaeN! ��p[qra��%[��^

Page 185: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

X � � �e� � � � ����

Page 186: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ������� � ���

� � �� � ����� #���������������� ��!"!$#%�&#('�)+*,#.-/�"�0�1�324�5-6��*��(���879� �:�1'��1�;�<-=#%'0����#&2?>+@+A+����B���0�C�1�;���D�.!$!"EF#.-G��*+�H�����&�I�JA+@��C�K�.��LM�ON

PRQ � � � � Q 9S Q � � � 79�D���J#;LT�������"#(�8�D�<79�TUV�+��7W��#I�1X;���J�<@��1�JYB�1���W�Z�(��� � ����7[�K�%� ���\�5-0>O�]-=�0�1'7+�.�^�._%�`>a�&�CEb�C�0�1�c�D�d�.@b!"�F��#e) ��'C-=#%'0�c�K�%��� � �b#%'��^�.!"!$EO>+@+A+�f*��%�Fgh�b���.'0!"E�i�!"#`�C���*+�H��@+�"!$�"�JE8�0#F)��1'C-=#('����K�%��� �dN

P ��j�k��=l PmQ � � � � Q 9S Q � � � 79#(A+@+!$�W7;�����J#;LT�������$#%�m����79�MU��+��78�0#8��X9�D�C�6�n-G�F7+�.�^�._%�]7&�CEb�Co���1�p*��%�q�87;�����J#;LT�������$#%� Y�*b�1'��1@;E&)��1'J-=#%'��^�.��LT�f#%� �K�%� � � �D�r�$�&)��.�$'���7,�.�V7 �Z�%� ��s���I�+#%'0�m�.!t>uY�*+�$!"�e�.�+#(��*+�1',7b�.�m��_%��7��JE+�J���1�v#.-q�0*+�m�0�.�&�&�JE;)��&79�D�C)+!D�1E+�I��*+�#%)+)�#`�C�"�0�W@��1*��1w;�"#(A+'1x<�K�%��� �y�D�B�"�&)����"'0��7&�.�V7R�Z�(��� � �D�B�+#%'0�m�.!tN

z|{ �Ol9�aS Q � � �q�"wO�1�}��79���J�"'0��7 �5LT#('�'0��LT� �6�m��)+)+�"�b_~-='0#%� ��@��(�C��79#(�m�.�$�y�0#y���K�.'�_(�1�79#%�^�.�"��>��.��7��.���.'0@+�"�0'Z��'�E ��'0A+!"���;�m�.)b)+�"�+_,7;�TU��+��7m#�wO�1'���*+�H�0�.�&�H79#(�m�.�$���T>�����1XbLT�1)+�0�"#%�����I���9E��1!"���&�1�;�|#�-q��*+�&@V�%�C��79#(�m�.�$���0*��.�H���I�m�.)+)���7 ��� �I�M�Z�M� � ���[@;E��*+�?LT#%'0'���LM�|�m��)+)+�$�+_m�.�V7 ��*+�H'�A+!$�F�m�.)+)b�"�+_bN��O�1�?�C��LM���"#(� � N � -=#%'I�����1X;���1��7;��7��'0���.�0�&�1�;�|gt�.��7�L%N�-0N/� l � j��+� iZN

� ��+���ul;�ly� _%'�#(A+)�#.-q#('���*b#%_%'K�.)+*b��L1��!�A+�+�"�K�8g=��N��`N">a!"�1�0���1'K��iq��*V�.�,LT#('�'��]�C)�#%��7b�W��#���C�$�+_%!$�W�J#%A+�V7�>+#%'q)+*+#(�+�1�&�ON/�<X+���&)+!"�]�B�.'0��5���$> ��#%A �$>+�.�V7 ���0* �"N

� � � � ������� �,�"�;wO�1�9�0��7�Y�#%'K7�>+�JA�L�*^�%�r�.�O�9��#%' ���"�M����>9�0*��.�����<�+#(�B)���'��B#�-���*+���G�b_%!"�D�C*!����+_%A���_%�ON �q#%�;YB#%'K7+�<��'��B�JE;)+��L��.!"!$EdA��J��7W��#d�0���C����*b��_%�1�+��'Z�.!$�"�������$#%�W)b'�#%)��1'0���$���u#.-�&#;79�1!D�B��*����|)��1'J-=#%'0�3�^�.)+)+�$�+_O��#%���<�+_%!$���C*�YB#('Z7+�M>a�CA�LZ*��(�r)V�%�C�0oh�0�1���J�F�&#;79�1!D�#%'H���1X;��o=��#(o��J) ����L�*��&#;79�1!D�TNm�B��L1��A��C�,��*b�1E��.'0�&�+#�wO�1!6YB#('Z7+�M><��*+�1E�L��.�+�+#(�F*��1wO�@��1�1�,!"����'��+��7F@;EF���b�1�JYB#%'0�W�0*��.��Y��%�6��'K�.�"�b��7[#(�&�H�C�1�6#�-�)+'�#() ��'B�<�+_(!"�D�C*&Y�#%'Z7b�TN

  �(¡

Page 187: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

  � � ��� � � � ����

� �6l9���9S Q ����� Q� �9S Q �� � �0�1'�� LM#%�&�&#(�+!"EHA��C�]7^�$�m)��CEbL�*b#%!"#(_%EON��6�JE+LZ*+#%!$#%_(��L1��!a�1X9)��1'0o�"�&���9�K�|#.-=�0�1���C���1���0#��m�.�b�")+A+!D�.�0�,�.@��J��'Z�(LT�F#%'F*V�.'Z7;oh�0#%ot79�TU��+���1�;���"�0�"���f�CA�LZ*��%���-=����'���#%'�5��'�#(A�����!��"N��B*+�Fw(�.!"�D79�"�JEm#.-r�.���1X;) ��'��"�e�1�9� 79�1)��1��7b��#(��*b#.Y )+!���A��C�$@+!"E�CA�LZ*I�1�;���"�0�"������'��������M���%�����O�+�%������� �! ���*����u�D�T>1*+#�Y��0*+�1Ef�.'0�B�(LT��AV�.!"!$Ed�"�e)+!"�1�,�1�O�0��7B�"��.���1X9)��1'0�"�&���9��N#"+#%'��1Xb�.�&)b!"�O>O�"����� �1X;)��1'��$�&�1�;�<��#,�&���(�CA+'0�I�C�;�"��LT#(��79A�LT�0�"w;�"�JE#.- �CA+@%$J��LM�Z�u�$�&�I�C�K�.�0�|#�-�-=����'1>O��*+����X9)��1'0�"�&�1�;����'a�&�"_(*9�/L�*b#O#O�C�q��#I#() ��'Z�.�0�"#(���.!$�"�1���-=����'��O�(� �0*+�I�C�K�.�0�d�JA+@%$J��LT�K� ��'��d�$�8Y�*b�1�8�0*+�q�1X9)��1'0�"�&���9�0�1'uAb�+�1X;) �]LT����7;!"EW)�#(�"�;�Z��W_%A+���.�q��*+����N

& �9S�S�l9���('H� Q S�l9� Q �� �B*+� LT#%'0'���LT�0�+���0�uLT'0�"�0�1'��$#%�d-=#%'/LT#%�b�+��LT�0�"#%�b���C���&#;79��!���A��J��7��$�W��*b�����*+�]�C���MN)�B*+����LT'��$���1'0�"#(��Y �%��U�'Z�J�<�JA+_%_(���C�0��7��0#|�e�<@9E �|�1E;�&#%��7+*��D�C����'<�(�u���F�.!$���1'0o���.�0�"wO�I��#e�C�K�.��7b�.'Z7�LM#%'�'0��LT�0�+������LM'��"�0�1'��D�W�JA�L�*��%�d�OA+� #.- �-, AV�.'��]�|�<'�'0#%'�N���*+�1�A��C�$�+_,�W)���������'��mLT'0�"�0�1'��$#%�a>;LT#(�9wO�1'0_%�1�VLT�|#�-<�0*+�d�+���CY�#%'0�.��� ��'K�.�$�+�"�+_H����LT#%���J��79��'���7��#m*��1wO�F@��1�1���(L�*+�$�1wO��7m#%�+!$E �n-H�����M��/W)������0�1'������dLM#%'�'0��LT�dY��$��*+�$����*����FLT'0�"�0�1'��$#%�aN� )��.�0���1'0�����ILT#(���C�D79�1'0��7�LT#%'0'���LM��!"E�!"����'��+�]7 �n-0>�-=#%'?�.!"!/#%A+�0)+A+�Z�I�1!"�DLT�"�0��7R@;E �0*��.�)��.�0���1'0�a>+��*b�W7;��0:�1'�����LT�d@��1�JYB���1�&��*b�W�(LT��AV�.!�#%A+�0)+A+�qw%��!"A+�H����7&��*+�H�Z�.'0_%�1��w(��!"A+����F�J�m�.!$!"�1'I��*V�.�y�0*+�mLT'0�"�0�1'��$#%��w(�.!$A+��gh�$� �0*+���W�0*+���J���T>�19N32 iKN ��*+�1����*+�m)������0�1'��LT'��$���1'0�"#(�W*��(� @��1�1�,�0�.���D� U��]7?-=#('B��!"!+�0'Z���"�+�$�+_I)��.�0���1'0���<�"�F#%�b�|�1)�#;LZ*a>O��*+�q�+�1�JY�#%'��*��%�qLT#(�9wO�1'0_%��7:N

& �)4�4��45 Q�6 �%� P87)9 �hl {�Q ��� �&�"�&)V�.�"'0�&�M�9�<�$�&'��]�%79�$�+_F���1X;����!"#(A�7RY�*+��'��1@;E,�[)V�.���$�1�;�)��1'C-=#('��m�6) #O#('�!$E&#%�m�+#(�9Y�#%'Z7b�T>+@+A+���b#%'��^�.!"!$EF#%�m'���_%A+!D�.'q�.�V7^��X+LT��)+���$#%�&Y�#%'Z7b�� �"����*+�?79A��.!/'�#%Ab���F�(L1LT#(A+�9��> �$�|�D�d�CAb)+)�#O�C�]7 ��*����I�CA�LZ*��F)��.�0�"�1�;�|*V�%�|!$#O�C���%L1LT�]�����#F�0*+�I_%'Z��)+*+�1�e�1oh)b*+#%�+���&�qLT#%'0'����J)�#%��79����LT�I'�A+!$���T>b�.��7m���6'����(79�"�+_e�C#(!"�1!$E8@;E,A��C�#.-/��*+�I!$�1X9�DLT#%��g�L%N -0N;: j���<=� 6 l P>7)9 �=l {�Q � iKN

&?9@7)6 �)4�A45 Q�6 �%� � l-�%� Q S 7 � ��*+��#%'�������L��.!�LT#%�V�C��'0A�LT�H���W7;�1�1�&��7 �0# *��1wO�>�%BC/EDGF��%����)H��DZ�%����0�%���"��/u�n-V��*+���"� .�Ab�1��LT�6#.-V��*����6LT#%�V�C��'0A�LT��#%�F*;A+�m����)��1'J-=#%'0�m�.��LM�BL��.�W@��q79���&#%�+o�C�0'Z�.�0��7��1�&)+�$'��DL1�.!$!"E(NI"+#%'F�1Xb�.�&)b!"�O>��"�W*V�%�F@ ���1� LT!����"�&��7���*V�.�F��*b�R�0*+�1#('��1�0��L1��!79���J���$��LT���$#%�,@��1�JYB�1�1�e'��1_(A+!���'��.�V7^��X+LT��)+���$#%�&Y�#%'Z7b�B*��%�B)��JE+LZ*+#(!"#%_(��L1��!�'0���.!$�"�JEW#(���*+�I@��(�C�D�B#.-6�1X;)��1'��$�&�1�;�Z�<�J*+#�Y��"�+_e�CEb�C�0�1�m������Lq79��0���'��1��LM��� �$�R*b#.Y�-t�%�J�d����7R*b#.Y�%L1LMA+'Z�����1!$E *;A+�m�.�V�|'����(7�'���_%A+!D�.'H�.��7��1XbLT�1)+�0�"#(��YB#%'K7+�8gtL%N�-0N,� l-5�j���+� Q S 7 z <�J

Page 188: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

�;� � � � ����   � 2<Jl 6 S iZN

� l 5�j)�A�b� � �"wO���W�q79���J�"'0��7 �5LM#%'�'0��LT�C�T�m��)+)+�"�b_B-='�#%� �r@��(�C��79#(�m�.�$���0#d�B�K�.'0_%�1�/79#%�^�.�"��>�.��7H�.�?�.'�@b�"��'K�.'0E ��'�A+!$�H�T�^�.)+)+�$�+_q79�TUV�+��7d#�wO�1'a��*+���0�.�&��79#(�m�.�$���T>���'��1_(A+!���'u�$���1����q�.�;Em�1!"�1�e�1�9�6#�-6��*+�H@��%�J�,79#%�^�.�"�m�0*��.�d�D�r�^�.)+)���7 ���9�M�9����DZ�%�"� /?@;Em��*+�?LT#%'0'���LM��m�.)b)+�"�+_?�.��7m��*+�I'0A+!"�I�m��)+)+�"�b_&g�L(N�-0N6z|{)6 l;� S Q 4� iZN

� l 5�j)�A�b� Q S 7�z�� l 6 S�� �y���&)+�"'0��L1��!<��0:��LT�mg�-=#%A+�V7�>��"����*+�D�FL1�%�J�O>B�$� '0���%7;�"�+_��C�0A�79�"�]��i��*����I�C*b#.Yq�I�&�JE+�J���1�^�.���DLI79��0:�1'0�1��LT�I�"��)��1'J-=#%'0�m�.��LM�W#%��'0�1_%Ab!��.'��.��7 �1XbLT�1)b���"#(��"�0�1�m�TN �B*b���F��0:��LT�,���WA��JA��.!$!"E LT�"�0��7��%�,�CA+)b) #('��&-=#%',��*b�1#%'0�"���W�0*��.�mLM!��.�$� �0*��.�'��1_(A+!���'q�.��7m�1XbLT�1)+�0�"#%�e�"�����m�6�.'��H)+'�#;LM�����J��7m79��0:�1'0�1�9�0!"E,@9Ee*9A+�^�.���MN

: j���<=� 6 l P>7)9 �=l {�Q �y� ���"�e)��.�$'��&�M�9���$��'0���%7;�"�+_m����X9�H�.!$#%A�7�Y�*+�1'0�1@;E��^)V�.���$�1�;��)��1'0o-=#%'0�m�d) #O#('�!$E�#%����X+LT��)+���$#%��YB#%'K7+�T>6@+A+�H�+#%'0�m�.!$!"E�#%��'��1_(A+!���'WY�#%'Z7b�W�.�V7\�b#%�+oYB#('Z7+�@ �$�R�0*+�F7;A��.!�'�#(A+���?�%L1LT#(A+�;�1>+�"���D�|�JA+)+)�#O�J��7 ��*V�.�f�CA�LZ*��F)��.�0�"�1�;��*��(�|!"#`�C��%L1LM��������#&�0*+�W�$�9�0�1'��V�.!a!"��X9�DLT#%�a>b�.��7 �D�r'0���%7;�"�+_m�J#%!$�1!"E&@;EmA��C�H#.-6�0*+� � ��� '�A+!$���g�L%N -0N & �)4 �)4�A45 Q�6 �%� P>7)9 �=l {�Q � iKN

Page 189: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

  ��� ��� � � � ����

Page 190: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

� ��� � � � � ��� �v�

� !"!$�1�a>��+N">�|A+�+�+�DLTA+�0�1> '�N$>���d!������1> WNBg  ������ iKN��a� ���c�C� ,��I��� B=���Z� DGF����.F�� ����b�%���BC/ BM�J���WN �����8@b'���7;_%���J��A�7;�"���a�"�,�J) ����L�*?��LT�$�1��LT������78LM#%�&�,A+�+�$L1�����"#(�aN �����8@b'���7;_%�O>' � x �����8@b'���7;_%���|�b�"wO�1'K�C�"�JE��G'0�����MN

� ��79'0�1Yq�T>I��NIg  ���� �;iZN ��*V�.��LT#%�b�+��LT�0�"#%�b���C�m�&#;7;�1!��,L1�.� g�����7 L1���+�+#(�Ti,���1!$!dA��MN ����+N ���$!"���M> �qN *a�.���$�&�1'�>! �qNu�O�0�1wO�1���Ig��67+�MNniZ>#"��%�"�"� DT�J� �%$ �����M� B ��� �����'& /(�����

BC�*)+� �O��"��O�+� � DT�����O�%��BM� � �9�Z� BF�O� �,$�BC/!DGF��%����)H/�>+)+)aN�- �/. ¡ 19N#�B*b�0�|�+�$wO�1'Z�J�"�JEF#.- qA+�1�1���J!�����7�> � A��C�0'Z�.!$���;x��6#%�&)+Ab���1'd�;LM�"�1��LM�1 |��)��.'0���&�1�;�1N � �]L�*aN �r��)aN�- ��� N

� �+������7+�.!$�O> �qNag  2�(� 1 iZN43 ���8� BM�5) �H/ �H��DM�����O�+�O�@/.N����1���1'6�f�%7+79#;LZ� *��K7�N

���.�;�O�1'1>��Nug  ��(� - iKN� |#%�#� �IL1��'��W�^�.'�_(�"����*+�1!$) @��(L��;)+'0#%)���_O�.�0�"#(��!"����'�� ��X+LT��)+���$#%���MN7���� N � 7+���m�8 *<N��`���1'0!"�"�b_8gt�67+�TN5iZ>9$ � � DT�Z� �H��� ) B+� �f��F���:%��F8�;)!BM���0�%�����O�%<��H���9�4"��O�

����M�����%DT� �O�R�f����� =�D����%�!���9�J�Z�"��� );�M�%D1�Z>�)+)aN  �¡(� .   � �+N<�O�$�+_O��) #('��Ox ��#%'�!D7 �;LT�"���9�0�nU:L%N���.�;�O�1'1> �uNIg  ��(� �9iKN � #O#;7 �&#;7;�1!��8#�-F*;A+�,@+!"�m#%'0�"_(�"���MN>���?�+N ���"!"�]�T> �qN *a�����"�e�1'1>

�qNu�O�0�1wO�1���Hg��67+�TN5iZ>6"��%�"�$� DT�C� �@$������M� B ��� ���c�'& /(����� BC�*)A� �O�B"��O�+��� DT�����O����BM� � �9�Z� B��O� �C$�BC/!D F��%����)H/.>B)b)aN   1�-D.   1 �bN �B*+�E�|�+�$wO�1'Z�J�"�JE�#�- qA+�1�1�V�C!�����7�> � A��Jo��'K�.!"�D�9x��6#(�&)+A+�0�1'|�;LM�"�1��LM�� |�1)���'��0�&�1�;�1N)� �]L�*aN �r��)aN�- ��� N

���.�;�O�1'1>H��N">�*����C�0�1'1> �IN">F ���$!"���M>��+N�g  ����%¡ iKN6�<X+LT��)+���$#%�,!"����'��+�$�+_W@;EF@��%LZ�;)+'�#()��._`�.���$#%�ax� �+�1Y��1'0'�#%'�-=Ab��LT���$#%�aNG� � �uN�*��1#(�+_1 '�N��O��@+'���gt� 7b�TNniK>�$ � � DT�Z� �H��� ) B�� �6��F�� � ��)9�Z� F�;) BM�t���%� ���O��"��O� ���M�����%DT� �O� �H��)9�0�%� �H�Z�IH �O����BM>�)+)aN  % 2� .   -   N �OEb79�+��EO> � A��C�0'Z�.!$���;x�OEb79�+�1EJ�q�+�"wO�1'K�C�$�CE?�<!"��LT�0'��DL1�.!��G�b_%�"�b�1�1'��$�+_+N

���.�;�O�1'1>-�uN$>-�G*b�"!"!$�")��M>+��N">F ���$!"���M>A�+N�g  2�(� �9iZN��B*b�   1E1!1.oI-.o   1E1H18�1��LM#;79�1'1x � �m�.�0���1'6#.-'��1)b'����J�1�9�K�.�0�"#%��N �H��)9�0�%� �W�K�5H �O���LK �O�Z� �%>NMBg�2 iK>2(- � .-2 ¡ �+N

  ���

Page 191: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

  �(� ���$� � � � ������ � �

���.�;�O�1'1> �uN$>6 ���"!$���T>;�+N�g  ����%¡ �OiZN � � �.�+�$�m�.�0��7��C�0A�79E #.-F!$���.'0�+�"�b_y7;E9�����&��L��8�"���*+�   �%oI-.o   � �1��LM#;79�1'1N � ��LZ*aN ���1)aN6- � �+>0 |��)��.'0���&�1�;�&#�- �6#(�&)+A+�0�1'��;LT�"����LT�O>�B*+�0�q�+�"wO�1'K�C�$�CE,#.- qA+�1�����C!D�.��7�> � A��J��'K�.!"�D�9N � w(�.�"!D�.@+!$�I@9E��.�b#%�;E9�&#(A��r-=�0)R-='�#(�-=��)aN�L1�TN A,�N�#%�`N��.A�g��1)bA+@�������� � �q����� � �|����79��)��.'0���&�1�;��� � ��1�- � �+N�)V�TN�aiKN

���.�;�O�1'1> �uN$>! ���"!$���T> �+N/g  ����%¡ @�iZN � ���.�+�$�m�.�0��7 �J��A�79E�#.- !"����'��+�$�+_m79E;���.�e��L1�B�$����*+�  �(o5-�o   �y�1��LM#;79�1'��w;��79�1# ��N �   2.o=�&�"�;A+�0� ���+�"�^�.���]7 w;��79�1#bN � w(�.�$!��.@b!"� @;E�#%'K79�1'-='�#(� �0*+�' q�1)��.'0���&���9�I#.- �6#(�&)+A+�0�1'F�;LT�$�1��LT�O>)�B*+� �|�+�"wO��'Z�C�$�JER#�- qA+�1�1���J!�����7�> qA+�1�1���J!�����7 �H1 � -9> � A��J��'Z��!"�D�9N

���.'�#(�a>��+N$>�3�O��'K�1Yq�C#%��>��qNBg  2��� � iZN �d�J�8#�-q#%'��0*+#%_('Z��)+*+��Le�.��7�Y�#%'K79o��J)���LT�nU L8�9�b#.Y�!$o��79_(�8�$��'0���%79�$�+_ Y�#%'K7+�W��!"#%AV7�NC<���);�T�+�%� � � +-, ���M�@�*�8�M�9�t�%��$ BC/EDGF��%����)H/��,3 )A�F�O�$q�M� DT���������O� �O� � $q�M� �C�O���F�O�%DT�Z>��<g ¡ iZ> ¡���� . ¡(�(¡ N

���.A+�1'�>A WN �4N$>Ns�O�Z���+#�w9�DL�*�>+�FN;��N�g  ��(� 1 iKN�*��1X9�DL1�.!:�(L1LT���0�B�.�V7^�0*+�I�J) ��!"!"�$�+_%o=��#(o��J#%A+�V7'��1_(A+!���'��$�CE,��0:��LT��N ���� �O�@/��>"���)O�%�"�����O�9>��ug�2 iZ> �G- � . � ¡ -9N

���.A+��>���NO�dN$> ���$!�LT���1��>C"BN;g  ������ iZNa�OA+)��1'�w;���J��7�!$���.'0�+�"�b_d#.-�)b'�#%@V�.@+�$!"�"�JEH79�D�C��'0�"@+Ab���"#(���@9EF�b�1A+'Z��!��+���CY�#%'0�+�MN ���J HN���N � ��79��'Z�C#(��g��67�N5iZ> �W��);���%�N��� �C�O� �F�%�����O� $ � ��DT� B BC��� )& / BM�J���?BM>+)+)�N2(-D. �9  N �|�1Y 6#%'0��x � �&�1'��DL1�.� �����C�0�"�0A+���I#.- �<*9Eb�C�DL1�TN

�B���.A+wO#(���M> '�N-"BN">� ����'�#%A�����C�+�`>+�+N�g  ����D� iKN �<*+#%�b#%!"#(_%�DL1�.!��.!"��X9�D�9x �B*b'��1�f79���0�C#;LT�D�.�0�"#%�V�TN<%��);�M�+�%�#� � �H��);� �%����)H/�� �W��);� � B2);� );�M��/F�O� � $�BC/EDGF����%���@/.>FM��O>  ( %  2�.  (  - ��N

�B��L��O��'1>���N$> *�� �6A+��> FN<g  ����(� iKN'���&)+'0#�w9�$�+_8�0*+�,LT#(�9wO�1'0_%�1�VLT�W#�-�@��(L��;oh)b'�#%)V�._O�����$#%�!"����'��+�$�+_&Y��$��*��C�]LT#%��7�#%'K79�1'd�e�1��*+#;7b�TN � �E HN#� #(A+'������1�;EO> � N �|�$�9�0#%�a> �dNu�`�1o$J�+#�Yq�C�;��g��67+�MNniZ>�$ � ��DT�Z� �H��� ) B � �B��F���� ����� "��O�+� � DT�����O�%��BM� � �9�Z� B8& )A�0�8�M��& DGF����%��>)+)aN�- � . ¡�� Nu� �.� '��.�0�1#+> � � x ' #('�_`�.�@�I��A9-=�m�.�b�aN

�B�1*+'��^�.�+�a> '�N">� �BA+@a>� WN/g  ���� -OiZN��`A+'C-t�(LT�F79Eb�C!$�1X;���F�.�V7�79E+�J_%'K�.)+*+�D�9x6 |A���!<'�#(A+���]�T>�C�$�+_%!$��!$�1X;��LT#(�aN6"�� )`�%�"���������H��);� ���%BC/!D F��%����)H/.> �ug ¡ iZ>�-!1 � .�-!2   N

�B���C�+��'1>� WN$>H�BY��"!$!"�1E`>!*<N$> '�L ���.�b�a> ��N9�VN">� �O�1�1'0_%#(@+�"�a>G�[Nbg  ���� 1OiZN!�q�,��*+�q�(���C#;LM���.�0�"#(�@��1�JYB�1�1�^LT#%�+�b��LT���$#%�+�D�C�p�.��7m7+���Z�;x � '0�I�W-=�1Y Y�#%'K7+�B�+��LT�]������'�E#"�$�BC/!D F��%����)H��DZ�%�(d�$�C�h��Hu>���%�g ¡ iZ> � ¡ -�. � � � N

Page 192: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �   �(��BA+!"!$�"����'����;>A�+N � N:g  ���� �;iZN8���9�0�1'��V�.!�'0�1)+'0���C�1�;�Z�����$#%���6#.-G�FLT#%�+�b��LT���$#%�+�D�C���&#;79�1!:#.-/'����(79o

�"�+_���!"#%AV7�N'��� � N �q�.� >�FNa�<���J�1!"�,gt� 7b�TNniK>�$�� ��DT�Z� �H��� ) B � �,��F�� & � ,]�C�Z�M�;� F��f� ��N);�%�7"��O� ���M���M��DT� � �,��F���"���)O���"�����.� & D��h�M��DT� & ��D��h�Z��/.><)b)aN � �/. �(� N8�|�"!$!���7b�.!"�`> �;�+x*a�1Y�'��1��LM�W�<'0!"@���A+� � �0�C#;LT�D�.���]�TN

�BA+!"!$�"����'����;>4�+N � N"> �6*V�.����'1> �HN|g  ��(�(¡ iKN |#%Ab@+!"��79�D���J#;LT�������"#(���"� ��'����5U:LT�D�.!q�+�1A+'K�.!�+�1�JYB#('��b�Tx6���&)+!$��L1�����"#(��� -=#%'f�+�1A+'0#%)��JE+LZ*+#%!$#%_(EON ����$ � ��DT�Z� �H��� )�B � �?� F�� ��� �M�J�Z�M�9��F�f�+�N);�%�4"��O� ���M�Z�M�%DT� � �?� F�� "���)O�%�"�����.� & DC�h�M�%DT�0& ��D��h�Z��/.>�)b)aN - �(¡ .�- �(� N��|�$!"!D��7+��!"�O>�1�+x%*a�1Y�'0�1��LT�H�<'�!$@��.A+� � �0�C#;LT�D�.�0���TN

�BE9@��1�O> �+N#*<N$> 3�O!$#%@+�$�a> WN �ZN<g  ���� - iKN �rA+!$���d����7��0L�*b�1�m�%���"���0*+�,79�1wO��!"#%)b�&�1�;���.�V7A��C�I#�-6��*+�H�<�+_(!"���J*m)��%�J�|�0�1���C�`N����O� )�);� )9�Z>�:���g   oI- iK>!- � 2�.A- ��� N

�6*+#%�m�J�9E`> �WN:g  ���� 1OiZN (;)O�"� BH�O� �R�Z���:��� B��M�9�t�%�����O� BMN��qXO-=#%'K7�xB���(�C�$!a�B!��(L��;YB��!"!�N�6*+#%�m�J�9E`> �WN$> �f�.!"!$�O> '�N9g  ������ iKN7�.F���BC��)9� ���+�%�=�J�M�T� � � + � )(����B F;N �q�1Y 6#%'0��x��d��'�)��1'

��#�YIN

�6#%!"�0*+����'��1>-'�N6g  ����D� iKN *��1X;��L1��!��%L1LT�]�����$���C�$�&)+!$�F'����(79�"�+_��Z�(�C�b�TNE��� � N��|��7;�1'�Y�#O#;7g��67�N5iZ> &����0�%�C�*) �h� B�� � ��� �C�O���F�%�����O� �:� ��DT� B BC��� )%>+)+)�N   2   .�-   � N *�#(��79#(�ax � L��%79�1�e��L�<'����0�TN

�6#%!"�0*+����'��1>�'�NIg  ��(� 1 iKN �r�]�%79�$�+_+>d)+*b#%�+#(!"#%_(��L1��!W'0��LT#;79�$�+_+>H�.��7 79�1�1) 79Eb�C!"��X9�D�9N>���'�N��6#%!$��*+�]�.'���>��FN��/�.���0�1'Z�J#%�a>� �+N �qN '���'Z�C*V�.!"!,gt� 7b�TNniK>)�F�Z��� �H/ BM�"� , ���%>d)+)aN ���� .A-�- � N#*�#%��7;#%�ax ��#%Ab��!"�]79_%� �d�1_`�.� �<�.A+!tN

�6#%!"�0*+����'��1> '�NIg  2�(� �`� iKN �6#%�+�b��LT���$#%�+�D�C���&#;79�1!$!"�"�b_��.��7 LT#%_(�+�"�0�"wO��)��CEbL�*b#%!"#(_%EON�����+N ���"!$���T> �qN;*a�����$�&�1'1>8 �qNB�`���1wO�1�V�&g��67+�TN5iZ>0"��%�$�"� DT�J� �L$ �����M� B���� ���v�C& /(�

��� BC�*)+� �O� "��O�+� � DM�����O�%��BM� � �9�Z� BF�O� � $�BC/!DGF��%� � ) /.>�)+)aN  �� .�- ¡ N�B*b� �|�+�"wO��'Z�C�$�JE#.- qA+�1�1���J!�����7�> � A��J��'K�.!"�D�9x��6#(�&)+A+�0�1'|�;LM�"�1��LM�� |�1)���'��0�&�1�;�1N �a��LZ*aN ���1)aNF- ��� N

�6#%!"�0*+����'��1> '�N<g  ���� �%@:iZN �6#(�+�+��LM���"#(�+���J�d�&#;79��!"!"�$�+_e�.��7�LM#%_%�b�"���$wO�W)��JE+LZ*+#(!"#%_(EON �6#(�&o�&�1�;�Z�u�^�%79�f79A+'0�"�+_?�W)+'����J�1�;�Z�.�0�"#(�m�.� �[�OE;�&)�#O�J�"A+� #(� �6#(�+�+��LM���"#(�+���J� ' #;79��!���.��7 �6�CEbL�*+#(!"#(_%EO>F�O�.�;A��.'0E  2�(� �+>:�B'����J@��.�b�O> � A��J��'Z��!"�D�9N

Page 193: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

 /� 1 ���$� � � � ������ � �

�6#%!"�0*+����'��1> '�N$>u�B�]�C�+�1'�>� WN">��%#%�V�%���J#%�a>8�+N)�dN$> d�1wO�1!��(�.'1>���N6g  2��� � iZN �<*+#(�+#%!$#%_%�DL1�.!�1��LT#;7;�"�+_��"� ��*b��!$�1X9�DL1�.!f79��LM���C�$#%� �Z�(�C�:N � );�O���J�M�Z��/ <���);�T�+�%��� � +-, ���M�@�*�8�M�9�t�%�$�BC/!DGF��%����)H/�>�� ��> � �(� . 2!1 � N

�6#%!"�0*+����'��1> '�N"> �6A+'0���D�T>O�dN$> � ���;�"���M>!��N">� �d��!"!"��'1> '�N;g  ����%¡ iZN�' #;79��!��u#�-�'0���%7;�"�+_I��!"#(A�7�x |A���!�'�#(A+���f�.�V78)��.'K�.!$!"�1!$o�79�D�C�0'��"@bA+����7;oh)+'0#;LT���0�C�"�b_F�.)b)+'�#`�%LZ*+���TN�$�BC/!D F��%����)H��DZ�%� (d�

���h��Hu> �����ag �9iZ>�2 ��� . � 1 � N

�6#%���0'��1!$!�> � N �4N"> �<!"Ab�+�O�1����>8�FNBg  2�(�;  iZN *�����'��+�$�+_��0*+�m)��%�J�F���1�V�C�m�"� � '��]LTA+'�'0�1�;��+�1�JYB#('��:x � LC, A+�$'��$�+_d��*b�|�m��)+)+�$�+_d-='�#%� �e���.�+�$�+_O�<�0#F�C#(A+��7+�MN�� �J$ � ��DT�Z� �H��� ) B�� �� F��J�.F����Z�J�Z�M�9��F&�f�+�N);�%� "���)O���"�����.�1& D��h�M�%DT� "��O� ���M�Z�M�%DT�Z>�)+)aN ¡ - � . ¡%¡(¡ N �|�$!"!D��7+��!"�O>�1�+x%*a�1Y�'0�1��LT�H�<'�!$@��.A+� � �0�C#;LT�D�.�0���TN

d�.A+_(*+�1'0�CE`>��[N$>N �O�1��7;�1�9@��1'0_+> '�N���Nag  2�(� -OiZN ��A+!$���B#%'qLT#(�+�+��LM���"#(��� " �B*b��)V�%�C�q�������C�'��1w;���J�"�0��7�N ���0$�� ��DT�Z� �H��� ) B � �B��F�� � ��)9�Z�J�Z�M�9��F��f�b�N)9�%� "��O� ���M�Z�M�%DT��� ����F��6"�� )`�%�"�������& D��h�M��DT� & ��D��h�K��/�>+)+)aN�-!2 � .�- � �bN��|�"!$!���7b�.!"�`> �;�+x%*a�1Y�'��1�VLT�H�G'0!"@���A+� � ���J#;LT���������MN

|�1�+�+�D�T>O��N"> �<*+�$!"!$�")��M>%��NOg  2�(�9  iZN � ���.!$E+�J�����0#O#%!��a-=#%'��+�1A+'K�.!O�+�1�JY�#%'��b�TN-�a��LZ*aN ���1)aN -E1 � > |�1)���'��0�&�1�;� #�- �6#%�e)+A+����'|�;LT�$�1��LT�`>%�B*+� �|�+�$wO�1'Z�J�"�JEW#�- qA+�1�1�V�C!�����7�> � AV�C��'K�.!$���9N

|�"_(�"�Z��!���,OA+�")+�e�1�9� �6#('�)�#%'K�.���$#%� g  ��(� 2 iKN d���6�Z��!"� �6#%�&)bA+���1' )+'�#(_%'K�.� �tN ���6o�1   o �d� N

�G!$�m�.��>N�+N%*<N�g  2�(� 1 iZN�"u�$��79�"�b_,�C��'0A�LT�0A+'��I�"�m�0�"�&�ON6"���)O�%�"�����.�1& DC�h�M�%DT�Z>���M+>   � � .A-  (  N�G!$�m�.��>8�+NBg  2�(��� iZN �r�1)b'����J�1�9�K�.�0�"#%�\�.��7 �C��'0A�LT�0A+'��m�"� LT#(�+�+��LM���"#(�+���J�W�&#;7;�1!��MN �a��L�*�N

�r��)aN � � * �(� 1 ¡ > �6�1�;����'u-=#%' �����C����'ZLZ*8�$� *a�.�+_(A��._(�O>��|�+�$wO�1'Z�J�"�JEI#.- ���.!"�5-=#%'0�+���H�.��;�.� |�"��_%#+N

" ��*+!"�^�.�a>���Nag  2�(�(� iZN "��(�C����'�o=!"����'��+�$�+_Fw(�.'��D�.�0�"#%�V�r#(� @��(L��;oh)b'�#%)V�._O�����$#%�ax � �R���&)+�"'0��L1��!�C�0A�79EONE��� WN��a#%A+'0�1�����9EO> � N8�|�"�;��#(�a>� �dN �O� $J�b#.Yq�J�9�fg��67+�MNniZ>4$ � ��DT�Z� �H��� ) B � �� F�� � �����C"��O�b� � DT�����O�%��BM� � �9�Z� B & )A�0�8�M� & DGF����%��>:)+)aN ¡�� .-2   N6�;�.�'������1#b> � � x' #%'0_O�.� �I�.A9-=�m���+�aN

Page 194: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �  /�O " ��*+!"�^�.�a>9�VNO��N">A *��1@+�$�1'��`> �qNH*<N�g  2�(� 1OiZN)�B*+�fL1�%�0L1�%7;�1o�LM#%'�'0�1!������$#%�,!"����'��+�$�+_H�.'ZLZ*+�$����LTo

��A+'0�ON����E WNu��N � #(A+'��1�0�1�;E�g��67�N5iZ>u� ���1�O�%DT� B ��� �H��)9�0�%� ��� �C�O���F�%�����O��$ � ��DT� B BC��� )& / BM�J���?B �O>9)�N2(- �bN � �.� '������1#b> � � x ' #%'0_O���@�I�.A9-=�^�.�+�aN

" ��'Z��*a> '�NN�+N$> � � �r�1�$!"!$EO> �IN �qN">F�� �]LT�1'Z�;> ��N��uN:g  ����%¡ iZN |���0�C#;LT�D�.���]78#�wO�1'�� �.��7mLT#�wO�1'0�'���LM#%_%�b�"���$#%�e�%���.�&�1�e�1'�_(�1�9��)+'0#%)��1'��JEF#�-/��!$���C�$#%�+�]7[�+��A+'Z��! �b�1�JYB#%'0��N $�BC/!DGF��%� � )

��DZ�%� (f�$���h��Hu> �����ag �9iZ>2 �O  .-2 ��� N"V#;7;#%'1>��+N � N">A �GE;!"Eb�C*;E;�a>���N�g  2�(��� iZN �6#%�b�+��LT�0�"#%�b���C�p�.�V7RLM#%_%�b�"���$wO�d��'ZLZ*+�"�0��LT�0A+'��Ox �

LT'��$���DL1�.!:�.�V�.!"Eb�C�D�TN "���)O�%�"�����O�9>�� �%> ¡ . �O  N"V#('Z�J���1'�>+�FN��ZN$>� �6*����8@��1'K�T>9��N '�N g  �����¡ iKN#*��1X;��L1��!��%L�LT�����6����78�����&�"�+_f���"�e�ON!<���)9�M�+�%�

� ��� �M���Z�%� �<�0�O�M�%��� )e�O� ��� �M���Z�%��2d� Fb���C����)9�Z> � �O> � - � . �(¡ 2;N

"V'K�.��LM���T> �4N �WN$>( �dA��LT�1'K�9>��HN g  ���� - iKN �a�Z��)+�M�%D�/F�O�+�%� / BC��B � � +�� )%����B F )!B�� )9���B�$� ,E��D �O��O� � )O�0���0�F�O��N/�B#O�J��#%��x �|#(A+_%*;��#(� ' ���&�$�aN

"VAb�+�+�1!$!�>O��N+g  ��(�(¡ iKN�<*+#(�+#%!$#%_(��L1��!�)+'0#;LT�����J���<�"�,'����(79�"�b_+x �q�1Yy�1w;��7;�1��LT�6-='�#%� �(L�,OA+�"'0��779Eb�C!"��X9�D�9N 2r���"����B FJ<���)9�M�+�%�)� �1$�BC/EDGF��%����)H/.> % M+>   2 � .  2� 1;N

� �$!"���M> �qN*<N$>N �q�&!$�"�a> �qN �4Nag  ����%¡ iZN �rA+!$�I'��TU��b�1�&�1�;�<Y��"�0*m'���LTAb'�'����9���+�1�JYB#('��b�TN����� +-+-+B���9�C���T�+�%�����O�+�%�8"��O� �������M�%DT� �O� �W� )9�0�%� �H�Z�5H �O�K��BM>+)�N �9  19N�<���0L1�.�K�1Y��1EO> �;�+x�J� �6� �G'0�����MN

� !$A��C*b�O#+> �INN�+N:g  2��� � iZN��B*+�f#%'�_`�.�+�$���.�0�"#(� ����7m�%LT�0�"w(�.�0�"#(�R#�-�#%'0��*+#(_%'Z��)+*+�DL��;�+#�Y�!"�]79_%��"��'0���%7;�"�+_���!"#%AV7�NB<���)9�M�+�%� � � +-, ���M�@�*�8�M�9�t�%� $�BC/!DGF��%����)H/��%3 )A�F�O�L$q�M� DT���������O��O� �,$q�M� �C�O� �F�O��DT�Z>�:ug �;iZ> ��� �/. �(�;  N

� #('��m���a> ��N �uN$>! �O� $J�+#�Yq�C�;��> �dN �+Nug  ����(� iKN+*����.'0�+��7�LT!D�%�0�C�nU L1�.�0�"#%��#�- �C#%�V�.'d�K�.'�_(�1�Z�A��C�$�+_,�F�m�%�0�C�"wO��!"EW)V�.'Z��!"!$�1!a�+�1�JYB#('��:N � +$+-+ �b���O� B��HDM�����O� B��O�R� D ��) BM����DGB ��&H���Z� DGF�O� �,& � )`�+�%� $ � � DT� B BC��� )%> �� ag � iZ>  % �¡ 2D.  %  �-19N

�d�.!$!"�O>-'�N$>� ' #(*��.�V�.�a>4�FN �uN�g  2�(� 2 iZN �O�1_%�e�1�9�K�.!6)+*+#(�+#%!$#%_(E #�-I�&#;79��'����<�+_(!"���J*aN����� )�) ��BM����D �M���) ���@/.> �� �g   iK>2 � .  %  � N

Page 195: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

 /� - ���$� � � � ������ � �

�d�.���J#%�a>+��N��+N">���BA+'0'1>� WNG�+N9g  ��(� 1 iKN ��*����6LT#(�+�+��LT�0�"#(�+���J�u�&#;7;�1!��a!"����'��axa!$���.'0�+�"�+_f�.�V7'��1)b'����J�1�9�K�.�0�"#%�H�"�?LT#%�+�b��LT���$#%�+�D�C�a�+���CY�#%'0�+�MN �.F��62d� Fb�������O�0�%�+�O� ��2q�0�H��� & D��h�M�%DT� BM>� �%> � �O  . 2  2� N

�d�.'0�O> '�N$>���<!"�^�.�a> �+N�*<N;gh�$��)b'����0��iZN�*����.'0�+�"�b_d����7��&#('�)+*b#%!"#(_%�DL1�.!;LZ*��.�b_%�ON�"���)O�%�"�����O�9N�|�1��79��'Z�C#(�a>-*<N�g  ��(� - iKN � �Z� F���)O�0���%F�/W�O� � H �O� �8�Z� D � )`�%�"�����O� ��� ���0� �H��� )%N#*�#%�V79#%�ax � L1��o

79�1�&�DL��<'0�����MN

�|�"�;��#(�a> � N���NBg  2�(� � iZN *����.'0�+�"�+_�7;���C�0'��$@+A+���]7~'0�1)+'��]�C�1�;�Z�����"#(����#�-fLT#%�VLT�1)+�K�TN � � $ � ��

DT�Z� �H��� ) B8� �&��F���+ � ) F;� F��f�+�N);�%�1"��O� ���M���M��DT� � �,��F���"���)O���"�����.� & D��h�M��DT�'& ��D��h�Z��/.>)+)aN   .   -;N!�q�"!"!D��7+��!"�O> �1�+x*a�1Y�'0�1��LT�H�<'�!$@��.A+� � ���J#;LT���������MN

�|�"�;��#(�a> � Na��N"> �`� $J�+#�Yq�C�;��>#�dN �+N<g  2�(��� iZN *�����'��+�$�+_��.��7�'��1!$���.'0�+�"�b_&�"���B#(!"�����m�.�+��m�%LZ*+�$�+���TNF��� WN;�rN �rA+�e�1!"*���'��?�+NH*<N '�L �6!$�1!"!D�.��7,g��67+�TN5iZ>N$ �O���%�$�"�Z� �H��BM���@� ��)O�C� ��:� ��DT� B BC��� )A�$+-, �����O�0�%�����O�HB����R��F��1� ��D�� � BM�t� )-DT�I)9�Z� � ��D ��)O�%�"�����O��� �%�%� )A�8� ��� � ��)9�

�O�%�����O�HBMN ���.�,@+'��D79_%�O> ' � x '@�=�(�<'��]���TN

�|�"�;��#(�a> � N(��N"> �O*���!"!$��LT�O>��dN;g  2�(�;  iZN*��]�C�"#(�+�"�b_I�.�?�.���0'Z�(LT��#('<�+�1�JYB#('��:x�� �;wO���J���"_`�.�0�"#%�V�#.-G�%L�,OA+�$'���7m79Eb�C!$�1X9�D�9N8$ BC/EDGF��%����)H��DZ�%� (f�$���h��Hu>�����g   iK> � � . � 2;N

�|#%'0�+�"�:>(�FN$> �O�0�"��LZ*�LT#(�8@��O>�'�N">����*+�"�0�O>��WNOg  ����(� iKN ' A+!"�0�"!D�]EO��' -=�1��7O-=#%'�Y �.'K7��+�1�JY�#%'��b��.'0��Ab�+�"wO�1'K����!a�.)b)+'�#�X;�"�m����#%'K�TN �H��);���%� �H�Z�5H �O�K��BM>��O> ¡ 2 � . ¡�� � N

�%#%*��������J#%�a>6��N">� |#�Y�!D�9>)"BN"> � #O#;79�m�.��>� WN<g  ����9  iKNm���%LZ�9)b'�#%)V�._O�����$#%��!"����'��+�$�+_&-=#%'�8Ab!"���$!��1E%��'V-=����79o�-=#%'�Y �.'K7��b�1A+'Z��!9�b�1�JYB#%'0�+��AV�C�"�b_|�0*+��LT#%�!$JAb_O�.�0��_%'K�%79�$�1�9�a�e�1��*+#;7:N�M�9�J�M�M�+�%�����O�+�%� <���);�T�+�%� � � �H��)9�0�%�!& / BM�J���?BM>��<g �9iK>�- �9  N

���$�&#%�0#+>-�dN">F � �0�.�(�1Y��;>N�FN�g  ��(� 1 iKNr�O�0#;L��,�m��'��O�1�6)+'0��79��LM���"#(�m�CEb�C�0�1� Y��"��*e�&#;79A+!D�.'�+�1A+'K�.!q�+�1�JYB#('��b�TN � � $ � ��DT�Z� �H��� ) B � ��� F��J�M�;�C�M�M�+�%�����O�+�%�6<%�H���9�J"��O� ���M���M��DT�I�O��W� )9�0�%� �H�Z�IH �O����B ��&:�O��� �h�*)H�%>O)+)�N   . � N � �+� � '�@�#%'�> '@�Zx��J�6�6� �|�1A+'K�.! �|�1�JY�#%'���6#%A+�VLT�"!tN

��'0A+_%!$E;�.�:>-*<N g  ���� 1 iKN��|#�Y ��#F�J#%!$wO�|�0*+� ��@+�$� ����LT#;79�1'�)+'�#(@+!"��� Y��"��*+$JA��J�B�JYB#I*+�D7+79�1�A+�+�$�Z�TN �H��);���%�8"������ )O���%�����O�9>��<g �9iK> ¡(��� . �H1   N

Page 196: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �  /��¡*a�]wO#('��1!t>)�uN�'�N6g  2�(�(¡ iZN �<'0#;79A�LT�0�"#%�\�C��'K�.�0�1_%�$���Tx � �CEb�C�0�1�m�d��)+)+'�#`�%LZ*���# ���1'��b��LZ�O�H���

�.)+*V�%�C�D�9N8����'�N � N � '0@+�"@�>+ HN ���.)b!��.��>� �+N �qN '��.'K�C*���!"!6g��67+�MNniK> �H��)9�0�%� � � �9�Z� B� �I�5�O� )G)9� )9���:� ��DT� B B�� BM>O)+)aN  �¡ 2�.  /�`  N �|�1Y 6#%'0��x � L1�%7;�1�&��L(N

*��"�+_b> �qN��FNdg  ��(� �O�OiZN *�����'��+�$�+_���*+��)��%�J�m���1���J��#�-,�<�+_(!"���J* wO��'�@��Mx �B*+���CE;�8@�#(!"��L)��.�0���1'0�m�%�0�C#;LT�D�.�0#%'�wb�TN;LT#%�b�+��LT�0�"#%�b���C���&#;79�1!D�TN�<%��);�M�+�%� � �|�f�Z��� = D����%�9���9�C�K�"��� )9��� DT�(d� B��0�O� DGF;>���>�-!1 � .A-�- � N

*��"�+_b> �qN��FNBg  ��(� �%@�iKN �<'��]79��LT�0�"�+_��"'0'��1_(A+!���'W)��(�C�,���1���J���Tx �6#(�&)��.'0�"�+_��JE9�,@�#%!$��LF�.�V7LT#%�b�+��LT�0�"#%�b���C�/�&#;79�1!D� ��_O���"���J�B�������"wO�f�<�+_%!$���J*&�J) �]�.�O�1'K�TN ��� � N �q�.� ?�FN9�<�D�C�1!$�g��67+�MNniZ> �.F�� & � ,��C�Z���9� F �f�+�N);�%��"��O� ���M�Z�M�%DT� � �m��F��@"���)O�%�"�����.�'& DC�h�M�%DT�J& ��D��h�Z��/.>)+)aN2 �(� . 2 � -9N �|�$!"!D��7+��!"�O> �1�+x*a�1Y�'�����LT�H�<'�!"@V�.A+� � ���C#;LM���.�0���TN

*����C�0�1'1> �INag  2�(� -%� iKN����%LZ�,)+'�#()��._`�.���$#%������7R�0*+� �|oI-.o � �1��LT#;7;�1'�)+'�#(@+!"����N �6#(�&�&�1�;�Z��m�%7;� 7;A+'��$�+_���)���)��1'&)+'0���C�1�;�Z�����$#%�����&��*b�I�B*+�$'Z7 � A��C�0'Z�.!$����� �6#%�9-=�1'0�1��LT�m#(��|�1A+'K�.! �|�1�JYB#('��b�dg ¡ "+�1@+'0A��.'0E  ���� -9> ���.�;@ ��'�'Z�OiZN

*����C�0�1'1> �INIg  2�(� -�@�iZN � � ~�.�E��� ) �.F�� (�� ) F;�� ����� B � �W��);���%� �W�Z�IH �O����B ���q��� �H�h���9��F� BCDT�M�;� �f�O� �'& �*�0)O�5�%�C� �R�f�b� �0�%����� )%N��G*�N WN���*+�]�C���M>#�B*+� �|�b�"wO�1'K�C�"�JE,#.-q�OEb79�+�1E`>� A��J��'Z��!"�D�9N

*����C�0�1'1> ��N$>O���.�;�O�1'1>E�uN$>� ���"!"�]�T>��+N+g  2�(�%¡ iZN:�<'�'�#('��C�"_(���.!D�T>%��X+LT��)+���$#%���M>O�.��7W@V�%LZ�W)+'0#%)+o�._`�.���$#%�aN#� �@���9�C���T�+�%�����O�+�%��<%�H���;�1"��O� ���M�Z�M�%DT� �O� �H��);���%� �H�Z�5H �O�K��B �*� < " � � � ��� �I� ) �H/%�%>+)+)aN2 ��¡ .-2 � � N#�<�D��L1���Z�1Y��1EO> �1�+xF�J� �6��N

'��%L ��*+�$�+�+�1E`>��dN$>� *��1�$�9@V�%LZ*a>!�+N/g  ����9  iZN � �e)+!"�1�,�1�;�Z�����"#(���B��'��F�+#(�ILT#(��LT�1)+�0A��.!$�"����o���$#%���Mx �r�1w;���J�"�+_F�0*+�IwO�1'�@e�&#;79�1!tN1"���)O�%�"�����O�9>�M ��>   -   .   2 � N

'��.'ZLZ*+�m���a> �FN � Ndg  2�(� - iZN *a�.�+_(A��._(��!"����'��+�$�+_��"� LZ*+�"!D79'��1�}�.��7��+�1Ab'Z�.!I�+���CY�#%'0�+�Mx�<!��%�J���DLT�"�JEO>6L1��)��%LM�"�JE�����7 �0*+��LT'��$���DL1�.!�) ��'��"#;7:N �a��LZ*aN �r��)aN�� � -E1   > �6�1�;����'W-=#%'�r�]�C����'ZLZ*&�"� *a�.�b_%A���_%�O> �q�+�"wO�1'K�C�$�CEF#�-�����!"�5-=#%'��b���F�.�I�;���@ |�$�1_%#bN

'��.'�'�>� WNag  2�(� - iZN �)��BC���O�9Nr� �.�I"+'K�.��LT�D��LT#b> � � x"+'0�1�1�m���aN

'��.'Z�J*��.!$!�>A�+N �qN$>A �|�1Y LT#%�,@��O>H"BN�g  2���]¡ iZN �<�.�0���1'0��� #�-�)��.'K�.!$�1X9�D�9x � )��JE+LZ*+#(!"�"�b_%A+�D�C���DL�.)+)b'�#O�(L�*�N7<���)9�M�+�%� � �1$�BC/!DGF��%����� )�) ��BM����D (d� B��0�O� DGF;>��O>   � 2D.  ���� N

Page 197: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

 /� � ���$� � � � ������ � �

'�L �6!"�1!$!�����7�>A�+N*<N">� ��A+�&�1!$*��.'0�1>A WN���Nag  2�(��� iZN +$, �����O���%�����O� B���� �b�O���%�"�$�Z� �H��BM���@� ��)O�C� ��:� ��DT� B BC��� )A� � Fb�O� ��� � �.��� � � � �9�Z� B � �:� ��)O�����?B � �O� �&� ,O�M� D���B�� BMN �����8@b'���7;_%�O> ' � x'@�=�(�<'��]���TN

'�L �6!"#`�C�O�1EO> '�Ndg  2�(�9  iZN �|�1�JYB#('��b�&�.��7���*b�1#%'0�"���Mx �B*+��)+!��(LT��#.-,LM#%�+�+�]LT���$#%�+�D�C� �"�LT#%_(�+�"�0�"wO�I�0LT�"����LT�ON8$ BC/EDGF��%����)H��DZ�%��& D��h�M�%DT�K> �<g � iZ> ¡���� . ¡(� 29N

'�L �6!"#`�C�O�1EO> '�N">A *��$��79�1�m���+�a> � N '�N�g  2�(� -OiZN-'�����*+�+���1x��<'��1!$�"�&�$���.'0EI'����JA+!"�K�G-='�#(� �79���J��'0�"@+A+�0��7��e#;79�1!;#.-��.'0�"��*b�&�1���DLu-t�%LT��'��1�0'��$�1w(�.!�NF��� �+N(�ZN� WN ���.�e)+@��1!"!:g��67�N5iZ>��.F���I�%�I);���I�O� � � ��� )H���HB � �!��%��F����F�%����DZ�%��&+�E�"�$� BM>�)+)aN ¡ � 2�. �H1 � N � �m�J���1'K7+�.��x �|#%'0��*�|#%!$!�����7�N

'�L �6!"A��J�O�1EO>��uN �qNug  ��(�(¡ iKN+"V����7 -=#%'0Y���'Z7 ����7R'0��L1LTAb'��1�;���+�1A+'K�.!��+�1�JYB#('��b�|����7 _%���+�1���DL)+'�#(_%'K�.�m��-=#(',�C��#;LZ���m��'��O�1�H����7 �0�"�&�,�J�1'��$����-=#%'0��L1�%�J���$�+_+N � ��LZ*aN �r�1)�N ���Oo �%¡ o¡�� >! |��)��.'0���&�1�;�B#�- �6#%�&)+Ab���1'q�;LT�"����LT�O>��B'0#.Y�� �|�b�"wO�1'K�C�"�JEO>-�<'�#�w;��79����LT�O> �r*+#;7;��J�C!�����7�N-'��(�C����'���� �B*b���C�D�TN

'�L ' �"!$!��.��> �qN"> �`�&#%!$�1���C�;EO>C�uNOg  2�(��� iZN � ���.!$E9�1�$�+_��fLT#%�+�b��LT���$#%�+�D�C�a�&#;7;�1!O�(�u�q�CEb�C�0�1�#.-��C#�-=�<'�Ab!"���MN%�a��L�*�N ���1)aN � �|o ���Oo ¡��%¡ o ��� >��|�+�$wO�1'Z�J�"�JEq#.- �6#%!$#%'Z�(79#+>b�B#%A+!D79�1'�> � �HN

' #%'��t>'FN">2 6#%�O#`���1Y��;>(�FN(g  ����(� iZN �q�1A+'Z��!%�+���CY�#%'0�+���0*��.�a!$���.'0���0#d7;����LM'��"�e�"���������C�$�&�"!D�.'�(�.�!$J�/L�*V�.'Z�(LT����'Z�TN6���@ HN ��N �a#%A+'0�1���1�;E�g��67�N5iZ>a� ���1�O�%DT� B ��� �W��);���%�!��� �C�O���F�%�����O�$ � ��DT� B BC��� )0& / BM�J���?B ��>9)+)�N ¡%¡ -�. ¡(¡(� N<�;��� '������1#b> � � x ' #('�_O���@�I�.A;-=�m�.�+��N

' #%�1�1'�> '�N �qN">N �B�1*+'0�m�.�+��> '�N�g  ���� - iKN������(79�"�+_FY��$��*��.�0���1�;���$#%����!a�"�&)V�.�"'0�&�M�9�K�Tx �@+'Z���"�+ot7+���m�._(��7~�e#;79�1!6#.-q�+��_%!"�]LT�I�.�V7��.�0���1�;���$#%����!�79Eb�C!$�1X9�D�%�MN'��� �IN � N ���1�"!$!"E �WN;��N+�O*��.'0�O�1Emg��67+�MNniK>�"��O�+� � DM�����O�%��BM�<���H�:� ���HDGF�� Bq��� �I�%�I)9�0�%� ���O� )�);� )9�4$ � �

DT� B BC��� )%>�)+)aN � 1 � . � � 19N �q�"!"!D��7+��!"�O> �1�+x�*a�1Y�'��1��LM�F�<'�!$@��.A+� � ���J#;LT���������MN' A+�+'�#b>)�uN �4N<g  ���� - iKN ���1)����.�IA+�;���$!u@�#%'0��7�x � )������0�1'����J�1!"��LM���"#(���C�0'Z�.�0�1_%E`N ���E�+Na��N

' #O#;79EO>I��N4�+N �d�.���J#%�a>; �IN��uN *��$)+)+�m���+� gt� 7b�TNniK>d� ���1�O�%DT� B ��� �H��);���%� �M���C�O� �F�%�����O� $ � ��DT� B BC��� )C& / BM�J���?BJM+>q)+)aN   1!1   .   1!1 � N��;��� '������1#b> � � x ' #%'0_O���

�I�.A9-=�m���+�aN

Page 198: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �  /� 2�|�1YB��!"!�> � N$>� �O�$�&#%�a>G�WN+g  2���;  iZN �6#%�&)bA+���1'G�C�"�,A+!D�.���$#%�H#.-�*;A+�m�.�F�0*+�"�b�9�$�+_+N & D��h�M��DT�Z>

� ��MBg ¡ � � 2 iZ> -!1  %  .A-!1  /� N

�|#%'0A ��J���T> '�NN�+Nag  ���� 1 iKN7&N$8&N&�2r� B��1& / BM�J����� B���� � B �6) ���9�KNB�-�B�+�J����L%N�|#O�J#.-t�C�;EO> ��N '�N">)�<�.!$�&�1'0��>#�dN�+N">� '�L��d�$�+!"�1E`>u��N �qN�g  2�(� �;iZN ��A+!$�1oh)b!"A��Joh�1XbLT�1)b���"#(�

�&#;79�1!:#.-GLT!��(���J�nU:L1�����$#%�m!"����'��+�$�+_+N $�BC/EDGF��%����)H��DZ�%� (d� ���h��Hu> �����ag   iZ>�2 ¡ . � � N�<�.'0�9�$�a> � NF�+Nag  2�(� -OiZN��<*+#%�+#(!"#(_%��L��.!a'��]LT#;79�"�b_8�$�&!"�1X;��L��.!:79��LT�D�C�$#%�ax6�0:��LT�K�B#.-G�C)��1!"!$�"�+_(o

��#(o��J#%A+��7�'���_%A+!D�.'��$�JE�79�1)��1�V7 #%��*+#�Ys'0�1_%Ab!��.'0�"�JEm���d7;�TU��+��7:N ���� �O�@/&�O� ��"���)�

�%�"�����O�9> ���ag   iZ> � ¡ .-2 ¡ N

�<�.�0���1'K�C#%��>+�FN$>9�O�1�D79�1�;@ ��'�_+>O��N$>� '�L �6!"�1!$!��.�V7�>(�+N *<N+g  2�(�(� iZN �6#(�+�+��LM���"#(���6�.��7,79�D��LT#(�+o�+��LT�0�"#(���Tx � L�,OA+�"'0��7m79E+�J!"�1X;���F�"���mLT#(�&)+A+�K�.�0�"#%�V�.!��&#;79�1!�#.-�'��]�%79�$�+_m)+'�#;LT�]���C�]�TN�����IN � N-'�N-' #('�'��D�&g��67�N5iZ> $ �O���%�$�"�Z� �H��BM���@� ��)O�C� � �:� ��DT� B BC��� )+�'� ��������DZ�%�����O�HB��C�O��%BC/!DGF��%� � ) /8�O� �m� � )9� �������%����)H/.>+)b)aN  1¡;  .  2�9  N!�qX -=#('Z7�x��6!D�.'�����79#%� �<'����0�TN

�G�$�+�O�1'�> ��N:g  ����9  iZN ��A+!"�]�B#.-/!��.�b_%A���_%�ON7& D��h�M�%DT�Z>��A:��%>2 ¡ 1D. 2 ¡ 2;N

�G�$�+�O�1'�>G�VN">� �<'��$��LT�O> � N6g  2�(�(� iZN �q��!��.�b_%A���_%���.��7�LT#%�+�b��LT���$#%�+�D�C��x � ���.!$E+�J���d#.-��)��.'K�.!$!"�1!�79���J��'��$@+A+�0��7&)+'�#;LT�]���C�$�+_,�&#;79�1!:#.-6!D�.�+_(A��._(�F�%LC, A+�D�C�$���"#(�aN�"���)O�%�"�����O�9>�� �%>��¡ .  ��(¡ N

�G!D�.A+��>� WNagh�$�m)+'����0��iKN |#(A+@+!$�W7;�����J#;LT�������$#%����Y��"�0*+#%A+�q�&#;79Ab!��.'0�"�JEON8<���)9�M�+�%�)� � "<��������DZ�%��O� � +-, ���M�@�*�8�M�9�t�%� �H��);� ���%BC/EDGF��%����)H/.N

�G!D�.A+��>� WN �qN$>( '�L �6!$�1!"!D�.��7�> �+N *<N+g  2�(�%¡ iZN � �1�+�1'K�.!"�$���.�0�"#(�WY��"�0*,LT#%�e) #(�+�1�;���D�.!;�.�0��'K�%LTo��#('Z�TxaY�#%'Z7H�.��7W�b#%�;YB#%'K7�'0���%79�$�+_q�"�H�.�?�.���0'Z�(LT��#('<�+�1�JYB#('��:N����0$�� ��DT�Z� �H��� ) B�� ����F����� �M�J�Z�M�9��F��f�+�N);�%�7"��O� ���M���M��DT�>� �?� F�� "�� )`�%�"�������,& D��h�M�%DT� & ��D��h�Z��/.>a)+)aN � - �/. � - � N�|�"!$!��07+�.!$�O> �1�+x%*a�1Y�'�����LT�H�<'�!"@V�.A+� � ���C#;LM���.�0���TN

�G!D�.A+��>N WN �qN$> '�L �6!"�1!$!��.�V7�>��+N%*<N$>+�O�1��7;�1�9@��1'0_+> '�N+��N">A �/�.���0�1'Z�J#%�a>��FN;��N�g  ���� �;iZN��q�+o79�1'K�C�Z����79�$�+_W�+#('��m��!��.�V78�"�&)V�.�"'0��7�Y�#%'K79oh'0���%7;�"�+_bx��6#%�&)+Ab�Z�.�0�"#(���.!�)+'0�"��LT�$)+!"�]�u�"�, AV�%�C�$oh'0�1_%Ab!��.'?79#%�^�.�"�V�TN>�a��LZ*aN ���1)aN)�8 �uN � ����N � �+N329> |�1)���'����e�1�9�q#.-��6�JE+LZ*+#%!$o#%_(EO> ���.'0�+�1_%�$� ' �1!"!$#%� �|�+�$wO�1'Z�J�"�JEON

Page 199: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

 /� � ���$� � � � ������ � �

�G!$A+�+�O�1�0�1> �FN"> '���'ZLZ*+�m���a> �FNOg  2�(� 1 iZN"+'0#%� '0#%����!"����'��+�$�+_q��#f�CEb�C����� @bA+�"!D79�"�+_bNH�a��L�*�N�r��)aN � � * � 1(-E19> �6�1�;����'u-=#%' �����C����'ZLZ*8�$� *a�.�+_(A��._(�O>��|�+�$wO�1'Z�J�"�JEI#.- ���.!"�5-=#%'0�+���H�.��;�.� |�"��_%#+>*a� �%#%!$!��;> � � > � -!1 �(¡ o�1   - � N

�G'K�.�0�1>�*<N">���|#O��) ��'1>��uN�g  ���� - iKN �B*+�m*;E9)��1'0)+!����+�m���+�"�m����#(' �6#(�&)+A+�0�1'I)+'�#(_%'K�.� �tN� w(�.�$!��.@b!"�d@;Em�.�b#%�;E9�&#(A�� -=��)&-='0#%� L1�MN�'0A+��_(�1'Z�MN���79A�N

�r�1_(_%�D�9>��+N � N$> '��.'K�C!D�.��7�> �uN '�N$>N �B�1'0��79��> �IN���Nag  2�(�(� iZN��6#(�&)��1���$���$wO�d79E;�����&��L1�6�"��F79A���!"o='�#%Ab���FLM#%�+�+�]LT���$#%�+�D�C���&#;79��! #�-6)+'0�"�;��o=��#%ot�C#(A+��7m��'Z����� -=#('��m�����$#%�aN�"��������"� ,& / BM�J���?BM>��O>2E1 � . 2 � � N

�r#`�C�1�;@��1'�_b> �qN �INag  2�(�(� iZN �<�0�O�M�%��� )&��F�� D �O�+� � DM�����O� �T�Z�IH �Z�M� B=���Z�$����� )��O� � BC��)9� � B �q�� �Z�IH �O��� � � �9�Z�#� � �O���%�V���0� �H��� )%N)�<*aN WN9�0*+���C�D�T>-�<'��$��LT�1�0#%�J�|�b�"wO�1'K�C�"�JEO>��q'Z79��'��q#+N�(�;  � 1E2 ¡ > �|�+�$wO�1'Z�J�"�JE ' ��LT'0#.U�!$�m�8���9�0�1'��������$#%����!�> � �+� � '�@�#%'�> '@�ZN

�rA+�e�1!"*���'���> WN���N">4�q�"�;��#%��> � NB��N"># ���$!"!"�D�.�m�M> ��N �+Nqg  ������ iZN *�����'��+�$�+_��"�;����'�����!'��1)b'����J�1�9�K�.�0�"#%�V�u@9EI�1'0'�#('<)+'�#()��._`�.�0�"#%��N ��� WNO��N ��A+�&�1!$*��.'0�� �+NH*<N '�L �6!"�1!$!�����7g��67+�MNniZ> $ �O���%�$�"�Z� �H��BM���@� ��)O�C� � �:� ��DT� B BC��� )+� +-, �����O�0�%�����O�HB ����� F�� � ��D1� � BM����)-DT�5);��� � �D ��)O�%�"�����O��� �%�%� )A�8����>�L�*���)aN � >+)b)aN ¡9 2� . ¡ � -;N �����8@b'���7;_%�O> ' � x '@� � �<'����0�TN

�rA+�e�1!"*���'���>8 WNB��N$> '�L �6!$�1!"!D�.��7:> �+N�*<N|g  ������ iKN �q��!"�]�.'��b�"�+_���*+��)��%�J�8�0�1���J���8#.-�<�+_%!$���C*�wO��'�@��MN1���E�+N.*<N '�L �6!"�1!$!�����7J WN��rN �rA+�e�1!"*���'��Igt� 7b�TNniK> $ �O���%�$�"�Z� �H��B

���@� ��)O�C� � �:� ��DT� B BC��� )A� +-, �����O�0�%�����O� B ���~��F�� � ��D1� � BM�t� )-DT�I)9�Z� � ��D � )`�%�"�����O� � �%�%� )A�8��N��$�BC/!DGF��%� � ) ��DZ�%�q�O� �������%����)H��DZ�%�6� � �9�Z� BM>�LZ*���)aN  �� >B)+)aN -   � .A- �O  N �����8@b'���7;_%�O>' � x '@�=� �<'����0�TN

�;�.'0��#%'0��> � N�g  ����(� iZN "V'0#%� �e#;79�1!��I��#��+��A+'�#()��CEbL�*b#%!"#(_%�DL1�.!q7+���Z���.��7�w;��LT�ewO�1'Z�0�9N����� N� |�1�+���M> �qN��`�1�&�1�+�]�9>N ��N��B���J���%L�L�*+�/g��67+�MNniZ> $q�M� B=� � DM�����.� B �O�ID ��)O���"�����.�?� ��)

� ���%BC/EDGF��%����)H/.>O)+)�N2 � . ��¡ N#*�#%��7;#%�ax *a�1Y�'0�1��LT�H�<'�!$@��.A+� � ���J#;LT���������MN�O�1��7;�1�9@��1'0_+>�'�N���N<g  2�(� - iZN �6#%�+�b��LT���$#%�+�D�C� Y��"��*b#%A+�I���]�.'Z�MN0������N d�1w;���Fg��67�N5iZ>4"��O�

� � DT�����O�%��B2� � �.F�� �O��/,�O� � �:�0�HDT����DT�Z>�)+)aN � � .   -(-9N �|�1Y 6#('��:x �qXO-=#%'K7@�|�+�"wO��'Z�C�$�JE�<'����0�TN

Page 200: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �  /�(��O�1��7;�1�9@��1'0_+> '�N9��N$>( '�L �6!"��!"!�����7�>��+N!*<N�g  ��(��� iKN � 79�D�C�0'��"@bA+����7:>%79��wO�1!"#()+�&�1�;�Z��!%�&#;79��!

#.-/YB#('Z7R'0��LT#(_%�+�$���"#(���.��7m���.�&�$�+_+N8$�BC/!DGF��%����)H��DZ�%� (f�$���h��H�>��� ag �;iZ>2(- ¡ . 2 �(� N�O�1��7;�1�9@��1'0_+> '�N<��N">� '�L �6!"�1!$!��.�V7�>��+N*<N6g  ��(� 1 iKN ' #%'0�8Y�#%'Z7b��@+A+�?�C�0�"!"!6�+#�!"�1X;��LM#%�ax

�r��)+!"E,��#e�B���C�b�1'B�1�q��!�Nag  ��(� 1 iKN $�BC/!D F��%����)H��DZ�%� (d�$�C�h��Hu> ��%�g ¡ iZ> � � � . �H2�-9N�O� $J�+#�Yq�C�;��>)�dN��+N">� ��#O�J�1�;@ ��'�_+> �qN ��N6g  2�(��� iZN �d���B�Z��!"�:x � )V�.'Z��!"!$�1!6�+�1�JYB#('�� �0*��.�

!"����'����d�0#R'0���%7��.!$#%A�7:N ��� �+N � N � ��7;�1'Z�J#%� ��N �r#`�C�1�;-=�1!�7�gt� 7b�TNniK> �H��);� ��D ��� �� ) ����� )+� � ��);� �O�%�����O�HB � �?�Z� B��0�O� DGF;>O)+)�N ���%¡ . ��� -9N �����8@+'0��79_(�O> ' � x '@�=� �<'����0�TN

�O*��.!$!"�DLT�O>#�dN6g  2�(��� iZN �a� ���c� � )9� ���%BC/!DGF��%����)H/m���@�8���9���%��BM����)-DT�5);���KN ���.�,@+'0��79_(�O>��1�Fx���.�,@+'��D79_%� �|�+�"wO��'Z�C�$�JE �<'����0�TN

�O*��.!$!"�DLT�O>%�dN$> ����'�'0�"�+_(��#%��>���N �[N$>N '�L ����'��0*9EO> �INag  2�(�(¡ iZN �����%7;�"�+_,Y��"�0*+#%A+�f�C���m�.�+o���DL1�TN � )9�O�Z�J�M��� / <%��);�M�+�%�#� ��+-, ���M�@�*�8�M�9�t�%�!$ BC/EDGF��%����)H/�> ��:.�d>  ( %  .  1¡�� N

�O*��.�b�+�M>4 WN �IN">���O�1N8�%#(*+�a> '�N�"�NBg  2�(� �9iZN �6*��.'K�%LT�0�1'��D�C���DL1�W#.-�79���0�C#;LT�D�.@+!$�R*;A+�m���!"����'��+�$�+_,�CEb�C�0�1�m�MN �.F��|2f� Fb�������O�0�%���O� �82q���H���'& D��h�M��DT� BM> � %:g ¡ iK> ¡���� . � � � N

�O!"�1�]�.�:>���Ndg  2�(� �9iZN �6#(�&)+A+�0�1'&�&#;79��!"!"�$�+_�#.-,LM#%_%�b�"���$wO� )+'0#;LT���0�Tx ���9�0'�#;79AVLT���$#%�aN ����+N ���$!"���M> �qN *a�.���$�&�1'�>! �qNu�O�0�1wO�1���Ig��67+�MNniZ>#"��%�"�"� DT�J� �%$ �����M� B ��� �����'& /(�����

BC�*)+� �O� "��O�+� � DM�����O�%��BM� � �9�Z� B��O� �@$ BC/EDGF��%����)H/�> )+)�N � . � N;�B*b�@�|�+�$wO�1'Z�J�"�JE�#.- qA+�1�1���J!�����7�> � A��C�0'Z�.!$���;x��6#%�&)+Ab���1'd�;LM�"�1��LM�1 |��)��.'0���&�1�;�1N � �]L�*aN �r��)aN�- ��� N

�O�&�"�0*a>���N%��N$>!*a���+_O�J��#%��> �qN$>� �|�D�C@��1����> �IN���N9g  ���� - iKN�B*+��L��%�C�B-=#('u'0A+!"�]� �$�W'��]�%�C#(�+�"�b_+N"���)O�%�"�����.�1& D��h�M��DT�Z>��� �>   . �H1;N

�O#%!$!��9>O��N � N">E*��1w;�"�a>(��N">� "�!"�1�D�C*+�1'�> '�NOg  2�(�(� iZN � L�LT�1!"��'Z�.�0��7d!"����'��+�$�+_q�"�I!��1EO�1'0��7d�+�1A+'K�.!�+�1�JYB#('��b�TN�"��������"� ,0& / BM�J���?BM>��O> � -E2D. �%¡(� N

�O)+�"wO��EO>��+N '�N�g  ��(� - iKN �.F����\�%�%�t�%�����O���B� ��� ���M�Z�M�%DT�;�F�O�N);�%�6gC�O��LM#%��7F��79�$���"#(��iZN)�<'����+o���DLT���d��!"!�N

�u��@��%LZ*+�+�DL��:>��dN � N"> "���79�1!$!�>�*<N%��NOg  ����%¡ iKN � BC��� ) �0)O�������1�O�����%�J��BM���%����BM����D Bdg   �C����79�$���$#%��iKN�|�1Y 6#%'��:x��f�.'�)��1'; ��#�YIN

Page 201: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

 /� � ���$� � � � ������ � �

�u��'Z�.@V�.�a> �IN">� '�L �6!$�1!"!D�.��7:>(�+NE*<N+g  2�(��� iZN �6#%���J)+�"'K�%LTEH��0:��LT�Z���"�WY�#%'K7W)+'�#(�9A+�VLT�������"#(�aN<%��);�M�+�%�#� ������ �O�@/8�O� � � �O� )�);� )9�Z>�� �> � 1 � . �%¡9  N

� ���0�.A+'0#+> � N$>8 �O� $J�b#.Yq�J�9�t>;�dN8�+N�g  ����(� iKN � )��.'K�.!$!"�1!��+���CY�#%'0����*����F!"����'����F��#�)b!��1E@��%LZ�;_O�.�e�&#%�aN � ��LZ*aN ���1)aN � ��� ��o ��� oI-9> �6���9�0�1' -=#('��6#%�e)+!"�1XH�OE+�J���1�^� �r���J���.'KL�*�>�|�+�$wO�1'Z�J�"�JEW#�- ��!"!"�$�+#%�D�B���6�|'�@������.o �6*����&)��.�$_%�aN

� �1Ab@ ��'1> �WN *<N<g  �� 2E2 iKN �<*9Eb�C�$#%!"#(_%�DL1�.!�)��CEbLZ*+#%!$#%_%E`NW�f�+�N);�%� (d�$�C�h��H � � $�BC/EDGF��%����)H/.> �%>- ��� .A- ��� N

� #�YB��!"!�> � N � N$>4 �O*��1w;!"�$��>;�+N �4NIg  ��(�(¡ iKN �B*+����X9�0'Z�%LM���"#(� #�-F'0�TU��+��7�'�Ab!"���8-='�#(��9�b#.Y�!$��79_(�1oh@V�%�C�]7^�b�1A+'Z��!a�+�1�JYB#('��b�TN ~�HDGF���� � �<�0�O�M�%��� )(> � �ug   iZ> �`  .   1   N

�B��!"�D�.�;�1>)*<N � N6g  2�(� �;iZN � ��*b�1#%'0E�#�-q��*+�,!"����'�����@+!"�`N "����0�0)9�%��DZ�%�����O� B � �e� F��F� " �>�#%�g  (  iK>  % 1¡ �/.  %  �G-9N

� ���+�1�1�;EO> �IN!*<N+g  �� ��� iKN��<�+_(!"�D�C*F#%'0��*+#(_%'K�.)+*;E�x���Z�u_('Z�.)b*+��L1��!��C�0'�A�LM��A+'0���.�V7[�$�Z�a'��1!D�.���$#%���#,�J#%A+��7:N (d�0� �H��� ) (f� B��0�O� DGF � )9�O�Z�J�M��� /.>��<g ¡ iZ> � 2�.   1E29N

� ���+�1�1�;EO> ��N�*<N g  ���� 1 iKN �.F�� BM�t� )-DT�I)9�Z� � � + � )%����B F �O����F���)O�����%F�/�N.�B*+�;�d��_%A+�Ox-' #(A+��#(�aN��� $J�:> � N�g  2��� � iZN (;) �"� B � � �:� �O�F)9�%DC���%�����O� �C�O�W� F�� +�� )%����B F��5�O� )G)9� )9�KN *a�.�+_(A��._(�m�.�V7

*a�.�+_(A��._(� *����.'0�+�"�b_R�O��'��"�]�T> �q#+N   -;N*�#%��7;#%�ax �qXO-=#%'K7%�q�+�"wO�1'K�C�$�CE �<'0�����MN

���"!"�]�T>��+N">*a�����$�&�1'1> �qN"> �O�0�1wO�1���M> �qNug  ���� �9iKN �6#%!"!$��LT�0��7&)��.)��1'K�r-='�#(�c�,�CE;�&)�#O�J�"A+�#%� LT#%�b�+��LT�0�"#%�b���C�e�&#;79�1!D�8����7 )V�CEbL�*+#(!"#(_%EON �a��LZ*aN ���1)aN4- �(� >� |�1)���'����e�1�9�,#.-�6#%�&)bA+���1'q�;LT�$�1��LT�O>-�B*+� �|�+�$wO�1'Z�J�"�JEW#�- qA+�1�1���J!�����7�> � A��J��'K�.!"�D�9N

���"!"�]�T>1�+N$>4 �q!"!$�"!D�9> '�Ndg  2�(�(¡ iZN����;���1'K�C��LM���"�b_�'0�1_%�$#%���Mxy��*+���O��Ey��#}LT#%�,@+�$���.�0#%'��D�.!�C�0'�A�LT�0A+'��I�$�R*b��7+79���RAb�+�"�f�C)��(LT�ON ���~�VN!�+N��d�����C#(�a> �+N� WN �6#�Y��.��>! �qN*<N � �"!"�]�g��67+�MNniZ>;� ���1�O�%DT� B���� �H��);���%�+��� �C�O� �F�%�����O� $�� ��DT� B BC��� )1& / BM�J���?B6:%>()+)aN�- � . ¡(¡ N+�;���'��.�0�1#+> � � x ' #%'0_O�.�E�I��A9-=�m�.�b�aN

���"���J��#%��> �uN#�WN|g  ���� �9iKN��f����� =�D����%�+���;�C�Z�$��� )9�M��D]��gJ�O��LT#(��7y��79�$���$#%��iKN �r���(79�"�b_+> ' � x� 7+79�D�C#(�+o �����J!"�1EON

Page 202: University of Queenslandstaff.itee.uq.edu.au/janetw/papers/PhD 1995 Bakker.pdf · 1$ G i \ Z ] Vds\ `UYd [`b UYi \ Z ] Vds\ `U `b U*dsV_ w 5 - G c@S(i U*W U*]^d k U&i`d i U*`U X1`

���,� � � � ���� � � �  /� ���#O#;7�> �qN �qNBg  ���� - iKN����&)+!$��L1�����$#%���d#.-��C�$�8Ab!��.�0��7 !"�]�C�"#(���1X;)��1'��$�&�1�;�Z�r-=#('W��*b�R�$�9�0�1'�o

)+'����Z�.�0�"#(��#.-�!$���C�$#%���q�"��'��]�.!<�+��'�wO#%AV�d�CEb�C�0�1�m�TN����'�N � N � '0@+�"@�> WN ����)+!����a>��+N �qN '���'Z�C*V�.!"!�g��67+�TN5iZ> �H��)9�0�%��� � �9�Z� B�� � �5�O� )�);� )9�;�:� ��DT� B B�� BM>%)+)�N � � 2D.-2E1 � N �|�1Y6#%'��:x � L1�(79�1�&�DL �<'����0�TN