Development of a Motion Sensing and Automatic Positioning Universal Planisphere...

Research ArticleDevelopment of a Motion Sensing and Automatic PositioningUniversal Planisphere Using Augmented Reality Technology

Wernhuar Tarng Jiong-Kai Pan and Chiu-Pin Lin

Graduate Institute of e-Learning Technology National Hsinchu University of Education Hsinchu Taiwan

Correspondence should be addressed to Wernhuar Tarng wtarngnhcueedutw

Received 3 June 2016 Revised 9 December 2016 Accepted 26 December 2016 Published 14 February 2017

Academic Editor Stefania Sardellitti

Copyright copy 2017 Wernhuar Tarng et al This is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work is properlycited

This study combines the augmented reality technology and the sensor functions of GPS electronic compass and 3-axisaccelerometer on mobile devices to develop a motion sensing and automatic positioning universal planisphere It can create localstar charts according to the current date time and position and help users locate constellations on the planisphere easily throughmotion sensing operation By holding the mobile device towards the target constellation in the sky the azimuth and elevationangles are obtained automatically formapping to its correct position on the star chartThe proposed system combines observationalactivities with physical operation and spatial cognition for developing correct astronomical concepts thus making learning moreeffective It contains a built-in 3D virtual starry sky to enable observation in classroom for supporting teaching applications Thelearning process can be shortened by setting varying observation date time and latitudeTherefore it is a useful tool for astronomyeducation

1 Introduction

Astronomy is a natural science for studying celestial bodiesin the universe and its scope covers the entire astronomicalobjects and their interactions Therefore the earth and thesolar system which we live in are also included The changesof astronomical phenomena have great influences on ourdaily lives Observing celestial bodies such as the sun themoon and stars is an essential part in astronomy educationBy observing the astronomical phenomenon students caninvestigate the relation between the movement of celestialbodies and their interactions and use scientific methods tosolve problems for deriving answers so it can enhance theircritical thinking and problem solving skills

Some astronomical phenomena such as sunrise sunsetand the movement of stars in the sky can be seen in ourdaily lives and they are directly related to the rotation andrevolution of the earth Since the ancient times humanbeings began to keep track of stars in the night sky totell directions and seasonal changes By connecting brighterstars with imaginary lines the ancestors created a numberof constellations and each constellation was named after its

pattern and mythological story In 1922 Russell aided theInternational Astronomical Union in dividing the celestialsphere into 88 official constellations [1] To define the starrsquosprecise position in the sky Lundmark at Lund Observatoryled a group of draftsmen to complete the project of markingsome 7000 stars on the celestial sphere where the brightnessof stars was represented by different sizes of white dots [2]

Observing stars is an important learning activity inastronomy education However it has to be conducted duringnight time and the observation is easily affected by weatherconditions or obstructed by surrounding high buildingsWithout facilities such as the dome screen or simulation soft-ware like Stellarium (httpwwwstellariumorg) and GoogleSkyMap (httpgroupsgooglecomgroupgoogle-sky-map)star observation can only be done in its natural wayThat is ithas to be conducted outdoors at night according to the timeand season of the starrsquos appearance

Stellarium is free desktop software which renders realisticskies in real time with Open Graphics Library (openGL)(httpswwwopenglorg) With Stellarium the user can seethe visible stars in the sky with the naked eye binocularsor a small telescope It can also be used in planetarium

HindawiMobile Information SystemsVolume 2017 Article ID 3167435 13 pageshttpsdoiorg10115520173167435

2 Mobile Information Systems

projectors by setting the userrsquos coordinates Google Sky Mapis an Android version of Google Sky The application enablesthe user to pinpoint the exact location of the stars planetsand other celestial objects in the night sky It can be used ona mobile device as an augmented reality application Whenpointing the mobile device at the sky the user can see detailsof 3D starry sky represented by a sky map

Michie [3] and Orion [4] considered star observation inthe night sky important and helpful for constructing astro-nomical concepts but it is difficult in practice for teachersto conduct teaching activities during night time Withoutsufficient observation and verification students can onlythink about themodels of earth and celestial sphere to explainthe starsrsquo movement in the sky due to the earthrsquos rotation andthus some common misconceptions in astronomy may stillexist [5ndash7]

The traditional planisphere has the advantages of lightweight portability easy acquisition and low price but italso has some restrictions such as applicable areas time andvisible stars It is an astronomical observation tool developedby projecting the celestial sphere and its stars towards thenorth celestial pole to form a star chart (or sky map) As aresult the constellations shown on the star chart may oftenbe distorted especially those in the southern sky To remedythis problem most planispheres provide both the northernand the southern star charts on the front and the back sidesfor easy star observation

When using a planisphere to find constellations in thenight sky the users must rotate the movable portion untilthe current date and time marked on its edge are alignedThe compass and protractor must also be used to measurethe target constellationrsquos azimuth and elevation angles Sincethe equatorial coordinate system in the celestial sphere is dif-ferent from the Cartesian coordinate system on the groundstudents may have difficulty locating a constellation on thestar chart or deciding when to switch to the northern or thesouthern star chart In addition the traditional planisphereis only applicable to a certain area (or latitude) If theobservation is to be conducted in another areawith a differentlatitude we need to use the planisphere suitable for that area

With the advance of information technology computersoftware can be applied to simulate scientific phenomenasuch as physical or chemical reactions for observation in themicroscopic world It can also reduce the amount of experi-mental variables for learners to focus on specific subjects toenable conceptual change [8 9] Nowadays mobile devicessuch as the personal digital assistance (PDA) smartphoneand tablet PC have been integrated into different educationalapplications As a result learning activities are no longerrestricted to the classroom In other words they can bedone anytime and anywhere by using any device to achieveubiquitous learning [10]

Recently the hardware of mobile devices becomes morepowerful and the built-in sensors such as the GPS elec-tronic compass and 3-axis accelerometer can provide theinformation of position time direction acceleration andso on to support the design of simulation software forapplications in different areas of education Schiller andVoisard [11] proposed the concept of context awareness by

using the GPS to obtain the userrsquos current location forproviding immediate servicesThemain objective is to satisfythe sensational requirement by updating the informationaccording to environmental changes such as local date timeposition and direction

Augmented reality (AR) is a view of the real world whereelements are augmented by computer-generated situations toenhance the perception of reality Its purpose is to incorporatevirtual objects into the real world to enhance their interac-tions with the users According to Azumarsquos [12] definitionAR is an evolution of virtual reality (VR) with the followingfeatures (1) interacting with real and virtual environments(2) providing real-time feedback and (3) necessarily being inthe 3D space In comparison VR is a technology to createan interactive environment for simulating the real worldthrough onersquos sense organs The users can see hear and feelin the created scenes as if situated in the real world andeven interact with the objects in the virtual scenes [13] ARintegrates the real world with virtual objects to increase thesense of reality in a more interactive way and it providesuseful information not directly available to enhance onersquoscomprehension in the real environments

Liu et al [14] introduced several AR systems with whichstudents can view the virtual solar system on the classroomtable and visualize the process of photosynthesis Kerawalla etal [15] combined the whiteboard projector web camera ARtechnology and 3D modeling package for students to learnabout the earth and the sun as well as the changes of dayand night It was discovered in their study that teachersrealized the advantages of using 3D images and believed thatAR can make inaccessible subject matters available to stu-dents Therefore AR can increase learnersrsquo interaction withthe real world and provide them with useful informationfor perceiving some scientific phenomena which cannot beexperienced in the real world [10]

In this study we have combined the AR technology andthe sensor functions of GPS electronic compass and 3-axisaccelerometer on mobile devices to develop a motion sens-ing and automatic positioning universal planisphere It cancreate local star charts according to the current positiondate and time and help the user locate constellations onthe star chart easily through motion sensing operation Byholding the mobile device towards the target constellation inthe sky the azimuth and elevation angles are mapped to thecorresponding position on the star chart With the functionof searching constellations the user can find the targetconstellation easily by following the instruction By settingthe observation date time and latitude the user can seethe change on the star chart to understand that constellationsseen at different time in different seasons or at differentlatitudes are also different

The system can shorten the learning process by changingthe setting for observationWith the built-in virtual 3D starrysky it can solve the problem of being unable to observe starsdue to bad weather conditions or obstruction by surroundinghigh buildings In addition the physical operation can makea deeper impression on students enabling them to storethe acquired knowledge in long-term memory The systemcombines observational activities with physical operation

Mobile Information Systems 3

Figure 1 Developing the celestial sphere and earth model

and spatial cognition for developing correct astronomicalconceptsTherefore it is a useful teaching aid and observationtool for astronomy education in elementary and high schools

In this study a teaching experiment has been conductedto investigate studentsrsquo learning effectiveness by using theuniversal planisphere as a tool for star observation Theresults are compared with those of using other tools In addi-tion a questionnaire survey has been performed to analyzeand compare the attitudes of students after using differentobservation tools and the results could also be adopted as areference for improving the system functionsThe rest of thispaper is organized as follows Section 2 describes the systemdesign Section 3 provides the experimental results and dataanalysis and Section 4 is the conclusion

2 System Design

Theobjective of the proposed system is to improve traditionalplanispheres by providing the functions of motion sensingand automatic positioning so that students can learn tooperate the planisphere easily and establish correct conceptsin astronomical observation and spatial cognition It isdesigned as a teaching tool for the learning unit of ldquoStarObservationrdquo in science and technology curriculums forelementary schools with the following learning objectives[16]

(i) Learn to use the planisphere and know the patterns ofconstellations and their mythological stories

(ii) Understand that stars are moving from east to westthrough observation

(iii) Understand that the starry sky in different seasons isalso different

(iv) Learn to locate the North Star using the constellationsCassiopeia the Queen and the Big Dipper

The system of universal planisphere is composed ofseven modules including date and time adjustment visualangle control star chart generation star chart switchingconstellation positioning online test and test results uploadTheir functions are described briefly in the following

(i) Date and time adjustment the user can set differentdate and time for observing constellations

(ii) Visual angle control the system provides zoom-inand zoom-out functions so that the user can seeconstellations and their information more clearly

(iii) Star chart generation the local star charts can begenerated according to the GPS data (longitude andlatitude) as well as the current date and time

(iv) Star chart switching the system can switch betweenthe northern and the southern star charts accordingto the userrsquos directionwhen holding themobile devicetowards the sky

(v) Constellation positioning the system can obtain theazimuth and elevation angles of the target constella-tion for mapping to its corresponding position on thestar chart automatically

(vi) Online test an online test is provided to assess if theuser can operate the planisphere correctly to find thetarget constellation

(vii) Test results upload the userrsquos test results can beuploaded to the server via wireless networks for theteacher to examine their learning achievement

21 Celestial Sphere Since the stars are very far away fromthe earth if we can create an arbitrarily large and transparentsphere called the celestial sphere with its center overlappingwith the earth center the connection line between theearth center and the star will intersect with the celestialsphere Hence the longitude and latitude of the star canbe marked at the intersection point on the celestial sphere(Figure 1)

In this study the celestial sphere and constellationsmodel(Figure 2) is developed to simulate the starry sky and togenerate the star charts on the universal planisphere Afterobtaining the longitude latitude date and time from theGPSon the mobile device the system can compute the normalvector at the observation point towards the celestial sphereThe marked stars on the celestial sphere above the observa-tion point can be projected to the visual plane to simulatethe starry sky seen from the earth The celestial sphere andconstellations are both static and the phenomenon of starmovement is due to the earthrsquos rotation and revolution aroundthe sun Since the normal vector at the observation pointchanges as the earth rotates the stars on the visual plane willalso rotate around the north celestial pole


North

EastWest

South

Figure 2 The celestial sphere and constellations model

22 Star Chart In order to design the universal planisphereapplicable at different latitudes the perspective projectionis used to transform the 3D coordinates of constellationson the celestial sphere to the 2D coordinates on the starchart First rotate the earth and celestial sphere (includingall constellations on it) so that the normal vector lands on the119909-119911 plane of the groundrsquos 3D coordinate systemThe groundrsquos3D coordinate system is a Cartesian coordinate system where119909-axis points to the east and 119910-axis points to the north Nextrotate the earth and the celestial sphere so that the normalvector at the observation point overlaps with the 119911-axis of the3D coordinate system The rotation matrixes for the 119910-axisand 119911-axis are specified in the following

[119877119884 (120573)] = [[[

cos120573 0 minus sin1205730 1 0

sin120573 0 cos120573]]]

[119877119885 (120572)] = [[[

cos120572 sin120572 0minus sin120572 cos120572 00 0 1

]]]

(1)

Finally use the perspective projection method to mapconstellations on the celestial sphere to the 2D star chartaccording to the userrsquos location (Figure 3) In Figure 3 997888rarrSE is aspace vector with length of one unit and its direction pointingfrom the sun to the earth and it can be used to compute thebrightness of the skyThe formulas for perspective projectionare given below

1199091015840 = 1199091 minus 119911119885119881

1199101015840 = 1199101 minus 119911119885119881

(2)

where 119885119881 is the observation point at the 119885-axis

Z

Obtain currenttime and position

Sun Earth

Y

Earth

X

Y

Earth

X

Z Z

Rotate the celestial model

Map the visibleconstellations tothe visual plane

Y

Compute the brightness of

the sky X

Compute 997888rarrSE

Figure 3 Mapping the constellations to create the star chart

The process of generating the star chart is describedin the following First the latitude at the userrsquos location isobtained from the GPS as the offset angle from the northpole of celestial sphere The star chart is generated usingthe perspective projection described above by rotating thecelestial sphere along the 119883-axis for the offset angle Inaddition the system can use the data of constellations on thecelestial sphere to create the virtual 3D starry sky and use theperspective projection to generate the northern and southernstar charts for the application at the userrsquos location Figure 4shows the star charts generated at different latitudes in theNorthern Hemisphere

23 Automatic Positioning To provide the function of posi-tioning constellations the system first obtains the azimuthand elevation angles from the electronic compass and 3-axisaccelerometer before applying the perspective projection togenerate the star chart The target constellationrsquos position canalso be located on the star chart using the same formulasand it is marked with a red circle on the star chart for easyidentificationThe formulas for positioning constellations onthe northern and southern star charts are shown in Table 1where the target constellationrsquos position in the original coor-dinate system (celestial sphere) is denoted by (119909 119910 119911) thelocal coordinate system (starry sky) is denoted by (1199091015840 1199101015840 1199111015840)and the 2D coordinate system on the star chart is denoted by(11990910158401015840 11991010158401015840) In addition 120574 stands for the offset angle (or latitude)where the user is located and 120579 represents the azimuth angleof the target constellation

According to the formulas described above the modulefor mapping from the 3D coordinate system of the celestialsphere to the 2D coordinate system on the star chart can bedeveloped Figure 5 shows the 2D coordinate system on thestar chart at the latitude of 23∘N After rotating the movableportion of the planisphere to align the date and time theazimuth and elevation angles of the target constellation canbe obtained and mapped to the correct position on the starchart (marked by a red circle) for easy identification Whenthe user makes an observation by holding the mobile devicetowards the target constellation the red circle will appearon the star chart to show its correct position Upon locating


Table 1 Formulas for positioning constellation on the universal planisphere

Original coordinate Formulas for coordinate transformation Local coordinate119909 1199091015840 = 119909 1199091015840119910 1199101015840 = 119910 times cos(120587 times 120574180) + 119911 times sin(120587 times 120574180) 1199101015840119911 1199111015840 = minus119910 times sin(120587 times 120574180) + 119911 times cos(120587 times 120574180) 1199111015840

Formulas for mapping from 3D starry sky to 2D star chart

11990910158401015840 = (1199091015840radic11990910158402 + (1199101015840 minus 11991010158400)2) times ellipse long times (90 minus 120579)90

11991010158401015840 = ((1199101015840 minus 11991010158400)radic11990910158402 + (1199101015840 minus 1199101015840

0)2) times ellipse short times (90 minus 120579)90

90∘

75∘

60∘

45∘

30∘

15∘

Figure 4 The star charts generated at different latitudes

The observed constellation is Draco

Current time 0914 1105

Current elevation is 24∘ (about 24 clenched fists)

Current azimuth is northeast (E58∘N)

Figure 5 Mapping from 3D celestial sphere to 2D star chart


Start

Main menu

Universalplanisphere

3D virtualstarry sky

Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect

Figure 6 The flowchart of online test function

the target constellation the related data (constellation namedate time azimuth angle and elevation angle) can berecorded by pressing the Record button The recorded datacan be uploaded for the teacher to check if the students havecompleted the observational assignment correctly

24 Automatic versus Manual Operation The prior knowl-edge required for conducting star observation is being ableto use a planisphere to find the target constellation Basicallythe user has to rotate the movable portion to align thecurrent date and time for the correct star chart to be shownon the planisphere The adjustment is done manually onpaper planispheres and it can be done automatically on theuniversal planisphere When doing so the system simplyobtains the current date and time through the ApplicationProgramming Interface (API) and converts them into theangle for rotating the movable portion of the planisphereThis study used the C programming language in Unity3Dto develop the manual and automatic operation functionswhich can be used to adjust the planisphere to show the starcharts for different seasons (spring summer fall and winter)and different time (evening midnight and dawn)

25 Online Test The online test function is designed to pro-vide the users with a formational evaluation Therefore theycan conduct observation using the universal planisphere andtake the online test to make sure whether they have learnedthe correct operational skills With the automatic settingmode the system adjusts the date and time automatically forthe users to observe constellation easily but they may not

know how to operate a paper planisphere when required todo so Hence the system also provides the manual operationmode such that the users have the chance to perform thealignment of date and time Using the online test functionthe teacher can check if students have learned to adjust theplanisphere and they can measure the azimuth and elevationangles of the target constellation to locate it on the star chart

The flowchart of system operation is shown in Figure 6When the user clicks the Test button on the screen the testquestions will appear at the lower part of the screen Toprevent the test question from blocking other information onthe screen the background of the test question is designedas semitransparent such that the user can also see theinformation behind it (Figure 7) After reading the testquestion the user can provide the answer by clicking theConfirmation button Then the user will receive a messageto verify if the answer is correct or not

26 Star Chart Switching As soon as the user starts thesystem the sensors will detect the userrsquos location directionand the current date and time to generate the star chart Inorder to simulate the starry sky for astronomical observationthe background color is set to black on the screenThe digitalcompass and its related information are displayed at the lowerleft corner of the screen to inform the user of his or herdirection The current date and time are shown at the upperright corner together with the functions of their adjustmentThe star chart is situated at the center taking most of thespace while the screen also displays some other informationsuch as the position (longitude and latitude) and the direction


Question 1

The movement of stars in the sky is

(a) east to west (b) south to north

(c) north to south (d) west to east

Figure 7 The test question on the universal planisphere

Figure 8 The universal planisphere switching to the southern starchart

(azimuth and elevation angles) When the user turns to facethe southern sky the planisphere will display the southernstar chart accordingly for the user to conduct observation inthe opposite direction (Figure 8)

3 Teaching Experiment

A teaching experiment has been conducted to evaluatethe learning effectiveness of students using the universalplanisphere for star observation The results are comparedwith those of using different tools (the Google Sky Mapand paper planisphere) This study randomly selected threeclasses of fifth-grade students from an elementary schoolin Taichung Taiwan as the experimental samples to formthree groups that is the experimental GroupA (23 students)the experimental Group B (25 students) and the controlGroup C (23 students) According to experimental designdifferent observational tools were used by the three groupsrespectively Group A used the universal planisphere GroupB used the Google Sky Map and Group C used the paperplanisphere for classroom teaching and star observationafter school A questionnaire survey was also conducted toinvestigate the attitudes of students after using their tools forstar observationThe variables of the teaching experiment arelisted in Table 2

Table 2 Variables in the teaching experiment

Independent variablesGroup A Universal planisphereGroup B Google Sky MapGroup C Paper planisphere

Covariance PretestDependent variables Posttest delayed posttestControl variables Teacher teaching time learning contents

The teaching experiment was conducted by following theguidelines of the ldquoAstronomical Observationrdquo learning unitin the K9 Science and Life Technology Curriculum for ele-mentary and high schools in Taiwan [17] This study adopteda nonequivalent pretest-posttest design involving differentgroups to investigate if significant differences exist amongtheir learning achievements Before the teaching activitiesall students had taken the pretest for evaluating backgroundknowledge in star observation followed by the teachingactivity using different tools for three weeks After that theposttest and questionnaire survey were conducted and thedelayed posttest was taken one month later (Figure 9) Theachievement test and questionnaire results were collected foranalyzing the learning effectiveness and attitudes of studentsafter using different tools

31 Background Knowledge According to the backgroundknowledge analysis (Figure 10) 62 of the students had theexperience of star observation before the teaching experi-mentThe percentages of students with such an experience inthe three groups are 52 (GroupA) 64 (Group B) and 70(Group C) respectively A further investigation shows thatabout one half of the experienced students had conducted starobservation within the last 6 months (Figure 11)

32 Learning Effectiveness Thepretest was taken by the threegroups of students one week before the teaching activity andits analytical results by the ANOVA show that 119865 = 008and 119875 = 092 gt 005 indicating no significant differencein the background knowledge among three groups Afterthe teaching activity the posttest was taken by the threegroups for the investigation of their learning achievementsAnalytical results by the paired sample 119905-test according to


Table 3 Results of the paired sample 119905-test for Group A

Test Average Student number Standard deviation 119879 SignificancePretest 5000 23 1610 minus747 lt0001lowastlowastlowastPosttest 7522 23 2108lowastlowastlowast119875 value less than 0001

Table 4 Results of the paired sample 119905-test for Group B


Group A

Achievement test (pretest)

Class lecture + star observation

Achievement test (posttest)

Questionnaire survey


Group B Group C

3 weeks GoogleSky Map

Paperplanisphere

Achievement test (delayed posttest)1 monthlater

15min

15min

15min

Figure 9 The flowchart of teaching experiment by three groups

the pretest and posttest have shown significant improvementin learning effectiveness for Group A (Table 3) Group B(Table 4) and Group C (Table 5) that is the universalplanisphere developed in this study can enhance studentsrsquolearning effectiveness in star observation and so can theGoogle Sky Map and paper planisphere After that theANOVA was conducted according to the pretest and posttestresults of the three groups and the analytical results haveshown that 119865 = 216 and 119875 = 012 gt 005 indicating nosignificant difference among the three groups

This study also evaluated the operational skills of studentsin using their tools to conduct star observation Accordingto the statistical results in Table 6 students in Group Aperformed much better than those in Group B because thelatter had difficulty in acquiring precise azimuth and eleva-tion angles for locating the target constellations Thereforethe universal planisphere can enhance studentsrsquo operationalskills in star observation The average score of Group A isalso higher than that of Group C but it has not achieved thestandard of significant difference

Onemonth after the teaching activity the delayed posttestwas taken by the three groups for the investigation of theirlong-term learning achievements Analytical results by thepaired sample 119905-test show no significant difference between

the posttest anddelayed posttest forGroupA (Table 7)GroupB (Table 8) and Group C (Table 9) indicating the tools usedby the three groups are effective in maintaining the learningachievement

Considering the background knowledge of experimentalsamples may be different a quasi-experimental approachusing the pretest posttest and delayed posttest design fornonequivalent groups is adopted in this study to evaluatethe learning effectiveness of students in different groupsAlthough the average score of Group A (Table 7) is lowerthan that of Group C (Table 9) the difference between thedelayed posttest and posttest forGroupA (543) is higher thanthat of Group C (minus109) Therefore the long-term learningeffectiveness (or learning retention) of using the universalplanisphere is better than that of using the paper planispherefor classroom teaching and star observation

33 Learning Attitudes Thequestionnaire survey used in thisstudy is a system satisfaction evaluation according to theusersrsquo experiences in using their tools and it was designedafter discussing with two experts in astronomy education anda science teacher The questionnaire contains 20 questionswhich are divided into four sections (5 questions in learningcontents 4 questions in system functions and interfacedesign 5 questions in learning experience and 6 questionsin studentsrsquo willingness of usage) This study adopted Likertrsquos5-point scale [18] (5 = strongly agree 4 = agree 3 = neutral2 = disagree and 1 = strongly disagree) to measure theattitudes of students after using the tools The validity ofthe questionnaire is ensured because the questions werereviewed andmodified by the teacher and experts to enhanceits correctness before performing the questionnaire surveyWhen preparing the questionnaire it was first designed asan editable form for the teacher and experts to provide theirsuggestions to establish the content validity We revised anddeleted the inappropriate questions based on their opinionsand then performed the questionnaire survey The statisticalsoftware SPSS is used to perform the reliability analysis andthe value of Cronbachrsquos alpha is 085 095 and 088 for GroupA Group B and Group C respectively showing the resultshave met the standard of high reliability

This study performed a statistical analysis on the ques-tionnaire results by the three groups as the system satisfactionsurveyThe average score (Avg) and standard deviation (SD)


Table 5 Results of the paired sample 119905-test for Group C


27

38 44

62

All students

Experience in star observation YesNo

481152

12

369

6416

16

307

70

Group A Group B Group C

Figure 10 The percentages of students with experience of star observation

10

8

6

4

2

0

Less than 6 months6 months to 1 year1 year to 2 yearsMore than 2 years

Experienced students

4

21

9

43

2

7

10

4

7

5223

167

115

219


Figure 11 Studentsrsquo experience of star observation within the last two years

of each selected item are calculated for each question tofurther understand the attitudes of students after using theirtools in star observation and the statistical results are shownin Table 10 The ANOVA is also conducted to find out thedifference of studentsrsquo attitudes in each section and eachquestion by the three groups where the question results withhigh significance (119875 lt 001) are highlighted with italic fontAlso the means of the average score and standard deviationfor all questions are also calculated and listed at the bottomThe teacher and some students have provided feedbackwhichcan be used as reference for improving the system

According to the questionnaire results the average scoreby Group A is 467 which is higher than that of Group B(407) andGroupC (424)The results show that the universalplanisphere can enhance studentsrsquo learning motivation and

interest in star observation and it can satisfy the requirementof class teaching and outdoor star observation better thanthe other two tools However the average score by GroupB is lower than that of Group C indicating that studentsmay have difficulty using the 3D tool in finding constellationsand obtaining the required informationThe ANOVA resultsshow a significant difference among the three groups onlearning contents (Table 11) interface design (Table 12)learning experiences (Table 13) and willingness of usage(Table 14)

In Table 11 the average score of Group A (475) is higherthan that of Group C (440) and Group B (399) In Table 12the average score of Group A (459) is higher than that ofGroup C (434) and Group B (402) In Table 13 the averagescore of Group A (468) is higher than that of Group C (426)


Table 6 The statistical results of operational skills

Group Student number Average Standard deviation 119865 SignificanceA 23 9174 701

1702 lt0001lowastlowastlowastB 25 8040 693C 23 8913 733lowastlowastlowast119875 value less than 0001


Test Average Student number Standard deviation 119879 SignificancePosttest 7522 23 2108 minus1641 012 gt 005Delayed posttest 8065 23 1351




Test Average Student number Standard deviation 119879 SignificancePosttest 8348 23 1449 089 038 gt 005Delayed posttest 8239 23 1075

and Group B (414) In Table 14 the average score of GroupA (475) is higher than that of Group B (410) and Group C(396) all significantly

The interview records from the teacher and students afterthe experiment are summarized in the following to supportthe validity of the questionnaire results

(1) Most students considered the system very convenientto use because they could find the location of a stareasily without looking at the compass

(2) The function of automatic positioning is helpful andit can reduce the time of identifying the star locationon the star chart

(3) Automatic mapping of elevation angle on the starchart can solve the problem of the method taughtin the textbook by raising onersquos hand to estimate theelevation angle for which it is not very accurate

(4) The system can be used in classroom to reduce thetime of teaching students how to use the planisphereto enhance the skills in star observation

4 Conclusions

Astronomical observation is an important subject in scienceand technology curriculums in elementary and high schoolsBy observing astronomical phenomena and using scientificmethods to solve the problems students can acquire correct

answers and enhance their critical thinking and problemsolving skills This study combined the augmented realitytechnology and sensor functions of GPS electronic compassand 3-axis accelerometer on mobile devices to develop amotion sensing and automatic positioning universal plani-sphere It can generate the local star chart according to theuserrsquos current position date and time By holding the mobiledevice towards the target constellation in the sky its azimuthand elevation angles can be obtained and mapped to thecorresponding position on the star chart The user can findthe target constellation by following the system instructioneasily It also contains a built-in 3D virtual starry sky so thatthe observation can be done in the classroom during daytimefor teaching applications

A teaching experiment has been conducted to evaluatestudentsrsquo learning effectiveness after using the universalplanisphere for star observation The experimental resultsindicate that there is no significant difference among thethree groups of students in their learning achievementsshowing that the universal planisphere and the other toolswere effective inmaintaining the learning achievementHow-ever studentsrsquo observational skills as well as their learningachievements have been improved significantly when usingthe universal planisphere The questionnaire results revealthat most students considered the operation of universalplanisphere and its user interface easy to use Also it can helpthem locate the target constellations quickly and made thelearning process more interesting


Table 10 The questionnaire results for the three groups

Evaluation questions Group A Group B Group CAvg SD Avg SD Avg SD

Learning contents

(1) The tool enables me to find the targetconstellationrsquos azimuth angle quickly 457 084 424 088 439 072

(2) The tool enables me to find the targetconstellationrsquos elevation angle quickly 470 070 372 094 422 100

(3) The tool enables me to verify whichconstellation a star belongs to quickly 483 049 420 071 461 066

(4) Using the tool lets me know that theNorth Star is static in the sky 474 054 396 098 470 056

(5) Using the tool lets me know that thestars are rotating from the east to the west 491 042 384 075 452 073

Interface design

(6) The tool is easy to operate 417 089 412 097 443 103(7) Operating the tool is interesting 483 039 408 081 417 111(8) The tool helps me find the constellationsquickly during outdoor observation 465 083 396 084 452 073

(9) The information on the operationinterface is easy to understand 470 064 392 091 422 104

Learning experience

(10) The tool makes the learning unit ofstar observation more interesting 474 054 424 078 435 071

(11) The tool that I am using is morehelpful than the tools used by the othergroups

478 042 436 070 413 097

(12) The tool gives me a deeper impressionon the learning contents 487 046 412 078 457 059

(13)The tool helps me complete recordingof star observation 457 079 412 093 448 059

(14) The tool can increase my motivationin outdoor star observation 443 073 388 097 378 104

Willingness of usage

(15) It is very convenient to use the tool foroutdoor star observation 487 046 408 081 274 163

(16) I like to use the tool for starobservation 470 077 432 080 391 138

(17) I will continue using the tool for starobservation in the future 483 049 404 089 426 105

(18) I will share the experience of usingthe tool with my classmates 448 095 392 104 413 118

(19) I will recommend the tool to myfamily and friends in conducting starobservation

465 089 380 100 413 110

(20) On the whole I am satisfied with theusage of the tool 496 021 444 082 461 084

Overall 467 062 407 087 424 093

Table 11 The ANOVA results of studentsrsquo attitude on learning contents




Table 12 The ANOVA results of studentsrsquo attitude on interface design


442 lt005lowastB 25 402 070C 23 434 078lowast119875 value less than 005

Table 13 The ANOVA results of studentsrsquo attitude on learning experiences


600 lt001lowastlowastB 25 414 070C 23 426 051lowastlowast119875 value less than 001

Table 14 The ANOVA results of studentsrsquo attitude on willingness of usage



The universal planisphere developed in this study pro-vides astronomical learning contents which can be usedanytime and anywhere It converts observational activitiesinto organized and meaningful knowledge and combinesspatial cognition with the establishment of correct astronom-ical knowledge and concepts The functions of mapping theazimuth and elevation angles of the target constellation inthe sky to its corresponding position on the star chart aswell as switching between the northern and southern starcharts can help students establish correct directional andspatial concepts through physical operation By using theuniversal planisphere for long-term observation they canunderstand the relation between the earthrsquos rotation andthe change of astronomical phenomena The application ofuniversal planisphere is not limited by weather conditionsor the obstruction of surrounding high buildings Besidesthe learning process can be shortened by setting differentobservation time and locations to reduce the workload ofteachers and students Therefore it is a useful tool forastronomy education in elementary and high schools

Competing Interests

The authors declare that there are no competing interestsregarding the publication of this paper

Acknowledgments

The authors wish to acknowledge the support by theMinistryof Science and Technology (MOST) Taiwan under Contractnos 103-2511-S-134-007-MY2 and 105-2514-S-134-003

References

[1] National Audubon Society Field Guide to the Night Sky AlfredA Knopf Inc New York NY USA 1991

[2] E Chaisson and S McMillan Astronomy A Beginnerrsquos Guide tothe Universe Pearson Boston Mass USA 2013

[3] M Michie ldquoFactors influencing secondary science teachers toorganize and conduct field tripsrdquo Australian Science TeachersrsquoJournal vol 44 no 4 pp 43ndash50 1998

[4] N Orion ldquoAmodel for the development and implementation offield trips as an integral part of the science curriculumrdquo SchoolScience and Mathematics vol 93 no 6 pp 325ndash331 1993

[5] K J Schoon ldquoStudentsrsquo alternative conceptions of Earth andspacerdquo Journal of Geological Education vol 40 no 3 pp 209ndash214 1992

[6] J Baxter ldquoChildrenrsquos understanding of familiar astronomicaleventsrdquo International Journal of Science Education vol 11 no5 pp 502ndash513 1989

[7] K C Trundle and R L Bell ldquoThe use of a computer simulationto promote conceptual change A Quasi-experimental StudyrdquoComputers and Education vol 54 no 4 pp 1078ndash1088 2010

[8] T De Jong and W R Van Joolingen ldquoScientific discoverylearning with computer simulations of conceptual domainsrdquoReview of Educational Research vol 68 no 2 pp 179ndash201 1998

[9] WWinn F Stahr C Sarason R Fruland P Oppenheimer andY-L Lee ldquoLearning oceanography from a computer simulationcompared with direct experience at seardquo Journal of Research inScience Teaching vol 43 no 1 pp 25ndash42 2006

[10] P-H Wu G-J Hwang L-H Su and Y-M Huang ldquoA context-aware mobile learning system for supporting cognitive appren-ticeships in nursing skills trainingrdquo Educational Technology ampSociety vol 15 no 1 pp 223ndash236 2012


[11] J Schiller and A Voisard Location-Based Services MorganKaufmann San Francisco Calif USA 2004

[12] R T Azuma ldquoA survey of augmented realityrdquo Presence Teleop-erators andVirtual Environments vol 6 no 4 pp 355ndash385 1997

[13] G Kim Designing Virtual Reality Systems The StructuredApproach Springer Heidelberg Germany 2005

[14] W Liu A D Cheok C L Mei-Ling and Y-L Theng ldquoMixedreality classroommdashlearning from entertainmentrdquo in Proceed-ings of the 2nd International Conference on Digital InteractiveMedia in Entertainment andArts (DIMEA rsquo07) pp 65ndash72ACMPerth Australia September 2007

[15] L Kerawalla R Luckin S Seljeflot and A Woolard ldquolsquoMakingit realrsquo exploring the potential of augmented reality for teachingprimary school sciencerdquo Virtual Reality vol 10 no 3 pp 163ndash174 2006

[16] Kang Hsuan Educational Publishing Group 2014 httpswwwknshcomtwIndexasp

[17] Ministry of Education K9 Science and Life Technology Curricu-lum Standards Ministry of Education Ministry of EducationTaipei Taiwan 2012

[18] R Likert ldquoA technique for the measurement of attitudesrdquoArchives of Psychology vol 22 no 140 pp 1ndash55 1932

Submit your manuscripts athttpswwwhindawicom

Computer Games Technology

International Journal of

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Distributed Sensor Networks


Advances in

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Volume 2014


ReconfigurableComputing

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Applied Computational Intelligence and Soft Computing

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Artificial Intelligence

HindawithinspPublishingthinspCorporationhttpwwwhindawicom Volumethinsp2014

Advances inSoftware EngineeringHindawi Publishing Corporationhttpwwwhindawicom Volume 2014


Electrical and Computer Engineering

Journal of

Journal of

Computer Networks and Communications


Hindawi Publishing Corporation

httpwwwhindawicom Volume 2014

Advances in

Multimedia


Biomedical Imaging


ArtificialNeural Systems

Advances in


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Computational Intelligence and Neuroscience

Industrial EngineeringJournal of


Modelling amp Simulation in EngineeringHindawi Publishing Corporation httpwwwhindawicom Volume 2014

The Scientific World JournalHindawi Publishing Corporation httpwwwhindawicom Volume 2014


Human-ComputerInteraction

Advances in

Computer EngineeringAdvances in



projectors by setting the userrsquos coordinates Google Sky Mapis an Android version of Google Sky The application enablesthe user to pinpoint the exact location of the stars planetsand other celestial objects in the night sky It can be used ona mobile device as an augmented reality application Whenpointing the mobile device at the sky the user can see detailsof 3D starry sky represented by a sky map

Michie [3] and Orion [4] considered star observation inthe night sky important and helpful for constructing astro-nomical concepts but it is difficult in practice for teachersto conduct teaching activities during night time Withoutsufficient observation and verification students can onlythink about themodels of earth and celestial sphere to explainthe starsrsquo movement in the sky due to the earthrsquos rotation andthus some common misconceptions in astronomy may stillexist [5ndash7]

The traditional planisphere has the advantages of lightweight portability easy acquisition and low price but italso has some restrictions such as applicable areas time andvisible stars It is an astronomical observation tool developedby projecting the celestial sphere and its stars towards thenorth celestial pole to form a star chart (or sky map) As aresult the constellations shown on the star chart may oftenbe distorted especially those in the southern sky To remedythis problem most planispheres provide both the northernand the southern star charts on the front and the back sidesfor easy star observation

When using a planisphere to find constellations in thenight sky the users must rotate the movable portion untilthe current date and time marked on its edge are alignedThe compass and protractor must also be used to measurethe target constellationrsquos azimuth and elevation angles Sincethe equatorial coordinate system in the celestial sphere is dif-ferent from the Cartesian coordinate system on the groundstudents may have difficulty locating a constellation on thestar chart or deciding when to switch to the northern or thesouthern star chart In addition the traditional planisphereis only applicable to a certain area (or latitude) If theobservation is to be conducted in another areawith a differentlatitude we need to use the planisphere suitable for that area

With the advance of information technology computersoftware can be applied to simulate scientific phenomenasuch as physical or chemical reactions for observation in themicroscopic world It can also reduce the amount of experi-mental variables for learners to focus on specific subjects toenable conceptual change [8 9] Nowadays mobile devicessuch as the personal digital assistance (PDA) smartphoneand tablet PC have been integrated into different educationalapplications As a result learning activities are no longerrestricted to the classroom In other words they can bedone anytime and anywhere by using any device to achieveubiquitous learning [10]

Recently the hardware of mobile devices becomes morepowerful and the built-in sensors such as the GPS elec-tronic compass and 3-axis accelerometer can provide theinformation of position time direction acceleration andso on to support the design of simulation software forapplications in different areas of education Schiller andVoisard [11] proposed the concept of context awareness by

using the GPS to obtain the userrsquos current location forproviding immediate servicesThemain objective is to satisfythe sensational requirement by updating the informationaccording to environmental changes such as local date timeposition and direction

Augmented reality (AR) is a view of the real world whereelements are augmented by computer-generated situations toenhance the perception of reality Its purpose is to incorporatevirtual objects into the real world to enhance their interac-tions with the users According to Azumarsquos [12] definitionAR is an evolution of virtual reality (VR) with the followingfeatures (1) interacting with real and virtual environments(2) providing real-time feedback and (3) necessarily being inthe 3D space In comparison VR is a technology to createan interactive environment for simulating the real worldthrough onersquos sense organs The users can see hear and feelin the created scenes as if situated in the real world andeven interact with the objects in the virtual scenes [13] ARintegrates the real world with virtual objects to increase thesense of reality in a more interactive way and it providesuseful information not directly available to enhance onersquoscomprehension in the real environments

Liu et al [14] introduced several AR systems with whichstudents can view the virtual solar system on the classroomtable and visualize the process of photosynthesis Kerawalla etal [15] combined the whiteboard projector web camera ARtechnology and 3D modeling package for students to learnabout the earth and the sun as well as the changes of dayand night It was discovered in their study that teachersrealized the advantages of using 3D images and believed thatAR can make inaccessible subject matters available to stu-dents Therefore AR can increase learnersrsquo interaction withthe real world and provide them with useful informationfor perceiving some scientific phenomena which cannot beexperienced in the real world [10]

In this study we have combined the AR technology andthe sensor functions of GPS electronic compass and 3-axisaccelerometer on mobile devices to develop a motion sens-ing and automatic positioning universal planisphere It cancreate local star charts according to the current positiondate and time and help the user locate constellations onthe star chart easily through motion sensing operation Byholding the mobile device towards the target constellation inthe sky the azimuth and elevation angles are mapped to thecorresponding position on the star chart With the functionof searching constellations the user can find the targetconstellation easily by following the instruction By settingthe observation date time and latitude the user can seethe change on the star chart to understand that constellationsseen at different time in different seasons or at differentlatitudes are also different

The system can shorten the learning process by changingthe setting for observationWith the built-in virtual 3D starrysky it can solve the problem of being unable to observe starsdue to bad weather conditions or obstruction by surroundinghigh buildings In addition the physical operation can makea deeper impression on students enabling them to storethe acquired knowledge in long-term memory The systemcombines observational activities with physical operation





2 System Design

















North

EastWest

South



[119877119884 (120573)] = [[[

cos120573 0 minus sin1205730 1 0

sin120573 0 cos120573]]]

[119877119885 (120572)] = [[[


]]]

(1)


1199091015840 = 1199091 minus 119911119885119881

1199101015840 = 1199101 minus 119911119885119881

(2)


Z


Sun Earth

Y

Earth

X

Y

Earth

X

Z Z



Y


the sky X













90∘

75∘

60∘

45∘

30∘

15∘








Start

Main menu



Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect









Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in







2 System Design

















North

EastWest

South



[119877119884 (120573)] = [[[

cos120573 0 minus sin1205730 1 0

sin120573 0 cos120573]]]

[119877119885 (120572)] = [[[


]]]

(1)


1199091015840 = 1199091 minus 119911119885119881

1199101015840 = 1199101 minus 119911119885119881

(2)


Z


Sun Earth

Y

Earth

X

Y

Earth

X

Z Z



Y


the sky X













90∘

75∘

60∘

45∘

30∘

15∘








Start

Main menu



Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect









Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in




North

EastWest

South



[119877119884 (120573)] = [[[

cos120573 0 minus sin1205730 1 0

sin120573 0 cos120573]]]

[119877119885 (120572)] = [[[


]]]

(1)


1199091015840 = 1199091 minus 119911119885119881

1199101015840 = 1199101 minus 119911119885119881

(2)


Z


Sun Earth

Y

Earth

X

Y

Earth

X

Z Z



Y


the sky X













90∘

75∘

60∘

45∘

30∘

15∘








Start

Main menu



Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect









Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in










90∘

75∘

60∘

45∘

30∘

15∘








Start

Main menu



Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect









Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in




Start

Main menu



Observation mode

Real-timedisplay

Adjustdatetime

Zoom inZoom out

Azimuthelevation

Timeinformation

Enlargenormal

Testmodule

Uploadtest result

3-axisaccelerometer

Electroniccompass

Adjust display

Test resultCorrect

Incorrect









Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in




Question 1




















Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in








Group A






Group B Group C


Paperplanisphere


15min

15min

15min












27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in






27

38 44

62

All students


481152

12

369

6416

16

307

70



10

8

6

4

2

0



4

21

9

43

2

7

10

4

7

5223

167

115

219























4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in



















4 Conclusions







Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in






Learning contents






Interface design



Learning experience



478 042 436 070 413 097










465 089 380 100 413 110


Overall 467 062 407 087 424 093















Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in














Competing Interests


Acknowledgments


References



























Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in



















Advances in

FuzzySystems


Volume 2014












Journal of

Journal of





Advances in

Multimedia


Biomedical Imaging



Advances in


RoboticsJournal of










Advances in



Development of a Motion Sensing and Automatic Positioning Universal Planisphere...

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Transcript of Development of a Motion Sensing and Automatic Positioning Universal Planisphere...