Slide 1Explain LiteONE -2 OPAC Network in Europe Explain Lite Research and Development activity in...

Explain Lite ONE -2 OPAC Network in Europe Slide 1

Explain Lite

• Research and Development activity in the ONE-2 Project - OPAC Network in Europe 2


Background• Project partners undertook significant research and

development into the full Z39.50 Explain service, 1995 - 1997

• Created a fully working freeware server explain module that can be integrated into server applications - called “the PED”

• Integrated explain into the freeware “ICONE” Z39.50 client

• Several project partners added Explain to their targets

• project liaised with ZIG and Explain test-bed


Conclusions of Explain work• Explain in server requires significant development

effort - not just the PDU support, but the EXP database and necessary administration components

• Explain in server requires an element of data administration/maintenance:– some data can be auto-generated, eg, database size

– other data requires administration effort for the data to be kept up to date, eg, contact details


Conclusions of Explain work• Explain in client requires significant

development work:– EXP search and retrieval– possible cache arrangements– dynamic configuration– dealing with cases where perhaps only some

explain aspects are supported

• Client needs to issue an explain query to see if the server supports explain or not


Conclusions of Explain work• Explain “ is probably the right way to do it” but:

– its never been profiled

– very little take up in either clients or servers (explain test-bed had about 14 participants)

– clients always need a fallback configuration anyway

– very little interest shown since test bed ended

– would changing / updating the model to different record formats or profiling etc encourage development support ?

• This still leaves the requirement for client developers to ascertain server search and retrieval parameters.


Explain - Lite:• Requirements:

– to harmonize effort of a server administrator– to provide only essential components for search

and retrieval– to retain the optional provision - Explain Lite

info is only provided if requested– ONE 2 project is researching how the data can

be otherwise used, eg:• proxy servers

• client configuration


Design Approach• ONE-2 project:

– did not want to do this in ASN.1

– did not want to re-visit or change the current model

– did want an approach that was flexible

– decided to craft in XML

– decided to craft onto the Init service

– is aware that there are potential limitations for use, eg, may not be best suited on Init when there are many databases on a server, but:

• in this case it could be useful in describing such data via web pages.


Content• Contact information• Search attributes• Browse attributes• Database names• Record formats and element set names• Linkages to other related pages, eg,

– same content in other languages

• Data of last update - useful to avoid possible unnecessary re-cache operations in the client


Flexibility• Use of XML has enabled rapid application

development and ease of changes/tuning• Same XML can also be used :

– in client configuration files

– in proxy applications

• Content can be easily parsed/verified with XML parser tools

• Can use XSL to give presentation on Web pages


Why this approach:• Minimum work is necessary at the PDU level for

implementation• Takes advantages of current skills base• Enables administrators to harmonize explain lite

with any descriptive configuration details in Web pages

• Aligns with increasing use of XML with Z39.50• May be a first step to promote implementers to

think further on the full explain model• ….. This is _easy_ to do !


Current Status• Design is 99% ready

• ONE-2 partners are implementing in their systems

• ONE-2 project has a 7 month trial phase in 2001, and the opportunity to test and try

• Design is open for anyone to have a play, we will notify ZIG when servers can be tested


Example• XML example:

– http://www.bibsys.no/z/bibz.xml– http://www.bibsys.no/z/spirz.xml

• DTD:– http://www.bibsys.no/z/explainlite.dtd

• XSL Style example:– http://www.bibsys.no/z/lite1.xsl


Example XML

</description><records> <elementsetname>Full</elementsetname> <recordsyntax>USMARC</recordsyntax> <recordsyntax>NORMARC</recordsyntax> <recordsyntax>SUTRS</recordsyntax></records><records> <elementsetname>Brief</elementsetname> <recordsyntax>USMARC</recordsyntax> <recordsyntax>NORMARC</recordsyntax> <recordsyntax>SUTRS</recordsyntax></records><retrieval> <attributeset>BIB-1</attributeset><searchattributes> <searchname>Personal name</searchname> <values> <use>1</use> <structure>1</structure> <structure>2</structure> <structure>6</structure> <structure>101</structure> </values></searchattributes>


… and on display:

Slide 1Explain LiteONE -2 OPAC Network in Europe Explain Lite Research and Development activity in...

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