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Standards for networked knowledge organisation systems. Ron Davies ron@rondavies.be European Library Automation Group Bucharest, April 2006. A critical role. Future of the web depends on distributed services interoperating using semantic descriptions
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Standards for networked knowledge organisation systems Ron Davies ron@rondavies.be European Library Automation Group Bucharest, April 2006
A critical role • Future of the web depends on distributed services interoperating using semantic descriptions • Future of the library depends on providing integrated access to dispersed and disparate resources • Intelligent, integrated subject access needs networked knowledge organisation systems
NKOS • Networked Knowledge Organisation Systems • Thesauri, classification schemes, subject heading schemes, taxonomies • Network-accessible to human or machine clients • Available to a variety of different applications
What can an NKOS do? • Support discovery (browsing) • Translate a search • Natural language -> controlled vocabulary • Spoken languages (English -> French) • Indexing languages (AGROVOC -> LCSH) • Enrich a search (expand, refine) • Display results in a meaningful way • Automatic classification /categorisation Without standards, each vocabulary means developing a new service
Levels of standards Content standards Communication (format) standards Service (protocol) standards
New content standards • IFLA Guidelines for Multilingual Thesauri (2005) • ANSI / NISO Guidelines for Monolingual Controlled Vocabularies Z39.19 - 2005 • British Standard BS 8723 Structured Vocabularies For Information Retrieval (2005-2006)
BS 8723 • Structured vocabularies = Knowledge organisation systems • Purpose • Update ISO and BS standards (1985) • Update from print format to networked, electronic applications • Provide guidance on electronic management and use • Integrate mono- and multi-lingual standards
BS 8723 • Pt 1 - Definitions, symbols, abbreviations • Pt 2 - Thesauri • Pt 3 - Vocabularies other than thesauri • Pt 4 - Interoperability between vocabularies • Pt 5 - Interoperability between components of IR systems
Equivalence • Re-examine notion of equivalence • Synonyms or quasi-synonyms in a monolingual context • In a multilingual context • In mapping one vocabulary to another (classifications, filing plans, taxonomies, subject headings, ontologies)
Symmetry • Traditional symmetrical multilingual thesaurus • Each concept must have an equivalent in each language --> forced meanings, loan words, coined words or neologisms • Asymmetrical multilingual thesaurus • Different numbers of terms/concepts in different languages • No longer enforce one-to-one correspondence between languages BUT more complex for systems to use
French English livestock bétail gros bétail horses boeuf cheval cattle
Multilingual thesaurus - Solution A livestock bétail ? gros bétail horses boeuf cheval cattle
Multilingual thesaurus- Solution B livestock bétail gros bétail horses boeuf cheval cattle
Asymmetrical thesaurus / mapping livestock bétail gros bétail horses boeuf cheval cattle
Mapping • Establishing equivalences between one structured vocabulary and another • UMLS, MACS (Clavel, Landry), HILT • Similar complex, partial, inexact, hierarchical equivalences • Information systems will need to support these equivalences
Goals for communication standards • IR system interoperability • Ability of a search/indexing system to make use of more than one KOS in a networked environment • Management of structured vocabularies • Translation / adaptation • Migration • From one management system to another • From management system to IR application
Communication standards • Tend to be vocabulary-, application- or protocol- specific • Tag/data format • ISO 2709 / MARC Authorities format • Institution-specific XML • VocML • Alexandria Digital Library Protocol • ZThes (Z39.50 Profile) • VDEX • SKOS Core (Semantic web)
Semantic Web Application Development (SWAD) • Semantic web activity • EU- and W3C- sponsored research • Simple Knowledge Organisation System (SKOS) Core • Make existing KOS (thesauri, classifications, subject heading lists) usable in framework of Semantic Web • Uses Semantic Web standards = XML/RDF (not Topic Maps)
SKOS • SKOS Core (version 2.0) • SKOS Core Vocabulary • A set of RDF classes and properties • SKOS Core Guide • Identify concepts via URI • Describe concepts via RDF • Publish concepts via an RDF document available from HTTP or RDF server
Simple example economic aid fr aide économiquees ayuda ecónomicaSN Use for aid at international level.UF economic assistanceBT development aidNT financial aidRT financial grants
Literal economic aid object Property skos:prefLabel predicate Class (Concept) subject
developmentaid economic aid skos:prefLabel skos:prefLabel skos:broader
developmentaid economic aid skos:prefLabel skos:prefLabel skos:broader financialaid skos:narrower skos:prefLabel skos:related financialgrants skos:prefLabel
developmentaid economic aid economic assistance skos:prefLabel skos:prefLabel skos:altLabel skos:broader financialaid skos:narrower skos:prefLabel skos:related financialgrants skos:scopeNote skos:prefLabel Use for aid at international level.
developmentaid economic aid economic assistance skos:prefLabel skos:prefLabel xml-lang=“en” xml-lang=“en” skos:altLabel xml-lang=“en” skos:broader financialaid skos:narrower skos:prefLabel xml-lang=“en” skos:related financialgrants skos:scopeNote xml-lang=“en” skos:prefLabel xml-lang=“en” Use for aid at international level.
developmentaid economic aid economic assistance skos:prefLabel skos:prefLabel xml-lang=“en” xml-lang=“en” skos:altLabel xml-lang=“en” skos:broader financialaid skos:prefLabel skos:narrower xml-lang=“fr” skos:prefLabel aide économique xml-lang=“en” skos:altLabel skos:related xml-lang=“fr” financialgrants skos:scopeNote aide financière xml-lang=“en” skos:prefLabel xml-lang=“en” Use for aid at international level.
<rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:skos="http://www.w3.org/2004/02/skos/core#"><rdf:type rdf:resource="http://www.w3.org/2004/02/skos/core#Concept"/> <skos:Concept rdf:about=" http://foobar.org/thes/7021"> <skos:prefLabel xml-lang=“en”>economic aid</skos:prefLabel> <skos:altLabel xml-lang=“en”>economic assistance</skos:altLabel> <skos:prefLabel xml-lang=“fr”>aide économique</skos:prefLabel> <skos:altLabel xml-lang=“fr”>aide financière</skos:altLabel> <skos:scopeNote xml-lang=“en”>Use for aid at international level.</skos:scopeNote> <skos:broader rdf:resource=" http://foobar.org/thes/8013" /> <skos:narrower rdf:resource=" http://foobar.org/thes/3024" /> <skos:related rdf:resource=" http://foobar.org/thes/3024" /> </skos:Concept>
Other properties / classes • skos:definition / skos:historyNote / skos:editorialNote /skos:changeNote • skos:hiddenLabel • skos:Collection / skos:member • skos:hasTopConcept • skos:ConceptScheme / skos:inScheme • Properties can be extended (e.g. for specific types of BT/NT relationship or types of notes)
SKOS issues • Ontology approach doesn’t allow for all thesaurus information • Information about non-preferred terms • Equivalences between non-preferred terms • For web interoperability, not for management • RDF / Topic Maps - the Betamax/VHS of subject access? • Versioning / Mapping / Take up / Protocols
BS 8723 • Part 5 Interoperability of structured vocabulary components of an IR system • Aims to list and evaluate different format and service approaches to thesaurus interoperability • Input from a wide number of people expert in a variety of technologies • For more information, contact Ron Davies ron (a) rondavies.be
Conclusion • Most interesting time for structured vocabularies since the 1960s • Urgent need for broad-based standards to facilitate network interoperability in information retrieval • Important progress in standards though more work to be done
For more information • IFLA Guidelines http://www.ifla.org/VII/s29/pubs/Draft-multilingualthesauri.pdf • ANSI Z39.19 http://www.niso.org/standards/standard_detail.cfm?std_id=814 • BS 8723 http://www.bsonline.bsi-global.com/server/index.jsp • SKOS http://www.w3.org/2004/02/skos/core/ • 5th European NKOS Workshop (Sept. 21, 2006) http://www.ukoln.ac.uk/nkos/nkos2006/