standards for networked knowledge organisation systems ron davies [email protected] european library...
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Standards for networked knowledge organisation
systems
European Library Automation GroupBucharest, 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
• 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
BS 8723
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
bétail
gros bétail
boeuf cheval horsescattle
livestock
French English
bétail
gros bétail
boeuf cheval horsescattle
livestock
?
Multilingual thesaurus - Solution A
bétail
gros bétail
boeuf cheval horsescattle
livestock
Multilingual thesaurus- Solution B
bétail
gros bétail
boeuf cheval horsescattle
livestock
Asymmetrical thesaurus / mapping
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
• 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
Goals for communication standards
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
economic aid
skos:prefLabel
Class (Concept)
Property
Literal
subject
predicate
object
developmentaid
economic aid
skos:prefLabel
skos:broader
skos:prefLabel
developmentaid
economic aid
skos:prefLabel
financialaid
financialgrants
skos:broader
skos:prefLabel
skos:prefLabel
skos:prefLabel
skos:related
skos:narrower
developmentaid
economic aid
skos:prefLabeleconomic assistance
skos:altLabel
financialaid
financialgrants
skos:broader
skos:prefLabel
skos:prefLabel
skos:prefLabel
skos:related
skos:narrower
Use for aid at international level.
skos:scopeNote
developmentaid
economic aid
skos:prefLabeleconomic assistance
skos:altLabel
financialaid
financialgrants
skos:broader
skos:prefLabel
skos:prefLabel
skos:prefLabel
skos:related
skos:narrower
Use for aid at international level.
skos:scopeNote
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
developmentaid
economic aid
skos:prefLabeleconomic assistance
skos:altLabel
financialaid
financialgrants
skos:broader
skos:prefLabel
skos:prefLabel
skos:prefLabel
skos:related
skos:narrower
Use for aid at international level.
skos:scopeNote
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
xml-lang=“en”
aide économique
aide financièrexml-lang=“en”
skos:altLabel
skos:prefLabel
xml-lang=“fr”
xml-lang=“fr”
<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 Guidelineshttp://www.ifla.org/VII/s29/pubs/Draft-multilingualthesauri.pdf
• ANSI Z39.19http://www.niso.org/standards/standard_detail.cfm?std_id=814
• BS 8723http://www.bsonline.bsi-global.com/server/index.jsp
• SKOShttp://www.w3.org/2004/02/skos/core/
• 5th European NKOS Workshop (Sept. 21, 2006)
http://www.ukoln.ac.uk/nkos/nkos2006/