SKOS and Other W3C Vocabulary Related Activities

1
SKOS and Other W3C Vocabulary Related Activities

• Gail Hodge
• Information International Assoc.
• NKOS Workshop
• Denver, CO
• June 10, 2005

2
Acknowledgements

• Based on
• Presentation by Alistair Miles of the Rutherford
  Laboratory at the OpenForum on Metadata
  Registries, April 2005.
• Input from Joel Sachs, Univ. of Maryland
  Baltimore Co. and the SPIRE Project.
• Documents from the SKOS Web site.

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What is the Semantic Web?

• Semantic Web grand vision
• "The Semantic Web is an extension of the current
  web in which information is given well-defined
  meaning, better enabling computers and people to
  work in cooperation."
• in practice
• The Semantic Web provides a common technological
  framework (i.e. URI, RDF, SPARQL, RDFS, OWL )
  that allows data to be shared and reused across
  application, enterprise, and community
  boundaries.
• Successful sharing and reuse requires an
  understanding of meaning.

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Relevant W3C Semantic Web Activities

• Best Practices and Deployment Working Group
• Chartered through January 31, 2006
• Working drafts
• SKOS core related documents (vocabulary
  specification guide etc.)
• SKOS Mapping Vocabulary
• API for terminology web services
• XML Schema Datatypes in RDF and OWL
• Defining N-ary relationships on the semantic web
  Use with individuals
• Web Service Description Working Group 2
• Chartered through January, 2006
• Working Drafts
• WSDL 2.0
• SOAP 1.1 Binding

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Relevant Activities, contd.

• RDF Data Access Working Group
• Chartered (roughly) till end of 2005
• Working Drafts
• SPARQL Query Language for RDF
• SPARQL Variable Binding Results XML Format
• SPARQL Protocol for RDF
• (written in WSDL 2.0)
• Web-Ontology Working Group (closed)
• Recommendations
• The whole OWL family of documents (language
  overview language guide language reference use
  cases etc.)

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SKOS Core

• An extensible RDF language for describing
  concepts and concept schemes
• a concept scheme is a set of concepts,
  optionally including relationships between
  concepts.
• i.e. controlled vocabularies, thesauri,
  classification schemes, glossaries, subject
  heading systems, terminologies
• e.g. AAT, DDC, AGROVOC

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OWL vs. SKOS Core

• OWL is the language of the Semantic Web.
• Why do you need SKOS if you have OWL?
• SKOS Core
• more flexible, less demanding approach to
  modelling concepts
• better suited to types of KOS mentioned
• requiring little or no remodelling to express
  in RDF
• therefore low cost, while adding value through
  simple benefits of RDF/semantic web approach.

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Basic SKOS Vocabulary

• SkosConcept Class (this resource is a concept)
• Lexical Labelling Properties (associate concept
  with a name)
• Symbolic Labelling (associate concept with
  symbols)
• Semantic Relationship Properties (relationships
  between concepts)
• Documentation Properties (definitions and change
  notes)
• Subject Indexing (connecting an information
  resource to terminology, dcsubject)

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Traditional Thesaurus to SKOS Mapping

• Concept gets a URI, not a name
• Lexical Labeling names (not new concepts)
• SkosprefLabel
• SkosaltLabel (Used For)
• Relationship Labeling between concepts
• Skosbroader
• Skosnarrower
• Skosrelated
• Documentation such as Scope notes
• SkosscopeNote
• Skos definition

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RDF Graph Representation
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SKOS Status

• Development history
• Initiated by Semantic Web Advanced Development
  for Europe project (SWAD-E) in 2003
• Public development process and open developer
  community
• Driven by W3C Semantic Web Best Practices and
  Deployment Working Group since 2004
• SKOS Core status
• 1st Public Working Draft May, 2005
• RDF Vocabulary and Guidelines for KOS Conversion
  also available
• Comments requested by end of June 2005
• Standardization goal
• W3C Working Group Note
• W3C Recommendation track?

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Open Issues Understanding the Limitations of SKOS

• Difference between SKOS Core and other RDF
  applications because modeling concepts adds
  another level of indirection
• Properties are properties of the concept and not
  necessarily of the real-world thing
• If two conceptual resources share the same
  meaning they are not necessarily the same
  resource
• Meaning from definitions versus semantic context
  (relationships, labels, etc.)
• Concept scheme versioning use of SkosinScheme
  property
• HTTP URIs for Concepts (this is an open question
  for the Technical Architecture Group)

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SKOS Resources

• SKOS Home Page
• http//www.w3.org/2004/02/skos/
• SKOS Core Guide
• SKOS Core Vocabulary
• Quick Guide to Publishing a Thesaurus on the
  Semantic Web
• SKOS Mailing List
• mailtopublic-esw-thes_at_w3.org
• http//lists.w3.org/Archives/Public/public-esw-the
  s/

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RDF/XML Using the UK Archival Thesaurus

• ltrdfRDF
• xmlsrdfhttp//www.w3.org/1999/02/22-rdf-synta
  x-ns
• xmlnsrdfshttp//www.w3.org/2000/01/rdf-schema
  
• xmlnsskoshttp//www.w3.org/2004/02/skos/core
  gt
• ltskosConcept rdfabouthttp//www.ukat.org.uk/t
  hesaurus/concept/1750gt
• ltskosprefLabelgtEconomic cooperationlt/skosprefL
  abelgt
• ltskosaltLabelgtEconomic co-operationlt/skosaltLa
  belgt
• ltskosscopeNotegtIncludes cooperative measures
  in banking, trade, industry, etc. between and
  among countries.lt/skosscopeNotegt
• ltskosbroader rdfresourcehttp//www.ukat.org.u
  k/thesaurus/concept/
• 3000gt Economic policy
• skosnarrower rdfresourcehttp//www.ukat.org.u
  k/thesaurus/concept/
• 3022gt industrial cooperation
• ltskosnarrower rdfresourcehttp//www.ukat.org.
  uk/thesaurus/
• concept/3500gt Economic integration
• ltskosinScheme rdf resourcehttp//www.ukat.org
  .uk/thesaurus/gt
• lt/skosConceptgt
• lt/rdfRDFgt