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RDF and Metadata Andy Powell UKOLN, University of Bath UKOLN is funded by the Library and Information Commission,

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Presentation on theme: "RDF and Metadata Andy Powell UKOLN, University of Bath UKOLN is funded by the Library and Information Commission,"— Presentation transcript:

1 RDF and Metadata Andy Powell UKOLN, University of Bath UKOLN is funded by the Library and Information Commission, the Joint Information Systems Committee of the Higher Education Funding Councils, as well as by project funding from the JISC and the European Union. UKOLN also receives support from the University of Bath where it is based.

2 NDISD99 - May Metadata applications resource discovery site-maps content rating e-commerce, rights management collaboration privacy Web-site management W3Cs Resource Description Framework (RDF) provides a generic metadata architecture

3 NDISD99 - May Presentation outline... what is RDF? model syntax metadata schemas what is the Dublin Core? Dublin Core in RDF some examples current status of RDF conclusions

4 NDISD99 - May What is metadata? data about data? information about resources? structured information about stuff stuff includes Web resources, books, museum artifacts, CDs, abstract works, pieces of music… machine readable supports variety of usage scenarios

5 NDISD99 - May What is RDF? Resource Description Framework Input from various communities Platform for Internet Content Selection (PICS) Web Collections (Site maps, MCF) Libraries, museums, archives (DC) Privacy (P3P) W3C Metadata Activity Model and Syntax WG Schema WG Interoperability of metadata semantics, structure, syntax

6 NDISD99 - May RDF - the model simple triple-based model arc-node diagrams resources represented by nodes with URI property is some attribute of the resource value can be literal or further statement(s) a collection of statements about a resource forms a description resource property value statement

7 NDISD99 - May RDF - simple example or, in plain English… Andy Powell is the author of the resource identified by author Andy Powell

8 NDISD99 - May RDF - structured example provide structured metadata by replacing simple text value by another node. author Andy name Address

9 NDISD99 - May RDF - reification possible to make statements about statements process known as reification cost £ validUntil

10 NDISD99 - May RDF - serialisation syntax 2 XML serialisation syntaxes allows us to write down the RDF model in a way that can be processed by machines title The UKOLN Metadata Home Page The UKOLN Metadata Home Page

11 NDISD99 - May RDF - serialisation syntax title The UKOLN Metadata Home Page The UKOLN Metadata Home Page

12 NDISD99 - May RDF - serialisation syntax title The UKOLN Metadata Home Page The UKOLN Metadata Home Page

13 NDISD99 - May The UKOLN Metadata Home Page RDF - serialisation syntax title The UKOLN Metadata Home Page

14 NDISD99 - May RDF - multiple properties The UKOLN Metadata Home Page Dublin Core, MARC, TEI, IAFA, … Start of several Web pages about metadata Here is an example of a description with multiple properties:

15 NDISD99 - May RDF - review what does title mean? is your title the same as my title? So, weve looked at simple arc-node diagrams and serialisation in XML… but...

16 NDISD99 - May RDF - namespaces XML namespaces are used to uniquely identify each RDF property namespaces prefix the property separated by :, e.g. some title each namespace has URI associated with it to ensure uniqueness

17 NDISD99 - May RDF - schemas RDF Schemas define: available properties within a particular metadata system structure allowable values semantics relationships between different schemas an RDF Schema Specification is currently being finalised by the W3C namespace URIs may point to schema definitions

18 NDISD99 - May What is the Dublin Core? 15 element metadata set primarily resource discovery primarily Web-based document-like objects emphasis on semantics widespread consensus several syntaxes currently early example of an RDF schema

19 NDISD99 - May DC history... workshop series - DC-1 to DC-5 discussion list DC Policy Advisory Committee DC Technical Advisory Committee series of RFCs in preparation submission to NISO (…ISO)

20 NDISD99 - May Dublin Core - elements Title Subject Description Creator Publisher Contributor Date Type Format Identifier Source Language Relation Coverage Rights 15 element core metadata set

21 NDISD99 - May Qualified DC DC semantics are defined very broadly. Possible to: refine the meaning of elements using type: Relation TYPE=IsPartOf associate value with externally defined scheme: Subject SCHEME=LCSH Date SCHEME=ISO8601 indicate language of value Title LANGUAGE=en

22 NDISD99 - May How is DC currently used? Embedded into HTML Web pages tag limited functionality no structure HTML version 4.0 support for SCHEME and LANG syntax for qualified DC in tags not well established

23 NDISD99 - May DC in HTML UKOLN Home Page...

24 NDISD99 - May DC in RDF The UKOLN Metadata Home Page dc:title The UKOLN Metadata Home Page

25 NDISD99 - May DC in RDF The UKOLN Metadata Home Page dc:title The UKOLN Metadata Home Page

26 NDISD99 - May DC in RDF The UKOLN Metadata Home Page dc:title The UKOLN Metadata Home Page

27 NDISD99 - May DC in RDF The UKOLN Metadata Home Page dc:title The UKOLN Metadata Home Page

28 NDISD99 - May DC in RDF in HTML ! cant embed standard RDF/XML syntax because content not hidden embed using abbreviated syntax embed at end of HTML section if this isnt possible to external RDF file, e.g.

29 NDISD99 - May DC in RDF - abbreviated The UKOLN Metadata Home Page dc:title

30 NDISD99 - May RDF - current status RDF Specification - W3C Recommendation RDF Schema Spec - Proposed Recommendation Some support for RDF in Mozilla RDF toolkits/parsers under development Several RDF editors available, e.g. DC-dot, UKOLN Reggie, DSTC Various other RDF-based services

31 NDISD99 - May Conclusions RDF is a general-purpose framework RDF provides structured, machine- understandable metadata for the Web metadata vocabularies can be developed without central coordination RDF Schemas describe the meaning of each property name Dublin Core is one of the key RDF Schemas signed RDF is the basis for trust

32 NDISD99 - May Further information Resource Description Framework (RDF) Model and Syntax Specification Resource Description Framework (RDF) Schema Specification Dublin Core DC-Datamodel home INDECS DC-dot Reggie SiRPAC Representing vCard v3.0 in RDF


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