VoID: Metadata for RDF Datasets

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VoID: Metadata for RDF Datasets

  1. 1. Digital Enterprise Research Institute www.deri.ie VoID – Metadata for RDF datasets Richard Cyganiak, Linked Data Research Centre Stefan.Decker@deri.org http://www.StefanDecker.org/ Copyright 2010 Digital Enterprise Research Institute. All rights reserved.
  2. 2. Digital Enterprise Research Institute www.deri.ie VoID Vocabulary of Interlinked Datasets
  3. 3. W3C Interest Group noteDigital Enterprise Research Institute www.deri.ie http://www.w3.org/TR/void/ 3
  4. 4. Digital Enterprise Research Institute www.deri.ie “What business-related datasets are in the LOD Cloud?” “Which datasets deal with politics and transparency in the EU?” “We have some DERI data. What could we link it to?”
  5. 5. Read …Digital Enterprise Research Institute www.deri.ie http://esw.w3.org/TaskForces/CommunityProjects/LinkingOpenData/DataSets
  6. 6. Click …Digital Enterprise Research Institute www.deri.ie
  7. 7. Sindice …Digital Enterprise Research Institute www.deri.ie
  8. 8. Google …Digital Enterprise Research Institute www.deri.ie
  9. 9. And even if we find a dataset …Digital Enterprise Research Institute www.deri.ie
  10. 10. Standard questionsDigital Enterprise Research Institute www.deri.ie  What kind of data is there?  Examples?  Is it up to date?  Who publishes it?  Where is the SPARQL endpoint?  Is there a download?  How big is it?  What’s the license?
  11. 11. DatasetsDigital Enterprise Research Institute www.deri.ie  A dataset is a set of RDF triples that are published, maintained or aggregated by a single provider
  12. 12. LinksetsDigital Enterprise Research Institute www.deri.ie  An RDF link is an RDF triple whose subject and object are described in different datasets  A linksetis a collection of such RDF links between two datasets
  13. 13. voiD schemaDigital Enterprise Research Institute www.deri.ie Statistics Interlinking General metadata
  14. 14. General dataset metadataDigital Enterprise Research Institute www.deri.ie  Leveraging DublinCore:  Dataset homepage  Publisher  Title and description  Categorisation  Licensing  Technical features
  15. 15. General dataset metadataDigital Enterprise Research Institute www.deri.ie
  16. 16. Access metadataDigital Enterprise Research Institute www.deri.ie  How to access the actual RDF triples:  SPARQL endpoints  RDF data dumps  Root resources  URI lookup endpoints  OpenSearch description documents
  17. 17. Access metadataDigital Enterprise Research Institute www.deri.ie
  18. 18. Structural metadataDigital Enterprise Research Institute www.deri.ie  High-level information about schema and internal structure of a dataset  Can be helpful when exploring or querying datasets  Example resources  Patterns for resource URIs  Vocabularies  Dataset partitions  Statistics
  19. 19. Structural metadataDigital Enterprise Research Institute www.deri.ie
  20. 20. Describing linksetsDigital Enterprise Research Institute www.deri.ie
  21. 21. Describing linksetsDigital Enterprise Research Institute www.deri.ie
  22. 22. Digital Enterprise Research Institute www.deri.ie Deployment and Discovery
  23. 23. Alongside a datasetDigital Enterprise Research Institute www.deri.ie
  24. 24. Digital Enterprise Research Institute www.deri.ie  Publishing aVoIDfile alongside a dataset  Turtle  RDFa  Discovery (well-known URI)  http://yoursite/.well-known/void
  25. 25. UsersDigital Enterprise Research Institute www.deri.ie  Used by DBpedia, OpenLink, data.gov.uk, …  30% of LOD datasets have VoID metadata  The entire LOD Cloud described inVoID:  semantic.ckan.net
  26. 26. ApplicationsDigital Enterprise Research Institute www.deri.ie 26
  27. 27. Ed Summers’ LOD GraphDigital Enterprise Research Institute www.deri.ie
  28. 28. SummaryDigital Enterprise Research Institute www.deri.ie  Metadata for linked datasets  For the 4-5 star datasets  W3C Interest Group note (VoID 2) http://www.w3.org/TR/void/  Leverages Dublin Core, FOAF, etc.  Used by DBpedia, OpenLink, data.gov.uk, …  Used to generate the LOD Cloud diagram  The entire LOD Cloud described in VoID:  semantic.ckan.net 28

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