RDFauthor (EKAW)

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My presentation on RDFauthor at EKAW2010, Lisbon. For more information on RDFauthor visit http://aksw.org/Projects/RDFauthor; for the code visit http://code.google.com/p/rdfauthor/.

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RDFauthor (EKAW)

  1. 1. Employing RDFa for Collaborative Knowledge Engineering Sebastian Tramp, Norman Heino, Sören Auer, Philipp Frischmuth Agile Knowledge Engineering and Semantic Web (AKSW) – Universität Leipzig
  2. 2. Knowledge Engineering on the Web • HTML forms are unaware of semantics • HTML5 allows pre- defined input state semantics • Sophisticated user support requires definable semantics! Currently: hard-wired semantics, abuse of class attributes
  3. 3. RDFa • Annotating XML documents with RDF • Human and machine- readable • MVC – declare view in model language Images: http://www.w3.org/TR/xhtml-rdfa-primer/
  4. 4. Knowledge Engineering by Employing RDFa • RDFa page, updatable knowledge store HTTP Web XHTML • + Edit "Intelligent" editing Server + RDF Store RDFa components (widgets) SPARQL/Update • Supporting the user
  5. 5. Requirements for RDFauthor • Editing data chunks • Standards-based update • Light-weight addition • Extensible widget pool • Multiple sources
  6. 6. Named Graphs and Provenance Extending RDFa • Data source for each triple • Update endpoint (SPARQL/Update) • Query endpoint for reference (SPARQL)
  7. 7. RDFa Example <p about="http://sebastian.tramp.name" typeof="foaf:Person"> <img rel="foaf:depiction" src="http://aksw.org/img/…" /> <strong property="foaf:name">Sebastian Tramp</strong> </p>
  8. 8. RDFa Example from Two Sources <p about="http://sebastian.tramp.name" typeof="foaf:Person"> <img rel="foaf:depiction" src="http://aksw.org/img/…" /> <strong property="foaf:name">Sebastian Tramp</strong> </p> <p about="http://www2009.eprints.org/63/1/p621.pdf" typeof="foaf:Document"> <span property="dc:description">…</span> Author: <span rel="foaf:maker" resource="http://sebastian.tramp.name">…</span> </p>
  9. 9. RDFa Example with Named Graphs <div update:from="http://showcase.ontowiki.net/"> <p about="http://sebastian.tramp.name" typeof="foaf:Person"> <img rel="foaf:depiction" src="http://aksw.org/img/…" /> <strong property="foaf:name">Sebastian Tramp</strong> </p> </div> <div update:from="http://publications.aksw.org"> <p about="http://www2009.eprints.org/63/1/p621.pdf" typeof="foaf:Document"> <span property="dc:description">…</span> Author: <span rel="foaf:maker" resource="http://sebastian.tramp.name">…</span> </p> </div> http://buzzword.org.uk/2009/rdfa4/spec
  10. 10. Provenance <link about="http://showcase.ontowiki.net/" rel="update:updateEndpoint" href="http://trunk.ontowiki.net/sparql/" /> <link about="http://showcase.ontowiki.net/" rel="update:updateEndpoint" href="http://trunk.ontowiki.net/sparql/" /> @prefix update: <http://ns.aksw.org/update/> .
  11. 11. Implementation • Page creation Extracted Triples • Client-side page processing XHTML + RDFa • Widget selection/form HTML Form creation RDF Store • Update propagation
  12. 12. System Architecture RDFauthor3 W3C RDFa rdfQuery1 parser2 (+NG) 1http://code.google.com/p/rdfquery/ 2http://www.w3.org/2006/07/SWD/RDFa/impl/js/ 3http://code.google.com/p/rdfauthor/
  13. 13. Widgets • Semantics-aware • Hide confusing options by default • One widget edits one statement's object • Register for widget hooks
  14. 14. Widget Hooks Hook name Hook value (example) subject URI http://id.feedface.de/me rdfs:range of predicate rdfs:Literal rdfs:Datatype of object xsd:string predicate URI http://xmlns.com/foaf/0.1/name rdf:type of object rdfs:Literal
  15. 15. Widgets (contd.) xsd:date rdf:Resource
  16. 16. Overlay Form • Structure-agnostic • Widgets can be grouped by predicate • Decelerated workflow
  17. 17. Inline Form • Seamless integration • Form layout follows markup structure • Structure-aware • Problems with certain RDFa features
  18. 18. Update Propagation • Widgets update graphs • Calculate diff graphs RDF Store • Sent via SPARQL/Update to each source
  19. 19. Use Cases and Evaluation
  20. 20. OntoWiki
  21. 21. Wiki Pages
  22. 22. Wiki Pages (contd.)
  23. 23. Data Collection
  24. 24. Data Collection (contd.)
  25. 25. Conclusions • RDFauthor allows to create editable semantic mashups • Shields the user from RDF model intricacies • Minimal impact on the web page being edited
  26. 26. Demo Session Wednesday, 4 – 6pm, Room 2 … or anytime

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