1. Semantic Web Publishing Using Named Graphs Named Graphs meet SPARQL Chris Bizer, Freie Universität Berlin, Germany Jeremy Carroll, Hewlett-Packard Labs, UK Pat Hayes, IHMC, USA Patrick Stickler, Nokia, Finland W3C Technical Plenary Boston, 28 February 2005

2. Semantic Web Publishing Using Named Graphs SPARQL Version 20050217 SELECT ?company ?rating WITH local:trustedInformation local:crawlerMonday local:crawlerTuesday FROM website1:graph1 website1:graph2 website2:graph1 website2:graph2 WHERE ( ?g dc:publisher ?name ) ( ?name tpl:trustedBy local:Me ) GRAPH ?g { ( ?company fin:rating ?rating ) ( ?company fin:sector fin:banking ) }

3. Semantic Web Publishing Using Named Graphs RDF Dataset versus Named Graphs RDF Dataset Named Graphs Background Graph

4. Semantic Web Publishing Using Named Graphs Agenda 1.Implementing Named Graphs NG4J – Named Graphs API for Jena Jena - Multimodel TriX and TriG Syntax 2.Signing Named Graphs Semantic Web Publishing Vocabulary (SWP) 3.Use Cases Versioning and Provenance

5. Semantic Web Publishing Using Named Graphs NG4J – Named Graphs API for Jena Extension to the Jena semantic web toolkit APIs for manipulating sets of Named Graphs Memory and database backed storage TriQL query language Serialization using TriX, TriG and collections of RDF/XML files SWP API for signing graphs Available under BSD license

6. Semantic Web Publishing Using Named Graphs NG4Js APIs Named Graph API NamedGraph graph = graphset.createGraph(graphname); graph.add(triple); Quad API graphset.addQuad(quad); Provenance enabled Jena Model API Model model = graphset.asJenaModel("http://example.org/defaultgraph"); iterator = jenaStatement.listGraphNames(); provides migration path for existing applications

7. Semantic Web Publishing Using Named Graphs TriX Straight forward XML serialization of the abstract syntax allows the usage of generic XML tools like XSLT or XQuery http://www.bizer.de/InformationAboutRichard http://richard.cyganiak.de/foaf.rdf#RichardCyganiak http://xmlns.com/foaf/0.1/mbox mailto:richard@cyganiak.de http://www.bizer.de/ProvenanceInformation http://www.bizer.de/InformationAboutRichard http://purl.org/dc/elements/1.1/author Chris Bizer

8. Semantic Web Publishing Using Named Graphs TriG based on Turtle, extended with graph naming @prefix dc:. @prefix ex:. @prefix :. :G1 { _:Monica ex:name "Monica Murphy". _:Monica ex:email. :G1 ex:disallowedUsage ex:Marketing } :G2 { :G1 ex:author :Chris. :G1 ex:date "2003-09-03"^^xsd:date }

9. Semantic Web Publishing Using Named Graphs TriX, TriG and SPARQL Protocol getGraph() GET /qps?graph=2.rdf&graph=4.rdf HTTP/1.1 Accept: text/n3 GetGraph returns the serialized RDFGraph identified by OperationTarget or all of the separately serialized RDFGraphs identifed by OperationTargetSet Protocol Spec Accept: text/trig Avoids redundant transmission of namespace declarations Accept: application/trix Allows the transformation of query results using XSLT

10. Semantic Web Publishing Using Named Graphs SPARQL Protocol getGraph() and Wildcards Our experience: Repositories quickly fill with hundreds of graphs. The query environment may provide the RDF dataset to be queried. SPARQL Query Language Spec Wildcards might also be useful in SPARQL Protocol. GET /qps?graph=* HTTP/1.1

11. Semantic Web Publishing Using Named Graphs Publishing with Signatures swp:SignatureMethod specifies a graph canonicalization method a signature method provided by XML Signature Semantic Web Publishing Vocabulary (SWP-2)

12. Semantic Web Publishing Using Named Graphs Publishing with Signatures - Example :G1 { :Monica ex:name "Monica Murphy. :Chris ex:name "Chris Bizer". :G1 swp:assertedBy :G1. :G1 swp:authority _:s. :G1 swp:signatureMethod swp:JjcRdfC14N-rsa-sha1. :G1 swp:signature "..."ˆˆxsd:base64Binary. _:s foaf:mbox. _:s swp:certificate "..."ˆˆxsd:base64Binary }

13. Semantic Web Publishing Using Named Graphs Publishing with Signatures - Example :G1 {:Jeremy ex:name "Jeremy Carrol" } :G2 {:Chris ex:name "Chris Bizer" } :G3 {:G1 swp:assertedBy :G3. :G1 swp:digestMethod swp:JjcRdfC14N-sha1. :G1 swp:digest "..."ˆˆxsd:base64Binary. :G2 swp:assertedBy :G3. :G2 swp:digestMethod swp:JjcRdfC14N-sha1. :G2 swp:digest "..."ˆˆxsd:base64Binary. :G3 swp:assertedBy :G3. :G3 swp:signatureMethod swp:JjcRdfC14N-rsa-sha1. :G3 swp:signature "..."ˆˆxsd:base64Binary. :G3 swp:authority _:s. _:s foaf:mbox _:s swp:certificate "..."ˆˆxsd:base64Binary }

14. Semantic Web Publishing Using Named Graphs NG4J Use Cases Gnowsis Semantic Desktop Leo Sauermann, DFKI, Germany Provenance tracking in a data integration framework Source Code Versioning Rowland Watkins, University of Southampton, UK Relation and provenance tracking of source code changes SWED Semantic Web Environmental Directory SWAD-Europe, HP Labs and ILRT Provenance tracking in a data integration framework Ontology Evolution in Live Science Chris Catton, University of Oxford, UK Tracking of concept evolution and paradigm shifts TriQL.P Trust Architecture Chris Bizer, Freie Universität Berlin, Germany Filtering information using different trust policies

15. Semantic Web Publishing Using Named Graphs So, whats the holy grail? Reification ? Quads ? Named Graphs ? RDF Dataset ?

16. Semantic Web Publishing Using Named Graphs Thanks :-) Named Graph Website Links to TriX, TriG, TriQL, RDFQ Specs http://www.w3.org/2004/03/trix/ Named Graphs, Provenance and Trust Carroll, Bizer, Hayes and Stickler http://www.hpl.hp.com/techreports/2004/HPL-2004-57.html NG4J - Named Graphs API for Jena http://www.wiwiss.fu-berlin.de/suhl/bizer/ng4j/