W 3 C Technical Plenary Boston 28 February

W 3 C Technical Plenary Boston, 28 February 2005 Named Graphs meet SPARQL Chris Bizer, Freie Universität Berlin, Germany Jeremy Carroll, Hewlett-Packard Labs, UK Pat Hayes, IHMC, USA Patrick Stickler, Nokia, Finland Semantic Web Publishing Using Named Graphs

SPARQL Version 20050217 SELECT ? company ? rating WITH local: trusted. Information local: crawler. Monday local: crawler. Tuesday FROM website 1: graph 1 website 1: graph 2 website 2: graph 1 website 2: graph 2 WHERE ( ? g dc: publisher ? name ) ( ? name tpl: trusted. By local: Me ) GRAPH ? g { ( ? company fin: rating ? rating ) ( ? company fin: sector fin: banking ) } Semantic Web Publishing Using Named Graphs

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

Agenda 1. Implementing Named Graphs n NG 4 J – Named Graphs API for Jena n Jena - Multimodel n Tri. X and Tri. G Syntax 2. Signing Named Graphs < Semantic Web Publishing Vocabulary (SWP) 3. Use Cases n Versioning and Provenance Semantic Web Publishing Using Named Graphs

NG 4 J – Named Graphs API for Jena <Extension to the Jena semantic web toolkit <APIs for manipulating sets of Named Graphs <Memory and database backed storage <Tri. QL query language <Serialization using Tri. X, Tri. G and collections of RDF/XML files <SWP API for signing graphs <Available under BSD license Semantic Web Publishing Using Named Graphs

NG 4 J’s APIs <Named Graph API n Named. Graph graph = graphset. create. Graph(graphname); n graph. add(triple); <Quad API n graphset. add. Quad(quad); <Provenance enabled Jena Model API n Model model = graphset. as. Jena. Model("http: //example. org/defaultgraph"); n iterator = jena. Statement. list. Graph. Names(); n provides migration path for existing applications Semantic Web Publishing Using Named Graphs

Tri. X < Straight forward XML serialization of the abstract syntax <Tri. X xmlns="http: //www. w 3. org/2004/03/trix-1/"> <graph> <uri>http: //www. bizer. de/Information. About. Richard</uri> <triple> <uri>http: //richard. cyganiak. de/foaf. rdf#Richard. Cyganiak</uri> <uri>http: //xmlns. com/foaf/0. 1/mbox</uri> <uri>mailto: richard@cyganiak. de</uri> </triple> </graph> <uri>http: //www. bizer. de/Provenance. Information</uri> <triple> <uri>http: //www. bizer. de/Information. About. Richard</uri> <uri>http: //purl. org/dc/elements/1. 1/author</uri> <plain. Literal>Chris Bizer</plain. Literal> </triple> </graph></Tri. X> < allows the usage of generic XML tools like XSLT or XQuery Semantic Web Publishing Using Named Graphs

Tri. G < based on Turtle, extended with graph naming @prefix dc: <http: //purl. org/dc/elements/1. 1/>. @prefix ex: <http: //www. example. org/vocabulary/>. @prefix : <http: //www. example. org/example. Document/>. : G 1 { _: Monica ex: name "Monica Murphy". _: Monica ex: email <mailto: monica@murphy. org>. : G 1 ex: disallowed. Usage ex: Marketing } : G 2 { : G 1 ex: author : Chris. : G 1 ex: date "2003 -09 -03"^^xsd: date } Semantic Web Publishing Using Named Graphs

Tri. X, Tri. G and SPARQL Protocol get. Graph() <GET /qps? graph=2. rdf&graph=4. rdf HTTP/1. 1 Accept: text/n 3 <“Get. Graph returns the serialized RDFGraph identified by Operation. Target or all of the separately serialized RDFGraphs identifed by Operation. Target. Set” Protocol Spec <Accept: text/trig n Avoids redundant transmission of namespace declarations <Accept: application/trix n Allows the transformation of query results using XSLT Semantic Web Publishing Using Named Graphs

SPARQL Protocol get. Graph() 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. n GET /qps? graph=* HTTP/1. 1 Semantic Web Publishing Using Named Graphs

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

Publishing with Signatures - Example : G 1 { : Monica ex: name "Monica Murphy“. : Chris ex: name "Chris Bizer". : G 1 swp: asserted. By : G 1 swp: authority _: s. : G 1 swp: signature. Method swp: Jjc. Rdf. C 14 N-rsa-sha 1. : G 1 swp: signature ". . . "ˆˆxsd: base 64 Binary. _: s foaf: mbox <mailto: patrick. stickler@nokia. com>. _: s swp: certificate ". . . "ˆˆxsd: base 64 Binary } Semantic Web Publishing Using Named Graphs

Publishing with Signatures - Example : G 1 {: Jeremy ex: name "Jeremy Carrol" } : G 2 {: Chris ex: name "Chris Bizer" } : G 3 {: G 1 swp: asserted. By : G 3. : G 1 swp: digest. Method swp: Jjc. Rdf. C 14 N-sha 1. : G 1 swp: digest ". . . "ˆˆxsd: base 64 Binary. : G 2 swp: asserted. By : G 3. : G 2 swp: digest. Method swp: Jjc. Rdf. C 14 N-sha 1. : G 2 swp: digest ". . . "ˆˆxsd: base 64 Binary. : G 3 swp: asserted. By : G 3. swp: signature. Method swp: Jjc. Rdf. C 14 N-rsa-sha 1. swp: signature ". . . "ˆˆxsd: base 64 Binary. swp: authority _: s foaf: mbox <mailto: patrick. stickler@nokia. com> _: s swp: certificate ". . . "ˆˆxsd: base 64 Binary } Semantic Web Publishing Using Named Graphs

NG 4 J Use Cases < Gnowsis Semantic Desktop n Leo Sauermann, DFKI, Germany n Provenance tracking in a data integration framework < Source Code Versioning n Rowland Watkins, University of Southampton, UK n Relation and provenance tracking of source code changes < SWED Semantic Web Environmental Directory n SWAD-Europe, HP Labs and ILRT n Provenance tracking in a data integration framework < Ontology Evolution in Live Science n Chris Catton, University of Oxford, UK n Tracking of concept evolution and paradigm shifts < Tri. QL. P Trust Architecture n Chris Bizer, Freie Universität Berlin, Germany n Filtering information using different trust policies Semantic Web Publishing Using Named Graphs

So, what’s the holy grail? <Reification ? <Quads ? <Named Graphs ? <RDF Dataset ? Semantic Web Publishing Using Named Graphs

Thanks : -) <Named Graph Website n Links to Tri. X, Tri. G, Tri. QL, RDFQ Specs n http: //www. w 3. org/2004/03/trix/ <Named Graphs, Provenance and Trust n Carroll, Bizer, Hayes and Stickler n http: //www. hpl. hp. com/techreports/2004/HPL-2004 -57. html <NG 4 J - Named Graphs API for Jena n http: //www. wiwiss. fu-berlin. de/suhl/bizer/ng 4 j/ Semantic Web Publishing Using Named Graphs