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Ks2007 Semanticweb In Action
 

Ks2007 Semanticweb In Action

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Ks2007 Semanticweb In Action Ks2007 Semanticweb In Action Presentation Transcript

  • The SemanticWeb in Action Kennissystemen, December 2007 Rinke Hoekstra
  • Overview
    • The Semantic Web
    • Languages and Integration
    • Storage and Querying
    • Browsing and Viewing
    • Mashups
    • ... does it really exist?
  • The Semantic Web Ideology
    • Partial solutions are great too!
    • Layer cake
    OWL
  • Languages: RDF notations
    • Different ways of writing RDF
      • RDF/XML
      • RDF/XML Abbrev
      • N3
        • Turtle only allows valid RDF-graphs
        • Ntriple one triple per line, fully qualified id’s.
  • Languages: RDF(S)/XML Code Example.
    • <rdf:RDF
    • xmlns:rdf=“http://www.w3.org/1999/02/22-rdf-syntax-ns#”
    • xmlns:rdfs=&quot;http://www.w3.org/TR/rdf-schema/&quot;
    • xmlns:uva=“http://www.uva.nl/rdf#”
    • xmlns=“http://www.uva.nl/people”>
    • <rdf:Description rdf:ID=“#radboud”>
    • <rdf:type rdf:resource=“http://www.uva.nl/rdf#AssociateProfessor”/>
    • <uva:name>Radboud Winkels</uva:name>
    • <uva:teaches rdf:resource=“http://www.uva.nl/courses#ks2007”/>
    • </rdf:Description>
    • <uva:Course rdf:about=“http://www.uva.nl/courses#ks2007”/>
    • <rdfs:Class rdf:about=“http://www.uva.nl/rdf#AssociateProfessor”>
    • <rdfs:subClassOf rdf:resource=“http://www.uva.nl/rdf#StaffMember”/>
    • </rdfs:Class>
    • <rdf:Property rdf:about=“http://www.uva.nl/rdf#teaches”>
    • <rdfs:domain rdf:resource=“http://www.uva.nl/rdf#Professor”/>
    • <rdfs:range rdf:resource=“http://www.uva.nl/rdf#Course”/>
    • </rdf:Property>
    • </rdf:RDF>
  • Languages: N3
    • @prefix rdf:<http://www.w3.org/1999/02/22-rdf-syntax-ns#>.
    • @prefix rdfs:<http://www.w3.org/TR/rdf-schema/>.
    • @prefix uva:<http://www.uva.nl/rdf#>.
    • @prefix courses:<http://www.uva.nl/courses#>.
    • @prefix :<http://www.uva.nl/people#>.
    • uva:AssociateProfessor a rdfs:Class;
    • rdfs:subClassOf uva:StaffMember.
    • uva:teaches a rdf:Property;
    • rdfs:domain uva:AssociateProfessor;
    • rdfs:range uva:Course.
    • :radboud a uva:AssociateProfessor;
    • uva:name ”Radboud Winkels”^^xsd:string;
    • uva:teaches courses:ks2007.
    • courses:ks2007 a uva:Course.
  • Languages: Important Message
    • Multiple Syntaxes!
    • RDF statements are:
      • Triples <subject, predicate,object>
      • Distributed
      • Always about something else
      • ... but can be about other RDF triples as well.
    • Metadata
  • Integration
    • How to add this ‘meta’ to my ‘data’?
    • Three options:
      • Oldfashioned HTML: <link rel='meta' type='application/rdf+xml' href='http://www.leibnizcenter.org/~hoekstra/foaf.rdf' title='FOAF'>
      • HTTP 303 `see other’ http://www.w3.org/TR/swbp-vocab-pub/
      • Inline
  • Integration: 303 See Other
  • Integration: Inline
    • RDFa
      • Attributes on XHTML elements
      • http://www.w3.org/TR/xhtml-rdfa-primer
    • GRDDL
      • Gleaning Resource Descriptions from Dialects of Languages
      • Explicit reference to XSL transformation
      • http://www.w3.org/TR/grddl/
  • Integration: RDFa Example
    • In XHTML:
    • <?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?>
    • <!DOCTYPE html PUBLIC &quot;-//W3C//DTD XHTML+RDFa 1.0//EN&quot;
    • &quot;http://www.w3.org/MarkUp/DTD/xhtml-rdfa-1.dtd&quot;>
    • <html xmlns:cal=&quot;http://www.w3.org/2002/12/cal/ical#&quot;>
    • <head><title>Jo's Friends and Family Blog</title></head>
    • <body>
    • <p instanceof=&quot;cal:Vevent&quot;>
    • I'm holding
    • <span property=&quot;cal:summary&quot;>one last summer Barbecue</span>,
    • on
    • <span property=&quot;cal:dtstart&quot; content=&quot;20070916T1600-0500&quot;>
    • September 16th at 4pm.
    • </span>
    • </p>
    • </body>
    • </html>
    • In RDF:
    • _:blanknode0
    • rdf:type cal:Vevent;
    • cal:summary &quot;last summer Barbecue&quot;;
    • cal:dtstart &quot;20070916T1600-0500&quot; .
  • Storage (on the web)
    • As documents
      • .rdf, .n3, .turtle, .html
    • In a RDF triple-store
      • Sesame ( http://www.openrdf.org )
      • Jena/Joseki ( http://jena.sourceforge.net )
    • RDF(S)/OWL reasoning
      • Jena’s OntModel
      • Sesame OWLIM Sail module
    • SPARQL Endpoints
      • Results as JSON (JavaScript Object Notation)
    • http://draco.leibnizcenter.org:8180/openrdf-sesame
  • Querying
    • Many languages
      • SPARQL, nRQL, SeRQL, etc.
    • SPARQL:
      • http://www.w3.org/TR/rdf-sparql-query/
    • Example
    • PREFIX course: <http://www.uva.nl/courses#>
    • PREFIX uva: <http://www.uva.nl/rdf#>
    • SELECT ?name
    • WHERE
    • { ?x uva:teaches course:ks2007.
    • ?x uva:name ?name }
    • ?x binds with <http://www.uva.nl/people#radboud>
    • ?name binds with “Radboud Winkels”^^xsd:string
  • Interlude: Demos
    • Demos
      • HTTP 303 See other
      • Sesame Repository
      • Querying Bibliography in TopBraid
  • Browsing and Viewing
    • How to unlock your RDF/OWL to users?
      • Custom applications (PizzaFinder)
      • Generic RDF Browsers (Faceted Browsing)
    • How to present your RDF/OWL to users?
      • Custom applications (TopBraid Geo)
      • Generic RDF Visualisation (Fresnel Lenses)
  • Browsing: Facets
    • Multi-dimensional search
    • User filters available information
    • Context dependent
    • Facet
      • UI element
      • Values of a property
      • Number of results
    • Query building
  • Browsing
    • MIT Longwell
      • http://simile.mit.edu/longwell/demo/libraries
    • /facet
      • http://slashfacet.semanticweb.org
    • Flamenco
    • RDFBrowser
    • Exhibit/Potluck
      • http://simile.mit.edu/potluck
    • LENA
    • OpenAcademia
      • http://vu.openacademia.org
  • Viewing
    • Tables are boring!
    • Different data? Different presentation:
      • URI/URL
      • Images
      • Strings
      • Coordinates
    • Filtering data
    • Aggregating data
  • Viewing: Fresnel
    • RDF specification of
      • What data to present, and
      • How to present it
    • http://www.w3.org/2005/04/fresnel-info
    • Lenses
      • Group information (class membership, SPARQL result)
    • Formats
      • Specify how property values should be rendered
  • Viewing: Fresnel lens
    • :foafPersonDefaultLens rdf:type fresnel:Lens ;
    • fresnel:purpose fresnel:defaultLens ;
    • fresnel:classLensDomain foaf:Person ;
    • fresnel:group :foafGroup ;
    • fresnel:showProperties ( foaf:name
    • foaf:surname
    • foaf:depiction ) .
    • :knowsLens rdf:type fresnel:Lens ;
    • fresnel:classLensDomain foaf:Person ;
    • fresnel:group :foafGroup ;
    • fresnel:showProperties ( foaf:name
    • foaf:surname
    • foaf:mbox
    • [ rdf:type fresnel:PropertyDescription ;
    • fresnel:property foaf:knows ;
    • fresnel:sublens :foafPersonDefaultLens ] ) .
  • Viewing: Fresnel format
    • :foafGroup rdf:type fresnel:Group ;
    • fresnel:stylesheetLink <http://www.example.org/example.css> .
    • :depictFormat rdf:type fresnel:Format ;
    • fresnel:propertyFormatDomain foaf:depiction ;
    • fresnel:label fresnel:none ;
    • fresnel:value fresnel:image ;
    • fresnel:valueStyle &quot;imageWithThickBorder&quot;^^fresnel:styleClass ;
    • fresnel:group :foafGroup .
    • :urlFormat rdf:type fresnel:Format ;
    • fresnel:propertyFormatDomain foaf:homepage ;
    • fresnel:propertyFormatDomain foaf:mbox ;
    • fresnel:value fresnel:externalLink ;
    • fresnel:labelStyle &quot;basicLabel&quot;^^fresnel:styleClass ;
    • fresnel:valueStyle &quot;basicUrl&quot;^^fresnel:styleClass ;
    • fresnel:group :foafGroup .
  • Interlude: Demo
    • Custom:
      • Pizza Finder
      • OpenAcademia
    • Generic:
      • Longwell
      • /Facet (e-Culture)
  • Interlude: Demo Mashups
    • Yahoo Pipes
      • http://pipes.yahoo.com
    • Potluck
    • GeoTagging
  • Million dollar question
    • ... does the SemanticWeb really exist?
    • Semantics: yes
    • Web: mwoah
      • Friend-of-a-Friend (FOAF)
      • RSS feeds (pingbacks etc.)
      • Web 2.0: Tagging + Mashups
    • However
      • The nuts ‘n bolts are ready,
      • And we’ve got the data!
  • Resources
    • http://www.w3.org RDF(S), N3, OWL, SPARQL, RDFa, GRDDL, XML, XMLSchema, XSLT, CSS, XPath, fresnel...
    • http://www.semanticweb.org /facet, other resources
    • http://www.planetrdf.com Aggregated RSS feed of the cool & famous
  • Yahoo Pipes Editing
  • Yahoo Pipes Result
  • /facet
  • Longwell