rdfauthor (ekaw)
Post on 11-May-2015
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Employing RDFa for Collaborative Knowledge Engineering
Sebastian Tramp, Norman Heino, Sören Auer, Philipp Frischmuth
Agile Knowledge Engineering and Semantic Web (AKSW) – Universität Leipzig
• HTML forms are unaware of semantics
• HTML5 allows pre-defined input state semantics
• Sophisticated user support requires definable semantics!
on the Web
Knowledge Engineering
Currently: hard-wired semantics, abuse of class attributes
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/
Knowledge Engineering
• RDFa page, updatable knowledge store
• "Intelligent" editing components (widgets)
• Supporting the user
by Employing RDFa
XHTML+
RDFaWeb
Server+
RDF Store
Edit
SPARQL/Update
HTTP
Requirements
• Editing data chunks
• Standards-based update
• Light-weight addition
• Extensible widget pool
• Multiple sources
for RDFauthor
Named Graphs and Provenance
• Data source for each triple
• Update endpoint (SPARQL/Update)
• Query endpoint for reference (SPARQL)
Extending RDFa
<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>
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>
<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>
RDFa Examplefrom Two Sources
RDFa Example
http://buzzword.org.uk/2009/rdfa4/spec
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>
<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/" />
Provenance
@prefix update: <http://ns.aksw.org/update/> .
Implementation
HTML Form• Widget selection/form creation
RDF Store
• Update propagation
Extracted Triples
• Client-side page processing XHTML
+RDFa
• Page creation
System Architecture
W3C RDFa parser2 (+NG)rdfQuery1
RDFauthor3
1http://code.google.com/p/rdfquery/2http://www.w3.org/2006/07/SWD/RDFa/impl/js/3http://code.google.com/p/rdfauthor/
Widgets
• Semantics-aware
• Hide confusing options by default
• One widget edits one statement's object
• Register for widget hooks
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
Widgets (contd.)
xsd:date
rdf:Resource
Overlay Form
• Structure-agnostic
• Widgets can be grouped by predicate
• Decelerated workflow
Inline Form
• Seamless integration
• Form layout follows markup structure
• Structure-aware
• Problems with certain RDFa features
Update Propagation
• Widgets update graphs
• Calculate diff graphs
• Sent via SPARQL/Update to each source
RDF Store
Use Casesand Evaluation
OntoWiki
Wiki Pages
Wiki Pages (contd.)
Data Collection
Data Collection (contd.)
Conclusions
• RDFauthor allows to create editable semantic mashups
• Shields the user from RDF model intricacies
• Minimal impact on the web page being edited
Demo Session
Wednesday, 4 – 6pm, Room 2
… or anytime
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