Callimachus intro 20100928

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A brief introduction to the Callimachus Project, an Open Source software project to make the creation of Semantic Web applications easy for Web authors.

Transcript of Callimachus intro 20100928

  • 1. Wednesday, September 29, 2010 1

2. of Cyrenec. 305c. 240 BCE Father of Bibliography (The Pinakes) at the great Library at Alexandria Could not categorize his own work in Aristotles hierarchical systemMega biblion, mega kakon Wednesday, September 29, 2010 2Many writings equals many worries Pinakes: Tables of those who were eminent in every branch of learning, and what they wrote, in 120 volumes Callimachus Quandary was that he could not categorize his own works in Aristotles hierarchy. 3. Wednesday, September 29, 2010 3Semantic Web applications have been hampered by our pre-conceived notions of software architecture. It has taken us ten years to build a full architecture. 4. Wednesday, September 29, 2010 4Like Aristotles hierarchy, we have thumb rules and presumptions in our software architectures. The 3-tier architecture is very useful, but most people equate the data layer with hierarchical or pseudo-hierarchical data stores like relational databases and le systems. 5. 1.Object-RDF mapping 2. RDF Wednesday, September 29, 2010 5We try to address Callimachus Quandary by removing limitations implicit in the n-tier architecture. Objects are exposed to the user interface so we can keep using existing means of creating UIs, but those limitations are not serialized. 6. The painter... does not t the paints to the world. He ts himself to the paint.-- Paul Klee Wednesday, September 29, 20106 7. Wednesday, September 29, 2010 7Older attempts at creating RDF editors suffered from being too close to triples. Other products make an orthogonal mistake by storing objects based on RDF, thus limiting arbitrary relationships in the data. Callimachus tries to avoid both problems by presenting objects to the user while storing RDF natively. 8. Wednesday, September 29, 2010 8In our opinion, Semantic Web apps should look like arbitrary Web pages. 9. RDF Store Web serverHTTP GETClassResource request Viewable RDF response SPARQL queryXMLtemplate apply.xslHTTPresponseHTMLWednesday, September 29, 2010 9 10. Demo Time!Wednesday, September 29, 201010 11. Graph Pattern Queries Every triple is also a triple pattern Any graph can be used within a SPARQL ASK query Basic triple patterns are triples with variables Variables can be stored in triples as URI within a particular namespace Many CONSTRUCT and SELECT queries can be represented using triples with variables Wednesday, September 29, 201011 12. RDFa Pattern Queries RDFa is parsed into RDF Variables are identied by URI namespace for conversion into basic triple patterns Nested tags use OPTIONAL joins to maximise matches RDFa le is used to construct RDFa result of matching triples Callimachus project contains an implementation of the above Wednesday, September 29, 2010 12 13. UI Templates Use external BASE to enable query reuse against different subjects Template for every resource type and activity Activities include: View resource Review resource Edit resource Copy resource Wednesday, September 29, 2010 13 14. RDFa Changesets JavaScript RDFa library for parsing and identifying differences on client side JavaScript library for RDFa aware DOM manipulation POST changes back to server as RDF or SPARQL Update Wednesday, September 29, 2010 14 15. When to use SPARQL RDFa does not include Join types (inner, left, cross, union) FILTER ORDER BY LIMIT, OFFSET GRAPH support For these constructs use SPARQL results with XSLT Wednesday, September 29, 2010 15 16. Managing Resources with RDFa Identify or create a resource vocabulary Create resource templates for every resource typeand activity in RDFa Create search interface with SPARQL and XSLT Semantic Web applications made easy! Wednesday, September 29, 201016 17. For More Information Contact James Leigh David Wood Get involved at, September 29, 201017