1. Flink: Lessons of interoperability Peter Mika Dept. of Business Informatics Free University Amsterdam http://www.cs.vu.nl/~pmika/ 1 st Intl. Workshop on Interoperability of SW portals

2. Content Flink Interoperability Flink + Interoperability

3. What is Flink? Flink is a directory of Semantic Web research Browse the social network of all authors at ISWC ‘01-’04 Profiles with personal information, emails, publications View statistics Download profiles in FOAF format Export for Social Network Analysis Demonstration of latest SW technology 1 st prize at the Semantic Web Challenge (2004) Open source (soon) Try it! http://flink.semanticweb.org

5. Technology highlights Social network mining from the Web and other legacy sources (emails, publications) Social networks based ontology extraction Collection of FOAF data from the SW (“scuttering”) Aggregation and identity reasoning (“smushing”) Custom inferencing using Sesame OWL use sameAs, inverse functional properties Web Service integration geographic lookup WML interface …

6. JUNG Network API Semantic Web Web Sesame FOAF profiles Web mining Emails IMAP or POP3 Sesame Publications Google Scholar, Bibster Network analysis Web application RDF storage Sesame Metadata enrichment (Identity reasoning, geographic lookup)

7. Interoperability (1) Interoperability on the knowledge level = syntax + semantics + context Syntax Easy (but a ‘forgiving’ parser would be nice) Semantics Doable: shared ontologies, ontology mapping (e.g. for foaf:interests), unique object identification (e.g. for foaf:Person), Context Challenge

8. Interoperability (2): Context Provenance: where the information comes from, when was it collected? Time-to-live: how long is it going to stay valid? Trust and ratings: is it considered trustworthy (by someone), is it important (for someone)? Security: who can access it and how? …

9. Interoperability (3): Process How do we find each other? Registries vs. pointers How do we exchange? Connectivity Protocol (e.g. subscriptions vs. advertizements) What do we exchange? Files, access etc. Why would we exchange? The economics

10. Flink and the FOAF-web Flink interoperates with the FOAF-web Producer and consumer of FOAF data But: 762 other definitions of Person (www.swoogle.org), including swrc:Personwww.swoogle.org FOAF-web is the kind of nightmare the SW promises to be Open, decentralized system Distributed data and services Issues of syntax and semantics Lack of authority, privacy etc.

11. Flink and the FOAF-web (2) Majority of files are incorrect XML, RDF or FOAF Errors from the obvious to the sneaky e.g. Ignore FOAF extensions What to do with them? Ignore on import, don’t export FOAF interests? A ‘loose end’ in FOAF (like dc:Creator) Ignore (on import) Who is right? Let the user decide

12. How to contact Dan Brickley?

13. Summary Interoperability is a challenge: Knowledge: syntax + semantics + context Process Interoperability is about coming to an agreement Realize the trade-off between level of commitment vs. scale