Transcript The making of Flink

Flink:
Lessons of
interoperability
Peter Mika
Dept. of Business Informatics
Free University Amsterdam
http://www.cs.vu.nl/~pmika/
1st Intl. Workshop on
Interoperability of SW portals
Content
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Flink
Interoperability
Flink + Interoperability
What is Flink?
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Flink is a directory of Semantic Web research
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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
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1st prize at the Semantic Web Challenge (2004)
Open source (soon)
Try it!
http://flink.semanticweb.org
Technology highlights
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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
…
Semantic Web
Web
Web
mining
Sesame
Emails
FOAF
profiles
IMAP
or
POP3
Google
Scholar,
Bibster
Sesame
Sesame
Publications
Sesame
Sesame
RDF
storage
Network API
Network
analysis
Metadata enrichment
(Identity reasoning,
geographic lookup)
JUNG
Web application
Interoperability (1)
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Interoperability on the knowledge level =
syntax + semantics + context
Syntax
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Semantics
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Easy (but a ‘forgiving’ parser would be nice)
Doable: shared ontologies, ontology mapping (e.g. for
foaf:interests), unique object identification (e.g. for
foaf:Person),
Context
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Challenge
Interoperability (2): Context
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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?
…
Interoperability (3):
Process
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How do we find each other?
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How do we exchange?
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Connectivity
Protocol (e.g. subscriptions vs. advertizements)
What do we exchange?
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Registries vs. pointers
Files, access etc.
Why would we exchange?
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The economics
Flink and the FOAF-web
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Flink interoperates with the FOAF-web
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Producer and consumer of FOAF data
But: 762 other definitions of Person
(www.swoogle.org), including swrc:Person
FOAF-web is the kind of nightmare the SW
promises to be
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Open, decentralized system
Distributed data and services
Issues of syntax and semantics
Lack of authority, privacy etc.
Flink and the FOAF-web (2)
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Majority of files are incorrect XML, RDF or FOAF
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FOAF extensions
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What to do with them?
Ignore on import, don’t export
FOAF interests?
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Errors from the obvious to the sneaky
e.g. <foaf:mbox_sha1sum />
Ignore
A ‘loose end’ in FOAF (like dc:Creator)
Ignore (on import)
Who is right?
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Let the user decide
How to contact
Dan Brickley?
Summary
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Interoperability is a challenge:
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Knowledge: syntax + semantics + context
Process
Interoperability is about coming to an
agreement
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Realize the trade-off between level of commitment
vs. scale