Mind the Web!

1. Mind the Web! Valentin Zacharias, Andreas Abecker, Imen Borgi, Simone Braun, Andreas Schmidt FZI Karlsruhe, Germany Denny Vrandečić AIFB, Universität Karlsruhe (TH), Germany Workshop on new forms of reasoning for the Semantic Web: scalable, tolerant and dynamic Busan, Korea November 11, 2007

2. Thesis Not taking the web in Semantic Webserious has lead many Semantic Web researchers to do Semantic Systems and reasoning research without trying to tackle the fundamental challenges of the Semantic Web.

3. Overview • Hypotheses • Current trends and misconceptions • Problems • Some solutions

4. Hypotheses Web scale is not “just a bit larger” Ontologies are always changing There is no right ontology

5. A triple

10. OWLIM 107 Triples [29] Suez Canal

11. RDF Store subsecond querying 108 Triples [25,26] Moon Fensel / Harmelen estimate 1014 Triples

12. ~109 Triples Earth Fensel / Harmelen estimate 1014 Triples

13. ~1010 Triples Jupiter Fensel / Harmelen estimate 1014 Triples

14. ~1011 Triples Fensel / Harmelen estimate 1014 Triples

15. ~1014 Triples Distance Sun – Pluto Fensel / Harmelen estimate 1014 Triples

16. Hypotheses Web scale is not “just a bit larger” Ontologies are always changing There is no right ontology

17. Dynamics of Web 2.0 • 100 edits in Wikipedia • 200 tags in del.icio.us • 270 image uploads to flickr • 1100 blog entries per minute! • No reason to believe the Semantic Web will be any less dynamic – rather more!

18. Reasons for change • Error correction • New information • Change of view • Change of the world None of these reasons will disappear

19. Hypotheses Web scale is not “just a bit larger” Ontologies are always changing There is no right ontology

20. There is no right ontology • Many different views • Conflicting views and interests • Semantic desktop -> many ontologies • Ontologies are abstractions • Different tasks lead to different ontologies • Many design choices • Google Base: 100.000 schemas • Intentionally false (Spam)

21. Misconceptions Classical reasoning approaches will be used on the web Assumption of correctness It is a logical web, not a statistical one

22. Making weaker languages “Reducing the expressive power of a logic does not solve any problems faster; its only effect is to make some problems impossible to state.” John Sowa

23. A logical web • Repeating a statement does not make it more true

26. Web Data Aggregation “Statistical” aggregation necessary for opinions Important in Information Retrieval (see PageRank)

27. A logical web • Repeating a statement does not make it more true • But more likely • Rules in news: three sources for a story • Counting and relations matter • Combine this with reasoning

28. Solutions?

29. See paper for more More approaches to reasoning • KB partitioning and summarizing • Approximate reasoning • Massive parallelization • Special purpose reasoners • Deductive database techniques • Combine retrieval and reasoning • Emergence of Semantics • Ontology Maturing • Change on the Semantic Web

30. Conclusions • Many promising approaches • But which one to choose? • Use cases are needed most! • To evaluate the approaches • To point into the right direction • This is why this workshop is here…

31. Thank you! Not taking the web in Semantic Webserious has lead many Semantic Web researchers to do Semantic Systems and reasoning research without trying to tackle the fundamental challenges of the Semantic Web.