1. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 1 http://www.aifb.uni-karlsruhe.de/WBS 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. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 2 http://www.aifb.uni-karlsruhe.de/WBS Thesis Not taking the web in Semantic Web serious 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. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 3 http://www.aifb.uni-karlsruhe.de/WBS Overview Hypotheses Current trends and misconceptions Problems Some solutions

4. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 4 http://www.aifb.uni-karlsruhe.de/WBS Hypotheses 1. Web scale is not just a bit larger 2. Ontologies are always changing 3. There is no right ontology

5. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 5 http://www.aifb.uni-karlsruhe.de/WBS A triple

6. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 6 http://www.aifb.uni-karlsruhe.de/WBS

7. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 7 http://www.aifb.uni-karlsruhe.de/WBS

8. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 8 http://www.aifb.uni-karlsruhe.de/WBS

9. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 9 http://www.aifb.uni-karlsruhe.de/WBS

10. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 10 http://www.aifb.uni-karlsruhe.de/WBS OWLIM 10 7 Triples [29] Suez Canal

11. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 11 http://www.aifb.uni-karlsruhe.de/WBS RDF Store subsecond querying 10 8 Triples [25,26] Moon Fensel / Harmelen estimate 10 14 Triples

12. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 12 http://www.aifb.uni-karlsruhe.de/WBS ~10 9 Triples Earth Fensel / Harmelen estimate 10 14 Triples

13. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 13 http://www.aifb.uni-karlsruhe.de/WBS Jupiter Fensel / Harmelen estimate 10 14 Triples ~10 10 Triples

14. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 14 http://www.aifb.uni-karlsruhe.de/WBS Fensel / Harmelen estimate 10 14 Triples ~10 11 Triples

15. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 15 http://www.aifb.uni-karlsruhe.de/WBS Distance Sun – Pluto Fensel / Harmelen estimate 10 14 Triples ~10 14 Triples

16. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 16 http://www.aifb.uni-karlsruhe.de/WBS Hypotheses 1. Web scale is not just a bit larger 2. Ontologies are always changing 3. There is no right ontology

17. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 17 http://www.aifb.uni-karlsruhe.de/WBS 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. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 18 http://www.aifb.uni-karlsruhe.de/WBS Reasons for change Error correction New information Change of view Change of the world None of these reasons will disappear

19. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 19 http://www.aifb.uni-karlsruhe.de/WBS Hypotheses 1. Web scale is not just a bit larger 2. Ontologies are always changing 3. There is no right ontology

20. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 20 http://www.aifb.uni-karlsruhe.de/WBS 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. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 21 http://www.aifb.uni-karlsruhe.de/WBS Misconceptions 1. Classical reasoning approaches will be used on the web 2. Assumption of correctness 3. It is a logical web, not a statistical one

22. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 22 http://www.aifb.uni-karlsruhe.de/WBS 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. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 23 http://www.aifb.uni-karlsruhe.de/WBS Classical Reasoning Approaches Even Polynomial is much to slow, unless a subset of statements is retrieved first Identifying this subset can be non trivial and is at the core of the challenge posed by the Semantic Web

24. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 24 http://www.aifb.uni-karlsruhe.de/WBS Classical Reasoning Approaches – Focus theoretical worst cases Undecidability – may be harmless in all cases that matter, completeness unachievable in practice anyway Worst Case complexity – may be a bad guidance for usefulness. Harmelen 2006

25. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 25 http://www.aifb.uni-karlsruhe.de/WBS Assumption of correctness Reasoning is always on perfect statements Dealing with imperfection is preprocessing Vagueness Uncertainty Intentionally false Errors Outdated

26. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 26 http://www.aifb.uni-karlsruhe.de/WBS A logical web Repeating a statement does not make it more true

27. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 27 http://www.aifb.uni-karlsruhe.de/WBS

28. Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 28 http://www.aifb.uni-karlsruhe.de/WBS

29. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 29 http://www.aifb.uni-karlsruhe.de/WBS Web Data Aggregation Statistical aggregation necessary for opinions Important in Information Retrieval (see PageRank)

30. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 30 http://www.aifb.uni-karlsruhe.de/WBS 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

31. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 31 http://www.aifb.uni-karlsruhe.de/WBS Solutions?

32. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 32 http://www.aifb.uni-karlsruhe.de/WBS 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

33. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 33 http://www.aifb.uni-karlsruhe.de/WBS 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…

34. AIFB Denny Vrandečić – AIFB, Universität Karlsruhe (TH) 34 http://www.aifb.uni-karlsruhe.de/WBS Thank you! Not taking the web in Semantic Web serious has lead many Semantic Web researchers to do Semantic Systems and reasoning research without trying to tackle the fundamental challenges of the Semantic Web.