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Semantic Web questions we couldn't ask 10 years ago

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Talk given at the SSSW 2013 Semantic Web Summerschool.
Part 1: What is "Semantic Web" (in 4 principles and 1 movie)
Part 2: What question can we ask now that we couldn't ask 10 years ago
Part 3: Treat Computer Science as a *science*, not just as engineering!
(this part a short version of http://slidesha.re/SaUhS4 )

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Semantic Web questions we couldn't ask 10 years ago

  1. 1. Frank van Harmelen All the questions we couldn’t ask 10 years ago Creative Commons License: allowed to share & remix, but must attribute & non-commercial
  2. 2. The bad news: you’re going to get 3 talks 1. Where are we now? – The Semantic Web in 4 principles & a movie – Did we get anywhere? 2. Now what? – Questions we couldn’t ask 10 years ago 3. Methodological hobby horse – Science or engineering?
  3. 3. Semantic Web: What is it?
  4. 4. “The Semantic Web” a.k.a. “The Web of Data”
  5. 5. http://www.youtube.com/watch?v=tBSdYi4EY3s
  6. 6. P1. Give all things a name
  7. 7. P2. Relations form a graph between things
  8. 8. P3. The names are addresses on the Web x T [<x> IsOfType <T>] different owners & locations <analgesic>
  9. 9. P1+P2+P3 = Giant Global Graph
  10. 10. P4. explicit & formal semantics • assign types to things • assign types to relations • organise types in a hierarchy • impose constraints on possible interpretations
  11. 11. Examples of “semantics” married-to • is male • married-to relates males to females • married-to relates 1 male to 1 female • = lowerbound upperbound
  12. 12. Semantic Web: Where are we now?
  13. 13. Did we get anywhere? • Google = meaningful search • NXP = data integration • BBC = content re-use • Wallmart= SEO (RDF-a) • data.gov = data-publishing
  14. 14. NXP: data integration about 26.000 products Triple store Triple store Departments Customers Notice the 3-layer architecture
  15. 15. BBC Notice the 3-layer architecture
  16. 16. Did we get anywhere? • Google = meaningful search • NXP = data integration • BBC = content re-use • BestBuy = SEO (RDF-a) • data.gov = data-publishing Oracle DB, IBM DB2 Reuters, New York Times, Guardian Sears, Kmart, OverStock, Volkswagen, Renault GoodRelations ontology, schema.org
  17. 17. Size Matters: 25-45 billion facts
  18. 18. The questions that we couldn’t ask 10 years ago
  19. 19. • Heterogeneity • Self-organisation, long tails • Distribution • Provenance & trust • Dynamics • Errors & Noise • Scale
  20. 20. heterogeneity is unavoidable •Linguistic, •Structural, •Logical, •Statistical, .... Socio- economic first to market market- share
  21. 21. Self-organisation
  22. 22. Self-organisation
  23. 23. Self-organisation
  24. 24. Self-organisation
  25. 25. Self-organisation
  26. 26. Bio-medical ontologies in Bio-portal > 5 links Self-organisation
  27. 27. knowledge follows a long-tail
  28. 28. incidental or universal? impact on mapping? impact on reasoning? impact on storage?
  29. 29. Distribution Caching? Subgraphs? Payload priority? query- planning?
  30. 30. Provenance Representation? From provenance to trust? (Re)construction? knowledge about knowledge?
  31. 31. Dynamics Streams? Incremental reasoning? Non- monotonicity? versioning?
  32. 32. Errors & noise Maximally consistent subsets? Fuzzy Semantics? Uncertainty Semantics? Rough Semantics? Modules? Repair? Argumentation?
  33. 33. Maximally consistent subsets? Modules? Repair? Argumentation? Fuzzy Semantics? Uncertainty Semantics? Rough Semantics? Streams? Incremental reasoning? Non- monotonicity? versioning? Representation? From provenance to trust? (Re)construction? knowledge about knowledge? Caching? Subgraphs? Payload priority? incidental or universal? impact on mapping? impact on reasoning? impact on storage? Socio- economic first to market market- share
  34. 34. Methodological Hobby horse
  35. 35. Laws about the physical universe Laws about the information universe ?
  36. 36. knowledge follows a long-tail Law: F = - r
  37. 37. Law: |T|<< |A| T = terminological knowledge A = assertional knowledge
  38. 38. Dataset Closure of T Closure of T + A Ratio LUBM 8sec 1h15min 562 Linked Life Data 332sec 1h05min 11 FactForge 89sec 2h45min 111 We don’t have any good laws on complexity

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