- 1. Semantic Web Overview Open Data Group 23 rdFeb 2011 @ianibbo
This work is licensed under a Creative Commons Attribution 3.0
Unported License.
2. Overview
- Scene Setting
- Questions you should be able to answer at the end
- Major Aspects & Building Blocks
- Conceptual Model and Vision
- The (Distributed) Graph Model 3. My ability to describe what I
know 4. Your ability to ask me questions
- Details
- Descriptions & Descriptive Bindings - RDF
- RDFXML, RDFa, n3, turtle, ntriples
- Storage 5. Retrieval
6. Scene Setting (1)
- Semantic Web
- Whats it good for?
- Anyone can say anything about anything (And thats a good thing!
(?)) 7. Ability to describe unforeseen classes 8. The real goal
- Collect facts from lots of sources 9. 10. Then ask some
questions
11. Scene Setting (2)
- Semantic Web (Really Semantic Stores)
- Whats it not (so) good for?
- Tabular Data actually not so bad 12. Updating Group Operations
on Tabular Data more of an issue 13. Frequent/atomic/isolated
Updates (anecdotally) 14. Transactional Capabilities 15. Modern
Search Capabilities Spatial, Text, other. 16. Identity
Generation
- How to know the difference? 17. Coordinationisstill needed This
is not a free-for-all Honest! 18. Provenance of data sets (Resource
provenance good)
19. Conceptual Model - Examples
- 20. 21. '23-Feb-2011#date' 22. 23. '70#int' 24. 25. 26.
27. Conceptual Model - Principles
- URI, URI, URI, URI 28. ISBN's, ISSNs - urn:issn:1535-3613 29.
The description and the thing described are not the same thing
- Well known strategies for modelling.
- == http://ianibbo.me 30. == http://ianibbo.me#me
- 31.
32. Conceptual Model (Details)
- Formally
- http://www.slideshare.net/ianibbo/gist-od2feb2011 33.
http://purl.org/dc/elements/1.1/creator 34.
Http://ianibbo.me#me
- Namespaces
35. Details Descriptions & Descriptive Bindings - RDFXML
- A common syntax, to which words can be easily added. 36.
Understood over the internet 37. Descriptions which can be used in
many different ways
38. Details Descriptions & Descriptive Bindings - RDFXML
Rose Bush A Guide to Growing Roses Describes process for planting
and nurturing different kinds of rose bushes.2001-01-20 39. Details
Descriptions & Descriptive Bindings - RDFa
The trouble with Bob Alice ...
Jo's Barbecue Eve ...
40. Details Storage Triple Stores & Quad Stores
- Why
- Once you have a description in your hand....
- Temporary or Permanent 41. Updates / Static 42. Public /
Private 43. Provenance 44. What is a triple/quad store, why is it
special 45. RDF Changesets
46. Details Query Languages & Servers - SPARQL
- A SPARQL Query
- Prefix declarations, for abbreviating URIs 47. Dataset
definition, stating what RDF graph(s) are being queried 48. A
result clause, identifying what information to return from the
query 49. The query pattern, specifying what to query for in the
underlying dataset 50. Query modifiers, slicing, ordering, and
otherwise rearranging query results
51. Details Query Languages & Servers - SPARQL PREFIX foo:
... # dataset definition FROM ... # result clause SELECT ... #
query pattern WHERE { ... } # query modifiers ORDER BY ... 52.
Details Query Languages & Servers - SPARQL prefix sch-ont:
prefix spatial: SELECT ?name ?district ?postcode ?lat ?long
?openDate ?email ?urbanRural ?ratio WHERE { ?school a
sch-ont:School; sch-ont:establishmentName ?name;
sch-ont:districtAdministrative ?district;
sch-ont:districtAdministrative . OPTIONAL { ?school
sch-ont:openDate ?openDate; } OPTIONAL { ?school spatial:long
?long; } OPTIONAL { ?school spatial:lat ?lat; } OPTIONAL { ?school
sch-ont:SCUpreferredemail ?email; } OPTIONAL { ?school
sch-ont:urbanRural ?urbanRural; } OPTIONAL { ?school
sch-ont:pupilTeacherRatio ?ratio; } } ORDER BY ?name
http://services.data.gov.uk/education/sparql 53. The coolest thing
done with your datawill be done by somebody else. Semantic Web
should make this much less painful for that somebody else 54.
Things not covered
- Reification 55. Inferencing
56. Notes
- http://www.w3.org/2002/12/rdf-identifiers/ 57.
http://www.cambridgesemantics.com/2008/09/sparql-by-example/