2011 05-02 linked data intro
- 1. Aristotle University, Department of Mathematics Master in Web Sciencesupported by Municipality of VeriaFrom Gore’s information highways to Obama’s Linked dataΜιχάλης Βαφόπουλος
- 2. From Al Gore (internet highways) to Barack Obama (linked data)2
- 3. The Web of DocumentsAnalogy:a global file system
- 4. Designed for: human consumption
- 6. Links between: documents(or sub-parts of)
- 7. Degree of structure in objects: fairly low
- 8. Semantics of content and links: implicit (humans)(Tom Heath)The web = the internet+ links + documents3
- 9. The Web of DocumentsSimple, big and unstructured
- 10. Organized in SilosBut humans are interested in:Things, no documents and
- 11. these Thingsmight bein documents or elsewhereHumans: Limited capacity to extract meaning...4
- 12. Limited SEARCH capacitySearch for: Football Players who went to the University of Texas at Austin, played for the Dallas Cowboys as Cornerback(Juan F. Sequeda)5
- 13. Google, Bing, yahoo! irrelevant6
- 14. Wikipedia through LD: relevant7
- 15. The Web of DataAnalogy:a global filesystem----> globaldatabase
- 16. Designed for: human consumption ->machines first, humans later
- 17. Primary objects: documents --> things (or descriptions of things)
- 18. Links between: documents--> things
- 19. Degree of structure in objects: fairly low ---> high
- 20. Semantics of content and links: implicit --> explicit(Tom Heath)8
- 21. The Modigliani TestShow me all the locations of all the original paintings of ModiglianiDaniel Koller (@dakoller) showed that you can find this with a SPARQL query on DBpediaThanks Richard MacManus - ReadWriteWeb
- 23. Results of the Modigliani TestAtanas Kiryakov from OntotextUsed LDSR – Linked Data Semantic RepositoryDbpediaFreebaseGeonamesUMBELWordnetPublished April 26, 2010: http://www.readwriteweb.com/archives/the_modigliani_test_for_linked_data.php
- 25. The Web of Data: why?– encourages reuse– reduces redundancy– maximises its (real and potential) inter-connectedness– enables network effects to add value to data13
- 26. The Web of Data: how?– current state on the WebRelational Databases
- 27. APIs
- 28. XML
- 29. CSV
- 30. XLS(see EXHIBIT)Computers can’t consume data because:Different formats & models
- 32. The Web of Data: how?– we need to create a standard way of publishing Data on the Web (like HTML for docs)This is the Resource Description Framework (RDF)(a simple example here from Juan F. Sequeda), more next semester!)15
- 33. Resource Description Framework (RDF)A data model
- 34. A way to model data
- 35. Inspired form Relational databases and Logic
- 36. RDF is a triple data model
- 37. Labeled Graph (semantic networks)
- 38. Subject, Predicate, Object<Isidoro> <was born in> <Chios><Chios> <is part of> <Greece>
- 39. The RDF Data ModelTriplessubject -> predicate -> objectTom -> worksFor -> TalisTalis -> basedIn -> Birmingham<uri> -> <uri> -> <uri> or "literal"
- 40. παράδειγμα“Talis is Based Near Birmingham”<http://dbpedia.org/resource/Talis_Group><http://xmlns.com/foaf/0.1/based_near><http://sws.geonames.org/3333125/>
- 42. Example: Document on the Web
- 43. Databases back up documentsTHINGS have PROPERTIES:A Book as a Title, an author, …This is a THING:A book title “Programming the Semantic Web” by Toby Segaran, …
- 44. Data representation in RDFProgramming the Semantic WebtitleauthorbookToby Segaranisbn978-0-596-15381-6publishernamePublisherO’Reilly
- 45. Everything on the web is identified by a URI!
- 46. link the data to other dataProgramming the Semantic Webtitleauthorhttp://…/isbn978Toby Segaranisbn978-0-596-15381-6publishernamehttp://…/publisher1O’Reilly
- 47. consider the data from Revyu.comhasReviewhttp://…/review1http://…/isbn978descriptionreviewerAwesome Bookhttp://…/reviewernameJuan Sequeda
- 48. start to link datahasReviewhttp://…/review1http://…/isbn978Programming the Semantic WebtitledescriptionsameAshasReviewerAwesome Bookauthorhttp://…/isbn978Toby Segaranhttp://…/reviewernameisbn978-0-596-15381-6Juan Sequedapublishernamehttp://…/publisher1O’Reilly
- 49. Juan Sequeda publishes data toohttp://juansequeda.com/idhttp://dbpedia.org/AustinlivesInnameJuan Sequeda
- 50. Let’s link more datahasReviewhttp://…/review1http://…/isbn978descriptionhasReviewerAwesome Bookhttp://…/reviewernameJuan SequedasameAshttp://juansequeda.com/idhttp://dbpedia.org/AustinlivesInnameJuan Sequeda
- 51. And morehasReviewhttp://…/review1http://…/isbn978Programming the Semantic WebtitledescriptionsameAshasReviewerAwesome Bookauthorhttp://…/isbn978Toby Segaranhttp://…/reviewernameisbn978-0-596-15381-6Juan SequedapublishersameAshttp://…/publisher1nameO’Reillyhttp://juansequeda.com/idhttp://dbpedia.org/AustinlivesInnameJuan Sequeda
- 52. Linked data = internet + http + RDF
- 53. Linked Data PrinciplesUse URIs as names for thingsUse URIs so that people can look up (dereference) those names.When someone looks up a URI, provide useful information.Include links to other URIs so that they can discover more things.
- 54. Web as a databaseLinked Data makes the web exploitable as ONE GIANT HUGE GLOBAL DATABASE!Is there any query language like sql?SPARQL… (next semester)
- 55. History of LDLinked Data Design Issues by TimBL July 2006
- 56. Linked Open Data Project WWW2007
- 57. First LOD Cloud May 2007
- 58. 1st Linked Data on the Web Workshop WWW2008
- 60. How to Publish Linked Data Tutorial ISWC2008
- 61. BBC publishes Linked Data 2008
- 62. 2nd Linked Data on the Web Workshop WWW2009
- 63. NY Times announcement SemTech2009 - ISWC09
- 64. 1st Linked Data-a-thon ISWC2009
- 65. 1st How to Consume Linked Data Tutorial ISWC2009
- 66. Data.gov.uk publishes Linked Data 2010
- 67. 2st How to Consume Linked Data Tutorial WWW2010
- 68. 1st International Workshop on Consuming Linked Data COLD2010
- 71. What is a Linked Data application/service?Software system that makes use of data on the Web from multiple datasets and that benefits from links between the datasets
- 72. Characteristics of Linked Data ApplicationsConsume data that is published on the web following the Linked Data principles: an application should be able to request, retrieve and process the accessed data
- 73. Discover further information by following the links between different data sources: the fourth principle enables this.
- 74. Combine the consumed linked data with data from sources (not necessarily Linked Data)
- 75. Expose the combined data back to the web following the Linked Data principles
- 76. Offer value to end-usersthe 5 stars of open linked data★make your stuff available on the Web (whatever format)★★make it available as structured data (e.g. excel instead of image scan of a table)★★★non-proprietary format (e.g. csv instead of excel)★★★★use URLs to identify things, so that people can point at your stuff★★★★★link your data to other people’s data to provide contexthttp://lab.linkeddata.deri.ie/2010/star-scheme-by-example/
- 80. Greece – not in Linked Data!
- 82. Fuelprices.gr
- 83. E-prices.gr
- 85. 41