1. Aristotle University, Department of Mathematics Master in Web Science supported by Municipality of Veria From Gore’s information highways to Obama’s Linked data Μιχάλης Βαφόπουλος

2. From Al Gore (internet highways) to Barack Obama (linked data) 2

4. Designed for: human consumption

5. Primary objects: documents

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 + documents 3

12. Limited SEARCH capacity Search 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! irrelevant 6

14. Wikipedia through LD: relevant 7

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 Test Show me all the locations of all the original paintings of Modigliani Daniel Koller (@dakoller) showed that you can find this with a SPARQL query on DBpedia Thanks Richard MacManus - ReadWriteWeb

23. Results of the Modigliani Test Atanas Kiryakov from Ontotext Used LDSR – Linked Data Semantic Repository Dbpedia Freebase Geonames UMBEL Wordnet Published 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 data 13

27. APIs

28. XML

29. CSV

31. Not inter-connected14

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

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 Model Triples subject -> predicate -> object Tom -> worksFor -> Talis Talis -> 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 documents THINGS 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 RDF Programming the Semantic Web title author book Toby Segaran isbn 978-0-596-15381-6 publisher name Publisher O’Reilly

45. Everything on the web is identified by a URI!

46. link the data to other data Programming the Semantic Web title author http://…/isbn978 Toby Segaran isbn 978-0-596-15381-6 publisher name http://…/publisher1 O’Reilly

47. consider the data from Revyu.com hasReview http://…/review1 http://…/isbn978 description reviewer Awesome Book http://…/reviewer name Juan Sequeda

48. start to link data hasReview http://…/review1 http://…/isbn978 Programming the Semantic Web title description sameAs hasReviewer Awesome Book author http://…/isbn978 Toby Segaran http://…/reviewer name isbn 978-0-596-15381-6 Juan Sequeda publisher name http://…/publisher1 O’Reilly

49. Juan Sequeda publishes data too http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

50. Let’s link more data hasReview http://…/review1 http://…/isbn978 description hasReviewer Awesome Book http://…/reviewer name Juan Sequeda sameAs http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

51. And more hasReview http://…/review1 http://…/isbn978 Programming the Semantic Web title description sameAs hasReviewer Awesome Book author http://…/isbn978 Toby Segaran http://…/reviewer name isbn 978-0-596-15381-6 Juan Sequeda publisher sameAs http://…/publisher1 name O’Reilly http://juansequeda.com/id http://dbpedia.org/Austin livesIn name Juan Sequeda

52. Linked data = internet + http + RDF

53. Linked Data Principles Use URIs as names for things Use 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 database Linked Data makes the web exploitable as ONE GIANT HUGE GLOBAL DATABASE!Is there any query language like sql?SPARQL… (next semester)

56. Linked Open Data Project WWW2007

57. First LOD Cloud May 2007

58. 1st Linked Data on the Web Workshop WWW2008

59. 1stTriplification Challenge 2008

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

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

78. http://wheredoesmymoneygo.org/

79. http://energy.publicdata.eu/ee/vis.html

80. Greece – not in Linked Data!

81. http://geodata.gov.gr/geodata/

82. Fuelprices.gr

83. E-prices.gr

85. 41

86. More Examples http://data-gov.tw.rpi.edu/wiki http://dbrec.net/ http://fanhu.bz/ http://data.nytimes.com/schools/schools.html http://sig.ma http://visinav.deri.org/semtech2010/