The document provides an overview of the Semantic Web and linked data. It defines the Semantic Web as publishing structured data on the web in a format that computers can understand, rather than just documents. Linked data follows principles like using URIs to identify things and linking data across sources to integrate information. Query languages like SPARQL can then be used to search across linked data. Examples show how data can be published as RDF and linked to create a global database. Applications that consume and combine linked data from multiple sources are discussed.

1. What is the Semantic Web?Juan F. SequedaDepartment of Computer ScienceUniversity of Texas at AustinApril 2011

2. How many people are familiar withHTMLCSSBrowserHTTPXMLJSONRDFOWLSPARQL

4. What is the Web?

5. What is the Web?“… the Web, is a system of interlinked hypertext documents accessed via the Internet. With a web browser, one can view web pages that may contain text, images […] and navigate between them via hyperlinks”http://en.wikipedia.org/wiki/World_Wide_Web

6. Current Web = internet + links + docs

7. History of the WebCreated by Tim Berners-Lee at CERN in 1989Mosaic browser in 1993W3C created in 1994Exponential growth mid 90sSearch engines – Google 1998Dot-com boom 1999 – 2001Web 2.0 – blogs, Facebook, Twitter, etc

8. What is the problem?The web is full of documentsWe aren’t always interested in documentsWe are interested in THINGSThese THINGS might be in documentsWe can read a HTML document rendered in a browser and find what we are searching forThis is hard for computers. Computers have to guess (even though they are pretty good at it)

9. The Web is a Data ShredderStructured DataUnstructured DataThanks Martin Hepp

10. What would we like?Make it easy for computers/software to find THINGS

11. Do you SEARCH or do you FIND?

12. Search forFootball Players who went to the University of Texas at Austin, played for the Dallas Cowboys as Cornerback

16. Why can’t we just FIND it…

19. Guess how I FOUND out?

20. Semantic Web!

21. What is the Semantic Web?Besides publishing documents on the webwhich computers can’t understand easilyLet’s publish on the web something that computers can understand

22. What is the Semantic Web?Besides publishing documents on the webwhich computers can’t understand easilyLet’s publish on the web something that computers can understandDATA

23. The Semantic Web is a web of linked dataThe current web is a web of linked documents

24. But wait… doesn’t the web already have data?

25. Current Data on the WebRelational DatabasesAPIsXMLCSVXLS…Can’t computers and applications already consume that data on the web?

26. True! But it is all in different formats and data models!

27. This makes it hard to integrate data

28. The data in different data sources aren’t linked

29. For example, how do I know that the Juan Sequeda in Facebook is the same as Juan Sequeda in Twitter

30. Or if I create a mashup from different services, I have to learn different APIs and I get different formats of data back

31. Data is Siloed

32. Wouldn’t it be great if we had a standard way of publishing data on the Web?

33. We have a standardized way of publishing documents on the web, right?HTML

34. Then why can’t we have a standard way of publishing data on the Web?

35. Good question! And the answer is YES. There is!RDF

36. Resource Description Framework (RDF)A data model A way to model datai.e. Relational databases use relational data modelRDF is a triple data modelLabeled GraphSubject, Predicate, Object<Juan> <was born in> <California><California> <is part of> <the USA><Juan> <has hobby> <Salsa dancing>

37. RDF can be serialized in different waysRDF/XMLRDFa (RDF in HTML)N3TurtleJSON

38. So does that mean that I have to publish my data in RDF now?

39. You don’t have to… but we would like you to 

40. An example

41. Document on the Web

42. 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, …

43. Lets represent the data in RDFProgramming the Semantic WebtitleauthorbookToby Segaranisbn978-0-596-15381-6publishernamePublisherO’Reilly

44. Remember that we are on the webEverything on the web is identified by a URI

45. And now let’s link the data to other dataProgramming the Semantic Webtitleauthorhttp://…/isbn978Toby Segaranisbn978-0-596-15381-6publishernamehttp://…/publisher1O’Reilly

46. And now consider the data from Revyu.comhasReviewhttp://…/review1http://…/isbn978descriptionreviewerAwesome Bookhttp://…/reviewernameJuan Sequeda

47. Let’s start to link datahasReviewhttp://…/review1http://…/isbn978Programming the Semantic WebtitledescriptionsameAshasReviewerAwesome Bookauthorhttp://…/isbn978Toby Segaranhttp://…/reviewernameisbn978-0-596-15381-6Juan Sequedapublishernamehttp://…/publisher1O’Reilly

48. Juan Sequeda publishes data toohttp://juansequeda.com/idhttp://dbpedia.org/AustinlivesInnameJuan Sequeda

49. Let’s link more datahasReviewhttp://…/review1http://…/isbn978descriptionhasReviewerAwesome Bookhttp://…/reviewernameJuan SequedasameAshttp://juansequeda.com/idhttp://dbpedia.org/AustinlivesInnameJuan Sequeda

50. 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

51. Data on the Web that is in RDF and is linked to other RDF data is LINKED DATA

52. Linked Data PrinciplesUse URIs as names for thingsUse HTTP 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.

53. Linked Data makes the web appear as ONEGIANTHUGEGLOBALDATABASE!

54. I can query a database with SQL. Is there a way to query Linked Data with a query language?

55. Yes! There is actually a standardize language for thatSPARQL

56. FIND all the reviews on the book “Programming the Semantic Web” by people who live in Austin

57. hasReviewhttp://…/review1http://…/isbn978Programming the Semantic WebtitledescriptionsameAshasReviewerAwesome Bookauthorhttp://…/isbn978Toby Segaranhttp://…/reviewernameisbn978-0-596-15381-6Juan SequedapublishersameAsnamehttp://…/publisher1O’Reillyhttp://juansequeda.comhttp://dbpedia.org/AustinlivesInnameJuan Sequeda

58. This looks cool, but let’s be realistic. What is the incentive to publish Linked Data?

59. What was your incentive to publish an HTML page in 1990?

60. 1) Share data in documents2) Because you neighbor was doing it… later on …3) Marketing, Advertising, SEO

61. So why should we publish Linked Data in 2011?

62. 1) Share data as data2) Because you neighbor is doing it…3) (Semantic) SEO ++

63. Linked Data PublishersUK GovernmentUS GovernmentBBCOpen Calais – Thomson ReutersFreebase/GoogleNY TimesBest BuyCNETDbpediaOverstock.comO’Reilly Media…

64. Publishing Linked DataLegacy Data in Relational DatabasesD2R Server, Virtuoso, Triplify, UltrawrapCMSDrupal 7Native RDF DatabasesAllegroGraph, Jena, Sesame, Virtuoso, Talis PlatformIn HTML with RDFa

65. Links to other URIs

66. <span rel="foaf:interest"><a href="http://dbpedia.org/resource/Database" property="dcterms:title">Database</a>,<a href="http://dbpedia.org/resource/Data_integration" property="dcterms:title">Data Integration</a>,<a href="http://dbpedia.org/resource/Semantic_Web" property="dcterms:title">Semantic Web</a>,<a href="http://dbpedia.org/resource/Linked_Data" property="dcterms:title">Linked Data</a>,etc.</span>

67. (Semantic) SEO ++Markup your HTML with RDFaUse standard vocabularies (ontologies)Google VocabularyGood RelationsDublin CoreGoogle and Yahoo will crawl this data and use it for better rendering

69. May 2007

70. Oct 2007

71. Nov 2007

72. Feb 2008

73. Mar 2008

74. Sept 2008

75. Mar 2009 (1)

76. Mar 2009 (2)

77. July 2009

78. September 2010

79. April 2011YOU GET THE PICTUREITS BIG and getting BIGGER andBIGGER

80. Now what can we do with this data?

81. Query it!

82. Find all the locations of all the original paintings of Modigliani

83. Linked Data Browsers

84. Linked Data BrowsersNot actually separate browsers. Run inside of HTML browsersView the data that is returned after looking up a URI in tabular form(IMO) No usability

86. Linked Data BrowsersTabulatorhttp://www.w3.org/2005/ajar/tabOpenLinkhttp://ode.openlinksw.com/ZitgistDataviewrhttp://dataviewer.zitgist.com/Marbleshttp://www5.wiwiss.fu-berlin.de/marbles/Exploratorhttp://www.tecweb.inf.puc-rio.br/explorator

87. Faceted Browsers

88. http://dbpedia.neofonie.de

89. http://dev.semsol.com/2010/semtech/

90. On-the-fly Mashups

91. http://sig.ma

92. What’s next?

93. Time to create new and innovative ways to interact with Linked DataNew and improved search

94. This may be one of the Killer Apps that we have all been waiting forhttp://en.wikipedia.org/wiki/File:Mosaic_browser_plaque_ncsa.jpg

95. It’s time to partner with HCI communitySemantic Web UIs don’t have to be ugly

96. Linked Data ApplicationsSoftware system that makes use of data on the web from multiple datasets and that benefits from links between the datasets

97. 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

98. Discover further information by following the links between different data sources: the fourth principle enables this.

99. Combine the consumed linked data with data from sources (not necessarily Linked Data)

100. Expose the combined data back to the web following the Linked Data principles

101. Offer value to end-usersSemantic Web technologies integrate data across boundaries"National Instruments is currently releasing an internal system based on an RDF triple store. This technology provides increased flexibility and agility in managing and accessing data for our complex and ever-evolving product offerings. With RDF powering one of our key information delivery infrastructures, we will enable greater capabilities at lower total cost that what we have seen with any competing platform."

102. RiBS - Miranker LabUltrawrapVirtualizes a RDBMS as Graph (RDF)Automatically generate the ontology from schemaQuery a RDBMS in SPARQL (language for RDF)Leverage SQL optimizer to do all the hard workInsert arbitrary RDF to your RDBMS without altering schema DiamondLinked Data query engineLinked Traversal based query executionStart with a URI that returns RDF and follow links

103. Ultrawrap enables your RDBMS to be linked with other RDF dataUltrawrapUltrawrapSpecifyUltrawrapNOW WE WANT TO QUERY THISMorphsterMorphbank

104. Query the Web of Linked Data with DiamondSPARQLQueryDiamondUltrawrapUltrawrapSpecifyUltrawrapMorphsterMorphbank

105. Example 1 (Specify – DBpedia)Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/taxon51807#thingAND fin any subjects it may have “skos:subject”

106. Result Example 1Note that http://dbpedia.org/resource/Category:Fish_of_Australia comes from a different data source (dbpedia.org)

107. Example 2 (Specify-Morphbank)Get full name and guid from taxon with id http://tata.csres.utexas.edu:8080/specify/data/taxon42947#thingAND the rank and kingdom from Morphbank