Semantic Web Technologies - 01 - From Internet to the Web of Data

1. Semantic Web Technologies Lecture Dr. Harald Sack Hasso-Plattner-Institut für IT Systems Engineering University of Potsdam Winter Semester 2012/13 Lecture Blog: http://semweb2013.blogspot.com/ This ﬁle is licensed under the Creative Commons Attribution-NonCommercial 3.0 (CC BY-NC 3.0)Donnerstag, 18. Oktober 12

2. Semantic Web Technologies Content2 1. Introduction 2. Semantic Web - Basic Architecture Languages of the Semantic Web - Part 1 3. Knowledge Representation and Logics Languages of the Semantic Web - Part 2 4. Applications in the ,Web of Data‘ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

3. Semantic Web Technologies Content3 1. Introduction • From Internet to Web 2.0 ...from a historical point of view • Quo Vadis WWW? ...the limits of the WWW • Semantic Web ...towards an ,intelligent‘ WWW • Semantic Web Applications ...the semantic WWW begins Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

4. 4 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

5. Semantic Web Technologies Content5 J.C.R. Licklider Robert Taylor Larry Roberts ARPA IPTO Director ARPA IPTO Director ARPA IPTO Chief Scientist (1962-1964) (1966-1969) (1966-1973) "[...] we are entering a technological age in which we will be able to interact with the richness of living information - not merely in the passive way that we have been accustomed to using books and libraries, but as active participants in an ARPANET ongoing process, bringing something to 29. October 1969 it through our interaction with it, and not simply receiving something from it by our connection to it." J.C.R. Licklider, Robert Taylor: "The Computer as a Communication Device". Science and Technology 76, pp. 21-31, April 1968. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

6. Semantic Web Technologies From Internet to Web 2.06 Es war einmal....das Internet Larry Roberts ARPA IPTO Chief Scientist (1966-1973) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

7. First Generation: The Internet Computer Centered Processing7 • How did the user get the information? 1. open terminal 2. connect to remote computer 3. retrieve file system data from remote computer 4. download file from remote to local computer 5. read file on local computer Problem: • Information access requires expert knowledge • Information access is expensive... • Information Retrieval is very expensive... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

8. 8 Tim Berners-Lee Robert Cailliau The World Wide Web was born at the European Nuclear Research Center CERN in 1990... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

9. Second Generation: The Web Document Centered Processing9 • How did the user get the information? Dokument Dokument Dokument nk Hyperli Hyp erlin k k rlin pe Hy Hy pe k Dokument rlin rli n k pe Hy Dokument Hyp erlin k 1. open browse r 2. load docume nt 3. click on next hyperlink 4. ... Advantages: • No expert knowledge required • Simple information access • Information retrieval via search engines Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

10. • But the original idea behind the WWW is much older.....10 Denis Diderot (1713-1784) Jean-Baptiste le Rond dAlembert (1717-1783) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

11. 11 Agostino Ramelli (1588), Le diverse et artiﬁciose machine; composte in lingua Italiana et Francese Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

12. 11 y. ..? il it Usab Agostino Ramelli (1588), Le diverse et artiﬁciose machine; composte in lingua Italiana et Francese Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

13. Vannevar Bush proposed the ﬁrst Hypertext-System „MEMEX“ in 194512 Vannevar Bush (1890-1974) vgl. Vannevar Bush, As we may think , Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität Potsdam The Atlantic Monthly, 1945, JulyDonnerstag, 18. Oktober 12

14. Why was the Web such a big success ? Lynx 199313 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

15. Why was the Web such a big success ? NCSA Mosaic 199414 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

16. Why was the Web such a big success ? IPad15 Safari 2010 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

17. There seem to be no Limits of Growth...16 http://www.isc.org/ (Stand: 10/2012) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

18. From Web 1.0 to Web 2.0 Web Content and Applications are Changing17 Information Consumption 908,585,739 Information Production Interactive Participation Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

19. Web 2.0 is theWeb Content and Roles are Changing... business revolu tion in the computer in dustry caused by the move to18 the Internet as platform, and a n attempt to und erstand the rules for su ccess on that new pla tform " -- Tim OReilly, 2003 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

21. How can we ﬁnd something in the Web?20 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

22. current solution:21 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

23. 22 The Web is big. Really big. You just wont believe how vastly, hugely, mind-bogglingly big it is. (...according to Douglas Adams) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

24. 23 The Web is really big... •ca. 25 x 109 indexed documents in search engines (TNL Blog: Google has 24 billion items index, considers MSN search nearest competitor, September 2005) •Web Crawler: > 1012 (1 trillion) documents (The Ofﬁcial Google Blog: We knew the Web was Big....., Juli 25, 2008) •Google Search Index Caffeine comprises ca.100 Million Gigabytes i.e. 1017 Byte (SMX Video: Google’s Matt Cutts On Caffeine Launch, June 9, 2010, http://searchengineland.com/smx-video-googles-matt-cutts-on-caffeine-launch-43933) •DeepWeb (Darkweb) estimated to be about 550 times bigger than Surface Web (Bergman, 2001) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

25. ...and it‘s getting bigger every minute! Dr. Harald Sack, Hasso-Plattner-Institut Potsdam, Workshop: Interaktion und Visualisierung im Datenweb (IVDW 2012), Braunschweig, 20.09.2012Donnerstag, 18. Oktober 12

26. http://www.visualnews.com/2012/06/19/how-much-data-created-every-minute/ Dr. Harald Sack, Hasso-Plattner-Institut Potsdam, Workshop: Interaktion und Visualisierung im Datenweb (IVDW 2012), Braunschweig, 20.09.2012Donnerstag, 18. Oktober 12

27. http://www.visualnews.com/2012/06/19/how-much-data-created-every-minute/ Dr. Harald Sack, Hasso-Plattner-Institut Potsdam, Workshop: Interaktion und Visualisierung im Datenweb (IVDW 2012), Braunschweig, 20.09.2012Donnerstag, 18. Oktober 12

28. Semantic Web Technologien Quo vadis WWW ?26 Multimedia, Real-Time Data, Sensor Data, .... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

29. Semantic Web Technologien Quo vadis WWW ?27 Multimedia, Real-Time Data, Sensor Data, .... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

30. 28 and all the things will connect with social networks... Vorlesung Semantic Web, Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

32. Information in the WWW29 • what is important and how do you know? • what is information, what is advertisement? • what does the information mean? • how credible/trustworthy is the information? • what belongs together? • what is redundant? • Humans have contextual knowledge, world knowledge and experience to solve the problem Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

33. 30 • The Web is supposed to be used by humans. • The Web is based on the markup language HTML • HTML describes • how information is presented • how information is linked • but not, what the information means Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

35. 32 Semantics Semantics (greek σεμαντικος = pertains to the character, the study of meaning) is part of the linguistics focussed on • Sense and • Meaning of language or symbols of language. It is the study of interpretation of signs or symbols as used by agents or communities within particular circumstances and contexts. Semantics asks, how sense and meaning of complex concepts can be derived from simple concepts based on the rules of syntax. The semantics of a message depends of its context and pragmatics. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

36. 33 Syntax Syntax (greek σψνταξις = Arrangement, Ordering) as in grammatics denotes the study of the principles and processes by which sentences are constructed in particular languages. • In formal Languages, syntax is just a set of rules, by which well formed expressions can be created from a fundamental set of symbols (alphabet). • in computer science, syntax deﬁnes the normative structure of data. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

37. 34 Context Context (lat. contextus = interweaved) denotes the surrounding of a symbol (concept) in an expression resp. its relationship with surrounding expressions (concepts) and further related elements, Contexts denotes all elements of any sort of communication that deﬁne the interpretation of the communicated content, as e.g., • general contexts: place, time, interrelation of action in a message • personal or social contexts: relation between sender and receiver of a message Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

38. Pragmatics35 Pragmatics (greek. πραγμα = action) reﬂects the intention by which the language is used to communicate a message. In linguistics pragmatics denotes the study of applying language in different situations. Pragmatics studies the ways in which context contributes to meaning. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

39. 36 In the (traditional) Web there is no explicit semantics. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

40. 37Problem 1: Information Retrieval Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

41. 37 • traditional keyword-based search leads to many not relevant results • different meanings • polysemy • different contexts • traditional keyword-based search does not ﬁnd all results • synonyms and metaphors • missing context deﬁnitionProblem 1: Information Retrieval Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

42. 38 • can only be solved ,correctly‘ by a human agent • heterogeneous distribution and order of information • Software agent does not have sufﬁcient • knowledge of contexts • world knowledge and • experience • to solve the problem Problem 2: Information Extraction Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

43. 39 Problemfeld 2: Informationsextraktion • implicit knowledge, i.e. information does not have speciﬁed explicitely, but must be derived via logical deductions from available information. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

44. 40 • the more complex and voluminous a website, the more complicated is the maintenance of the only weakly structured data. • Problems: • syntactic and semantic (link) consistency • correctness • timeliness Problem 3: Maintenance Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

45. • Adaption of the presented information content to personal requirements41 • Problems: • from where do we get the required (personal) information? • personalization vs. data security Problem 4: Personalization Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

46. 42 GAME OVER Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

48. From World Wide Web to the Web of Data44 „The Web was designed as an information space, with the goal that it should be useful not only for human-human communication, but also that machines would be able to participate and help… “ Tim Berners-Lee, Semantic Web Roadmap, Sept 1998 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

49. From World Wide Web to the Web of Data45 Precondition: • Content can be read and interpreted correctly (= „understood“) by machines Natural Language Processing • Technologies of traditional Information Retrieval (Search Engines) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

50. From World Wide Web to the Web of Data46 Precondition: • Content can be read and interpreted correctly (= „understod“) by machines Natural Language Processing Semantic Web • Technologies of traditional • Natural language web content will Information Retrieval be explicitly annotated with (Search Engines) semantic metadata • Semantic metadata encode the Meaning (Semantics) of the content and can be read and interpreted correctly by machines Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

51. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

52. „Understanding“ Content on the Web48 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

53. „Understanding“ Content on the Web49 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

54. „Understanding“ Content on the Web49 Text: „Why snub me, Fab?“ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

55. „Understanding“ Content on the Web49 Text: „Why snub me, Fab?“ • Disambiguation solution of linguistic ambiguities Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

56. „Understanding“ Content on the Web49 Text: „Why snub me, Fab?“ Entity Mapping Disambiguation Fab ? a detergent Fab ? a Canadian gay magazine FAB ? the Film Advisory Board FAB ? Federación Atlética de Bolivia Brazilian Basketball • Disambiguation Fab Melo ? Player solution of linguistic ambiguities Fabrizio Moretti ? Drummer of The Strokes Fabio Capello ? Manager of the UK national Football team Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

57. „Understanding“ Content on the Web50 Text: „Why snub me, Fab?“ Entity Mapping Fabio Capello Entity • The Meaning (Semantics) of entities and classes must be deﬁned explicitly. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

58. „Understanding“ Content on the Web50 Text: „Why snub me, Fab?“ Entity Mapping Fabio Capello Entity is a Soccer Manager Class • The Meaning (Semantics) of entities and classes must be deﬁned explicitly. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

59. „Understanding“ Content on the Web50 Text: „Why snub me, Fab?“ Entity Mapping Fabio Capello Entity is a Soccer Manager Class is subclass of • The Meaning (Semantics) of entities and classes must be deﬁned explicitly. Person Class Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

60. „Understanding“ Content on the Web51 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello (entity) Class- is a membership has class Soccer Manager (class) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

61. „Understanding“ Content on the Web51 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello (entity) Class- is a membership has class Soccer Manager (class) subclass is subclass of is subclass of superclass Person (class) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

62. „Understanding“ Content on the Web (III)52 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello Entities is a Classes Soccer Manager is subclass of Person Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

63. „Understanding“ Content on the Web (III)52 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello Entities is a Classes Soccer Manager is subclass of Person Place birthPlace Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

64. „Understanding“ Content on the Web (III)52 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello San Canzian birthPlace Entities is a Classes Soccer Manager is a is subclass of Person Place birthPlace Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

65. „Understanding“ Content on the Web (III)52 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) Fabio Capello San Canzian birthPlace Entities is a Classes Soccer Manager is a is subclass of Date Person Place birthDate birthPlace Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

66. „Understanding“ Content on the Web (III)52 • The Meaning (Semantics) is expressed with the help of well suited knowledge representations (Ontologies) 1946-06-18 Fabio Capello San Canzian birthDate birthPlace Entities is a Classes Soccer Manager is a is a is subclass of Date Person Place birthDate birthPlace Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

67. What is the Semantic Web?53 „The Semantic Web is an extension of the current web in which information is given well-defined meaning, better enabling computers and people to work in cooperation" Tim Berners-Lee, James Hendler, Ora Lassila: The Semantic Web, Scientific American, 284(5), pp. 34-43(2001) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

68. The Semantic Web - a Web of Data54 •The Meaning of Information (Semantics) is made explicit by formal (structured) and standardized knowledge representations (Ontologies). • Thus it will be possible, •to process the meaning of information automatically •to relate and integrate heterogeneous data •to deduce implicite (not evident) information from existing (evident) information in an automated way The Semantic Web is kind of a global database that contains a universal network of semantic propositions. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

69. Semantic Web ...towards an „intelligent“ Web55 Das Semantic Web • Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

70. Semantic Web ...towards an „intelligent“ Web56 URI - Uniform Resource Identifier Fabio Capello http://dbpedia.org/resource/Fabio_Capello Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

71. Semantic Web ...towards an „intelligent“ Web57 http://de.wikipediapedia.org/wiki/Fabio Capello http://dbpedia.org/resource/Fabio_Capello Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

72. Semantic Web ...towards an „intelligent“ Web http://dbpedia.org/resource/Fabio_Capello58 Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

73. Semantic Web ...towards an „intelligent“ Web59 http://dbpedia.org/resource/Fabio_Capello :Fabio_Capello dbpp:birthPlace :San_Canzian . :Fabio_Capello dbpp:birthDate “1946-06-18“ . :Fabio_Capello rdfs:type dbpo:SoccerManager . :Fabio_Capello rdfs:type dbpo:Person . ... RDF Resource Description Framework :Fabio_Capello rdf:type dbpo:SoccerManager . RDF Tripel RDF Subject RDF Property RDF Object Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

74. Semantic Web ...towards an „intelligent“ Web60 http://dbpedia.org/ontology/SoccerManager dbpo:SoccerManager rdf:type owl:class . dbpo:SoccerManager rdfs:subClassOf dbpo:Person . dbpo:SoccerManager rdfs:label “SoccerManager“ . dbpp:birthPlace rdf:type rdf:Property . dbpp:birthPlace rdfs:domain dbpo:Person . dbpp:birthPlace rdfs:range dbpo:Place . dbpp:birthDate rdf:type rdf:Property . dbpp:birthDate rdfs:domain :Person . dbpp:birthDate rdfs:range xsd:date . ... RDF Schema SoccerManager is subclass of Date Person Place birthDate birthPlace Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

75. Semantic Web ...towards an „intelligent“ Web61 1946-06-18 Fabio Capello birthDate entities classes is a is a LivingPeople ∩ DeadPeople =∅ is subclass of is subclass of logical constraint Date Person birthDate ∀x.∃y.hasDeathDate(x,y) ∧ Person(x) ∧ Date(y) + Rules → DeadPeople(x) (Description Logics) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

76. Semantic Web ...towards an „intelligent“ Web62 Look for all Soccer Players that have scored more than 10 goals as member of a national team. SELECT DISTINCT ?l ?l2 ?g FROM <http://dbpedia.org> WHERE { ?s rdf:type dbpo:SoccerPlayer . ?s dbpp:nationalteam ?o . ?s rdfs:label?l FILTER langMatches( lang(?l), "EN" ) . ?s dbpp:nationalgoals ?g FILTER(?g>10). ?s dbprop:nationalteam ?nat . ?nat rdfs:label ?l2 FILTER langMatches( lang(?l2), "EN" ) . } ORDER BY DESC(?g) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

77. Semantic Web ...towards an „intelligent“ Web63 Look for all Soccer Players that have scored more than 10 goals as member of a national team. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

78. Semantic Web ...towards an „intelligent“ Web64 Look for all Soccer Players that have scored more than 10 goals as member of a national team. Problem: Data Quality.... Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

80. Semantic Web Technologies Semantic Web Applications66 Linked Data □ Linked Open Data (LOD) denote publicly available (RDF) Data in the Web, identiﬁed via URI and accessable via HTTP. Linked data link to other data via URI. The ,Web of Data‘ • >31 billion facts • >500 million links (Oct. 2011) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

81. 67 http://www.bbc.co.uk/music Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

82. What is so special about the BBC68 Music Website? • Information is dynamically aggregated from external, publicly available data (Wikipedia, MusicBrainz,...) • no Screen Scraping • no specialized API • data available als Linked Open Data • data access via simple HTTP Request • data is always up-to-date without manual interaction Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

83. Search Engines - Document Retrieval69 •Search Engine Query String: “Jaguar of 2000“ Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

84. Search Engines - Document Retrieval69 •Search Engine Query String: “Jaguar of 2000“ • Reﬁne ,jaguar‘ CAR or ANIMAL or OPERATINGSYSTEM etc. ? Reﬁne: CAR Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

85. Search Engines - Document Retrieval70 •Search Engine Query String: “Jaguar of 2000“ • Name: Jaguar E Type • Category: Car • ... • ConstructionYear <Integer> • technicalParameter • CylinderCapacity <Integer> • Power <Integer> • ... • ... Knowledge Representation (Ontologie, Linked Data) Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

86. Search Engines - Document Retrieval70 •Search Engine Query String: “Jaguar of 2000“ • Name: Jaguar E Type • Category: Car • ... • ConstructionYear <Integer> • technicalParameter • CylinderCapacity <Integer> • Power <Integer> • ... • ... Knowledge Representation • Reﬁne ,2000‘ (Ontologie, Linked Data) ConstructionYear or technicalParameter ? Reﬁne: ConstructionYear Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

87. Search Engines - Document Retrieval71 • General Problems: • correct interpretation of query string • correct identiﬁcation of entities • automatic disambiguation • usability • personalization Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

88. Search Engines - Fact Retrieval72 •Query String: “Where can I ﬁll up the tank at a considerable discount?“ Answer : - Hohenfelden, xy-Str. 32 -> Super leaded, 1,99 € - fuel-efﬁcient route will be passed to navigation - drive only at half throttle for saving fuel… Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

89. Search Engines - Exploratory Search dbpedia:Michael_Collins73 dbpedia-owl:mission dbpedia:Apollo_11 dbpedia-owl:mission dcterms:subject dbpedia-owl:mission dbpedia:Neil_Armstrong dbpedia:Buzz_Aldrin dcterms:subject category:Apollo_program dbpedia:Apollo_13 rdf:type dbpedia:Space_Shuttle_Challenger yago:Space_accidents_and_incidents rdf:type Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

90. Intelligent Agents in the Semantic Web74 WWW User presentation service retrieval service (e.g. Firefox) (e.g. Google) WWW documents Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

91. Intelligent Agents in the Semantic Web74 WWW Semantic Web User User personal assistant intelligent infrastructure presentation service retrieval service services (e.g. Firefox) (e.g. Google) WWW documents WWW documents Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

92. 3 Generations of Web Documents75 static web pages HTML / CSS 1. Generation Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

93. 3 Generations of Web Documents75 interactive web pages static web pages JavaScript / Applets Data Base Access HTML / CSS Template-based Generation dynamische web pages 1. Generation 2. Generation Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

94. 3 Generations of Web Documents75 interactive virtual web pages web pages static Netbots web pages JavaScript / Applets Information Extraction Presentation Planning Data Base Access HTML / CSS User Models Template-based Machine Learning Generation Online Layout dynamische adaptive web pages web pages 1. Generation 2. Generation 3. Generation Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

95. 76 Toolbox for the Semantic Web • Standardized languages to express semantics of information content in the Web (XML/XSD, RDF(S), OWL, RIF) • Tools to use semantic information in the Web (RDFa, GRDDL, ...) • Various ﬁelds of computer science: • artiﬁcial intelligence • linguistics • computer architecture • cryptography • software engineering • data bases • systems theory • theoretical computer science • computer networks Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

97. Next Lecture...78 URI/URL - Designator and Designated Brushup your XML and XML Schema... Resource Description Framework Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

98. Semantic Web Technologies Bibliography79 • P. Hitzler, S. Roschke, Y. Sure: Semantic Web Grundlagen, Springer, 2007. • P. Hitzler, M. Krötzsch, S. Rudolph: Foundations of Semantic Web Technologies, CRC Press, 2009. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

99. Semantic Web Technologies Bibliography80 • T. Heath, Ch. Bitzer Linked Data - Evolving the Web into a Global Data Space, Morgan & Claypool, 2011. Semantic Web Technologies , Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12

100. Semantic Web Technologies Further Reading81 □Blog http://semweb2013.blogspot.com/ □Webseite http://www.hpi.uni-potsdam.de/studium/ lehrangebot/itse/veranstaltung/ semantic_web_technologien-3.html □bibsonomy - Bookmarks http://www.bibsonomy.org/user/lysander07/ swt1213_01 Lecture Semantic Web Technologies, Dr. Harald Sack, Hasso-Plattner-Institut, Universität PotsdamDonnerstag, 18. Oktober 12