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Identity

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Identity

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  1. Identity Steve Pepper pepper.steve@gmail.com Oslo University College, 2008-10-27 www.ontopedia.net

  2. Week 37 – 09-08 Introduction to Topic Maps – Part 1 Week 38 – 09-15 Creating a topic map Week 39 – 09-22 Introduction to Topic Maps – Part 2 Week 42 – 10-13 Modelling issues (LTM) Week 43 – 10-20 Ontology-driven editing Week 44 – 10-27 Identity Week 48 – 11-24 (Semantic Web) Move to end of Week 47??? Terminology: Topic Maps: The technology and the standard topic maps: The artefacts (documents) we create Course agenda www.ontopedia.net

  3. Today’s agenda • Identity • Subject identifiers and subject descriptors • (subject locators) • (item identifiers) • Discussion of group projects www.ontopedia.net

  4. Identity: The all-important issue • What makes merging possible? • NOT the use of names, which are notoriously unreliable • Names are not unambiguous (the homonym problem) • Many topics have multiple names (the synonym problem) • Achievement of the collocation objective • Only possible through the use of unique global identifiers • The issue of identification of subjects is therefore crucial • If subjects have unique identifiers, people can be free to use whatever names they like – and machines can still aggregate information www.ontopedia.net

  5. A subject in the real world A topic in the computer domain T Subjects and Topics • Topics are surrogates, or “proxies” (inside the computer) for the ineffable subjects that you want to talk about, such as Puccini, love, these slides, or the second law of thermodynamics www.ontopedia.net

  6. Tosca Lucca MadameButterfly Puccini The identity of subjects • Topics exist in order to allow us to talk about subjects • The relationship between the two is sometimes called intentionality • We need to know exactly which subject a topic represents • That is, we need to establish its subject identity • The collocation objective depends on knowing when applications are talking about the same thing www.ontopedia.net

  7. Life, the Universe and Everything subject Giacomo Puccini, Italian composer, b. Lucca 22nd Dec 1858, d. Brussels, 29th Nov 1924. Best known for his operas, of whichTosca is the most . . . The Computer Domain subject identifier subject descriptor http://psi.ontopedia.net/Puccini Puccini topic The Topic Map Domain Subject identifiers • The identity of most subjects can only be established indirectly • An information resource can provide an indication of the subject’s identity to a human • Such a resource is called a subject descriptor • A subject descriptor has an address,even though the subject it indicatesdoes not • Computers can use the address of thesubject descriptor to establish identity • Such addresses are calledsubject identifiers • Subject descriptors and subject identifiers are the two sides ofthe human-computer dichotomy www.ontopedia.net

  8. Published Subjects • In order for identifiers to be reused, they must made publicly available • A subject identifier that has been made available for use outside one particular application is called a published subject identifier (PSI) • Its descriptor is called a published subject descriptor (PSD) • Anyone can publish PSI sets • Adoption of PSI sets will be an evolutionary process based on trust • It will lead to greater and greater interoperability – between topic map applications, between Topic Maps and RDF, and across information and knowledge management in general • Check out http://psi.ontopedia.net (under development) www.ontopedia.net

  9. PSIs for machines and humans www.ontopedia.net

  10. Advice on subject identifiers • Always use them for your typing topics • Makes your ontology more portable • The more serious your application, the more extensively you should use them for instances • Merging with other topic maps will not be successful without identifiers • LTM code for subject identifiers • See previous lecture and opera.ltm • Example: • [composer = "Composer" @"http://psi.ontopedia.net/Composer"] www.ontopedia.net

  11. Identifiers • Use an identifier for every typing topic • Use the prefix http://psi.ontopedia.net/ • Reuse existing identifiers wherever possible • Choice of suffix for topic types and role types: • A short name, preferably the same as Wikipedia uses • Start with a capital letter; accented letters are OK • Replace spaces by underscores • Examples: Composer, Fairy_tale, Work_of_art, Place • For association types, occurrence types and name types: • Use a verb (association types) or a noun (occurrence and name types) • Start with a lower-case letter (to indicate a property) • Examples: composed_by, date_of_birth, given_name • Check Norwegian Opera for examples • Do not use the Italian Opera Topic Map – its conventions are outdated www.ontopedia.net

  12. More tips for your ontology • Provide a description for every topic type: • Give a short definition • Comments (if necessary) on the way in which the type is (intended to be) used in the topic map • http://www.ontopedia.net/omnigator • For examples of recommended best practice • Refer to the Norwegian Opera Topic Map • See http://www.ontopedia.net/NorwegianOpera/ontology.jsp • Use the Omnigator version listed under Topic Maps at www.ontopedia.net • Download it to your machine using the Export plug-in • This query lists all subject identifiers for typing topics: select $TYPE, $SID from { instance-of($T, $TYPE) | type($T, $TYPE) }, subject-identifier($TYPE, $SID) order by $TYPE? www.ontopedia.net

  13. Role types select $AT, $RT1, $RT2 from association-role( $A, $R1 ), association-role( $A, $R2 ), type($A, $AT), type($R1, $RT1), type($R2, $RT2), $R1 /= $R2 order by $AT? www.ontopedia.net

  14. Project Groups African Nations Cup 2008 African Writers DILL Program HIO Databases Norwegian Feature Films The Nobel Prize Topic Maps Bibliography Topic Maps Tools Whisky www.ontopedia.net

  15. Phuong, Nga, Szu-PingHIO Databases Andrea, Juan-Daniel, Mehrnoosh, SaraDILL Program Pussadee, Roriana, WachirapornNobel Prizes Nickson, Florence, MonicaTopic Maps Bibliography Alice, Barulaganye, EstherAfrican Writers Muluken, YibeltalTopic Maps Tools Anja, Clara, Kanita, TrudeNorwegian Feature Films Isaac, WilfredAfrican Nations Cup ChristianWhisky Groups www.ontopedia.net

  16. The assignment is to create a topic map using Ontopoly.It will be judged on the following criteria: Accuracy of modelling type hierarchy other hierarchies appropriate role types appropriate naming Consistency of names assertions Appropriate size: Topics: 250–1,000 TTs: 10–35 Associations: 500–2,500 ATs: 10–45 Occurrences: 500–2,500 OTs: 10–25 Degree of interest sufficient number of topics rich set of interconnections large number of interesting occurrences of different types Documentation every typing topic should have a PSI and a description Semester Assignment www.ontopedia.net

  17. Statistics from 2007 www.ontopedia.net

  18. African Nations Cup 2008 www.ontopedia.net

  19. African Writers www.ontopedia.net

  20. DILL Program www.ontopedia.net

  21. HIO Databases www.ontopedia.net

  22. Norwegian Feature Films www.ontopedia.net

  23. The Nobel Prize www.ontopedia.net

  24. Topic Maps Bibliography www.ontopedia.net

  25. Topic Maps Tools www.ontopedia.net

  26. Whisky www.ontopedia.net

  27. Home assignment • Finalize the ontology • Document it by providing a short description of each typing topic • Send me the XTM file by email before November 3 • Populate the topic map • Make a note of any issues that arise for discussion in class on November 10 • Prepare a presentation • Thesis seminar: November 28 www.ontopedia.net

  28. Next Topic Maps lecture • Thursday November 20 (09.30) • Same place • Agenda • Topic Maps and the Semantic Web • Project Review www.ontopedia.net