Topic Maps and the Semantic Web

1. Topic Maps and theSemantic Web www.ontopedia.net

2. Semantic Web – The “Layer Cake” Tim Berners-Lee Keynote Speech in 2005 www.ontopedia.net

3. How the two families stack up OWL TMCL RDF Schema SPRQL TMQL QUERY Topic Maps ORG SYNTAX MODEL REASONING ORG SYNTAX MODEL CONSTRAINTS RDF XML XTM LTM CTM RDF/A RDF/XML N3 ISOSeamless Knowledge W3CSemantic Web

4. Topic Maps and the Semantic Web • Some people think RDF/OWL andTopic Maps are competitors • I do not think this is not true • I think they complement each other • The Semantic Web gets muchmore publicity • W3C can bask in the glamour of the Web • RDF and OWL appealed immediately to academics • But why do people think they compete? • RDF/OWL and Topic Maps have a number of similarities • They stem from rival organizations (W3C and ISO) • There are a few bigots • Most people do not understand the difference... RDF/OWL Topic Maps Romeo and Juliet www.ontopedia.net

5. The are superficial similarities • Both “extend” XML into the realm of semantics • Both allow assertions to be made about things in the real world • Both define abstract, associative (graph-based) models • Both have URI-based models of identity • Both allow forms of inferencing or reasoning • Both have XML-based interchange syntaxes • Both have constraint languages and query languages But they are also different in some crucial respects... www.ontopedia.net

6. But the differences are significant • Different roots • Topic Maps has its roots in traditional finding aids (indexes, thesauri, etc.) • RDF/OWL has its roots in document metadata and formal logic • Different levels of semantics… • RDF is more low level • Topic Maps has more higher-level semantics • Different models • Identity, scope, association roles, n-ary relationships, variant names, … • Different goals • RDF: An artificially intelligent web for software agents • Topic Maps: Findability and knowledge integration for humans www.ontopedia.net

7. The Most Crucial Differences • RDF/OWL is for machines; • Topic Maps is for humans. • RDF/OWL is optimized for inferencing; • Topic Maps is optimized for findability. • RDF/OWL is based on formal logic; • Topic Maps is not based on formal logic. • RDF/OWL is to mathematics as Topic Maps is to language. • RDF/OWL is to Aristotle as Topic Maps is to Wittgenstein. www.ontopedia.net

8. A H A H T E C T What is this supposed to be? • Is it an H or an A? • The moral is: Fuzziness is a fact. • Humans can handle it; machines can’t. www.ontopedia.net

9. Different capabilities • RDF/OWL, to support logic-based inferencing,cannot allow fuzziness • Topic Maps, because it is for humans,has to support fuzziness • OWL ontologies tend to be very stringent and complex • Topic Maps ontologies tend to be simple and less formal • OWL has properties for things that Topic Maps doesn’t need • Some Topic Maps features would be too complex for OWL • In short, they are optimized for different purposes... www.ontopedia.net

10. RDF or Topic Maps? • Do you simply want to encode document metadata? • RDF is ideal and you won’t need OWL • Do you want to achieve subject-based classification of content? • Topic Maps provides the best combination of flexibility and user-friendliness • Do you want both metadata and subject-based classification? • Go straight for Topic Maps because it also supports metadata • Do you want to develop agent-based applications? • Use RDF/OWL ... but if you already have Topic Maps, you’re half way there • Most importantly, whatever you choose, you can always move your data between RDF and Topic Maps, thanks to the RDFTM work… • RDF is more low-level; oriented towards machines • Topic Maps is more high-level; oriented towards humans • OWL is oriented towards artificial intelligence www.ontopedia.net

11. RDFTM: Data interoperability • RDF/Topic Maps Interoperability Task Force • A task force within the Semantic Web Best Practicesand Deployment Working Group • Chartered to deliver two documents: • Survey of Existing Interoperability Proposals • Guidlines for RDF/Topic Maps Interoperability • Survey published in February 2006 • http://www.w3.org/TR/rdftm-survey/ • Draft guidelines published in June 2006 • http://www.w3.org/2001/sw/BestPractices/RDFTM/guidelines-20060630.html • The task force is now disbanded and the work will be finalized by ISO www.ontopedia.net

12. Topic Maps andHypertext www.ontopedia.net

13. Bill Atkinson 1987 HyperCard Doug Engelbart 1962 Augmenting Human Intellect NLS / AUGMENT Vannevar Bush 1945 As We May Think Memex Tim Berners-Lee 1989 Information Management: A Proposal World Wide Web Ted Nelson 1965 “Hypertext” Xanadu Vannevar Bush and Hypertext www.ontopedia.net

14. “As We May Think” • Concerned with the problem of finding information • Existing technology hopelessly out of date: • The amount of information is being “expanded at a prodigious rate”, but the means we use to find it is “the same as was used in the days of square-rigged ships” • The solution is to get away from hierarchical systems of organization and adopt new techniques that reflect how the brain works Vannevar Bush 1945 As We May Think MEMEX www.ontopedia.net

15. Associative thinking “The human mind … operates by association. With one item in its grasp, it snaps instantly to the next that is suggested by the association of thoughts, in accordance with some intricate web of trails carried by the cells of the brain… The speed of action, the intricacy of trails, the detail of mental pictures, is awe-inspiring beyond all else in nature.”Vannevar Bush: As We May Think (1945) www.ontopedia.net

16. A “sort of mechanized private file and library” Memex (memory extender) www.ontopedia.net

17. Memex (memory extender) • Consists of a desk containing • a very large set of documents stored on microfilm • screens on which those documents are projected • a device for photographing new documents • a mechanism for retrieving documents at the push of a button • the ability to create links between documents • the ability to build trails through documents, add comments to documents, insert new documents, etc. • Note how everything revolves around documents • Consists of a desk containing • a very large set of documents stored on microfilm • screens on which those documents are projected • a device for photographing new documents • a mechanism for retrieving documents at the push of a button • the ability to create links between documents • the ability to build trails through documents, add comments to documents, insert new documents, etc. • Note how everything revolves around documents www.ontopedia.net

18. Is this how you think? • Is your head full of little documents all hyperlinked together? • I doubt it ! • Mine certainly isn’t ! • We don’t think in terms of hyperlinked documents; we think in terms of concepts, and associations between concepts ? www.ontopedia.net

19. How we really think WWW • Documents are about subjects • Those subjects exist as concepts in our brains • They are connected by a network of associations • This is how we store knowledge • Documents are just a representation of some part of that knowledge Berners-Lee Engelbart Bush Hypertext As We May Think AUGMENT MEMEX Xanadu Nelson NLS www.ontopedia.net

20. Bush – right and wrong • Vannevar Bush was right that people think associatively • He was right that organizing information in this way would make it easier to find • But he was wrong in adopting a document-centric approach to the problem • His basic idea – organize information “as we may way think” – was a great inspiration to Engelbart, Nelson, Atkinson, and Berners-Lee www.ontopedia.net

21. Barking up the wrong tree • But the Memex sent them all off in the wrong direction • Hypertext has been barking up the wrong tree ever since • And the Web, magnificent as it is, has made things “worse” www.ontopedia.net

22. “As We May Think” (63 years on) • Concerned with the problem of finding information • Existing technology hopelessly out of date: • The amount of information is being “expanded at a prodigious rate”, but the means we use to find it is “the same as was used in the days of square-rigged ships” • The solution is still to get away from hierarchical systems of organization and adopt new techniques that reflect how the brain works • That solution has to be subject-centric, not document-centric like the Web Vannevar Bush 1945 As We May Think MEMEX card catalogs www.ontopedia.net

23. WWW Berners-Lee Engelbart Bush composed by Hypertext As We May Think AUGMENT composed by MEMEX Tosca Xanadu Nelson Puccini MadameButterfly born in NLS Lucca knowledge layer information layer Which brings us to Topic Maps • What’s special about it? • #1 The TAO* model corresponds to how people think * Topics + Associations + Occurrences www.ontopedia.net

24. Subject-centric computing– a broader perspective www.ontopedia.net

25. Topic Maps as a paradigm shift • Topic Maps started out as a way to merge indexes • It turned into a knowledge representation formalism • But its significance is far greater • Now the flag-bearer for subject-centric computing • A paradigm shift in how we use computers • Cf. object-oriented programming... • ...and Copernicus www.ontopedia.net

26. Object-oriented programming • Response to 1960’s software crisis • Computer programs more and more complex • Difficult to maintain software quality • Code simulates the world (as perceived by a human) • Objects represent real-world concepts (cf. topics) • They are grouped into classes (cf. topic types) • Data structures capture relationships between objects(cf. associations) • Represented a paradigm shift in programming • OO languages now near universal (Java, C#, Ruby, Python, ...) www.ontopedia.net

27. Sun Earth Earth Sun The heliocentric revolution • For 1,000s of years people thought that the sun revolved around the earth • In 1543 Copernicus changed all that • His heliocentric theory turned our understanding of the universe inside out. • This was another paradigm shift • (Actually some Greek, Indian and Muslim scholars knew better, but the view of Aristotle, Ptolemy and the Christian Church was dominant) www.ontopedia.net

28. Subject-centric computing • Today we face a similar situation in computing and information management • Computers are at the centre of our information universe • Applications and documents revolve around them • The subjects we’re really interested in are nowhere to be seen • Or at least, nowhere to be found www.ontopedia.net

29. Computing “as we may think” • This is wrong, because it does not reflect how humans think • Humans think in terms of subjects, concepts, ideas • We must put subjects at the centre, because that’s what we’re really interested in • This is the essence ofsubject-centric computing • It really is a paradigm shift – • Topic Maps is showing the way www.ontopedia.net

30. www.ontopedia.net

31. TM2008 Topic page Emails Documents Web pages Copy PSI Ψ gambia K185 opera topic maps OOXML LING 2110 tm2008 rana INF 2820 janacek bantu semantics www.ontopedia.net keynote bayreuth håkon

32. Subject-centric file system • The file system is a hierarchy and that’s a pain • Trees aren’t expressive enough • WinFS looked like it might change all that • New data storage and management system announced in 2003 • Didn’t make it into Vista. Seems to have disappeared • Let the new file system be a topic map! • “Folders” are topics with global identifiers • User-defined metadata on “folders” (internal occurrences) • External occurrences • Related through navigable, typed associations www.ontopedia.net

33. Subject-centric operating system • Now that the file system is a topic map, why not go the whole hog? • Services to applications for assigning PSIs • NLP based help for (semi-automatically) categorizing documents • Ability to extract fragments from the system topic map • Peer-to-peer features for exchanging fragments with others • Facilities for context-based virtual merges under user control • ... www.ontopedia.net