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Context sensitivity for networked ontologies

Context sensitivity for networked ontologies. Igor Mozeti č , Marko Grobelnik, Damjan Bojad žijev Jozef Stefan Institute Slovenia. text _ 1. text. expl( con text). text. text. con text. explicit. implicit. global. local. I’m here. who, where. c on text _ 1. +. Overview.

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Context sensitivity for networked ontologies

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  1. Context sensitivity for networked ontologies Igor Mozetič, Marko Grobelnik, Damjan Bojadžijev Jozef Stefan Institute Slovenia

  2. text_1 text expl(context) text text context explicit implicit global local I’m here who, where context_1 + JSI

  3. Overview • Formalizing context • Cyc • Semantic Web • C-OWL • Probabilistic approaches • JSI related work JSI

  4. McCarthy [1993] • AI: modelling of context and use in automated reasoning • implicit -> explicit • ist( context, proposition ) • context = collection of assumptions (generalization of, partially known) • entering and exiting, nesting, lifting, transcending, … JSI

  5. Cyc [Lenat, Guha] • Cyc KB = set of microtheories(Mt) • Microtheory = set of axioms • shared assumptions, topic • internally consistent • localized (more efficient) reasoning • preconditions = context in which Mt is applicable JSI

  6. Cyc (example) ist( NaiveStateChangeMt, isa( ?X, Freezing ) & outputsCreated( ?X, ?Obj ) => stateOfMatter( ?Obj, SolidStateMatter )) NaiveStateChangeMt domainAssumptions: forAll ?U isa( ?U, StateOfMatterChangeEvent ) => isa( ?U, CreationOrDestructionEvent ) JSI

  7. Context for Semantic Web [Guha et al] • Aggregation from different sources. Issues: • class differences • property type differences • point of view • implicit time • approximations JSI

  8. C-OWL [Giunchiglia et al]:Contextualizing ontologies JSI

  9. OWL: Global semantics for multiple (networked) ontologies shared model JSI

  10. OWL: Global semantics for multiple (networked) ontologies shared model import JSI

  11. C-OWL: Local model semantics local models JSI

  12. C-OWL: Mappings context context contextualized ontology JSI

  13. C-OWL ontology is a pair: • OWL ontology (target): • concepts • individuals • roles • mappings (bridge rules): •  equivalence •  onto •  into •  compatible •  incompatible JSI

  14. C-OWL example • OWL ontology (target) + mappings (bridge rules) JSI

  15. C-OWL of any use? • Import ontology vs. define context mappings? (diversity as defect vs. feature) • Semantic Web = Web of Semantic links ? (context mappings) • Discovering context mappings = core issue in building Semantic Web ? JSI

  16. JSI related work • Parametric temporal ontology • Simultaneous ontologies • User profiling • Implicit document context (links) JSI

  17. Temporal ontology • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) starts finishes day(mon) meets meets day(sun) JSI

  18. Temporal ontology • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes day(mon) meets meets day(sun) JSI

  19. Temporal ontology • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes day(mon) meets meets day(sun) day(now-1) meets day(now+1) meets day(now) JSI

  20. Temporal reasoning • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes day(mon) meets meets day(sun) ? equals day(now-1) meets day(now+1) meets day(now) JSI

  21. Temporal reasoning • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes starts day(mon) meets meets day(sun) day(mon) equals day(now-1) meets day(now+1) meets day(now) JSI

  22. Temporal reasoning • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes starts day(mon) meets meets day(sun) meets day(mon) equals day(now-1) meets day(now+1) meets day(now) JSI

  23. Temporal reasoning • Temporal algebra [Allen]: • event = temporal interval • relations: before, meets, starts, finishes, … week(now) meets week(now+1) starts finishes starts day(mon) meets meets day(sun) meets day(mon) equals equals day(now-1) meets day(now+1) meets day(now) JSI

  24. Parameterized temporal ontology • Parameters: • now • order of magnitude • past - future now = ? day week month year decade context now-1 now now+1 now+2 JSI

  25. earthquake tsunami tsunami tsunami tsunami News analysis News stream: the same? yet another one? JSI

  26. A temporal model: Tsunami Search & Rescue Rebuilding Earthquake ~days ~months ~minutes Tsunami ~hours E T S&R 25.dec 26.dec 27.dec 28.dec 29.dec 30.dec 31.dec 1.jan 2.jan 3.jan JSI

  27. earthquake tsunami tsunami tsunami tsunami News analysis: Temporal model = Context News stream: provides context for subsequent events model of tsunami JSI

  28. Summary • Parameterized ontology • Context determines parameters • when? • how long? • order of magnitude • Temporal model • selected by events • provides context JSI

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