the knowledge cartography a new approach to reasoning over description logics ontologies n.
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The Knowledge Cartography – A New Approach to Reasoning over Description Logics Ontologies

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  1. The Knowledge Cartography –A New Approach to Reasoning over Description Logics Ontologies Krzysztof Goczyła, Teresa Grabowska, Wojciech Waloszek, Michał Zawadzki January 21-27, 2006, Měřín, Czech Republic

  2. PIPS Upper layers Knowledge KMS KaSeA KaSeA RDB RDB Data Internet

  3. Motivations • PIPS manages knowledge about: • ilnesses, • drugs, • alergies, • diets, • … • Required data are gathered from many internet sources; the number of information is very large.

  4. Knowledge Cartography • Main assumptions: • Terminology is updated so rarely that it might be considered constant in time. • A knowledge base is queried much more often than updated (new individual assertions). • A knowledge base should be able to hold and efficiently process information about large numbers of individuals.

  5. Knowledge Cartography • Developed to: • simplify reasoning on numerous objects (individuals), • simplify storage of inferred results concerning numerous individuals. • Processes ontological information in accordance to Description Logics and Semantic Web standard.

  6. Terminology – an example • Terminology is described by a set of statements - axioms. • Suppose, we want to describe the world of people and their pets: • There are no other creatures except People, Dogs and Cats, • People, Dogs and Cats are disjoint, • Dogs and Cats are CreaturesHavingTails, • People and Cats can be CreaturesTakingCareOfHygiene.

  7. Map of concepts There are no other creatures except People, Dogs and Cats People  Dogs  Cats 

  8. Map of concepts People, Dogs and Cats are disjoint People  Dogs  People  Cats  Cats  Dogs 

  9. Map of concepts Dogs and Cats are CreaturesHavingTails CreaturesHavingTails  Dogs  Cats

  10. Map of concepts People and Cats can be CreaturesTakingCareOfHygiene CreaturesTakingCareOfHygiene  People CreaturesTakingCareOfHygiene  Cats

  11. Map of concepts

  12. 1 2 3 5 4 Map of concepts – signatures 11000 01000  00001 00010  00111 11111 

  13. Terminological queries Must every person take care of hygenie? 11000 NO 10011 Is a creature without a tail a person? 11000 YES 11000 Is a creature which have a tail and takes care of hygenie a cat? 00100  YES 00110

  14. Individuals’ signatures • Individuals’ signatures describe what we know and what we do not know about individuals Source 1: Fred has a tail 00111 Is Fred a person? 00111 NO 11000 Is Fred a dog? 00111 MAYBE 00001

  15. We know something more… Source 2: Fred takes care of hygenie 00111 01100 , 00100 Is Fred a dog? 00100 NO 00001 Is Fred a cat? 00100 YES 00110

  16. Restrictions • Role constructors in the form of R.C and R.C are treated as concepts • Such constructors must be explicitly defined in ontology.

  17. Deployment in PIPS • Cartographic approach has been succesfully deployed in the first release of PIPS system, • Allowed for achieving short (<1 s) response times for queries in knowledge bases with very large (>10000) number of individuals (sublinear scalability).

  18. Future work • Compression of signatures and hierarchical signatures, • Introducing signatures not only for concepts but also for roles (relations) between individuals. • Extending expresiveness of KaSeA in order to support complex queries (cardinality constraints, functional, symetric and transitive roles),

  19. Thank you!