Towards a Distributed Reasoning within Multiple Ontologies

1. 2K* symposium Towards a Distributed Reasoningwithin Multiple Ontologies by Andrei Tamilin UniTN Luciano Serafini IRST & September 6-9, 2004 Madonna di Campiglio

2. Talk Outline • Preamble: Ambitions and Realities of SW. • Motivation: Why and how to distribute? • Formal framework: DDL in a nutshell • Reasoning in DDL • DRAGO – reason-able implementation 2K* - 2004: Towards a Distributed Reasoning - p.2

3. Preamble: The distant 2001 … • The Semantic Web. By Tim Berners-Lee, James Hendler and Ora Lassila. A new form of Web content that is meaningful to computers will unleash a revolution of new possibilities. • Original driver: Automation • Means: “Machine-friendly” web metadata • Goal: Application interoperability • Means: Ontology 2K* - 2004: Towards a Distributed Reasoning - p.3

4. Preamble: Three years later … • SW equipment: • Languages: RDF, RDFS, DAML, OIL, DAML-OIL, OWL • Theory: Description Logics (DL) • Reasoning support: FaCT, Racer, Pellet, etc. • Management: plenty of tools … • It’s time to make the SW a reality: • 2004-2006, KnowledgeWeb project 2K* - 2004: Towards a Distributed Reasoning - p.4

5. Preamble: The realities • Ontology proliferation: • Galaxy of ontologies • Galaxy distinguishing features: • Multiplicity • Heterogeneity • Making ontologies interoperate: • Means: Semantic mappings • Enough? • No • Reasoning support is required! 2K* - 2004: Towards a Distributed Reasoning - p.5

6. Preamble: The realities • Cosmopolitism of current reasoning methodology: • Global ontology • Reason in global ontology • Arising questions: • Scalability? • Reasoning specificity? • Privacy? Autonomy? 2K* - 2004: Towards a Distributed Reasoning - p.6

7. Motivation: Towards a distribution • Alternative approach: • Local reasoning • Suitable combination • Requirements: • Formal framework • Reasoning algorithm • The reason-able system implementation 2K* - 2004: Towards a Distributed Reasoning - p.7

8. T-box A-box T-box A-box M-box M-box M-box M-box T-box A-box T-box A-box Formal framework: DDL in a nutshell • Distributed Description Logics (DDL) • Captures the case of multiple ontologies pairwise linked by semantic mappings • Ontologies: • DL knowledge bases (T-box and A-box) • Mappings: • Bridge rules (M-box) 2K* - 2004: Towards a Distributed Reasoning - p.8

9. A Galaxy Neptune: B D B C A Earth C D Reasoning in DDL • Similarly to DL: • Core reasoning task in DDL –concept subsumption • Difference from DL: • Scope – Galaxy • Mappings matter • Subsumption in DDL – a global subsumption 2K* - 2004: Towards a Distributed Reasoning - p.9

10. Local Tableau Local Tableau Local Tableau Local Tableau Local Tableau Propagation Propagation Propagation Propagation Propagation Distributed reasoning algorithm Cycle is detected Reasoning is finished 2K* - 2004: Towards a Distributed Reasoning - p.10

11. DRAGO Manager 2 DRAGO Manager 1 DRAGO Manager 3 DRAGODistributed Reasoning Architecture for Galaxy of Ontologies 2K* - 2004: Towards a Distributed Reasoning - p.11

12. <owl:Class rdf:ID="Polite_Drago"> <rdfs:subClassOf> <owl:Restriction> <owl:onProperty> <owl:ObjectPropertyrdf:ID=“tells_after_presentation"/> </owl:onProperty> <owl:someValuesFrom> <owl:Class> <owl:unionOf rdf:parseType="Collection"> <owl:Class rdf:about=“&Luciano;#Grazie"/> <owl:Class rdf:about=“&Andrei;#Dziakuj"/> </owl:unionOf> </owl:Class> </owl:someValuesFrom> </owl:Restriction> Grazie Dziakuj 2K* - 2004: Towards a Distributed Reasoning - p.12

13. Questions? 2K* - 2004: Towards a Distributed Reasoning - p.13

14. Acknowledgements • We thank Kevin Palivec for the beautiful picture of DRAGO1 he painted. We promise that it will be used by us for the research purposes only. 1http://lair2000.net/Dragon_Pictures/Dragon_Pictures.html 2K* - 2004: Towards a Distributed Reasoning - p.14