1. 30.10.06 Krzysztof Janowicz SIM-DL -Towards a Semantic Similarity Measurement Theory for the Description Logic ALCNR in Geographic Information Retrieval Krzysztof Janowicz Institute for Geoinformatics; University of Münster

2. Krzysztof JanowiczSIM-DL (for ALCNR) 2 Outline Motivation: Yet Another Similarity Theory? Similarity & Subsumption based IR Matching Scenario SIM-DL Framework Human Subject Testing Results, Conclusions & Outlook

3. Krzysztof JanowiczSIM-DL (for ALCNR) 3 Yet Another Similarity Theory? Available ontologies (DL!) Available theories Measured between (re)representation! http://flickr.com/photos/genista/25390358/

4. Krzysztof JanowiczSIM-DL (for ALCNR) 4 Similarity & Subsumption based Retrieval

5. Krzysztof JanowiczSIM-DL (for ALCNR) 5 Similarity vs. Subsumption Subsumption-based Retrieval (+) Results fit user’s requirements (subconcepts!) (-) Too generic / too specific result set (-) Artificial search concept Similarity-based Retrieval (+) Search concept = searched concept (-) Results not necessarily fit user’s requirements

6. Krzysztof JanowiczSIM-DL (for ALCNR) 6 Matching-Scenario Accommodation web portal External services (SOA) Use shared base vocabulary Local interface and terminology Hotel, Houseboat, Youth Hostel, Botel,….  Task: Integrate Amsterdam-Accommodation Service Where to put botels?

7. Krzysztof JanowiczSIM-DL (for ALCNR) 7 Houseboats, Hotel &Botel

8. Krzysztof JanowiczSIM-DL (for ALCNR) 8 Some Impressions Pictures received by email, taken from wikipedia and http://www.hotels.nl/amsterdam/botel/

9. Krzysztof JanowiczSIM-DL (for ALCNR) 9 SIM-DL: Representation (ALCNR)

10. Krzysztof JanowiczSIM-DL (for ALCNR) 10 SIM-DL: Framework 1.Specify search concept and context 2.Rephrase concepts to canonical NF 3.Generate alignment matrix 4.Apply sim-functions for selected combinations 5.Derive normalized overall similarity

11. Krzysztof JanowiczSIM-DL (for ALCNR) 11 SIM-DL: Search Concept & Context (-) Results not necessarily fit user’s requirements  Define Context C lcs ≡ Housing C s ≡ Botel

12. Krzysztof JanowiczSIM-DL (for ALCNR) 12 Rephrase Concepts to Canonical NF ALCNR Normal Form: + Rewriting rules (e.g.  R(  ) ≡ (≤ 0 R)) + Minimal set of descriptions (concepts)  Canonical Normal Form

13. Krzysztof JanowiczSIM-DL (for ALCNR) 13 Generate Alignment Matrix Cartesian Product C s  C t  CsiCsi CsjCsj CskCsk CtiCti N…… CtjCtj ……H CtkCtk …CO… CtlCtl ……… Hierarchies Neighborhoods Co-Occurrence H > N > CO

14. Krzysztof JanowiczSIM-DL (for ALCNR) 14 Apply Similarity-Functions (for selected combinations) Individual similarity functions for each DL language constructor:  {union, intersection, role-intersection, existential quantification, value restriction, cardinality} For Hierarchies, Neighborhoods, Co-Occurrence edge_distance max_distance

15. Krzysztof JanowiczSIM-DL (for ALCNR) 15 Amalgamated & Normalized Overall Similarity Union-Constructor:  Weighted sum of similarities on CNF union level  Weightings derived from A-Box, T-Box or A&T-Box Intersection-Constructor:  Sum of similarities on CNF intersection level  Normalization to [0,1]

16. Krzysztof JanowiczSIM-DL (for ALCNR) 16 Human Subject Testing: Roles & Fillers Auto. weighted average (>) Multiplicative approach (<) User input Disjoint from watercourse Meets river

17. Krzysztof JanowiczSIM-DL (for ALCNR) 17 Results, Conclusion & Outlook SIM-DL combines subsumption and similarity Adapts results from psychology & computer science  Cognitive Engineering ;-) Only basic model of Alignment and Context More Human Subject Tests needed More expressive DL Usability? Near ?

18. 30.10.06 Krzysztof Janowicz Questions? Thanks for your attention! Visit www.similarity-blog.de for related literature.www.similarity-blog.de From: http://www.jobblog.ch/sommer-250