1. SWAP-07 Ontology Engineering with OntoClean Chris Welty IBM Watson Research Center

2. SWAP-07 2 Acknowledgements People Nicola Guarino Cladio Masolo Aldo Gangemi Alessandro Oltramari Bill Andersen Organizations IBM Research Vassar College, USA LADSEB-CNR, Padova CNR Cognitive Science Institute, Trento OntologyWorks, Inc.

3. SWAP-07 3 Which one is better? T-Series ThinkPad T Series ThinkPad Model Thinkpad model

4. SWAP-07 4 Which one is better? Computer has-part Memory Disk Drive Computer Part Memory Part Disk Part Computer Part Disk DriveMemory Computer has-part Due to: Guizzardi, et al, 2004.

5. SWAP-07 5 Formal Ontology of Relations Subsumption Instantiation Part/Whole Constitution Spatial (Cohn) Temporal (Allen)

6. SWAP-07 6 Subsumption The most pervasive relationship in ontologies –Influence of taxonomies and OO AKA: Is-a, a-kind-of, specialization-of, subclass (Brachman, 1983) –“horse is a mammal” Capitalizes on general knowledge –Helps deal with complexity, structure –Reduces requirement to acquire and represent redundant specifics What does it mean? □  x  (x)   (x) Every instance of the subclass is necessarily an instance of the superclass

7. SWAP-07 7 Overloading Subsumption Common modeling pitfalls Instantiation Constitution Composition Disjunction Polysemy Temporality Spatial/Containment

8. SWAP-07 8 Instantiation Pitfall T21 My ThinkPad (s# xx123) ThinkPad Model Ooops… Question: What ThinkPad models do you sell? Answer should NOT include My ThinkPad -- nor yours. Does this ontology mean that My ThinkPad is a ThinkPad Model?

9. SWAP-07 9 Instantiation T Series My ThinkPad (s# xx123) ThinkPad ModelNotebook Computer model T 21

10. SWAP-07 10 Composition Pitfall Memory Disk Drive Computer Question: What Computers do you sell? Answer should NOT include Disk Drives or Memory. Micro Drive

11. SWAP-07 11 Composition Memory Disk Drive Computer Micro Drive part-of

12. SWAP-07 12 Disjunction Pitfall Memory Disk Drive Computer Micro Drive has-part Computer Part Flashcard-110 Camera-15 has-part Unintended model: flashcard-110 is a computer-part

13. SWAP-07 13 Disjunction Computer has-part Disk Drive  Memory  …

14. SWAP-07 14 Polysemy Pitfall ( Mikrokosmos) Abstract Entity Physical Object Book Question: How many books do you have on Hemingway? Answer: 5,000 …..

15. SWAP-07 15 Polysemy (WordNet) Abstract Entity Physical Object Book Sense 1 Book Sense 2 ….. Biography of Hemingway

16. SWAP-07 16 Constitution Pitfall (WordNet) Amount of Matter Physical Object Entity Computer Clay Metal Question: What types of matter will conduct electricity? Answer should NOT include computers.

17. SWAP-07 17 Constitution Amount of Matter Physical Object Entity Computer ClayMetal constituted

18. SWAP-07 18 Temporality Pitfall (Wikipedia) 1963 1964 1960s Chris

19. SWAP-07 19 Temporality Pitfall (Wikipedia) 1963 births 1964 births 1960s births Chris

20. SWAP-07 20 Temporality 1963 1964 1960s Chris contains bornIn Person Decade Year

21. SWAP-07 21 Spatial/Containment Pitfall (OWL Guide) Alsace Region Loire Region French Region

22. SWAP-07 22 Spatial/Containment Alsace Loire France Region Country contains

23. SWAP-07 23 Its about the instances For every class, think about what an instance of it is –What is an instance of “Loire Region”? Classes do not describe their subclasses –“Regions by Country” is a class of classes Criteria for individuation must remain constant within a taxonomy –Instance of a class is also an instance of every superclass Thus “Chris” is not an instance of “1963 births” –Explore the “boundary conditions” E.g. Changes in existence, distinctions with similar classes “Leaf Nodes” of a hierarchy have no special significance –Don’t switch to instances

24. SWAP-07 24 Common Pitfalls Composition (part of) –Arm subclass body Constitution –Statue subclass marble Disjunction –(class Car partial (all hasPart CarPart) –(Engine subclass CarPart) –(Tire subclass CarPart) Spatial –NewYork subclass US Polysemy –Book subClass PhysicalObject –Book subClass ConceptualCreation Arbitrary organizational nodes –FictionalBookbyLatinAmericanAuthor subClass FictionalBook Instance –PinotNoir instanceof Grape Temporality –YoungElvis instanceOf Elvis

25. SWAP-07 25 The linguistic tests If P subclass Q, you should be able to say “P is a kind of Q” If a instanceOf P, you should be able to say, “a is a P” If a instanceof P subClassOf Q, you should be able to say “a is a Q” For every instance, there should be a class it is (rigidly) an instance of that is its natural label You should not find it natural to say, if P subclassOf Q, “P has Q”, “P might be Q”, “P was Q”, “P is in Q”, “P is part of Q”

26. SWAP-07 26 What’s in a name Don’t argue about what specific terms mean –Common software architecture argument: “What is a bridge?” Try and find the distinctions that matter –Assign them labels later Avoid “ish” “-thing” & “other-” classes –Find good names that will avoid meaning creep –Other- classes create a maintenance nightmare Classes describe their instances –Remember the linguistic tests The superclass is not part of the name –So don’t assume it is (e.g. Best_Practices subClassOf Document)