Klaus M. Frei1 WordNet „An On-line Lexical Database“ (Miller, G. A.; Beckwith, R.; Fellbaum, Chr.; Gross, D.; Miller, K. 1993, title). Based on psycho-linguistic insights (ibd.) „Nouns in WordNet: A Lexical Inheritance System“ (Miller, G. A. 1993, title). „lexical resource“ (Guarino 1998, p. 12) WordNet synsets are „[...] more like a thesaurus“ (Buitelaar 1998, p. 223) „Synset: A synonym set; a set of words that are interchangeable in some context.“ (WordNet Glossary of Terms. Is WordNet an ontology? University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei2 WordNet „To be used as an ontology, however, some of WordNet’s lexical links need to be interpreted according to some formal semantics, (sic!) which tells us something about „the world“ and not (just) about the language. One of such links is the hyponym/hypernym relation, which corresponds in many cases to the usual subsumption (or IS-A) relation between concepts“ (Oltramari et al. 2002, p. 1 – own counting). University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei3 OntoClean „First of all, we do not intend this [i.e. OntoClean – KMF] as a can- didate for a “universal” standard ontology. Rather, we support the vision of a library of foundational ontologies, reflecting diffe- rent commitments and purposes“ (Oltramari et al. 2002, p. 3 – ita- lics orig, own counting). University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei4 OntoClean Ass.: „[...] [S]ubsumption [...] that is the basis of taxonomy is an extremely useful tool for imparting structure on an ontology. It is by far the most commonly used structuring primitive [...]“ (Guarino & Welty 2002, p. 63). Impl.: „[...] these metaproperties impose constraints on the sub- sumption relation, which can be used to check the ontological consistency of taxonomic links“ (ibd., p. 62 – emph KMF). „One of these constraints is that anti-rigid properties cannot subsume rigid properties“ (ibd.). University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei5 WordNet by OntoClean Confusion between concepts and individuals i.e. sortals vs. instances or IS-A vs. INSTANCE-OF E.g.: Territorial Dominion The look of WordNet 1.6 original University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei6 WordNet University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei7 OntoClean University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei8 WordNet original WordNet OntoClean WordNet original WordNet OntoClean University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei9 Apple in WordNet University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei10 WordNet University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei11 OntoClean University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei12 OntoClean Ass.: „[...] [S]ubsumption [...] that is the basis of taxonomy is an extremely useful tool for imparting structure on an ontology. It is by far the most commonly used structuring primitive [...]“ (Guarino & Welty 2002, p. 63). Impl.: „[...] these metaproperties impose constraints on the sub- sumption relation, which can be used to check the ontological consistency of taxonomic links“ (ibd., p. 62 – emph KMF). „One of these constraints is that anti-rigid properties cannot subsume rigid properties“ (ibd.). University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei13 WordNet University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002 KMF !

Klaus M. Frei14 University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002 Apple in WordNet Redundancies/Ambiguities

Klaus M. Frei15 WordNet University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002 Redundancy Ambiguity (resolved)

Klaus M. Frei16 OntoClean University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei17 Conclusion WordNet Psycho-linguistically motivated, implemented thesaurus May be used as an ontology – subsumption-based Hyponyms Hypernyms –only along with serious problems highly redundant huge inconsistencies Because of its ample and long- term generated database it is widespread. Besides: it is free. OntoClean Meta-Ontology –Conglomerate of principles –Examination tool for (existing) ontologies Purpose and Use –Get a well-formed ontology –Ontology and its entities/con- cepts/instances are: consistent coherent exclusively disjoint specific to a dominion exhaustive non-redundant, unambiguous and free of controversy Method –Labelling of each entity by meta- properties. This causes a well-for- med ontology by use of sub- sumption axioms. University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei18 References Buitelaar, P.: CoreLex: An Ontology of Systematic Polysemous Classes. In: Guarino, N.: Formal Ontology in information systems. Proceedings of the First International Conference (FOIS '98), June 6-8, Trento, Italy. Amsterdam 1998: IOS. S Guarino, N.: Formal Ontology and Information Systems. In: Guarino, N.: Formal Ontology in information systems. Proceedings of the First International Conference (FOIS '98), June 6-8, Trento, Italy. Amsterdam 1998: IOS. S Guarino, N.; Welty, Chr.: Evaluating Ontological Decisions with OntoClean. In: Communications of the ACM #2, February 2002 (Vol. 45). Available on-line: ladseb.pd.cnr.it/infor/Ontology/Papers/OntologyPapers.html Miller, G. A.: Nouns in WordNet: A Lexical Inheritance System. In: 5papers.pdf. Princeton Available on-line: ftp://ftp.cogsci.princeton.edu/pub/wordnet/5papers.pdf Miller, G. A.; Beckwith, R.; Fellbaum, Chr.; Gross, D.; Miller, K. In: 5papers.pdf. Princeton Available on-line: ftp://ftp.cogsci.princeton.edu/pub/wordnet/5papers.pdf Oltramari, A.; Gangemi, A.; Guarino, N.; Masolo; C.: Restructuring WordNet‘s Top-Level: The OntoClean approach. Padova Available on-line: WordNet Browser used: 1.6. Latest version is 1.7.1, available on-line for UNIX and Windows systems. Mac and DOS versions are not supported anymore. Free download of data set (also PROLOG version!), browser, documentation. University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002

Klaus M. Frei19 „First of all, we do not intend this [i.e. OntoClean – KMF] as a can- didate for a “universal” standard ontology. Rather, we support the vision of a library of foundational ontologies, reflecting diffe- rent commitments and purposes“ (Oltramari et al. 2002, p. 3 – ita- lics orig). „Finally, we have to point out that the ontology presented here is an ontology of particulars. Properties and relations are therefore not part of its domain“ (ibd. – italics orig). University of Zurich Computational Linguistics Seminar „Wissensrepräsentation in der CL“ Dr. Kai-Uwe Carstensen SS 2002 OntoClean Appendix