Klaus M. Frei
1
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. http://www.cogsci.princeton.edu/~wn/gloss)
Is WordNet an ontology?
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
2
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
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3
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. Frei
4
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. Frei
5
WordNet by OntoClean
- Confusion between
concepts and individuals
- 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. Frei
6
WordNet
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
7
OntoClean
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
8
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. Frei
9
Apple in WordNet
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
10
WordNet
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
11
OntoClean
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
12
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. Frei
13
WordNet
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
KMF
!
Klaus M. Frei
14
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Apple in WordNet
Redundancies/Ambiguities
Klaus M. Frei
15
WordNet
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Redundancy
Ambiguity
(resolved)
Klaus M. Frei
16
OntoClean
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
17
Conclusion
WordNet
- Psycho-linguistically
motivated, implemented thesaurus
- May be used as an
ontology
- subsumption-based
- 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. Frei
18
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. 221-235.
- 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. 3-15.
- Guarino, N.; Welty,
Chr.: Evaluating Ontological Decisions with OntoClean. In: Communications
of the ACM #2, February 2002 (Vol. 45). Available on-line: http://www.
ladseb.pd.cnr.it/infor/Ontology/Papers/OntologyPapers.html
- Miller, G. A.: Nouns
in WordNet: A Lexical Inheritance System. In: 5papers.pdf. Princeton
1993. 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
1993. 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 2002. Available on-line: http://www.ladseb.pd.cnr.it/infor/Ontology/Papers/OntologyPapers.html
- 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. http://www.cogsci.princeton.edu/~wn
University of Zurich • Computational
Linguistics • Seminar „Wissensrepräsentation in der CL�� • Dr.
Kai-Uwe Carstensen • SS 2002
Klaus M. Frei
19
- „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
