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  • × author_ss:"Fischer, D.H."
  • × theme_ss:"Wissensrepräsentation"
  1. Fischer, D.H.: ¬Ein Lehrbeispiel für eine Ontologie : OpenCyc (2004) 0.00 
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    Abstract
    Es wird ein einführender Überblick über das seit Frühjahr 2002 allgemein verfügbare Ontologiesystem OpenCyc und seine gegenwärtige Wissensbasis gegeben. Das System ist Prototyp eines logikbasierten Wissensrepräsentationssystems und der lnhalt der fortschreib-baren Wissensbasis ist eine universelle Dachontologie, die als ein Extrakt aus langjähriger Erfahrung mit ihrer Anwendung angesehen werden kann. Die Wissensrepräsentationssprache CycL von OpenCyc konkurriert mit der bisher weniger ausdrucksstarken Sprache OWL, die von den W3C-Gremien für das "Semantic Web"standardisiert wird.
    Source
    Information - Wissenschaft und Praxis. 55(2004) H.3, S.139-142
  2. Fischer, D.H.: From thesauri towards ontologies? (1998) 0.00 
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    Abstract
    The ISO 2788 guidelines for monolingual thesauri contain a differentiation of "the hierarchical relationship" into "generic", "partitive", and "instance", which, for purposes of document retrieval, was deemed adequate. However, ontologies, designed as language inventories for a wider scope of knowledge representation, are based on all these and some more logical differentiations. Rereading the ISO 2788 standard and inspecting the published Cyc Upper Ontology, it is argued that the adoption of the document-retrieval definition of subsumption generally prevents the conception or use of a thesaurus as a substructure of an ontology of the new kind as constructed for AI applications. When a thesaurus is used for fact description and inference on fact descriptions, the instance-of relationship too should be reconsidered: It may also link concepts and metaconcepts, and then its distinction from subsumption is needed. The treatment of the instance-of relationship in thesauri, the Cyc Upper Ontology, and WordNet is described from this perspective
  3. Fischer, D.H.: Converting a thesaurus to OWL : Notes on the paper "The National Cancer Institute's Thesaurus and Ontology" (2004) 0.00 
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    Abstract
    The paper analysed here is a kind of position paper. In order to get a better under-standing of the reported work I used the retrieval interface of the thesaurus, the so-called NCI DTS Browser accessible via the Web3, and I perused the cited OWL file4 with numerous "Find" and "Find next" string searches. In addition the file was im-ported into Protégé 2000, Release 2.0, with OWL Plugin 1.0 and Racer Plugin 1.7.14. At the end of the paper's introduction the authors say: "In the following sections, this paper will describe the terminology development process at NCI, and the issues associated with converting a description logic based nomenclature to a semantically rich OWL ontology." While I will not deal with the first part, i.e. the terminology development process at NCI, I do not see the thesaurus as a description logic based nomenclature, or its cur-rent state and conversion already result in a "rich" OWL ontology. What does "rich" mean here? According to my view there is a great quantity of concepts and links but a very poor description logic structure which enables inferences. And what does the fol-lowing really mean, which is said a few lines previously: "Although editors have defined a number of named ontologic relations to support the description-logic based structure of the Thesaurus, additional relation-ships are considered for inclusion as required to support dependent applications."

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