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Ontologies and The Real World. Reading: Papers under “Knowledge Representation” under LINKS. Agenda. Taxonomies sample upper level models Different kinds of knowledge Gazetteers Defining concepts An exercise in ontology development

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Ontologies and The Real World

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Ontologies and the real world l.jpg

Ontologies and The Real World

Reading: Papers under “Knowledge Representation” under LINKS


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Agenda

  • Taxonomies

    • sample upper level models

    • Different kinds of knowledge

    • Gazetteers

  • Defining concepts

  • An exercise in ontology development

  • Using ontologies to help in natural language learning tasks


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    Upper Level Models

    • CYC

    • WordNet

    • Omega

    • Suomo


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    CYC

    • http://opencyc.org


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    WordNethttp://wordnet.princeton.edu

    • 118,000 different words

    • 90,000 different word senses

    • 166,000 different word/sense pairs


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    Relations in WordNet

    • Synonymy – antonymy

    • Hyponomy – hypernomy

    • Meronymy – holonymy

    • Tryponomy

    • Entailment relations


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    OMEGA

    • http://omega.isi.edu/doc/browsers.html


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    Suggested Upper Merged Ontology (SUMO)

    • Collaborative effort across sites

    • Will provide definitions for standard terms

    • Will provide a foundation for domain specific efforts

    • Will ultimately contain 1000-2500 terms and 10 definitions per term


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    Questions

    • What criteria should we use in deciding what goes into the upper level?

    • How do we know if we were right?

    • How well do these hierarchies do at capturing general distinctions?


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    Other kinds of knowledge

    • Professions

    • Locations


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    Using knowledge in machine learning

    • Categorization of text

    • We learn from the association of words with categories

    • Could world knowledge yield better results?


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    Newsblaster

    • http://newsblaster.cs.columbia.edu


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    • Call

    • ?


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    • How could we use this kind of knowledge for the homework assignment?

    • (Note: not required)


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