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Ontologies and The Real World

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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  1. Ontologies and The Real World Reading: Papers under “Knowledge Representation” under LINKS

  2. 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

  3. Upper Level Models • CYC • WordNet • Omega • Suomo

  4. CYC • http://opencyc.org

  5. WordNethttp://wordnet.princeton.edu • 118,000 different words • 90,000 different word senses • 166,000 different word/sense pairs

  6. Relations in WordNet • Synonymy – antonymy • Hyponomy – hypernomy • Meronymy – holonymy • Tryponomy • Entailment relations

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

  8. 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

  9. 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?

  10. Other kinds of knowledge • Professions • Locations

  11. Using knowledge in machine learning • Categorization of text • We learn from the association of words with categories • Could world knowledge yield better results?

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

  13. Call • ?

  14. How could we use this kind of knowledge for the homework assignment? • (Note: not required)

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