Oblog-2: A hybrid knowledge representation system for defeasible reasoning

ABSTRACT

Oblog-2 is a hybrid knowledge representation system comparable to Krypton and KL-TWO. It combines a terminological reasoner with a Prolog-like inference mechanism. The terminological component supports the description of type and attribute taxonomies. Entities are instances of a set of types. Procedures for determining the values of attributes are Horn clause rules indexed by type. The known types of an entity determine its set of applicable rules, which changes as our knowledge about the types of the entity is refined, supporting a form of defeasible reasoning. Oblog-2 has been designed for modeling legal domains. Laws can be represented as general rules with exceptions, a technique traditionally used in the law, together with burden of proof rules, for reaching decisions when less than perfect information is available.

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INDEX TERMS

Primary Classification:
  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE

Additional Classification:
  H. Information Systems
  H.1 MODELS AND PRINCIPLES
      H.1.2 User/Machine Systems
          Subjects: Human information processing

  I. Computing Methodologies
  I.2 ARTIFICIAL INTELLIGENCE
      I.2.3 Deduction and Theorem Proving
          Subjects: Uncertainty, "fuzzy," and probabilistic reasoning

General Terms:
Design, Human Factors, Languages