／var／logmarcus chiu

Ontology

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Ontology
  • is the philosophical study of being
  • a set of concepts and categories in a subject area or domain that shows their properties and the relations between them

Ontologists often try to determine what the categories or highest kinds are and how they form a system of categories that provides an encompassing classification of all entities. Commonly proposed categories include:

  • substances
  • properties
  • relations
  • states of affairs
  • events

Ontological Theories

  • Mono-categorical Ontologies hold that there is only one basic category, which is rejected by Poly-categorical Ontologies.
  • Hierarchical Ontologies assert that some entities exist on a more fundamental level and that other entities depend on them. Flat Ontologies, on the other hand, deny such a privileged status to any entity

High Level Ontology of Sorts

Entity Types

  • situation - anything that happens at a time and place
    • state - do not imply a change
    • event - imply a change in the status of other entities
  • quantity - a few, two, 22
  • object
    • concrete - occupy space, are touchable, tangible
      • animated - have life, vigor, spirit
      • in-animated - without life, dull
    • abstract - intangible, they are somehow product of human reasoning
      • temporal  - last week, July
      • non-temporal - justice, pain, odor
    • composite object - an object composed of objects
  • quality - heavy, difficult
  • descriptor - complement entities by stating properties about their spatial or temporal context
    • temporal - by the end of the day, on July 15th
    • local - on the roof, near the stadium

Categories

  • categories are classes or sets of objects that have some common properties (e.g. basketballs, children, dogs)
  • objects are members of category
  • 2 ways of representing categories:
    • unary predicates (e.g. basketball() or basketball(b))
    • reify the category as an object (e.g. basketballs or member(b,Basketballs))
    • reification - the process of regarding something abstract as a material thing
  • an object is a member of category
  • a category can be a subclass of another category
  • all members of a category have the same properties
  • members of a category can be recognized by some properties
  • a category as a whole has some properties
  • inheritance is a property through which more specific concepts adopt the properties of more general concepts
    • fuji apple ⊆ apple ⊆ fruit ⊆ food

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