Abstract: The KRA Model offers a generic framework to construct the model of the world W. In this paper, the ontology of concept was introduced in the General KRA model and the Abstraction Object Database was extended to Ontology Class which makes the knowledge sharing and reuse possible in the Perception level, the Language level and the Theory level of the KRA model. The three kinds of ontology abstraction operator(set) were also defined;fundamental operator,entity operator set and connection operator set, working on W and ontology class. Furthermore, the mapping between two different ontology classes was given to realize model abstraction and model reverse-abstraction. The abstraction degrec of ontology class was proposed to represent the degree of ontology class and it is as well pointed out that in such a framework, the models of W with different abstraction degrees can be automatically constructed by using abstraction mapping.

Key words: KRA abstraction model, Ontology class, Ontology abstraction operator, Abstraction degree, Hierarchical abstraction model