Research On Recursion Fixed Point Semantics Of Ontology Knowledge Base

ABSTRACT:As an effective mechanism for knowledge representation, description logic is an important logic basis for building formalized ontology knowledge base. Nowadays, ontology knowledge base based on description logic is widely used in communication between agents, heterogeneous information source integration, Semantic Web, etc. In the research area of description logic, there are several problems. First, the TBox of description logic can't be defined by recursion definition when containing negative definition. Second, we cannot query negative information in ontology knowledge base based on description logic.Firstly, this thesis illustrates the problem that recursion definition can't be contained in the semantic model of the TBox when containing negation definition, and promotes a rule of using recursion definition and negation definition, promotes stratified TBox theory.Secondly, based on the grammatical form of description logic and the construction characteristics of TBox, extends the theorem related to recursion fixed point theory within the grammatical structure in the description logic. Finally, this thesis proves that the recursion fixed point theory can also be used for the semantic model computation of a stratified TBox in ontology knowledge base.This thesis extends the recursion fixed point theory of stratified program in ontology knowledge base. It not only solves the problem of defining semantic model of TBox in description logic when containing both the negation definition and recursion definition, but also provides a theoretical basis of negative information querying in ontology knowledge base based on description logic.There are 4 figures,3 tables and 32 references in the thesis.