Research On Dynamic Description Logic For Intelligent Agent

Intelligent agent and multi-agent system have received increased attention in the past few years within the domain of artificial intelligence. With the fast development of Internet, Semantic Web and Grid computing, agent plays an increasingly important role in the dynamic, distributed, heterogeneous and uncertain computing environment. Agent technology is regarded as one of the promising technology to construct scalable, robust, reusable, consistent software system in complex environment. Agent design and programming must be based on the solid theory foundation of knowledge representation and reasoning. Knowledge representation and reasoning, mental state model and internal running mechanisms are three key problems in agent technology.By analyzing the existing agent theory model, agent programming language and action theory, this dissertation focuses on the knowledge representation and reasoning as well as the representation and running mechanism of dynamic systems. The main contributions of this dissertation are as follows:(1) A description logic with default reasoning is proposed, which integrates monotonic reasoning and non-monotonic reasoning while avoiding the difficulty of Reiter's default logic. Based on the description logic with default reasoning, we construct a knowledge base system that incorporates Tbox, Abox and default rules. Then we discuss several reasoning problems including concept satisfiability, default satisfiability, concept subsumption, default subsumption and instance checking. We also present a new algorithm called Tableau-D that is used to check the satisfiability and default satisfiability of concept. A transformation theorem of default satisfiability and default subsumption is attained. Furthermore, we present a five-valued reasoning system to provide hierarchical reasoning services.(2) A dynamic description logic is proposed, which reasonably integrates the static and dynamic knowledge representation and reasoning and thus forms a uniform formal framework. The framework is characterized by explicit semantics, providing decidable reasoning service and supporting effective representation and reasoning of the dynamic process and running mechanism. In the dissertation, the syntax, semantics, basic theory and domain axioms of dynamic description logic are presented, and the basic reasoning problems on the dynamic...