Chinese Journal of Computers   Full Text
Title	A Tableau Decision Algorithm for Dynamic Description Logic
Authors	CHANG Liang1),2) SHI Zhong-Zhi1) QIU Li-Rong1) LIN Fen1),2)
Address	1)(Key Laboratory of Intelligent Information Processing, Institute of Computing Technology, Chinese Academy of Sciences, Beijing 100190) 2)(Graduate University of Chinese Academy of Sciences, Beijing 100039)
Year	2008
Issue	No.6(896—909)
Abstract &   Background	Abstract By introducing a dynamic dimension into the description logic, two kinds of dynamic description logics have been proposed in the literatures for representing and reasoning about knowledge of dynamic application domains. But both of them lack efficient decision algorithms. This paper presents a Tableau decision algorithm for the dynamic description logic D-ALCO. D-ALCO is a combination of the description logic ALCO, the dynamic logic, and an action theory based on the possible models approach. In D-ALCO, based on domain ontologies expressed in ALCO, atomic actions are described by specifying their preconditions and effects; With the help of standard action constructors of the dynamic logic, complex actions can be described also; Both atomic actions and complex actions are then used as modal operators in the construction of formulas. The Tableau decision algorithm for D-ALCO forms an elaborated combination of the Tableau algorithm for ALCO, the decision algorithm for propositional dynamic logic, and the embodiment of the possible models approach. The authors prove that the algorithm is terminating, sound and complete for deciding the satisfiability of D-ALCO formulas with the Open World Assumption. The algorithm is flexible and can be extended for more expressive dynamic description logics such as the D-ALCQO and the D-ALCQIO. Keywords dynamic description logic; action theory; satisfiability; Tableau algorithm; decidability Background The description logic (DL) is playing an important role in the Semantic Web, acting as the basis of the W3C- recommended Web ontology language OWL. The main strength of DL is that it offers considerable expressive power going far beyond propositional logic, while reasoning is still decidable. A limitation of the DL is that it can only describe and reason about knowledge of static application domains. In order to represent and process the knowledge about semantic Web services, an obvious concern is to combine in some way the static description of ontologies on the Semantic Web with the dynamic description of computations provided by Web services. In the authors’ previous work, by embracing actions into the DL, a dynamic description logic named DDL was proposed. The DDL provides an effective approach to combine the static description of ontologies with the dynamic description of services. In this paper, the authors focus on the tableau decision algorithm for dynamic description logics. By taking the dynamic description logic D-ALCO as an example, a decision algorithm applicable to the Open World Assumption is proposed. This research is supported by the National Natural Science Foundation of China under grant No.60775035, which title is the Logical Foundation for the Semantic Web Service. It is also partially supported by the National Natural Science Foundation of China (No.90604017), the National High Technology Research and Development Program (863 Program) of China (No.2007AA01Z132) and the National Basic Research Program(973 Program) of China (No.2007CB311004).