Abstract:Datalog with negation(called Datalog～ )is an extension of Datalog.The fixpoint characteristic of well -founded model semantics of Datalog～ is discussed in this paper.At first,the stability transformation is revisited, and a new operator OP and its fixpoint are defined.Based on this,the oscillating fixpoint model semantics is defined.Then,it is shown that for any datalog～ program the oscillating fixpoint model is identical to its well-founded model,and so,the former can be viewed as a constructive definition of the latter.

Abstract:This paper studies the relationship between data models and the type systems of programming languages.It is noted that data models can be described in terms of types and the relationships among types.The meta model which is used to describe data models is proposed and established on the PCT type language,which is developed by combining the C+ + type system and the first order predicate calculus.Various aspects of data models can be successfully described in PCT.

Abstract:This paper presents an algorithm for determining convexo-concave venices of an arbitrary polygon. The algorithm requires O(n²logn)multiplications and O(n²)comparisons.

Abstract:In object-oriented programming,the inheritance is one of the factors which induce semantic complexity.In this paper,the coexistence and relationship of inheritance,as a mechanism for sharing codes,and subtyping,which expresses specialization in functionality, are discussed.The concept of type, which states that types are behavioral specifications of objects,that is,the sets of named operations,is presented. Based on this concept, types, classes and subtyping relationship are described formally.

Abstract:This paper describes the paraconsistent circumscription by application of circumscription in a paraconsistent logic.It turns out that the paraconsistent circumscription can be characterized by the minimal semantics which is nonmonotonic and paraconsistent.It brings them advantages in two respects:nonmonotonic logic would be nontrivial while there was a contradiction,and paraconsistent logic would be equivalent to classical logic while there was no effect of a contradiction.

Abstract:In order to efficiently manage data and knowledge related with assemblies,and supply necessary information for assembly planning and real-time execution,it is necessary to build the knowledge bases for intelligent robotic assembly systems(also called assembly knowledge bases).In this paper,after the research background is introduced,the system architecture and the knowledge model are proposed;then,the knowledge definition language interface EXPRESS language is described,which is consistent with the knowledge model.Finally,this paper gives the conclusion.

Abstract:This paper presents the implementation frameworks of two client-server DBMS architectures,which are based on our multiuser DBMS.In these two architectures,the layers of database system software are seperated to client side and server side reasonably.Experiment results are shown to indicate the performance aspect of the client-server architectures and original multiuser DBMS to different kinds of application.

Abstract:Modeling of the human body is a basic problem in computer animation of the human body.This paper presents a method which uses combination of polyhedra to establish an initial rough design of the human body and polyhedral subdivision to approximate the curve surface of the realistic human body.In addition,it also considers the dynamic features of the human body and creates a fine condition for the establishment of the human body animation.

Abstract:MKL,an algorithm for meta-knowledge learning,is presented in NDKAS,which is a knowledge acquisition system.On the basis of classification and abstraction, it can induces meta-knowledge which is used to effectively organize rules in knowledge base in binary-tree structure,which satisfies the essential properties of meta-knowledge.The structural representation of meta-knowledge,the algorithm description of MKL and the proof of satisfaction of the essential properties are given in the paper.An example of MKL application is also described.