Abstract:XYZ system consists of a temporal logic language XYZ/E and a group of CASE tools based on it. The language XYZ/E is designed to facilitate the software engineering methodologies such as stepwise refinement, specification and verification, rapid-prototyping, and in particular, to be able to represent the dynamic aspects of the real time communicating process. With a uniform framework, it can represent not only the specifications of different abstract levels but also almost every kind of significant features in conventional imperative languages. This paper is the most updated and detailed introduction of this temporal logic language in Chinese.

Abstract:In this paper, a new relation called virtual-real relation in research of deductive database system has been proposed, virtual-real relation can integrate some advantage of real relation and virtual relation, overcome some disadvantage of them, it has a special character in DDBS. After introducing virtual-real relation to DDBS the authors can extend the function of DDBS. Now a virtual-real relation has been realized in DDBS -dUNIFY on SUN-3 workstation and is being applied to CAD and graphic fields.

Abstract:This paper investigates a group of necessary and sufficient conditions for judgement fairness and grouping fairness of bounded Petri nets and fairness of unbounded Petri nets using the rank of incidence matrix. These conditions are very convenient for use.

Abstract:This paper proved that the lowest degree of GI interpolation over 3D triangulation with Be'zier triangular surface patches where only one patch is constructed over one triangle region is quintic and a scheme of constructing lowest degree of GI interpolation over 3D triangulation is described in detail.

Abstract:As pointed out by A. Aggarwal the lower bound proof for convex hull problem of Steele and Yao is only positive when the points are not necessarily in general position. It is nuclear whether their proof can be modified to handle the case where there is no any restriction on the solution set of the problem. In the fixed-order algebraic-descision -tree model this paper solves the problem completely.

Abstract:Inference on a single level may suffers a number of deficiencies, for instance, the rationality of the inference can not be accounted for inside the level, and information acquisition is not human-oriented. This paper introduces a deep-shallow inferential model, called HELl. This model removes some bugs in single-level inferential models.Also, variations of HELI are presented.

Abstract:Optimistic and conservative locking strategies are two different mechanics of concurrency control in distributed data base management systems (DDBMS). This paper proposes a method which combines the above two strategies and awakes it possible to dynamically select the way of transaction processing according to the real recent state of the system, to reduce deadlock and to make the system itself more efficent in concurrency control while remain both features of these two strategies.