并行计算通信库测试方法研究及实践

并行计算通信库的测试在并行计算系统中起着重要的作用.对通信库的测试一般都是通过设计一些测试程序对库的各个或几个部分分别进行单独隔离测试.但是有许多库中的错误用这种隔离测试方法测不出来,只有当库的多个部分以某种复杂的、有机的方式组合运行时才会暴露出来.而这种复杂的、有机的组合方式,从设计库的测试角度看很难形成.提出两种新的测试方法,根据通信库结构的分层特性,利用可移植的上层库的测试程序来测试下层库.上层库的测试程序也可看做是下层库的应用程序,但与一般的下层库应用程序不同,它几乎覆盖了下层库的各个部分,且有机地将它们组合起来,运行时形成某种复杂的形态,而仅用下层库的测试程序往往达不到这种形态.这样,逃过下层库测试程序的错误就可能暴露出来.     

χ-演算与π-演算的语义比较研究

Through the comparison of syntactic structure,operational semantics and algebraic semantics between χ-calculus and π-calculus, this paper concludes that χ-calculus has more succinct syntactic structure,more explicit operational semantics,more intuitionistic algebraic semantics and more favorable algebraic property. And a translation from π-calculus to χ-calculus is presented.     

A functional presentation of Pi calculus

From the very beginning process algebra introduced the dichotomy between channels and processes. This dichotomy prevails in all present process calculi. The situation is in contrast to that withlambda calculus which has only one class of entities-the lambda terms. We introduce in this papera process calculus called Lamp in which channels are process names. The language is more uniform than existing process calculi in two aspects-. First it has a unified treatment of channels and processes.There is only one class of syntactical entities-processes. Second it has a unified presentation ofboth first order and higher order process calculi. The language is functional in the sense that lambda calculus is functional. Two bisimulation equivalences, barbed and closed bisimilarities, are proved to coincide.A natural translation from Pi calculus to Lamp is shown to preserve both operational and algebraic semantics. The relationship between lazy lambda calculus and Lamp is discussed.     

空间分析数据库的研究方法及技术

通过大量文献研究 ,分析了空间分析数据库的研究平台、研究方法和技术 ,以及各种研究平台的优缺点 .重点讨论了基于 Realms的空间数据类型、ROSE代数、基于可扩充 DBMS的空间分析数据库的研究方法和技术 ,以及同类系统的不足和需研究解决的问题 ,并指出 Realm s可以有效地表示二维的空间数据及支持空间拓扑操作算法 .文中还分析研究了基于主存数据库技术和 ROSE代数的空间存储管理子系统 ,并指出把它与可扩充数据库管理系统或具有 ADT机制的 DBMS进行集成 ,是研究空间分析 DBMS的有效途径     

Representing short-term observations of moving objects by a simple visual language

In a variety of dynamical systems, formations of motion patterns occur. Observing colonies of animals, for instance, for the scientist it is not only of interest which kinds of formations these animals show, but also how they altogether move around. In order to analyse motion patterns for the purpose of making predictions, to describe the behaviour of systems, or to index databases of moving objects, methods are required for dealing with them. This becomes increasingly important since a number of technologies have been devised which allow objects precisely to get traced. However, the indeterminacy of spatial information in real world environments also requires techniques to approximate reasoning, for example, in order to compensate for small and unimportant distinctions which are due to noisy measurements. As a consequence, precise as well as coarse motion patterns have to be dealt with.A set of 16 atomic motion patterns is proposed. On the one hand, a relation algebra is defined on them. On the other hand, these 16 relations form the basis of a visual language using which motion patterns can easily be dealt with in a diagrammatic way. The relations are coarse but crisp and they allow imprecise knowledge about motion patterns to be dealt with, while their diagrammatic realisation also allow precise patterns to get handled. While almost all approaches consider motion patterns along arbitrary time intervals, this paper in particular focuses on short-term motion patterns as we permanently observe them in our everyday life.The bottom line of the current work, however, is yet more general. While it has been widely argued that it makes sense to use both sentential and diagrammatic representations in order to represent different things in the same system adequately (and hence differently), we argue that it makes even sense to represent the same things differently in order to grasp different aspects of one and the same object of interest from different viewpoints. We demonstrate this by providing both a sentential and a diagrammatic representation for the purpose of grasping different aspects of motion patterns. It shows that both representations complement each other.     

Sparse shape functions for tetrahedral <Emphasis Type="Italic">p</Emphasis>-FEM using integrated Jacobi polynomials

Summary In this paper, we investigate the discretization of an elliptic boundary value problem in 3D by means of the hp-version of the finite element method using a mesh of tetrahedrons. We present several bases based on integrated Jacobi polynomials in which the element stiffness matrix has nonzero entries, where p denotes the polynomial degree. The proof of the sparsity requires the assistance of computer algebra software. Several numerical experiments show the efficiency of the proposed bases for higher polynomial degrees p.      

基于代数神经网络的不确定数据知识获取方法

定义了代数神经元、代数神经网络,讨论了不确定数据知识获取的数学机理,设计出一类单输入,单输出的三层前向网络来获取知识的代数神经网络模型,给出一种基于代数神经网络知识获取的方法,通过该网络的学习,能确定任意一组给定数据的目标函数的逼近式。     

An Algorithm for Timing Verification of Systems Constrained by Min–max Inequalities

To determine the maximum separation between events for nonrepetitive systems with max and linear constraints, there are the “iterative tightening from above” (ITA) approach and the “iterative tightening from below” (ITB) approach. Since such systems can be formulated as systems constrained by min–max inequalities, this paper gives an algorithm named MMIMaxSep for solving min–max inequalities. The algorithm is a generalization and a mathematically elegant reformulation of Yen et al.’s MaxSeparation algorithm which uses the ITB approach. Our numerical experiments indicate that MMIMaxSep is very efficient. Moreover, MMIMaxSep has a unique advantage of being able to directly handle tree-represented min–max functions, and its complexity is closely related to the complexity of computing cycle time of min–max functions.

Duplication of constants in process algebra

The constant 0 (or δ, nil) has different roles in process algebra: on the one hand, it serves as the identity element of alternative composition, on the other hand, it stands for a blocked atomic action or for livelock. When extensions with timing are considered, these roles diverge. We argue that it is better to use two separate constants 0˙ and 0 for the different usages.With respect to the termination constant 1 (or , skip), the situation is comparable: on the one hand, it serves as the identity element of sequential composition, on the other hand, it serves as the identity element of parallel composition, and stands for a skipped atomic action. We have separate constants 1˙ and 1 for the different usages.We set up a theory of process algebra, starting out from these four constants in their respective roles. We do this first for the untimed theory, and work out the extension to discrete timing and relative timing in detail. We indicate how extensions involving dense timing or absolute timing are to be handled. All extensions are conservative.     

On a quasiorder on the class of monounary algebras

In the paper we introduce a relation on the class of monounary algebras by means of -homomorphisms. It is a quasiorder. We take a subclass of containing monounary algebras satisfying the property We characterize algebras in by the notions of a degree and properties of their -endomorphisms. We apply the results to finite monounary algebras. Supported by grant VEGA 1/0161/03