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.     

带赋值符号迁移图的局部优化算法

带赋值符号迁移图（ＳＴＧＡ）是刻画一般传值进程的抽象计算模型,在ＳＴＧＡ上可以用“ｏｎ－ｔｈｅ－ｆｌｙ”实例化算法来验证传值进程之间的互模拟等价。由于ＳＴＧＡＡ的一个结点对应于具体迁移图的许多结点,在ＳＴＧＡ上所作的优化对提高互模拟判定算法的时间和空间效率会产生很大的影响。     

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.     

高阶惯性环节代数等价观测器简易转换方法

为快速计算出代数等价观测器(AEO)的参数对控制系统的影响,基于高阶惯性环节代数等价观测器工程应用的实际,并参照矩阵的Jordan标准型,定义了广义Jordan型矩阵块JBS,通过数学分析给出转换矩阵P的简捷计算方法,为揭示AEO之间的内在关系提供一个有效途径。该方法不仅有助于调节系统的设计,而且通过适当的运用,还能使其达到更加有益的效果。在某电厂600 MW单元机组锅炉过热器蒸汽温度调节系统中的应用案例,证明了所提方法的实用性和有效性。     

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.      

移动进程演算中的开互模拟

该文就移动进程演算中的弱开同余关系进行了研究。文中考虑了一种简单的非确定性移动进程演算模型,证明了Milner的三条tau规则在有等名测试算子时不足以将强开同余关系的完全公理化系统提升到同余关系的完全公理化系统,文中提出了第四条tau规则,处理了在前缀操作下的等名测试算子,并证明了强开同余关系的完全公理化系统加上四条tau规则可得到弱开同余关系的完全公理化系统。该文的结论否定了关于Milner的三条tau规则足以将π－演算中的强同余关系的完全公理化系统提升到弱同余关系的完全公理化系统的猜想。     

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.