Petri网共享合成及其在并行系统中的应用

为了使Petri网技术能够应用于MPI并行程序的正确性和性能的验证,提出了Petri网共享合成运算构建MPI并行程序Petri网的算法。对分布式并行处理系统MPI并行程序的结构与消息传递过程进行分析,给出并行程序基本语句与传递函数的Petri网,将Petri网共享合成运算从两个Petri网的共享合成运算推广到并行程序的多个Petri网的共享合成运算,给出了推广定理和证明。提出了共享合成构建MPI并行程序Petri网的算法,并在消息传递并行系统中给出构建MPI并行程序Petri网的应用示例。实验结果表明,共享合成运算是构建MPI并行程序Petri网模型的一种有效方法。     

Petri网控制结构的合成运算

借助于模块化设计、分析思想,定义了Petri网顺序连接、选择、重复、并行等控制结构的合成运算及其对应的关联矩阵的合成运算;给出了合成Petri网的形式描述——网合成表达式;实现了基于子系统的Petri网建立复杂系统的Petri网模型,给出了利用子网的关联矩阵构造合成Petri网的关联矩阵的算法,为合成Petri网的结构性质分析的自动化提供了方法。     

基于Petri网的分布式系统并发进程的死锁检测

分布式系统中的并发进程具有明显的并发、异步及分布性,而Petri网是模拟与分析并发、异步、分布式系统的有效工具.为此通过引入Petri网,给出了分布式系统局部并发进程等待的Petri网模型及死锁检测方法,提出了全链路合成的概念,利用全链路合成技术组装了全局并发进程等待的Petri网模型,给出了判断整个系统是否出现死锁的充分必要条件.     

共享合成Petri网系统的语言递归性与系统活性

在Perri网系统合成操作的研究中,大系统的一些好性质,如活性、无死锁性的判定,是一个重要的研究内容.研究了Petri网系统的一种重要的合成操作--共享合成,着重研究了Petri网系统共享合成的行为关系(语言关系),指出并证明了Petri网系统共享合成过程中语言的递归性质,得到一个并发语言形式的共享合成语言关系式.这个语言关系式为应用Petri网系统对具有并发行为特征的系统进行建模分析提供了一种有效的形式化工具.进而利用这个语言关系式来判定共享合成网系统的活性与无死锁性，得到共享合成网系统活及无死锁的充要条件.最后给出了一些条件,在这些条件下,可用小系统的语言子集来判定共享合成网系统的活性,从而达到用小系统来研究大系统活性的目的.     

Petri网合成理论及应用综述

对于建模和分析物理系统的模型,Petri网在处理并发和冲突方面具有强大的能力.Petri网合成技术将小型Petri网通过一组子网的某些共享位置、某些共享变迁按合成规则综合成复杂网系统,它足Petri网系统建模中一种重要的自底向上的建模方法,适用于具有异步、并发特征的复杂应用环境.综述了 Petri网系统两种合成操作(共享合成、同步合成)理论,然后介绍了国内外研究状况,最后指出了合成技术在柔性制造系统(FMS)和多媒体系统等应用方面的发展热点.     

Petri网语言的同步交运算

Petri网语言是用于系统行为分析的有力工具，利用传统的语言运算并不能很好地刻画Petri网的语言行为，为此，本文给出一种新的Petri网语言运算操作一同步交运算，并就网系统的分解和合成过程中的行为关系，分析了Petri网语言的同步交运算的作用和意义．     

Petri网共享T型子网合成公平性分析

共享T-型子网合成是研究复杂Petri网系统性质的一个有效途径.本文研究了共享T-型子网合成对参与合成的各网系统的公平性的继承关系,给出了合成网保持公平性的充分条件.随后给出的有关制造系统设计的举例,说明了该合成方法的有效性.本文的结果可为Petri网系统合成性质的考察提供有效途径.     

一种基于同步合成构造Petri网进程表达式的方法

Petri网的进程是用于系统行为和状态描述的有效工具,Petri网的进程表达式可以给出系统全部进程的描述,但是对于任意无界Petri网而言求取其进程表达式十分困难.文中首先考察结构简单的S-网的进程行为,给出各种类型的S-网的进程表达式的描述方法.然后拓展了Petri网同步合成的概念,分析了同步合成过程中基本进程段集之间的关系,并利用同步混排给出了进程表达式之间的关系.随后证明了一个Petri网可以通过一组S-网同步合成得到,利用S-网的进程表达式给出了构造Petri网的进程表达式的方法.     

混合式应用共享机制模型的研究

应用共享技术是计算机支持协同工作(CSCW)系统中支持同步协作的关键技术之一．本文通过对应用共享机制的分析，给出了混合式应用共享机制的结构模型，并利用着色Petri网技术建立混合式应用共享的CPN模型．最后，文章还给出了一个模型的实现例子．     

语言表达式到Petri网模型的转化及其算法

已知一个语言的表达式,直接构造产生该语言的Petri网模型是Petri网语言理论中一个重要问题.本文分析、研究同步交错正规表达式中各种运算与Petri网模型的对应转换关系,分别给出正规表达式、α闭包表达式到Petri网模型的转换方法;定义了Petri网的有界覆盖合成运算,研究有界覆盖合成网的语言性质,给出将同步交错正规表达式转换为Petri网模型的算法,从而实现了语言表达式到Petri网模型的等价转化.     

Timing and liveness in continuous Petri nets

Fluidification constitutes a relaxation technique for studying discrete event systems through fluidified approximated models, thus avoiding the state explosion problem. Moreover, the class of continuous models thus obtained may be interesting in itself. In Petri nets, fluidification leads to the so-called continuous Petri nets, which are technically hybrid models. Under infinite server semantics, timing a continuous Petri net model preserves the liveness property, but the converse is not necessarily true, and if the autonomous net model is not live, the timing may transform it into a live model. In this paper, we investigate the conditions on the firing rates of timed continuous models that make a given continuous system live.     

Petri网的组合积网及性能分析

Petri网是一种系统描述和分析的工具 .Petri网组合是由小系统的性质获得大系统性质的一种有效的分析方法 .本文提出了 Petri网的组合积运算 ,包括 Petri网的 型组合积运算和 型组合积运算、Petri网的并积运算 ,讨论了保持网的结构性质的条件 ,为复杂大系统的分析提供了新途径     

Dynamic Slicing of Petri Nets Based on Structural Dependency Graph and its Application in System Analysis

Petri net models are frequently complex and difficult to understand and modify. Slicing technology is very useful in analyzing programs, and has been widely used in specification level for model reduction. So it is necessary to explore slicing methods for Petri nets. This paper proposes a dynamic slicing technique for Petri nets based on the structural dependency graph (SDG). Firstly, the SDG is constructed from the slicing criterion by a backtracking algorithm. Secondly, based on the SDG and a given marking, the dynamic slice can be acquired. As a case study, the proposed method is applied to a control system, and a simulation tool is developed for validating this method and automatically generating the slice. The algorithms can be useful in automatically identifying the parts of the model that affect a state of interest, and provide the basic technical support for alleviating the difficulty of formal verification and analysis.     

A Survey of Petri Net Methods for Controlled Discrete Event Systems

This paper surveys recent research on the application of Petri net models to the analysis and synthesis of controllers for discrete event systems. Petri nets have been used extensively in applications such as automated manufacturing, and there exists a large body of tools for qualitative and quantitative analysis of Petri nets. The goal of Petri net research in discrete event systems is to exploit the structural properties of Petri net models in computationally efficient algorithms for computing controls. We present an overview of the various models and problems formulated in the literature focusing on two particular models, the controlled Petri nets and the labeled nets. We describe two basic approaches for controller synthesis, based on state feedback and event feedback. We also discuss two efficient techniques for the on-line computation of the control law, namely the linear integer programming approach which takes advantage of the linear structure of the Petri net state transition equation, and path-based algorithms which take advantage of the graphical structure of Petri net models. Extensions to timed models are briefly described. The paper concludes with a discussion of directions for future research.     

几种满足汇合性质的Petri网子类

证明活的标识S-图、活的标识T-图、有界的冲突无关的Petri网、有界的标识T．图具有汇合性质,讨论共享合成与同步合成操作对Petri网汇合性质的保持性,得出由上述简单的Petri网子类通过共享合成及同步合成得到的复杂的网系统也具有汇合性质。通过一个具有汇合性质的复杂网系统实例验证该结论。     

ST—组合Petri网的结构性质分析

本文提出ＳＴ－组合Ｐｅｔｒｉ网的概念,讨论了ＳＴ－组合Ｐｅｔｒｉ网对子网的结构性质保持问题,深入研究了ＳＴ－组合Ｐｅｔｒｉ网的结构活性、结构有界性,守恒性,可重复性,相容性,公平性。本文给出的网组合可作为系统合成与分析的有效方法。     

Synthesis a Petri net based control model for a FMS cell

Petri nets have been recognised as a high level formal and graphical specification language for modelling, analysis, and control of concurrent asynchronous distributed systems. This paper presents a PN model, synthesised by an extended version of the knitting synthesis technique. This method, as an incremental design approach, establishes the conditions under which the fundamental behavioural properties of the synthesised systems are fulfilled and preserved. That is, the synthesised models are live, bounded, and reversible (cyclic). A Petri net with the aforementioned properties is called a well-behaved Petri net system which is guaranteed to operate in a deadlock-free, stable, and cyclic fashion. Well-behaved Petri net models, synthesised using the proposed method can be compiled into control codes and implemented as real-time controllers for flexible manufacturing systems. The significance of this paper is due to the application of an extended version of knitting synthesis technique to a real life example of a flexible manufacturing system.     

Petri网共享单链子网合成及其应用研究

本文针对多个企业共用一个加工厂加工某种产品这一类业务处理问题,提出了经由Petri网共享单链子网构成单链子网合成网的解决方案;给出了自由选择网（FC）,非对称选择网（AC）的共享单链子网合成网为各自相应网的充分条件;提出了共享单链子网合成Petri网保持结构活性的条件;本文的结果可为Petri网系统合成的静态和动态性质的考察提供有效途径,具有宽广的应用前景.     

Reachability analysis of real-time systems using time Petri nets

Time Petri nets (TPNs) are a popular Petri net model for specification and verification of real-time systems. A fundamental and most widely applied method for analyzing Petri nets is reachability analysis. The existing technique for reachability analysis of TPNs, however, is not suitable for timing property verification because one cannot derive end-to-end delay in task execution, an important issue for time-critical systems, from the reachability tree constructed using the technique. In this paper, we present a new reachability based analysis technique for TPNs for timing property analysis and verification that effectively addresses the problem. Our technique is based on a concept called clock-stamped state class (CS-class). With the reachability tree generated based on CS-classes, we can directly compute the end-to-end time delay in task execution. Moreover, a CS-class can be uniquely mapped to a traditional state class based on which the conventional reachability tree is constructed. Therefore, our CS-class-based analysis technique is more general than the existing technique. We show how to apply this technique to timing property verification of the TPN model of a command and control (C2) system.