S-组合Petri网的活性分析与实现

设Σ１＝（Ｎ１，Ｍ１），Σ２＝（Ｎ２，Ｍ２）是两个Ｐｅｔｒｉ网，且不含有冻结标志，Ｎｉ＝（Ｓｉ，Ｔｉ；Ｆｉ），ｉ＝１，２，Ｔ１∩Ｔ２＝Φ，Ｓ１∩Ｓ２≠Φ，本文定义了Σ１，Σ２的Ｓ－组合Ｐｅｔｒｉ网Σｓ，通过引入Ｐｅｔｒｉ网互逆位置序偶的概念，深入研究了Σｓ的活性，给出了Σｓ有界活的几个判定条件。若Σ１，Σ２是两个活的Ｐｅｔｒｉ网，最后提出了一种实现Ｓ－组合Ｐｅｔｒｉ网活性的控制装置。     

S-网的活性分析

讨论了一类结构简单的Petri网-S-网的活性问题，给出了各类S-网的活性判定定理并给出了判定算法．算法主要计算工作是变迁的前序库所集和后继变迁集以及极大强连通子网的判断，这三个过程实际上是一个树的搜索过程，因此算法易于实现，判定效率也大大提高．     

S-组合Petri网的进程特性分析

Petri网进程是反映Petri网动态特性的重要工具.Petri网的进程表达式可以给出系统全部进程的描述,但是对于求取Petri网的进程表达式时用到的基本子进程,其求取通常是比较困难.通过分析Petri网S-组合过程中满足的进程特性,给出S-组合网与子网的基本子进程之间的关系,即S-组合Petri网的闭基本子进程的集合是子网的闭基本子进程的集合的并集.这样,就将求取结构复杂Petri网的基本子进程的问题转化为求取其结构简单的组合子网的基本子进程的问题,为求取结构复杂Petri网的基本子进程提供了一种方法.     

T-组合Petri网的活性和公平性分析

同步合成是研究复杂Ｐｅｔｒｉ网系统性质的有效途径．文中通过引入可引发变迁序偶的概念,研究了Ｔ－组合（同步合成）Ｐｅｔｒｉ网对子网的活性和公平性继承关系,给出了一组Ｔ－组合Ｐｅｔｒｉ网活或公平的充要条件和充分条件．这些结果对网组合同步设计具有重要的指导意义     

T—组合Petri网络活性和公平性分析

同步合成是研究复杂Ｐｅｔｒｉ网络系统性质的有效途径。文中通过引入可引发变迁序偶的概念,研究了Ｔ－组合（同步合成）Ｐｅｔｒｉ网对子网的活性和公平性继承关系,给出了一组Ｔ－组合Ｐｅｔｒｉ网活或公平的充要条件和充分条件。这些结果对网组合同步设计具有重要的指导意义。     

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     

一种基于逻辑Petri网的Web服务簇组合方法

Web服务组合是实现快速服务增值和软件重用的重要方式,但现有的静态服务组合和动态服务组合方式都有待于进一步完善.文中集成静态服务组合和动态服务组合的优点,提出了一种在虚拟层面上基于服务簇进行服务组合的思想;研究并提出了一种基于服务簇的服务组合方法,并应用逻辑Petri网对其进行形式化建模描述;给出了服务簇网的基本组合模型,并分别对其完备性继承作了分析;研究了服务簇网组合的代数运算性质.最后,通过实验证明了服务簇网组合运算的可行性和有效性.     

概率逻辑可能世界的Petri网模型

本文研究概率逻辑中推导可能世界的Ｐｅｒｔｉ模型，该模型为可能世界的产生提供有效算法，这个算法被证明是正确的，它可以产生所有的一致的可能世界，文章中还分析了算法的复杂性，通过同其它方法的比较可知：此Ｐｅｔｒｉ网模型是概率逻辑可能世界推导的简单、实用和图形化的工具。     

线性逻辑,Petri网和并发计算

1.线性逻辑和张量理论在古典逻辑的 Gentzen 型矢列演算中Girard 去除弱规则和缩规则,发展起一种新型逻辑系统——线性逻辑(简记为 LL)。它不同于古典逻辑,本质上是一种事态逻辑(logic of situation),或者是一动作逻辑(logic of action),强调系统的动态特征与并发计算紧密相关。结构规则的去除自然在 LL 中导致了两种类型的连接词:乘性连接词和加性连接词,     

Petri网用于Horn子句的逻辑推论

这篇论文探索了命题逻辑的Horn子句的Petri网模型,求解逻辑推论Petri网模型的T—不变量是求解逻辑推论的核心步骤,本文提供了计算T—不变量的算法,这些算法基于归约的思想,另外,在算法中利用单字母规则、纯字母规则和割裂规则可提高算法的速度和简化算法的复杂性。     

Necessary and sufficient liveness condition of GS3PR Petri nets

Structural analysis is one of the most important and efficient methods to investigate the behaviour of Petri nets. Liveness is a significant behavioural property of Petri nets. Siphons, as structural objects of a Petri net, are closely related to its liveness. Many deadlock control policies for flexible manufacturing systems (FMS) modelled by Petri nets are implemented via siphon control. Most of the existing methods design liveness-enforcing supervisors by adding control places for siphons based on their controllability conditions. To compute a liveness-enforcing supervisor with as much as permissive behaviour, it is both theoretically and practically significant to find an exact controllability condition for siphons. However, the existing conditions, max, max′, and max″-controllability of siphons are all overly restrictive and generally sufficient only. This paper develops a new condition called max*-controllability of the siphons in generalised systems of simple sequential processes with resources (GS³PR), which are a net subclass that can model many real-world automated manufacturing systems. We show that a GS³PR is live if all its strict minimal siphons (SMS) are max*-controlled. Compared with the existing conditions, i.e., max-, max′-, and max″-controllability of siphons, max*-controllability of the SMS is not only sufficient but also necessary. An example is used to illustrate the proposed method.     

基于双枝模糊逻辑和模糊着色Petri网的攻击模型

定义了一种基于双枝模糊逻辑和模糊着色Petri网的网络攻击模型, 从对攻击起促进和抑制作用这两方面对网络攻击进行综合考虑与分析, 同时对模糊规则库中的不同变量用不同的颜色来区分, 因此可构成一个简明的BBFCPN模型。在此基础上, 给出了BBFCPN模型的基本推理规则和推理算法。针对攻击实例的分析进一步验证了提出的模型及相关推理算法。     

层次结构的Petri网

Petri网是一个很好地描述与分析并行系统的模型。但在实际应用中,如果系统过大或较复杂时,会遇到结点数过多的问题。介绍了着色网和几种层次结构的Petri网,包括位置/转移精化网、对象网以及开放网等;分析和比较了这几种模型用以减少结点数和引入层次结构的方法,而且从结构上讨论了它们相互之间的关系。     

Compositional analysis of Petri nets

Foundations of compositional analysis of Petri nets are presented. This analysis consist of the determination of properties of a given Petri net from the properties of its functional subnets. Compositional analysis covers the investigation of behavioral and structural properties of Petri nets with the help of matrix methods that use fundamental equations and invariants. The exponential acceleration of computations as a function of the dimensionality of a net is obtained. __________ Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 143–154, January–February 2006.     

Property analysis of logic Petri nets by marking reachability graphs

Logic Petri nets （LPNs） are suitable to describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. To investigate the dynamic properties of LPNs directly, a new method for analyzing LPNs is proposed based on marking reachability graphs in this paper. Enabled conditions of transitions are obtained and a marking reachability graph is constructed. All reach- able markings can be obtained based on the graph; the fairness and reversibility of LPNs are analyzed. Moreover, the computing complexity of the enabled conditions and reachable markings can be reduced by this method. The advantages of the proposed method are illustrated by examples and analysis.     

Property analysis of logic Petri nets by marking reachability graphs

Logic Petri nets (LPNs) are suitable to describe and analyze batch processing functions and passing value indeterminacy in cooperative systems. To investigate the dynamic properties of LPNs directly, a new method for analyzing LPNs is proposed based on marking reachability graphs in this paper. Enabled conditions of transitions are obtained and a marking reachability graph is constructed. All reachable markings can be obtained based on the graph; the fairness and reversibility of LPNs are analyzed. Moreover, the computing complexity of the enabled conditions and reachable markings can be reduced by this method. The advantages of the proposed method are illustrated by examples and analysis.     

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.     

A parameterized liveness and ratio-enforcing supervisor for a class of generalized Petri nets

The work proposes a synthesis method of supervisors for flexible manufacturing systems modeled by a class of generalized Petri nets. A concept of resource usage ratios (RU-ratios) is first presented to describe the occupation degree of a resource by an operation. Next, an intrinsically live structure characterized by a special numerical relationship between arc-weights and initial markings is investigated from a perspective of RU-ratios. Then, a new kind of supervisors is synthesized on the ground of the generic nature of the intrinsically live structure. Such a supervisor can achieve the purposes of both liveness-enforcement and resource usage ratio-enforcement of the system under consideration. Given a plant, it is easy to determine the topological structure of such a supervisor and the number of monitors is bounded by that of resources used in the plant. In addition, when the configuration of the plant model changes, the supervisor can be reusable through adjusting control parameters only without rearrangement of connections. This makes it easy enough and intuitive to be used by industrial practitioners. Instead of maximal behavioral permissiveness, it pursues a precise usage of shared resources that are limited and valuable. Several examples are used to illustrate the proposed methods.