一种利用UML的Petri网软件实现方法

Petri网既是一种图形化建模工具,又是一种形式化数学工具。Petri网具有对并发、并行、分布、异步系统进行验证仿真的能力。但是,Petri网是用来描述和分析要开发的系统模型的工具。不是计算机的实现工具,必须要通过一定的方法才能将Petri网用软件来实现。由于UML(统一建模语言)具有友善的用户界面,易于编程实现,故提出一种利用UML作为过渡的Petri网软件实现方法。     

基于Time Petri Nets的实时系统资源冲突检测

Time Petri Nets在实时系统的建模和性能分析中得到广泛应用,而冲突是Petri网及其扩展模型的重要行为,解决冲突是正确分析模型动态行为的关键.目前随机Petri网、混合Petri网和区间速率连续Petri网的冲突检测方法由于没有考虑到时间约束因此无法在TPN网中使用.时间约束的引入使得Time Petri Nets模型的使能和触发语义比Petri网模型的语义复杂,冲突检测变得更加困难.为了计算冲突发生的时间和概率,首先根据时间约束,给出了变迁持续使能时延迟区间的计算方法,并证明了该方法的合理性和完备性;然后在此基础上定义并证明了Time Petri Nets模型中不冲突的检测方法;并提出了Time Petri Nets模型的冲突检测方法,给出了冲突时间区间和变迁实施概率的计算方法;最后通过实例验证说明了该方法的正确性和有效性.     

一类Petri网系统的活性

Petri网是一种用来研究具有异步、并发特征的离散事件系统的合适的工具，当用Petri网来模拟一个实际系统时，关心的问题之一就是要确定这个Petri网模型是否具有一些所期望的特生，如活性、有界性等，这些特性均是系统的重要动态行为，该文基于文献[1]给出了Petri网的一子类，即弱化非自控网（Weak Extended Non SelfControlling Nets,简称WENSeC网），该类网覆盖了扩展自由选择网和扩展非自控网，文中提出了并证明了WENSeC网系统活性的的充分必要条件满足死锁－陷阱性质，同时对WENSeC网的一子类，通过转化方法，证明了该类结构有界网的结构活判定算法可借用扩非自控网的有关结果也是多项式时间算法。     

Petri网在C3I系统仿真建模中的应用

建模仿真技术是C^3I系统性能评估、C^3I系统仿真分析与设计的一个重要方法。该文介绍了Petri网的基本概念,说明了Petri网建模的特征;给出了一种应用于C^3I系统仿真研究的建模方法：应用Petri网对C^3I系统进行分析与设计,实现从C^3I系统的组织框图到Petri网数学模型的转换;指出了Petrl网在C^3I系统仿真建模方面的不足和改进方向。最后,该文给出了用Petri网建模的一个简单应用实例。     

Implementing Coloured Petri Nets Using a Functional Programming Language

Coloured Petri Nets (CPNs) are a graphically oriented modelling language for concurrent systems based on Petri Nets and the functional programming language Standard ML. Petri Nets provide the primitives for modelling concurrency and synchronisation. Standard ML provides the primitives for modelling data manipulation and for creating compact and parameterisable CPN models.Functional programming and Standard ML have played a major role in the development of CPNs and the CPN computer tools supporting modelling, simulation, verification, and performance analysis of concurrent systems. At the modelling language level, Standard ML has extended Petri Nets with the practical expressiveness required for modelling systems of the size and complexity found in typical industrial projects. At the implementation level, Standard ML has been used to implement the formal semantics of CPNs that provide the theoretical foundation of the CPN computer tools.This paper provides an overview of how functional programming and Standard ML are applied in the CPN modelling language and the supporting computer tools. We give a detailed presentation of the key algorithms and techniques used for implementing the formal semantics of CPNs, and we survey a number of case studies where CPNs have been used for the design and analysis of systems. We also demonstrate how the use of a Standard ML programming environment has allowed Petri Nets to be used for the implementation of systems.     

模糊Petri网的反馈控制研究

本文首先将模拟技术应用于Ｐｅｔｒｉ网中，得到模糊Ｐｅｔｒｉ网模型，然后基于Ｐｅｔｒｉ网中的库所湾量的概念，在普通Ｐｅｔｒｉ网的反馈控制基础上提出了一种模型Ｐｅｔｒｉ网的反馈控制方法。该方法使得对复杂系统的模糊Ｐｅｔｒｉ多控制器的系统设计成为可能。     

A user-centric federated single sign-on system

Current identity management systems are not concerned with user privacy. Users must assume that identity providers and service providers will ensure their privacy, which is not always the case. This paper proposes an extension of the existing federated single sign-on (FSSO) systems that adopts the beneficial properties of the user-centric identity management (UCIM) model. This new identity management system allows the users to control and enforce their privacy requirements while still retaining the convenience of single sign-on over a federation of service providers. Colored Petri Nets are used to formally model the new identity management system to provide assurance that the privacy goals are achieved. To our knowledge, Colored Petri Nets have not been used to model privacy in identity management systems before.     

A dynamic Petri net model for iterative and interactive distributed multimedia presentation

Object Composition Petri Nets, Priority Petri Nets, Dynamic OCPN, and Enhanced P-Nets have extended the original Petri Net to achieve the modeling of media synchronization and asynchronous user interactions during multimedia playback. The dynamic Petri Net (DPN) has been conceptualized to tackle existing problems in these two areas of modeling distributed multimedia systems. DPN features dynamic modeling elements which allows iteration and hence is able to reduce graph sizes of synchronous playback models while allowing greater details to be shown. DPN also introduces asynchronous event handling techniques that are powerful and effective. DPN was used in the design and modeling of a multimedia orchestration tool which is a typical representation of an application that works in a distributed multimedia system.     

一类DEDS状态反馈控制器综合的新方法

对具有无穷状态空间的并发离散事件动态系统提出了一种基于Petri网图示的矩阵代数综合方法.该方法借助于对Petri网的结构分解可以用于结构无竞争Petri网描述的一类离散事件动态系统状态反馈控制器的离线综合.     

基于加权FPN的聚驱综合调整系统决策分析

模糊Petri网(Fuzzy Petri Nets, FPN)是一种适合于描述异步并发事件的计算机系统模型,可以有效地对并行和并发系统进行形式化验证和决策分析.针对聚驱综合调整系统知识具有不确定性和模糊性的特点,给出了基于加权模糊产生式规则的加权FPN决策模型.在此模型的基础上,给出了决策推理过程的形式化推理算法.算法考虑了推理过程中的众多约束条件,将复杂的推理过程采用矩阵运算来实现,充分利用了FPN的并行处理能力,使决策推理过程更加简单和快速.并以压裂方式调整为例,说明了该模型具有直观、表达能力强和易于推理等优点,具有较强的实用价值.     

基于XML的生物代谢Petri网模型的标准化

针对分析生物代谢网络的需要，构建了生物代谢Petri网模型建模环境，并采用基于XML的Petri网标记语言PNML为标准，利用DOM实现XML解析，完成Petri网模型的标准化，通过对代谢网络Petri网模型实例的仿真，验证了标准化模型的正确性。     

基于Stateflow的Petri网仿真方法

Stateflow是matlab环境下与simulink整合在一起的专门用来对复杂响应系统和事件驱动系统进行仿真的工具箱。应用其对Petri网模型进行仿真,提出了一种对Petri中资源的分类方法,根据petri网中资源的流通方式将资源分为循环资源、非循环资源．及隐性资源。并结合变迁的个数和激活方式给出了从一个已知的Petri网构造其相应的Stateflow的具体规则．及详细步骤,最后结合某汽车冲压单元的建模进行举例说明。构造过程显示出文中提出的仿真方法具有使用简单、通用性强、扩展性好的特点。     

Graphical simulation of Petri Nets

An interactive graphics package for modeling with Petri Nets has been implemented. It uses the VT-11 graphics terminal supported on the PDP-11/35 computer to draw, execute, analyze, edit and redraw a Petri Net. Each of the above mentioned tasks can be performed by selecting appropriate items from a menu displayed on the screen. Petri Nets with a reasonably large number of nodes can be created and analyzed using this package. The number of nodes supported may be increased by making simple changes in the program. Being interactive, the program seeks information from the user after displaying appropriate messages on the terminal. After completing the Petri Net, it may be executed step by step and the changes in the number of tokens may be observed on the screen, at each place. Some properties of Petri Nets like safety, boundedness, conservation and redundancy can be checked using this package. This package can be used very effectively for modeling asynchronous (concurrent) systems with Petri Nets and simulating the model by “graphical execution.”     

UML模型到面向对象Petri网模型的映射

文章通过分析UML模型和面向对象Petri网各自的特点,提出了UML模型到面向对象Petri网模型的映射规则,从而实现了利用UML模型有效描述系统,利用面向对象Petri网模型模拟仿真系统的有效结合,实现了两者的优势互补.     

Petri网及其扩展研究

Petri网是一种应用非常广泛的建模工具。首先给出了基本Petri网的概念,在此基础上对多种Petri网进行了广泛的研究,包括时间因素Petri网、有色Petri网、面向对象Petri网、模糊Petri网及受控Petri网,并针对每种Petri网的特点和应用范围进行了讨论,提出了Petri网当前发展的方向和急需解决的热点问题。     

Weighted fuzzy reasoning using weighted fuzzy Petri nets

This paper presents a Weighted Fuzzy Petri Net model (WFPN) and proposes a weighted fuzzy reasoning algorithm for rule-based systems based on Weighted Fuzzy Petri Nets. The fuzzy production rules in the knowledge base of a rule-based system are modeled by Weighted Fuzzy Petri Nets, where the truth values of the propositions appearing in the fuzzy production rules and the certainty factors of the rules are represented by fuzzy numbers. Furthermore, the weights of the propositions appearing in the rules are also represented by fuzzy numbers. The proposed weighted fuzzy reasoning algorithm can allow the rule-based systems to perform fuzzy reasoning in a more flexible and more intelligent manner     

计算高级Petri网S-不变量的一种简单算法

在高级Petri网的性质分析中,S—不变量的方法是一个重要的方法,如何计算高级Petri网的S—不变量是一个重要课题。本文基于复合标志(Token)和标志流路的概念,给出了一个整系数线性方程系统,由该线性方程系统,可以得到高级Petri网的所有S—不变量,而不必将高级Petri网扩展为一般Petri网。     

基于Petri网和B语言集成的形式化方法

本文中提出了一种能够描述分布式系统和实时系统的形式化方法-Petri-B 网，Petri-B 网是集成了 Petri 网理论 和 B 语言的形式化方法，它不仅具有了 Petri 网的特点，还具备了 B 语言的长处。本文定义了 Petri-B 网并用它来描述一个座位预 订系统。     

一种面向对象Petri网模型的语义和行为分析

面向对象Petri网根据面向对象思想的特点,对基本Petri网进行了扩展,引入了门、位置类型函数、多态迁移、聚集迁移以及禁止弧等概念.本文介绍了一种面向对象Petri网模型（Object-Oriented Petri Net,OOPN）,给出了OOPN的基本定义和图形表示,并对OOPN进行了语义与行为分析.OOPN能够成为面向对象系统的一种形式化的建模工具.     

一种随机着色Petri网及模型的性能分析

针对随机Petri网（SPN）在系统性能分析时,其状态空间随着系统规模增大而指数性增长,造成求解稳定状态概率的复杂性的不足,提出了一种随机着色Petri网（SCPN）。分析了它的有界性和可达性,证明了它同构于一个一维连续时间的马尔可夫链;同时,也分析了随机着色Petri网用于建模和系统性能定量分析的方法。