Queueing Petri nets with product form solution

The product form results recently published for stochastic Petri nets are combined with the well-known product form results for queueing networks in the model formalism of queueing Petri nets yielding the class of product form queueing Petri nets. This model class includes stochastic Petri nets with product form solution and BCMP queueing networks as special cases. We introduce an arrival theorem for the model class and present an exact aggregation approach extending known approaches from queueing networks.     

随机Petri网性能等价化简与分析方法研究

随机Petri网等价性能化简技术的研究一直是Petri网研究的主要问题之一,已有学者研究了在指数分布的假设下的随机Petri网的等价化简方法。该文研究指出关于顺序结构、选择结构和循环结构的化简结果并不依赖于指数分布,但是关于并发结构的结果依赖于指数分布。并给出了在均匀分布条件下的随机Petri网并发结构的化简技术。     

广义随机Petri网在制造系统中的应用

介绍广义随机Petri网,通过把其状态分为隐状态和显状态并消去隐状态,使得计算复杂度降低,并将其应用在一个制造系统模型上,使用禁止弧来消除制造系统的冲突.     

基于随机对象Petri网的柔性制造系统性能分析

为了增强传统对象Petri网的定量分析能力,提出随机对象Petri网模型。该模型具备随机性和层次特性,获得与随机Petri网的等价关系,从宏观和微观2个层面对系统进行性能分析,并将该模型应用到柔性制造系统中。实验结果表明,该系统保留了面向对象的建模能力,具有较强的定量分析能力。     

Comparison of Hybrid Systems and Fluid Stochastic Petri Nets

Hybrid Systems are modelsof interacting digital and continuous devices with applicationsin the control of aircraft, computers, or modern cars for instance.Concurrently, Fluid Stochastic Petri Nets (FSPNs) have been introducedas an extension of stochastic Petri nets to model physical systemsthat contain continuous fluid quantities controlled by discretelogic, as well as a means to deal with the possible state explosionof discrete models. Of course, an FSPN is by definition a hybridsystem but in this paper, we compare a general hybrid systemsformalism with FSPN formalism. The conclusion of this paper,suplemented by some examples, is that fluid stochastic Petrinets and hybrid system formalism can be converted from one tothe other. Although there is a price to pay for such a conversion,the conversion can transfer the solution methods from one tothe other and thus help the development of both formalisms.     

基于随机时间Petri网的安全性分析方法

在分析了现有的Petri网与安全性结合的方法的缺陷后,提出了一种基于随机时间Petri网(stochastic Time Petri Nets,sTPN)的系统安全性分析方法,利用sTPN建立的系统模型不局限于指数分布和确定分布的变迁,也不局限于一般分布的变迁的使能限制。通过修改后的瞬态随机状态类图以及sTPN的瞬态分析算法可以得到基于路径的安全性指标。最后给出核反应堆冷却循环系统的例子,说明了所提方法的可用性和合理性。     

时间Petri网的随机模拟

模拟是Peri网进行系统分析的常用方法之一。由于时间Petri网采用时间区间来描述变迁实施的时间范围,因此变迁的实施时间点在区间内是不确定的。提出了时间Petri网的随机模拟方法。该方法在变迁开始使能时,根据某种随机分布确定实施区间内的实施时间点;然后基于模拟仿真的实验数据,运用统计分析方法及算法,构造时间Petri网状态类树,计算变迁实施区间及实施概率,为时间Petri网的系统模拟提供了一种新的探索途径。     

准自相似业务流的SPN模型及其评价

该文研究了近似自相似业务的马尔可夫模型,提出了该模型的相位型表达式并据此将模型从离散时间域转换到连续时间域,笔者对一个处理自相似业务到达的简单队列系统进行了研究,比较了系统在实际跟踪的仿真情况下和模型数值分析情况下的性能,模型数值分析用无穷状态随机Petri网实现,研究表明:马尔可夫模型虽能较好地近似自相似性,但仍需进行改进。     

一种紧同步随机Petri网模型的性能分析方法

紧同步随机Petri网模型常用于对多个子系统构成的实际系统进行建模.由于状态空间爆炸问题,这种模型的性能分析目前还没有得到很好的解决.首先给出了随机Petri网中顺序、并行、循环、选择这4种基本结构的性能近似等价公式,然后提出了一种同步变迁等价分解(synchronous transition equivalent decomposition,简称STED)法对紧同步随机Petri网进行分解求解,有效地缓解了具有一个或多个同步变迁情况下的空间爆炸问题,该方法对于子模型同构的情况处理简便且十分有效.     

Design of Regulatory Traffic Light Control Systems with Synchronized Timed Petri Nets

Fixing the phases is one of the common methods to control an urban traffic network. Once a road is filled with a high traffic flow approaching its capacity, the conventional traffic light controller is not able to handle this traffic congestion phenomenon well. In this paper, we propose a novel regulatory traffic light control system to handle such traffic congestion by using synchronized timed Petri nets (STPNs). Three kinds of intersections in an urban traffic network are defined and employed to demonstrate our new regulatory traffic light control system models. Finally, the liveness and reversibility of the proposed STPN models are proven through the reachability graph analysis method. To our knowledge, this is the first work that solves a traffic congestion problem with a regulatory traffic light control technique that is effective in preventing vehicles from entering traffic congestion zones.     

排队系统的着色Petri网建模与分析

着色Petri网（CPN）是研究离散事件动态系统的有力工具,将着色Petri网引入排队系统建模中,能弥补排队模型缺乏动态逻辑行为分析能力的不足。针对排队系统一般模型建立顶层结构模型,并对排队系统的4个要素给出了具体的CPN描述。给出一个具体实例,阐明排队系统的CPN分析法的使用,利用仿真工具CPN-Tools对模型仿真实现,仿真结果与数学模型得出的理论值对比分析,验证了可行性。     

Basic Server Semantics and Performance Monotonicity of Continuous Petri Nets

Continuous Petri nets were introduced as an approximation to deal with the state explosion problem which can appear in discrete event models. When time is introduced, the flow through a fluidified transition can be defined in many ways. The most used in literature are constant and variable speed (David and Alla, Discrete, continuous and hybrid Petri nets, Springer-Verlag, 2005), which can be seen as some kind of finite and infinite server interpretations of the transitions behavior, and derived from stochastic (discrete) Petri nets (Silva and Recalde, Annu Rev Control 28(2):253–266, 2004). In this paper we will compare the results obtained with both relaxations for the broad class of mono-T-semiflow reducible nets, and prove that, under some frequently true conditions, infinite server semantics offers a throughput which is closer to the throughput of the discrete system in steady state. In the second part, it will be proved that the throughput of mono-T-semiflow reducible net systems is monotone with respect to the speed of the transitions and the initial marking of the net.     

基于Petri网的分布式实时嵌入式系统调度的建模

提出了一种基于资源的时间Petri网模型,以便建模分布式实时嵌入式系统中的静态调度,分析系统性能。该模型将处理器资源和通信资源,以及相应的优先级附着到变迁上,从而建模以下的分布式实时嵌入式系统：在单处理器上采用基于固定优先级的抢先式调度,处理器之间的通信采用基于固定优先级的不可抢先式调度。最后分析了该模型的语义、性质以及状态类图的构造方法。     

Petri网方法及其在制造系统研究中的应用

Petri网是描述、分析和控制离散事件动态系统最有效和应用最广泛的方法。本文先对Petri网的基础理论和重要性质加以介绍,然后对其在制造系统研究中的应用进行评述。     

基于Petri网的非相似余度飞控计算机可靠性分析

应用混合Petri网建立故障诊断模型,应用广义随机Petri网建立Boe ing 777非相似余度飞控计算机故障行为模型.描述了非相似余度系统的结构以及故障的产生和传播的动态过程,分析了该系统的可靠度和容错度,并有效地消除了瞬态故障对分析系统可靠性的影响.     

晶圆制造单元的Petri网建模和性能分析

晶圆制造是半导体制造过程中的一个重要环节,晶圆制造单元的性能直接影响晶圆制造的成本。为了有效地分析晶圆制造单元的动态性能,分别对加工设备存在瓶颈和搬运机器人存在瓶颈的两种情况,进行了赋时Petri网建模研究,建立了晶圆制造单元的赋时Petri网模型。在此基础上,进行了稳态生产率分析,同时用实例验证了模型的有效性和实用性。     

非马尔可夫随机Petri网模型的混合状态分析法

讨论具有发射时间任意分布之变迁的随机Petri网的解析问题.定义了随机Petri网的混合状态和混合状态密度,提出混合状态分析法,并给出具有一步转移关系标识下的混合状态密度的递推公式.使非马尔可夫型随机Petri网的分析成为可能.通过算例说明了混合状态分析法在系统性能评估中的应用.     

基于行为表达式的任意随机Petri网的品质分析

提出一种基于行为表达式的品质分析方法,可以做任意分布的有界或无界随机Petri网的品质分析.该方法不仅拓广了分析范围,解决了文献[4]中没有解决的问题,而且不必画出Petri网的可达标识图,使分析过程更为简洁.     

Fluid Stochastic Petri Nets Augmented with Flush-out Arcs: Modelling and Analysis

Fluid(or Hybrid) Petri Nets are Petri net based models with two classesof places: discrete places that carry a natural number of distinctobjects (tokens), and fluid places that hold a positive amountof fluid, represented by a real number. With respect to previousformulations, the FSPN model presented in this paper, is augmentedwith a new primitive, called flush-out arc. A flush-out arc connectsa fluid place to a timed transition, and has the effect of instantaneouslyemptying the fluid place when the transition fires. The paperdiscusses the modeling power of the augmented formalism, andshows how the dynamics of the underlying stochastic process canbe analytically described by a set of integro-differential equations.A procedure is presented to automatically derive the solutionequations from the model specifications. The whole methodologyis illustrated by means of various examples.     

基于混合随机Petri网的一类混合系统的模型及稳定性

混合动态系统是包含离散事件系统（ＤＥＳ）和连续变量系统（ＣＶＳ）的复杂系统。讨论了一类每个离散状态包含一个连续动态系统,且离散事件具有Ｍａｒｋｏｖ链性质的随机混合系统,在提出利用混合随机Ｐｅｔｒｉ网的建模方法的基础上,给出混合均方稳定的概念、稳定性和可镇定条件,最后以一个简单的例子做子说明和仿真。