基于Petri网的半导体生产线建模

总结了Petri网在半导体生产线建模中的应用,着重针对半导体生产线大规模,可重入,可靠性,混合加工方式,不确定性等特殊复杂性,对多种扩展Petri网模型进行了分析和比较,并进一步探讨了基于Petri网模型和扩展Petri网模型的半导体生产线建模方式,指出了存在的问题,并探讨了可能的研究方向。     

基于面向对象Petri网的工作流建模及性能分析

工作流技术作为一种过程建模和过程管理的核心技术，在计算机应用领域获得了迅速的发展。介绍了工作流技术；提出了将面向对象建模技术融入Petri网模型所形成的面向对象Petri网，并讨论了建立基于面向对象Petri网的工作流模型的步骤；运用面向对象Petri网建立了某制造企业的产品方案处理流程的工作流模型，并运用性能等价公式对工作流模型的性能进行了分析。     

军用装备维修保障系统面向对象Petri网建模

Petri网模型是离散事件动态系统(DEDS)建模的有利工具,但传统的Petri网模型存在模型结构复杂、缺少时间描述等不足。该文在装备维修保障系统建模中,结合应用面向对象技术和有色Petri网、赋时Petri网理论,提出了将面向对象思想与赋时Petri网相结合进行装备维修保障系统建模的方法,并应用该方法对已有的空军通信导航装备维修保障系统Petri网模型进行了对象化和赋时改造,使得新建模型结构更加简约、直观,有利于扩展和仿真实现,并且具备时间描述功能。     

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。     

面向对象的Petri网建模技术的研究

将面向对象的概念引入到Petri网建模技术中，对网进行分类与抽象，给对象模型的消息和方法赋予新的含义，并将Petri网扩展成具有输入与输出的开放式系统，从而形成了面向对象的Petri网建模技术（简称OPNe技术）。给出的OPNet建模技术的一般方法具有较大的实际意义。     

基于面向对象Petri网的工作流建模及性能分析

工作流技术作为一种过程建模和过程管理的核心技术,在计算机应用领域获得了迅速的发展。介绍了工作流技术;提出了将面向对象建模技术融入Petri网模型所形成的面向对象Petri网,并讨论了建立基于面向对象Petri网的工作流模型的步骤;运用面向对象Petri网建立了某制造企业的产品方案处理流程的工作流模型,并运用性能等价公式对工作流模型的性能进行了分析。     

神光Ⅲ控制系统的故障建模与分析

应用混合随机Petri网对神光Ⅲ控制系统的故障进行了建模，并应用Visobj Net对建立的故障模型进行了仿真分析。网络化控制系统是一个离散和连续相结合的混合动态系统，具有动态、并发及同步等特征；神光Ⅲ控制系统就是网络化控制技术在武器装备上的一个典型应用；对于复杂系统的建模和分析，Petri网是一个非常有效的工具。Petri网已经被证明是离散事件或异步系统很好的建模和分析工具，混合随机Petri网是Petri网的一个扩展，具有强大的建模功能。仿真结果表明，所建立的模型是正确的。     

面向对象Petri网继承性的研究

面向对象Petri网(OOPN)利用面向对象的封装性解决了Petri网不能用于大型系统建模的问题.针对大型系统建模中的面向对象Petri网建模的便捷性进行研究,将面向对象的继承性以及与之紧密联系的多态性引入到OOPN中,以其在更大程度上实现模型的复用,使大型系统建模过程更加便捷、灵活.     

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.     

随机Petri网可视化软件的设计与实现

针对随机Petri网建模设计与分析的复杂性问题,通过面向对象方法在VisualC++环境下利用MFC开发了可视化的随机Petri网建模和分析工具SPNSim。利用广度优先思想,设计了可达图的生成算法,给出了随机Petri网模型的编辑器,用户可以直观方便地进行随机Petri网编辑,同时还能进行模型分析,得到可达图、稳态概率等随机Petri网特性和系统性能指标。通过对一个实例的建模与分析,结果验证了软件工具SPNSim的正确性和可用性。     

资源配置混杂Petri网的混杂系统生产过程动态调度

为了增强混杂生产过程应对突发事件的能力,以一种新的混杂Petri网(资源配置混杂Petri网)为研究模型,给出了相应的使能和激发规则.并在资源配置混杂Petri网建立的仿真模型的基础上,融入事件逻辑网和逻辑规划,提出一种适用于混杂系统动态生产调度建模和优化的方法.以典型的混杂生产过程为例,研究混杂系统生产过程建模及优化.研究结果表明,资源配置混杂Petri网模型描述能力强,能够有效描述混杂系统生产过程,所提出的动态调度方案切实有效.     

Software modeling and analysis using a hierarchical object-oriented Petri net

Petri net is used widely to analyze and model various systems formally. Recently, many Petri nets mania devote their efforts to enhancing and extending the expressive power of Petri nets. One such effort is to extend Petri nets with object-oriented concepts. An object-oriented paradigm provides excellent concepts to model real-world problems. Object-oriented concepts allow us to build software systems easily, intuitively, and naturally. Although several high-level Petri nets with the concept of objects are suggested, these nets do not fully support the object-oriented concepts. In this paper, we propose a hierarchical object-oriented Petri net (HOONet). The formal syntax and semantics of HOONet are explained in detail. HOONet supports a wide range of object-oriented features including abstract, encapsulated and modularized objects, object interaction by message passing, inheritance, and ploymorphism. HOONet also supports a variety of modeling and analysis mechanisms such as incremental modeling of evolving systems, unfolding the HOONet to lower level Petri net, and incremental reachability analysis for HOONet models. We demonstrate the usefulness of HOONet by applying it to modeling and analysis with an example.     

基于扩展混成Petri网的CPS无人车系统建模与分析

信息物理融合系统(Cyber-Physical System,CPS)是一个集计算系统、通信系统、感知系统、控制系统和物理系统于一体的复杂系统,其行为是一种由离散计算过程与连续物理过程深度融合并紧密交互的混成行为。针对这种特性,采用混成Petri网对CPS建模,并在此基础上添加时间约束,即对离散变迁关联一个延迟时间,对连续变迁关联一个激发速率函数,同时引入抑止弧和测试弧的概念以提高Petri网的表达能力,由此提出一种新的模型——扩展混成Petri网模型。然后,对CPS应用中无人驾驶车辆系统的躲避障碍物场景进行建模,将建立的模型按照一定的规则转化为与之对应的Simulink模型,并通过Matlab仿真对系统行为及属性进行分析。     

具有多品种晶圆混合加工的单臂组合设备调度

为了提高晶圆制造中组合设备的生产效率,在考虑晶圆驻留时间约束条件下,研究没有共享加工模块的多品种晶圆混合加工的单臂组合设备调度问题.首先,采用面向资源的Petri网模型描述多种晶圆产品的混合加工过程,引入控制变迁避免模型的死锁,采用赋时库所和赋时变迁模拟系统资源的活动时间.其次,通过虚拟加工的方法平衡工序的负载,基于系统Petri网模型和拉式调度策略,推导出单臂组合设备在多品种晶圆混合加工情形下的可调度性判定条件,并以解析形式描述.最后,提出了系统稳态调度求解算法并以实例验证了算法的有效性和可行性.     

神光III控制系统的故障建模与分析

应用混合随机Petri网对神光III控制系统的故障进行了建模,并应用Visobj Net对建立的故障模型进行了仿真分析。网络化控制系统是一个离散和连续相结合的混合动态系统,具有动态、并发及同步等特征;神光III控制系统就是网络化控制技术在武器装备上的一个典型应用;对于复杂系统的建模和分析,Petri网是一个非常有效的工具。Petri网已经被证明是离散事件或异步系统很好的建模和分析工具,混合随机Petri网是Petri网的一个扩展,具有强大的建模功能。仿真结果表明,所建立的模型是正确的。     

Schedulability Analysis of Time-Constrained Cluster Tools With Bounded Time Variation by an Extended Petri Net

Cluster tools for some wafer fabrication processes such as low-pressure chemical vapor deposition have strict wafer delay constraints. A wafer that completes processing in a processing chamber should leave the chamber within a specified time limit. Otherwise, the wafer suffers from severe quality troubles due to residual gases and heat within the chamber. An important engineering problem is to verify whether for given task times there exists a tool operation schedule that satisfies the wafer delay limit. There have been studies on the problem, which all assume deterministic task times. However, in reality, the task times are subject to random variation. In this paper, we develop a systematic method of determining schedulability of time-constrained decision-free discrete-event systems, where time variation can be confined within finite intervals. To do this, we propose an extended Petri net for modeling such systems. We then develop a necessary and sufficient condition for which there always exists a feasible schedule and one for which there never exists any feasible schedule. We develop a graph-based computational procedure for verifying the schedulability conditions and determining the worst-case task delay. We demonstrate how the procedure can be used for cluster tool engineering to control wafer delays against wafer alignment failures and time variation.      

A generalized Petri net modeling approach for the control of re-entrant flow semiconductor wafer fabrication

Re-entrant flow manufacturing lines, such as occur in semiconductor wafer fabrication, are characterized by a product routing that consists of multiple visits to a workstation or group of workstations during the manufacturing process. In this paper, a modeling approach is based on the use of generalized Petri nets for a re-entrant flow manufacturing line is presented. Specifically, three Petri net models representing a re-entrant flow line with three work centers and six machines are modeled. How these models may be used to represent a variety of queuing disciplines and work release policies is discussed.     

On Hybrid Petri Nets

Petrinets (PNs) are widely used to model discrete event dynamic systems(computer systems, manufacturing systems, communication systems,etc). Continuous Petri nets (in which the markings are real numbersand the transition firings are continuous) were defined morerecently; such a PN may model a continuous system or approximatea discrete system. A hybrid Petri net can be obtained if onepart is discrete and another part is continuous. This paper isbasically a survey of the work of the authors' team on hybridPNs (definition, properties, modeling). In addition, it containsnew material such as the definition of extended hybrid PNs andseveral applications, explanations and comments about the timingsin Petri nets, more on the conflict resolution in hybrid PNs,and connection between hybrid PNs and hybrid automata. The paperis illustrated by many examples.