基于层次实时有色Petri网的实时服务描述研究

Web服务描述与组合是实现面向服务计算的关键,但目前Web服务描述研究对Web服务的实时性与智能性因素考虑不多,不适合用于分布式实时系统中的服务描述。该文首先定义了适合实时服务描述的实时有色Petri网(RTCPN)与层次实时有色Petri网(HRTCPN),然后建立了原子实时服务到RTCPN映射描述模型(AS-RTCPN),对服务组合运算规则进行了详细描述与建模,最后形成了服务组合HRTCPN描述模型的简化算法,并给出了HRTCPN的可达服务图RSG的定义及构建算法,证明了HRTCPN模型的正确性。     

扩展的模糊时间Petri网

网络实时系统对时间和QoS有严格要求.扩展的模糊时间Petri网是一种对网络实时系统进行建模和分析的形式化模型,Petri网数学理论基础能保证并发系统的可靠性和正确性.本文介绍了扩展的模糊时间Petri网的定义,模型检验方法,仿真工具,网精简技术和应用领域,并探讨了进一步研究的方向.     

UML活动图到时间Petri网的映射方法

UML被广泛应用于嵌入式实时系统等领域的建模,而嵌入式实时系统对时间响应的要求非常严格,UML缺乏对系统时间约束的描述和形式化语义。因此,提出了一种结合MARTE与UML带有时间约束的UML活动图模型,并定义相应的映射规则,将该活动图模型映射到时间Petri 网模型,最后通过实例验证了该映射方法的正确性和实用性。     

基于OPNET的CAN总线实时性的仿真与分析

控制器局域网（ CAN）的建模与仿真不仅能对CAN总线性能进行评估,而且能优化CAN总线网络的设计。在研究分析CAN总线通信控制协议的基础上,采用OPNET网络仿真工具,运用网络层次化建模方法,建立CAN总线通信网络模型。通过该仿真模型,分析了CAN总线网络中CAN节点优先级、传输速率、帧信息量以及填充位等因素对CAN总线网络实时性的影响,从而为CAN总线网络的设计与优化提供理论参考。     

CORBA规范的形式化描述及分析

CORBA为构建大规模分布式应用程序提供了一套公共对象服务规范,其规范主要以IDL语言编写,只提供对象的静态行为描述．提出并应用扩展有色Petri网对CORBA对象进行形式化模拟和分析,结果表明扩展有色Pctri网模型不仅能够清楚描述对象的静态行为,同时也能较好地模拟对象分布性和动态行为．     

反射式需求工程过程演化建模

用反射机制为软件系统需求工程过程演化建模,将需求工程过程的开发活动作为反射系统的基层,实现软件系统的功能需求,将软件系统的非功能需求作为反射系统的元层,对需求工程过程的开发活动进行调节、控制,并将非功能需求的性质反射到功能需求.定义了有色Petri网及其范畴,并用有色Petri网范畴描述软件系统非功能需求性质的模拟、保持和反射机制;用有色Petri网建立反射式需求工程过程演化形式化模型,模拟了软件系统需求工程过程中功能需求和非功能需求的迭代、增量、演化,为软件系统需求工程过程演化建模提出了一种新的方法.     

实时系统的DDSPN建模与VHDL描述和仿真

离散时间确定与随机Petri网(DDSPN)是一种优良的实时系统建模与分析工具。本文研究了基于VHDL的DDSPN描述及仿真方法,分析了VHDL在实时系统建模中的特点与优势,并用一个典型实例验证了该方法的有效性。     

列车总线电缆在TCN网络上的测试与分析

本文是针对列车总线电缆MVB/WTB基于IEC 61375轨道电气设备标准,在TCN列车通信网络上的测试进行分析,使现场组装列车操作人员能通过Fluke测试分析仪有效的判断电缆技术参数是否通过,提供合理的指导和理论依据。     

利用CPN分析通信装备战场抢修系统效能

基于有色Petri网理论,运用建模与仿真技术,对通信装备战场抢修系统效能进行了分析;运用CPN-tools对具体实例进行了仿真实现,其运行结果与该抢修系统的统计结果基本一致;证明了有色Petri网理论和仿真工具在本领域运用的可行性和科学性,为战场抢修系统的效能评估探索出了一种新的方法.     

用FPGA实现多功能车厢总线控制器

本文介绍了多功能车厢总线(MVB),分析了国外先进MVB网卡的通信机制与特点,在此基础上,提出了用FPGA技术实现该网卡的核心部分多功能车厢总线控制器(MVBC)的方法,并采用功能相关的模块分组验证方法,对MVBC进行了功能验证及时序验证。     

Modeling, analysis, simulation, scheduling, and control ofsemiconductor manufacturing systems: A Petri net approach

This paper presents a Petri net approach to modeling, analysis, simulation, scheduling, and control of semiconductor manufacturing systems. These systems can be characterized as discrete event systems that exhibit sequential, concurrent, and conflicting relations among the events and operations. Their evolution is dynamic over time. The system complexity is tremendous owing to the complex semiconductor manufacturing processes and test procedures. A formal approach such as Petri nets enables one to describe such complex discrete event systems precisely and thus allows one to perform both qualitative and quantitative analysis, scheduling and discrete-event control of them. This paper also serves as a tutorial paper. It briefly reviews applications of Petri nets in semiconductor manufacturing automation. It then introduces definitions and concepts of Petri nets. It proceeds with a discussion of basic Petri net modules in system modeling, a modeling method and a practical system's modeling example. Next, the paper presents their properties and their implications in manufacturing systems, as well as their analysis methods. Timed Petri nets are introduced for system simulation, performance evaluation, and scheduling purposes. An application-oriented case study is presented. Finally, the paper concludes with the active research areas in applying Petri nets to design of semiconductor manufacturing systems     

有界Petri网等价性的判定算法

Petri网语言是系统行为分析的一种重要工具,为了分析有界Petri网的行为等价,借助于有限自动机的等价性问题和算法,研究了有界Petri网的等价性问题和算法.定义了带标注Petri网语言等价性,证明了带标注的有界Petri网到有限自动机的等价转化,给出了判定有界Petri网的等价性算法,为模拟系统的性能比较提供了处理方法.     

Modeling and simulation of an electronic component manufacturingsystem using hybrid Petri nets

Modelling and analysis for the design and operation of manufacturing systems is a vital need. For semiconductor manufacturing systems, which are large scale systems, discrete Petri nets do not constitute an adequate tool for modeling and analysis. In fact, use of discrete Petri nets is confronted with tile state explosion and the high cost of simulation. In this paper, hybrid Petri nets are presented as powerful tools for modeling and simulation of semiconductor manufacturing systems. This model has been used for modeling and simulation of a real life electronic components manufacturing system. It provides an accurate and first simulation of this system     

基于随机高级Petri网的ATM网络接纳控制过程模型

本文提出了一个ＡＴＭ网络的接纳控制过程模型，此模型是基于随机高级Ｐｅｔｒｉ网的层次模型方法。在复杂的ＡＴＭ网络的接纳控制过程模型中，使用了从顶向下的模型方法。在模型的性能分析中，则采用了从底向上的分解、压缩的方法。这种方法简化了复杂系统模型的状态空间爆炸问题。     

Model-driven software synthesis for hard real-time applications with energy constraints

Model-driven methods have been quite effective for reducing the intricacies of embedded software development, since they provide effective means for property verification as well as automatic code generation. Nevertheless, regarding energy-constrained hard real-time systems, few model-driven methods are available and, usually, most methods (model-driven or not) consider simplified system specifications, such as absence of intertask relations. This paper presents a model-driven method for software synthesis of hard real-time embedded applications with energy constraints. A formal model based on time Petri nets is adopted in order to provide a basis for pre-runtime schedule generation and property analysis/verification.     

Comparing ladder logic diagrams and Petri nets for sequencecontroller design through a discrete manufacturing system

Design methods for sequence controllers play a very important role in advancing industrial automation. The increasing complexity and varying needs of modern discrete manufacturing systems have challenged the traditional design methods such as the use of ladder logic diagrams (LLDs) for programmable logic controllers. The methodologies based on research results in computer science have recently received growing attention by academic researchers and industrial engineers in order to design flexible, reusable, and maintainable control software. Particularly, Petri nets are emerging as a very important tool to provide an integrated solution for modeling, analysis, simulation, and control of industrial automated systems. This paper identifies certain criteria to compare LLDs and Petri nets in designing sequence controllers and responding to the changing control requirements. The comparison is performed through a practical system after introducing “real-time Petri nets” for discrete-event control purposes. The results reported in this paper will help: (a) further establish Petri net based techniques for discrete-event control of industrial automated systems; and (b) effectively convince industrial practitioners and researchers that it is worthy and timely to consider and promote the applications of Petri nets to their particular discrete-event control problems     

基于FPGA的有色Petri网仿真系统设计

为了实现大规模有色Petri网模型的性能测试,设计了基于FPGA的高速仿真系统。该系统实现了库所、变迁模块到硬件结构的映射,采用C语言实现了有色Petri网的硬件自动生成工具。通过分析有色Petri网的特征,该工具生成对应的Verilog代码和基于Quartus的自动脚本。以通信中"包传输"的模型为例,在FPGA中对生成的代码进行测试,验证了设计的正确性。     

Petri nets: Properties, analysis and applications

Starts with a brief review of the history and the application areas considered in the literature. The author then proceeds with introductory modeling examples, behavioral and structural properties, three methods of analysis, subclasses of Petri nets and their analysis. In particular, one section is devoted to marked graphs, the concurrent system model most amenable to analysis. Introductory discussions on stochastic nets with their application to performance modeling, and on high-level nets with their application to logic programming, are provided. Also included are recent results on reachability criteria. Suggestions are provided for further reading on many subject areas of Petri nets     

Structuring and composability issues in Petri nets modeling

Along Petri nets' history, numerous approaches have been proposed that try to manage model size through the introduction of structuring mechanisms allowing hierarchical representations and model composability. This paper proposes a classification system for Petri nets' structuring mechanisms and discusses each one of them. These include node fusion, node vectors, high-level nets, and object-oriented inspired Petri nets extensions, among others. One running example is used emphasizing the application of the presented mechanisms to specific areas, namely to automation systems modeling, and software engineering, where object-oriented modeling plays a major role.