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为使模糊Petri网能够描述可变模糊隶属判据下的模糊知识,利用基准变换能较好地表达模糊隶属判据可变情况的特点,基于定性映射和定性基准变换对模糊Petri网进行了扩展,给出了扩展后网模型的形式定义和基本运行机制。通过利用定性映射描述模糊产生式规则,给出了一种新的知识表示模式和推理方法,新方法有利于构建模糊Petri网基于认知的学习机制。结果显示,该网模型具有较强的知识表达能力,适用于处理认知模糊不确定性知识,其推理过程能体现某些认知特性,尤其适用于构建以定性判断为特点的智能系统。 相似文献
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基于Petri网的工作流过程模型及资源分布分析 总被引:1,自引:0,他引:1
针对工作流系统的特点对时延Petri网模型进行扩展,提出了一种新的工作流建模方法,即扩展时延Petri网。给出了扩展时延Petri网的定义,并用该方法分析了工作流四种基本模型;给出了利用排队论和随机Petri网理论计算工作流模型时间性能指标的新方法,用这种方法可求得与实例到达率相关的工作流模型平均完成时间。最后应用上述方法讨论了工作流资源分布的几种模式,并与模拟结果加以对比,计算结果的最大误差在3%左右,说明基于扩展时延Petri网的方法是分析工作流系统时间性能的有效方法。 相似文献
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一种扩展了价格信息的Petri网 总被引:1,自引:0,他引:1
提出一种扩展了价格信息的Petri网——价格Petri网,讨论了相应的分析方法和应用前景。主要工作是:为Petri网的变迁引入价格参数,并用价格变迁系统给出价格Petri网的语义;对价格Petri网进行了可达性分析并讨论了最小成本可达问题的可判定性;最后用价格Petri网建立一个业务流程的成本模型。结论是:为Petri网扩展价 相似文献
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一种扩展了价格信息的时间Petri网 总被引:11,自引:0,他引:11
性能和成本分析是业务流程建模的主要目的,扩展了时间信息的Petri网能够有效地进行性能分析,但是对成本分析却无能为力.提出一种扩展了价格信息的时间Petri网--价格时间Petri网.首先为时间变迁扩展价格参数,并使用价格时间变迁系统给出价格时间Petri网的语义;然后提出计价状态类的概念,并证明为状态类扩展累积成本的合理性和完备性;进而给出一种算法来证明有界价格时间Petri网的最小成本可达问题是可判定的;最后给出一个应用例子并得出结论:为时间Petri网扩展价格信息并将其应用于业务流程管理领域是可行的. 相似文献
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基于带抑止弧时间Petri网的IEEE802.2LLC3型协议的建模 总被引:3,自引:0,他引:3
该文定义了一种扩展的时间Petri网———带抑止弧的时间Petri网,这类扩展的时间Petri网可以用作网络协议描述的工具。作为一个例子,笔者在对IEEE802.2LLC3型协议做简单分析的基础上,给出了一个基于带抑止弧时间Petri网的IEEE802.2LLC3型协议的形式描述。 相似文献
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文中提出了具有人工智能的Petri网模型,并以最短路径问题为例说明了这种智能的Petri网的实用性,扩展了传统Petri网的应用范畴. 相似文献
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蒋昌俊 《中国科学F辑(英文版)》2001,44(3):226-233
As far as we know, the testing problem of legal firing sequence is NP-complete for gener-al Petri net, the related results of this problem on the polynomial-time solvability are limited only to some special net classes, such as persistent Petri nets, conflict-free Petri nets and state machine Petri nets. In this paper, the language properties of synchronous composition net are discussed. Based on these results, the testing algorithm polynomial-time complexity for legal firing sequence is proposed. Therefore, net classification of polynomial-time solvability for testing legal firing sequence is extended. 相似文献
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Tamas Kis Dimitris Kiritsis Paul Xirouchakis Klaus-Peter Neuendorf 《Journal of Intelligent Manufacturing》2000,11(2):191-207
In this paper a new Petri net class (Chameleon systems) for modeling and analyzing joined process planning and job shop production planning is proposed based on the multi-level Petri net model introduced by Valk (1995). Chameleon system is a High-level Petri net extended with time that consists of a High-level Petri net modeling the workshop which is called system net and ordinary Petri net modeling the jobs and setups which act as tokens of the system net and therefore are called token nets. Process plans of the jobs are partial orders of operation groups and alternatives. The uncertainty of operation duration is captured by a new time model. The advantages of this new modeling approach are the following: (i) a modular construction of the joined process and job shop planning is allowed, (ii) classical known Petri net analysis methods can be applied and (iii) the analysis can be done at different levels of abstraction. 相似文献
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工作流过程定义中的分层结构与正则Petri网 总被引:1,自引:0,他引:1
The abstract level problem and the classification of the abstract level problem in the workflow process model are discussed. The formalized problem of the abstract level problem in the process model is researched. The concept and definition of the petri net with end-transition and normal petri net according to the control abstract level problem are put forward and discussed. The equivalence of general Petri Net and general Petri Net is proved by the petri net with priori relationship. 相似文献
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This note discusses the use of Petri net languages in supervisory control theory. First it is shown that the trimming of an unbounded Petri net is not always possible and a new class of Petri net languages, that may be generated by nonblocking nets, is defined. Secondly, necessary and sufficient conditions for the existence of a Petri net supervisor, under the hypothesis that the system's behavior and the legal behavior are both Petri net languages, are derived. Finally, by means of an example, it is shown that Petri net languages are not closed under the supremal controllable sublanguage operator 相似文献
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Chao D.Y. Wang D.T. 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》1997,27(6):962-977
We present two aspects of knitting technique, the structural properties (especially the P- and T-invariants), and the synchronized choice net (a new class of Petri net), that are of both theoretical importance and practical uses to the verification of structural correctness of a Petri net or to detect the structural problem of a Petri net. This work first proves that the ordinary Petri nets synthesized with knitting technique are structurally bounded, consistent, conservative and safe (when each home place holds one token) using the well-known linear algebra approach. It also provides a procedure for finding P- and T-invariants for Petri net synthesized using the knitting technique. We present examples for P-invariants and show that we can synthesize Petri nets more general than the "asymmetric-choice nets". The algorithm for finding P-invariants of ordinary Petri nets is extended to find the P-invariants for a general Petri net synthesized with knitting technique and the arc-ratio rules. We present a new class of Petri nets, called synchronized choice nets, which are the largest set of Petri nets that can be covered by both T-components and P-components. An algorithm is proposed to find its T-components and the P-components, respectively. The complexity of this algorithm is also presented. The theory of synchronized choice nets has the potential to simplify that for free choice nets. 相似文献
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Petri网的组合积网及性能分析 总被引:2,自引:0,他引:2
李孝忠 《小型微型计算机系统》2002,23(1):98-100
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 相似文献