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业务流程管理系统存在可以改变系统行为的潜在故障,因此研究定位系统中故障发生的最小结构变化区域是十分必要的,它对提高业务系统的鲁棒性具有重要意义.本文提出了一种日志诱导下的变化挖掘方法,即最小结构故障域识别方法(minimal structure fault region identification,MSFRI),该方法通过系统的行为变化来定位故障发生的结构因果关系.进一步,针对合理的自由选择业务流程Petri网系统,形式化定义了6种典型变化模式,这些变化模式为故障的结构因果关系变化挖掘提供理论基础.本文所提出的故障定位方法通过识别业务流程Petri网系统的行为变化,实现具有最少库所和变迁数目的故障区域定位,有助于实现系统更加复杂的变化挖掘.本文工作的主要创新之处在于从结构因果关系的角度出发,借助系统行为变化挖掘实现定位业务系统中的潜在故障. 相似文献
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由于大型复杂的业务流程模型不便于用户形成快速的梗概理解,因此模型的抽象化简方法研究至关重要.已有的模型抽象化简方法大都考虑模型的控制流,很少考虑模型的交互语义,并且对于模型的待抽象区域定位模糊.本文利用Petri网的行为关系理论,结合深度优先搜索的思想,提出了基于搜索树的业务流程模型抽象化简方法.通过定义工作流网的3种块结构和边界库所的概念,得到网系统的变迁关联搜索树,进而利用变迁关联搜索树来识别模型中待抽象的区域,从而实现模型的抽象化简.最后,通过一个具体的实例来验证所提出方法的有效性和可行性.本文的主要贡献是:在同时考虑模型行为交互语义和控制流依赖关系的基础上,提出块结构的抽象化简方法和块结构的识别定位方法,算法的时间复杂度控制在多项式难度. 相似文献
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基于Petri网的流程模型中最小变化域的分析方法 总被引:2,自引:2,他引:0
为了灵活适应市场业务需求变化,确定业务流程中的变化部分成为业务流程管理的核心问题.已有的研究都是建立在静态的分析基础上,通过给定的变化节点来搜索变化范围,具有一定的局限性.基于Petri网方法及行为轮廓思想对业务流程模型进行分析,从动态行为角度分别给出了寻找流程模型中的行为变化部分的方法,以及确定流程模型中最小变化域的分析方法.并给出一个具体的业务流程的实例,分析了该方法的有效性. 相似文献
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数据竞争是多线程程序的常见漏洞之一,传统的数据竞争分析方法在查全率和准确率方面难以两全,而且所生成检测报告难以定位漏洞的根源.鉴于Petri网在并发系统建模和分析方面具有行为描述精确、分析工具丰富的优点,提出一种基于Petri网展开的新型数据竞争检测方法.首先,对程序的某一运行轨迹进行分析和挖掘,构建程序的一个Petri网模型,它由单一轨迹挖掘得到,却可隐含程序的多个不同运行轨迹,由此可在保证效率的同时降低传统动态分析方法的漏报率;其次,提出基于Petri网展开的潜在数据竞争检测方法,相比静态分析方法在有效性上有较大提升,而且能明确给出数据竞争的产生路径;最后,对上一阶段检测到的潜在数据竞争,给出基于CalFuzzer平台的潜在死锁重演调度方法,可剔除误报,保证数据竞争检测结果的真实性.开发相应的原型系统,结合公开的程序实例验证了所提方法的有效性. 相似文献
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《计算机科学与探索》2016,(4):516-523
在业务流程管理中,确定流程模型的最小变化域是一项重要的问题。已有的方法主要是从整个模型的角度去分析考察它的最小变化域,计算量比较复杂,具有一定的局限性。为了尽快查找到目标模型中的最小变化域,提出了Petri网动态切片的方法。首先通过对比分析源模型和目标模型的结构图得出目标模型的可疑区域,接着依据行为轮廓的思想在目标模型可疑区域中搜索出变化域,然后通过Petri网动态切片的方法得到目标模型的最小变化域。最后通过具体的电子购物实例,验证了该方法的有效性。 相似文献
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基于Petri网的Web服务BPEL4WS建模与分析 总被引:6,自引:0,他引:6
描述了Web服务业务流程执行语言(BPEL4WS或BPEL)的Petri网建模方法,利用网结构描述基于Web服务业务流程的行为特性。在对BPEL4WS的结构性活动和故障补偿处理机制进行逐层分析的基础上,提出了一个利用Petri网的逐步求精技术对流程进行建模的算法。然后结合具体实例阐述了利用该算法建模的详细过程,并对所生成的Petri网模型进行了完整性(soundness)验证 相似文献
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提出了一种用于可重构制造单元故障恢复的策略与方法, 允许故障发生时, 通过对用于正常操作控制的Petri网形式的监督控制器进行局部、临时性的修改, 实现故障的恢复. 首先, 提出改进的网重写系统, 可用于动态改变Petri网模型结构. 然后,提出了基于改进的网重写系统的故障恢复方法, 其中改进的网重写系统用于操作、引导Petri网监督控制器由错误状态进入正确状态. 故障恢复后监督控制器的结构与期望属性维持不变. 最后, 以实例演示了该故障恢复方法的应用, 证实了方法的有效性. 相似文献
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In this note, we develop algebraic approaches for fault identification in discrete-event systems that are described by Petri nets. We consider faults in both Petri net transitions and places, and assume that system events are not directly observable but that the system state is periodically observable. The particular methodology we explore incorporates redundancy into a given Petri net in a way that enables fault detection and identification to be performed efficiently using algebraic decoding techniques. The guiding principle in adding redundancy is to keep the number of additional Petri net places small while retaining enough information to be able to systematically detect and identify faults when the system state becomes available. The end result is a redundant Petri net embedding that uses 2k additional places and enables the simultaneous identification of 2k-1 transition faults and k place faults (that may occur at various instants during the operation of the Petri net). The proposed identification scheme has worst-case complexity of O(k(m+n)) operations where m and n are respectively the number of transitions and places in the given Petri net. 相似文献
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Lingxi Li Hadjicostis C.N. Sreenivas R.S. 《IEEE transactions on systems, man, and cybernetics. Part A, Systems and humans : a publication of the IEEE Systems, Man, and Cybernetics Society》2008,38(1):207-217
This paper proposes an approach for providing tolerance against faults that may compromise the functionality of a given controller modeled by a Petri net. The method is based on embedding the given Petri net controller into a larger (redundant) Petri net controller that retains the original functionality and properties, and uses additional places, connections, and tokens to impose invariant conditions that allow the systematic detection and identification of faults via linear parity checks. In particular, this paper considers two types of redundant Petri net controllers: 1) nonseparate redundant Petri net controllers have the same functionality as the given Petri net controller and allow for fault detection and identification, but do not necessarily retain the given controller intact; and 2) separate redundant Petri net controllers are a special case of the nonseparate redundant controllers that retain the given Petri net controller intact but enhance it with additional places to enable fault detection and identification. The work in this paper obtains complete characterizations of both types of redundant controllers along with necessary and sufficient conditions for them to be bisimulation equivalent to the given original Petri net controller. In addition, this paper discusses how each type of redundant controllers can be designed to have desirable fault detection and identification capabilities. When the bisimulation equivalence requirement is not directly enforced, nonseparate redundant controllers can potentially have advantages over separate ones (e.g., they can use fewer connections to detect and identify the same number of faults). An example of a Petri net controller for a production cell and its fault tolerance capabilities using separate and nonseparate embeddings is used to illustrate the approach. 相似文献
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针对当前地铁车辆故障,特别是电气故障判断的自动化需求,结合Petri网故障树判断方法,对某型号的地铁车辆故障进行判断。先对Petri网进行简单的概述,然后构建电气系统的Petri网模型,并定义相关的规则,最后搭建Petri网模型验证平台,对上述的地铁车辆传动系统故障进行判断,结果通过地面服务器展示出来。 相似文献
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Ming Yu Danwei Wang Ming Luo Danhong Zhang Qijun Chen 《Expert systems with applications》2012,39(11):9955-9965
This article presents a solution to the problem of multiple fault detection, isolation and identification for hybrid systems without information on mode change and fault patterns. Multiple faults of different patterns are considered in a complex hybrid system and these faults can happen either in a detectable mode or in a non-detectable mode. A method for multiple fault isolation is introduced for situation of lacking information on fault pattern and mode change. The nature of faults in a monitored system can be classified as abrupt faults and incipient faults. Under abrupt fault assumption, i.e. constant values for fault parameters, fault identification is inappropriate to handle cases related to incipient fault. Without information on fault nature, it is difficult to achieve fault estimation. Situation is further complicated when mode change is unknown after fault occurrence. In this work, fault pattern is represented by a binary vector to reduce computational complexity of fault identification. Mode change is parameterized as a discontinuous function. Based on these new representations, a multiple hybrid differential evolution algorithm is developed to identify fault pattern vector, abrupt fault parameter/incipient fault dynamic coefficient, and mode change indexes. Simulation and experiment results are reported to validate the proposed method. 相似文献
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针对复杂系统故障传播和故障分析的模糊性和不确定性,首先,在逻辑Petri网和模糊Petri网的理论基础上,根据逻辑Petri网的传值不确定性以及模糊Petri网对模糊信息的表示和推理能力的特点,提出模糊逻辑Petri网的概念及推理规则,考虑不同故障源对故障的影响程度,将概率信息引入模糊逻辑Petri网,对故障源赋予置信度,使故障诊断过程更符合实际。其次,利用模糊逻辑Petri网对故障诊断系统进行建模,用模糊逻辑Petri网描述了系统故障状态组合的逻辑关系,并进一步简化了系统模型的表达形式,具有良好的封装性、重构性和可维护性,在一定程度上缓解了状态组合空间爆炸问题。针对故障的传播性,采用可达性分析方法对故障信息的传播路径进行模拟论证,提高了故障诊断效率。最后,通过离心式压缩机故障诊断过程实例分析,验证了该方法的有效性和可行性,提高了故障诊断过程的准确性和高效性。 相似文献
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时间因素在对实时系统的分析中占据着重要的位置。随着时间因素在Petri网应用分析中的地位越发重要,各种与时间相关的Petri网模型相继被提出。文中结合动态实时系统的运行特征,设计了一种变迁点火时间服从正态分布的随机Petri网模型,并基于对系统行为的统计分析,提出了一种用于对变迁时间参数进行识别的数值算法。以一种随机制造单元为例,建立正态随机Petri网模型,并运用参数识别算法确定变迁时间参数。仿真结果符合系统的实际运行结果,证明了该方法的有效性。 相似文献
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This paper presents a methodology for diagnosing faults of controllers which are modeled by Petri nets with uncontrollable and unobservable transitions. The inadmissible constraints with uncontrollable and unobservable transitions are transformed into admissible conditions in this method. And we can design controllers easily using reduction technique. In order to provide tolerance against faults in controllers, we embed the given Petri net controller into a larger Petri net controller that retains the functionality of original controllers, and encode the large Petri net controller. Separate redundant Petri net controllers using additional places, connections and tokens to impose invariant conditions allow the systematic detection and identification of faults via Hamming code. The proposed method is attractive because it can check faults (place faults, transition faults or mixed faults) easily. A manufacturing cell is taken as an example to illustrate the approach. 相似文献
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新型Petri网故障诊断算法研究 总被引:4,自引:0,他引:4
Petri网是一种高效的离散事件动态系统建模工具。该文基于Petri网的基本原理,结合故障诊断问题的特点,对petri网在故障诊断中的应用进行了研究,提出了新型Petri网故障诊断算法。并以多轴机床为例建立了Petri网故障模型,分析了故障传播的机理,验证了该算法的有效性。 相似文献