基于模糊Petri网的引航员作业舒适度评价

为提高引航员的作业舒适度,提出一种基于模糊Petri网(FPN)的模糊推理算法(FRA)下的组合评价方法。首先,针对作业舒适度影响因子的不确定性信息,建立多因素耦合的FPN拓扑结构;然后,采用博弈论组合赋权法确定最优组合权重,提出融合层间相关性判断临界重要性、层次分析法和FRA,建立基于主客观权重的FRA,通过迭代求解库所可信度和状态矩阵;最后,结合上海港船舶引航的场景数据,基于FPN的FRA应用,评价引航员作业舒适度。结果表明:环境与引航设备是影响其作业舒适度的关键因素,冬季和夏季的引航作业舒适度评价等级对应“较不舒适”,其中,5月份为“较舒适”。所提方法充分体现系统舒适度影响因素的耦合特性。

一种分层模糊Petri网风险评估方法

针对传统模糊Petri网在对不确定环境下的专家系统的知识表示与推理时无法兼顾不确定知识的模糊性与随机性、在复杂的故障情况下故障的因果关系表达不清晰、定量推理计算时缺乏层次性、不能局部求解的问题,构建一种基于云模型的分层模糊Petri网以加强模糊Petri网的知识表示能力和提高推理过程的计算效率。利用专家知识和Petri网层次分解原则将系统故障模式和故障原因之间的因果关系进行建模,使故障建模更具结构性,计算更加灵活;应用云模型处理知识的模糊性和不确定性;通过合理考虑局部权重和全局权重,结合Petri网层次分解原则和云聚合算子给出相应的推理算法。实例验证表明,所提方法能够有效对系统进行风险评估,且在知识表示和推理方面优于其他方法。

基于毕达哥拉斯模糊概率Petri网的FPSO单点关键部件风险评估

为准确对FPSO单点系泊系统关键部件进行风险评估,通过产生式规则建立概率Petri网络模型,基于德尔菲法的结构熵权法确定专家权重,并引入毕达哥拉斯模糊集理论收集、聚合专家意见得到基本事件的模糊可能性得分和模糊失效概率,利用概率推理算法迭代出最终的失效概率,并进行基本事件重要度分析。实例分析结果表明,引起单点系泊系统发生失效的主要因素有电滑环电刷磨损、电滑环负载电流较高、液滑环结构物晃动冲击、液滑环润滑不充分、电滑环电压过高击穿等。针对主要风险因素提出预防和控制措施,能够保障系统安全正常地运转。

融合PSO-模糊Petri网的室内燃气泄漏风险研究

近年来室内燃气事故多发,而燃气用户风险意识淡薄、户内安全检查难度大。针对现行室内燃气安全管理技术多为静态主观评估的局限性,构建了基于模糊Petri网(Fuzzy Petri Net,FPN)的风险计算规则,提出了结合粒子群优化算法(Particles Swarm Optimization,PSO)和FPN的室内燃气泄漏动态风险评估模型。首先,应用Petri网的直观图像描述和异步并发处理能力建立室内燃气泄漏事故风险演化的拓扑结构模型,借助FPN的模糊推理能力处理风险传播的不确定性;然后,根据燃气运维数据,融合PSO动态更新初始参数,提高风险评估的准确性。结果表明,基于PSO-FPN的室内风险评估方法可弱化燃气公司安检人员分析的主观不确定性,更为准确地量化风险因子演化过程,实现室内燃气泄漏风险的动态分析,有效支持户内燃气泄漏风险管控。

基于改进的分层WFPN的电网故障诊断

针对提升电网故障诊断模型准确性和解决因模型元件增减而引起模型构建复杂的问题,提出了基于改进的分层加权模糊Petri网(WFPN)电网故障诊断方法。首先,根据故障元件及故障蔓延方向建立其故障子模型和综合模型两层模型,解决因元件增减而引起模型构建复杂度问题;其次,在主观赋值法的基础上通过优化组合赋值法对输入权值进行优化赋值,使得故障诊断结果具有较高准确性;最后,通过对14节点电力系统进行仿真分析,发现在面临信息不完备及保护或断路器拒动挑战时,WFPN电网故障诊断方法仍能够提供可靠的故障诊断结果,具有较高的容错性。

基于模糊Petri网和马尔科夫链理论的水电厂设备故障应急响应模型

为保证水电厂设备安全,避免因故障导致意外事故,基于模糊Petri网和马尔科夫链理论设计水电厂设备故障应急响应模型。确定加权因子命题阈值,结合传感器收集的初始信号,在滤波器的作用下还原信号特征,基于模糊Petri网提取水电厂设备故障特征。设计故障分类器,建立概率转移矩阵,设置概率转移矩阵的条件,面对动态解码,给定模型参数,计算马尔可夫模型下的连续变量密度函数,修正比例因子的状态系数,得到设备故障分类结果。建立设备故障应急响应模型,输出设备故障状态下的应急响应结果。实验结果显示,该模型在四种故障类型中的分类精度分别为98.8%、98.6%、98.7%、98.8%,可见该模型分类精度较好。

基于Fuzzy Petri网专家系统的研究

提出采用ＦｕｚｚｙＰｅｔｒｉ网作为知识表示和推理机制的模型，发挥其较好的模型描述和能处理并行推理的特点。基于ＦｕｚｙＰｅｔｒｉ网构造了一个耦合结构的专家数据库系统（ＥＤＢＳ），提高了推理的效率及其准确性，同时具有并发控制、数据组织、共享、存取和查询等数据库管理系统的功能，并使用投资决策实例对模型进行了解释和验证。

Designing Genetic Regulatory Networks Using Fuzzy Petri Nets Approach

In this paper, we have successfully presented a fuzzy Petri net （FPN） model to design the genetic regulatory network. Based on the FPN model, an efficient algorithm is proposed to automatically reason about imprecise and fuzzy information. By using the reasoning algorithm for the FPN, we present an alternative approach that is more promising than the fuzzy logic. The proposed FPN approach offers more flexible reasoning capability because it is able to obtain results with fuzzy intervals rather than point values. In this paper, a novel model with a new concept of hidden fuzzy transition （HFT） to design the genetic regulatory network is developed. We have built the FPN model and classified the input data in terms of time point and obtained the output data, so the system can be viewed as the two-input and one output system. This method eliminates possible false predictions from the classical fuzzy model thereby allowing a wider search space for inferring regulatory relationship. The experimental results show the proposed approach is feasible and acceptable to design the genetic regulatory network and investigate the dynamical behaviors of gene network.

基于改进的方向性加权模糊Petri网配电网故障诊断

为提高配电网保护动作信息丢失时故障诊断的准确率及容错性,提出了基于改进的方向性加权模糊Petri网配电网故障诊断方法。首先,考虑故障发生时近后备保护对可疑故障元件故障诊断的影响,对可疑故障元件的各个故障蔓延方向进行建模;其次,在专家经验的基础上采用随机数对模型输入权值进行随机赋值;最后,在保护动作信息丢失时,跟踪改变可疑故障元件保护未动作的可信度取值,并分析该故障诊断方法的适应性与容错性。仿真结果表明,所提基于改进的方向性加权模糊Petri网配电网故障诊断模型在信息不完备或者保护及断路器拒动时,均具有较高的故障诊断准确率。

基于NCM-FPN的古建筑修缮阶段施工安全综合评价

为有效预防古建筑修缮阶段施工安全事故,提出了基于正态云模型(Normal Cloud Model, NCM)与模糊Petri网(Fuzzy Petri Net, FPN)的施工安全综合评价方法。首先,分析古建筑修缮阶段施工特点及风险特性,建立多因素耦合作用下的三脚架事故致因模型(Tripod-Delta),构建指标体系。然后,将指标体系转换为施工安全多因素耦合FPN网络结构,采用NCM确定FPN指标初始状态,通过逆向搜索策略约简FPN冗余指标节点,并运用模糊推理算法与障碍因子诊断模型得出评价结果。结果表明,实例评价结果与现场情况基本一致,协同管理与材料设备是影响古建筑修缮阶段施工安全的关键因素。所提方法能充分表达古建筑修缮阶段施工安全风险的耦合特性,并确定安全管理的关键因素,评价结果客观准确。

基于模糊Petri网的配电变台工程成本偏差指标诊断与预警机制研究

大数据技术在配电网工程管理中的应用越来越广。当下,多数配电变台工程项目在数据处理方面能力有限,对需要重点管控的建设成本偏差指标的识别能力较弱,导致配电变台工程中长期存在的一些偏差指标难以得到及时地管控。设计基于模糊Petri网理论配电变台工程建设成本偏差指标的诊断模型及预警机制,并通过案例分析诊断出配电变台工程建设成本中须进行重点管控的偏差指标,预警后续可能会出现偏差的建设成本指标。所提出的诊断与预警方法可以为配电变台工程成本管理提供新思路。

基于物联网的加权模糊petri网电网故障诊断研究

为了解决电力SCADA系统监测数据存在漏报误报等情况造成故障诊断结果不可靠的问题,文章提出基于物联网的加权模糊petri网电网故障诊断方法。首先,考虑保护与断路器动作的逻辑顺序,对权值进行合理的设定;其次,对电网拓扑结构进行分析,建立故障元件按方向蔓延的加权模糊petri网模型;最后,将故障诊断结果与传感器网络监测到的温度数据相结合,分析故障诊断结果可信度的可靠性。仿真结果表明,所提出的基于物联网的加权模糊petri网电网故障诊断方法在监测中心获取信息不完备的情况下,仍可以得出正确的诊断结果,具有较高的适应性和容错性。

A FUZZY REASONING PETRI NET MODEL AND ITS REASONING ALGORITHM

This paper compared the difference between the traditional Petri nets and reasoning Petri nets(RPN),and presented a fuzzy reasoning Petri net(FRPN) model to represent the fuzzy production rules of a rule based system.Based on the FRPN model,a formal reasoning algorithm using the operators in max algebra was proposed to perform fuzzy reasoning automatically.The algorithm is consistent with the matrix equation expression method in the traditional Petri net.Its legitimacy and feasibility were testified through an example.

Dynamic properties of fuzzy Petri net model and related analysis

Fuzzy Petri net(FPN) has been extensively applied in industrial fields for knowledge-based systems or systems with uncertainty.Although the applications of FPN are known to be successful,the theoretical research of FPN is still at an initial stage.To pave a way for further study,this work explores related dynamic properties of FPN including reachability,boundedness,safeness,liveness and fairness.The whole methodology is divided into two phases.In the first phase,a comparison between elementary net system(EN_system) and FPN is established to prove that the FPN is an extensive formalism of Petri nets using a backwards-compatible extension method.Next,current research results of dynamic properties are utilized to analyze FPN model.The results illustrate that FPN model is bounded,safe,weak live and fair,and can support theoretical evidences for designing related decomposition algorithm.

A STUDY OF FUZZY LOGICAL PETRI NETS AND ITS APPLICATION

In this paper, a fuzzy Petri net approach to modelling fuzzy rule-based reasoning is proposed. Logical Petri net (LPN) and fuzzy logical Petri net (FLPN) are defined. The backward reasoning algorithm based on sub-fuzzy logical Petri net is given. It is simpler than the conventional algorithm of forward reasoning from initial propositions. An application to the partial fault model of a car engine in paper Portinale's(1993) is used as an illustrative example of FLPN.

A reliable routing algorithm based on fuzzy Petri net in mobile ad hoc networks

A novel reliable routing algorithm in mobile ad hoc networks using fuzzy Petri net with its reasoning mechanism was proposed to increase the reliability during the routing selection. The algorithm allows the structured representation of network topology, which has a fuzzy reasoning mechanism for finding the routing sprouting tree from the source node to the destination node in the mobile ad boc environment. Finally, by comparing the degree of reliability in the routing sprouting tree, the most reliable route can be computed. The algorithm not only offers the local reliability between each neighboring node, but also provides global reliability for the whole selected route. The algorithm can be applied to most existing on-demand routing protocols, and the simulation results show that the routing reliability is increased by more than 80% when applying the proposed algorithm to the ad hoc on demand distance vector routing protocol.

Intuitionistic Fuzzy Petri Nets Model Based on Back Propagation Algorithm for Information Services

Intuitionistic fuzzy Petri net is an important class of Petri nets,which can be used to model the knowledge base system based on intuitionistic fuzzy production rules.In order to solve the problem of poor self-learning ability of intuitionistic fuzzy systems,a new Petri net modeling method is proposed by introducing BP(Error Back Propagation)algorithm in neural networks.By judging whether the transition is ignited by continuous function,the intuitionistic fuzziness of classical BP algorithm is extended to the parameter learning and training,which makes Petri network have stronger generalization ability and adaptive function,and the reasoning result is more accurate and credible,which is useful for information services.Finally,a typical example is given to verify the effectiveness and superiority of the parameter optimization method.

基于模糊Petri网的“网–源–储–车”动态阈值能量管理策略研究

轨道交通作为电力系统的主要用能对象之一,每年消耗大量电能用于电力机车牵引。因此,降低牵引能耗、提升供能系统的弹性与效能对促进碳达峰、碳中和具有重要的现实意义。轨道交通“网–源–储–车”协同供能系统在传统牵引供电架构的基础上引入了储能系统与新能源发电系统,然而,如何实现牵引负荷、储能系统及新能源发电系统的高效能源自洽,减少双向波动性与不确定性对能量管理系统的影响成为了新的难题。为实现以上目标,减轻牵引负荷对牵引网的功率冲击,延长储能系统的使用寿命,本文提出了一种基于模糊Petri网(fuzzy Petri nets,FPN)的“网–源–储–车”动态阈值能量管理策略。该策略在“网–源–储–车”基本功率分配框架的基础上,设定了多工况下牵引供电系统与储能系统、新能源发电系统的动态能量交互规则,可适用于不同架构的“网–源–储–车”协同供能体系;在此基础上,以电力机车功率与储能系统寿命作为模糊Petri网的输入参数,经过模糊化、Petri网推理、反模糊化等操作后实现对放电阈值的自适应动态调整。本文以某牵引变电所实测数据作为测试案例,仿真结果表明:相较于基于固定阈值的能量管理策略,基于模糊Petri网的动态阈值管理策略能够有效提升能量回馈效率与再生制动能量储存效率,同时,增加光伏发电系统的利用电度,降低电力机车经由接触网从电力系统取能的平均功率及储能系统的平均放电深度;对延长储能系统的预计寿命、提升协同供能系统的能量利用效率与运行经济性具有积极意义。

Method of Dynamic Knowledge Representation and Learning Based on Fuzzy Petri Nets

A method of knowledge representation and learning based on fuzzy Petri nets was designed. In this way the parameters of weights, threshold value and certainty factor in knowledge model can be adjusted dynamically. The advantages of knowledge representation based on production rules and neural networks were integrated into this method. Just as production knowledge representation, this method has clear structure and specific parameters meaning. In addition, it has learning and parallel reasoning ability as neural networks knowledge representation does. The result of simulation shows that the learning algorithm can converge, and the parameters of weights, threshold value and certainty factor can reach the ideal level after training.

FINE-GRAINED DISTRIBUTED MULTIMEDIA SYNCHRONIZA-TION MODEL——ENHANCED FUZZY-TIMING PETRI NET

A fine grained distributed multimedia synchronization model——Enhanced Fuzzy timing Petri Net was proposed which is good at modeling indeterminacy and fuzzy. To satisfy the need of maximum tolerable jitter, the sufficient conditions are given in intra object synchronization. Method to find a proper granularity in inter object synchronization is also given to satisfy skew. Exceptions are detected and corrected as early as possible using restricted blocking method.