动态环境下工作分析定性模拟方法研究

传统工作分析方法的工作环境静态假设与企业实际面临的动态环境现实相违背,使得其工作分析结果缺乏动态适应性,可以采用定性模拟的方法对原有的分析结果进行修正.首先设计了工作分析的定性因果关系模型、变量知识的定性表述方法、状态变量转换规则及模拟步骤;为防止模拟组合爆炸,设计了基于管理常识的过滤器;最后给出了企业管理岗位职能变化过程的模拟应用实例,模拟结果符合企业管理相关理论.     

基于BP神经网络的D-S证据理论及其应用

命题基本概率分配（BPA）的确定是D-S证据理论得以广泛应用的关键之一。目前，大部分确定方法受专家知识偏好影响较大，难以反映客观情况。将BP网络运用到基本概率分配的确定过程中，使得BP网络和D-S证据理论两者有机地联合应用，这样既可利用D-S证据理论来表达和处理不确定信息，又可以充分发挥BP网络的自学习、自适应和容错能力。文中建立了基于BP网络的D-S证据理论的故障诊断模型，并给出了证据的融合算法。仿真实验表明，该模型可行。     

基于知识工程复杂产品开发过程的模型研究

 为了提高复杂产品开发的效率,驾驭复杂产品开发过程各个环节相互关联的复杂性,提出一种基于知识工程的复杂产品开发过程新模型.该模型把知识工程理论融入复杂产品开发全生命周期过程中,通过知识推理技术从数据库和知识库中获取相应开发阶段的知识和数据来驱动和指导整个复杂产品开发过程,以更好地重用设计知识.研究了该模型的关键技术,包括复杂产品开发知识处理技术和基于知识的CAD/CAM/CAE/CAPP集成技术,提出了两种知识处理方法,即基于规则-对象-框架的知识处理方法和基于规则-实例的知识处理方法,并研究了相应的推理算法;以知识库、数据库、规则库和实例库为基础,通过PDM,STEP中型文件、规则、实例和知识等,实现CAD/CAM/CAE/CAPP集成.最后,通过数据库技术、编程语言VC# . NET和CATIA软件实现了隧道掘进机（TBM）主机的快速设计系统,有效地减少了隧道掘进机主机开发的复杂性和缩短开发周期,以TBM主机为应用实例进一步介绍该模型的合理性和有效性.     

随机网络瓶颈容量扩张的期望值模型

在不确定的环境下,怎样去增加一组边的容量到一个指定的瓶颈容量,以至于网络瓶颈扩张的费用最小。假定每一条边的单位扩张费用形是一个随机的变量,它服从正态分布。带有随机单位扩张费用W的网络瓶颈客量扩张问题可以根据一些概率统计规则,列出它的期望值模型的通用表达式。随后,网络瓶颈容量算法、随机模拟方法和遗传算法将合成在一起,设计出该问题的混合智能算法。最后。给出数值案例。     

基于全生命周期的机床产品协同设计知识专家系统

在面向机床产品协同设计过程中,多领域专家常常会遇到许多涉及产品全生命周期中精确或模糊的知识,如何正确地应用这些知识是机床产品协同设计中必须解决的首要问题.本文采用协同设计知识专家系统将基于知识的规则库和CBR方法有机地结合在一起,可以较好地获取与处理机床产品协同设计过程中的相关知识.     

人力资源管理系统定性模拟方法研究

构建了适用于人力资源管理的基于过程知识库的定性模拟方法,提出了相应的定性知识描述方法,设计了定性过程知识库、定性运算与定性约束和定性模拟步骤。在应用基于过程知识库的定性模拟方法对研发团队行为系统的研究中,发现系统从中性状态出发,在环境因素波动过程中,在成本一定的条件下,要获得较高的收益,管理者就应该在第一阶段环境因素有利时,采取措施加强目标引导,防止在环境因素恶化阶段系统陷入恶性循环。     

集成因果推理和QSIM的人群行为定性模拟

集成了定性因果推理法和QSIM(Qualitative Simulation)算法，并根据组织行为学相关理论，提出并设计了用于定性模拟的人群行为及其影响因素的描述方法，包括：外部环境描述、管理措施描述、人群内各要素状态的描述、各要素相互关系的描述、各要素变化过程的描述、人群所处文化环境的描述。在此基础上，根据组织行为学常识，设计了人群行为变化过程的定性模拟方法，包括规则和算法步骤。从一个实例可知，本文所提出的方法易于理解和操作，能用于描述、预测人群行为变化过程。     

多失效模式典型结构系统可靠性稳健设计方法研究

应用随机摄动技术与二阶矩方法,结合概率网络估算法（Probability Network Evaluation Technique）,讨论了多失效模式下结构系统的可靠性和可靠性灵敏度问题,并进一步对结构系统的可靠性稳健设计进行了分析。获得了不同失效模式间的相关统计特性,应用概率网络估算法确定了系统的代表失效模式,得出了...     

任务型群体工作行为的定性模拟研究

综合企业管理、心理学、群体动力学中关于群体的研究,构建了一个任务型群体工作过程模型,描述了影响群体工作状态的主要因素及相互作用关系.而后按照QSIM算法思路,结合有关群体工作行为的常识和专家知识,设计了变量间的作用规则.对变量状态变化的多个可能分支,以约定的概率分布进行选择,以此避免模拟结果的组合爆炸.根据规则设计了模拟算法,并用VB编程进行了模拟.多次模拟结果的统计分析与实际情况基本符合,表明这一方法可以用于群体工作行为的虚拟实验研究.     

建筑结构相关荷载组合的平稳二项随机过程方法

目前建筑结构设计和分析的荷载组合采用的是经验性的荷载组合规则,荷载组合结果具有较大的随意性,不能计算荷载组合值的保证率。在将随时间变化的荷载随机过程假定为平稳二项随机过程的基础上,研究多个相关或不相关荷载(或荷载效应)组合问题。考虑参与组合的荷载随机变量间的相关性,确定了组合荷载随机过程的参数;根据最大熵原理确定了荷载组合随机过程的任意时段幅值随机变量的概率分布,从而建立了相关随机荷载的组合方法;结合现行规范设计方法,进一步讨论了荷载组合系数的确定;最后采用MonteCarlo试验验证了本文的荷载组合方法,并对常见的几种经验荷载组合规则进行了概率校核。     

System Failure Analysis Through Counters of Petri Net Models

Petri nets are a powerful technique widely used in the modeling and analysis of complex manufacturing systems and processes. Due to their capability in modeling the dynamics of the systems, Petri nets have been combined with fault tree analysis techniques to determine the average rate of occurrence of system failures. Current methods in combining Petri nets with fault trees for system failure analysis compute the average rate of occurrence of system failures by tracking the markings of the Petri net models. The limitations of these methods are that tracking the markings of a Petri net represented by a reachability tree can be very complicated as the size of the system grows. Therefore, these methods offer less flexibility in analyzing sequential failures in the system. To overcome the limitations of the current methods in applying Petri nets for system failure assessment, this paper expands and extends the concept of counters used in Petri net simulation to perform the failure and reliability analysis of complex systems. The presented method allows the system failures to be modeled using general Petri nets with inhibitor arcs and loops, which employs fewer variables than existing marking‐based methods and substantially accelerates the computations. It can be applied to real system failure analysis where basic events can have different failure rates. Copyright © 2003 John Wiley & Sons, Ltd.     

基于受控混杂Petri网(CHPN)的分层优化模型及其在炼油厂氢气管理中的应用

提出了一种基于受控混杂Petri网(CHPN)的分层优化建模结构,并将其应用于炼油厂的氢气网络优化管理中.这种分层优化结构将CHPN建立的过程仿真模型同传统的数学优化方法紧密结合在一起,上层的数学优化模型根据经济指标寻求最优解,下层CHPN在上层最优解的控制下运行,可以根据工厂的实际生产条件的改变在计划期内及时调整调度安排,并保证经济指标的最优性.炼油厂氢气平衡管理建模实例显示,通过该方法获得的炼油厂氢气平衡调度方案减少了炼油厂生产过程中氢气资源的浪费现象,提高了企业的经济效益.     

A Petri net based design engine for manufacturing systems

Support for the efficient design and operation of complex manufacturing systems requires an integrated modelling, analysis, and control methodology as well as its implementation in a software tool. In this paper the Petri net based design engine TimeNET is presented for this task. Petri nets are able to capture the characteristic features of manufacturing systems in a concise form. A subclass of coloured Petri nets is used, which has been developed especially for the application area of manufacturing. Structure and work plans are modelled separately. Stochastic as well as deterministic and more general distributions are adopted for the firing times of transitions. Fundamental questions about system properties can be answered using qualitative analysis. For an efficient performance and dependability prediction, different evaluation techniques are proposed: direct numerical analysis, approximate analysis, and simulation. Finally, the model can be used to evaluate different control strategies and to control the manufacturing system directly. There is no need to change the modelling methodology, thus avoiding additional effort, for example for model conversion. In the paper this necessary steps are described using an application example.     

Modular Petri nets for simulation of flexible production systems

The use of Petri nets for modelling, analysing and simulating complex distributed production systems meets serious problems when the size of the model grows. Therefore, it would be very useful to decompose a Petri net based model into smaller models linked with one another. The aim of this paper is to suggest and discuss some possible definitions of Modular Petri nets. This is accomplished by introducing the concept of Petri subnet. Two possible definitions are proposed and the meaning and the usefulness with respect to both model definition and model executability for simulation are pointed out. All definitions are given for the basic model of Petri nets. The extension of modularity concepts to high level Petri nets is shown to be possible in the second part of the paper, where an application is illustrated. In particular an algorithm is given which allows automatic composition of subnets into a larger model     

过程激励的定性模拟方法及原型系统

为了给企业选择激励措施时提供一种虚拟实验工具,基于物理系统定性模拟及其它多种思想,设计了过程激励的定性模拟方法,开发了原型系统.其中,借鉴模糊数学和QSIM（Qualitative Simulation）算法的思路表述定性状态变量;利用改进的因果关系图表述激励措施与人群激励效果之间、以及与激励成本之间的定性关系;采用IF-THEN方式设计了状态变量的转换规则;借鉴纳什均衡的思想,提出激励-满意均衡概念,用于过滤各模拟阶段的不合理的转换;链接前述各方法,设计了模拟步骤;为实现上述方法,用VB 6.0和Matlab 6.10开发了原型系统.实验表明,通过本文的方法,系统所得的结果是符合常理的.     

基于赋时Petri网的成组生产单元缓冲区建模

以CD造船厂的某成组生产单元为研究对象,在对不同功能和结构的在制品缓冲区进行分类的基础上,建立了该生产单元的扩展赋时库所Petri网模型;将此Petri网映射为eM-Plant软件中的仿真模型,通过对在制品缓冲区库存量仿真数据的监控和分析,讨论了该成组生产单元的瓶颈环节、设备的负荷状况、零件排序调度的优化与否以及生产的连续性和稳定性.     

Use of Petri Nets to Model the Maintenance of Wind Turbines

With large expansion plans for the offshore wind turbine industry, there has never been a greater need for effective operations and maintenance. The two main problems with the current operations and maintenance of an offshore wind turbine are the cost and availability. In this work, a simulation model has been produced of the maintenance process for a wind turbine with the aim of developing a procedure that can be used to optimise the process. This initial model considers three types of maintenance—periodic, conditional and corrective—and also considers the weather in order to determine the accessibility of the turbine. Petri nets have been designed to simulate each type of maintenance and weather conditions. It has been found that Petri nets are a very good method to model the maintenance process because of their dynamic modelling and adaptability and their ability to test optimisation techniques. Because of their versatility, Petri net models are developed for both system hardware and the maintenance processes, and these are combined in an efficient and concise manner. Copyright © 2014 John Wiley & Sons, Ltd.     

基于随机Petri网的铜带拉弯矫直机可用度分析

为了合理确定铜带拉弯矫直机的校验周期,提高其生产效率,确保其矫直精度,根据某铜板带公司拉弯矫直机9个月的维修数据,对拉弯矫直机的失效模式进行随机Petri网建模,将系统失效模式转换成相应的随机Petri网;基于马尔科夫过程对随机Petri网进行瞬态概率求解,并得到该拉弯矫直机失效模式的稳态概率;利用或门对应的随机Petri网模型分析,计算不同校验周期下拉弯矫直机的可用度.综合考虑设备可用度和经济效益,确定了合理的校验周期,为拉弯矫直机的长周期运行提供了依据.