Graphical-based reliability evaluation of multiple distinct production lines

This paper proposes a graphical-based methodology to evaluate the performance of a manufacturing system in terms of network model.We focus on a manufacturing system which consists of multiple distinct production lines.A transformation technique is developed to build the manufacturing system as a manufacturing network.In such a manufacturing network,the capacity of each machine is multistate due to failure,partial failure,or maintenance.Thus,this manufacturing network is also regarded as a multistate network.We evaluate the probability that the manufacturing network can meet a given demand,where the probability is referred to as the system reliability.A simple algorithm integrating decomposition technique is proposed to generate the minimal capacity vectors that machines should provide to eventually satisfy demand.The system reliability is derived in terms of such capacity vectors afterwards.A practical application in the context of IC card manufacturing system is utilized to demonstrate the performance evaluation procedure.     

离散时间修理延迟单部件可修系统的可靠性分析

针对离散时间下修理有延迟的单部件可修系统,建立了系统状态转移的数学模型。该模型假定系统有正常、维修和故障后待修三种状态,并且系统寿命、修复时间和等待修理时间均遵从一般离散分布。利用随机过程的方法,研究了该可修系统状态之间的转移关系。在该模型的基础上得到了系统可靠度、可用度、平均故障次数等常用可靠性指标。最后,通过一组算例来说明了该模型的有效性。     

H_∞-based fault detection for nonlinear networked systems with random packet dropout and probabilistic interval delay

The fault detection problem for the nonlinear networked control system(NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller(S/C) and from controller to actuator(C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example.     

基于AADL体系结构模型的构件系统可靠性评估

为了支持新一代航电系统在体系结构设计阶段进行系统可靠性分析和评估,对复杂嵌入式系统利用体系结构分析与设计语言(architecture analysis and design language, AADL)进行系统的建模。提出了一种基于AADL系统体系结构模型的可靠性建模方法,设计出一套转换规则,对AADL体系结构模型的软硬件构件进行模型转换,实现从AADL系统体系结构可靠性模型到系统体系结构广义随机Petri网(system architecture general stochastic Petri net,SAGSPN)的转换,并基于加权的SAGSPN可靠性计算模型对系统进行可靠性评估。最后通过对某飞控系统进行可靠性评估,验证了方法的有效性,证明该方法对航电系统的体系结构设计提供了支持。     

Capacitated stochastic coloured Petri net-based approach for computing two-terminal reliability of multi-state network

Classical network reliability problems assume both networks and components have only binary states,fully working or fully failed states.But many actual networks are multi-state,such as communication networks and transportation networks.The nodes and arcs in the networks may be in intermediate states which are not fully working either fully failed.A simulation approach for computing the two-terminal reliability of a multi-state network is described.Two-terminal reliability is defined as the probability that d units of demand can be supplied from the source to sink nodes under the time threshold T.The capacities of arcs may be in a stochastic state following any discrete or continuous distribution.The transmission time of each arc is also not a fixed number but stochastic according to its current capacity and demand.To solve this problem,a capacitated stochastic coloured Petri net is proposed for modelling the system behaviour.Places and transitions respectively stand for the nodes and arcs of a network.Capacitated transition and self-modified token colour with route information are defined to describe the multi-state network.By the simulation,the two-terminal reliability and node importance can be estimated and the optimal route whose reliability is highest can also be given.Finally,two examples of different kinds of multistate networks are given.     

在轨空间智能制造:分布式调度建模与优化

在轨空间制造系统是在行星大气层外的需要地面工厂、在轨空间工厂、天地运载工具协同的以进行空间设施建造为目标的一类分布式制造系统.分布式调度建模和高效优化求解技术是实现在轨空间智能制造的关键技术之一.本文针对一类具有组件地面分布式制造及运输、地空分批次运输、组件在轨装配等典型特点的在轨空间智能制造系统,将其分解为分布式同质流水线调度,考虑运输时间的同速并行机调度,考虑工件释放时间、机器可用时间、机器处理能力的单机批调度以及考虑组件释放时间、优先约束的单机调度等问题,并基于模型协调思想建立以最小化组件生产到产品装配总时长为目标的分布式多阶段调度模型.进而,将用于求解连续优化问题的易理优化算法扩展到离散调度问题,提出求解该分布式调度问题的基于易理优化的模因算法.基于中规模、大规模算例的仿真结果和算法分析比较表明:相较于粒子群算法、教学算法、水波算法等智能优化算法,所提算法是一种求解分布式多阶段调度问题的可行、有效算法.值得一提的是,这是第一篇关于在轨空间智能制造系统调度优化的研究.     

一类含有随机输入时延和故障的离散系统H∞控制

研究了一类具有控制输入时延的离散系统H_∞可靠性控制问题,提出了具有实际意义的服从某种概率分布的随机故障模型。假设输入时延符合齐次Markov分布,在控制器的设计中利用了控制器的历史信息, 把系统转换为无时延的Markov 跳变系统,根据Lyapunov稳定性理论和线性矩阵不等式(linear matrix inequality, LMI)方法,给出了故障分布依赖的H_∞均方稳定且具有H_∞范数界γ的容错控制器解的存在条件。最后, 通过算例验证了本方法的有效性。     

基于单件小批量生产企业的动态随机生产函数

本文以单件小批量订货生产类型企业为对象,通过引入某些主要的随机因素,建立了动态随机生产函数模型．与现有模型相比,能更有效地描述生产系统的实际状况．模型中考虑的随机因素有订单的内容及其到达时间的随机性、影响加工时间的随机因素以及原材料属性的随机性     

改进TOPSIS的多态融合直觉模糊威胁评估

针对防空作战中的目标威胁评估问题,提出一种新的多时刻融合直觉模糊集排序模型。首先,依据目标威胁属性的主、客观权重得到综合权重。然后,通过逼近理想解排序法来衡量直觉模糊集信息量的大小,利用直觉模糊熵来表征直觉模糊集信息的可靠性,并结合决策者的风险偏好,构建了基于信息量和不确定性的直觉模糊集排序模型,得出单时刻的目标威胁排序。最后,利用泊松分布逆形式构建了时间序列权重以融合多个时刻的决策信息,得出最终的目标威胁排序。仿真结果表明,所提算法综合了多时刻的决策信息,并可根据决策者的风险偏好进行调整,灵活性强,可靠性高。     

System reliability of assured accuracy rate for multi-state computer networks from service level agreements viewpoint

From the viewpoint of service level agreements, the transmission accuracy rate is one of critical performance indicators to assess internet quality for system managers and customers. Under the assumption that each arc＇s capacity is deterministic, the quickest path problem is to find a path sending a specific of data such that the transmission time is minimized. However, in many real-life networks such as computer networks, each arc has stochastic capacity, lead time and accuracy rate. Such a network is named a multi-state computer network. Under both assured accuracy rate and time constraints, we extend the quickest path problem to compute the probability that d units of data can be sent through multiple minimal paths simultaneously. Such a probability named system reliability is a performance indicator to provide to managers for understanding the ability of system and improvement. An efficient algorithm is proposed to evaluate the system reliability in terms of the approach of minimal paths.     

利用极小割计算随机流网络可靠度的一种算法

对随机流网络可靠度的计算问题进行了研究.提出了网络元件(边和结点)容量下确界的概念,在求基于每个极小割集的每个元件的容量向量时,对其满足的约束条件进行了改进,使其可行解集合大大减小.同时给出了两个引理,根据这两个引理,使得求基于极小割集的所有d-上界点变得非常简单,从而得到了一个计算随机流网络最大流量不少于给定需求流量d+1的可靠度的有效算法.最后,通过实例验证了该方法的有效性.     

Finite-time stability and stabilization of Markovian switching stochastic systems with impulsive effects

Many practical systems in physics,biology,engineering and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynamical processes.The problems of finite-time stability analysis are investigated for a class of Markovian switching stochastic systems,in which exist impulses at the switching instants.Multiple Lyapunov techniques are used to derive sufficient conditions for finite-time stochastic stability of the overall system.Furthermore,a state feedback controller,which stabilizes the closed loop systems in the finite-time sense,is then addressed.Moreover,the controller appears not only in the shift part but also in the diffusion part of the underlying stochastic subsystem.The results are reduced to feasibility problems involving linear matrix inequalities (LMIs).A numerical example is presented to illustrate the proposed methodology.     

基于市场的再制造P制造系统集成库存随机最优控制研究

在逆向物流中,再制造零部件的数量具有不确定性.根据这一特点,将其看成是随机参数,给出了再制造/制造系统集成库存模式.基于市场对再生品和新产品的不同需求,利用马尔科夫决策理论对具有随机再制造零部件的再制造/制造系统集成库存进行研究,考虑再制造零部件单位成本、新零部件(新购或新制造)单位成本和固定成本及有缺货赔偿的情况,给出了马尔科夫决策过程模型,得到了随机最优控制策略,并用案例进行分析验证.     

Ho∞-based fault detection for nonlinear networked systems with random packet dropout and probabilistic interval delay

The fault detection problem for the nonlinear networked control system (NCS) with packet dropout and delay is investigated.A nonlinear stochastic system model is proposed to account for the NCS with random packet dropout and networkinduced non-uniformly distributed time-varying delay in both from sensor to controller (S/C) and from controller to actuator (C/A).Based on the obtained NCS model,employing an observer-based fault detection filter as the residual generator,the addressed fault detection problem is converted into an auxiliary nonlinear H∞ control problem.Then,with the help of Lyapunov functional approach,a sufficient condition for the desired fault detection filter is constructed in terms of certain linear matrix inequalities,which depend on not only the delay interval but also the delay interval occurrence rate and successful packet communication rate.Especially,a trade-off phenomenon between the maximum allowable delay bound and successful data packet transmission rate is found,which is typically resulted from the limited bandwidth of communication networks.The effectiveness of the proposed method is demonstrated by a simulation example.     

COORDINATING PRODUCTION AND RECYCLING DECISIONS WITH STOCHASTIC DEMAND AND RETUR

In this paper, the joint production and recycling problem is investigated for a hybrid manufacturing and remanufacturing system where brand-new products are produced in the manufacturing plant and recycled products are remanufactured into as-new products in the remanufacturing facility. Both the brand-new products and remanufactured products are used to satisfy customer demands. Returns of used products that are recycled from customers are assumed to be stochastic and nonlinearly price-dependent. A mathematical model is proposed to maximize the overall profit of the system through simultaneously optimizing the production and recycling decisions, subject to two capacity constraints ? the manufacturing capacity and the remanufacturing capacity. Based on Lagrangian relaxation method, subgradient algorithm and heuristic algorithm, a solution approach is developed to solve the problem. A representative example is presented to illustrate the system, and managerial analysis indicates that the uncertainties in demand and return have much influence on the production and recycling policy. In addition, twenty randomly produced examples are solved, and computational results show that the solution approach can obtain very good solutions for all examples in reasonable time.     

Coordinating production and recycling decisions with stochastic demand and return

In this paper, the joint production and recycling problem is investigated for a hybrid manufacturing and remanufacturing system where brand-new products are produced in the manufacturing plant and recycled products are remanufactured into as-new products in the remanufacturing facility. Both the brand-new products and remanufactured products are used to satisfy customer demands. Returns of used products that are recycled from customers are assumed to be stochastic and nonlinearly price-dependent. A mathematical model is proposed to maximize the overall profit of the system through simultaneously optimizing the production and recycling decisions, subject to two capacity constraints — the manufacturing capacity and the remanufacturing capacity. Based on Lagrangian relaxation method, subgradient algorithm and heuristic algorithm, a solution approach is developed to solve the problem. A representative example is presented to illustrate the system, and managerial analysis indicates that the uncertainties in demand and return have much influence on the production and recycling policy. In addition, twenty randomly produced examples are solved, and computational results show that the solution approach can obtain very good solutions for all examples in reasonable time.     

基于变迁可靠性的随机Petri网最优路径序列寻找

为了解决随机Petri网的路径寻优问题,在变迁中引进了可靠性的特性,并假设变迁的寿命服从威布尔分布模型,然后根据蚁群算法和时间Petri网的特点提出了一种网络元素可以记录少量信息的带可靠性的记忆时间随机Petri网。在网络运行时,大量托肯在网络中行走并且在行走过程中留下信息素,以此来调整托肯的路径选择。在满足一定可靠性的前提下,在延迟越短的路径上蚂蚁将留下越多的信息素,最终在延迟最短的路径上形成清晰的蚁路。因为变迁的可靠性随时间的增加而不断减小,当一段时间过后路径的可靠性不能满足要求时,需要重新选择一条满足可靠性要求且相对延迟最短的新路径。仿真结果表明,托肯可以有效地在最优路径上形成清晰的蚁路,并且能随着可靠性的不断变化寻找新的最优路径。     

基于响应面和NSGA-II的AGV系统多目标优化配置

AGV（automated guided vehicle）系统对于制造系统的生产柔性和生产效率具有重要作用,由于AGV系统具有许多的变量且有动态性、随机性特点,其优化配置比较复杂。提出了一种将系统仿真、数学解析和多目标优化相结合的方法,对AGV系统进行了优化配置;运用离散事件仿真模拟AGV系统运行,利用敏感性分析分离设计变量,采用析因试验和响应面方法拟合多目标优化数学模型,基于非支配解排序多目标遗传算法求解多目标优化解。通过AGV系统实例,证明了该方法的有效性,可为制造系统和物流仓储领域中AGV系统的优化配置提供一种有效的系统性分析方法。     

考虑多参考点的基于前景随机占优准则的随机多属性决策

针对随机多属性决策问题,考虑决策者心理行为,提出一种基于多参考点的前景随机占优多属性决策方法.首先,以决策者属性期望作为参考点,根据累积前景理论将决策矩阵转化为损益矩阵.其次,依据前景随机占优准则构建前景随机占优关系矩阵,进而得到前景随机占优度矩阵.进一步,考虑属性相关关系,运用模糊测度得到方案综合占优度矩阵,并运用PROMETHEE Ⅱ方法对方案进行排序.最后,案例分析验证了该方法的可行性和有效性.     

冷贮备离散时间状态聚合可修系统的可靠性

对一个离散时间可修系统的可靠性进行了研究,系统由两个部件和一个修理工组成,一个部件在线工作,另一个冷贮备,修理工具有多重休假策略,故障部件修复如新;假设部件正常工作时间、修理时间、修理工的休假时间服从不同参数的离散位相型分布。通过运用kronecker算子和聚合随机过程理论,分别推导出系统在瞬态和稳态情况下的一些可靠性指标:可用度、故障的条件概率以及可靠度。所得结果表明离散时间情形并不是连续时间情形的一个特殊情况。最后用一个数值算例对所得结论进行了验证。