半导体生产线自适应派工规则

高度不确定的半导体制造环境迫切需要能够快速响应生产线实际状态的调度方法,为此,在充分考虑半导体生产线特点的基础上,给出了同时考虑混合加工方式、上下游负载均衡与工件准时交货需求的自适应派工算法(Self-Adaptive Dispatching Rule,SADR).首先,介绍了SADR的算法流程;其次,将历史调度方案或仿真调度方案作为学习样本,基于免疫克隆选择算法挖掘SADR参数与实际生产状态参数及期望运作性能之间的关系模型,实现SADR参数跟随生产线运作状态的实时动态调整;最后,基于实际半导体生产线模型进行仿真验证.仿真结果表明,SADR能有效提高半导体生产线的运作性能,生产线上的总工件移动步数平均提高2％,并且在超载环境下能够获得更好的效果.     

网格技术在半导体生产调度中的应用研究

网格技术是一种新型的分布计算技术,致力于解决复杂度很高的新应用问题.随着全球半导体生产规模的日益扩大,半导体生产线的优化调度问题成为学术界及工程界研究的热点.半导体生产线具有许多特殊的特点,诸如生产规模大、工件数量多、随机性大、加工成本高、高度的可重入性等,这些特点决定了原有的调度策略已不能满足半导体生产线的要求.鉴于网格技术在处理设备可扩展性和资源平衡性上的优势,主要研究将网格技术的思想用于半导体生产线的调度中.利用网格计算中的负载向量和失衡因子的概念,来控制半导体生产线上各加工机器处工件块的规模以及投料规模.通过优化算法的调度,使得半导体生产线的各加工设备负载得到平衡,设备的生产效率提高,缩短加工周期,从而达到优化生产线的目的.     

多智能体协作方法及其应用研究

将复杂系统分解成由多个智能体构成的合作多智能体系统，建立了多智能体系统的决策模型，能动态实时地计算每一时刻智能体的决策局势，适应环境的动态变化．采用多智能体方法对半导体生产进行调度，提高了半导体生产线设备的利用率，缩短了单位工件的加工时间．     

基于多Agent技术的半导体生产线动态调度研究

以提高芯片生产厂家的市场竞争力、芯片合格率和按期交货率为主要调度目标,该文提出了基于多agent技术的半导体生产线动态调度算法,各加工中心agent相互合作,调度时协同考虑上下游加工中心的信息,共同满足优化调度的目的,仿真实验证明了算法的有效性。     

一种基于负载均衡异构分布式系统的改进容错调度算法*

基于基/副版本技术提出了一种具有容错功能的静态进程调度算法。给出了一个新的设计模型,并在该模型上提出HDAL算法。此前类似负载均衡容错调度算法都是通过排序来解决故障发生前后的负载均衡调度问题。该算法与以往算法不同之处就是在不依赖排序情况下,通过引进控制进程来解决负载均衡调度问题,并且该算法的负载均衡性在一定程度上具有了可控性。最后通过模拟实验得到以下有意义的结论：在业务繁忙的异构系统中,HDAL算法比以往算法资源利用率高,负载均衡性更好,并且在调度速度上优势明显。     

视频监控系统中的VOD负载均衡改进算法

在传统轻负载优先调度负载均衡算法中,存在用户点播响应时延长且负载均衡度不高的问题。为解决上速问题,提出一种静态负载调度和动态负载迁移相结合的负载均衡算法。静态调度算法采用基于视频点播(VOD)相似度的轻负载优先算法,将相似的点播请求调度至相同的视频点播上,提高VOD的缓存命中率,以缩短点播响应时延。动态负载迁移算法采用基于缓存考虑的REM负载迁移算法,将负载由高载VOD迁移到低载VOD上,以提高负载均衡程度。实验结果表明,在典型城域视频监控系统500路点播规模下,提出的负载均衡算法与传统轻负载优先算法相比,能够缩短17.5%的点播延迟时间,降低53.4%的集群负载方差,提高了系统的负载均衡度。     

基于剩余能量的可分负载WSN能耗均衡研究

无线传感器网络( WSN)节点由于自身体积及监测环境等因素的影响,其可携带的能量有限。因此,延长网络的生存周期、均衡WSN各节点的剩余能量即成为该领域的研究热点。针对星型可分负载WSN的剩余能量模型进行优化,以经典最短时间可分负载调度为基础,提出2种优化调度算法：剩余能量排序负载调度算法( RESS )和虚拟能力排序负载调度算法( VASS)。仿真实验结果验证了RESS算法与VASS算法在延长网络生存周期方面的有效性,并表明VASS算法比RESS算法更稳定。     

基于轮转周期的动态反馈负载均衡算法

网络管理系统中管理端逐步采用分布式集群构架,通过负载均衡算法调度客户端请求,并将客户端请求分配给多个事务节点进行并行处理。为进一步提高集群系统服务的性能,文中在研究以往负载均衡算法的基础上,提出了一种基于轮转周期的动态反馈负载均衡算法。该算法设计了一种基于剩余资源动态权值的节点剩余负载能力计算方法的动态反馈机制;并在动态反馈负载均衡算法的一个采样周期内引入轮转周期对客户端请求均衡分配。通过实验比较分析,该算法能获得更好的负载均衡效果。     

基于流调度选择的DCN动态负载均衡算法

针对数据中心网络(data center network,DCN)动态调度导致的负载不均衡问题,提出了基于流调度选择的动态负载均衡(dynamic load balancing based on flow scheduling selection,DLBFSS)算法。该算法首先计算拥塞链路上各条大流的等价最短路径,并删除不满足流带宽需求的路径;然后计算剩余路径的可用吞吐量,选择可用吞吐量最大的路径作为最优调度路径;最后根据大流的带宽和最优路径的负载定义调度的拥塞概率,将拥塞概率作为大流调度选择的依据。实验结果表明,与传统ECMP（equal-cost multi-path）路由和现有大流调度算法相比,DLBFSS能够减小网络时延,提高流的带宽利用率,保证了更好的负载均衡。     

云计算和多维QoS环境中基于蚁群优化算法在虚拟机资源负载均衡问题中的研究

针对云计算环境中虚拟机资源负载均衡问题,并为实现云计算下虚拟机资源负载均衡高效调度以满足用户的QoS需求,提出了一种基于多维QoS实现负载均衡的虚拟机资源调度方法。首先,在云计算环境下建立多维QoS网络环境的数学模型;然后,提出一种基于蚁群算法的优化算法,用于实现云计算环境中虚拟机资源高效调度;最后,在云仿真平台CloudSim上进行仿真实验。实验结果表明,相对于其他资源调度算法,所提算法能高效解决云计算下虚拟机资源调度问题,减少虚拟机资源负载均衡离差,具有更好的性能,能完全满足云计算下和多维QoS环境下虚拟机资源负载均衡的需求。     

基于反馈平衡的多生产线调度算法与仿真

研究生产线平衡调度优化问题。传统的生产线产品调度中,由于生产线上的产品数量不定,造成生产线的负荷不平衡,容易造成生产线工序上产品堆积,导致生产线平衡能力下降,流水线发生阻塞。为了解决上述6问题,提出了一种反馈信息平衡的生产线产品调度算法。将产品在生产线上流动的顺畅情况,作为反馈信息传递给生产调度端。调度算法把各种信息作为指导后续生产线产品选择工序先后次序的依据,使得在生产线上负荷大幅增加的情况下,通过反馈信息改变产品调度顺序,使得生产线负荷达到平衡。实验结果表明,反馈信息平衡算法在产品负荷较大的情况下,有效地提高生产线的平滑指数,提高了生产线的效率。     

装配线生产节拍优化系统的研究与开发

为了探讨装配线生产节拍的调整与工作站分配的关系,寻求最优生产节拍,使装配线达到最大的平衡率,以韩格逊-伯尼法、最大设定准则法、优先分配后续作业最多作业法和优先分配操作时间最长作业法为依据,运用PHP开发语言,开发了装配线平衡计算机辅助系统。该系统可遍历某一范围的生产节拍,得出平衡率最高的工作站分配方案。通过对某电冰箱厂装配线的优化分析,使其平衡率提高了10%以上,验证了该系统的可行性。该装配线平衡计算机辅助系统是有效的,可为教学和工厂装配线优化提供指导。     

A recursive operator allocation approach for assembly line-balancing optimization problem with the consideration of operator efficiency

This paper addresses an optimization model for assembly line-balancing problem in order to improve the line balance of a production line under a human-centric and dynamic apparel assembly process. As the variance of operator efficiency is vital to line imbalance in labor intensive industry, an approach is proposed to balance production line through optimal operator allocation with the consideration of operator efficiency. Two recursive algorithms are developed to generate all feasible solutions for operator allocation. Three objectives, namely, the lowest standard deviation of operation efficiency, the highest production line efficiency and the least total operation efficiency waste, are devised to find out the optimal solution of operator allocation. The method in this paper improves the flexibility of the operator allocation on different sizes of data set of operations and operators, and enhances the efficiency of searching for the optimal solution of big size data set. The results of experiments are reported. The performance comparison demonstrates that the proposed optimization method outperforms the industry practice.     

A recursive operator allocation approach for assembly line-balancing optimization problem with the consideration of operator efficiency

This paper addresses an optimization model for assembly line-balancing problem in order to improve the line balance of a production line under a human-centric and dynamic apparel assembly process. As the variance of operator efficiency is vital to line imbalance in labor intensive industry, an approach is proposed to balance production line through optimal operator allocation with the consideration of operator efficiency. Two recursive algorithms are developed to generate all feasible solutions for operator allocation. Three objectives, namely, the lowest standard deviation of operation efficiency, the highest production line efficiency and the least total operation efficiency waste, are devised to find out the optimal solution of operator allocation. The method in this paper improves the flexibility of the operator allocation on different sizes of data set of operations and operators, and enhances the efficiency of searching for the optimal solution of big size data set. The results of experiments are reported. The performance comparison demonstrates that the proposed optimization method outperforms the industry practice.     

设计的作用——时代支点上的平衡砝码

设计,就像一根无形的线,牵引着两个密切相关的对象——设计提供者和设计感受者,这两者之间存在这一种平衡。在不同的社会历史背景下,平衡的成立条件也有所不同。设计,站在时代的支点上,不断保持这天平的平衡。在历史地长河中,设计有着这样的一项作用,那就是:在时代的支点上,不断平衡着设计提供者和设计感受者,起着平衡砝码的作用。     

基于动态检测技术的配电网输电线网损评估

通过直接估计输电线路电阻实现配电网电线网损评估功能,存在难以精准把握的问题,因而提出了将配电网输电线最高允许温度转化为有功功率损耗的限制,从而确立输电线短期热定值的方法。以输电线路热平衡方程中环境参量作为状态变量,根据输电线有功功率损耗与电阻、温度的的耦合关系,推导出输电线有功功率损耗变化的微分方程,以此建立系统的量测方程;同时,考虑热平衡方程式参数变化的迟缓性,建立状态变量空间表达式;继而,依据输电线有功功率损耗变化率,采用卡尔曼滤波的方法,实现对状态变量的估计。由此,完成了配电网电线网损评估的功能,为配电网输电线短期最大电流运行方式是否可行提供了解决依据。以贵州省凯里某地区220kv配电网输电线的实测数据为例,验证了本文方法的可行性与有效性。     

Intelligent workload balance control of the assembly process considering condition-based maintenance

Balancing the workloads of workstations is key to the efficiency of an assembly line. However, the initial balance can be broken by the changing processing abilities of machines because of machine degradation, and at some point, re-balancing of the line is inevitable. Nevertheless, the impacts of unexpected events on assembly line re-balancing are always ignored. With the advanced sensor technologies and Internet of Things, the machine degradation process can be monitored continuously, and condition-based maintenance can be implemented to improve the health state of each machine. With the technology of robotic process automation, workflows of the assembly process can be smoothed and workstations can work autonomously together. A higher level of process automation can be achieved. Real-time information of the processing abilities of machines will bring new opportunities for automated workload balance via adaptive decision-making. In this study, a fuzzy control system is developed to make real-time decisions to balance the workloads based on the processing abilities of workstations, given the policy of condition-based maintenance. Fuzzy controllers are used to decide whether to re-balance the assembly line and how to adjust the production rate of each workstation. The numerical experiments show that the buffer level of the assembly line with the proposed fuzzy control system is lower than that of the assembly line without any control system and the buffer level of the assembly line with another control system is the lowest. The demand can always be satisfied by assembly lines except the one with another control system since there is too much production loss sacrificed for the low buffer level. The sensitivity analysis of the control performance to the parameter settings is also conducted. Thus, the effectiveness of the proposed fuzzy control system is demonstrated, and intelligent automation can improve the performance of the assembly process by the fuzzy control system since real-time information of the assembly line can be used for adaptive decision-making.     

Development, operation, and testing of a heuristic line balancing program for a microcomputer

This paper discusses the development, operation, and testing of a heuristic line balancing program that solves the Type I Line Balance problem using a microcomputer.

The line balancing method selected was based on previous studies that compared different line balancing techniques. The model is built primarily using the Hoffman (1963) procedure with modifications described by Gehrlein and Patterson (1975). For purposes of comparison the Rank Positional Weight technique (Helgeson and Birnie, 1961) is also included in the model.

Testing included thirty-seven different balances using problems from the literature. For each balance both Rank Positional Weight and Hoffmann solutions were obtained in the forward and reverse directions. Delay factors used for the Hoffmann balances were 0.0, 0.5, 1.0, 1.25, 1.5, and 2.0. Thus for each balance problem a total of fourteen tests were conducted. The total number of tests was 518.

Four measures of performance were considered in this study. These measures of performance were: (1) the average percent a balance is above the optimum solution, in terms of number of stations; (2) time to obtain a balance; (3) the best solution in terms of the lowest number of stations and lowest standard deviation of the slack times, and (4) the largest value of minimum station slack time. Overall it was found that the Modified Hoffmann procedure with a delay factor of 1.5 performed best. The time to obtain a balance using the Modified Hoffmann procedure is significantly less than the time for a solution without the modifications.     

多目标粒子群算法在混装线再平衡中的应用

企业对产品进行创新改进,带来装配线上装配任务的变化,从而造成已平衡装配线的失衡。针对上述变化给企业混流装配线带来的影响进行了研究,以最小化生产节拍,工作站间的负荷,和工人完成新装配任务的调整成本为优化目标去建立混装线再平衡的数学模型。并设计了一种新的多目标粒子群算法求解模型,算法中引入各粒子动态密集距离去筛选外部文档的非劣解和指导全局最优值的更新,在控制解的容量同时保持Pareto解集分布均匀。此外,引入变异机制,提高了种群的全局搜索能力。最后,结合具体实例的验证表明,该改进多目标粒子群算法能有效地解决混装线再平衡问题。