失效恢复机制下的网格任务冗余调度优化

网格技术是目前学术界和工业界解决计算密集型问题的一种重要工具.由于网格系统的复杂性,网格在可靠性方面仍面临着诸多问题.针对目前网格服务可靠性低的问题,引入本地失效恢复机制,并允许资源自行调节网格任务生存时间以及失效恢复次数,从而建立更加符合实际的网格服务可靠性模型.在建模中,采取网格任务冗余调度方式,以进一步提高网格服务可靠性.基于建立的考虑失效恢复机制的网格服务可靠性模型,建立费用约束下的资源冗余调度优化模型,以获得网格服务可靠性最大的任务调度策略.针对该NP问题,采用遗传算法对该优化问题进行求解,并在求解过程中设计专门的修正算子校正不可行个体,以保障算法的正常运行.算例分析验证了算法的有效性.     

安全和容错的网格任务调度

为解决跨自治域的网络任务调度中的安全性和容错问题,提出了基于网格安全和容错的网格任务调度算法,并对用户任务的安全需求和资源的信任等级进行匹配,在系统安全等级较低且网络和主机可能失效的网格环境中进行容错任务调度。该算法根据网格系统的安全等级,自适应调整任务备份数,并对失败的任务重新调度。仿真结果表明,该算法可以有效提高不安全网格环境下的任务调度成功率,具有很好的容错性和可扩展性。     

基于实体变形的六面体网格生成方法研究

对于结构复杂的实体模型,现有的六面体网格自动生成算法无法快速生成质量较高的六面体网格。在实体变形技术的基础之上,提出一种利用顶点信息直接在原始模型中经过节点填充生成结构化六面体网格的方法。首先设计了网格节点的数据结构;其次介绍了求解填充节点所用的线性方程组的构建方法;最后,利用该方法开发了网格自动剖分程序,对复杂结构进行了网格自动剖分。     

保特征的三角网格均匀化光顺算法

为了使网格光顺算法在消除噪声的同时,保持模型特征并优化网格,提出一种保特征的网格均匀化光顺算法.首先获取二阶邻域三角面片的信息,使用改进的双边滤波器和准拉普拉斯算子预测顶点位置,然后综合拉普拉斯光顺法与平均曲率法的优点,沿顶点切平面和法矢量方向同时对网格顶点进行调整.实验结果表明,与现有方法相比,该方法可以有效去除噪声,保持三维表面模型的特征并使网格得到优化.     

一种基于混沌优化算法的PCB板元件检测方法

先进电子制造生产中经常要对PCB板元件进行检测与识别,介绍了一种基于图像模板匹配算法的PCB板元件自动快速检测方法.从检测速度和准确度出发,首先提出了一种图像相似性度量参数指标,并提出一种利用并行混沌算法融合单纯形的算法,来优化搜索图像相似性,给出了算法实现的全过程.用实际拍摄的PCB板元件进行性能测试,验证了该优化算法能提高检测速度.     

基于反馈式人工神经网络的优化算法及其应用研究

将人工神经网络理论和思想应用于优化设计算法的研究，建立了人工神经网络动力学系统与优化问题求解之间的对应关系，建立了人工神经网络系统能量函数与优化问题目标函数、人工神经网络系统演化过程与优化问题寻优过程、人工神经网络系统平衡点和优化问题最优解，以及人工神经网络系统达到平衡点时的系统状态与优化问题最优点之间的对应关系，提出了基于反馈式人工神经网络的并行优化算法并分析了这种算法的特点和应用背景。应用该算法对压铸机动模板进行了优化设计，设计结果表明了这种算法的有效性。     

网格任务调度算法的研究

提出了一种基于遗传算法和Min-Min的网格调度算法,该算法主要分为资源搜索和任务分配两部分。首先,利用遗传算法从网格的可用资源中快速地搜索出最优的或是近最优的资源;然后从任务队列中取一组任务,利用Min-Min算法把任务分配给已搜索到的资源上去执行。仿真实验结果证明:对于大规模资源的调度该算法是有效的,能够减少了任务执行时间,改善网格任务调度的效率。     

基于特征修复的网格模型光顺算法研究

将Perona Malik的灰度图非线形调整方法应用到三维网格模型 ,提出了一种任意网格模型光顺和特征修复算法。该算法通过重复对模型中三角片法矢和网格顶点进行调整 ,不仅保证了调整后网格有效去除噪声 ,还可以在充分保留原始特征的基础上 ,自动对特征进行修复。调整后模型外形光顺 ,特征线清晰突出。文中应用实例表明该算法可以在保证修复特征的前提下 ,得到更合理的三角网格模型。     

改进粒子群算法在网格资源分配中的优化

针对并行网格任务的资源分配问题,提出了一种基于并行粒子子群优化的分配算法.该算法引入效用函数,反映网格任务的偏好和目标,利用乘子法转化约束条件,导出适应度函数.最后通过粒子子群的并行寻优过程,得到资源分配的最优解.仿真实验表明了该算法的有效性,且在任务较多的情况下,优化结果好于传统粒子群算法.     

二维TiO_2纳米网格对CdTe量子点的吸附性能

通过真空蒸镀和高温煅烧方法,从蝴蝶翅膀鳞片生物模板上复制二维TiO2纳米网格,采用SEM、EDS、TEM等对其进行了表征,分析了其对CdTe量子点的吸附性能。结果表明:用此方法可成功制备二维TiO2纳米网格,高温煅烧可以完全去除生物模板;TiO2纳米网格上形成了吸附较好的CdTe量子点,TiO2纳米网格比TiO2膜有更好的吸附性能。     

Scheduling jobs on parallel machines: a restricted tabu search approach

Many real scheduling problems are often much more complex than problems that are analytically tractable. The main difficulty in obtaining optimal job schedules arises from the existence of sequence dependent setup times among jobs and job release times. In this paper, we present a restricted tabu search algorithm that schedules jobs on parallel machines in order to minimise the maximum lateness of the jobs. The jobs have release times and due dates, and sequence-dependent setup times exist between the jobs. The parallel machines are either identical or non-identical in terms of the processing times of the jobs. The restricted tabu search algorithm employs a restricted search with the elimination of non-effective job moves, for finding the best neighbourhood schedule. The restricted search algorithm reduces search effort significantly while obtaining good quality final schedule. The experimental results show that the proposed algorithm obtains much better solutions more quickly than other heuristic algorithms such as the Rolling Horizon Procedure (RHP) heuristic, the basic tabu search and simulated annealing.     

基于工件聚类的并行机调度算法及其应用

针对纺织生产广泛存在的带工件释放时间、以最小化总拖期工件数和总拖期时间为目标的大规模并行机调度问题，提出一种基于工件聚类的遗传算法。该算法将求解过程分为工件聚类和工件排序两个阶段。在工件聚类阶段，基于影响并行机调度性能的重要调度特征量，采用改进的模糊C-均值聚类方法将所有待上机工件分为多个聚类；在工件排序阶段，采用基于规则编码的遗传算法，优化各聚类内工件的加工顺序。数值计算结果及实际应用效果表明，所提出的算法适用于求解带工件释放时间的大规模并行机调度问题。     

Development of autonomous mobile robot with manipulator for manufacturing environment

This paper describes the developmental effort involved in prototyping the first indigenous autonomous mobile robot, AMR, with a manipulator for carrying out tasks related to manufacturing. The objective is to design and develop a vehicle that can navigate autonomously and transport jobs and tools in a manufacturing environment. Proprioceptive and exteroceptive sensors are mounted on AMR for navigation. Among the exteroceptive sensors, a stereovision camera is mounted in front of AMR for mobile robot perception of the environment. Using the widely supported JPEG image file format, full high-resolution color images are transmitted frame by frame from the mobile robot to multiple viewers located within the robot work area, where fast reconstruction of these images enables remote viewing. A CMOS camera mounted on the manipulator identifies jobs for pick-and-place operation. A variation of correlation based adaptive predictive search (CAPS) method, a fast search algorithm in template matching, is used for job identification. The CAPS method justifiably selects a set of search steps rather than consecutive point-to-point search for faster job identification. Search steps, i.e., either coarse search or fine search, are selected by calculating the correlation coefficient between template and the image. Adaptive thresholding is used for image segmentation for parametric calculations required for proper gripping of the object. Communication with the external world allowing remote operation is maintained through wireless connectivity. It is shown that autonomous navigation requires synchronization of different processes in a distributed architecture, while concurrently maintaining the integrity of the network.     

基于ART1与BP神经网络的摩托车实例库检索系统的研究

针对传统摩托车设计过程中,设计人员为了找出合乎要求的相似车型,过多依赖经验,主观确定车型属性参数权重的问题,将人工神经网络理论和算法应用于摩托车实例库检索系统的研究中.通过ART1神经网络实现摩托车实例库的动态聚类,形成聚类模板,再利用前馈(BP)神经网络对模板中的每一实例进行检索.这种方法减小了车型属性权重中主观因素的影响,提高了系统的检索质量与效果,在实际应用中有良好的前景.     

Workflow balancing strategies in parallel machine scheduling

Workflow balancing on a shop floor helps to remove bottlenecks present in the manufacturing system. Workflow refers to the total time during which the work centres are busy. Idle time is not taken into account when calculating workflow. Earlier researchers have not specified the method for jobs to be executed in parallel in order to balance the workflow to each machine. In many manufacturing environments, multiple processing stations are used in parallel to obtain adequate capacity. In parallel machine scheduling there are m machines to which n jobs are to be assigned based on different priority strategies. The procedure is based on the idea of workload balancing and on balancing the workload among machines. In this paper, workflow and workload are assumed to have the same meaning. A machine with the lowest workflow is selected for assignment of a new job from the list of unfinished jobs. Different priority strategies are followed for the selection of jobs. Three different strategies are considered, namely random (RANDOM), shortest processing time (SPT) and longest processing time (LPT) for the selection of jobs for workflow balancing. The relative percentage of imbalance (RPI) is adopted among the parallel machines to evaluate the performance of these strategies in a standard manufacturing environment. The LPT rule shows better performance for the combination of larger job sizes and higher number of work centres or machines. A computer program was coded for validation in a standard manufacturing environment on an IBM/PC compatible system in the C++ language.     

Two-machine, no-wait job shop problem with separable setup times and single-server constraints

No-wait job shop scheduling problems refer to the set of problems in which a number of jobs are available for processing on a number of machines in a job shop context with the added constraint that there should be no waiting time between consecutive operations of the jobs. In this paper, a two-machine, no-wait job shop problem with separable setup times and a single-server constraint is considered. The considered performance measure is the makespan. This problem is strongly NP-hard. A mathematical model of the problem is developed and a number of propositions are proven for the special cases. Moreover, a genetic algorithm is proposed in this paper to find the optimal (or near-optimal) solutions. In order to evaluate the developed algorithm, a number of small instances are solved to optimality using the developed mathematical model. The proposed algorithm is able to find the optimal solution of all of these cases. For larger instances, the developed algorithm has been compared with the 2-opt algorithm as well as a proposed lower bound. Computational results show the efficiency of the proposed algorithm in generating good quality solutions compared to the developed lower bounds and 2-opt algorithm.     

基于并行结构的Gabor小波神经网络算法及应用

给出了一种基于并行结构的Gabor小波神经网络算法。根据多CPU系统的并行结构和神经网络本身并行性的特点,设计了用于图象目标识别的Gabor小波神经网络算法,算法的输入层包括Gabor小波尺度、平移和频率调制参数的运算;隐层是在并行CPU中实现神经网络算法及优化;输出层是Gabor小波神经网络的分类结果。对4类飞机图像目标进行了仿真实验,识别率达到98％以上,识别时间为40 ms。     

基于双重服务质量约束的网格资源调度策略

为提高网格资源利用率,以及用户对网格服务的满意程度,提出了基于双重服务质量约束的网格资源调度算法Senior.该算法在实现过程中,针对网格作业和资源的属性,通过具体化参数信息,推导出调度策略的模式;依据经典调度算法的相关思想,将任务完成期限和网络带宽确定为双重属性约束,并应用GridSim工具包对相关调度算法进行了测试.通过对仿真结果中的数据进行分析和比较,验证了新的调度算法Senior在解决类似问题时的优势.     

Scheduling algorithms for two-stage reentrant hybrid flow shops: minimizing makespan under the maximum allowable due dates

We consider the scheduling problem in hybrid flow shops that consist of two stages in series, each of which has multiple identical parallel machines. Each job has reentrant flow, i.e., the job visits each production stage several times. The problem is to determine the allocation of jobs to machines as well as the sequence of the jobs assigned to each machine for the objective of minimizing makespan subject to the maximum allowable due dates in the form of a constraint set with a certain allowance. To solve the problem, two types of algorithms are suggested: (a) a branch and bound algorithm that gives optimal semi-permutation schedules; and (b) heuristic algorithms that give non-permutation schedules. To show their performances, computational experiments were done on a number of test problems and the results are reported. In particular, one of the heuristics is competitive to the branch and bound algorithm with respect to the solution quality while requiring much shorter computation times.