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1.
关于简单线性恶化问题的平行机排序的一个全多项式逼近算法 总被引：1，自引：0，他引：1
In this paper, a parallel machine scheduling problem was considered , where the processing time of a job is a simple linear function of its starting time. The objective is to minimize makespan. A fully polynomial time approximation scheme for the problem of scheduling n deteriorating jobs on two identical machines was worked out. Furthermore, the result was generalized to the case of a fixed number of machines. 相似文献
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In this paper we consider an online scheduling of parallel jobs with preemption on identical machines, where jobs arrive over time. The objective is to minimize the makespan. For the problem that jobs have only two possible widths mj = 1 or m, we present an optimal online algorithm by using ＂temporary schedule＂. 相似文献
3.
Ehsan Ullah Munir Jian-zhong Li Sheng-fei Shi Zhao-nian Zou Qaisar Rasool 《浙江大学学报(A卷英文版)》2008,9(12):1715-1723
Heterogeneous computing （HC） environment utilizes diverse resources with different computational capabilities to solve computing-intensive applications having diverse computational requirements and constraints. The task assignment problem in HC environment can be formally defined as for a given set of tasks and machines, assigning tasks to machines to achieve the minimum makespan. In this paper we propose a new task scheduling heuristic, high standard deviation first （HSTDF）, which considers the standard deviation of the expected execution time of a task as a selection criterion. Standard deviation of the expected execution time of a task represents the amount of variation in task execution time on different machines. Our conclusion is that tasks having high standard deviation must be assigned first for scheduling. A large number of experiments were carried out to check the effectiveness of the proposed heuristic in different scenarios, and the comparison with the existing heuristics （Max-min, Sufferage, Segmented Min-average, Segmented Min-min, and Segmented Max-min） clearly reveals that the proposed heuristic outperforms all existing heuristics in terms of average makespan. 相似文献
4.
HAN Shu-guang JIANG Yi-wei HU Jue-liang 《浙江大学学报(A卷英文版)》2007,8(1):127-133
INTRODUCTION In this paper we investigate the uniform ma-chines scheduling problem with machine activationcost. This problem has application in garment pro-duction of international trade and is motivated by thefollowing scenario. Import-export company is com-pared to scheduler in this model, and orders are jobs,which arrive one by one. And garment factories canbe regarded as machines. Since jobs should be fin-ished on time, scheduler will choose a reasonablenumber of machines to make the… 相似文献
5.
Optimal online algorithms for scheduling on two identical machines under a grade of service 总被引：8，自引：0，他引：8
INTRODUCTIONWe study the problem of online scheduling on two identical parallel machines with a new feature that service requests from various customers are entitled to many different grade of service (GoS) levels. The goal is to minimize the makespan under the constraint that all requests are satisfied. This problem was first proposed by Hwang et al.(2004) and is motivated by the following scenario. In the service industry, the service providers often have special customers, such as, go… 相似文献
6.
研究预防性周期维护策略下再制造系统中可中断和不可中断2类工件的单机调度问题.以最小化完工时间为目标,提出了LPT-LS算法,该算法首先按LPT(longest processing time)规则安排不可中断工件,然后按LS(list scheduling)规则安排可中断工件.并根据可中断工件的总加工时间(记为S2)分3种情况证明了该算法的最坏情况比,结论如下:当S2大于按LPT规则安排不可中断工件后机器的空闲时间时,最坏情况比为1;当S2介于分别按LPT规则和OPT(最优排序)规则安排不可中断工件后机器的空闲时间之间时,最坏情况比小于2;当S2小于按OPT规则安排不可中断工件后机器的空闲时间时,最坏情况比小于2.最后通过算例验证了结论的正确性. 相似文献
7.
黄宜坤 《临沂师范学院学报》2006,28(6):20-23
主要研究关于工件加工时间恶化的若干问题,给出了最大完工时间问题的一些性质、总完工时间问题的算法和性质,并根据实际问题,设计了一些新模型,相应地给出了该问题所具有的性质及一些简单算法． 相似文献
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在现代生产管理中,合理安排工件的加工顺序使所有的工件准时完工极为重要．文中研究工件不允许拖期的单机分批调度问题,目标是使加工．总成本最小,目标函数不仅考虑了工件提前完工有提前惩罚成本,还考虑了批加工成本费用．提出了一种多项式时间的最优算法． 相似文献
10.
The permutation flow shop scheduling problems with deteriorating jobs and rejection on dominant machines were studied. The objectives are to minimize the makespan of scheduled jobs plus the total rejection penalty and the total completion time of scheduled jobs plus the total rejection penalty. For each objective, polynomial time algorithms based on dynamic programming were presented. 相似文献
11.
官春平 《广东轻工职业技术学院学报》2008,7(2):9-12
在柔性作业车间调度问题模型的基础上,针对资源约束作业车间调度问题及多目标柔性作业车间调度结合的问题,建立了资源约束下多目标柔性作业车间调度问题的数学模型,提出了启发式活动调度算法与遗传算法结合来对模型进行求解。选择操作采用轮盘赌选择方式;交叉操作采用基于活动启发式算法的交叉算子;变异操作采用基于领域搜索的变异。最后分析了一个具体调度结果实例。 相似文献
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为了研究更具实际意义的带有位置依赖影响的分组调度决策问题,建立了一般性位置依赖的分组调度模型.在模型中,分组实际发动时间和工件的实际加工时间被表示成初始时间和调度位置的一般函数.此类函数没有被假设为特殊函数形式,且没有要求限制其函数单调性.通过数理逻辑分析和证明,把所研究的问题模型分解为组调度过程和工件调度过程,并把每个调度过程分别转化为经典任务分派问题和单机排序调度问题,进而分析问题求解的计算复杂度.研究表明,即使在一般性位置依赖的模型假设下,单机最小化时间表长的分组调度问题和平行机最小化总负荷的分组调度问题仍然是多项式可解的. 相似文献
13.
考虑了两台同类机极小化总完工时间的分批排序问题,给出了计算复杂性为O(n3)的动态规划算法,并将此算法推广到了工件具有学习效应的情况. 相似文献
14.
A single machine scheduling problem involving fuzzy due dates and fuzzy precedence constraints is investigated. The fuzzy precedence reflects the satisfaction level with respect to precedence between two jobs. A membership function is associated with each job Ji, which describes the degree of satisfaction with respect to completion time of Ji. For the bi-criteria scheduling problem, an 0 （ n^3 ） algorithm is proposed for finding nondominated solutions. 相似文献
15.
The combination of online or semi-online with deterioration jobs has never been researched in scheduling problems. In this paper, two semi-online parallel machine scheduling problems with linear deterioration processing time are considered. In the first problem, it is assumed that the deterioration rates of jobs are known in an interval, that is, bj ∈[0, α], where 0 〈α≤ 1 and bj denotes the linear deterioration rate. In the second problem, it is assumed that the largest deterioration rate of jobs is known in advance, that is, b = max1≤j≤n {bj }. For each of the two problems, a heuristic MBLS algorithm is worked out and its worst-case ratio is analyzed. At the same time, the worst-case ratio of the list （LS） algorithm is investigated and it is proved that all the ratios are tight. 相似文献
16.
王继群 《北京工业职业技术学院学报》2006,5(3)
数控机床在程序传输和程序管理方面存在操作方法复杂,运作混乱等弊端,解决此问题的最好的方法就是将数控机床联网.这里介绍了数控机床联网系统的结构及主要功能,应用实例对机床联网前后的变化进行比较,阐述了对数控设备进行联网的重要性. 相似文献
17.
In this paper,a fabrication scheduling problem concerning the production of components at a single manufacturing facility was studied,in which the manufactured components are subsequently assembled into a finite number of end products. Each product was assumed to comprise a common component to all jobs and a unique component to itself.Common operations were processed in batches and each batch required a setup time.A product is completed when both its two operations have been processed and are available.The optimality criterion considered was the minimization of weighted flow time.For this scheduling problem,the optimal schedules were described in a weignted shortest processing time first(WSPT)order and two algorithms were constructed corresponding to the batch availability and item availability,respectively. 相似文献
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本文考虑带有固定工件的一个单机排序问题,证明了该问题是NP-困难的并给出了它的一个动态规划算法,证明该问题是拟多项式时间可解的。 相似文献
20.
有效地混合了遗传算法和基于约束满足的自适应神经网络算法,对于一类加工时间可变的调度问题进行了研究.遗传算法被用来进行迭代寻优.当前代经交叉和变异后生成的染色体对应非可行解,由自适应神经网络运算后得到可行解,对应的染色体作为新一代染色体.本算例的目标函数是基于任务的提前/拖期惩罚、附加惩罚以及加工时间的偏离量惩罚,目标是确定最优加工时间和最优加工顺序极小化目标函数,并与一般的遗传算法相比较,实验结果说明了遗传/自适应神经网络算法混合算法的有效性. 相似文献