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1.
In this paper, a single-machine scheduling model with a given common due date is considered. Job processing time is a linear decreasing function of its starting time. The objective function is to minimize the total weighted earliness award and tardiness penalty. Our aim is to find an optimal schedule so as to minimize the objective function. As the problem is NP-hard, some properties and polynomial time solvable cases of this problem are given. A dynamic programming algorithm for the general case of the problem is provided.  相似文献   

2.
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   

3.
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   

4.
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   

5.
INTRODUCTION Scheduling problems have been studied widely in recent years with many results. In the classical scheduling problems, the processing times of jobs are constant, although, there are many cases where the processing times of jobs are not constant but in- creasing or decreasing over time so that the process- ing times of jobs are no longer independent. For example, a facility is deteriorating because of long time use so that its processing capacity de- creases with time, and a job…  相似文献   

6.
We consider a scheduling problem involving a single processor utilized by two customers with constant deteriorating jobs,i.e.,jobs whose processing times are an increasing function of their starting times.Traditionally,such scenarios are modeled by assuming that each customer has the same criterion.In practice,this assumption may not hold.Instead of using a single criterion,we examine the implications of minimizing an aggregate scheduling objective function in which jobs belonging to different customers are evaluated with their individual criteria.We examine three basic scheduling criteria:minimizing makespan,minimizing maximum lateness,and minimizing total weighted completion time.We demonstrate all the scheduling problems considered are polynomially solvable.  相似文献   

7.
混流车间作业调度是实际生产环节中的一个重要问题,也是制造系统生产管理的核心,同时实际的生产系统是一个动态生产环境.文中提出蚁群动态调度算法,通过实例具体分析并且跟传统的启发式算法相比较,实验结果证明蚁群动态调度算法对混流车间作业调度问题有较优的加工路径.  相似文献   

8.
关于最优流水作业调度问题有多种实现算法,阐述了利用动态规划算法解决满足Johnson法则的最优作业调度问题,并且对不同的算法进行了比较和分析.  相似文献   

9.
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   

10.
This paper considers a reentrant scheduling problem on parallel primary machines with a remote server machine, which is required to carry out the setup operation. In this problem, each job has three operations. The first and last operations are performed by the same primary machine, implying the reentrance, and the second operation is processed on the single server machine. The order of jobs is predetermined in our context. The challenge is to assign jobs to the primary machines to minimize the makespan. We develop a genetic algorithm(GA) to solve this problem. Based on a simple strategy of assigning jobs in batches on the parallel primary machines, the standardized random key vector representation is employed to split the jobs into batches. Comparisons among the proposed algorithm, the branch and bound(BB) algorithm and the heuristic algorithm, coordinated scheduling(CS), which is only one heuristic algorithm to solve this problem in the literature, are made on the benchmark data. The computational experiments show that the proposed genetic algorithm outperforms the heuristic CS and the maximum relative improvement rate in the makespan is 1.66%.  相似文献   

11.
主要研究了一种带拒绝费用的排序问题。目标函数是在不超过总拒绝费用阀值的前提下使最大完工时间最小。首先,证明了该问题是N P-难的;然后我们针对这个问题设计出了伪多项式时间的动态规划算法,并给出了FPTAS。  相似文献   

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