We consider the problem of finding semi-matching in bipartite graphs, which is also extensively studied under various names in the scheduling literature. We give faster algorithms for both weighted and unweighted case...
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We consider the problem of finding semi-matching in bipartite graphs, which is also extensively studied under various names in the scheduling literature. We give faster algorithms for both weighted and unweighted cases. For the weighted case, we give an O(nmlog n)-time algorithm, where n is the number of vertices and ni is the number of edges, by exploiting the geometric structure of the problem. This improves the classical O(n(3))-time algorithms by Horn [1973] and Bruno et al. [1974b]. For the unweighted case, the bound can be improved even further. We give a simple divide-and-conquer algorithm that runs in O(root nmlog n) time, improving two previous O(nm)-time algorithms by Abraham [2003] and Harvey et al. [2003, 20061. We also extend this algorithm to solve the Balanced Edge Cover problem in O(root nmlog n) time, improving the previous O(nm)-time algorithm by Harada et al. [2008].
In this paper, we investigate the capacitated two-parallel machines scheduling problem, where one machine is only available for a special period of time after which it can no longer process any job while the other mac...
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In this paper, we investigate the capacitated two-parallel machines scheduling problem, where one machine is only available for a special period of time after which it can no longer process any job while the other machine is continuously available. Our objective is to minimize the completion time of the machine which is continuously available. The offline version of the problem is equivalent to the minimization version of the Subset-Sum problem. We first show the lower bound of the online version is infinite. We also consider the semi-online version with known the total job processing time in advance, for which both lower bound and semi-online algorithms are given.
Machine scheduling and covering problems may occur in many applications such as load balancing in network communication channel assignment, parallel processing in large-size computing, task arrangement in flexible man...
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Machine scheduling and covering problems may occur in many applications such as load balancing in network communication channel assignment, parallel processing in large-size computing, task arrangement in flexible manufacturing systems, etc. In this paper we study machine covering problems with combined partial information on m parallel identical machines. We consider sequences where the processing time of all jobs are at most 1/k times of the optimal value (for an integer k). For the case where the optimal value is not known in advance, we show that IS algorithm is optimal. For the case where the optimal value is known in advance, we give lower bounds and present semi-online algorithms. (C) 2010 Elsevier B.V. All rights reserved.
This paper investigates the problem of semi-online scheduling on three parallel identical machines with non-simultaneous machine available times. We prove that if the total processing time of all jobs and the largest ...
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ISBN:
(纸本)9781846260667
This paper investigates the problem of semi-online scheduling on three parallel identical machines with non-simultaneous machine available times. We prove that if the total processing time of all jobs and the largest processing time of all jobs are both known in advance, the competitive ratio of the optimal algorithm is 3 / 2.
This paper studies online scheduling problems with reassignment on two identical machines. We can reassign some jobs under certain rules after all the jobs have been assigned. Three different versions are studied and ...
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This paper studies online scheduling problems with reassignment on two identical machines. We can reassign some jobs under certain rules after all the jobs have been assigned. Three different versions are studied and optimal algorithms are proposed. (C) 2007 Elsevier B.V. All rights reserved.
This paper addresses linear time algorithms for parallel machine scheduling problems. We introduce a kind of threshold algorithms and discuss their main features. Three linear time threshold algorithm classes DT, PT a...
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This paper addresses linear time algorithms for parallel machine scheduling problems. We introduce a kind of threshold algorithms and discuss their main features. Three linear time threshold algorithm classes DT, PT and DTm are studied thoroughly. For all classes, we study their best possible algorithms among each class. We also present their application to several scheduling problems, The new algorithms are better than classical algorithms in time complexity and/or worst-case ratio. Computer-aided proof technique is used in the proof of main results, which greatly simplifies the proof and decreases case by case analysis.
This paper investigates the semi-online scheduling problem with the known largest size on two uniform machines. The objective is to maximize the minimum machine completion time. Both lower bounds and algorithms are gi...
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This paper investigates the semi-online scheduling problem with the known largest size on two uniform machines. The objective is to maximize the minimum machine completion time. Both lower bounds and algorithms are given. algorithms are optimal for the majority values of s≥1, where s is the speed ratio of the two machines. The largest gap between the competitive ratio and the lower bound is about 0.064. Moreover, the overall competitive ratio 2 matches the overall lower bound.
This paper investigates semi-online scheduling problem with known total size on two uniform machines for maximizing the minimum machine completion time. Lower bounds and optimal algorithms for every s >= 1 are give...
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This paper investigates semi-online scheduling problem with known total size on two uniform machines for maximizing the minimum machine completion time. Lower bounds and optimal algorithms for every s >= 1 are given, where s is the speed ratio of two machines. Both the overall competitive ratio and the competitive ratio for s>1+root 5/2 are strictly smaller than those of the optimal algorithms of the corresponding semi-online scheduling problem with known optimal value. It indicates that two related semi-online problems are different.
In this paper, a sequential algorithm is presented to find all cut-vertices on trapezoid graphs. To every trapezoid graph G there is a corresponding trapezoid representation. If all the 4n corner points of n trapezoid...
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In this paper, a sequential algorithm is presented to find all cut-vertices on trapezoid graphs. To every trapezoid graph G there is a corresponding trapezoid representation. If all the 4n corner points of n trapezoids, in a trapezoid representation of a trapezoid graph G with n vertices, are given, then the proposed sequential algorithm runs in O(n) time. Parallel implementation of this algorithm can be done in O( log n) time using O(n/log n) processors on an EREW PRAM model.
Focusing on the ordinal scheduling problem on a parallel machine system, we discuss the background of ordinal scheduling and the motivation of ordinal algorithms. In addition, for the ordinal scheduling problem on ide...
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Focusing on the ordinal scheduling problem on a parallel machine system, we discuss the background of ordinal scheduling and the motivation of ordinal algorithms. In addition, for the ordinal scheduling problem on identical parallel machines with the objective to maximize the minimum machine load, we then give two asymptotically optimal algorithm classes which have worst-case ratios very close to the upper bound of the problem for any given m. These results greatly improve the results proposed by He Yong and Tan Zhiyi in 2002.
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