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951.
Although the concept of just-in-time (JIT) production systems has been proposed for over two decades, it is still important in real-world production systems. In this paper, we consider minimizing the total weighted earliness and tardiness with a restrictive common due date in a single machine environment, which has been proved as an NP-hard problem. Due to the complexity of the problem, metaheuristics, including simulated annealing, genetic algorithm, tabu search, among others, have been proposed for searching good solutions in reasonable computation times. In this paper, we propose a hybrid metaheuristic that uses tabu search within variable neighborhood search (VNS/TS). There are several distinctive features in the VNS/TS algorithm, including different ratio of the two neighborhoods, generating five points simultaneously in a neighborhood, implementation of the B/F local search, and combination of TS with VNS. By examining the 280 benchmark problem instances, the algorithm shows an excellent performance in not only the solution quality but also the computation time. The results obtained are better than those reported previously in the literature. 相似文献
952.
De-Nian Yang Wanjiun Liao 《Parallel and Distributed Systems, IEEE Transactions on》2007,18(11):1503-1515
In this paper, we propose a new multicast delivery mechanism for bandwidth-demanding applications in IP networks. Our mechanism, referred to as multiple-destination overlay multicast (MOM), combines the advantages of IP multicast and overlay multicast. We formulate the MOM routing problem as an optimization problem. We then design an algorithm based on Lagrangian relaxation on our formulation and propose a distributed protocol based on the algorithm. For network operators, MOM consumes less network bandwidth than both IP multicast and overlay multicast. For users, MOM uses less interface bandwidth than overlay multicast. 相似文献
953.
Decision support for risk analysis on dynamic alliance 总被引:4,自引:0,他引:4
Dynamic alliance has been considered a temporary organization of member enterprises formed to pool their core competencies and exploit fast changing market opportunities. Although many problems on dynamic alliance such as partner selection, operation management, information exchanges and their standards, etc., have been investigated, the risk management of dynamic alliance has not received deserved attention until now. For risk evaluation is the most important phase of risk management, so this paper is mainly concerned with the risk evaluation problem. Various kinds of risk factors that affect the operation of alliance are identified, and their levels are measured by three parameters such as risk occurrence likelihood, consequence severity and risk control degree. These parameters are expressed by trapezoidal fuzzy numbers. Furthermore, risk evaluation is regarded as a multiattribute decision-making (MADM) problem with uncertainty. A new evaluation approach based on the framework of the evidential reasoning (ER) is proposed. Finally, a numerical example is given to illustrate the application of this approach in the process of risk evaluation. 相似文献
954.
本文研究矩阵方程AXB=C在线性流形Γ={X∈SR~(n×n)|||TX-Y||=min}上的最佳逼近问题,得到了问题解的表达式.此外,还给出了求解该问题的数值算法和算例. 相似文献
955.
Based on the semi-group property of Chebyshev chaotic map and some effective improvements of our original protocol, we propose a novel chaotic maps-based key agreement protocol which is proved to be secure, feasible and extensible. 相似文献
956.
This paper presents a novel image watermark scheme based on the characteristics of amplitude attacks. First of all, the analysis of amplitude attacks is performed. Then the amplitude attacks are categorized into three types: positive attack, negative attack and random attack. Finally, based on these attack types, we design three corresponding detectors. The detectors remove the unreliable discrete cosine transform (DCT) coefficients in the attacked image so that only reliable coefficients are used for the extraction of the watermark embedded. The experimental results indicate that the proposed technique improves robustness significantly without sacrificing the false alarm rate. 相似文献
957.
958.
959.
选择典型的装有分体空调的居室和办公室,对多种新风不同引入方式下室内的环境参数作了测试,比较并分析了新风引入方式对室内热环境的影响,提出了采用低位大新风量高风速引入方式室内温度场不平均度最小,即温度环境最好,并对所得结果进行了的理论分析。 相似文献
960.
A novel autofocus algorithm for synthetic aperture radar (SAR) based on total variation is presented in this paper. The method,
which starts with a complex phasedegraded SAR image, after the phase errors model is introduced into the range-compressed
phase-history domain, carries out phase errors correction by changing the focus till the total variation of the azimuth profile
is maximized. Compared with the minimum entropy autofocus algorithm, the autofocus algorithm has less computational complexity
and is easier to implement. The simulation and the processing results of the measured data show the validity of the proposed
method.
Translated from Journal of Xidian University, 2006, 33(2): 167–172 [译自: 西安电子科技大学学报] 相似文献