排序方式: 共有51条查询结果,搜索用时 15 毫秒
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基于Vague集的装备采购项目组织结构评价方法 总被引:2,自引:0,他引:2
在装备采购项目组织评价中引入Vague集理论,在列举现有项目组织结构类型的基础上,构建项目组织结构评价指标体系,建立各项目组织结构和理想组织结构的Vague集,计算各项目组织结构和理想组织结构的相似度量,完成对装备采购项目组织结构的评价,为装备采购项目组织设计奠定基础。 相似文献
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粗糙集中不确定性测量的修正粗糙熵方法 总被引:1,自引:0,他引:1
分析了引起粗糙集中不确定性的因素,对已有的测量不确定性的粗糙度与粗糙熵方法进行了比较,提出了一种修正的粗糙熵方法,证明了此粗糙熵的性质,并将基于等价关系的修正粗糙熵拓展到基于一般二元关系下的广义修正粗糙熵,同时给出了广义修正粗糙熵的定义及性质.通过分析和实例可以看出,所提出的修正粗糙熵方法可以用来更合理、更精确地测量粗糙集中的不确定性. 相似文献
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海面目标运动和编队阵型的约束特性,使得通过对装订阵型和末制导探测阵型进行点集匹配来选择预定目标成为一种有效途径。但当编队目标释放干扰时,会引起阵型结构发生局部变化,导致目标选择性能恶化。本文基于反舰导弹目标选择需求,分析了传感器导航和探测误差、装订信息误差、编队目标运动和释放干扰等因素所引起的位置点集变形,通过利用阵型中未污染的结构信息,提出了基于几何散列法和结构加权平均Hausdorff距离的编队预定目标选择方法。理论分析和实验结果表明,该方法不受传感器导航误差和编队目标整体运动的影响,在编队存在冲淡干扰时能有效提高目标选择能力。 相似文献
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In the classical multiprocessor scheduling problem independent jobs must be assigned to parallel, identical machines with the objective of minimizing the makespan. This article explores the effect of assignment restrictions on the jobs for multiprocessor scheduling problems. This means that each job can only be processed on a specific subset of the machines. Particular attention is given to the case of processing times restricted to one of two values, 1 and λ, differing by at most 2. A matching based polynomial time ε‐approximation algorithm is developed that has a performance ratio tending to . This algorithm is shown to have the best possible performance, tending to 3/2, for processing times 1 and 2. For the special case of nested processing sets, i.e., when the sets of machines upon which individual jobs may be assigned are non‐overlapping, the behavior of list scheduling algorithms is explored. Finally, for assignment restrictions determined by just one characteristic of the machines, such as disc storage or memory constraint in the case of high performance computing, we contribute an algorithm that provides a 3/2 worst case bound and runs in time linear in the number of jobs. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2007 相似文献
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特征提取与评估是损伤检测和故障预测的基础。针对2K-H行星轮系缺齿损伤,建立了行星轮系的损伤模型,通过分析模型的仿真信号,提出了基于主频边带、小波变换和经验模式分解的多种损伤特征,并采用双样本一致性检验方法对所提取损伤特征的分类能力进行了评估,采用含噪声的仿真信号和试验数据对损伤特征进行了验证。验证结果表明,所提取的损伤特征均具有较强的分类能力,其中主频边带特征的分类性能最优。 相似文献
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针对粗糙集理论在有限个方案的多目标决策问题应用中存在的缺陷,提出了一种新的加权排序法,该方法既吸取了粗糙集约简属性的优点,又考虑到了各属性间的相对重要性,使得决策过程更符合实际情况.最后给出了该种排序法在武器装备系统论证中的应用,取得了较好的效果. 相似文献
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We study a generalization of the weighted set covering problem where every element needs to be covered multiple times. When no set contains more than two elements, we can solve the problem in polynomial time by solving a corresponding weighted perfect b‐matching problem. In general, we may use a polynomial‐time greedy heuristic similar to the one for the classical weighted set covering problem studied by D.S. Johnson [Approximation algorithms for combinatorial problems, J Comput Syst Sci 9 (1974), 256–278], L. Lovasz [On the ratio of optimal integral and fractional covers, Discrete Math 13 (1975), 383–390], and V. Chvatal [A greedy heuristic for the set‐covering problem, Math Oper Res 4(3) (1979), 233–235] to get an approximate solution for the problem. We find a worst‐case bound for the heuristic similar to that for the classical problem. In addition, we introduce a general type of probability distribution for the population of the problem instances and prove that the greedy heuristic is asymptotically optimal for instances drawn from such a distribution. We also conduct computational studies to compare solutions resulting from running the heuristic and from running the commercial integer programming solver CPLEX on problem instances drawn from a more specific type of distribution. The results clearly exemplify benefits of using the greedy heuristic when problem instances are large. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2005 相似文献
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