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991.
992.
为解决单架无人机在城市环境中对辐射源目标的定位问题,提出了一种基于环境预测法的单无人机测向定位航迹优化算法。使用交互多模型-扩展卡尔曼滤波进行视距和非视距信号混合环境下的目标估计。结合估计的目标位置和城市地理信息模型,基于视线追踪法求解信号遮挡区域和多径信号干扰区域。在滚动时域控制算法框架下生成无人机预测轨迹,以最大化Fisher信息矩阵行列式为测向定位评价准则,考虑建筑物障碍以及其对信号的遮挡和反射效应对无人机测向定位航迹的影响,控制无人机选择最优航向飞行。仿真结果表明,该方法能够使无人机在存在障碍、信号遮挡和多径干扰的环境下实现对目标的高精度测向定位,为解决城市环境下的单架无人机测向定位问题提供了新思路。 相似文献
993.
Optimizing the selection of resources to accomplish a set of tasks involves evaluating the tradeoffs between the cost of maintaining the resources necessary to accomplish the tasks and the penalty cost associated with unfinished tasks. We consider the case where resources are categorized into types, and limits (capacity) are imposed on the number of each type that can be selected. The objective is to minimize the sum of penalty costs and resource costs. This problem has several practical applications including production planning, new product design, menu selection and inventory management. We develop a branch‐and‐bound algorithm to find exact solutions to the problem. To generate bounds, we utilize a dual ascent procedure which exploits the special structure of the problem. Information from the dual and recovered primal solutions are used to select branching variables. We generate strong valid inequalities and use them to fix other variables at each branching step. Results of tests performed on reasonably sized problems are presented. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 19–37, 1999 相似文献
994.
This article studies the inventory competition under yield uncertainty. Two firms with random yield compete for substitutable demand: If one firm suffers a stockout, which can be caused by yield failure, its unsatisfied customers may switch to its competitor. We first study the case in which two competing firms decide order quantities based on the exogenous reliability levels. The results from the traditional inventory competition are generalized to the case with yield uncertainty and we find that quantity and reliability can be complementary instruments in the competition. Furthermore, we allow the firms to endogenously improve their yield reliability before competing in quantity. We show that the reliability game is submodular under some assumptions. The results indicate that the competition in quantity can discourage the reliability improvement. With an extensive numerical study, we also demonstrate the robustness of our analytical results in more general settings. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 107–126, 2015 相似文献
995.
张金槐 《国防科技大学学报》1991,13(2):1-13
序贯验后加权检验方法是Bayes 统计观点在假设检验中的运用。本文提出了该方法的一般理论,给出了当总体的分布参数具有验前信息时的序贯检验方法。文中确定了决策区的划分,同时讨论了序贯截尾方案,给出了检验中可能犯两类错误的概率的上界,并将一般理论应用于产品的可靠性检验和再入飞行器随机落点的精度鉴定。由于运用了验前信息,因此能有效地在少量试验之下进行统计假设检验。本文所提供的方法对于昂贵产品试验结果的统计评定具有普遍意义。 相似文献
996.
针对运载火箭伺服机构故障,提出一种基于扩展多模型自适应估计的故障检测与诊断算法。建立考虑伺服机构故障的运载火箭姿态动力学模型;将故障角度作为状态变量得到增广状态空间模型;利用扩展卡尔曼滤波器进行状态向量和故障参数的非线性估计,并基于传感器测量数据采用假设检验算法在线计算故障发生的概率;给出基于扩展多模型自适应估计的故障检测与诊断算法流程。仿真结果表明,该方法在无故障时可对伺服机构进行健康监测;在单台伺服机构故障下,可以及时准确判断出哪一台芯级伺服机构发生故障,并可准确估计出伺服机构故障下的发动机摆角角度。 相似文献
997.
A new piece of equipment has been purchased in a lot of size m. Some of the items can be used in destructive testing before the item is put into use. Testing uncovers faults which can be removed from the remaining pieces of equipment in the lot. If t < m pieces of equipment are tested, then those that remain, m1 = m − t, have reduced fault incidence and are more reliable than initially, but m1 may be too small to be useful, or than is desirable. In this paper models are studied to address this question: given the lot size m, how to optimize by choice of t the effectiveness of the pieces of equipment remaining after the test. The models used are simplistic and illustrative; they can be straightforwardly improved. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 623–637, 1997 相似文献
998.
军事装备系统可靠性设计分析 总被引:1,自引:0,他引:1
军事装备系统是决定战争胜负的关键因素之一,装备系统的可靠性直接决定装备系统效能的发挥。军事装备系统的可靠性定量分析结果,是军事装备系统进行可靠性设计的重要依据。本文利用系统工程的理论,结合军事装备系统特殊要求,定量的分析了装备系统可靠性模型,提出了增强装备系统可靠性的设计方法。 相似文献
999.
1000.