空空导弹后射火控技术

对空空导弹后射火控技术进行了分析,重点讨论了后射中的导弹控制问题。由于在后射过程中的速度过零阶段,导弹的气动力无法提供足够的法向控制力,给出了气动力/推力矢量控制相结合的复合控制方案,并以此导弹控制模型实现了后射火控过程。通过数字仿真,比较了后射火控与越肩发射火控的不同攻击过程,表明所提出的导弹复合控制方案可以解决导弹后射火控问题,后射与越肩发射相结合可以更好地实现全向攻击。     

A comparative study of three tool replacement/operation sequencing strategies in a flexible manufacturing system

This paper studies three tool replacement/operation sequencing strategies for a flexible manufacturing system over a finite time horizon: (1) failure replacement—replace the tool only upon failure, (2) optimal preventive tool replacement for a fixed sequence of operations, and (3) joint scheduling of the optimal preventive tool replacement times and the optimal sequence of operations. Stochastic dynamic decision models are used for strategies 2 and 3. The optimization criterion for strategies 2 and 3 is the minimization of the total expected cost over the finite time horizon. We will show through numerical studies that, with the same amount of information, the total expected costs can be reduced considerably by choosing an optimal strategy. Our conclusion is that in flexible manufacturing, optimal tool replacement and optimal operations sequencing are not separate issues. They should be considered jointly to minimize the expected total cost. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 479–499, 2000     

The LP/POMDP marriage: Optimization with imperfect information

A new technique for solving large‐scale allocation problems with partially observable states and constrained action and observation resources is introduced. The technique uses a master linear program (LP) to determine allocations among a set of control policies, and uses partially observable Markov decision processes (POMDPs) to determine improving policies using dual prices from the master LP. An application is made to a military problem where aircraft attack targets in a sequence of stages, with information acquired in one stage being used to plan attacks in the next. © 2000 John Wiley & Sons, Inc., Naval Research Logistics 47: 607–619, 2000     

前苏联发展反卫星武器的回顾

随着军用卫星的种类变化和性能提高 ,以及为谋求外层空间作战的军事优势 ,前苏联一直在积极发展反卫星武器。介绍了前苏联反卫星武器的组成、特点、技术方案及其发展情况 ,最后归纳了关于前苏联反卫星武器的几点看法。     

BP神经网络的收敛问题

研究了BP神经网络的收敛问题。基于随机理论 ,提出了解决网络收敛性问题的随机优选法。该方法不仅在任何条件下都能得到问题的具有一定精度的解答 ,而且收敛速度很快     

Optimal nonmyopic gambling strategy for the generalized Kelly criterion

We consider the optimal wagers to be made by a gambler who starts with a given initial wealth. The gambler faces a sequence of two-outcome games, i.e., “win” vs. “lose,” and wishes to maximize the expected value of his terminal utility. It has been shown by Kelly, Bellman, and others that if the terminal utility is of the form log x, where x is the terminal wealth, then the optimal policy is myopic, i.e., the optimal wager is always to bet a constant fraction of the wealth provided that the probability of winning exceeds the probability of losing. In this paper we provide a critique of the simple logarithmic assumption for the utility of terminal wealth and solve the problem with a more general utility function. We show that in the general case, the optimal policy is not myopic, and we provide analytic expressions for optimal wager decisions in terms of the problem parameters. We also provide conditions under which the optimal policy reduces to the simple myopic case. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 639–654, 1997     

基于遗传算法的MIL-STD-188-220c标准最佳转发树的构造

针对MIL-STD-188-220C标准的路由协议多目的地址最佳转发树问题,提出一种基于遗传算法的优化算法,仿真结果表明,该算法具有收敛快,寻路成功率高的优点。     

Optimal inventory and dynamic admission policies for a retailer of seasonal products with affiliate programs and drop‐shipping

This article investigates the optimal inventory and admission policies for a “Clicks‐and‐Bricks” retailer of seasonal products that, in addition to selling through its own physical and online stores, also sells through third‐party websites by means of affiliate programs. Through postings on partners' webpages, an affiliate program allows a retailer to attract customers who would otherwise be missed. However, this retailer needs to pay a commission for each sale that originates from the website operators participating in the program. The retailer may also refer online orders to other sources (such as distributors and manufacturers) for fulfillment through a drop‐shipping agreement and thus earns commissions. This would be an option when, for example, the inventories at the physical stores were running low. Therefore, during the selling horizon, the retailer needs to dynamically control the opening/closing of affiliate programs and decide on the fulfillment option for online orders. On the basis of a discrete‐time dynamic programming model, the optimal admission policy of the retailer is investigated in this paper, and the structural properties of the revenue function are characterized. Numerical examples are given to show the revenue impact of optimal admission control. The optimal initial stocking decisions at the physical stores are also studied. © 2009 Wiley Periodicals, Inc. Naval Research Logistics 2009     

自旋稳定动能拦截器轨控发动机推力控制

提出了大气层外自旋稳定式动能拦截器的一种典型轨控发动机阵列布局.在分析小发动机工作的各种约束条件的基础上,推导了发动机推力角度、推力大小和冲量效率的计算公式,提出了发动机工作的控制方法.在各种初始条件下进行拦截仿真,所得的脱靶量均在0.3 m以内,可视为直接碰撞命中目标.同时通过仿真分析了冲量效率与自旋速度、发动机工作时间、每圈发动机个数的关系.     

基于内外子区域划分的高阶精度CFD程序异构并行算法

对计算流体力学(CFD)程序CNS提出一种Offload模式下基于内外子区域划分的异构并行算法,结合结构化网格下有限差分计算和四阶龙格库塔方法的特点,引入ghost网格点区域,设计了一种ghost区域收缩计算策略,显著降低了异构计算资源之间的数据传输开销,负载均衡时CPU端的计算与MPI通信完全和加速器端的计算重叠,提高了异构协同并行性。推导了保证计算正确性的ghost区域的参数,分析了负载均衡的条件。在“CPU(Intel Haswell Xeon E5-2670 12 cores ×2)＋加速器(Xeon Phi 7120A ×2)”的服务器上测得该算法较直接将任务子块整体迁至加速器端计算的异构算法性能平均提升5.9倍,较MPI/OpenMP两级并行算法使用24个纯CPU核的性能,该算法使用单加速器时加速1.27倍,使用双加速器加速1.45倍。讨论和分析了性能瓶颈与存在的问题。