An exact analysis of a joint production‐inventory problem in two‐echelon inventory systems

We consider a two‐echelon inventory system with a manufacturer operating from a warehouse supplying multiple distribution centers (DCs) that satisfy the demand originating from multiple sources. The manufacturer has a finite production capacity and production times are stochastic. Demand from each source follows an independent Poisson process. We assume that the transportation times between the warehouse and DCs may be positive which may require keeping inventory at both the warehouse and DCs. Inventory in both echelons is managed using the base‐stock policy. Each demand source can procure the product from one or more DCs, each incurring a different fulfilment cost. The objective is to determine the optimal base‐stock levels at the warehouse and DCs as well as the assignment of the demand sources to the DCs so that the sum of inventory holding, backlog, and transportation costs is minimized. We obtain a simple equation for finding the optimal base‐stock level at each DC and an upper bound for the optimal base‐stock level at the warehouse. We demonstrate several managerial insights including that the demand from each source is optimally fulfilled entirely from a single distribution center, and as the system's utilization approaches 1, the optimal base‐stock level increases in the transportation time at a rate equal to the demand rate arriving at the DC. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

On the optimal detection of an underwater intruder in a channel using unmanned underwater vehicles

Given a number of patrollers that are required to detect an intruder in a channel, the channel patrol problem consists of determining the periodic trajectories that the patrollers must trace out so as to maximized the probability of detection of the intruder. We formulate this problem as an optimal control problem. We assume that the patrollers' sensors are imperfect and that their motions are subject to turn‐rate constraints, and that the intruder travels straight down a channel with constant speed. Using discretization of time and space, we approximate the optimal control problem with a large‐scale nonlinear programming problem which we solve to obtain an approximately stationary solution and a corresponding optimized trajectory for each patroller. In numerical tests for one, two, and three underwater patrollers, an underwater intruder, different trajectory constraints, several intruder speeds and other specific parameter choices, we obtain new insight—not easily obtained using simply geometric calculations—into efficient patrol trajectory design under certain conditions for multiple patrollers in a narrow channel where interaction between the patrollers is unavoidable due to their limited turn rate.© 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

利用惯导信息的反舰末制导雷达抗干扰方法

惯导信息短期精度高、稳定性好,且自主工作,不受外界电磁干扰.基于惯导的这些特点,提出了一种利用惯导位置、速度信息辅助抗舷外干扰的信息处理方法:在反舰导弹末制导跟踪阶段,建立弹目相对运动模型,通过扩展卡尔曼滤波降低雷达导引头随机测量误差,获取目标位置和速度信息,当检测到干扰,通过对目标位置的预测和惯导对导弹位置的确定,实...     

电视侦察弹侦察效力的演化仿真优化研究

为了保证电视侦察弹能到达目标区域的上空并发挥最优的侦察效力,采用了基于遗传算法的启发式仿真优化方法来解决炮射电视侦察弹的优化使用问题.分析了电视侦察弹的主要影响因素,建立了用于计算目标侦察效力的仿真模型,引入了演化策略,实现了基于进化计算的启发式仿真优化系统,并求取了电视侦察弹的最大侦察效力及其主要影响因素的最优搭配....     

MARK XIIA Mode 5系统仿真及抗干扰性能分析

Mark XIIA Mode 5是美军及北约盟军用以提高态势感知能力的新型敌我识别系统。以其为研究对象,首先分析了它所应用的关键技术,如RS纠错编码、软扩频和MSK调制等新技术;其次根据所应用的关键技术对系统进行了模型构建,并以Matlab为仿真平台进行了仿真,得出了询问/应答信号的时域波形及频谱;最后,重点对系统的抗干扰性能进行了分析,分别得出了MSK解调后、解扩后和RS解码后的误码率曲线,可以看出Mark XIIA Mode 5具有很强的抗干扰性能。     

基于遗传算法的防空兵群最优火力分配模型研究

结合战场目标价值分析,根据防空兵火力分配情况,运用遗传算法建立了最佳火力分配模型,使防空武器最大限度的发挥火力单位效能,达到最大毁伤效果。采用了实数编码方案,对选择,交叉,变异等操作进行了改进。最后通过计算,验证了方案的可行性和优越性.     

对抗仿真中防空导弹微分对策模型研究

针对防空导弹与目标的空间对抗,建立了防空导弹微分对策空间对抗模型,并推算得到了最优策略,运用自适应神经网络评判方法对模型进行求解,通过给定条件下的仿真证明了该算法的有效性,显示了该模型可应用于防空导弹与目标的空间对抗问题。     

纯方位系统定位与跟踪的本载体最优轨线方程及其最优轨线

给出了纯方位系统在目标任意变速变向运动或不动情况下,目标定位与跟踪中的本载体确定性控制最优和次优轨线方程以及其最优轨线。这一结果是完全用解析方法得到的。     

On optimality of one‐bug‐look‐ahead policies for a software testing model

The optimality of the One‐Bug‐Look‐Ahead (OLA) software release policy proposed by Morali and Soyer ( 15 ) is re‐examined in this paper. A counterexample is constructed to show that OLA is not optimal in general. The optimal stopping approach is then called upon to prove that OLA possesses weaker sense of optimality under conditional monotonicity and the strong sense of optimality holds under a more restrictive sample‐wise monotonicity condition. The NTDS data are analyzed for illustration, and OLA is shown to be robust with respect to model parameters. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007.     

一种多约束条件下高超声速导弹对地攻击的三维最优变结构制导律

针对高超声速空地导弹多约束高精度末制导的基本需求,在三维解耦的俯仰平面和转弯平面上分别设计制导律。在综合考虑脱靶量、落角、入射角等多种约束条件后,运用最优控制构造的最优制导律设计了一种三维最优变结构制导律,接着利用梯度自适应下降法和T-S模型改进了速度约束控制。最后通过典型弹道的结果显示该制导律能够满足多约束高精度制导的需要,具有良好的弹道性能。