Optimal FCFS allocation rules for periodic‐review assemble‐to‐order systems

In Assemble‐To‐Order (ATO) systems, situations may arise in which customer demand must be backlogged due to a shortage of some components, leaving available stock of other components unused. Such unused component stock is called remnant stock. Remnant stock is a consequence of both component ordering decisions and decisions regarding allocation of components to end‐product demand. In this article, we examine periodic‐review ATO systems under linear holding and backlogging costs with a component installation stock policy and a First‐Come‐First‐Served (FCFS) allocation policy. We show that the FCFS allocation policy decouples the problem of optimal component allocation over time into deterministic period‐by‐period optimal component allocation problems. We denote the optimal allocation of components to end‐product demand as multimatching. We solve the multi‐matching problem by an iterative algorithm. In addition, an approximation scheme for the joint replenishment and allocation optimization problem with both upper and lower bounds is proposed. Numerical experiments for base‐stock component replenishment policies show that under optimal base‐stock policies and optimal allocation, remnant stock holding costs must be taken into account. Finally, joint optimization incorporating optimal FCFS component allocation is valuable because it provides a benchmark against which heuristic methods can be compared. © 2015 Wiley Periodicals, Inc. Naval Research Logistics 62: 158–169, 2015     

基于阶次分析方法的齿轮箱齿轮故障诊断研究

研究了旋转机械非稳态振动信号分析中的计算阶次分析方法．分析了该方法在重采样过程中的采样率设置规则．利用插值算法实现了对等时间间隔采样的齿轮箱振动信号的角域重采样,将其应用于齿轮箱加速过程故障诊断,成功识别了齿面磨损故障．结果显示,阶次分析法能有效避免传统频谱方法出现的频率模糊现象,在处理非平稳转速变化信号时具有独特的优越性．     

基于免疫遗传算法的人上位拣选车作业规划问题求解

针对人上位拣选车的作业轨迹规划问题构建了具有附加安全约束条件的时间最优控制数学模型,并提出了一种免疫遗传求解算法．该算法较单纯遗传算法有效避免了种群退化,且收敛速度更快．实验表明,该算法适用于求解人上位拣选车的作业轨迹规划问题．     

超声速导弹的光滑二阶滑模控制器设计

建立了带有气动系数不确定量和外界干扰的超声速导弹的运动模型。采用输出重定义技术克服了导弹过载输出的非最小相位特性,利用容易测量的过载和角速度相组合重新定义了新输出量。为了削弱滑模控制的颤振影响,同时又保持滑模控制的强鲁棒性,采用光滑二阶滑模控制方法设计了导弹过载控制系统中的控制器。设计了二阶滑模观测器对汇总不确定量进行有效估计。为了检验所设计的观测器和控制器的控制效果,仿真分析中对比了光滑二阶滑模控制器和传统滑模控制器的仿真结果。仿真结果表明：光滑二阶滑模控制器能够有效地削弱颤振影响,使导弹过载输出快速准确地跟踪上过载指令信号。     

Exact algorithms for integrated facility location and production planning problems

We consider a class of facility location problems with a time dimension, which requires assigning every customer to a supply facility in each of a finite number of periods. Each facility must meet all assigned customer demand in every period at a minimum cost via its production and inventory decisions. We provide exact branch‐and‐price algorithms for this class of problems and several important variants. The corresponding pricing problem takes the form of an interesting class of production planning and order selection problems. This problem class requires selecting a set of orders that maximizes profit, defined as the revenue from selected orders minus production‐planning‐related costs incurred in fulfilling the selected orders. We provide polynomial‐time dynamic programming algorithms for this class of pricing problems, as well as for generalizations thereof. Computational testing indicates the advantage of our branch‐and‐price algorithm over various approaches that use commercial software packages. These tests also highlight the significant cost savings possible from integrating location with production and inventory decisions and demonstrate that the problem is rather insensitive to forecast errors associated with the demand streams. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

A note on necessary and sufficient conditions for ordering properties of coherent systems with exchangeable components

We give necessary and sufficient conditions based on signatures to obtain distribution‐free stochastic ordering properties for coherent systems with exchangeable components. Specifically, we consider the stochastic, the hazard (failure) rate, the reversed hazard rate, and the likelihood ratio orders. We apply these results to obtain stochastic ordering properties for all the coherent systems with five or less exchangeable components. Our results extend some preceding results. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

基于统计的网络化指挥控制系统拓扑模型

灵活、安全、高效的拓扑是网络化指挥控制系统研究领域最基本的问题之一。针对复杂的网络化环境,拓扑统计模型对于构建可用、可信、可控的网络化指挥控制系统拓扑具有重要意义。对网络化指挥控制系统的功能性、安全性和服务质量方面的拓扑统计特性需求进行了总结,然后分别对当前的代表性拓扑模型进行分析,指出这些模型相对于网络化指挥控制系统拓扑统计特性需求存在的不足,最后给出研究中面临的问题和需要研究的内容,为该领域的下一步研究提供参考。     

一种新的高脉冲重复频率雷达多假设跟踪方法

高脉冲重复频率雷达目标跟踪时面临解距离模糊问题。现有方法需要在每个驻留时间内至少2帧检测到目标才能解距离模糊,新近提出的多假设方法虽然可以克服这一不足,但当模糊区间发生变化时会出现解距离模糊错误的情况。针对该问题,提出一种新的多假设方法,基于统计距离最小原则获取正确假设区间以实现目标跟踪,从而克服了现有多假设方法的不足。仿真表明该方法的收敛速度和跟踪精度均优于现有多假设方法。     

基于OWA算子的军队院校物资采购招投标管理研究

针对军队院校物资采购招投标管理问题,文中分析了军队院校物资采购招投标的特点,研究了基于合同的谈判机制;针对评标过程中,其所评指标中存在定量指标和定性指标的特点,提出一种基于OWA算子和语言OWA算子的综合多属性群决策方法,实现了招投标管理中的评标、定标。最后,通过实例说明了该方法的有效性及合理性。     

A produce‐to‐stock system with advance demand information and secondary customers

We consider a manufacturer (i.e., a capacitated supplier) that produces to stock and has two classes of customers. The primary customer places orders at regular intervals of time for a random quantity, while the secondary customers request a single item at random times. At a predetermined time the manufacturer receives advance demand information regarding the order size of the primary customer. If the manufacturer is not able to fill the primary customer's demand, there is a penalty. On the other hand, serving the secondary customers results in additional profit; however, the manufacturer can refuse to serve the secondary customers in order to reserve inventory for the primary customer. We characterize the manufacturer's optimal production and stock reservation policies that maximize the manufacturer's discounted profit and the average profit per unit time. We show that these policies are threshold‐type policies, and these thresholds are monotone with respect to the primary customer's order size. Using a numerical study we provide insights into how the value of information is affected by the relative demand size of the primary and secondary customers. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2007