动态规划在消防增援调度中的应用

由于各消防中队一般规模较小,对于较大规模的火灾需要多个消防队共同救护,此时若能够实现增援调度的最优化可以提高这些同时出现的火灾被全部扑灭的概率。利用多阶段动态规划对增援调度进行了研究,并分析了具体案例。通过分析得出此方法有助于改善消防资源分配状况,以实现最大程度地减小经济损失。     

联合作战的远程火力战法动态分析方法*

用定量动态分析方法开发远程火力战法是联合作战规划中必须解决的重要问题。借助仿真和博弈分析的混合方法,在对博弈效用函数计算的基础上,构建基于识别真目标、假目标以及火力命中目标概率的二人非零和(TPNZS)非合作博弈模型来开发远程火力战法动态分析方法,对两个典型的联合作战远程火力打击战法性能的初步动态分析表明:战场势态的动态变化直接影响定量规划最优战法的结果。     

Dynamic routing of prioritized warranty repairs

Recent years have seen a strong trend toward outsourcing warranty repair services to outside vendors. In this article we consider the problem of dynamically routing warranty repairs to service vendors when warranties have priority levels. Each time an item under warranty fails, it is sent to one of the vendors for repair. Items covered by higher priority warranty receive higher priority in repair service. The manufacturer pays a fixed fee per repair and incurs a linear holding cost while an item is undergoing or waiting for repair. The objective is to minimize the manufacturer's long‐run average cost. Because of the complexity of the problem, it is very unlikely that there exist tractable ways to find the optimal routing strategies. Therefore, we propose five heuristic routing procedures that are applicable to real‐life problems. We evaluate the heuristics using simulation. The simulation results show that the index‐based “generalized join the shortest queue” policy, which applies a single policy improvement step to an initial state‐independent policy, performs the best among all five heuristics. © 2007 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

石英晶体测试实验中干扰的消除

Ｙ－切石英晶体的各向异性物理特性,使它在正碰撞或平面冲击波作用条件下能产生压剪波的传播,为实现对材料的压剪加载实验研究提供了条件。由于石英晶体的压电效应,国外采用了ＶＩＳＡＲ技术进行测试。在我们的工作中,首次尝试用锰铜压阻法和电磁质速测量法进行测试。压电效应造成了明显的干扰,妨碍信号的获取。实验中用磁控溅射方法将石英晶体表面镀银层约１μｍ,达到了中和极化电荷、屏蔽极化电场的目的,比较成功地消除了压电干扰,获得了有效的测试信号。     

Approximate dynamic programming methods for an inventory allocation problem under uncertainty

We propose two approximate dynamic programming methods to optimize the distribution operations of a company manufacturing a certain product at multiple production plants and shipping it to different customer locations for sale. We begin by formulating the problem as a dynamic program. Our first approximate dynamic programming method uses a linear approximation of the value function and computes the parameters of this approximation by using the linear programming representation of the dynamic program. Our second method relaxes the constraints that link the decisions for different production plants. Consequently, the dynamic program decomposes by the production plants. Computational experiments show that the proposed methods are computationally attractive, and in particular, the second method performs significantly better than standard benchmarks. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

Optimal pricing and inventory control policy in periodic‐review systems with fixed ordering cost and lost sales

This paper studies a periodic‐review pricing and inventory control problem for a retailer, which faces stochastic price‐sensitive demand, under quite general modeling assumptions. Any unsatisfied demand is lost, and any leftover inventory at the end of the finite selling horizon has a salvage value. The cost component for the retailer includes holding, shortage, and both variable and fixed ordering costs. The retailer's objective is to maximize its discounted expected profit over the selling horizon by dynamically deciding on the optimal pricing and replenishment policy for each period. We show that, under a mild assumption on the additive demand function, at the beginning of each period an (s,S) policy is optimal for replenishment, and the value of the optimal price depends on the inventory level after the replenishment decision has been done. Our numerical study also suggests that for a sufficiently long selling horizon, the optimal policy is almost stationary. Furthermore, the fixed ordering cost (K) plays a significant role in our modeling framework. Specifically, any increase in K results in lower s and higher S. On the other hand, the profit impact of dynamically changing the retail price, contrasted with a single fixed price throughout the selling horizon, also increases with K. We demonstrate that using the optimal policy values from a model with backordering of unmet demands as approximations in our model might result in significant profit penalty. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

A multilevel passenger screening problem for aviation security

Passenger prescreening is a critical component of aviation security systems. This paper introduces the Multilevel Allocation Problem (MAP), which models the screening of passengers and baggage in a multilevel aviation security system. A passenger is screened by one of several classes, each of which corresponds to a set of procedures using security screening devices, where passengers are differentiated by their perceived risk levels. Each class is defined in terms of its fixed cost (the overhead costs), its marginal cost (the additional cost to screen a passenger), and its security level. The objective of MAP is to assign each passenger to a class such that the total security is maximized subject to passenger assignments and budget constraints. This paper shows that MAP is NP‐hard and introduces a Greedy heuristic that obtains approximate solutions to MAP that use no more than two classes. Examples are constructed using data extracted from the Official Airline Guide. Analysis of the examples suggests that fewer security classes for passenger screening may be more effective and that using passenger risk information can lead to more effective security screening strategies. © 2006 Wiley Periodicals, Inc. Naval Research Logistics, 2006     

动态教学法在《政治学原理》课程教学中的运用

政治学原理课程在授课过程中存在着教材内容的确定性和稳定性,而无论从国际国内形势还是从政治学研究而言,政治学所关注的范围和内容又都处于动态的不断发展变化的。笔者以为,只有在授课中具体运用动态教学法,通过联系学生自身、联系社会现实、联系国家大事、联系国际政治等实际,才能使政治学原理课程在马克思主义基本原则的指导下,更富有时代特征和生活气息,使学生真正学有所获。     

基于矩量法对分段指数电阻加载Koch分形天线阻抗特性研究

提出一种新的分段指数电阻加载Koch分形偶极天线,其加载电阻沿天线从馈电点按指数规律递增.基于矩量法(MOM)分析计算其阻抗特性,结果表明,该天线能满足现代通信系统对天线小型宽带的要求,也为分析设计小型宽带天线提供了一种有效的方法与思路.     

聚氨酯阻尼材料的结构设计及其动态力学性能的研究

据聚合物阻尼性能定量化理论,设计合成了软段结构、分子量不同以及含支链的聚氨酯.动态力学性能测试表明,含聚环氧丙烷二醇(PPG,Mn=2 000)、聚己二酸二乙二醇(PDEA,Mn=2 000)、聚己二酸乙二醇(PEAG,Mn=2 000)软段的试样的温域宽和内耗峰高.当软段分子量增加时,材料的损耗因子增加.组份相同时,含支链比不含支链的聚氨酯试样的内耗峰高,阻尼值大.