Higher‐order Markov chain models for categorical data sequences*

In this paper we study higher‐order Markov chain models for analyzing categorical data sequences. We propose an efficient estimation method for the model parameters. Data sequences such as DNA and sales demand are used to illustrate the predicting power of our proposed models. In particular, we apply the developed higher‐order Markov chain model to the server logs data. The objective here is to model the users' behavior in accessing information and to predict their behavior in the future. Our tests are based on a realistic web log and our model shows an improvement in prediction. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

抢险救灾非战争军事行动中应急资源调度网络的优化方法

抢险救灾非战争军事行动包括道路抢修和物资运输等任务,而这两类任务在灾后应急资源调度中存在关联性的影响,且面临路网结构可变及需求随机模糊等挑战,对此,提出了一种非确定性应急资源调度网络双层规划模型,设计了基于蒙特卡洛方法与遗传算法耦合的智能启发式求解策略.通过对典型情境下应急资源调度案例进行分析建模和数值求解,说明了该模型和算法的合理性和有效性.     

On the optimality of the bayes prediction policy in two-echelon multistation inventory models

The present paper provides a proof that the Bayes prediction ordering policy developed in [3] is an optimal policy, in the sense that it minimizes the total expected discounted cost of ordering for any finite planning horizon.     

Transportation problems with some xij negative and transshipment problems

The general solution process of the Hitchcock transportation problem resulting from the application of the method of reduced matrices may give solutions with some negative x_ij values. This paper is devoted to a review of the reduced matrices method, an examination of suitable interpretation of sets of x_ij which include some negative values, and ways of interpreting these values in useful modifications of the Hitchcock problem. Such modifications include a) the reshipment problem, b) the overshipment problem, and c) the transshipment problem. Techniques are developed for determining and eliminating c_ij which are not optimal. These techniques and results are useful in solving the problems indicated above. The natural applicability of the simple and general method of reduced matrices is emphasized.     

Geometry and resolution of duality gaps

In this study we interpret the exterior penalty function method as a generalized lagrangian metliod which fills duality gaps in nonconvex problems. Geometry and resolution of these gaps from a duality point of view are highlighted.     

An economic model for planning strategic mobility posture

This paper describes a linear programming model used to perform cost-effectiveness analysis to determine the requirements for military strategic mobility resources. Expenditures for three classes of economic alternatives are considered: purchase of transportation resources; prepositioning of material; and augmentation of port facilities. The mix of economic alternatives that maximizes the effectiveness of the resultant transportation system is determined for a given investment level. By repeating the analysis for several levels of investment, a cost-effectiveness tradeoff curve can be developed.     

The resource constrained project scheduling problem with multiple crashable modes: An exact solution method

We introduce a formulation and an exact solution method for a nonpreemptive resource constrained project scheduling problem in which the duration/cost of an activity is determined by the mode selection and the duration reduction (crashing) within the mode. This problem is a natural combination of the time/cost tradeoff problem and the resource constrained project scheduling problem. It involves the determination, for each activity, of its resource requirements, the extent of crashing, and its start time so that the total project cost is minimized. We present a branch and bound procedure and report computational results with a set of 160 problems. Computational results demonstrate the effectiveness of our procedure. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 107–127, 2001     

Note: Optimal allocation of resources to nodes of series systems with respect to failure-rate ordering

Allocation of spare components in a system in order to optimize the lifetime of the system with respect to a suitable criterion is of considerable interest in reliability, engineering, industry, and defense. We consider the problem of allocation of K active spares to a series system of independent and identical components in order to optimize the failure-rate function of the system. © 1997 John Wiley & Sons, Inc.     

反导作战指控系统信息流时延模型研究与应用

在现代反导作战中,如何规划反导作战指控系统从而缩短目标、指挥信息传输时间和提高指挥精度是很重要的问题。基于此展开讨论,首先设计规划了3种反导作战指控系统信息流时延模型并提出了应用原则,其次分别以一典型3 500 km TBM和不同射程TBM为例进行了时延模型仿真计算和分析,最后通过分析计算结果给出反导作战指控系统建设性结论。     

基于不同模式的反导作战管理与敏感性分析

针对反导作战指控系统作战管理任务与过程,分别构建了层次式、中心式和分布式3种作战管理模式。基于3种管理模式,采用以仿真系统搭建作战环境进行对抗的仿真评估方法,以拦截比率（发射数/拦截数）为评估参数对不同作战管理模式的效能进行了仿真评估,同时对影响评估效能的参数进行了敏感性分析。根据分析评估结果,明确了在不同作战样式下采用不同作战管理模式的基本原则。