On a new approach to the analysis of stationary inventory problems

The intent of this paper is to demonstrate that the theory of stationary point processes is a useful tool for the analysis of stationary inventory systems. In conventional inventory theory, the equilibrium distributions for a specified inventory policy are obtained, whenever possible, by recursive or limiting procedures, or both. A different and more direct approach, based on stationary point processes, is proposed here. The time instants at which stock delivery is effected are viewed as points of the stationary point process, which possesses uniform statistical properties on the entire real axis; hence the equilibrium statistics of the inventory process can be calculated directly. In order to best illustrate this approach, various examples are given, including some that constitute new results.     

Scheduling with variable time slot costs

In this article, we study a class of new scheduling models where time slot costs have to be taken into consideration. In such models, processing a job will incur certain cost which is determined by the time slots occupied by the job in a schedule. The models apply when operational costs vary over time. The objective of the scheduling models is to minimize the total time slot costs plus a traditional scheduling performance measure. We consider the following performance measures: total completion time, maximum lateness/tardiness, total weighted number of tardy jobs, and total tardiness. We prove the intractability of the models under general parameters and provide polynomial‐time algorithms for special cases with non‐increasing time slot costs.© 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

舰载制导炮弹作战效能仿真分析

选择毁伤概率作为效能指标,在分析使用舰裁制导炮弹时岸作战射击误差的基础上建立了毁伤概率模型,并应用蒙特卡洛法对模型进行了仿真计算,同时研究分析了各项技术指标参数对毁伤概率的影响.仿真结果表明,射弹散布概率误差对毁伤概率的影响程度与其它因素相比较轻,射击诸元误差对制式弹对岸打击毁伤概率的影响明显大于制导炮弹,并且得到了激光照射距离和各种误差参数的理想分布,分析的结果可为舰栽制导炮弹的使用和技术指标优化提供一定的参考依据.     

A nonparametric Bayes approach to decide system burn-in time

Burn-in is the preconditioning of assemblies and the accelerated power-on tests performed on equipment subject to temperature, vibration, voltage, radiation, load, corrosion, and humidity. Burn-in techniques are widely applied to integrated circuits (IC) to enhance the component and system reliability. However, reliability prediction by burn-in at the component level, such as the one using the military (e.g., MIL-STD-280A, 756B, 217E [23–25]) and the industrial standards (e.g., the JEDEC standards), is usually not consistent with the field observations. Here, we propose system burn-in, which can remove many of the residual defects left from component and subsystem burn-in (Chien and Kuo [6]). A nonparametric model is considered because 1) the system configuration is usually very complicated, 2) the components in the system have different failure mechanisms, and 3) there is no good model for modeling incompatibility among components and subsystems (Chien and Kuo [5]; Kuo [16]). Since the cost of testing a system is high and, thus, only small samples are available, a Bayesian nonparametric approach is proposed to determine the system burn-in time. A case study using the proposed approach on MCM ASIC's shows that our model can be applied in the cases where 1) the tests and the samples are expensive, and 2) the records of previous generation of the products can provide information on the failure rate of the system under investigation. © 1997 John Wiley & Sons, Inc. Naval Research Logistics 44: 655–671, 1997     

防空作战战场态势的定量化分析模型

在防空作战中,战场态势的分析非常重要,它是辅助决策的基础。针对战场态势的问题,以集对分析的同异反联系度为基础,构造了战场态势的分析模型,进行了深入探讨。最后,通过实例计算表明了分析模型对于评估战场态势的可行性和有效性。     

Modeling lead-time demand for lumpy demand and variable lead time

Slow-moving items that occasionally exhibit large demand transactions are known as lumpy demand items. In modeling lumpy demand patterns, it is often assumed that the arrival of customer orders follows a Poisson process and that the order sizes are given by the geometric distribution. This gives rise to a stuttering Poisson (sP) model of lumpy demand. If lead times are constant, the result is a stuttering Poisson model of lead-time demand. Heretofore, authors such as Ward [18] and Mitchell, Rappold, and Faulkner [12] have assumed constant lead times and thus stopped at the sP model. We develop this model further by introducing the effect of lead-time variability. For illustration, we use the normal and the gamma distributions as characterizations of lead time. The resulting models of lead-time demand are referred to as the geometric Poisson normal (GPN) and the geometric Poisson gamma (GPG). For both these models, the article derives tractable expressions for calculating probabilities. Errors introduced by using the sP, constant lead-time model instead of the exact, variable lead-time model are also illustrated.     

On the first time a separately maintained parallel system has been down for a fixed time

Consider a system consisting of n separately maintained independent components where the components alternate between intervals in which they are “up” and in which they are “down”. When the i^th component goes up [down] then, independent of the past, it remains up [down] for a random length of time, having distribution F_i[G_i], and then goes down [up]. We say that component i is failed at time t if it has been “down” at all time points s ?[t-A.t]: otherwise it is said to be working. Thus, a component is failed if it is down and has been down for the previous A time units. Assuming that all components initially start “up,” let T denote the first time they are all failed, at which point we say the system is failed. We obtain the moment-generating function of T when n = l, for general F and G, thus generalizing previous results which assumed that at least one of these distributions be exponential. In addition, we present a condition under which T is an NBU (new better than used) random variable. Finally we assume that all the up and down distributions F_i and G_i i = l,….n, are exponential, and we obtain an exact expression for E(T) for general n; in addition we obtain bounds for all higher moments of T by showing that T is NBU.     

A many-on-many stochastic duel model for a mountain battle

Terrain plays a major role in mountain battle. The advancing (attacking) force is usually restricted to move in a single column—along a narrow, winding, and steep road. The defending force, on the other hand, which is static, can select its positions such that most of its firepower can be effective against the front unit(s) of the attacking force. This combat situation is modeled as a special type of the many-on-many stochastic duel. This duel is a series of many-on-one subduels where at each such subduel the defending force units simultaneously engage the single exposed front unit of the attacking force. This special type of many-on-many stochastic duel demonstrates the possibility of practical applications of stochastic duel theory.     

On queueing systems with variable service capacities

In some queueing systems the total service capacity utilized at any given time is a variable under the control of a decision maker. Management doctrines are examined which prescribe the actual service capacity as a function of the queue length and the recent history of the system. Steady state probabilities, expected queue lengths and frequencies of change in capacity are evaluated for a wide class of possible control schemes. Optimization procedures are outlined.     

A continuous-review inventory system with lost sales and variable lead time

Using a system-point (SP) method of level crossings, we derive the stationary distribution of the inventory level (stock on hand) in a continuous-review inventory system with compound Poisson demand, Erlang as well as hyperexponentially distributed lead times, and lost sales. This distribution is then used to formulate long-run average cost functions with/without a service level constraint. Some numerical results are also presented, and compared with the Hadley and Whitin heuristic. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 259–278, 1998     

基于遗传算法的潜射反舰导弹综合作战效能分析

提出了直接根据单指标相对隶属度的模糊评价矩阵,构造层次分析法中的判断矩阵用以确定各评价指标权重的方法,给出了用遗传算法检验和修正判断矩阵的一致性和计算判断矩阵各要素的权重的模糊综合评价模型,对潜射反舰导弹作战效能进行了综合评估和排序.实例表明,该方法简便通用,计算结果较为客观和稳定.     

中国崛起的“时态”论析

西方舆论夸大了“中国崛起”的事实,中国人对此必须有清醒的认识。“中国崛起”应当准确地理解为“中国现在正在崛起”。因为中国目前离崛起的目标存在巨大经济差距和综合国力差距,目前只是处在崛起的起点上,具备了崛起的基础和条件。     

增强科技素养，提高打赢能力

增强高级指挥员的科技认知力、创新力、运用力是科技强军的必然要求。本文从战争演变、融合发展、应对威胁切入,对高级指挥员如何提升科技认知力层次、增强科技创新力效能、提高科技运用力水平谈了几点初步思考。     

基于语言评价信息的多方案选优研究

通过LWD和LOWA算子,给出了一种算法。该算法在预先定义语言短语排序的情况下,可将专家群给出的多个指标下多个方案的语言评价信息集结为对方案的语言短语排序,从而可选出最优方案,并通过仿真算例,证明了该方法的有效性。     

新型装备作战指挥信息系统军事需求论证的反向分析方法

基于新型装备作战指挥信息系统构成及功能,提出了"体系作战效果-作战运用方式-关键能力需求-需求方案决策优化"的军事需求映射机制,构建了新型装备作战指挥信息系统军事需求论证的反向分析总体框架,并分析反向分析方法的内容和设计了流程。该研究对新型作战力量指挥信息系统的顶层设计和工程建设具有一定的价值,对于开展其他复杂系统的体系结构研究也具有借鉴意义。     

基于信息系统的作战试验指挥控制技术及发展分析

装备作战试验成为现代装备应用能力和作战效能考核的重要模式,基于信息系统的指挥控制作为装备作战试验全过程的黏合剂,发挥着控制试验效益、试验进程和试验安全等重要作用。本文以美军的指挥控制技术为背景,论述了作战试验的相关概念,分析了信息化条件对指挥控制的影响,研究了信息化作战指挥控制结构模型和流程,最后提出了基于信息系统的作战试验发展趋势。     

Availability of an operating system during a given time interval: A dynamic programming approach

We consider the problem of running a one-unit failure system such that the probability that the system is operating over an entire prespecified time interval (or at least at some time instant during the interval) is maximized. A fixed number of unused units having identically distributed random operating times are at the controller's disposal. Simple assumptions are made on the stochastic failure mechanism. In particular, the time required to activate a unit for the system is supposed to be constant. Analyzing the associated dynamic programming equations yields closed-form solutions. © 1996 John Wiley & Sons, Inc.     

An approach to postoptimality and sensitivity analysis of zero-one goal programs

In this article we present a methodology for postoptimality and sensitivity analysis of zero-one goal programs based on the set of k-best solutions. A method for generating the set of k-best solutions using a branch and bound algorithm and an implicit enumeration scheme for multiple objective problem are discussed. Rules for determining the range of parameter changes that still allows a member of the k-best set to be optimal are developed. An investigation of a sufficient condition for postoptimality analysis is also presented.     

舰空导弹武器系统作战软件试验测试平台

由舰空导弹武器系统在试验中出现的作战软件故障,提出了加强软件可靠性评估的观点和建立舰空导弹武器系统作战软件试验测试平台的构想。给出了基于海上试验环境的作战软件试验测试平台的方案、试验方案设计、试验实施策略以及可靠性评估方法。