战时弹药供应协同调运模型研究

弹药协同调运是战时弹药保障工作中的重要环节,其协同调运的合理性将直接影响到弹药保障工作的顺利进行.针对弹药的调运问题,从战时技术实施与应用角度研究弹药的调运问题,以到达需求点的运输时间、弹药输送车数量以及弹药损失量为优化目标,建立一种多目标决策模型,为缩短运输时间、减少弹药输送车数量、提高安全到达需求点的弹药量提供一种实用的方法.     

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     

兵力需求系统动力学模型研究

针对兵力需求的动态不确定问题,定性分析兵力需求的影响因素及其相互关系,运用Vensim软件构建兵力需求系统动力学模型,定量研究兵力需求相关变量间因果关系及需求变化的动态规律,并进行数值仿真.结果表明,系统动力学用于兵力需求的研究,有效地解决了系统某些参数关系难以量化、数据不足等问题.     

Quantity discount pricing policies for heterogeneous retailers with price sensitive demand

Although quantity discount policies have been extensively analyzed, they are not well understood when there are many different buyers. This is especially the case when buyers face price‐sensitive demand. In this paper we study a supplier's optimal quantity discount policy for a group of independent and heterogeneous retailers, when each retailer faces a demand that is a decreasing function of its retail price. The problem is analyzed as a Stackelberg game whereby the supplier acts as the leader and buyers act as followers. We show that a common quantity discount policy that is designed according to buyers' individual cost and demand structures and their rational economic behavior is able to significantly stimulate demand, improve channel efficiency, and substantially increase profits for both the supplier and buyers. Furthermore, we show that the selection of all‐units or incremental quantity discount policies has no effect on the benefits that can be obtained from quantity discounts. © 2005 Wiley Periodicals, Inc. Naval Research Logistics, 2005     

舰艇编队海上运输补给物资需求预测方法

按照是否与任务、事件相关,将物资需求分为两类,对于任务、事件相关物资需求的预测,将任务进行合理的分解,并根据物资消耗与任务、事件之间的关系,给出了预测的一般模型;对于与任务、事件联系不紧密的物资需求的预测,则根据历史经验及该物资固有的消耗规律,提出了经验预测模型。为了解决舰艇编队海上运输补给物资需求预测所存在的问题,利用案例推理的方法生成了预测所需的样本数据,以最小二乘向量机(LSSVM)模型为预测模型,并以岛屿进攻作战的防空弹药需求预测为例进行了实例分析。结果表明:案例推理生成的样本数据可用,选用LSSVM模型的预测结果与其他预测模型表现出了一致性,但LSSVM相对误差较小;该方法在某种程度上解决了样本数据有限的问题,适用于作战物资需求的预测问题。     

The (s,Q) inventory model with Erlang lead time and deterministic demand

We develop a simple, approximately optimal solution to a model with Erlang lead time and deterministic demand. The method is robust to misspecification of the lead time and has good accuracy. We compare our approximate solution to the optimal for the case where we have prior information on the lead‐time distribution, and another where we have no information, except for computer‐generated sample data. It turns out that our solution is as easy as the EOQ's, with an accuracy rate of 99.41% when prior information on the lead‐time distribution is available and 97.54–99.09% when only computer‐generated sample information is available. Apart from supplying the inventory practitioner with an easy heuristic, we gain insights into the efficacy of stochastic lead time models and how these could be used to find the cost and a near‐optimal policy for the general model, where both demand rate and lead time are stochastic. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

Newsvendor problems with sequentially revealed demand information

This article analyzes a capacity/inventory planning problem with a one‐time uncertain demand. There is a long procurement leadtime, but as some partial demand information is revealed, the firm is allowed to cancel some of the original capacity reservation at a certain fee or sell off some inventory at a lower price. The problem can be viewed as a generalization of the classic newsvendor problem and can be found in many applications. One key observation of the analysis is that the dynamic programming formulation of the problem is closely related to a recursion that arises in the study of a far more complex system, a series inventory system with stochastic demand over an infinite horizon. Using this equivalence, we characterize the optimal policy and assess the value of the additional demand information. We also extend the analysis to a richer model of information. Here, demand is driven by an underlying Markov process, representing economic conditions, weather, market competition, and other environmental factors. Interestingly, under this more general model, the connection to the series inventory system is different. © 2012 Wiley Periodicals, Inc. Naval Research Logistics 2012     

Optimal inventory control policy for periodic‐review inventory systems with inventory‐level‐dependent demand

We consider a setting in which inventory plays both promotional and service roles; that is, higher inventories not only improve service levels but also stimulate demand by serving as a promotional tool (e.g., as the result of advertising effect by the enhanced product visibility). Specifically, we study the periodic‐review inventory systems in which the demand in each period is uncertain but increases with the inventory level. We investigate the multiperiod model with normal and expediting orders in each period, that is, any shortage will be met through emergency replenishment. Such a model takes the lost sales model as a special case. For the cases without and with fixed order costs, the optimal inventory replenishment policy is shown to be of the base‐stock type and of the (s,S) type, respectively. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

基于作战任务的多机种故障备件需求模型

通过分析战时故障备件的需求特点,对备件的工作时间进行讨论,改进了传统的单机故障备件需求模型。根据多机种协同作战任务的不同,引入备件工作运行比的概念,在考虑飞机是否战损的前提下,建立了基于作战任务的多机种故障备件需求模型。算例分析证明了模型的有效性。