Optimal material control in an assembly system with component commonality

Allocation of scarce common components to finished product orders is central to the performance of assembly systems. Analysis of these systems is complex, however, when the product master schedule is subject to uncertainty. In this paper, we analyze the cost—service performance of a component inventory system with correlated finished product demands, where component allocation is based on a fair shares method. Such issuing policies are used commonly in practice. We quantify the impact of component stocking policies on finished product delays due to component shortages and on product order completion rates. These results are used to determine optimal base stock levels for components, subject to constraints on finished product service (order completion rates). Our methodology can help managers of assembly systems to (1) understand the impact of their inventory management decisions on customer service, (2) achieve cost reductions by optimizing their inventory investments, and (3) evaluate supplier performance and negotiate contracts by quantifying the effect of delivery lead times on costs and customer service. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:409–429, 2001     

Waiting time analysis for a queueing system with time‐limited service and exponential timer

We consider a single‐queue with exhaustive or gated time‐limited services and server vacations, in which the length of each service period at the queue is controlled by a timer, i.e., the server serves customers until the timer expires or the queue becomes empty, whichever occurs first, and then takes vacations. The customer whose service is interrupted due to the timer expiration may be attended according to nonpreemptive or preemptive service disciplines. For the M/G/1 exhaustive/gated time‐limited service queueing system with an exponential timer and four typical preemptive/nonpreemptive service disciplines, we derive the Laplace—Stieltjes transforms and the moment formulas for waiting times and sojourn times through a unified approach, and provide some new results for these time‐limited service disciplines. © John Wiley & Sons, Inc. Naval Research Logistics 48: 638–651, 2001.     

Generating Pareto‐optimal boundary points in multiparty negotiations using constraint proposal method

In this paper a constraint proposal method is developed for computing Pareto‐optimal solutions in multiparty negotiations over continuous issues. Constraint proposal methods have been previously studied in a case where the decision set is unconstrained. Here we extend the method to situations with a constrained decision set. In the method the computation of the Pareto‐optimal solutions is decentralized so that the DMs do not have to know each others' value functions. During the procedure they have to indicate their optimal solutions on different sets of linear constraints. When the optimal solutions coincide, the common optimum is a candidate for a Pareto‐optimal point. The constraint proposal method can be used to generate either one Pareto‐optimal solution dominating the status quo solution or several Pareto‐optimal solutions. In latter case a distributive negotiation among the efficient points can be carried out afterwards. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 210–225, 2001     

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     

舰船维修器材保障点选址决策模型及算法

传统的最大覆盖选址模型没有考虑对服务半径外的需求点的满足和服务时间的响应,而在舰船维修器材保障中,不论需求点到保障点的距离是否大于服务半径,都应对其进行保障服务,且在保障过程中要满足保障时间控制在不影响舰船正常维修任务时间内。针对此问题,运用广义最大覆盖选址模型和时间满意度函数,构建基于时间满意的广义最大覆盖选址模型,并运用一种混合算法———基于遗传模拟退火算法的BP算法对模型进行求解。最后,运用该算法对实例进行了分析计算,计算结果验证了该算法的有效性。     

基于AHP算法的精确作战目标价值排序问题研究

针对精确作战中的目标价值排序问题,从战场实际出发建立了目标价值体系,并在此基础上应用AHP原理提出了目标价值排序的递阶层次结构模型．通过成对比较实现作战目标价值的精确排序,为指挥员基于目标价值的决策提供理论依据．     

Are non‐lethal weapons a viable military option to strengthen the hearts and minds approach in Afghanistan?

Commanders of the International Security Assistance Force (ISAF) have repeatedly stressed the hearts and minds approach in Afghanistan, in saying that the human terrain is decisive for a successful outcome of the mission. Avoidance of civilian casualties is considered of strategic importance, and by nature highly dependent on the management of tactical level Escalation of Force (EoF) situations. Non‐lethal weapons (NLWs) are expected to enable tactical commanders to avoid innocent civilian casualties in such situations. This article considers a selected NLW on its potential to accomplish this requirement. It uses a defence technology assessment approach to analyse EoF situations experienced by Dutch ISAF forces in which the NLW is inserted. The analysis demonstrates that a range of contextual factors in the Afghanistan high‐risk environment tend to narrow down the window of opportunity for the NLW to help defuse the risk of unintended civil casualties.     

A spatial rank‐based multivariate EWMA control chart

Nonparametric control charts are useful in statistical process control when there is a lack of or limited knowledge about the underlying process distribution, especially when the process measurement is multivariate. This article develops a new multivariate self‐starting methodology for monitoring location parameters. It is based on adapting the multivariate spatial rank to on‐line sequential monitoring. The weighted version of the rank‐based test is used to formulate the charting statistic by incorporating the exponentially weighted moving average control scheme. It is robust to non‐normally distributed data, easy to construct, fast to compute and also very efficient in detecting multivariate process shifts, especially small or moderate shifts which occur when the process distribution is heavy‐tailed or skewed. As it avoids the need for a lengthy data‐gathering step before charting and it does not require knowledge of the underlying distribution, the proposed control chart is particularly useful in start‐up or short‐run situations. A real‐data example from white wine production processes shows that it performs quite well. © 2012 Wiley Periodicals, Inc. Naval Research Logistics 59: 91–110, 2012     

Optimal pricing for a short life‐cycle product when customer price‐sensitivity varies over time

Technology products often experience a life‐cycle demand pattern that resembles a diffusion process, with weak demand in the beginning and the end of the life cycle and high demand intensity in between. The customer price‐sensitivity also changes over the life cycle of the product. We study the prespecified pricing decision for a product that exhibits such demand characteristics. In particular, we determine the optimal set of discrete prices and the times to switch from one price to another, when a limited number of price changes are allowed. Our study shows that the optimal prices and switching times show interesting patterns that depend on the product's demand pattern and the change in the customers' price sensitivity over the life cycle of the product. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

基于改进人工鱼群算法的WNN优化设计

针对人工鱼群算法优化设计小波神经网络(WNN)的缺陷,引入了视野范围与步长的自调整策略,以提高搜索效率和收敛速度。改进后的人工鱼群算法可在WNN的搜索空间中同时确定参数初始值和隐节点数。仿真实例验证了其有效性。