Dynamic coordination of production planning and sales admission control in the presence of a spot market

We consider the decision‐making problem of dynamically scheduling the production of a single make‐to stock (MTS) product in connection with the product's concurrent sales in a spot market and a long‐term supply channel. The spot market is run by a business to business (B2B) online exchange, whereas the long‐term channel is established by a structured contract. The product's price in the spot market is exogenous, evolves as a continuous time Markov chain, and affects demand, which arrives sequentially as a Markov‐modulated Poisson process (MMPP). The manufacturer is obliged to fulfill demand in the long‐term channel, but is able to rein in sales in the spot market. This is a significant strategic decision for a manufacturer in entering a favorable contract. The profitability of the contract must be evaluated by optimal performance. The current problem, therefore, arises as a prerequisite to exploring contracting strategies. We reveal that the optimal strategy of coordinating production and sales is structured by the spot price dependent on the base stock and sell‐down thresholds. Moreover, we can exploit the structural properties of the optimal strategy to conceive an efficient algorithm. © 2010 Wiley Periodicals, Inc. Naval Research Logistics, 2010     

Optimal control of a production‐inventory system with both backorders and lost sales

We consider the optimal control of a production inventory‐system with a single product and two customer classes where items are produced one unit at a time. Upon arrival, customer orders can be fulfilled from existing inventory, if there is any, backordered, or rejected. The two classes are differentiated by their backorder and lost sales costs. At each decision epoch, we must determine whether or not to produce an item and if so, whether to use this item to increase inventory or to reduce backlog. At each decision epoch, we must also determine whether or not to satisfy demand from a particular class (should one arise), backorder it, or reject it. In doing so, we must balance inventory holding costs against the costs of backordering and lost sales. We formulate the problem as a Markov decision process and use it to characterize the structure of the optimal policy. We show that the optimal policy can be described by three state‐dependent thresholds: a production base‐stock level and two order‐admission levels, one for each class. The production base‐stock level determines when production takes place and how to allocate items that are produced. This base‐stock level also determines when orders from the class with the lower shortage costs (Class 2) are backordered and not fulfilled from inventory. The order‐admission levels determine when orders should be rejected. We show that the threshold levels are monotonic (either nonincreasing or nondecreasing) in the backorder level of Class 2. We also characterize analytically the sensitivity of these thresholds to the various cost parameters. Using numerical results, we compare the performance of the optimal policy against several heuristics and show that those that do not allow for the possibility of both backordering and rejecting orders can perform poorly.© 2010 Wiley Periodicals, Inc. Naval Research Logistics 2010     

航母舰载机对空防御作战出航保障指挥决策建模

基于Agent的航母舰载机对空防御作战出航保障指挥决策系统,由数据部分和Agent组织部分组成.前者又含数据库、模型库、知识库、相关管理系统和MIS.后者包括五大决策Agent,通过界面Agent与用户进行交互,而与数据部分的交互则由DB监理Agent统一完成.对于系统内决策Agent的设计,可首先针对五大决策Agent的模板进行设计,再对其功能层进行实例化.     

改革开放以来我国经济法取得的主要成效及发展方向

中国特色经济法是改革开放的产物,有力地促进了社会主义市场经济的健康、快速发展。经济法在保证经济实现科学发展的同时,自身也突破了对调整能力的传统认识,区分了经济法与行政法,明确了经济法的正确定位,创新了经济法的发展观,提出了“经济法主体”概念,冲破了公法与私法的界限,形成了与相关学科协调发展的经济法学研究格局。今后,经济法的发展必须重视从完善社会主义市场经济基本制度,健全现代市场体系,规范政府科学干预经济生活,宏观调控的重点、热点、难点问题和基础理论研究的创新上把握研究重点,保证经济实现科学发展。     

高层建筑消防给水系统存在问题探讨

高层建筑高度高、结构复杂、火灾蔓延途径多、人员疏散困难,发生火灾后如控制不及时,后果不堪设想。因此,对高层建筑防火设计的要求越来越严格,而消防给水则是最重要的一个部分。对高层建筑消防给水系统形式、室内外消火栓、水泵接合器的设置等几个方面问题进行了研究,希望能为从事此方面工作的人员提供借鉴。     

指令时延对舰空导弹中末制导交班误差影响分析

从目标作直线飞行和机动飞行两种情况出发,建立相应的舰空导弹中末制导交班时的导引头指向误差模型和导弹速度矢量指向误差模型,指出了相应的误差修正方法,进行了仿真计算,并分析了计算结果.仿真结果验证了上述模型的正确性.     

复杂电磁环境下的电磁频谱管理效能评估研究

针对复杂电磁环境下的电磁频谱管理效能评估问题,提出一套系统地效能评估方法.首先对效能评估的指标体系进行了分析,然后提出了一种多模型混合的效能评估方法,最后对整个过程中效能评估的流程进行研究.通过实例仿真研究表明,该方法可以有效地对复杂电磁频谱下的电磁频谱管理效能进行评估.     

Iran’s Nuclear Fatwa: Analysis of a Debate

For more than a decade, Iran has been referring to a fatwa issued by its Supreme Leader, Ali Khamenei, proscribing nuclear weapons. The fatwa, however, not only failed to influence the process that led to the resolution of Iran’s nuclear crisis, but also has been met with a good deal of skepticism. The most commonly held suspicions about the credibility of the fatwa can be summed up in five central questions: (1) Has the nuclear fatwa actually been issued? (2) Does the fatwa apply to all the aspects of nuclear weapons including their production, possession and use? (3) What is the juridical status of the fatwa? (4) Was the nuclear fatwa issued only to deceive other nations? (5) Is the fatwa really irreversible? This article tries to answer these questions by providing a chronological review of the fatwa and analyzing all the relevant statements by Khamenei. The analysis is conducted against the background of Islamic principles, Shi’a jurisprudence and the history of the Islamic Republic of Iran. The article concludes that the fatwa is a credible religious decree and could indeed contribute to the cause of nuclear disarmament.     

接敌前基于D-S理论的空战意图预测

接敌前是指敌机刚进入我方预警系统的探测范围(一般为400 km),并截获敌机,获得了敌机的运动参数,对敌机进行实时跟踪。为了完成对敌机目标意图的预测,为接敌前的自主决策打下基础,在D-S证据理论的基础上,选取合适的态势元素,分析各态势元素对敌机意图的影响,建立了目标意图预测模型,该模型具有一定的表达性和准确性。仿真实验表明,使用该模型能在敌机相距较远时以一定的准确性判断敌机的意图,实用性强,为接敌前基于意图预测的自主决策留出足够的时间。     

VNS和SA相结合的指挥控制资源部署

针对指挥控制资源部署问题,引入任务复杂度来定义决策实体的工作负载,并建立以最小化决策实体工作负载的均方根为目标的优化模型。针对传统的层次聚类法容易陷入局部最优,提出了一种变邻域搜索(Variable Neighborhood Search,VNS)和模拟退火(Simulated Annealing,SA)相结合的具有全局性的求解方法,使用VNS进行全局寻优,使用SA对VNS中的邻域进行局部寻优。最后通过一个联合作战案例的平台调度方案,验证了所提方法的优越性。