Analysis of algorithms for two‐stage flowshops with multi‐processor task flexibility

In this article we introduce a 2‐machine flowshop with processing flexibility. Two processing modes are available for each task: namely, processing by the designated processor, and processing simultaneously by both processors. The objective studied is makespan minimization. This production environment is encountered in repetitive manufacturing shops equipped with processors that have the flexibility to execute orders either individually or in coordination. In the latter case, the product designer exploits processing synergies between two processors so as to execute a particular task much faster than a dedicated processor. This type of flowshop environment is also encountered in labor‐intensive assembly lines where products moving downstream can be processed either in the designated assembly stations or by pulling together the work teams of adjacent stations. This scheduling problem requires determining the mode of operation of each task, and the subsequent scheduling that preserves the flowshop constraints. We show that the problem is ordinary NP‐complete and obtain an optimal solution using a dynamic programming algorithm with considerable computational requirements for medium and large problems. Then, we present a number of dynamic programming relaxations and analyze their worst‐case error performance. Finally, we present a polynomial time heuristic with worst‐case error performance comparable to that of the dynamic programming relaxations. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

Waypoint analysis for command and control

Command and Control (C2) in a military setting can be epitomized in battles‐of‐old when commanders would seek high ground to gain superior spatial‐temporal information; from this vantage point, decisions were made and relayed to units in the field. Although the fundamentals remain, technology has changed the practice of C2; for example, enemy units may be observed remotely, with instruments of varying positional accuracy. A basic problem in C2 is the ability to track an enemy object in the battlespace and to forecast its future position; the (extended) Kalman filter provides a straightforward solution. The problem changes fundamentally if one assumes that the moving object is headed for an (unknown) location, or waypoint. This article is concerned with the new problem of estimation of such a waypoint, for which we use Bayesian statistical prediction. The computational burden is greater than an ad hoc regression‐based estimate, which we also develop, but the Bayesian approach has a big advantage in that it yields both a predictor and a measure of its variability. © 2004 Wiley Periodicals, Inc. Naval Research Logistics, 2004     

一种基于三角面元的目标RCS实用计算方法

提出一种计算复杂目标高频区RCS的实用方法。首先采用3DStudioMax对装甲车进行三角面元模拟,然后运用路德维格积分[1]和物理绕射理论(PTD)计算目标的雷达散射截面积,通过对方柱RCS的计算,验证了所提方法的有效性,最后给出了C波段和X波段不同极化的装甲车和坦克RCS的方位分布图。     

中庭内步梯在火灾疏散中的应用探讨

对中庭内步梯在火灾情况下人员紧急疏散的使用进行了探讨,提出了使用水幕减弱火灾辐射危害的措施,并运用火灾危险分析方法进行了论述。     

无人机载多传感器集成与数据融合

介绍了无人机在情报、监视和侦察(ISR)领域的作用,分析研究了无人机(UAV)载传感器的种类、特点、集成特性及组合使用方式,说明了无人机载多传感器集成与数据融合的优点、功能组成.针对无人机载传感器的特点分析了多传感器组合、体系结构和特点,介绍了其主要算法,提出了发展趋势.     

针对国家导弹防御系统突防措施研究

美国为了追求绝对的安全,不顾国际社会的反对,贸然发展其国家弹道导弹防御系统。为了追求世界的制衡,必须研究如何突破弹道导弹防御系统。简述了NMD的发展演变,在分析了美国的国家导弹防御系统构成的基础上,针对其使用的拦截手段,重点分析了弹道导弹突破NMD的7种可能措施。     

防空旅(团)战斗保障体系效能评估模型

防空旅(团)战斗保障体系的效能是形成良好防空作战能力的关键因素之一,结合防空旅(团)的实际情况,建立了防空旅(团)战斗保障体系的效能指标体系,应用AHP法(层次分析法)确立了各因素的权重,给定了防空旅(团)战斗保障体系效能的评价指标,采用模糊综合评判,建立了二级的评估模型,实现了对防空旅(团)战斗保障体系效能的量化评判模型,并通过实例分析证明了该方法的可行性。     

仿真网格的初步实践

描述了仿真网格的技术内涵、体系结构和功能,以及实现过程中的关键技术等,并以美国的SF Express项目为例介绍了网格技术如何在功能和性能上发展分布式仿真技术。最后,介绍了所参与完成的一个仿真网格实验系统,包括其工作目标、应用模式和解决的关键技术等。     

一种可实现TF/TA2的无人飞行器三维航迹规划方法

从规划空间的有效表达着手对无人飞行器三维航迹规划展开研究,基于地形和威胁提出的飞行器航迹规划方法将航迹规划分为学习阶段和查询阶段,环境信息和飞行器的大部分约束条件结合在路线图的构造过程中,航迹搜索在此路线图中进行并最终实现全部约束条件.试验结果显示,该方法可以实时获得实现TF/TA2的三维航迹.     

气体炮法测评抗冲元件的动态特性

提出了一种测评抗冲元件动态特性的方法.通过气体炮发射的炮弹撞击砧块,使之获得一定的初速度,再利用砧块的惯性对抗冲元件施加冲击载荷.使用激光位移传感器和测力钢块分别测量力和位移,解决了特殊情况下数据测量的问题.