Quasi-steady aerodynamic characteristics of Terminal Sensitive Bullets with short cylindrical portion

The aerodynamic characteristics are vital for short cylindrical Terminal Sensitive Bullets(TSB)with low aspect ratio,especially in terminal trajectory.Currently,there is little research in terms of the TSB and short cylinder with two free ends,and particularly in this trajectory,where the scanning angle β and roll angle α vary over a broad range between 0° and 180°.In this work,wind tunnel experiments are first conducted to learn the effects of Reynolds number and scanning angle on aerodynamic parameters for short cylinder with aspect ratio L/D = 1.Similar to infinite cylinder,for the short cylinder with two free ends,the drag crisis phenomenon still exists in the critical regime 1.7 × 105 ≤ Re ≤ 6.8 × 105.Then 3D simulations are performed to demonstrate the aerodynamic characteristics of short cylinder and TSB over a broad range of Re,L/D,α and β.The sensitivity analysis of time step and grid are presented as well.When β=0°,for short cylinder,the drag crisis phenomenon was also observed in the simulation,but not as obvious as in the wind tunnel test.In some attitudes,there is an obvious Kármán vortex in the wake of short cylinder and TSB.The correlation between time-averaged aerodynamic coefficients and L/D,Re,α&β is discussed.The vortex shedding frequency and shear layer behavior are obtained for quasi-steady and unsteady flow.Finally,the effect of end's shape on drag reduction and vortex shedding frequency is analyzed.     

美军建模与仿真管理特点及启示

美军是世界上唯一建立战争全域模拟仿真体系的军队,其建模与仿真建设高效管理的一些经验值得我军借鉴。本文归纳了美军建模与仿真管理5个方面的特点：高层机构统一领导,专职部门实施管理,以促进协作和共享为重点,规范化管理,模型、数据与服务一体化管理。并针对我军建模与仿真应用领域不广、协作共享不够、数据与服务管理欠缺的问题,提出了相应的建议。     

模糊理论在导弹系统故障诊断中的应用

任何系统的故障都有一定的模糊性,因此模糊理论在故障诊断中有着广泛的应用.模糊故障诊断有利于提高系统的故障诊断的水平,本文以模糊理论知识为基础,建立了系统的模糊故障诊断模型,并应用于某型号导弹武器系统的故障诊断中,结果证明该模型的有效性和合理性.     

一个监控式局部自主机器人控制器的实现与分析

本文介绍了一个严格监督控制（Ｓｕｐｅｒｖｉｓｏｒｙｃｏｎｔｒｏｌ）定义下的局部自主机器人控制器ＧＫＤ３的设计和实现，并从监督控制理论的角度，对ＧＫＤ３的体系结构和功能进行了分析和讨论。     

语音总体效能的计算机客观评价方法研究

多媒体界面中的语音评价问题尚处于研究阶段。本文探讨了语音评价的基本方法，重点对语音的客观评价方法进行研究，提出了一种应用语音分析技术进行语音总体效能客观评价的计算机处理方法。     

基于设计体模型的产品数据管理技术

针对电子系统和设备设计的需要，本文提出一种面向产品对象的数据模型——设计体模型。阐述了产品数据的配置管理和版本管理的实施策略。     

Applying Lanchester's linear law to model the Ardennes campaign

In modern warfare, many believe the decisive factor in winning a battle is seizing the right moment to shift from defense to attack, or vice versa. This paper attempts to bring that perspective to Lanchester's differential equations of warfare, and continues the application of Lanchester's linear law to the analysis of the World War II battle of Ardennes, as reported in earlier issues of Naval Research Logistics by Bracken and by Fricker. A new variable, shift time, accounting for the timing of the shift between defense and attack is explicitly included in our version of the model, and it helps obtain improved goodness of fit to historical data. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48:653–661, 2001     

基于AHP和模糊数学的课程评估系统初探

给出课程评估的因素和指标体系,提出模糊数学与AHP相结合进行课程综合评价的原理与方法,使对问题的定性分析与定量分析得到有机结合,评估结果科学合理.     

基于工控机的导弹指令系数测量方法

指令系数是防空导弹测试中比较重要的参数之一 ,通过对指令系数计算方法的分析 ,得出舵控信号起始采样时刻不会影响测量结果的结论 ,从而大大简化了测量系统的硬件结构和数据采集过程 ,提高了测量系统的稳定性 ,经过较长时间的应用表明 ,测量结果稳定性高 ,一致性好。     

General multiprocessor task scheduling

Most papers in the scheduling field assume that a job can be processed by only one machine at a time. Namely, they use a one‐job‐on‐one‐machine model. In many industry settings, this may not be an adequate model. Motivated by human resource planning, diagnosable microprocessor systems, berth allocation, and manufacturing systems that may require several resources simultaneously to process a job, we study the problem with a one‐job‐on‐multiple‐machine model. In our model, there are several alternatives that can be used to process a job. In each alternative, several machines need to process simultaneously the job assigned. Our purpose is to select an alternative for each job and then to schedule jobs to minimize the completion time of all jobs. In this paper, we provide a pseudopolynomial algorithm to solve optimally the two‐machine problem, and a combination of a fully polynomial scheme and a heuristic to solve the three‐machine problem. We then extend the results to a general m‐machine problem. Our algorithms also provide an effective lower bounding scheme which lays the foundation for solving optimally the general m‐machine problem. Furthermore, our algorithms can also be applied to solve a special case of the three‐machine problem in pseudopolynomial time. Both pseudopolynomial algorithms (for two‐machine and three‐machine problems) are much more efficient than those in the literature. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 57–74, 1999