Note: Two rendezvous search problems on the line

A new upper bound is obtained for the two‐person symmetric rendezvous value on the real line when the distribution function of their initial distance apart is bounded. A second result shows that if three players are placed randomly on adjacent integers on the real line facing in random directions and able to move at a speed of at most 1, then they can ensure a three‐way meeting time of at most 7/2; the fact that 7/2 is a best possible result follows from work already in the literature. © 1999 John Wiley & Sons, Inc. Naval Research Logistics 46: 335–340, 1999     

基于多通道雷达的对侦察接收机截获距离压制设计

低截获概率(LPI)雷达为了达到低截获的目的,雷达通常会采取很多措施,包括可变的重频,复杂的脉内调制,甚至于载频捷变等等,但是,从根本上来说,这些措施只是增加了侦察机的分选识别难度,间接地降低截获概率,真正想要获得很好的低截获概率,通常需要雷达控制探测距离。在LPI雷达作用距离不变的条件下,采用多通道的设计方法,根据灵敏度的计算给出了获得较大安全探测距离的方法,从而压制侦察接收机的截获距离。     

采用终端滑模控制实现交会对接逼近段姿态跟踪

针对交会对接逼近段追踪器的姿态控制问题,采用反馈线性化理论推导了非线性姿态动力学方程的相变量模型.基于导出的姿控模型,引入模型误差和随机噪声,结合终端滑模控制理论,给出了能够在有限时间内完成姿态跟踪,并使状态跟踪误差收敛的控制律的设计方法.对具有扰动项的系统,仿真结果仍能满足交会任务对时间的要求,且姿态角跟踪误差趋于0,说明控制律对相变量系统的姿态跟踪控制具有较好的鲁棒性.     

The Provisional IRA,the Irish border,and Anglo-Irish relations during the Troubles

Using hitherto largely unexplored governmental archives from London and Dublin, this article focuses on the security challenges arising from the existence of the land frontier between the Republic of Ireland and Northern Ireland and the significance of issues of cross-border security cooperation for Anglo-Irish relations from the beginning of the Troubles until the Anglo-Irish Agreement in 1985. It argues that the relatively safe haven of the Republic was essential to the longevity of the IRA's campaign and that successive Irish governments exploited British security concerns to expand their political influence on Northern Ireland.     

要地防空导弹飞行试验指挥显示系统的设计

通过对靶场导弹飞行试验发射阵地指挥显示系统的介绍,阐明了试验指挥系统设计的思路、显示内容、建立原则和实现方法,其中重点对系统相关设计和技术实现方法进行了详细阐述。     

连续不间断高层建筑快速逃生装置的设计与应用研究

高层建筑数量增多的同时,其人员安全疏散问题日益凸显,研究高层建筑受困人员火灾情况下的自救逃生和连续疏散非常重要。结合国内外高层建筑逃生装置研究现状和存在的主要问题,研究设计了连续不间断高层建筑快速逃生装置的结构,分析了其结构设计特点,并与传统救援设备进行了性能对比分析。针对国内高层建筑火灾形势,探讨了该装置在高层建筑受困人员快速、多人连续逃生方面的优势和应用前景。     

我国部分城市大型商业综合体消防设计案例分析

通过对全国部分城市大型商业综合体消防安全设计的实地调研分析,总结了我国当前对大型商业综合体消防设计的几种不同解决方案。通过综合比较分析,给出了科学解决大型商业综合体消防安全的基本模式,并为防火规范的进一步修订,提供了案例和建议。     

基于循环追踪算法的编队航天器交会控制

采用循环追踪算法解决编队航天器交会控制问题。建立并推导了线性循环追踪算法和非线性循环追踪算法数学模型,提出了绕飞平面采用循环追踪控制,绕飞平面法向采用比例微分进行振动抑制的编队交会控制律。基于脉冲推力方式,对绕飞平面分别采用线性和非线性循环追踪的三航天器编队交会控制问题进行了仿真分析。仿真结果表明,提出的基于循环追踪的控制方式可满足编队航天器交会控制要求,航天器按顺时针运行轨迹交会于初始位置决定的参考中心,三航天器间相对距离、相对运动速度变化趋势基本一致,速度增量消耗较小,为航天器编队构形控制研究提供有益参考。     

针对突发威胁的无人机多机协同路径规划的方法

在无人机多机协同路径规划中,采用V orono i图方法,引入协同变量和协同函数,产生关于已知威胁的路径,使各架无人机能够同时到达目标。在此基础上,利用集合点规划状态图,针对作战过程中的突发威胁实时进行路径规划,从而得到各架飞机的几何路径。仿真结果表明集合点规划状态图的使用对于无人机多机协同路径规划中的突发威胁问题的求解是有效的。     

Rendezvous search when marks are left at the starting points

Leaving marks at the starting points in a rendezvous search problem may provide the players with important information. Many of the standard rendezvous search problems are investigated under this new framework which we call markstart rendezvous search. Somewhat surprisingly, the relative difficulties of analysing problems in the two scenarios differ from problem to problem. Symmetric rendezvous on the line seems to be more tractable in the new setting whereas asymmetric rendezvous on the line when the initial distance is chosen by means of a convex distribution appears easier to analyse in the original setting. Results are also obtained for markstart rendezvous on complete graphs and on the line when the players' initial distance is given by an unknown probability distribution. © 2001 John Wiley & Sons, Inc. Naval Research Logistics 48: 722–731, 2001