基于Golay互补序列的UWB同步和信道估计

提出了一种基于Golay互补序列的UWB信道估计和同步方法。该方法利用了Golay互补序列所具有的互补的自相关特性。首先引出了Golay互补序列的插0序列的概念,并证明了这种插0序列也是Golay互补序列。通过依次发送Golay互补序列,在接收端采样后分别与相应Golay插0序列进行相关并求两者和,根据门限判别即可完成同步和信道估计,仿真结果表明了该方法是有效的。     

平衡型PN序列的一种构造方案

根据混沌结构下PN序列的生成方案,本文对生成平衡型PN序列的相关特性进行了研究,实测表明所生成序列具有良好的自相关和互相关特性,同时该序列还有接近理想的线性复杂度,具备相当的实用价值,为PN序列的选择提供了新的途径。     

中国国防费时间序列预测模型构建

文章综合运用B-J时间序列建模方法,对中国国防费时间序列平稳性进行了判别;采用单位根方法检验了时间序列的单整阶数;利用自相关函数和偏自相关函数判别了时间序列模型的自回归阶数(AR(p))和移动平均阶数(MA(q));构建了中国国防费时间序列模型,并进行了分析和预测。     

混沌序列相关特性研究及在扩频通信中的应用

分别用Logistic映射和Chebyshev映射产生出混沌序列,在Matlab下进行相关性分析,再以Chebyshev映射产生的混沌序列代替传统的伪随机序列作为扩频通信系统的扩频码,在Simulink下进行扩频通信系统的仿真,综合分析了基于混沌序列的扩频系统的抗噪性能,仿真结果验证了基于混沌序列的扩频系统的抗干扰性能和混沌序列作为码的应用价值.     

直接序列扩频通信抗干扰性能分析

简述了直接序列扩频通信基本原理,讨论了直接序列扩频通信的特点,对直接序列扩频通信系统的抗干扰能力进行研究,最后提出了几种用于提高该通信系统抗干扰能力的具体方法。     

军用卫星系统中混沌直扩码序列的研究

本文根据单峰映射产生混沌序列极易被攻击的特点,采用高维的混沌系统来设计混沌扩频序列。针对n维非线性数字滤波器产生序列的周期和分布特性,我们在结构上作了相应的设计。产生序列的数值分析表明：其性能与理想随机序列一致,与传统扩频序列相当。由于混沌扩频序列具有周期任意、码族数目多、保密性好等优点,特别适合在军事卫星扩频系统中应用。     

基于复合约束的作战行动序列生成与执行控制方法

作战行动序列是作战计划的核心,也是指挥控制的关键.传统的作战行动序列制定主要通过手工方式,效率低下且耗时费力,难以满足现代战争筹划需要,作战行动序列执行控制也缺乏现代信息手段支撑.提出了一种基于时间、空间和因果复合约束条件的作战行动序列生成与执行控制方法,提高了作战计划方案中作战行动序列生成效率,通过对时间、空间、作战效果状态监测对作战行动序列执行进行辅助控制,为指挥员基于网络信息体系进行指挥决策提供了条件支撑.     

基于BP神经网络的极移预报*

为了提高地球定向参数极移的预报精度,建立了一个极移数据预报模型。利用傅里叶分析研究插值基础序列的周期特性,验证了基础序列重采样的可行性,提取插值基础序列数据的趋势项,利用多输入-单输出BP神经网络建模预报不同跨度的残差序列,合并趋势项和残差序列得到最终的极移预报。预报结果表明,选取合适的插值基础序列得到的预报极移精度较高,此BP神经网络能够有效地应用于地球定向参数极移的预报。     

基于双混沌系统伪随机比特发生器的研究

研究了基于双混沌系统伪随机比特发生器(CCS-PRBG)生成序列的密码学性质,证明了此二进制序列是i.i.d.序列。理论分析表明,CCS-PRBG可生成具有理想保密性的二进制混沌密码序列。     

基于混沌序列的动态双频跳频同步方案

跳频通信系统的关键技术是跳频序列的同步。利用混沌序列作跳频码,取代了跳频通信中常见的伪随机序列。为了解决混沌跳频序列的同步难题,提出了一个以动态双频构建跳频序列同步的新方案。利用M atlab下S im u link仿真平台,对动态双频同步方案进行建模与仿真,结果表明该同步方案用于跳频通信可获得满意的通信效果。     

Reviews

Douglas S. Derrer, We Are All the Target: A Handbook of Terrorism Avoidance and Hostage Survival. Annapolis, MD: US Naval Institute Press, 1992. Pp. x+135, notes, index. $14.95. ISBN 01–55750–150–5

Ian Knight, Zulu: Isandlwana and Rorke's Drift, 22–23 January 1879. London: Windrow & Greene, 1992. Pp.136, 150 illus., incl 8 colour plates, maps, biblio. £35. ISBN 1–872004–23–7

Ian Knight, By the Orders of the Great White Queen: Campaigning in Zululand through the Eyes of the British Soldiers, 1879. London: Greenhill Books and Novato: Presidio Press, 1992. Pp. 272, 17 illus., 1 map. £18.95. ISBN 1–85367–122–3

Manfried Rauchensteiner and Erwin A. Schmidl (eds.), Formen des Krieges: vom Mittelalter zum ‘Low‐intensity’ Conflict’. Graz : Verlag Styria, 1991. Pp.208. DM35. ISBN 3–22–12139–7

Harold J. Kearsley, Maritime Power and the Twenty‐First Century. Dartmouth: Dartmouth Publishing Company, Limited, 1992. Pp.xv + 203, 13 diagrams, index. £32.50. ISBN 1–85521–288–9     

Panjwai: a tale of two COINs in Afghanistan

The US Army has two approaches to counterinsurgency operations in Afghanistan. One is hard, or combat-focused, and the other is soft, or development-focused. This study examines two US Army task forces deployed to Panjwai District, Afghanistan from 2012 to 2013. CTF 4-9 and 1-38 offer a meaningful comparison because they pursued these contrasting approaches among the same population and against the same enemy at the same time and place. The study compares each unit’s approach and finds that neither approach was successful absent the other. The article concludes by recommending further research into combining the approaches at the operational level.     

线性核时频信号表示及其仿真

根据ｃｈｉｒｐ信号在模糊域的特点,本文提出了线性核时频表示方法。这种方法在提高分辨率、消除交叉项以及抑制噪声等方面都具有较高的性能。理论分析和实验结果都证实了这种方法的有效性     

Putin – the masked nemesis of the strategy of ambiguity

Recent events demonstrate the complex and adaptive approach employed by Russia to reassert influence in Europe. The changing face of Russia’s strategy commenced in 2007 when it launched a crippling cyber-attack against Estonia. This was followed by a large Russian conventional attack against Georgia in 2008, occupying two large areas of the nation. 2014 witnessed the Russian annexation of Crimea where in just a week, Russia seized control of Crimea “without firing a shot.” The annexation of Crimea was rapidly followed by a Russian inspired and led subversive war in eastern Ukraine. The common thread among these diverse Russian operations is its use of ambiguity to confound and confuse decision makers in the West.     

Forecasting a Hurricane: Israeli and American Estimations of the Khomeini Revolution

The surprising ‘Arab Spring’ raises the question as to what would enable national intelligence to provide high quality warnings prior to the eruption of popular revolutions. This article uses new sources of evidence to trace and explain Israel's success in comparison to US failure at correctly estimating the course of the Iranian Revolution in 1977–79. In explaining this variance, the article shows that it was mainly the result of the intimate acquaintance of Israel's representatives in Iran with the local language, history and culture, as well as the ability to communicate with locals – tools which the Americans completely lacked.     

关于教师继续教育培训模式的思考

继续教育作为终身教育的重要组成部分和基本形式,对教师的发展成长意义重大。继续教育工作开展十多年来,取得了一定的成绩,但还存在不少问题,如学习动机较为被动,管理认识不到位,教学内容陈旧空泛,教学方法呆板机械等。随着课程改革的不断深入,继续教育必须采取相应的改进措施,树立以人为本,服务至上的观点,教学内容的前瞻性与实用性并重,教学人员进行整合,教学方法灵活多样,评价考核规范科学等,以此激活受训教师内在的学习动机,更大程度地提高继续教育培训的实际效果。     

用DirectShow实现网络视频

目前市场上的网络监控技术一般用昂贵的硬件设备来支撑,投资较大。在深入研究微软的DirectX9.0的基础上,提出如何用DirectShow软件技术和普通的数字摄像头来实现网络视频的监控和实现技术,内容涉及通信协议、视频的编码与解码技术、视频的编码格式和COM组件编程技术等,最终的实验结果令人满意,且费用低廉,技术可靠,为在高速局域网内构建视频监控系统提供有效的技术支持。     

Interpreting the Ribchester Helmet

In 1796 a 13-year-old boy playing on wasteland behind his father’s house in Ribchester, Lancashire discovered an assemblage of over 30 Roman artefacts, including a decorated brass helmet. Although partially corroded the Ribchester helmet is a fine example of a first-century AD cavalry sports helmet. This article considers how the interpretation of the helmet has evolved since its discovery. The multi-faceted iconography of the helmet with its mural crown diadem is that of an elite soldier and is paralleled in other examples of cavalry sports helmets of the Ribchester type. The long-neglected imagery on the helmet bowl is reinterpreted and seen not as a haphazard collection of randomly placed combatants but as a highly structured, symmetrical composition specifically designed to be viewed from different directions.     

Desert insurgency: lessons from the third Tuareg rebellion

This article provides an in-depth examination and analysis of the 2006–2009 Tuareg rebellion in Mali and Niger. It identifies the underlying reasons behind the rebellion, explores contrasting counter-insurgency (COIN) strategies employed by the two governments, and presents some lessons learned. While both COIN approaches ultimately produced similar peace settlements, the article argues that the Malian strategy of reconciliation combined with the selective use of force was far more effective than the Nigerien iron fist approach at limiting the size and scope of the insurgency and producing a more sustainable peace. It concludes by looking at the role of external actors, particularly the United States, and how the failure to internationalize the conflict was actually more beneficial to the local COIN effort, as well as to the longer strategic interests of the United States in the region.