基于解析算法的声纳浮标搜潜系统定位精度分析

针对基于位置时间参数解析算法的声纳浮标阵搜潜系统的定位精度问题,采用定性和定量分析相结合的方法展开了研究。从解析定位模型出发,首先定性分析浮标自身的定位误差与传感器测时误差对航速及航向角计算的影响;然后选取评价指标,采用蒙特卡洛方法进行了仿真分析,得到了不同仿真条件下各个因素对定位精度具体的影响关系,这些结论为根据精度参数合理选择浮标阵的数量及布放阵型提供了依据。     

小口径速射舰炮武器系统反导射击方法研究

小口径速射舰炮受弹鼓容量及舰炮发射系统限制,一般不能在舰炮武器系统有效射击范围内全航路持续射击,这就要求对射击方法进行研究。应用蒙特卡洛法,在MATLAB软件平台上计算了小口径速射舰炮武器系统对匀速直线运动导弹的命中概率与弹丸相遇点距离间的关系,提出了以全航路最大概率命中导弹有效部位为基础制定射击终止点,反推射击起始点的射击方法,提高了舰炮武器系统在全航路射弹数限定条件下的命中概率;以舰炮武器系统跟踪器最大跟踪角速度限制因素为例,分析了导弹运动速度、航路捷径与射击区域的对应关系,并应用本方法对导弹典型航路的射击方案进行了仿真。仿真结果表明该方法在一定条件下能有效提高舰炮武器系统对导弹的全航路命中概率。     

THE F‐35 JOINT STRIKE FIGHTER AS A SOURCE OF INNOVATIon AND EMPLOYMENT: SOME INTERIM RESULTS

The F‐35 Joint Strike Fighter (JSF) programme is important for innovation in the Dutch economy and also contributes to other programmes in the aerospace industry (spin‐off) and other industries (spillover). On top of the expected value of US$9.2 billion in development and production, based on interviews with 10 companies and research institutes, an expected spin‐off of US$1.1 billion and an expected spillover of US$120 million will result. In addition, over 23,000 man‐years are associated with the activities in the development and production of the JSF. This study excludes the large and labour‐intensive Maintenance, Repair and Overhaul (MRO) activities. Further validation of data and an update of current results is planned for 2006.     

NUCLEAR WEAPONS AS THE CURRENCY OF POWER

There are important similarities between the pattern of behavior Karl Marx identified with respect to commodities—a pattern he called “fetishism”—and the pattern of behavior identified in this article with respect to military force. Marx identified money as the mature expression of commodity fetishism; the author identifies nuclear weapons as the mature expression of the fetishism of force. As such, nuclear weapons function as the currency of power in the international system. This article lays out a theory of nuclear fetishism by adapting four themes that are characteristic of the pattern of behavior known as fetishism: materiality, historicality, efficacy, and reification. By applying these categories to the fetishism of nuclear weapons, the author shows that nuclear weapons represent a new social form consistent with, yet distinct from, other fetish objects.     

基于目标舷角分布范围的拖线阵声纳左右舷分辨推理模型

被动拖曳线列阵声纳存在目标左右舷模糊的问题,现有分辨模型可能导致误判。为克服现有模型的误判问题,综合考虑目标距离、初始舷角以及本舰机动角度等重要影响因素,建立了本舰转向完成重新测得目标时目标舷角(θ1)分布范围的解算模型。基于该模型得到目标分别位于本舰左舷或右舷时目标舷角对应的分布区间1和区间2。根据区间1和区间2的不同组合以及θ1值落在区间1和区间2的不同情形,建立了拖曳线列阵声纳左右舷的新模型。最后,实例验证了模型的适用性和正确性。     

一种基于层次分析法的舰炮武器系统选型综合评价模型

针对舰炮武器系统选型配置决策中众多制约因素难以平衡兼顾的难题,本文基于层次分析法,综合了作战效能、全寿命周期费用、研制周期、适装性、技术可行性和发展潜力等多变量因素,提出并建立了一套综合优化舰炮武器系统选型配置方案的方法和模型,实现了舰炮武器系统选型配置问题的优化决策,最后以大口径主炮武器系统发展选型为例,给出了模型的应用实例。     

SINS/GNSS自适应反馈校正滤波

SINS/GNSS组合导航中,反馈闭环校正比开环输出具有更高的短时精度;但反馈校正的输出会有长时间缓慢发散迹象。传统工程上应用最优奇异值可观测度对反馈向量进行自适应调整,但最优奇异值计算量很大,且不同机动情形下的最优奇异值也不相同,很难确定。通过分析卡尔曼滤波的方差矩阵,提出一种新的可观测度定义,并利用滤波协方差矩阵确定新的可观测度,并结合人工神经网络确定反馈校正的自适应调整系数,仿真表明新方法抑制了反馈校正输出误差的长时缓慢发散,提升了导航精度。     

弹性高超声速飞行器自适应极点配置控制

本文针对乘波体外形的高超声速飞行器存在的结构/推进/气动强耦合特性,利用鲁棒极点配置方法设计了自适应控制器,实现了对高超声速飞行器的速度和高度指令跟踪控制。控制器采用了Proportional-Integral-Filter(PIF)结构,该结构的控制器不仅能够使系统具备良好的稳态特性而且能够对控制信号进行滤波平滑,从而能够有效地抑制高超声速飞行器的弹性振动对控制系统的影响。基于弹性高超声速飞行器模型CSUAL_GHV,分别采用自适应鲁棒极点配置控制方法和自适应非鲁棒极点配置控制方法进行了数值仿真。结果表明,与非鲁棒极点配置控制方法相比,采用自适应鲁棒极点配置控制方法的控制系统不仅使飞行器能够很快地跟踪上速度和高度指令,跟踪误差小于1%,而且高超声速飞行器的弹性振动也得到了有效地抑制。飞行器在整个飞行过程中的飞行攻角均处于±2°范围内,满足超燃冲压发动机的工作要求。     

‘The only good jihadist is a dead jihadist’:Boko Haram and de-radicalization around Lake Chad

ABSTRACT

This article discusses the shortcomings of the “de-radicalization doctrine” in sub-Saharan Africa. The issues raised are illustrated by the war against Boko Haram, which involves Nigeria, Niger, Chad and Cameroon. Relying on interviews with security officers, insurgents, civil servants, displaced people, humanitarian workers and Muslim and Christian clerics in Nigeria, Niger and Chad since 2005, the investigation shows that the four states focused on repression rather than demobilisation programs in prison or outdoors. The Boko Haram crisis is mainly a story of mismanagement. The article thus challenges the assumptions of the “de-radicalization doctrine” in Muslim Africa South of the Sahara. First, attempts to de-radicalize jihadi terrorists tend to focus too much on religious fanaticism and the exegesis of the Quran. Secondly, they are neither feasible nor efficient. Finally, they obscure priorities that are more important to counter extremism and demobilize insurgents.