The structure of the defense industry and the security needs of the country: a differentiated products model

This paper models the interactions between the defense needs of the USA and Western Europe, which produce several heterogeneous defense goods, and the defense industry market structure. The results show that net defense costs of the USA and Europe are lower when the number of defense firms in each arms‐producing country is small and when the world prices of the defense goods are high. The model predicts that the increase in world prices will crowd‐out countries in the developing world from the market for modern weapon systems and may force them to develop and use ‘cheap and dirty’ weapon systems.     

Does Geopolitical Risks Predict Stock Returns and Volatility of Leading Defense Companies? Evidence from a Nonparametric Approach

Abstract

We use the k-th-order nonparametric causality test at monthly frequency over the period of 1985:1 to 2016:06 to analyze whether geopolitical risks can predict movements in stock returns and volatility of 24 global defense firms. The nonparametric approach controls for the existing misspecification of a linear framework of causality, and hence, the mild evidence of causality obtained under the standard Granger tests cannot be relied upon. When we apply the nonparametric test, we find that there is no evidence of predictability of stock returns of these defense companies emanating from the geopolitical risk measure. However, the geopolitical risk index does predict realized volatility in 50% of the companies. Our results indicate that while global geopolitical events over a period of time is less likely to predict returns, such global risks are more inclined in affecting future risk profile of defense firms.     

ESCAPE FROM NUCLEAR DETERRENCE

Since the post-World War II genesis of nuclear deterrence, two presidential initiatives have been presented to deliver humanity from the threat of its failure. The first was the Strategic Defense Initiative (SDI), a constellation of space- and ground-based systems that President Ronald Reagan envisioned would render nuclear weapons “impotent and obsolete.” The second is President Barack Obama's roadmap to “a world without nuclear weapons,” commonly referred to as “Global Zero.” While these proposals appear to have little in common, deeper investigation reveals a number of provocative similarities in motivation and presentation. Moreover, both generated fierce debate, often with ideological overtones, about their strategic desirability and technical feasibility. We use these parallels, as well as prominent dissimilarities, to draw lessons from the SDI experience that can be applied to the debate over Global Zero.     

基于奇异值分解的潜艇磁场推算

针对潜艇磁性防护,基于磁偶极子阵列模型,建立了潜艇磁性目标高精度磁场计算模型。提出了利用奇异值分解的方法对模型进行求解,利用该求解算法进行了模型计算与实测数据比对,结果表明,该计算方法能够有效适用于计算高精度潜艇磁场。基于奇异分解的方法计算了潜艇高空磁场,计算结果可供潜艇防护磁性探测参考。     

基于多Agent的网络防御建模与仿真

为了提高网络防御建模的有效性,本文提出了应用多Agent对网络防御进行建模的方法。并且分析了多Agent的建模仿真流程,通过多Agent建模仿真方法,建立了分布式拒绝服务攻击的防御模型。最后,用Netlogo软件进行了仿真实验,通过仿真结果验证了防御模型的有效性。     

防空兵网络化作战指挥控制方式

信息化条件下防空兵作战依托防空兵指挥信息系统,已经将防空兵各个作战要素联结到了一起,初步具备了网络化作战的雏形.而恰当的指挥控制方式是实施高效防空兵网络化作战的关键问题之一.首先剖析了防空兵网络化作战给指挥控制带来的新特点,而后构建了防空兵网络化作战指挥控制方式的概念模型,在此基础上提出了适应防空兵网络化作战的指挥控制方式是自适应指挥控制方式.并研究了防空兵网络化作战实施自适应指挥控制方式的必要性、可行性、内在机理以及实现的途径.     

基于微分几何与李群的无人机编队会合方法

在领航-跟随编队模式下,设计了一种基于追缉策略的无人机编队会合方法。首先,基于微分几何曲线论和弗雷涅-塞雷标架建立了无人机非解耦三维运动模型,其中将曲率和挠率作为控制量;结合该模型给出了无人机三维编队会合问题的数学描述,它将导弹制导问题中的终端落角约束映射为编队会合问题中僚机的航迹倾角约束,同时引入额外的航迹方位角约束;然后使用特殊正交群的元素来度量长僚机方向偏差,并通过局部坐标映射将其映射为对应李代数空间中的旋量;接着,基于该旋量设计了编队会合几何导引律,并给出相应的曲率和挠率控制指令;最后,分别在长机稳定平飞和转弯机动条件下进行了多机编队会合数字仿真实验,仿真结果显示僚机能够有效地跟踪长机航向并收敛至指定位形,说明了方法的有效性。     

基于飞蛾信息素寻偶机制的无人机集群协同搜索

为了提高无人机集群协同搜索移动目标的效率,提出一种基于飞蛾信息素寻偶机制的无人机集群协同搜索方法。根据飞蛾基于信息素选择飞行方向的寻偶行为,建立信息素图风向模型和飞蛾信息素寻偶模型。考虑无人机机间避撞约束,提出从飞蛾信息素寻偶机制到无人机集群分布式协同搜索的映射,并给出具体实现流程。仿真实验结果表明了所提方法在解决单个移动目标的协同搜索问题时的有效性和稳定性;外场飞行试验表明了所提方法在实际应用中的可行性。     

多旋翼无人机模型预测抗扰避障制导

多旋翼无人机的自主避障是完成复杂任务的基础,避障的效果直接影响无人机执行任务的效能。针对存在外部扰动的无人机避障问题,提出了一种基于模型预测的抗扰避障制导律设计方法。通过设计干扰观测器对系统动态中的外部干扰进行了估计,并基于李雅普诺夫函数方法设计辅助制导律用于建立稳定性约束条件。结合前两者与模型预测控制,在模型预测控制优化求解中考虑无人机与障碍物的关系,根据所设计的制导律求解水平线速度与偏航角速度指令实现无人机的避障。对所提出的避障制导律进行数值〖BHDWG8,WK10YQ,DK1*2,WK1*2D〗〖XCLQX.TIF;%129%129〗听语音 聊科研与作者互动 仿真和实物飞行验证,结果表明了所提方法的有效性。     

India's Pursuit Of Ballistic Missile Defense

This article analyzes India's efforts to deploy a Ballistic Missile Program (BMD). The article has three objectives. First, it argues that scientific-bureaucratic factors and India's incapacity to deter Pakistan's use of terrorist proxies have driven its quest for BMD. Second, the article also evaluates the current state of India's two-tiered missile defense shield. In spite of various claims on the part of India's defense science establishment, the paper estimates that India still lacks a deployable BMD system and is still far from developing an effective strategy of deterrence-through-denial. Third, the article analyzes the implications of the development of India's BMD system for nuclear stability in South Asia. The article shows how India's BMD capacities, however limited, have indirectly exacerbated the security concerns of India's regional rival, Pakistan.