Pickands型推广估计量的渐近正态性

极值指数在许多实际领域广泛应用:如组合投资、风险值的计算、预报地震等, 估计极值指数γ以及它的性质的研究近年来成为极值统计理论的基本问题。主要研究极值指数γ的一个估计量:Pickands型推广估计量的渐近正态性质。首先研究由Pickands型推广估计量构成的一随机过程,得到了该过程的渐近分布;然后利用研究结果证明了Pickands 型推广估计量的渐近正态性,得到其渐近方差;最后对提出的Pickands型推广估计的平滑估计量进行了相应研究。     

On lifetimes in random environments

For a component operating in random environment, whose hazard rate is assumed to be the realization of a suitable increasing stochastic process, conditions are found such that its lifetime is increasing in likelihood ratio (ILR). For the lifetimes of two components of the same kind some comparisons based on partial stochastic orders are presented. Some applications to the case of repairable components are finally provided. © 1998 John Wiley & Sons, Inc. Naval Research Logistics 45: 365–375, 1998     

超高斯随机振动环境的疲劳强化机理

针对可靠性强化试验的全轴随机振动环境的超高斯幅值分布特性开展其疲劳强化机理研究。首先通过理论分析表明RS机振动激励下试件应力仍保持超高斯分布,然后证明了同等量级下的超高斯分布比高斯分布随机应力具有更高的疲劳强化效能,从而揭示RS机全轴随机振动环境超高斯幅值分布特性的疲劳强化机理。     

关于稳定 p 型 Banach 空间中有界 Borel测度的一个定理

本文推广了Ｅ．Ｄｅｔｔｗｅｉｌｅｒ［１］关于ｐ型Ｂａｎａｃｈ空间的结论,得到了在稳定ｐ型Ｂａｎａｃｈ空间上,有界Ｂｏｒｅｌ测度为某个无穷可分ｐ稳定测度的Ｌｅｖｙ测度的一个充分条件。     

舰船航行监控变量的微机产生方法研究

通过建立舰船航行监控变量的数学模型,提出了一种基于微机的产生舰船航行监控变量的实现方法,经过实际运用表明,能有效地监视和实时控制舰船航行．     

基于改进CS的随机PRI雷达精确测速及杂波抑制算法

传统的脉冲多普勒雷达存在严重的测距测速模糊和盲区效应。考虑在正常脉冲重复间隔(PRI)上叠加一个随机扰动,并把PRI的随机变化巧妙转化为稀疏观测矩阵的受限等距性质,提出的基于压缩感知的随机脉冲重复间隔雷达为全相参动目标检测提供了一种新思路。针对其在实际应用中存在的粗糙损失和杂波干扰两个问题,分别提出了基于局部词典细化的精确测速算法和基于改进优化模型的杂波抑制方法。仿真实验结果表明该方案具有较高的测速精度和较强的杂波抑制性能。     

多点源交叉波束干涉效应特征分析

介绍多点源交叉波束通过干涉效应实现交汇空间功率合成的基本原理,根据空间功率合成机理,建立对功率合成效率、同相叠加点间距的计算机仿真,完成多点源交叉波束干涉效应特征分析,以此作为多点源交叉波束空间功率合成的评估依据。     

任意分布随机数的FPGA实现

为了满足数字电路板的随机测试需求,在Simulink/DSP Builder中建立了产生任意分布随机数的模型,并在FPGA上进行了半实物仿真和性能分析,结果表明该模型达到了设计要求,具有实用价值。     

How and why Boko Haram blossomed: examining the fatal consequences of treating a purposive terrorist organisation as less so

Boko Haram (BH) is an insurgent group that operates mainly in northeastern Nigeria. Its stated aim is to establish an Islamic state, and it employs terrorism as its strategy. Earlier interests of security analysts centred on the drivers of BH uprising and the possibility of its internationalisation. Today's concerns relate more to why the rebellion has lasted this long. In toeing the same line, this article demonstrates that BH is a purposive terror group against which the government has evolved no viable strategy. It examines some gains of BH over the past six years and how it benefitted from the government's underestimation of its capacity and determination. It concludes that to effectively engage BH, the Nigerian government must revaluate its threat and sincerely pursue an expanded strategy beyond the current military-centric approach. To be effective, government's response must be packaged in such a way as to enhance human security in the region.     

无动力运载器出水过程误差分析

无动力运载器在出水过程中受海浪的扰动作用,运动参数会产生一定的偏差。针对海浪随机性的特点,应用波能谱理论,在P-M谱基础上构建了随机海浪模型,并使用四元数法建立运载器水弹道数学模型,解决了运载器垂直出水姿态角存在的奇异性问题,通过采用二元切片法给出波浪力的计算公式。最终在Matlab/Simulink仿真工具箱下建立了运载器仿真模型,就不同海况与主浪向角影响下运载器出水的运动参数偏差进行了仿真计算,分析了其变化规律。仿真结果表明,运载器在4级海况以下各项运动参数都满足出水要求,对运载器的设计与使用具有一定的参考意义。