用于卫星干扰源定位的压缩感知DOA估计方法

针对传统测向方法的实际应用性能较差,提出一种基于压缩感知(CS)的卫星干扰源定位方法。根据干扰信号方位角的空间稀疏性,建立了压缩感知波达方向(DOA)估计模型。通过协方差矩阵的高阶幂逼近信号子空间和矩阵的共轭对称特征,利用高阶幂矩阵的主对角线下左下角列向量进行波达方向估计。仿真实验验证,该方法不需要已知干扰源数,具有较高的精度和较好的分辨力,且能满足对相干干扰信号的估计。对压缩感知DOA估计在卫星干扰源定位中的应用具有一定参考意义。     

基于高阶谱分析的机械故障特征识别

在分析高阶累积量与高阶谱的理论基础上,利用高阶谱可以抑制加性高斯噪声的性质,研究了基于高阶谱分析的机械故障特征提取方法,提出了基于双谱估计的齿轮故障诊断的方法。通过对齿轮信号的双谱特征图谱进行分析比较,成功地对齿轮的正常稳态振动信号、正常瞬态振动信号以及磨损瞬态信号进行了识别,效果十分显著。     

规范火场战斗秩序的实践与思考

分析当前火场战斗秩序混乱的原因,从火灾现场排兵布阵、灭火救援绩效考评和人才保障等方面提出了规范火场战斗秩序,提高灭火实战能力的相应对策。     

On the application and extension of system signatures in engineering reliability

Following a review of the basic ideas in structural reliability, including signature‐based representation and preservation theorems for systems whose components have independent and identically distributed (i.i.d.) lifetimes, extensions that apply to the comparison of coherent systems of different sizes, and stochastic mixtures of them, are obtained. It is then shown that these results may be extended to vectors of exchangeable random lifetimes. In particular, for arbitrary systems of sizes m < n with exchangeable component lifetimes, it is shown that the distribution of an m‐component system's lifetime can be written as a mixture of the distributions of k‐out‐of‐n systems. When the system has n components, the vector of coefficients in this mixture representation is precisely the signature of the system defined in Samaniego, IEEE Trans Reliabil R–34 (1985) 69–72. These mixture representations are then used to obtain new stochastic ordering properties for coherent or mixed systems of different sizes. © 2008 Wiley Periodicals, Inc. Naval Research Logistics, 2008     

kittel型反铁电相变的自由能

根据kittel型反铁电相变对称性的变化 ,选择轴矢量 R作为序参量是合适的。由Landau理论 ,相变温度附近的自由能F就可以写成 R幂级数展开的形式。令 F R=0 ,可得到关于序参量的方程 ,从而获得相变温度与自由能的关系     

凸度量空间中广义拟-压缩映象的不动点的逼近问题

设 (E ,d ,W )是完备的凸度量空间 ,T :E→E是广义拟—压缩映象 ,{xn}为T的带误差项的Ishikawa迭代序列。则 {xn}收敛于T的唯一的不动点 p∈E。     

Signature based analysis of m‐Consecutive‐k‐out‐of‐n: F systems with exchangeable components

In this article, we study reliability properties of m‐consecutive‐k‐out‐of‐n: F systems with exchangeable components. We deduce exact formulae and recurrence relations for the signature of the system. Closed form expressions for the survival function and the lifetime distribution as a mixture of the distribution of order statistics are established as well. These representations facilitate the computation of several reliability characteristics of the system for a given exchangeable joint distribution or survival function. Finally, we provide signature‐based stochastic ordering results for the system's lifetime and investigate the IFR preservation property under the formulation of m‐consecutive‐k‐out‐of‐n: F systems. © 2011 Wiley Periodicals, Inc. Naval Research Logistics, 2011     

高层建筑加压防烟设计主要问题研究

从设计环节出发,针对加压防烟设计中出现频率较高的风机压头、风道内壁的绝对粗糙度、竖向风道断面长宽比、断面风速选择、风机特性选择等几个主要问题进行了分析,并提出应对措施,为今后的加压防烟设计提供参考。     

边防武警执行命令行为的性质定位

边防武警具有军人和警察的双重属性,因此,其执行命令行为在性质上不同于普通的军事命令,而体现出一定的行政性特征。边防武警执行命令行为的性质定位直接关系到其执行多样化军事任务中各项行为的法律后果,具有重要的理论意义和司法实践意义。     

基于二阶锥规划的MIMO雷达任意形状旁瓣波束设计

针对MIMO雷达非均匀布阵引起的高旁瓣问题,提出一种基于二阶锥规划的任意形状旁瓣设计算法.算法通过在旁瓣区域附加多个二次不等式约束,从而有效抑制干扰、保持期望方向天线增益的同时,获得了期望的、可以任意控制的旁瓣波束响应.通过将优化模型转化为凸二阶锥规划问题,利用内点法可以得到有效求解.仿真试验表明:算法能够获得任意形状期望旁瓣波束设计的同时,有效提高了波束形成器的输出信干燥比.最后计算机仿真结果证实了算法的有效性和可行性.