基于矩阵的C4ISR系统结构设计评价

主要目的是提出两种矩阵方法对C4ISR系统结构进行评价.其中邻接矩阵法用于评价C4ISR系统之间的互连互通性,对于评价规模较大、结构复杂的系统结构较为适用;模糊矩阵法用于评价系统之间的相似性,通过科学的评价指标体系消除系统之间的冗余.这些方法是当前主流的经验评价方法(如ATAM方法)的有效补充,具有一定的科学性和合理性.最后分别给出了两种方法的一个应用实例,体现了其在工程实践上的价值.     

整环上不定方程组的通解公式及其应用

借助Z上矩阵A∈Mm×n(Z)的标准形式D=VAU=diag(d1,d2,…,dq,0,…,0),得到了整环上不定方程组AX=B的通解公式以及矩阵初等变换法.     

基于时滞分割法的具有leakage项时滞的离散型神经网络状态估计

摘要：研究一类具有leakage时滞的离散型神经网络的状态估计问题．通过构造新的Lyapunov泛函得到保证估计误差全局渐近稳定的充分条件,并通过求解一个线性矩阵不等式（LMI）得到状态估计器的增益矩阵．采用一种新的时滞分割方法将变时滞区间分割为多个子区间,使该结果在获得更小的保守性同时也降低了计算的复杂度．     

GPS接收信号中线性扫频干扰的抑制

研究了阵列接收的GPS接收信号中线性扫频(LFM)干扰的抑制问题。LFM信号瞬时频率的估计是抑制干扰的关键,而要准确估计信号瞬时频率,必须抑制接收信号时频分布中交叉项干扰。本文对接收信号矢量进行白化,得到信号矢量白化后的空时频分布(STFD)矩阵。文中推出一个与传统方法获得的判决变量不同的判决变量,用该判决变量可以更加清晰地选出LFM信号在时频分布中的自项。根据时频脊点的分布估计LFM信号频率参数以及信号瞬时频率,之后即可根据瞬时频率构建陷波器滤除干扰。仿真表明该方法能够将受交叉项严重干扰的接收信号时频分布映射为清晰的接收信号自项的时频分布,在数据快拍数满足一定要求时可以很好地抑制掉LFM干扰。     

结合流形滤波的矩阵信息几何检测器

针对小样本、非均匀杂波下的信号检测问题,提出一种基于流形滤波的矩阵信息几何检测器,将信号检测问题转化为矩阵流形上的几何问题。将每一个样本的相关性数据建模为一个托普利兹正定矩阵,在此基础上,利用每一个样本数据的邻近矩阵进行加权平滑滤波,去除一部分杂波能量,提升目标与杂波间的区分性。计算了辅助样本数据对应矩阵的几何均值,通过比较待检测样本数据矩阵与几何均值矩阵之间的距离与检测门限的大小,以实现信号检测。实验结果表明,与自适应匹配滤波相比,本文方法在小样本、非均匀杂波下具有明显的性能优势。     

钢丝增强复合条带抗弹性能数值分析

为研究钢丝增强聚合物基复合条带的抗弹性能,基于冲击动力学理论分析其抗弹机理,再借助ANSYS/LS-DYNA软件和LS-PrePost前后处理器模拟有无增强钢丝2种工况下,条带对7.62 mm弹体的冲击响应。分析表明：条带的弹性模量、剪切模量和面密度会影响其能量吸收性能,能量吸收量随三者的增大而增大;由于聚合物基体的正交各向异性,应力云图显示出扁平椭圆状是合理的;在聚合物基复合条带中嵌入增强钢丝对条带整体的抗弹性能有积极的影响,但嵌入过量的钢丝会导致重量和成本的增加,因此需要对合理的钢丝配比率作进一步研究。研究结果可为钢丝增强聚合物基复合条带在野战防护结构中的应用提供参考。     

Effect of nano powder (Al2O3-CaO) addition on the mechanical properties of the polymer blend matrix composite

This work describes the preparation and study of the properties of composite nanoparticles prepared by the sol-gel method which consists of two materials (Al₂O₃-CaO), and study the effect of these nanoparticles on the mechanical behavior of a polymer blend (EP 4% + 96% UPE). The powder was evaluated by X-ray diffraction analysis, scanning electron microscopy analysis (SEM), particle size analysis, and energy dispersive X-ray analysis (EDX). The mechanical behavior of the composite material was assessed by tensile test, bending test and hardness test. The evaluation results of the composite nanoparticles showed good distribution of the chemical composition between aluminum oxide and calcium oxide, smoothness in particles' size at calcination in high and low temperatures, formation of different shapes of nanoparticles and different (kappa and gamma) phases of the Al₂O₃ particles. The results of mechanical behavior tests showed marked improvement in the mechanical properties of the resulted composite material, especially at 1.5%, compared with polymer blend material without nano powder addition. The tensile properties improved about (24 and 14.9) % and bending resistance about (23.5 and 16.8) % and hardness by (25 and 22) % when adding particles of size (63.8 and 68.6) respectively. Therefore, this reflects the efficiency of the proposed method to manufacture the nanocomposite powder and the possibility of using this powder as a strengthening material for the composite materials and using these composite materials in bio applications, especially in the fabrication of artificial limbs.     

干扰抑制类生成式对抗网络

为进一步改善超低频频段的通信质量,在传统改进广义旁瓣抵消算法的基础上,提出新的超低频干扰抑制算法——生成式旁瓣抵消算法。该算法将人工智能研究热点之一的生成式对抗网络模型引入广义旁瓣抵消算法中,通过优化设计生成模型的网络结构及相关超参数,有效地解决了原算法存在的期望信号残留问题,为旁瓣抵消通道中的后级滤波算法提供了与主通道相关性更强的干扰参考信息,从而提高了算法对主通道干扰估计的准确性。为了验证优化后生成模型的有效性以及所提算法对不同类别干扰的抑制能力,在实验室环境下搭建实验平台,设计了多组对照实验。实验结果表明:优化后的生成模型具有较好的生成能力、较好的鲁棒性以及相对较低的运算复杂度;相比于传统改进的广义旁瓣抵消算法,所提算法进一步提高了信号带宽内的信干噪比。     

Optimal allocation of minimal repairs in parallel and series systems

In reliability engineering, the concept of minimal repair describes that the repair brings the failed unit (eg, system or component) to the situation which is same as it was just before the failure. With the help of the well‐known Gamma‐Poisson relationship, this paper investigates optimal allocation strategies of minimal repairs for parallel and series systems through implementing stochastic comparisons of various allocation policies in terms of the hazard rate, the reversed hazard rate, and the likelihood ratio orderings. Numerical examples are presented to illustrate these findings as well. These results not only strengthen and generalize some known ones in the seminal work of Shaked and Shanthikumar, but also solve the open problems proposed by Chahkandi et al.'s study and Arriaza et al.'s study.     

感应式磁性天线设计及干扰抑制算法研究

当期望信号和干扰同方向时,为了有效改善超低频频段的通信质量,提出了一种基于模拟电路预处理和改进广义旁瓣抵消的干扰抑制算法,设计了磁性天线、低噪声前置放大电路,制作了灵敏度较高的磁传感器,有效地抑制了工频及其谐波干扰。鉴于超低频频段的信号十分微弱,在广义旁瓣抵消算法的基础上做了几点改进,为主通道提供较多的参考信息,从而提高了算法的性能,有效地解决了传统算法失效的问题。为了验证所提算法的有效性,在实验室环境下搭建实验平台,设计了多组对照实验,实验结果表明:无论期望信号与干扰是否同方向,改进后的广义旁瓣抵消算法相比原来的算法,在信噪比的提升和噪声底限的降低等方面均有较大程度的改善。