采用重构吸引子的辐射源个体识别技术

为解决现有基于相空间个体识别方法面临重构特征矢量维数高、计算效率低、鲁棒性差等问题,从非线性动力学角度出发,构建了基于重构吸引子的辐射源个体识别框架,并在此框架内提出了基于等距映射的辐射源个体识别技术。该技术采用等距映射从相空间中重构辐射源吸引子,可以更低的维度描述辐射源系统动力学特性,反映辐射源个体的“指纹”特征。实验表明该方法识别准确率更高、效率更高、听鲁棒性更强。     

Two novel critical shock models based on Markov renewal processes

In this paper, we investigate systems subject to random shocks that are classified into critical and noncritical categories, and develop two novel critical shock models. Classical extreme shock models and run shock models are special cases of our developed models. The system fails when the total number of critical shocks reaches a predetermined threshold, or when the system stays in an environment that induces critical shocks for a preset threshold time, corresponding to failure mechanisms of the developed two critical shock models respectively. Markov renewal processes are employed to capture the magnitude and interarrival time dependency of environment-induced shocks. Explicit formulas for systems under the two critical shock models are derived, including the reliability function, the mean time to failure and so on. Furthermore, the two critical shock models are extended to the random threshold case and the integrated case where formulas of the reliability indexes of the systems are provided. Finally, a case study of a lithium-ion battery system is conducted to illustrate the proposed models and the obtained results.     

使用平均周期进行指纹分类

提出了一种基于指纹平均周期的分类方法,通过计算指纹的平均周期并按照平均周期将数据库中的指纹进行排序,该方法可有效地提高指纹的搜索速度。若将基于指纹周期的分类算法和现有的指纹分类算法结合起来,则可进一步提高指纹搜索效率。     

二维周期钢管阵列带隙特性计算中的时域有限差分算法

通过选取合适的离散时间间隔,解决了大密度、弹性常数差界面上时域有限差分(FDTD)算法的不稳定现象。进而采用改进的O(2,4)精度FDTD算法,计算了由空气中二维周期钢管正方阵列组成的晶格常数为103mm的声子晶体的Г Х方向禁带,计算结果与测试结果吻合较好。     

Preservation of stochastic orders for random minima and maxima,with applications

It is shown, in this note, that the right spread order and the increasing convex order are both preserved under the taking of random maxima, and the total time on test transform order and the increasing concave order are preserved under the taking of random minima. Some inequalities and preservation properties in reliability and economics are given as applications. © 2003 Wiley Periodicals, Inc. Naval Research Logistics, 2004.     

潜在故障状态可测的一种故障检查模型

从系统的功能故障状态和潜在故障状态两方面讨论了故障检查模型,基于延迟时间模型推导了系统的期望可用度模型并对其适用性进行了讨论与验证。     

关于一食物链型时滞系统的注记

考虑了一个自治的有密度制约与扩散项的n种群食物链型时滞系统,得到了持续生存系统的充分条件,推广了前人持续生存的相应结果。     

Averaging frameworks for simulation optimization with applications to simulated annealing

We present two frameworks for designing random search methods for discrete simulation optimization. One of our frameworks is very broad (in that it includes many random search methods), whereas the other one considers a special class of random search methods called point‐based methods, that move iteratively between points within the feasible region. Our frameworks involve averaging, in that all decisions that require estimates of the objective function values at various feasible solutions are based on the averages of all observations collected at these solutions so far. Also, the methods are adaptive in that they can use information gathered in previous iterations to decide how simulation effort is expended in the current iteration. We show that the methods within our frameworks are almost surely globally convergent under mild conditions. Thus, the generality of our frameworks and associated convergence guarantees makes the frameworks useful to algorithm developers wishing to design efficient and rigorous procedures for simulation optimization. We also present two variants of the simulated annealing (SA) algorithm and provide their convergence analysis as example application of our point‐based framework. Finally, we provide numerical results that demonstrate the empirical effectiveness of averaging and adaptivity in the context of SA. © 2012 Wiley Periodicals, Inc. Naval Research Logistics, 2012     

基于粒子群聚类的导弹直接侧向力模型辨识

为了充分挖掘数据的潜在规律,提出一种基于粒子群模糊C均值聚类的模型辨识方法,该方法首先对实验数据进行分类,得到最佳聚类数和聚类中心,然后对不同的类分别辨识.新数据可以根据到不同聚类中心的距离划分为不同的类,再根据该类的辨识模型得到输出结果.依据风洞实验数据,采用粒子群模糊聚类对直接侧向力模型进行了辨识,辨识结果表明,与直接辨识相比,该方法的辨识精度明显提高,其辨识结果可以为控制系统的设计提供依据.     

基于PCB技术的延时线设计方法

为了设计大功率低损耗的延时线,提出了用多股窄印制线并行绕制替代单股印制线绕制、在某些特定位置将并绕的多股印制线交叉换位的多层PCB螺旋电感的设计方法,并用该电感和电容模拟电缆的分布参数电感和电容制作延时线。通过多股并绕交叉换位的方式可以增加电感的有效截面积,减小电感的涡流损耗,有效提高电感的品质因数。测试结果表明:该螺旋电感的品质因数在短波频段内有较大提高。利用该螺旋电感制作的200ns延时线在通1A电流50 W功率时,延时性能好、驻波比小、衰减量小,满足大功率低损耗的要求。