一种基于模拟退火算法的雷达杂波仿真方法

分析了目前常用的杂波建模方法,阐述了最大熵分布的重要作用,提出了一种杂波幅度的统计建模方法,通过提取实测杂波数据的中心矩来对杂波幅度的随机特性进行描述,并通过模拟退火算法对杂波数据进行仿真。最后利用McMaster大学IPIX雷达的一组实测海杂波数据对算法进行了验证,结果表明,仿真数据与实测数据的最大熵分布具有很高的拟合程度。     

Allocation of two redundancies in two‐component series systems

The allocation of redundancies in a system to optimize the reliability of system performance is an interesting problem in reliability engineering and system security. In this article, we focus on the optimal allocation of two exponentially distributed active (standby) redundancies in a two‐component series system using the tool of stochastic ordering. For the case of active redundancy, stochastic comparisons are carried out in terms of the likelihood ratio and reversed hazard rate orders. For the case of standby redundancy, a likelihood ratio ordering result is developed. The results established here generalize and strengthen corresponding results in the recent literature. In addition, several numerical examples are used to explicate the results. © 2013 Wiley Periodicals, Inc. Naval Research Logistics, 2013     

综合火力／飞行控制系统空对空射击模态的半物理仿真研究

采用半实物仿真方法研究了综合火力／飞行控制系统的动态特性、作战有效性和工程实现的可行性。文中给出了系统的数学模型、系统的硬件结构和仿真试验结果。结果表明,综合火力／飞行控制系统可以减少瞄准过程时间,增加可射击时间,提高瞄准精度和系统稳定性,扩大攻击范围（全向攻击）,减轻飞行员工作负担,提高载机生存力。因而是很有发展前途的一种航空火力控制新概念。实验也表明工程实现是可能的。     

基于MATLAB/GUI的MIMO通信仿真软件设计与实现

为满足采用不同调制方式和空时编码类型的MIMO(Multiple Input Multiple Output)通信的性能分析需求,在深入研究MIMO通信机理和空时编译码机理基础上,基于MATLAB/GUI软件环境进行MIMO通信仿真软件设计,实现了对不同参数条件下MIMO通信系统性能分析的可视化、可交互性。仿真结果表明DBLAST(Diagonal Bell-Labs Layered Space-Time)在4FSK(Frequency Shift Keying)和QPSK(Quadrature Phase Shift Keying)调制方式下性能较优,利用设计的仿真软件可对MIMO通信的参数优化配置提供指导。     

Estimating distribution functions from partially observed samples

Suppose that some components are initially operated in a certain condition and then switched to operating in a different condition. Working hours of the components in condition 1 and condition 2 are respectively observed. Of interest is the lifetime distribution F of the component in the second condition only, i.e., the distribution without the prior exposure to the first condition. In this paper, we propose a method to transform the lifetime obtained in condition 1 to an equivalent lifetime in condition 2 and then use the transformed data to estimate F. Both parametric and nonparametric approaches each with complete and censored data are discussed. Numerical studies are presented to investigate the performance of the method. © 2000 John Wiley & Sons, Inc. Naval Research Logistics 47: 521–530, 2000     

基于状态的装备可靠度模型及其应用

为应用基于状态的装备可靠度模型,实现对装备的精确维修,采用了比例风险模型（Proportional Hazards Model,PHM）将装备的年龄信息及检测所得状态信息融入系统的风险函数中。考虑到样本包含截尾数据的情形,应用极大似然估计方法对模型中的参数进行了估计以及相应的模型检验。通过对该方法在一个实际案例中应用的详细分析,验证了方法的可行性。     

Analysis of down times of jib cranes—A stochastic approach

In this paper a case study dealing with the maintenance problem of jib cranes is presented. A jib crane is viewed as a complex system whose performance is observed as a single realization over period of time. After pointing out limitations of existing stochastic models to analyze the observed realization a new family of bivariate stochastic processes is introduced. The data of jib crane is analyzed using new model and cross‐validated using part of the data set. It is noted that the new family of stochastic processes is useful to analyze bivariate data where one of the variables is finitely valued and the other is nonnegative and continuous. © 2002 Wiley Periodicals, Inc. Naval Research Logistics 49: 231–243, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/nav.10006     

基因短序列模式分析及其在5'剪接位点识别中的应用

短序列模式分析是基因序列分析的一个重要组成部分,在进行生物信号识别的时候,一般都会利用到短序列模式的信息。通常短序列模式的数目很多,如果每个都应用到生物信号识别中,会产生大量的参数,而且无法体现信号的主要特征。为了找出在识别信号位点中起关键作用的短序列模式,以信息增益作为评价依据,按照逐步选择的策略,将模式进行排队。根据排队结果,选取信息增益突出的短序列模式作为识别生物信号的关键依据,这样可以用较少的模式得到较好的结果。结合选取的短序列模式,用最大熵模型作为信号序列真实分布的估计,从而对给定序列进行识别。最后将这个方法用于5’剪接位点的识别,得到了满意的结果。     

长码直扩信号的符号速率盲估计方法

针对长码直接序列扩频(DSSS)信号的符号速率估计的难题,提出了基于相关处理的方法。该方法首先估计长码直扩信号的相关函数二阶矩,然后将相关函数二阶矩的估计作为输入信号进行预处理,以去除扩频码周期处的峰值。对预处理后的信号再次进行自相关处理,则所得的信号的频谱中含有符号速率谱线。理论分析和计算机仿真证明了所提出的算法的有效性。     

基于相关熵的MACH滤波器

最大平均相关高度(MACH:Maximum Average Correlation Height)滤波器是一种重要的基于相关的模式识别方法。滤波器由训练数据线性构造而成,具有良好的畸变容忍能力,在线性高斯噪声条件下具有理论最优性。为将算法适用于广泛的非线性、非高斯情形,本文引入一种新的度量函数相关熵,可隐性地将输入数据通过非线性变换映射到特征空间;并在新的空间中提出了基于相关熵的MACH滤波器构造方法。最后将此方法应用于合成孔径雷达(SAR:Synthetic Aperture Radar)图像目标分类进行了实验,在接收机工作性能曲线和峰值旁瓣比的比对中,本文算法的性能均有所提升。