机动目标一维距离像RAT法线性化补偿

研究了机动目标宽带线性调频脉冲回波全去斜率信号模型,根据速度和加速度的调频频谱展宽特点,提出了机动目标宽带一维距离像线性化调频回波模型,给出了Radon模糊图转换(RAT)法线性参数估计与运动补偿方法,并进一步分析了测速和测距误差.仿真实验验证了RAT法一维距离像线性化参数估计与补偿,表明该方法很好地解决了运动参数未知情况下机动目标的一维距离像频谱展宽问题.     

基于先验知识的降秩STAP方法研究

提出了一种基于杂波先验知识的降秩(RR)空时自适应处理(STAP)方法——KA-RR法,该方法首先利用载机平台运动参数、雷达系统参数及地形、地貌参数等先验知识构建机载雷达杂波模型,然后通过该模型对机载雷达杂波数据进行预白化处理,最后利用降秩STAP方法自适应抑制剩余杂波。仿真结果表明,相对于传统的降秩STAP方法,KA-RR方法具有更好的杂波抑制性能和更强的鲁棒性。     

FMEA与粗糙集相结合的故障预测方法

基于FMEA和粗糙集决策系统基本理论,对飞机中分系统故障预测问题进行了研究。首先定义故障预测所需的征兆并对系统进行FMEA,按照FMEA分析结果分次向系统模型注入引起特定故障的事件,采集含有故障趋势的系统模型的信息用于构建适用于故障预测的粗糙集决策表,对该表进行了处理,最终发现用于故障预测的知识(即决策规则和算法);最后运用所发现的知识进行故障预测。     

A general model of heterogeneous system lifetimes and conditions for system burn‐in

Burn‐in is a technique to enhance reliability by eliminating weak items from a population of items having heterogeneous lifetimes. System burn‐in can improve system reliability, but the conditions for system burn‐in to be performed after component burn‐in remain a little understood mathematical challenge. To derive such conditions, we first introduce a general model of heterogeneous system lifetimes, in which the component burn‐in information and assembly problems are related to the prediction of system burn‐in. Many existing system burn‐in models become special cases and two important results are identified. First, heterogeneous system lifetimes can be understood naturally as a consequence of heterogeneous component lifetimes and heterogeneous assembly quality. Second, system burn‐in is effective if assembly quality variation in the components and connections which are arranged in series is greater than a threshold, where the threshold depends on the system structure and component failure rates. © 2003 Wiley Periodicals, Inc. Naval Research Logistics 50: 364–380, 2003.     

Transformation of Military Ethics During the Zhou Dynasty in Ancient China

ABSTRACT

The transformation of the governance model from a rule of virtue to political realism in China has been a topic of great interest to scholars. In this study, I examine military culture during the Zhou Dynasty and investigate the changes in ethics based on factors such as cultural values, social customs, and political structure to understand the process by which moral values have changed as the governance model transformed from rule of virtue to political realism. I found that military ethics have changed from governance through the use of rituals during the Western Zhou Dynasty to what was called “deception makes an army” during the Eastern Zhou Dynasty.     

Empirical Biases and Some Remedies in Estimating the Effects of Selective Reenlistment Bonuses on Reenlistment Rates

Researchers have, for decades, been attempting to estimate the effects of Selective Reenlistment Bonuses (SRBs) on the probability of reenlistment for the military services. SRBs are targeted to specific military occupations for which reenlistment rates are lower (or expected to be lower) than what is needed. This article first identifies four primary sources of biases affecting these models: reverse causality from supply shifts (a negative bias), the endogeneity of the decision point causing coded SRBs to be higher for reenlisters than leavers (a positive bias), measurement error (a likely negative bias), and excess supply preventing the full effect of an SRB change to materialize (a positive or negative bias). The report proceeds to develop a model that attempts to address the first two biases. With U.S. Navy data from FY2001-FY2008, I examine the extent to which these two biases are affecting the estimated SRB effects. Despite these corrections, the difficulty of addressing the other biases calls into doubt studies that examine the effects of retention bonuses or even the effects of the structure of military pay in general.     

内置频率对Duffing振子微弱二进制相移键控信号盲检测影响

采用Duffing振子实现对微弱二进制相移键控（Binary Phase Shift Keying, BPSK）信号的盲检测时，Duffing系统输出的周期态和混沌态转换之间存在过渡带。针对这一问题，推导出过渡带时长和Duffing系统内置频率之间的关系表达式；指出内置频率越高，过渡带时间越短；仿真实验给出时间频率响应曲线。内置频率的提高，会降低系统检测微弱信号的灵敏度。针对这一问题，推导出周期态下Duffing系统输出幅度作为因变量、内置频率作为自变量的表达式；仿真实验给出幅频响应曲线。针对微弱BPSK信号盲检测，建立变尺度方法和检测阵列相结合的基于S变换提取Duffing系统输出幅度包络的微弱BPSK信号盲检测模型，仿真实验验证了模型方法的有效性。     

HLA和视景仿真技术的装甲车辆乘员协同训练系统

简单介绍了HLA/RTI的特点和功能,讨论了利用MultiGen Creator 和 Vega Prime建立三维模型时用到的关键技术,以及部分特效的实现技巧.并详细说明了分布式协同训练系统下的时间管理和数据分发管理的实现策略.给出了基于HLA/RTI和三维视景仿真技术下分布式协同训练系统的实现方法.     

运动目标轨迹分类与识别

运动目标轨迹识别是运动分析中的基本问题,其目的是解释所监视场景中发生的事件,对所监视场景中运动目标轨迹的行为模式进行分析与识别,智能地做出自动分类.对轨迹有效性判断后采用K均值聚类,引入改进的隐马尔可夫模型算法,针对轨迹的复杂程度对各个轨迹模式类建立相应的隐马尔可夫模型,利用训练样本训练模型得到可靠的模型参数,计算测试样本对于各个模型的最大似然概率,选取最大概率值对应的轨迹模式类作为轨迹识别的结果,对两种场景中聚类后的轨迹进行训练与识别,平均识别率较高,实验结果表明该方法是有效的.     

SiC纤维表面CVD SiC涂层对其单丝强度的影响

采用化学气相沉积(CVD, Chemical Vapor Deposition)工艺在KD-I型SiC纤维表面制备了SiC涂层,选择2h、4h、6h和8h四个时间点研究了沉积时间对纤维性能的影响.结果表明:具有CVD SiC涂层的SiC纤维较无涂层的纤维来说强度有所下降;在所研究的沉积时间范围内,随着沉积时间的增加,涂层的厚度有所增加,涂层由不连续的岛状转变为连续层状,纤维的单丝强度出现了先升后降的趋势.