基于自适应修正曼哈顿距离的室内定位方法

在室内WiFi环境下,针对常见指纹匹配算法所忽略的信号波动问题,提出了一种基于自适应修正曼哈顿距离和AP选择的指纹匹配算法,并结合加权K近邻方法实现定位。首先采用AP选择算法获取部分受干扰程度小和出现频率高的AP,在指纹匹配时仅使用该部分AP的接收信号强度进行计算;在分析WiFi信号传播衰减公式和信号波动的基础上,提出了将自适应修正曼哈顿距离作为指纹匹配的度量距离,使用该距离旨在平滑信号波动对指纹相似度计算的影响;最后采用加权K近邻方法估计测试点的坐标。实验结果表明,在加权K近邻方法的框架下,基于自适应修正曼哈顿距离的定位算法在定位精度上优于基于欧氏距离、曼哈顿距离、余弦距离和Sorensen距离的定位算法。     

基于耦合场压电分析的失谐叶盘振动仿真模拟

针对典型失谐叶盘结构振动响应局部化实验需求,通过有限元仿真验证实验的最坏叶片失谐模式,基于ANSYS软件的直接耦合场压电分析功能,对粘贴在叶片根部的各压电陶瓷片施加行波谐激励电压,模拟了失谐叶盘的振动响应局部化特性。数值仿真结果与实验结果得到了良好的验证,为进行失谐叶盘振动局部化实验研究提供了有效的支撑。     

基于振型节径谱的失谐叶盘结构动态特性评价

基于叶盘结构振型的离散傅里叶变换,给出振型节径谱的定义。对于一个简化的叶盘结构,利用节径谱的概念对失谐叶盘的动态特性进行了评价和分析。在固有特性方面,基于节径谱改进了模态局部化因子的定义,得到了随机失谐叶盘的模态特性的统计特征;在响应特性方面,基于振型和激励节径谱的相似程度定义了模态激励因子,很好地解释了随机失谐程度的＂阈值＂效应和最优人为失谐的存在性。算例表明,节径谱是衡量的振型空间分布的重要指标,在失谐叶盘结构动态特性分析和评价中有着重要的应用。     

直升机复合材料国产化桨叶剖面特性的分析

由于国产复合材料性能较进口复合材料有较大变化,根据替代前后桨叶的动力学特性基本不变的原则对原桨叶结构进行了调整。采用薄壁梁横截面剪流相等的原理推导了桨叶扭转刚度的计算公式,基于挥舞刚度、摆振刚度、质量分布的定义得到了迭代公式。对某直升机替代前后桨叶的剖面特性进行了计算。结果表明：替代前后桨叶的扭转刚度、挥舞刚度、摆振刚度及单位长度质量分布完全一致,说明替代前后桨叶的剖面特性有很好的一致性。     

一种单星仅测TOA无源定位方法

因单星测向定位体制存在系统构成复杂、对卫星载荷和姿态要求高等问题,提出 一种单个低轨卫星仅测脉冲到达时间（TOA）实现对地表静止辐射源无源定位的方法。在研 究仅测脉冲TOA估计径向加速度的基础上,提出采用网格搜索法进行定位的方法。推导得到 了该方法定位误差的克拉美-罗下限（CRLB）及对于不同位置辐射源的定位误差几何分布（G DOP）,并分析了该方法的可实现性。理论和仿真分析表明,该方法实现简单,适用范围广 ,定位性能满足实际需求。
     

基于能量沉淀分布的Polar自主定位方法

本文通过对polar自主定位方法的研究,发展了基于gamma射线源在polar塑料闪烁体能量沉淀分布的定位方法,开展了polar自主定位方法的模拟试验验证,分析了polar自主定位可能的影响因素,提出了polar自主定位对电子学系统的设计要求和建议。该研究课题在没有专门定向仪器的情况下,仅采用polar基于Geant4模拟粗略分辨出gamma射线源从哪一个方向入射,分析其显著性。课题成果将应用于polar偏振探测器对gamma射线源的定位,同时可为评估polar电子学系统提供测试依据。     

基于GAS的图像跟踪系统及其实现方案

利用遗传优化算法实现了一个目标跟踪系统,将传统的目标搜索、目标分割、目标定位及跟踪状态评估等过程都由遗传算法来实现,使系统结构简单,易于实现。并分析了利用 TMS32 0 C6x实时实现遗传优化跟踪过程的可能性,最后给出了该系统的实现方案     

基于Gabor滤波器的图像目标识别方法

为了给机器人视觉导航提供有效信息,提出一种基于图像匹配的目标识别方法.对CCD采集的目标图像,由 Gabor 变换生成的二维Gabor 滤波器有着优良的滤波器性能,不需要对图像进行分割,能适应一定的旋转、尺度、光照的变化,通过多个频率和角度的Gabor算子与图像的卷积,获取图像全局信息的特征描述.分类方法采用统计学习理论基础上发展起来的一种新的机器学习方法——支持向量机(SVM, Support Vector Machines),它可解决模型选择、过学习、维数灾难等问题.通过支持向量机进行多维特征向量的分类.该方法可达到较高的识别率,达到实时处理的要求,可以在人脸识别、机器人视觉定位等领域得到应用.      

基于PSO的多观测器轨迹优化研究

在多观测站目标被动跟踪过程中,多观测器运动轨迹对定位跟踪精度有重要影响.为提高对运动目标的跟踪精度,将目标滤波协方差的迹作为目标优化函数,提出一种基于粒子群算法(Particle Swarm Optimi-zation,PSO)的多观测器轨迹优化方法,并将轨迹优化加入运动目标被动跟踪过程中,实现了观测器自适应运动下的运...     

Plants + soil/wetland microbes: Food crop systems that also clean air and water

The limitations that will govern bioregenerative life support applications in space, especially volume and weight, make multi-purpose systems advantageous. This paper outlines two systems which utilize plants and associated microbial communities of root or growth medium to both produce food crops and clean air and water. Underlying these approaches are the large numbers and metabolic diversity of microbes associated with roots and found in either soil or other suitable growth media. Biogeochemical cycles have microbial links and the ability of microbes to metabolize virtually all trace gases, whether of technogenic or biogenic origin, has long been established. Wetland plants and the rootzone microbes of wetland soils/media also been extensively researched for their ability to purify wastewaters of a great number of potential water pollutants, from nutrients like N and P, to heavy metals and a range of complex industrial pollutants. There is a growing body of research on the ability of higher plants to purify air and water. Associated benefits of these approaches is that by utilizing natural ecological processes, the cleansing of air and water can be done with little or no energy inputs. Soil and rootzone microorganisms respond to changing pollutant types by an increase of the types of organisms with the capacity to use these compounds. Thus living systems have an adaptive capacity as long as the starting populations are sufficiently diverse. Tightly sealed environments, from office buildings to spacecraft, can have hundreds or even thousands of potential air pollutants, depending on the materials and equipment enclosed. Human waste products carry a plethora of microbes which are readily used in the process of converting its organic load to forms that can be utilized by green plants. Having endogenous means of responding to changing air and water quality conditions represents safety factors as these systems operate without the need for human intervention. We review this research and the ability of systems using these mechanisms to also produce food or other useful crops. Concerns about possible pathogens in soils and wastewater are discussed along with some methods to prevent contact, disease transmission and to pre-screen and decrease risks. The psychological benefits of having systems utilizing green plants are becoming more widely recognized. Some recent applications extending the benefits of plants and microbes to solve new environmental problems are presented. For space applications, we discuss the use of in situ space resources and ways of making these systems compact and light-weight.