基于互相关定位法的干涉仪分析与仿真

首次提出用时域互相关法处理Sagnac/Mach-Zehnder分布式光纤传感系统的干涉输出信号, 对扰动进行检测和定位。首先对Sagnac/Mach-Zehnder分布式光纤传感系统进行了扰动检测和定位的理论分析, 推导出扰动引起的干涉输出信号的表达式, 利用Bessel函数展开, 确定了该系统的两路干涉输出满足时域互相关的特性。在此基础上进一步分析了两路干涉信号的表达式, 提出基频定位法和微分定位法两种时域互相关方法处理干涉信号, 确定扰动位置。对两种扰动定位方法进行了Matlab仿真, 并通过实验在多个扰动位置多次验证了两种方法的正确性。     

一种利用历史数据构造虚拟标签的定位算法

在RFID定位算法中,利用接收信号强度统计模型进行直接定位的精确度不高,而利用实际参考标签定位存在信号易碰撞、外出部署不便等问题,因此提出一种基于虚拟标签的RFID定位算法VIREH以克服以上缺点.该算法利用历史数据构建虚拟参考标签,然后利用虚拟参考标签代替实际参考标签进行定位.依据VIREH算法,开发基于Android移动设备的RFID定位系统,在系统中使用VIREH算法进行定位,对定位误差进行了统计以测试算法性能.测试结果表明,VIREH算法的定位精度较直接定位有显著提高,较使用实际参考标签没有明显降低,有助于提高RFID定位精度.     

Orientation ofMicroplitis croceipes (Hymenoptera: Braconidae) to green leaf volatiles: Dose-response curves

FemaleMicroplitis croceipes wasps were tested in a wind tunnel for their ability to orient to various concentrations of eight different green leaf volatile (GLV) substances [hexanal, (E)-2-hexenal, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, (E)-2-hexenyl acetate, (Z)-3-hexenyl acetate, (Z)-3-hexenyl propionate, and (Z)-3-hexenyl butyrate]. Overall, the esters elicited the greatest percentage of successful orientation flights, the alcohols elicited an intermediate response, and the aldehydes elicited a low response. The semilog dose-response curves were generally hill-shaped with high responses at medium release rates and low responses at high or low release rates. For the aldehydes, positive responses occurred at all GLV release rates between 0.01 and 100 nl/min. For some alcohols and esters, positive responses occurred at release rates as low as 1 pl/min and as high as 1μl/min. These data show thatM. croceipes wasps are strongly attracted to GLVs and are capable of orienting to GLV concentrations that would occur in nature when a caterpillar feeds on a green leaf. Hence, in nature, GLVs may be important clues, enablingM. croceipes to locate their hosts.     

基于扰动测度的电能质量扰动源定位方法

针对现有电能质量扰动源定位方法中对扰动方向表征不足的问题,引入扰动测度概念,测量扰动的大小和方向,提出一种扰动方向的定量表示方法以及相应的扰动源定位算法。首先利用基本信度分配函数对扰动方向进行量化处理,然后通过隶属度函数对扰动功率和扰动能量进行综合定位,得出多测点的扰动方向测度列向量,结合覆盖矩阵得出最终的定位结果.仿真结果表明：在原方法定位不准确的情况下,新方法仍然能够正确定位扰动源,证实了此方法的有效性和可行性.     

基于MVEKF的测向交叉定位跟踪算法

测向交叉定位能够根据两个或多个测量站对同一目标辐射源测得的方位信息,采用最佳状态估计法确定出目标辐射源的位置．针对扩展卡尔曼滤波（EKF）算法存在受初值、测量噪声影响大等缺点,将一种新的修正协方差的扩展卡尔曼滤波（MVEKF）算法应用到固定双站测向交叉定位中,可以提高收敛速度和定位精度．通过与EKF的仿真对比,验证了该算法具有更好的跟踪性能．     

基于蚁群算法的离散救援问题出救点选址研究

为解决应急物流中的出救点选址问题,建立了相应数学模型,引入蚁群算法解决问题。多数应急物流可以归为点对点的支援问题,出救点的设置应该在保证出救有效的条件下使出救点最少、救援时间最短,属于双层规划问题。双层规划问题是NP难题,可以应用蚁群算法解决。出救点选址问题在蚁群算法中可以视为蚁群的聚类,通过对信息素衰减及相邻蚂蚁的吸引作为启发因子,可以得到蚁群的聚类效果。实验结果表明,基于蚁群算法的选址问题解决方案能获得理想的选址效果,收敛速度较快。     

3-cactus上的连通p-median问题

设G=(V,E)是一个无向连通图,每一条边e和每个顶点v都有一个非负的权重l(e)和w(v);传统的p-median是指在顶点集合中选出p个顶点,使得其它顶点到这p个顶点的赋权距离和最小。该文考虑带有某些约束的这类问题,要求所选出的p个顶点是连通的,也即由这p个顶点所导出的子图是连通的,称为连通p-median问题。该文给出了3-cactus图上的连通p-median问题的一个O(pn)的算法。     

战略资源整合与IT企业对外投资区位选择

近几年我国的IT企业发展迅速。该文基于战略资源整合理论,从动态的角度对IT企业对外投资的区位选择进行分析。将企业对外投资的区位选择与企业自身所具有的战略资源、投资动机结合起来分析,建立区位优势评价模型,通过主客观赋权法得出区位优势评价模型中各指标折权重,并以中兴通讯有限公司为例进行实证分析,根据分析得出结论并对我国IT企业对外投资的区位选择提出建议。     

三站匀扫波束时差定位及测量误差

该文针对仅由时差测量所得到的波束扫描角,并利用平面三角函数关系,即能直接在极坐标系中导出非直线不等间距三站阵列对匀速扫描雷达站的定位公式。应用误差估计理论所做的分析显示,基于匀速波束扫描时差测量的三站无源定位系统具有较高的测向精度,且在基线方向不存有测向盲区。采用非直线、不等距布阵亦能进一步有效降低测向误差。如V形布阵,则在阵列夹角的中心线上具有最小误差值。同时,误差分析亦表明,目前所给出的距离公式的测量误差还是较大的。     

Optimum location of surface wells for remote pressure relief coalbed methane drainage in mining areas

Based on engineering tests in the Huainan coal mining area,we studied alternative well location to improve the performance of surface wells for remote pressure relief of coalbed methane in mining areas.The key factors,affecting location and well gas production were analyzed by simulation tests for similar material.The exploitation results indicate that wells located in various positions on panels could achieve relatively better gas production in regions with thin Cenozoic layers,low mining heights and slow rate of longwall advancement,but their periods of gas production lasted less than 230 days,as opposed to wells in regions with thick Cenozoic layers,greater mining heights and fast rates of Iongwall advancement.Wells near panel margins achieved relatively better gas production and lasted longer than centerline wells.The rules of development of mining fractures in strata over panels control gas production of surface wells.Mining fractures located in areas determined by lines of compaction and the effect of mining are well developed and can be maintained for long periods of time.Placing the well at the end of panels and on the updip return airway side of panels,determined by lines of compaction and the effect of mining,would result in surface wells for remote pressure relief CBM obtaining their longest gas production periods and highest cumulative gas production.