CDMA移动通信信号恒模特性的阵列有源校正算法

基于CDMA通信信号的恒模特性,提出了一种CDMA移动通信中的天线阵通道误差的有源在线校正算法。在天线阵列附近,发射扩谱序列正交于用户信号的同频辅助信号,用辅助信号对阵列接收信号解扩,采用恒模算法自适应的调节阵列通道滤波器参数,达到补偿阵列误差的目的。该方法克服了常规自校正算法受多径效应的影响和难以收敛不足。计算机模拟证实了该方法的有效性。     

欧拉角及欧拉运动学方程的MCAI

欧拉角与欧拉运动学方程是刚体力学中的教学难点之一 ,我们开发了刚体力学MCAI课件 ,并进行了教学实践。证明在刚体力学中采用MCAI课件教学是十分有益的     

On an Asymptotic Theory of Conditional and Unconditional Coverage Probabilities of Empirical Bayes Confidence Intervals

Empirical Bayes (EB) methodology is now widely used in statistics. However, construction of EB confidence intervals is still very limited. Following Cox (1975 ), Hill (1990 ) and Carlin & Gelfand (1990 , 1991 ), we consider EB confidence intervals, which are adjusted so that the actual coverage probabilities asymptotically meet the target coverage probabilities up to the second order. We consider both unconditional and conditional coverage, conditioning being done with respect to an ancillary statistic.     

The Use of Replicates in Logistic Measurement Error Modelling

The use of replicates is essential in logistic measurement error models with random, additive error, as it gives a consistent estimate of the variance of the measurement error. In this paper, we investigate two different aspects of the use of replicates. We look into the efficiency gain in using more than two replicates in situations where the replicates are correlated. We find that, unlike the situation with independent replicates, the efficiency gain is an almost linear function of the number of replicates. Further, we study the allocation of replicates among study subjects, and find that the optimal way of doing this is to allocate few replicates to as many subjects as possible, rather than allocating many replicates to fewer subjects.     

OpenCV耦合改进张正友算法的相机标定算法

视觉系统中的相机,由于透镜本身原因,采集到的图像往往会发生一定的畸变,从而影响后期的图像处理精度。 当镜头与图像平面夹角过小,或者标定图像次数过少时,普通标定算法往往存在标定不准,效果不佳等问题。对此,文中 提出了开源计算机视觉库( Open Source Computer Vision Librarv,OpenCV)耦合改进张正友标定算法的的相机定位机制。 首先研究了发生畸变的原因;再对普通张正友算法进行改进,随后通过OpenCV,计算出相机内参数、畸变系数、偏移向量 和旋转向量;最后结合改进后的张正有算法和OpenCV函数编程实现相机标定机制。实验结果显示：与未改进的张正友 标定算法相比,在镜头与图像平面夹角过小,或者标定图像次数过少时,文中机制具有更好的标定效果,在实际工程中具 有较大的应     

Optimal designs for calibration of orientations

This paper concerns designed experiments involving observations of orientations following the models of Prentice (1989) and Rivest &Chang (2006). The authors state minimal conditions on the designs for consistent least squares estimation of the matrix parameters in these models. The conditions are expressed in terms of the axes and rotation angles of the design orientations. The authors show that designs satisfying U₁ + … + U_n = 0 are optimal in the sense of minimizing the estimation error average angular distance. The authors give constructions of optimal n‐point designs when n ≥ 4 and they compare the performance of several designs through approximations and simulation.     

卫星通信用四波束有源相控阵方案

针对人们对大容量移动通信的要求,提出了一个地球静止通信卫星用的毫米波四波束直接辐射有源相控阵方案。通过选择商品化的元器件,并立足于国内工艺条件,得到的方案有721个单元,单元间距3倍波长。设计最大增益47dB,输出功率约140W,噪声系数小于4.5dB。     

LRL校准法及其在微波测量中的应用

讨论了微波器件的测量问题，阐明了ＬＲＬ（Ｌｉｎｅ－Ｒｅｆｌｅｃｔ－Ｌｉｎｅ）校准法的物理模型。应用微波网络理论建立了基本方程，运用矩阵方法推导出待测件散射参量的闭定式表达式。由于利用代数消去法，去除了嵌入参量相位不确定性引入的误差，ＬＲＬ法可用于微波晶体管测试夹具的去嵌入。     

柱状曲面容器内粒子图像测速中径向畸变校正方法

针对粒子图像测速（PIV）中速度矢量由于折射率引起的光学畸变进行了系统校正研究，提出了一种用于柱状曲面容器内PIV测量的径向光学畸变校正方法。并应用于泰勒一库埃特流测量的校正。     

Measurement errors in continuous-time capture–recapture models

The extent of bias due to measurement errors is an important problem in the context of regression and survival analysis. While research in these areas has been extensive and fruitful, investigations into the effect of measurement errors in capture–recapture models have been very limited. The contributions of this paper are to understand the effects of measurement errors in continuous-time capture–recapture models and to propose new methods to circumvent their impact. We derive asymptotic variance formulas for each method and assess their finite sample properties via simulation studies.