Transmit Diversity Schemes for WCDMA

Previous work on transmitter antenna diversity has shown that the use of multiple transmitter antennas at the base station results in improved performance due to increase of diversity (path diversity). This happens with no bandwidth cost, even when the signal quality along several paths is poor, but the receiver estimates the channel with accuracy. This paper evaluates the effects of channel estimation errors in the performance of the schemes designated as Space-Time Transmitter Diversity (STTD) and Selective Transmitter Diversity (STD). We consider low to medium signal to noise ratios characteristic of Wideband Code Division Multiple Access (WCDMA) networks. Different fading channel models are considered for comparison between the two schemes. The improvement due to convolutional coding associated with these techniques is also evaluated.     

Provision of accuracy for quantitative determination of small amounts of components: Principles of resolving the problem and their realization

Versions are suggested for resolving the problem of monitoring the accuracy of determining small amounts of components in samples of substances and materials. __________ Translated from Izmeritel'naya Tekhnika, No. 1, pp. 52–57, January, 2006.     

Assumptions and Consequences of Treating Providers in Therapy Studies as Fixed Versus Random Effects: Reply to Crits-Christoph, Tu, and Gallop (2003) and Serlin, Wampold, and Levin (2003).

In their comments on the authors' article (see record 2003-10163-009), R. C. Serlin, B. E. Wampold, and J. R. Levin (see record 2003-10163-011) and P. Crits-Christoph, X. Tu, and R. Gallop (see record 2003-10163-010) took issue with the authors' suggestion to evaluate therapy studies with nested providers with a fixed model approach. In this rejoinder, the authors' comment on Serlin et al's critique by showing that their arguments do not apply, are based on misconceptions about the purpose and nature of statistical inference, or are based on flawed reasoning. The authors also comment on Crits-Christoph et al's critique by showing that the proposed approach is very similar to, but less inclusive than, their own suggestion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

影响GPS水准高程的因素及高程拟合方法的探讨

在简单介绍高程系统的基础上，对影响GPS高程精度的几何水准联测误差、卫星分布不对称、星历误差、多路径误差等因素逐一进行了分析，并提出了相应的改进措施。同时，还对高程拟合使用的稳健估计方法进行了探讨。     

摩托车起动电机安装设计及工艺保证

介绍摩托车起动电机的安装设计原则和方法，安装误差的形成与计算，以及达到安装设计要求的工艺保证措施，同时还分析了在检测和加工中所存在的一些做法。     

Asymptotic efficiency properties of least squares in an ultrastructural model

This paper considers the estimation of both the intercept term and the slope parameter in a linear ultrastructural model using direct regression and reverse regression methods. Without assuming the errors to be normally distributed, asymptotic expressions for the bias and the variance of the estimators are derived and analyzed. The effect of departure of the errors from normality is also studied.     

GJK-3型高准确度长度测量仪

本文分析了使用计数的原理来测量长度、转速的仪器，其误差产生的原因，并结合G3K-3型高准确度长度测量仪，着重介绍了消除误差的方法．     

虚拟红外成像器件的模拟输出电路设计

虚拟红外成像器件是能输出红外图像数据源的器件,在调试图像采集系统的硬件和软件时能替代非制冷红外焦平面阵列。虚拟成像器件的输出具有很好的线性度和精度,可作为图像采集电路的标定器件。文设计了虚拟红外成像器件的模拟输出电路,根据UL03401性能参数,设计了信号调理电路,通过在FPGA上使用ROM中查表方式校正模拟端口输出误差,在实际应用中表现了良好的精确性。     

基于小波多尺度分析的光纤陀螺振动误差分析与建模

针对振动环境对光纤陀螺性能的影响,对某型号的光纤陀螺进行了线振动实验并对实验结果进行了Allan方差分析。利用小波多尺度变换提取了光纤陀螺误差模型中的各误差项,分析并验证了零漂及噪声误差与Allan方差分析误差系数中的量化噪声、角度随机游走以及零偏误差与误差系数中的零偏稳定性、速率随机游走、速率斜坡之间的对应关系。随后利用RBF神经网络对小波多尺度分析提取的零偏误差建立模型并进行了补偿。仿真结果表明,本文提出的方法有效减小了振动环境下各误差项对光纤陀螺性能的影响, Allan方差分析结果中的五个误差系数均有较大下降,其中两项误差系数下降了一个数量级及以上,极大提高了光纤陀螺在振动环境下的输出精度,对光纤陀螺在振动环境下的误差研究具有重要指导意义。