散斑调制用于提高体全息相关器的识别率

体全息相关器能够进行快速的光学并行相关识别．但是在相关识别的过程中，页间串扰导致相关结果中旁瓣太多，影响了相关峰的判断，大大降低了相关器的识别准确率。为了抑制旁瓣．对传统的体全息相关公式中所产生串扰的因子进行了分析，引入了随机函数的自相关函数作为调制因子对公式进行修正．可以实现在水平方向和竖直方向同时抑制旁瓣．抑制效果与全息图的厚度无关。并提出在相关器的物光光路中物的前方放置随机相位器，实现对物函数的散斑调制。理论分析、数值计算及实验结果表明．该方法可以抑制旁瓣．突出相关峰．提高体全息相关器的识别准确率和通道密度。     

钢筋混凝土柱爆破实验的灰关联分析

拆除爆炸中,如何设计好各种构件,如柱、梁的爆破,是建筑物能够倒塌解体的关键技术之一.在钢筋混凝土柱的爆破实验因素分析中引入新的分析方法--灰关联分析法.分析结果包含了设计主要参数与结果参数之间的各种变化关系,与关系曲线法分析结果作了对照,表明这种方法具有一定推广价值.     

基于CDMA技术的多水印算法

将码分多址（CDMA）思想引入水印系统以实现多水印方案。在水印嵌入过程中，每一用户以自己的密钥作为种子生成一个伪随机分布的地址码，并用该地址码将自己的欲嵌入信息调制为载波信号，然后以相加的方式把载波信号叠加入载体。在提取时，该用户使用相同的地址码，通过计算地址码和载体之间的相关系数，从载体中提取自己的嵌入信息。实验证明该算法可以实现多个用户独立嵌入和检测自己的水印信息，完全能满足多水印的要求。     

织物预成型体厚度方向渗透特性研究

以达西定律为基础,研究了不同类型织物的织物层数、定型剂质量分数以及铺层角度对织物预成型体厚度方向上渗透性能的影响.实验结果表明,在一定的定型剂质量分数下,测试流体在垂直方向上的流动基本为稳态流动,大体受Darcy定律控制.随着织物层数的增加,流体流速减小,预成型体厚度方向渗透率逐渐增加.随定型剂质量分数的增加,厚度方向渗透率表现出先增大而后又减小的趋势,而且织物的铺层角度对预成型织物厚度方向渗透率也具有较大影响.     

Hermite插值在车桥耦合振动中的应用

车桥耦合竖向振动分析中，轮对和与其接触的桥梁竖向位移相等，但振动速度、加速度并不相等，传统方法用轮对与桥梁接触点处桥梁振动速度和加速度代替轮对的振动速度、加速度。本文通过引进Hermite插值函数，推导出车辆以一定速度过桥时轮对竖向位移、振动速度和加速度理论值，并且轮对的竖向位移、振动速度和加速度可由轮对所在桥梁单元节点的竖向位移、振动速度和加速度求得，在有限元动力计算中易于实现。本文的算例表明在车辆低速过桥情况下，用轮对所在位置桥梁的振动速度、加速度来代替轮对的振动速度、加速度误差很小，但是车辆高速过桥时，计算结果误差较大。     

基于垂直扭转梳齿驱动结构的硅微机械扭转微镜的设计加工与表征

为了改善扭转微镜的机电耦合特性和光学特性，提出了一种新的基于SOI硅片的垂直扭转梳齿静电驱动结构．通过有限元与边界元方法，对不同厚度扭转梁的机电耦合特性进行了数值模拟，得到了相应的阈值电压和吸合电压，并提出了几种新的折叠梁结构，以进一步改善器件的机电耦合特性；通过力学分析，从理论上推导了垂直扭转梳齿静电驱动方式微镜的最大扭转角度、阈值电压、扭转刚度以及固有频率，获得了结构参数对器件机电耦合特性的影响机制；最后，利用比例散射理论讨论了表面粗糙度、入射光束波长和入射角度等参数对微镜表面光学反射性能的影响，并利用原子力显微镜测量了微镜的表面粗糙度，理论模拟与实验研究表明，基于SOI硅片和垂直扭转梳齿结构的硅微机械扭转微镜可显著降低器件的驱动电压，提高器件的机电耦合特性和微镜表面的光学反射特性．     

近年降膜式吸收器计算模型概述

介绍近十年来竖直管和平板降膜式吸收器计算模型的发展，以理论模型的改进过程为序，概括叙述各种模型所采用的假设、控制方程、边界条件和数学方法，通过计算结果探讨各种模型的优缺点，有利于进一步优化数学模型。     

DS／BPSK信号载频估计的互相关积累法

针对强高斯白噪声背景下的DS/BPSK信号载频估计问题,在研究平方倍频法的基础上,借鉴相关积累思想,提出了一种互相关积累法。该方法利用余弦信号相关而噪声不相关的特性,在平方倍频处理后端加入了互相关积累手段与集平均技术,改善了处理的输出信噪比。计算机仿真表明,两次接收分段互相关积累法在成功地实现了比传统估计方法更低的信噪比容限的同时还有效地节省了系统设备量。     

MIMO Channel Characterization for Short Range Fixed Wireless Propagation Environments

This paper reports results from wideband MIMO measurements performed in short range fixed wireless environments at 5.2 GHz. The objective is to provide MIMO channel characterization results for the measured environments and contribute to the limited available similar studies. Two kinds of propagation scenarios are investigated, rooftop to rooftop and street to rooftop, at three different sites always under LOS propagation conditions. The analysis of measurement data is performed in the context of non physical modeling, providing insight into the statistics of the measured channels. In particular, the slow time varying nature of the channel is studied and the narrow Doppler spectrum shape is approximated. Furthermore, frequency correlation results are obtained and the typical delay dispersion measures are extracted. Then, the antenna correlation is studied and the error of the Kronecker product approximation is evaluated. Finally, capacity results are provided and the channel measurements are characterized in terms of spatial multiplexing quality and multipath richness through condition number analysis. Nikolaos D. Skentos received his Diploma in Electrical and Computer Engineering from the National Technical University of Athens (NTUA), Greece in October 2000. Since January 2001 he has been a research associate at the Mobile Radio Communications Laboratory at the NTUA, and he is currently working towards the Ph.D. degree. His research interests include channel measurements, MIMO channel characterization, MIMO algorithms and space time processing. He has been active in the IST STINGRAY project, the COST 273 Action and the ACE Network of Excellence. He is also a member of the National Technical Chamber of Greece since 2001. Athanasios G. Kanatas received the Diploma in Electrical Engineering from the National Technical University of Athens, Greece, in 1991, the M.Sc. degree in Satellite Communication Engineering from the University of Surrey, Surrey, UK in 1992, and the Ph.D. degree in Mobile Satellite Communications from the National Technical University of Athens, Greece in February 1997. From 1993 to 1994 he was with National Documentation Center of National Research Institute. In 1995 he joined SPACETEC Ltd. where he was Technical Project Manager for VISA/EMEA VSAT Project in Greece. In 1996 he joined the Mobile Radio Communications Laboratory as a research associate. From 1999 to 2002 he was with the Institute of Communication & Computer Systems. In 2000 he became a member of the Board of Directors of OTESAT S.A. He is an Assistant Professor in the Department of Technology Education and Digital Systems at University of Piraeus. His current research interests include channel characterization and estimation, simulation and modeling for mobile, mobile satellite, and future wireless communication systems. He has been a Senior Member of IEEE since 2002, and is also a member of the Technical Chamber of Greece. In 1999 he was elected Chairman of the Communications Society of the Greek IEEE Section. Panagiotis I. Dallas was born 1967 in Thessaloniki, Greece. He obtained his diploma and Ph.D. degree from the Electrical and Computer Engineering Department of Aristotle University of Thessaloniki, Greece, in 1990 and 1997, respectively. Since 1998 he joined with INTRACOM where he currently is Section Manager of Advanced Communications Technologies branch of Emerging Technologies & Markets department, leading the next generation of broadband wireless access systems for internal and EU projects. He runs the relevant standardization activities (IEEE 802.16 and ETSI/BRAN HIPERMAN) in INTRACOM and he represents the company in WiMAX forum. Finally, he has over 30 publications in international journals and conferences. Philip Constantinou received the Diploma in Physics from the National University of Athens in 1972, the Master of Applied Science in Electrical Engineering from the University of Ottawa, Ontario, Canada in 1976, and the Ph.D. degree in Electrical Engineering in 1983 from Carleton University, Ottawa, Ontario, Canada. From 1976 to 1979 he was with Telesat Canada as a Communications System Engineer. In 1980 he joined the Ministry of Communications in Ottawa, Canada where he was engaged in the area of Mobile Communication. From 1984 to 1989 he was with the National Research Center Demokritos in Athens, Greece where he was involved in several research projects in the area of Mobile Communications. In 1989 he joined the National Technical University of Athens where he is currently a Professor and Director of the Mobile Radio Communications Laboratory. His current research interests include Personal Communications, Mobile Satellite Communications, and Interference Problems on Digital Communications Systems.     

基于PC机的广播节目自动识别系统的研究

广播节目识别系统主要用于广播发射机房中,该系统能同时对4路输入的广播节目信号进行采集与识别,如果存在一路不同的节目信号,系统将指示该路异常,发出警告并自动禁止该路输出,同时输出具有最佳信噪比的音频广播节目。在提出判别这些音频信号波形相似性的理论基础上,着重论述了在PC机基础上,利用音频数据采集卡,对采集输入的广播节目信号进行判断识别的实现方法。最后给出了带噪声时的相同音频信号的识别结果。