基于数学形态学的红外图像小目标检测

针对红外成像跟踪系统的低信噪比、背景和噪声干扰严重的小目标图像,以及后续的目标识别处理需要目标的灰度信息的特点,设计了一种基于数学形态学的红外灰度图像小目标检测算法,并用FPGA硬件实现。实验表明,数学形态学滤波能够大大提高目标的信噪比,去除背景和噪声干扰,保留目标的灰度信息,满足系统实时性要求,是一种有效的红外灰度图像小目标检测算法。     

引入激光回馈的双光束干涉效应的研究

提出了一种引入He-Ne激光回馈的双光束干涉系统,并在理论和实验两方面进行了研究。实验中对系统中的干涉信号及激光器尾光功率变化同时进行探测。发现当干涉仪的主回馈镜移动时,激光器尾光信号是正弦形波形,而干涉仪输出的是以双峰为一个周期的信号,双峰中一峰总是高于另一峰,并且当主回馈镜移动方向改变时,同一周期中两峰出现的顺序也随之改变。对实验现象进行了理论分析,并模拟出干涉信号及激光自身功率的变化曲线。理论分析及模拟结果与实验结果完全吻合。讨论了利用发现的现象进行测量的可行性,所提出的测量方法易于实现。     

简单可靠的两片式电子镇流器设计

FAN7527和KA7541分别是FairchildSemiconductor公司生产的高效低功耗PFC控制器和电子镇流器控制器。文中介绍了它们的主要特点和引脚功能 ,给出了用FAN7527进行功率因数校正 ,并选用KA7541作为荧光灯电子镇流器控制器设计的、简单、可靠且成本低廉的新型电子镇流器的电路设计方案     

农村通信如何"突围"

农村通信作为农村地区信息化的基础，对于全面建设小康具有特殊的重要地位。介绍了我国农村通信的发展现状，分析了农村通信发展的困难压其原因，最后对农村压边远、欠发达地区通信的均衡震展提出了一些建议。     

三网融合存在的技术问题及其发展的探讨

目前加快网络融合的呼声日趋高涨，从传输、交换、接入3个方面探讨了目前三网融合在技术上存在的一些问题及其解决方案的发展动向，并指出三网融合虽然是大趋势，但需要解决的实际问题还很多，融合的过程也较为缓慢。     

精密微处理器监控技术及应用

介绍微处理器μP监控技术的原理与应用，并以MAX808 μP监控器为例，讨论μP监控技术在便携式CATV网络检测仪器中的应用。     

宽带电流反馈运算放大器OPA623及其应用

以电流模技术和互补双极工艺制造的集成电路具有良好的高频性能，用其构成的电流反馈放大器频带宽，转换速率高，在视频和射频信号的放大和处理以及高速数字通信系统中都得到广泛的应用。通过OPA623集成“运放”，简要介绍电流反馈放大器的原理、性能及其在高清晰度电视及有线电视传输中的应用。     

W波段折叠波导慢波结构设计及三维注波互作用模拟

本文综合分析了折叠波导的几何尺寸和电子束参数，运用电磁场软件MAFIA的粒子模拟程序对三维折叠波导慢波结构进行了模拟．模型中，电磁波通过波导模式导入；为了克服较大空间电荷效应造成的电子注发散，使用了纵向聚焦磁场．基于三维互作用模型得到了W波段折叠波导的模拟结果，该结果可以对折叠波导慢波结构的三维互作用性能进行预测和分析．     

外腔半导体激光器的空间模式特性分析

通过对宽发光截面半导体激光器(BAL)输出激光空间特性和远场分布的理论分析,并根据激光振荡的自再现原理,导出了反馈注入外腔宽发光截面半导体激光器输出激光的光场分布。计算表明外腔的反馈作用可以看作是频谱面上引入了一个带通滤波器,通过选择特定模式的频谱分量进行反馈注入,从而实现选模和改善输出激光光束质量的目的。完成了相应的外腔反馈注入宽发光截面半导体激光器的实验,获得了单瓣近衍射极限的激光输出,在工作电流为1.18倍阈值电流时,获得远场发散角为0.074°的输出激光,计算得相应的光束衍射倍率因子M2为1.16,和理论计算的结果基本吻合。     

Analysis and Optimization of the Energy Efficiency in the 802.11 DCF

This paper introduces an analytical model to investigate the energy efficiency of the IEEE 802.11 distributed coordinated function (DCF). This model not only accounts for the number of contending nodes, the contention window, but also the packet size, and the channel condition. Based on this model, we identify the tradeoff in choosing optimum parameters to optimize the energy efficiency of DCF in the error-prone environment. The effects of contention window and packet size on the energy efficiency are examined and compared for both DCF basic scheme and DCF with four-way handshaking. The maximum energy efficiency can be obtained by combining both the optimal packet size and optimal contention window. To validate our analysis, we have done extensive simulations in ns-2, and simulation results seem to match well with the presented analytical results. The Ohio Board of Regents Doctoral Enhancements Funds and the National Science Foundation under Grant CCR 0113361 have supported this work. Xiaodong Wang received his B.S. degree in communication engineering from Beijing Information Technical Institute of China in 1995, and his M.S. degree in electric engineering from Beijing University of Aeronautics and Astronautics of China in 1998. He joined China Telecom in 1998 where he worked on communication protocols for telecommunication. From June 2000 to July 2002, he worked on GSM base station software development at Bell-labs China, Beijing, China. Currently he is a Ph.D. student in Computer Engineering at University of Cincinnati. His research activities include wireless MAC protocols, energy saving for wireless sensor networks. He is a student member of the IEEE. Jun Yin received the BS degree in automatic control from Dalian Railway Institute of China in 1997, and the MS degree in flight control from Beijing University of Aeronautics and Astronautics of China in 2001. Since 2001 she has been a Ph.D. student in the OBR Research Center for Distributed and Mobile Computing at the University of Cincinnati. Her research interests include performance evaluation of 802.11 MAC protocol, wireless ad hoc networks and sensor networks. She is a student member of the IEEE. Dharma P.Agrawal IEEE Fellow, 1987; ACM Fellow, 1998; AAAS Fellow, 2003 Dr. Agrawal is the Ohio Board of Regents Distinguished Professor of Computer Science and Computer Engineering in the department of Electrical and Computer Engineering and Computer Science, University of Cincinnati, OH. He has been a faculty member at Wayne State University, (1977–1982) and North Carolina State University (1982–1998). He has been a consultant to the General Dynamics Land Systems Division, Battelle, Inc., and the U. S. Army. He has held visiting appointment at AIRMICS, Atlanta, GA, and the AT&T Advanced Communications Laboratory, Whippany, NJ. He has published a number of papers in the areas of Parallel System Architecture, Multi computer Networks, Routing Techniques, Parallelism Detection and Scheduling Techniques, Reliability of Real-Time Distributed Systems, Modeling of C-MOS Circuits, and Computer Arithmetic. His recent research interest includes energy efficient routing, information retrieval, and secured communication in ad hoc and sensor networks, effective handoff handling and multicasting in integrated wireless networks, interference analysis in piconets and routing in scatternet, use of smart directional antennas (multibeam) for enhanced QoS, Scheduling of periodic real-time applications and automatic load balancing in heterogeneous workstation environment. He has four approved patents and three patent filings in the area of wireless cellular networks.