便携式无线通信中的陶瓷技术

重点讨论了现代无线通信中关键元器件之一滤波器的发展进程,中、高频及微波滤波器的主要类型及性能特点。低损耗、高介电常数陶瓷在RF和IF滤波器中的应用,能够实现无线设备的微型化。对制备滤波器的介质陶瓷材料的要求是:在所使用的波段内,相对介电常数r要大,可缩小介质元件的尺寸;品质因数Q要高,可获得良好的滤波特性及通讯质量;谐振频率的温度系数f接近于零或可调节,以达到整机电子回路的要求。     

A Review of Wavelets for Digital Wireless Communication

Wavelets have been favorably applied in almost all aspects of digital wireless communication systems including data compression, source and channel coding, signal denoising, channel modeling and design of transceivers. The main property of wavelets in these applications is in their flexibility and ability to characterize signals accurately. In this paper recent trends and developments in the use of wavelets in wireless communications are reviewed. Major applications of wavelets in wireless channel modeling, interference mitigation, denoising, OFDM modulation, multiple access, Ultra Wideband communications, cognitive radio and wireless networks are surveyed. The confluence of information and communication technologies and the possibility of ubiquitous connectivity have posed a challenge to developing technologies and architectures capable of handling large volumes of data under severe resource constraints such as power and bandwidth. Wavelets are uniquely qualified to address this challenge. The flexibility and adaptation provided by wavelets have made wavelet technology a strong candidate for future wireless communication. Madan Kumar Lakshmanan was born in Chennai, India, in 1979. He received the B.E. (with distinction) in electrical engineering from the University of Madras, Chennai, India, in 2000. He joined the Indian Software firm, Polaris Software Labs Ltd., in 2000 where he wrote software for Telecommunication applications. At Polaris, he was awarded the “On The Spot Of Excellence Award” for his efforts. In 2003, he moved to the Indian Institute of Technology-Madras, to develop and establish a wireless communications network for rural connectivity. In 2004, he was awarded the Royal Dutch/Shell Chevning scholarship to pursue a Master degree in Telecommunications at the Delft University of Technology (TUDelft). At TUDelft he is affiliated to the International Research Center for Telecommunications-Transmission and Radar (IRCTR) where he is undertaking research in the field of wavelets applications in Wireless Communications. Homayoun Nikookar received his Ph.D. in Electrical Engineering from Delft University of Technology (TUDelft), The Netherlands, in 1995. From 1995 to 1998 he was a postdoc researcher at the International Research Center for Telecommunications-Transmission and Radar, TUDelft, where since 1999 he has been an Assistant Professor. Dr. Nikookar has done research on different areas of wireless communications, including wireless channel modeling, UWB, MIMO, multicarrier transmission, Wavelet-based OFDM and CDMA. He is a senior member of the IEEE.     

Delay-insensitive codes — an overview

The problem of delay-insensitive data communication is described. The notion of delay-insensitive code is defined, giving precise conditions under which delay-insensitive data communication is feasible. Examples of these codes are presented and analyzed. It appears that delay-insensitive codes are equivalent with antichains in partially ordered sets and with all unidirectional error-detecting codes. Tom Verhoeff received the B.S. and M.S. degrees in mathematics from Eindhoven University of Technology, The Netherlands, in 1985. He is currently an Assistant Professor at the Department of Mathematics and Computing Science of the same university. His main research interests are parallel computations, especially formalisms for their specification and design, and their implementation as delay-insensitive VLSI circuits.     

A Study of Shadowing on Indoor Visible-Light Wireless Communication Utilizing Plural White LED Lightings

White LED is considered as a strong candidate for the future lighting technology. We have proposed an optical wireless communication system that employs white LEDs for indoor wireless networks. In this system, LED is used not only as a lighting device, but also as a communication device. The transmitter has large optical power and large emission characteristics to function as lighting device. And the system has specific wireless channel impulse response differing from infrared wireless communication. In this paper, we discuss about shadowing effect on the system utilizing plural LED lightings including the performance of ISI based on the impulse response. We consider the downlink transmission based on TDMA and evaluate the shadowing effect caused by pedestrians with computer simulation. When the shadowing often occurs at 800 Mb/s, the performance of outage call duration rate and blocking rate are improved by using 3 LED lightings compared with 1 or 2 LED lightings. And, we show that the system with the optimal number of the LED lighting is robust against shadowing and can accommodate more calls. Toshihiko Komine was born in Shizuoka, Japan, on November 17, 1978. He received the B.E. and M.E. degrees in Information and Computer Science from Keio University, Yokohama, Japan, in 2001 and 2003 respectively. He is currently studying for the Ph.D. degree at Department of Information and Computer Science, Keio University. His current research interests are optical wireless communications and LED communications. Shinichiro Haruyama is a professor at Department of Information and Computer Science, Faculty of Science and Technology, Keio University, Yokohama, Japan. He received an M.S. in engineering science from University of California at Berkeley in 1983 and a Ph.D. in computer science from the University of Texas at Austin in 1990. He worked for Bell Laboratories of AT{&}T and Lucent Technologies, U.S.A from 1991 to 1996, and for Sony Computer Science Laboratories, Inc. from 1998 to 2002. His research interests include reconfigurable system, system design automation, wireless communication, and visible light communication. Masao Nakagawa was born in Tokyo, Japan in 1946. He received the B.E., M.E. and Ph.D. degrees in electrical engineering from Keio University, Yokohama, Japan, in 1969, 1971 and 1974 respectively. Since 1973, he has been with the Department of Electrical Engineering, Keio University, where he is now a Professor. His research interests are in CDMA, consumer Communications, Mobile communications, ITS (Intelligent Transport Systems), Wireless Home Networks, and Visible light Communication. He received 1989 IEEE Consumer Electronics Society Paper Award, 1999-Fall Best Paper Award in IEEE VTC, IEICE Achievement Award in 2000, IEICE Fellow Award in 2001. He was the executive committee chairman on International Symposium on Spread Spectrum Techniques and Applications in 1992 and the technical program committee chairman of ISITA (International Symposium on Spread Spectrum Techniques and Applications) in 1994. He is an editor of Wireless Personal Communications and was a guest editor of the special issues on “CDMA Networks I, II, III and IV” published in IEEE JSAC in 1994 (I and II) and 1996 (III and IV). He chairs the Wireless Home Link sub-committee in MMAC (Multimedia Mobile Access Communication Promotion Committee).     

智能化通信电源监控系统

以80C552单片机为核心,介绍了一种实现智能化电源监控系统的软、硬件设计。     

基于DVB/MPEG-2的卫星Internet技术

Internet的快速发展，使他已陷入了自身难以克服的困境，这种困境主要来自于骨干网、接入网、服务器三种瓶颈。而卫星通信与Internet的结合能有效地解决目前的这种困境。本文介绍了基于DVB／MPEG-2的卫星Internet原理、结构、应用及其关键技术，并引入了2种现有成熟的Internet接入技术：VSAT接入方式和VSAT与CATV结合接入方式。     

图像边缘检测在关节镜图像处理中的应用

主要论述了采用图像边缘检测和图像跟踪算法对采集的关节镜图像进行图像处理和分析的过程。在图像处理的基础上，系统自动测量出指定目标的形状参数，实现了系统的测量要求。本研究为实现关节镜手术过程图像的保存和手术的准确性提供了可行的方法。     

差分跳频系统对抗初探

以CHESS系统为例,介绍了差分跳频通信系统的基本原理,对其抗常规有意干扰的性能作了简要分析;在此基础上,初步探索了对CHESS系统进行侦察干扰的方法,并在计算机上对干扰效果进行了仿真比较。     

Maternal Power Assertion in Discipline and Moral Discourse Contexts: Commonalities, Differences, and Implications for Children's Moral Conduct and Cognition.

Parental power assertion is traditionally studied in the behavioral domain--discipline triggered by the child's immediate misbehavior--but rarely in the cognitive domain--parent-child discussions of the child's past misbehavior. Maternal power assertion was observed in "do" and "don't" discipline contexts from 14 to 45 months and in the context of mother-child discourse about a recent misbehavior at 56 months. Mothers' use of power cohered across the "do," "don't," and discourse contexts, but its implications were domain specific. Power assertion in the "don't" discipline context predicted behavioral outcomes (more moral conduct at 56 and 73 months, less antisocial conduct at 73 months) but not cognitive outcomes (moral cognition at 56 and 73 months). Power assertion in the discourse context predicted less mature moral cognition but not moral or antisocial conduct. Mothers' high Neuroticism predicted more power assertion in all three contexts. Child effects were examined. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Study of trace elements in coal and mining wastes and its significance in China

In the world energy about 26% of all was dedved from coal combustion. Nearly 80% of the electricity produced in China is generated from coal. Coal will play the most important role in the coming 50 years as the past century in China. However one consequentially of the mining and combustion of coal is the mobilization of trace elements, especially trace metals, which have environmental and human health significance. Information on concentrations and distributions of potentially toxic elements in coal, and information On the modes of occurrence of these elements and the relations of the minerals in coal can help to predict the behavior of the potentially toxic trace metals dudng cleaning, combustion, weathering, and leaching.