基于通信信道的视频传输系统的设计

提出了一种利用PCM基群信道进行视频信号传输的方法,介绍了传输系统的工作原理,对视频编码器进行了较为详细的分析,并采用数字信号处理器作控制器,实现了视频信号的实时传输。     

On Striping Traffic over Multiple IEEE 802.11(b) Wireless Channels

Due to interference, path loss, multipath fading, background noise, and many other factors, wireless communication normally cannot provide a wireless link with both a high data rate and a long transmission range. To address this problem, striping network traffic in parallel over multiple lower-data-rate but longer-transmission-range wireless channels may be used. In this paper, we propose a new striping method and evaluate its performances over multiple IEEE 802.11(b) channels under various conditions. Our extensive simulation results show that this method is quite effective for such an application. S.Y. Wang is an Associate Professor of the Department of Computer Science and Information Engineering at National Chiao Tung University, Taiwan. He received his Master and Ph.D. degree in computer science from Harvard University in 1997 and 1999, respectively. His research interests include wireless networks, Internet technologies, network simulations, and operating systems. He is the author of the NCTUns 2.0 network simulator and emulator, which is being widely used by network and communication researchers. More information about the tool is available at http://NSL.csie.nctu.edu.tw/nctuns.html. C.H. Hwang received his master degree in computer science from NCTU in 2002 and currently is working for a network company. C.L. Chou currently is a third-year Ph.D. student at the Department of Computer Science and Information Engineering, National Chiao TungUniversity (NCTU), Taiwan. He received his master degree in computer science from NCTU in 2002.     

油井远程智能监控系统

根据采油厂油井监控的需求,将油井数据采集、网络视频监控技术和无线通信技术紧密结合起来,设计规划适用于油井的远程智能监控系统。重点介绍了远程智能监控技术的系统原理、组成结构、实现方式及其实际应用效果。     

H.323同步控制实现研究

提出并实现了一种H.323多媒体通信系统音视频同步控制算法,算法以正常语音播放为基准,利用H.263码流语法信息,通过调整视频播放帧率实现媒体间同步, 不增加通信冗余度。实际测试结果表明,算法有效地提高了多媒体通信系统音视频媒体同步性能和多媒体的感知服务质量,并已应用于实际多媒体通信系统。     

无线网络中TCP与Ipsec的兼容性研究

针对有线网络设计的传输控制协议(TCP),在应用到无线环境中时存在许多不兼容问题,必须对TCP进行修改.目前人们提出了几种对TCP协议在无线网络环境下的改进方案,但是这些改进方案同IP安全协议(IPsec)存在一定的中突.文章分析了IPsec与TCP的改进方案之间的冲突问题,给出了4种解决方案:用传输层安全协议/安全套接层协议(TLS/SSL)代替IPsec、扩展封装安全载荷(ESP)协议、对TCP路径分段和修改IPsec的端到端保护模式,并分析了各方案的优缺点.     

VOD在有线电视网的实现

从视频点播系统的结构及组成和在有线电视网络中VOD系统的结构模式与应用两个方面，详细地阐述了如何利用有线电视网络实现视频点播，主要从以下3个方面介绍关于视频点播系统VOD技术：①视频点播VOD的技术原理；②视频点播系统的结构及组成；③有线电视视频点播系统的结构模式与应用。     

Endoscopic Observation of Tissue by Narrowband Illumination

We propose a new illumination method for a medical endoscope: narrow band imaging (NBI), in which the spectral bandwidth of the filtered light is narrowed. To confirm how the spectral specifications of the filtered light influence a reproduced image, an experiment was conducted observing the endoscopic images of the back mucosa of a human tongue. In addition, the effect of NBI on endoscopic images was investigated through preliminary clinical tests in colonoscopy and upper gastrointestinal endoscopy. It has been shown that NBI can enhance the capillary pattern and the crypt pattern on the mucosa. These patterns are useful features for diagnosing an early cancer.     

地面数字声音广播（DAB）及其覆盖规划的考虑

简要描述了近几年来研究开发的为移动、便携和固定接收服务的地面发射数字声音广播(DAB)系统总的特点、应达到的技术和运行要求。重点介绍了系统采用的最适合克服移动接收中出现的多径效应影响的先进源编码技术(MUSICAM)、信道编码技术(COFDM)等的基本原理、系统参数、并介绍了规划DAB业务时,在VHF/FM频段考虑的最佳频段及频谱利用改善情况,还提供了DAB单频网洛(SFN)覆盖的大体情况。其内容取材均来自1990～1992年EBU、CCIR等的最新文稿资料。     

MMDS技术综述

本文介绍多点多频道电视信号开路分配服务系统,并简述了传输接收技术。     

ATM技术在校园网中的实时性应用

讨论了ＡＴＭ论坛关于局域网仿真技术的基本思想及其协议体系的工作过程，并介绍了利用局域网仿真技术在校园网中应用ＡＴＭ技术实现视频传输的方法。