数码视讯致力基于DSP硬件系统的研制

1前言MPEG-4标准是国际标准化组织(ISO)运动图像专家组(MPEG委员会)在1999年推出的关于视音频编解码技术及系统的标准及规格。MPEG-4标准的目标与MPEG-1/2的标准有较大的不同，其应用领域更为广泛、应用前景更加广阔。MPEG-4标准的主要目标体现在以下三个方面：(1)MPEG-4是基于对象的压缩标准，与MPEG-1/2的基于图像块的压缩不同；(2)MPEG-4具有可交互性的特点；(3)MPEG-4输出码率适应性更强，尤其是低码率的压缩。正是由于MPEG-4标准以上所确立的目标，MPEG-4的发展带来了很多机遇，同时也迎来了很多挑战。比如MPEG-4…     

MPEG—4系统浅析

MPEG-4系统因为MPEG-4标准所设定应用目标的特点;与以往的MPEG-1/2系统有了许多不同或是说有了许多新的内容,本文力求简明地阐述MPEG-4系统的内容和特点,并部分地与MPEG-2系统做了简要的比较。     

基于MPEG-4的数字监控系统

介绍了一种基于MPEG-4的数字监控系统的系统构成和软件实现方法。该系统采用MPEG-4标准压缩方法,比较其他压缩方法其压缩比更大。通过对MPEG压缩原理的分析,比较了MPEG-1、MPEG-2和MPEG-4三种标准,说明MPEG-4采用视频对象VO的概念进行编码,更适合远程数字监控。     

基于IOCP的MPEG-4出租车无线视频监控系统设计与实现

研究了基于IOCP的MPEG-4解码出租车视频监控系统。设计并实现了软件整体模型，对各个功能模块作出了分析。系统中使用了IOCP技术进行传送，XviD实现MPEG-4解压，MySQL构建网络数据库。     

基于MPEG-4标准和嵌入式技术的数字监控系统

本文介绍了基于内容的视频压缩标准MPEG-4和嵌入式系统在数字监控领域中的应用，并且给出了一种在嵌入式系统软件平台上实现MPEG-4的方法。     

基于MPEG-4视频采集PCI板卡的设计与实现

介绍一种基于MPEG-4的视频压缩编码卡。该板卡为4路的编码PCI卡，将采集到的模拟视频图像以MPEG-4的方式进行压缩处理。使用标准PCI2．2的规范，完成有CPU控制板与编码PCI卡之间的通信，使CPU控制板通过一块桥芯片可以访问编码芯片内部寄存器，读出编码芯片压缩的MPEG-4的视频压缩流、音频压缩流。从而使压缩的MPEG-4数据完成远程传输或本地存贮。另一个是完成视频预览功能。该板卡为实现远程实时监控提供了必要的硬件设备，他以最新的MPEG-4压缩方式进行编码，对整个数字监控系统和视频网络传输系统提供了最优化的硬件设计，使视频数据数字化管理更加方便、可靠，也使整个系统在市场竞争中更具有活力。     

视频点播中的MPEG-4封装技术

宽带网络的讯速发展，为网络流媒体应用展现了广阔的前景，MPEG-4具有的高压缩率，强交互性和灵活分级扩展的特性使之特别适合网络流好媒体应用。本就MPEG-4在网络流媒体应用中的关键问题——MPEG-4的RTP封装技术进行了深入研究，并成功将其应用到视频点播系统中。     

MPEG-4编解码算法及其视频性能分析

3G移动终端要求能够提供包含语音、数据和图像的多媒体业务，为此3GPP制定了第一个适合3G系统的基于电路交换的多媒体终端模型——3G-324M规范，该模型支持MPEG-4视频处理，它具有高压缩比和容错编码特性。在研究MPEG-4编解码算法基础上进行了MPEG-4视频编码的性能测试。     

基于MPC850的四路MPEG-4视频监控系统的设计实现

本方介绍了基于PowerPC内核的嵌入式通信控制器芯片MPC850和MPEG-4数字视频压缩芯片IME6400，并利用这些芯片设计并实现了一种新型的MPEG-4数字视频监控系统。     

MPEG—4中的视频编码技术

MPEG-4图像压缩编码方法是基于对象和内容的现代编码方法，顺应了现代图像压缩编码的潮流，广泛用在多媒体通信及第三代移动通信系统中。本主要介绍了MPEG-4视频对象的压缩编码方法及其差错控制方法。     

Alternative Schemes for Dynamic Secure VPN Deployment in UMTS

Three alternative schemes for secure Virtual Private Network (VPN) deployment over the Universal Mobile Telecommunication System (UMTS) are proposed and analyzed. The proposed schemes enable a mobile node to voluntarily establish an IPsec-based secure channel to a private network. The alternative schemes differ in the location where the IPsec functionality is placed within the UMTS network architecture (mobile node, access network, and UMTS network border), depending on the employed security model, and whether data in transit are ever in clear-text, or available to be tapped by outsiders. The provided levels of privacy in the deployed VPN schemes, as well as the employed authentication models are examined. An analysis in terms of cost, complexity, and performance overhead that each method imposes to the underlying network architecture, as well as to the mobile devices is presented. The level of system reliability and scalability in granting security services is presented. The VPN management, usability, and trusted relations, as well as their behavior when a mobile user moves are analyzed. The use of special applications that require access to encapsulated data traffic is explored. Finally, an overall comparison of the proposed schemes from the security and operation point of view summarizes their relative performance. Christos Xenakis received his B.Sc. degree in computer science in 1993 and his M.Sc. degree in telecommunication and computer networks in 1996, both from the Department of Informatics and Telecommunications, University of Athens, Greece. In 2004 he received his Ph.D. from the University of Athens (Department of Informatics and Telecommunications). From 1998–2000 was with the Greek telecoms system development firm Teletel S.A., where was involved in the design and development of advanced telecommunications subsystems for ISDN, ATM, GSM, and GPRS. Since 1996 he has been a member of the Communication Networks Laboratory of the University of Athens. He has participated in numerous projects realized in the context of EU Programs (ACTS, ESPRIT, IST). His research interests are in the field of mobile/wireless networks, security and distributed network management. He is the author of over 15 papers in the above areas. Lazaros Merakos received the Diploma in electrical and mechanical engineering from the National Technical University of Athens, Greece, in 1978, and the M.S. and Ph.D. degrees in electrical engineering from the State University of New York, Buffalo, in 1981 and 1984, respectively. From 1983 to 1986, he was on the faculty of Electrical Engineering and Computer Science at the University of Connecticut, Storrs. From 1986 to 1994 he was on the faculty of the Electrical and Computer Engineering Department at Northeastern University, Boston, MA. During the period 1993–1994 he served as Director of the Communications and Digital Processing Research Center at Northeastern University. During the summers of 1990 and 1991, he was a Visiting Scientist at the IBM T. J. Watson Research Center, Yorktown Heights, NY. In 1994, he joined the faculty of the University of Athens, Athens, Greece, where he is presently a Professor in the Department of Informatics and Telecommunications, and Director of the Communication Networks Laboratory (UoA-CNL) and the Networks Operations and Management Center. His research interests are in the design and performance analysis of broadband networks, and wireless/mobile communication systems and services. He has authored more than 150 papers in the above areas. Since 1995, he is leading the research activities of UoA-CNL in the area of mobile communications, in the framework of the Advanced Communication Technologies & Services (ACTS) and Information Society Technologies (IST) programmes funded by the European Union (projects RAINBOW, Magic WAND, WINE, MOBIVAS, POLOS, ANWIRE). He is chairman of the board of the Greek Universities Network, the Greek Schools Network, and member of the board of the Greek Research Network. In 1994, he received the Guanella Award for the Best Paper presented at the International Zurich Seminar on Mobile Communications.     

On Fixed-Mobile Network Convergence

As the convergence in digital industry takes shape, the digital networks, both wireline and wireless, are also converging to offer seamless services and enhanced experience to the user. With the arrival of the mobile Internet the mobility is also moving into new areas, e.g., imaging, games, video, multimedia, and across different types of networks. In this paper we explore why, what, and how of the network convergence, and identify how the industry viewpoints align and differ. We also identify the key barriers to achieving true network convergence. We then discuss the role of the Internet Protocol (IP) as the common thread that enables network convergence, and the key industry and standards initiatives to actually provide solutions and the equipment to implement a cost-efficient and high performance converged network. Sudhir Dixit joined Nokia Research Center in 1996, where he is currently a Research Fellow and works on next generation wireless networks. From 1996 to 2003 he was a Senior Research Manager, focusing on IP/ATM, wireless, content networks, and optical networks. Prior to that he worked at NYNEX Science & Technology (now Verizon), GTE (now Verizon), Codex Motorola, Wang, Harris, and STL (now Nortel Europe Labs). He has published or presented over 150 papers, published three books, and holds 14 patents. He is on the Editorial Board of the IEEE Communications Magazine, Springer's Wireless Personal Communications Journal, and KIC's Journal of Communications and Networks. He received a B.E. degree from MANIT, Bhopal, India, an M.E. degree from BITS, Pilani, India, a Ph.D. degree from the University of Strathclyde, Glasgow, Scotland, and an M.B.A. degree from Florida Institute of Technology, Melbourne. He is a Fellow of IEE (UK) and IETE (India). He represents Nokia on the Steering Board of the Wireless World Research Forum, and is also Chair of the SIG on Self-Organization of Wireless World Systems.     

Wireless IP and Its Challenges for the Heterogeneous Environment

The tremendous momentum toward building a mobile wireless Internet using the Internet Protocol (IP) has thrust many challenges upon the technology developers and the operators. These challenges encompass the 2.5G, 3G, and future solutions and standards. Some of the key issues deal with supporting IP traffic across different wireless and MAC protocols, end-to-end QoS and mobility, traffic engineering and scalability, protection/restoration, operations and management, authentication/privacy/security, billing, and content and context aware networking. This article addresses the drivers, the issues, and solutions (wherever possible) in the above areas, and concludes with a summarization of the challenges that lie ahead.     

单目图像序列光流三维重建技术研究综述

由单目图像序列光流重建物体或场景的三维运动与结构是计算机视觉、图像处理与模式识别等领域的重要研究内容,在机器人视觉、无人机导航、车辆辅助驾驶以及医学影像分析等方面具有重要的应用。本文首先从精度与鲁棒性等方面对单目图像序列光流计算及三维重建技术近年来取得的进展进行综述与分析。然后采用Middlebury测试图像序列对HS、LDOF、CLG-TV、SOF、AOFSCNN 和 Classic ＋NL 等典型光流算法以及 Adiv、RMROF、Sekkati 和DMDPOF等基于光流的间接与直接重建方法进行实验对比分析,指出各对比方法的优点与不足,归纳各类方法的性能特点与适用范围。最后对利用分数阶微分模型、非局部约束、立体视觉以及深度线索解决亮度突变、非刚性运动、运动遮挡与模糊情况下光流计算及重建模型的局限性与鲁棒性问题进行总结与展望。     

一种智慧协同网络多参数的多路径路由算法

多路径路由技术采用多条路径同时传输,作为优化资源配置和负载均衡的重要技术,在路由可靠性、QoS路由、传输效率等多方面比单路径传输具有优势.现有互联网网络资源配置和路由机制相对静态和僵化,导致多路径技术的发展存在发展的局限性.现有多路径技术考虑在路由层面不利于多路径路由选择和计算,难以保证传输性能,降低网络传输效率.智慧协同网络能够动态感知网络需求,灵活适配网络资源,更好的支持路由可扩展性.本文在智慧协同网络架构下提出了一种智慧协同网络多参数的多路径路由算法.该算法制定了智慧协同网络多参数的多路径路由协议,对网络性能参数CPU占用率、往返时延(RTT)、带宽进行加权计算得到路径权重值,根据权重值进行流量分配.采用图论理论对网络流量分配及模型进行了分析.并在Mini-Net平台上进行了开发和实验,结果表明,该算法能够优化网络配置,减小往返时延,提高网络吞吐量,从而提高网络性能,实现负载均衡.     

A Novel Local-Dielectric-Thickening Technique for Performance Improvements of Spiral Inductors on Si Substrates

A novel local-dielectric-thickening technique is presented for performance improvements of Si-based spiral inductors.This technique employs the processes of deposition,photolithography,and wet-etching,to locally thicken the oxide layer under the inductor,which can decrease the substrate loss and improve the inductor performance.Both the structures and processes are compact,economical,and compatible with CMOS processing.Several square spiral inductors with different inductances are fabricated,and the quality factors and the self-resonant frequencies both increase clearly with this proposed technique:for the 10,5，and 2nH inductors,the peak quality factors are effectively improved by 46.7%,49.7%，and 686%,respectively;however,the improvement percents of the selfresonant frequencies are more significant,which are 92.1%,91.0%,and no less than 68.1%，respectively.     

攀枝花广电工程项目管理策略与方法运用

工程项目管理就是要求工程建设任务在规定的时间和成本控制范围内达到预期的各项管控目的,它贯穿于项目的设计、施工准备与施工、使用与维护3个阶段,重点是施工准备与施工阶段的安全、质量、成本、进度、合同方面的控制与管理。结合工作实践,介绍了攀枝花市广电工程建设项目在施工准备与施工过程中的管理策略及其方法运用。     

卫星遥感温室气体的大气观测技术进展

全球、区域及城市的碳浓度、碳源汇信息是应对气候变化、达成双碳目标、完善国际谈判、支持治理政策制定与执行的重要依据。国际认可的“自上而下” 方法将卫星观测作为基础的通量计算技术, 是验证温室气体排放清单的重要手段。系统介绍了温室气体的卫星探测载荷原理、类别和发展, 以及反演、估算CO2、CH4 和N2O 的浓度和排放通量的方法, 还有探测缺失和误差存在的影响因素等; 分析了对卫星探测温室气体能力提高的迫切需求, 浓度反演和排放量估算精度不足, 以及N2O、氟化物等其他温室气体遥感研究缺乏、地基遥感验证能力薄弱等问题; 最后总结了我国温室气体卫星遥感技术的发展趋势, 主要是面向主被动高时空分辨率卫星的研制应用、高精度多尺度排放量估算(特别针对城市、小区域和点源尺度)、氟化物遥感评估等主题, 以加强对碳排放的量化观测, 并增强对碳循环的理解, 提高感知和应对气候变化的能力。     

基于声卡的虚拟示波器设计

随着现代科学和信息技术的不断进步,示波器作为一种电子测量处理仪器也在不断发展并且已经变的越来越精密,也越来越智能.传统的模拟示波器受到低频响应能力和带宽限制等多方面因素影响在很多领域已显得力不从心,虚拟示波器的出现很好的解决了这些问题.本文以LabVIEW18版本为开发平台,设计制作了一款基于声卡的虚拟示波器.重点介绍...     

机动6m抛物面天线车结构总体方案探讨

文章遵循策划、分解、综合及优化的总体方案研究思路,根据要求,提出了三个机动6 m抛物面天线车结构总体备选方案;针对系统结构组成,详细分析了天馈线、天线座、拖车以及系统标定等子系统所有可能的结构方案;最后综合权衡研究三个备选方案在技术、质量、成本、周期等多方面的优劣,选择了最佳结构总体方案,确保了所选方案具有合理性、可行性、经济性、先进性和科学性。实践证明,所选方案用户满意,实施效果良好。