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中国移动十月预演手机电视据中国移动内部人士透露,中国移动全网手机电视业务将在10月下旬开通,届时全国的移动用户都可以通过手机收看手机电视剧《白骨精外传》。早在今年1月1日,500名上海移动用户就率先体验了手机电视业务,不过只限定在索爱、摩托罗拉和诺基亚的9款特定手机,由上海文广提供了4套电视节目的同步直播和10个类别的节目点播服务。5月13日,中国移动和上海文广签署战略合作协议,宣布将共同推出手机电视流媒体业务,并启动移动媒体娱乐平台。此前,中国联通早在去年就已推出了手机电视业务,相比之下,目前中移动采取的GPRS手机数据业务在传输速率和资费上并不占优势。目前手机电视的外部条件尚不成熟,网络传输带宽有限,具备看电视功能的手机种类少且平均价格在5000元以上,此外,手机电视业务资费昂贵,按流量估算,中国联通的手机电视业务每分钟流量费达25元,看1个小时就需要150元。但手机电视业务被认为是3G的杀手级应用,中国移动此举应该是为即将到来的3G做准备。(郑重)     

基于3G网络的手机移动视频监控系统的设计

为了解决传统固定视频采集实时传输系统的布线问题和基于GPRS/EDGE无线网络的远程视频传输系统的带宽问题,采用3G手机作为视频数据采集前端,在简述了H.264编码标准和RTP/RTCP协议原理的基础上提出一种基于3G网络的手机移动视频监控系统,并给出了硬件和软件的框架;最后,介绍了一些编写视频传输程序的方法。实验表明:在具体的设置特殊环境下达到了视频采集和实时传输的效果。     

SMTVS:一种基于H.264的手机电视系统

手机电视系统必须能够适应网络和客户端的异构性、无线信道的多变性等特点.提出一种手机电视系统SMTVS,流媒体服务器在不同码率的H.264视频流之间进行切换以适应网络状况的变化;代理服务器之间构成一个内容分送网络,视频数据通过应用层组播的方式传输到各个代理服务器,降低了服务器的负载,提高了网络资源利用率;代理服务器接收到视频数据之后,针对无线链路的状况对数据进行处理后再发送到客户端,以适应最终用户的不同需求;客户端根据网络状况来动态调整播放速率,避免显示缓冲区下溢和上溢.通过流媒体服务器、代理服务器以及客户端的协作,实现了视频数据在无线信道上的自适应传输.     

市场·新品视窗

近来,具备WAP功能的第三代移动电话为酷爱新技术的人们带来了无穷的想象力,手机已从单一的语音传输逐渐向数据、图像传输过渡.近日,三星电子宣布开发成功了世界上第一部便携式电视手机SCH-M220,它同时具备了电视播放和手机通话功能.它的出现,将使人们一边行走接听电话,一边观看体育、电视剧、综艺表演及其他各种电视节目的“异想天开”变为现实.     

3G时代最具潜力10大增值业务

◆手机音乐有望成为3G时代第一个高速发展的增值业务,由于市场需求的刺激,加上多方巨头的产业链合作,预计2007年将会以70亿左右的市场规模一举超过手机彩铃。◆手机电视在无线市场发达的韩国和日本,手机电视早已经实现大规模的商业应用。中国的手机电视市场在2006年也将有突破性进展。个性化服务、短平快的信息推送将会使手机电视成为一种广受欢迎的新媒体平台。◆手机游戏未来3年内“手机游戏+移动定位”、“手机游戏+手机搜索”和“手机游戏+手机媒体广告”等三种模式的融合将成为手机游戏行业的引擎。◆手机上网在3G时代,随着传统2G和2…     

支持无线网络的实时视频监控系统设计

为了解决有线网络视频监控的布线问题和工作人员的移动化监控问题,设计并实现了一种支持IP摄像头、DVR、3G手机作为视频数据采集前端,兼容H.264和MPEG4等编码标准和支持PC和3G手机进行客户端监看的实时视频监控系统,该系统实现视频的采集、压缩、传输、解码、显示、控制、录像、事件通知、电子地图等功能,该系统支持前端采集设备的多流输出和高并发访问,适应了3G手机的带宽,提高了服务器使用效率,达到了利用手机进行移动视频监控的目的。     

基于AVS的广播式手机电视系统

提出并实现了一种基于AVS的广播式手机电视系统,包括音视频数据的实时编码、系统层复用、T-DMB信号发射与接收、PC及手机平台的解码回放等,重点介绍了音视频编码器中的AVS视频编码算法的优化和复用器的实现,通过实验对编码器的性能进行了测试,对播放端的播放效果进行了分析。实验结果表明,AVS能够很好地应用于手机电视。     

基于3G/4G多旋翼飞行器的视频传输系统

为解决各行业进行高空拍摄时投入高、效果差,无法实时察看地面情况等问题,提出一种基于STM32微控制器的3G/4G多旋翼飞行器的视频传输系统解决方案。系统由多旋翼飞行器、3G/4G网络视频传输系统和地面智能手机控制平台等构成。试验表明,本方案通过3G/4G网络实现视频的传输,能够实现高空拍摄、视频传输、手机接收等功能,具有较好的实时性和可控性。     

基于3G/4G多旋翼飞行器的视频传输系统 基于3G/4G多旋翼飞行器的视频传输系统

为解决各行业进行高空拍摄时投入高、效果差,无法实时察看地面情况等问题,提出一种基于 STM32微控制器的3G/4G多旋翼飞行器的视频传输系统解决方案。系统由多旋翼飞行器、3G/4G网络视频传输系统和地面智能手机控制平台等构成。试验表明,本方案通过3G/4G网络实现视频的传输,能够实现高空拍摄、视频传输、手机接收等功能,具有较好的实时性和可控性。     

手机媒体业务迎来新拐点？

2009年2月18日,中国互联网络信息中心（CNNIC）在北京发布《中国手机媒体研究报告》,将手机媒体从应用上划分为手机报、手机音频广播,手机视频,手机电视和手机小说5种形式。毫无疑问,在这5种形式中,手机报和手机小说对于硬件和网络的要求相对较低。因此使用率更高。而手机音频广播、手机视频和手机电视则将在3G带来的行业发展浪潮前面临更大的机遇和挑战。     

European Community policy and the market

Abstract This paper starts with some reflections on the policy considerations and priorities which are shaping European Commission (EC) research programmes. Then it attempts to position the current projects which seek to capitalise on information and communications technologies for learning in relation to these priorities and the apparent realities of the marketplace. It concludes that while there are grounds to be optimistic about the contribution EC programmes can make to the efficiency and standard of education and training, they are still too technology driven.     

一种自适应子融合集成多分类器方法

融合集成方法已经广泛应用在模式识别领域,然而一些基分类器实时性能稳定性较差,导致多分类器融合性能差,针对上述问题本文提出了一种新的基于多分类器的子融合集成分类器系统。该方法考虑在度量层融合层次之上通过对各类基多分类器进行动态选择,票数最多的类别作为融合系统中对特征向量识别的类别,构成一种新的自适应子融合集成分类器方法。实验表明,该方法比传统的分类器以及分类融合方法识别准确率明显更高,具有更好的鲁棒性。     

煤矿井下安全监控分站的设计及其仿真实现

为了设计一种具有低成本、低功耗、易操作、功能强且可靠性高的煤矿井下安全分站,针对煤矿安全生产实际,文章提出了采用MCS-51系列单片机为核心、具有CAN总线通信接口的煤矿井下安全监控分站的设计方案;首先给出煤矿井下安全监控分站的整体构架设计,然后着重阐述模拟量输入信号处理系统的设计过程,最后说明单片机最小系统及其键盘、显示、报警、通信等各个组成部分的设计;为验证设计方案的可行性与有效性,使用Proteus软件对设计内容进行仿真验证,设计的煤矿井下安全监控分站具有瓦斯、温度等模拟量参数超标报警功能和电机开停、风门开闭等开关量指示功能;仿真结果表明:设计的煤矿井下安全监控分站具有一定的实际应用价值.     

Explanation and prediction: an architecture for default and abductive reasoning

Although there are many arguments that logic is an appropriate tool for artificial intelligence, there has been a perceived problem with the monotonicity of classical logic. This paper elaborates on the idea that reasoning should be viewed as theory formation where logic tells us the consequences of our assumptions. The two activities of predicting what is expected to be true and explaining observations are considered in a simple theory formation framework. Properties of each activity are discussed, along with a number of proposals as to what should be predicted or accepted as reasonable explanations. An architecture is proposed to combine explanation and prediction into one coherent framework. Algorithms used to implement the system as well as examples from a running implementation are given.     

Three Process Perspectives: Organizations, Teams, and People

This paper provides the author's personal views and perspectives on software process improvement. Starting with his first work on technology assessment in IBM over 20 years ago, Watts Humphrey describes the process improvement work he has been directly involved in. This includes the development of the early process assessment methods, the original design of the CMM, and the introduction of the Personal Software Process (PSP)^SM and Team Software Process (TSP){^SM}. In addition to describing the original motivation for this work, the author also reviews many of the problems he and his associates encountered and why they solved them the way they did. He also comments on the outstanding issues and likely directions for future work. Finally, this work has built on the experiences and contributions of many people. Mr. Humphrey only describes work that he was personally involved in and he names many of the key contributors. However, so many people have been involved in this work that a full list of the important participants would be impractical.     

基于复小波噪声方差显著修正的SAR图像去噪

提出了一种基于复小波域统计建模与噪声方差估计显著性修正相结合的合成孔径雷达(Synthetic Aperture Radar,SAR)图像斑点噪声滤波方法。该方法首先通过对数变换将乘性噪声模型转化为加性噪声模型,然后对变换后的图像进行双树复小波变换(Dualtree Complex Wavelet Transform,DCWT),并对复数小波系数的统计分布进行建模。在此先验分布的基础上,通过运用贝叶斯估计方法从含噪系数中恢复原始系数,达到滤除噪声的目的。实验结果表明该方法在去除噪声的同时保留了图像的细节信息,取得了很好的降噪效果。     

How do children do mathematics with LOGO?

Abstract  This paper considers some results of a study designed to investigate the kinds of mathematical activity undertaken by children (aged between 8 and 11) as they learned to program in LOGO. A model of learning modes is proposed, which attempts to describe the ways in which children used and acquired understanding of the programming/mathematical concepts involved. The remainder of the paper is concerned with discussing the validity and limitations of the model, and its implications for further research and curriculum development.     

Editorial: Special issue on recent advances in hybrid control theory and applications

正The demands of a rapidly advancing technology for faster and more accurate controllers have always had a strong influence on the progress of automatic control theory.In recent years control problems have been arising with increasing frequency in widely different areas,which cannot be addressed using conventional control techniques.The principal reason for this is the fact that a highly competitive economy is forcing systems to operate in regimes where     

Information for Authors

正Aim The Journals of Zhejiang University-SCIENCE(A/B/C)areedited by the international board of distinguished Chinese andforeign scientists,and are aimed to present the latest devel-opments and achievements in scientific research in China andoverseas to the world’s scientific circles,especially to stimulateand promote academic exchange between Chinese and for-eign scientists everywhere.     

View-based model-driven architecture for enhancing maintainability of data access services

In modern service-oriented architectures, database access is done by a special type of services, the so-called data access services (DAS). Though, particularly in data-intensive applications, using and developing DAS are very common today, the link between the DAS and their implementation, e.g. a layer of data access objects (DAOs) encapsulating the database queries, still is not sufficiently elaborated, yet. As a result, as the number of DAS grows, finding the desired DAS for reuse and/or associated documentation can become an impossible task. In this paper we focus on bridging this gap between the DAS and their implementation by presenting a view-based, model-driven data access architecture (VMDA) managing models of the DAS, DAOs and database queries in a queryable manner. Our models support tailored views of different stakeholders and are scalable with all types of DAS implementations. In this paper we show that our view-based and model driven architecture approach can enhance software development productivity and maintainability by improving DAS documentation. Moreover, our VMDA opens a wide range of applications such as evaluating DAS usage for DAS performance optimization. Furthermore, we provide tool support and illustrate the applicability of our VMDA in a large-scale case study. Finally, we quantitatively prove that our approach performs with acceptable response times.