AVS拉开联盟序幕

本刊讯记者王占波报道5月25日,我国第一个数字音视频编解码技术标准(AVS)产业联盟正式成立。华为、中兴、浪潮、中关村高新技术产业协会等十二家国内企事业单位共同发起成立AVS产业联盟,联手打造中国的音视频标准。该标准一旦推广应用,将有利于增加我国企业在国际舞台的话语权。AVS产业联盟希望逐步把国内的音视频产业集团组织起来,形成完整的产业链,共同占领国际市场。会上,AVS产业联盟秘书长张伟民指出,AVS产业联盟的成立预示着AVS产业化的序幕已揭开,我国AVS产业化将进入一个新的发展时期。他表示,数字音视频编解码标准是数字电…     

AVS视频和音频编码标准的应用

AVS标准是《信息技术：先进音视频编码》系列标准的简称，AVS标准包括系统、视频、音频、数字版权管理等四个主要技术标准和一致性测试等支撑标准，是我国具备自主知识产权的第二代信源编码标准。本文简要探讨AVS标准概况，下期刊登《AVS—S音视频监控标准介绍与展望》，期望读者继续关注。     

AVS视频编码标准技术回顾及最新进展

AVS(audio video coding standard)工作组是“数字音视频编解码技术标准”工作组的简称,由国家原信息产业部科学技术司于2002年6月批准成立.工作组的任务是制(修)订数字音视频的压缩、解压缩、处理和表示等共性技术标准,为数字音视频设备与系统提供高效经济的编解码技术.经过10多年的努力,AVS已经成功制定一系列标准,如AVS1,AVS+和AVS2.其中AVS1和AVS2的说法源于AVS第1阶段和第2阶段的工作或第1代、第2代标准.AVS+是工作组专门为高清数字电视广播制定的一个标准.目前AVS1和AVS+标准已经制定完成并成功应用于许多行业中,AVS2也即将完成.将对AVS的AVS视频标准12年来的技术发展过程给以概述,并简单介绍目前最新一代视频编码标准AVS2关键技术,最后对视频编码技术的未来发展方向予以展望.     

基于AVS的嵌入式音视频同步方法

音视频同步是数字电视广播和多媒体通信等应用的关键技术。该文提出一种基于AVS并结合嵌入技术的音视频同步方法。将压缩音频数据嵌入AVS视频编码系统,保证传输或存储、接收端解码与播放过程中的音视频始终同步。实验结果表明,该方法实现了音视频完全同步,能减小用于同步的开销。     

AVSA：抢夺“视听”话语权

AVS（Audio Video coding Standard）标准,是中国具有自主知识产权的音视频编解码标准。 自2002年6月数字音视频编解码技术标准工作组成立以来,AVS标准获得各界的广泛关注与支持,并逐渐形成比较完备的知识产权管理体系和组织。     

一种基于AVS卫星数字视频系统的实现

2002年中国开始制定了新一代数字音视频编解码标准———AVS。由于它采纳了近几年来国内研究的先进音视频编码技术,其不仅与H.264/AVS相比,具有较低的复杂度,并可通过一站式授权方式支付少量费用来获得AVS使用权,因此可作为中国卫星电视直接入户方案的一种较好,且具有竞争力的候选标准。在对AVS和MPEG-2的差异进行比较的基础上,分析了两种在传输系统中替代MPEG-2的方法:直接AVS编码和AVS转码,并给出了一种转码方案,最终实现了新一代基于AVS卫星视频广播系统。     

基于AVS的软硬件协同可变长码解码器设计

提出一种基于软硬件协同方法的AVS可变长码解码器结构设计.定长码、指数哥伦布码及AVS视频标准特有的基于内容自适应二维可变长码(CA-2D-VLC)均可在该解码器上实现正确解析.通过对19张可变长码表的优化整合,提出一种新的码表设计方法.经验证,新码表相较使用原始码表可将硬件消耗降低30%以上.为确保整个系统设计的合理性和正确性,以RM52J为蓝本编写针对本解码器的验证器,通过对92个一致性测试码流序列解析对比,表明本设计满足AVS视频解码要求.     

AVS标准中的视频编码关键技术研究

AVS是中国自主制定的数字音视频编码系列标准,主要研究了AVS-P2和AVS-P7中的关键技术,并与国际上最新视频压缩标准H.264/AVC中的关键技术进行对比分析.最后介绍了AVS工作组的最新进展,分析了AVS的产业化现状和应用前景.     

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。     

数字音视频加速行

除了在移动多点视频通讯方面的技术优势,AVS在知识产权方面和专利的方面的优势谁都无法替代。由数字音视频编码技术标准工作组(简称AVS工作组)主办,信息产业部、广电总局、中科院等单位支持的“AVS标准五周年成果展暨数字音视频产业投融资峰会”3月18日在北京香山饭店举行。此次会议有来自150多家企业机构的200多位产业高层,涵盖家电、IT、广电、电信、音响等领域的芯片、软件、系统、整机、媒体运营等整个数字音视频产业群。     

Analysis and control of a nonlinear boiler-turbine unit

A distance measure is proposed via the gap metric in this paper, and the concept is applied to a boiler-turbine unit to analyze its dynamics. It is shown that the unit shows severe nonlinearity, but the nonlinearity can be avoided by careful choice of the operating range. A single linear controller can be designed to work in such an operating range. It is also shown that the controller constraint is another source of the nonlinearity, which can be compensated using anti-windup techniques. Simulation results are given to verify the conclusions.     

Formal specification and design time testing

It is shown how design time testing can be used in conjunction with formal specification. Emphasis is placed on the benefits of using an executable specification language OBJ, of having a design controlled by requirements specification, and of adherence to the regularity and uniformity hypotheses in dynamic validation. It is shown that such an approach offers positive benefits by providing early design validation and a controlled, disciplined design process     

航空货运装载问题算法设计与研究

用回溯算法解决飞机货舱装载问题。根据货物和舱位情况,使货舱的空间和载量利用最大化。对于航空货物体积小重量轻的特点,给出一种改进算法,通过理论分析,这些方法可以有效解决该问题。     

Decision support for marketing research and corporate planning

Marketing research and corporate planning are enhanced by an effective decision support system. A system developed and implemented in an insurance company is used to illustrate how computer cartography and statistical procedures can be combined as powerful analytical tools. It also demonstrates how a nonprocedural language (SAS with SASGRAPH) can be used to create modules of systems that are efficiently implemented and easily maintained by analysts with limited programming capabilities.     

Microcomputer-assisted identification of bacteria and multicriteria decision models

A general decision analysis framework for identification of bacteria is made conspicuous. The classic identification models—binary decision tree and conditional probability models—are then enlightened in this framework and shown to be particular cases of multiattribute value function models. It is then suggested that the multicriteria collective choice rule approach can also be applied. This is illustrated by means of an experiment performed on the API commercial set of biochemical tests (identification of Enterobacteriaceae) with an ELECTRE-type model. It appears that the simultaneous use of conditional probability and ELECTRE models can improve the quality of identification. As they can be easily programmed on a microcomputer, these models are ipso facto a valuable aid to microbiologists.     

A virtual factory based approach to on-line simulation and scheduling for an FMS and a case study

The recent years have witnessed a revolution in computing capabilities. At the same time, modern manufacturing systems are becoming increasingly complex and capital-intensive. Here, we propose a virtual factory wherein an efficient prototyping testbed will be provided. It will be possible to develop detailed models to support system design and operation, to test different system configurations. Besides, It will be possible to manipulate all system features which impact performance, and to see the results of these manipulations, all without disrupting the actual system. This paper is one among very few that tries to represent the virtual factory in an analytic form so that many existing mathematical analyses can be applied. New pseudo resources can be added to form a new virtual environment, and control policy designed by engineers will be evaluated before being issued. Since a state-transition sequence of the virtual factory from the initial state to the final state can be seen as a schedule of the modeled system. An effective schedule of the processing can be obtained by using an A* based search algorithm, namely, Limited-Expansion A algorithm.     

无嫉妒蛋糕分配中的谎言

对于给定的任意一个蛋糕分配算法,研究了玩家能从谎报中获取多大的利益。考虑两种类型的玩家：风险寻求玩家和风险厌恶玩家,并且把玩家的价值密度函数限制为分段常数。证明了风险寻求玩家和风险厌恶玩家均不能从谎报中获取更多利益。但如果只允许算法在蛋糕上切[n-1]刀,证明了玩家通过谎报能够拿到多出[Θ(n)]倍的利益。     

西门子S7-1200的设计与应用 第9讲 S7-1200与IFIX在变频器监控中的应用

OPC是随过程控制的发展产生的一种工业标准,它既可以用于将现场PLC设备的数据采集到DCS或SCADA中来,也可以用于将数据从一种DCS或SCADA系统采集到另一种DCS系统、SCADA系统或其他上位应用程序中。S7-1200作为优秀的下位机PLC,它可以通过OPC技术与IFIX等优秀组态软件进行数据通信。本案例主要介绍了S7-1200与IFIX在变频器监控中的应用。     

Reducibility and unobservability of Markov processes: the linearsystem case

A vector Markov process will be called stochastically unobservable by the measurement process if there exists an initial distribution such that some marginal conditional distributions equal the corresponding unconditional ones. It will be called reducible if there exists an invertible transformation such that the transformed process is stochastically unobservable. Necessary and sufficient conditions are derived in the context of linear diffusions. It is also shown that reducibility can be regarded as a natural extension of the concept of estimability, defined for linear stochastic systems