支持多媒体传输的QoS自适应控制理论及评价模型

QoS adaptive control is one of the critcal technologies supporting the quality of service of multimedia transport.This paper puts forward an evaluation model of QoS adaptive control to support the multimedia transport.In holds out a QoS adaptive control model based on the theory of adaptive control,and gives the formal evaluation parameters system.Our contributions are the following:(1) We analyzed the Qos adaptive control based on the control theory,and it can give the theoretically instruction for ruture development.(2)We bring forward an evaluation model of QoS adaptive control mechanisms for the first time.The model provides a tool for evaluating the performance of so many kinds of QoS adaptive algorthms and mechanisms.     

高速网络多媒体传输中自适应QoS保证问题

1.引言自适应QoS技术是随着Internet中多媒体应用需求的不断增加和网络资源的限制而提出和不断发展的。何谓自适应QoS?它可定义为:“在网络资源有限的条件下,以最小的代价,在网络状态变化时,能最大限度满足用户对网络资源的需求,并获得最优的服务质量保证。”自适应QoS包括多媒体音/视频流的QoS保证、无线网络QoS保证、自适应路由、Inter-net代理服务器缓冲自适应等多个方面。国内外提出了众多自适应QoS的理论和模型,如文[1]设计了基于计算机微环境的CPU、网络接口的动态QoS管理模型AQUA,提出了集成一体化QoS管理的思想;文[2]开发了一种综合QoS管理模型,在端系统和网络中提供端到端的全程QoS保证;文[3]是RSVP的设计者LiXia Zhang提出的基于DiffServ模型的分层QoS管理模型,将自适应QoS的思想引入IP QoS领域。我们认为,总体来说当前的研究成果大都只涉及到静态的QoS调整,而QoS自适应应当集中考虑动态的资源变动方案,同时,应当在适应策略上适当考虑多种因素,如优先级、丢失率、媒体特性等。本文论述自适应QoS策略的产生和发展     

多媒体编排软件中复合文档的编辑

多种媒体类型数据组成的复合文档在编排软件中的编辑是设计开发编排软件时所要考虑的基本问题.本文提出了在空间域和时间域上实现多媒体数据编辑的策略,实现了OLE2技术在多媒体编排软件中的应用,满足了多媒体数据在呈现空间的编辑需要.     

基于ASP的多媒体文档数据库管理系统研究与实现

本文首先对ASP的相关技术进行了讨论,然后提出了一个基于ASP的多媒体文档数据库管理系统的三层B/S开放式文档体系结构。在此基础上,设计和实现了一个多媒体文档数据库管理系统。实践证明该系统技术先进、功能完善、可靠性和适应性强。     

一种类ODA的多媒体文档结构模型

ＩＳＯ的办公文档结构ＯＤＡ较好地解决了传统的文档结构定义问题，但是多媒体文档还必须增加一项新需求。文中给出一种描述多媒体文档结构的类ＯＤＡ模型，并着理讨论逻辑结构和样式结构的表示方法。     

基于无线网络GIS自适应传输模型研究

GIS空间数据传输与存储技术正在经历从有线到无线的发展过程。针对无线网络环境下存在的网络带宽不高、频繁断接、资源有限等不足带来的GIS空间数据传输效率降低问题,论述了无线网络环境下空间信息数据传输的具体方法,根据无线GIS技术特点,通过分析自适应理论和无线传输特征模型,设计了基于无线网络的自适应空间数据传输模型,探讨了自适应传输的最优化原则,并通过具体试验验证了该方法的可行性和有效性。     

实时视频流自适应速率传输策略

本文提出了一种实时视频流自适应速率传输策略ARTS,该策略通过丢包率和网络传输延迟抖动两种参数对发送端输出速率进行动态调整,以迭到拥塞控制的目的。实验证明,ARTS是TCP友好的,能够降低丢包率,有效地减少了客户端图像质量的震荡幅度,保持了网络带宽的高使用率。     

用DirectShow实现多媒体数据网络传输

多媒体数据的网络实时传输是多媒体技术的热点和难点。本文介绍了一种基于DirectShow的多媒体数据网络传输方法的实现思路，并介绍了在VC平台下网络发送Filter和网络接收Filter的具体实现过程及其实现效果。     

多媒体复合同步模型

多媒体同步是多媒体研究应用的一个重要方面,文中在分析了多媒体制作,播放的特点后,提出了一种新的多媒体的同频模型－复合同步模型。     

局域网上多媒体传输系统的实现

本文分析了多媒体信息和局域风的特点，对多媒体信息在局域网内传输的局限性和可行性进行了详细的理论研究，我们利用当前一些先进的软件技术，提出了克服这些局限性的方法，实现了多媒体信息在局域网中传输的实时性、连续性和交互性。此外，我们选择了一个具有代表性的设计环境，实现了避域网内语音多媒体信息传输系统。     

多媒体数据传输的一种自适应拥塞控制算法

该文根据多媒体数据流的特点,给出自适应参数可调的二项式拥塞控制算法ARP-BCCA(AdaptiveRegulableParameter-BinomialCongestionControlAlgorithms),ARP-BCCA算法具有TCP的兼容性,并且具有较好的自适应性和稳定性,较有利于多媒体数据的传输。     

Adaptive Multimedia Presentation Strategies

Multimedia presentations comprise various media objects such as text, audio, image, and video that are delivered to users according to certain temporal relationships. In stored multimedia presentations, these temporal relationships are explicitly formulated by the author(s) and stored along with the presentations. However, it is difficult to ensure that these temporal relationships are always strictly preserved in real-time, distributed multimedia presentations. This is due to the fact that various components of the run-time environment such as operating system and network may offer only best effort services, i.e., they may not be able to provide any real-time guarantees. In this paper, we survey the different approaches that can be used for adapting multimedia presentations to handle instances where temporal relationships cannot be preserved in a strict manner. We classify these approaches into three categories and discuss when these categories of adaptations can be used.     

基于自适应QoS保证的多媒体监控系统模型研究

分析分多媒体监控特点,认为多媒体流的QoS保证是一个重要的研究课题。提出了支持自适应QoS保证的嵌入式IP网络多媒体监控系统模型。QoS保证方案包括系统资源监测,网络带宽的预估计,借助PID算法实现多媒体自适应流的自调节,以及音频优先保证。实验表明,该模型结构简单,制定的QoS控制策略能够实时地对视音频参数进行动态调整,资源利用率高,图像传输流畅。     

分布式多媒体系统中多媒体对象交换管理器的设计与实现

给出了分布式多媒体系统中多媒体对象交换管理模块的设计及实现的方法,并详细讨论了多媒体对象交换管理模块和结构模型中的其它模块之间的相互作用关系。     

多媒体实时传输协议RTP

文章分析了现有网络协议支持多媒体通信存在的问题,介绍了实时传输协议ＲＴＰ的概念和功能,对多媒体传输的支持以及实现等技术。     

Adaptive Management of QoS Requirements for Wireless Multimedia Communications

We present a control model, which provides response time and bandwidth requirement adaptation in audio, video, and application sharing multipoint IP teleconferences for emerging wireless multimedia communications. The model is based on revealing feedback controls for multimedia call preparation and subsequent real time connection control. Case-based reasoning memory is used to associate real time congestion (connection) controls with call preparation controls and user QoS profiles. Web agents are used to capture user and application multimedia call profiles observed at the application layer and transfer them into the case memory. RTP statistics are used to identify the connection management feedback controls for the network layer. Real-time adaptation at the network layer and above is made possible by using hierarchical coding techniques. The proposed adaptive management architecture is illustrated by a case memory representation of call preparation feedback controls, RTP feedback control tests for providing audio stream bandwidth adaptation, and configuration of integrated experiments.     

一种复合型自适应盲水印算法

提出同时嵌入鲁棒水印和脆弱水印的复合型自适应盲水印算法。鲁棒水印根据邻居特征平均值和奇偶判决法嵌入到所选择的频带中,再将水印图像分块,把分块图像的灰度均值映射为混沌初值,经过若干次迭代生成脆弱水印,嵌入到其像素灰度值的LSB平面。实验结果表明,该算法对一般的图像处理具有良好的鲁棒性,同时还能对图像篡改进行精确定位,且作为盲水印算法有良好的安全性。     

An Extended Relational Data Model for Multimedia DBMSs

We have extended the canonical relational data model to enable the management of multimedia objects. In an attempt to provide a smooth paradigm shift to multimedia information system development, we have enhanced the relational data model framework with techniques for modeling, storing and manipulating multimedia data. In particular, we have provided a graphical conceptual model for structuring a multimedia document and mapping rules for translating it into an extended relational data schema. Extensions have regarded the management of foreign keys, active components, mechanisms for the management of spatial and temporal relations, and finally functions for handling multimedia presentations. As a consequence, we have also provided extensions to the SQL language to handle these new mechanisms.     

多媒体共享教学系统的开发模型与实现

提出了一种基于计算机网络、智能中央控制设备，实现控制中心和教室多级协同控制的多媒体共享教学系统的方案。介绍了多媒体共享教学系统的工作原理，并进一步给出了系统的开发模型与实现方法，该系统是一种新颖的多媒体教室方案。     

An Approach to Quality of Service Management in Distributed Multimedia Application: Design and an Implementation

Most work related to quality of service (QoS) is concerned with individual system components, such as the operating system or the network. However, to support distributed multimedia applications, the entire distributed system must participate in providing the guaranteed performance levels. In recognition of this, a number of QoS architectures have been proposed to provide QoS guarantees. The mechanisms and schemes proposed by those architectures are used in a rather static manner since the involved entities, e.g., the network, sender and receiver, are known before the connection (call) set-up phase. In contrast to these architectures, we propose a general QoS management framework which supports the dynamic choice of a configuration of system components to support the QoS requirements for the user of a specific application. We consider different possible system configurations and select the most appropriate one depending on the desired QoS and the available resources. In this paper we present an overview of this general framework; especially, we concentrate on QoS negotiation and adaptation mechanisms. To show the feasibility of this approach, we designed and implemented a QoS manager for distributed multimedia presentational applications, such as news-on-demand. The negotiation and adaptation mechanisms which are supported by the QoS manager are specializations of the general framework. The proposed framework allows to improve the utilization of system resources, and thus to increase the system availability; it also allows to recover automatically, if this is possible, from QoS degradations. Furthermore, it provides the flexibility to incorporate different resource reservation schemes and scheduling policies, and to accommodate new system component technologies.