共查询到16条相似文献,搜索用时 136 毫秒
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内容适配技术是实现通用多媒体接入的技术体系。MPEG-21标准提出了内容适配技术框架和服务环境描述技术规范。针对MPEG-21内容适配框架,从内容适配系统、服务环境数据交换、适配决策等方面,介绍国内外相关研究现状。 相似文献
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目前的内容适配技术主要从单网络单终端角度出发,未考虑当前及未来可能的网络运营模式。为解决设备能力和多媒体内容/服务不匹配问题,引入内容适配技术,提出一种面向多网多终端协同的内容适配技术。通过引入本体建模技术,将复杂的多网多终端环境化分为单网单终端、单网多终端和多网单终端3种情况,并采用逻辑决策和物理决策的两级决策方案,实现多网多终端协同的内容适配服务,从而完善单网单终端向多网多终端的过渡。应用结果表明,该内容适配模型可解决终端能力和多媒体内容/服务不匹配问题。 相似文献
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通用多媒体内容访问是未来多媒体服务的常用模式。针对这一访问模式,MPEG-21提出了DIA技术框架,以期实现相关技术标准化。但是,DIA现在只对上下文描述等元数据制定了标准,而适配决策引擎仍然是一个开放问题。针对已有适配决策模型存在的问题,提出了一种适配决策树模型,该模型将适配决策视为序列决策,并用决策树对其建模。为满足多媒体服务的个性化需求,利用用户偏好信息建立适配决策树。此外,利用优化模型构建决策空间,使参与决策的对象数缩小为模态数,从而减少了适配决策时间,满足了多媒体服务的实时性。通过仿真实验证明,该适配决策树模型在决策误差和平均迭代次数两个指标上都优于或相近于已有的适配决策模型。 相似文献
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传统网络的服务管理和供应模式静态僵化,难以从全局角度为跨域数据流制定统一的安全和调度策略,无法满足多样化的安全需求。提出一种基于服务功能链(SFC)的多域安全服务按需适配方法,利用软件定义网络(SDN)和网络功能虚拟化(NFV)等技术,通过多层接口建立统一的描述模型,配置所需的安全服务资源,实例化所需的安全服务功能,并使用服务功能链将安全服务功能组合,进而实现安全服务的按需适配。最后,通过搭建原型系统,在不同的实验场景中验证所提方法的可行性。 相似文献
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数字项适配是MPEG-21标准中一项非常重要的关键技术.本文研究MPEG-21中的数字项适配技术以及媒体独立格式的资源适配机制,实现一套基于MPEG-21 DIA的图像适配系统,提供了数字项解析、适配决策形成以及资源适配等功能.并在此基础之上试验了新的基于感兴趣区域的适配方法.试验结果表明该系统是完整和有效的,采用的新的适配方法是新颖的. 相似文献
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服务协作以服务为构造单元,通过组合不同的服务,实现复杂的业务逻辑,并以此为基础构建新的应用.为实现正确的服务协作,服务之间的交互必须是兼容且一致的.适配技术通过构造适配器来弥补服务之间的交互差异,为解决协作的一致性问题提供了有效的方法途径.然而考虑到服务计算环境的动态特性,协作适配器本身应具有动态调整及重新配置的能力,从而避免使其成为协作系统响应动态变化的可适应能力的瓶颈.文中首先给出了一种基于适配的服务协作方法,以保证服务交互的一致性.并针对提出的适配器结构,建立了适配器的执行模型,在此基础上给出了适配器的动态更新方法,使适配器具有可重配置以及动态调整的能力,从而保证了基于适配的服务协作系统的灵活性和动态可适应性. 相似文献
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Wai Yip Lum Lau F.C.M. 《IEEE transactions on pattern analysis and machine intelligence》2003,29(12):1100-1111
We address the challenges of building a good content adaptation service for mobile devices and propose a decision engine that is user-centric with QoS awareness, which can automatically negotiate for the appropriate adaptation decision to use in the synthesis of an optimal adapted version. The QoS-sensitive approach complements the lossy nature of the transcoding operations. The decision engine will look for the best trade off among various parameters in order to reduce the loss of quality in various domains. Quantitative methods are suggested to measure the QoS of the content versions in various quality domains. Based on the particular user perception and other contextual information on the client capability, the network connection, and the requested content, the proposed negotiation algorithm will determine a content version with a good aggregate score. We have built a prototype document adaptation system for PDF documents to demonstrate the viability of our approach. 相似文献
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Overlay networks are becoming widely used for content delivery because they provide effective and reliable services that are not otherwise available. However, they can negatively affect each other as well as the underlying network. A management system that controls and adapts their behavior is therefore needed. This will meet not only the specific demands of the users but also those of the network and service providers. This paper presents a novel approach to the issue of automating overlay network management. In contrast to existing management approaches which require static a priori policy configurations, policies are created dynamically. A policy layer consists of a set of policy enforcement points and policy decision points. This is used to capture the goals of users, services, and networks into network-level objectives. The behavior of the overlay network is adapted to the changing conditions in its environment. The creation, adaptation, and termination of overlays are achieved through policies. Policies are generated and enforced on the fly from the context information of the user, the network and the service provider. The new approach provides users and applications with more flexibility to dynamically change their quality-of-service requirements while maintaining smooth quality-of-service delivery. We show the advantages of our architecture and provide simulation results to verify its effectiveness. 相似文献
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《Internet Computing, IEEE》2002,6(1):73-77
The Media Accelerating Peer Services system extends P2P infrastructures to improve multimedia services across heterogeneous computing platforms. In this article, we present an architecture and resource management and adaptation framework that transcends existing infrastructures to accommodate and accelerate multimedia peer applications and services. We also propose key technology components that support seamless adaptation of resources to enhance quality of service and the building of better tools and applications that utilize the peer-computing network's underlying power 相似文献