IMS-Based IPTV架构探讨

IPTV是一项新的,极具潜力的商业模式。它以用户为中心,支持与用户的互动并提供个性化的广播业务。但如何向异构网络中的每一个用户提供IPTV业务并对其进行有效的管理成为该业务能否被普遍推广的关键。因此,我们引入IP多媒体子系统(IMS)负责管理和控制基于IP网络的多媒体会话。我们分析了IPTV的具体业务流程,提出了基于IMS的IPTV架构并给出了必要的评估。     

基于IMS的PoC业务仿真系统的设计与实现

IMS是第三代移动通信伙伴提出的支持IP多媒体业务的子系统。IMS具有接入无关性以及标准开放的业务控制接口等特点。IMS提供了业务融合的基础,它基于IP技术同时支持语音、数据和多媒体业务等。IMS提供了业务融合的基础,它基于IP技术同时支持语音、数据和多媒体业务等。PoC业务是在IMS上实现的一种即时通信业务,其简单方便,通信快捷、即按即说、群组通话的特点使其成为移动增值业最有前景的应用之一。本文描述了一个基于IMS的PoC业务仿真系统的设计与实现。本文首先介绍了IMS、SIP和PoC业务等相关背景知识,然后提出一种设计与实现方案。     

基于策略的IMS状态感知通信业务技术及实现

随着计算机和网络技术的不断演进,3GPP提出了IMS(IP多媒体子系统)以支持在UMTS系统中支持包交换域中多媒体业务的一个核心子系统。通过扩展IMS系统以支持状态感知通信业务,可以提升系统的业务提供能力,从而提供新的投资回报。给出了IMS系统中,一种基于网络环境上下文感知的策略管理架构,以支持IMS用户业务体验不受环境变化的干扰,并给出了IMS系统中,基于策略的状态感知通信业务的具体实现方法以及其中使用的一些关键技术。     

IMS网络架构中SIP协议及SDP协议的研究分析

本文分别从IMS网络的整体架构和IMS网络业务体系结构两个角度分析了IMS的网络架构,并深入分析了用于创建会话的SIP协议,以及与SIP协议密切相关的用来描述会话信息的SDP协议的消息格式、方法等内容,并对IMS网络架构下的SIP协议简要分析。     

基于云服务的IMS系统控制与管理

由NIST定义云计算是实现快速配置的计算资源(如网络,服务器,存储,应用程序和服务)的共享,按最少网络访问的模式为客户提供交互释放的管理服务。IP多媒体子系统(IMS)是标准化的体系结构,本文的重点确定基于云服务的IMS系统控制与管理的标准化要求,以确保IMS系统互操作性以及基于云服务的简化性,同时系统应支持监管,Qo S和容量要求。     

基于C＋＋的SIP协议解析模块的设计

会话初始协议是IETF提出的一种IP多媒体会话协议,是下一代网络和IP多媒体子系统的关键协议。首先简要介绍了SIP的基本内容和消息格式。在对比其他SIP协议解析系统的基础上,结合继承、多态的特点,提出了一种按行解析SIP消息的方法,最终使用该方法在Visual C＋＋6．0环境下实现了SIP消息的解析。     

基于SIP协议的应用

作为下一代网络和IP多媒体子系统的重要协议,SIP协议的主要目的是在IP网络中建立、修改和终止多媒体会话,本文主要针对关于SIP协议在电话网络中的主叫用户和被叫用户之间建立通话的应用进行阐述。     

基于IMS融合网中传统因特网的QOS研究

IP多媒体子系统(IMS)旨在集成移动通信与Internet技术,从而将Internet服务的强大性能及丰富资源带入移动环境,它也被看作是未来网络融合的解决方案.     

LTE语音技术及VoLTE技术专利分析

正研究内容VoLTE即Voice over LTE,它是一种基于LTE和IMS的IP数据传输技术,能够在LTE网络上把语音与数据业务进行独立承载,并且以支持多样性的多媒体业务以及多种接入的IMS语音业务为基础。由于VoLTE可向用户提供更高质量、更低时延的服务,因此VoLTE技术作为LTE中快速发展的技术,需要持续对其发展进行跟踪,分析,提前     

IMS2.0业务架构研究

探讨IP多媒体子系统（IMS：IP Multimedia Subsystem）和Web2．0世界的融合的好处。为了达到这个目的,提出了IMS2．0业务体系的概念。IMS2．0的业务体系的目标是将IMS和Web2．0结合起来．也就是对Web2．0开放IMS特性,同时在IMS中采用Web2．0的一些规则．给用户提供一个有利于融合应用业务开展的环境。     

Low doses of a red wine ingredient figh diabetes in mice

Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said.     

Students' Reactions to the Introduction of Videoconferencing for Classroom Instruction

This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors.     

Molecular motor assembly of a biomimetic system

Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction.     

Cooler temperatures inductive to locust outbreaks

Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007.     

To serve and promote science development via innovation

CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing.     

Exploring Multiplexity: Social Network Structures in a Computer-Supported Distance Learning Class

A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction.     

Tracing the origin and early radiation of birds——Paleornithologist ZHOU Zhonghe

With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants."     

The Role of Intermediating Institutions in the Diffusion of Electronic Data Interchange (EDI): How Industry Associations Intervened in Denmark, Finland, and Hong Kong

Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies.     

The Information Environment and Universal Service

This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment.     

How Electronic Publishers are Protecting Against Piracy: Doubts About Technical Systems of Protection

The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means.