Design of a video conference system supporting Multicast based on SIP

下一代网络（NGN）是一种综合、开发的网络，提供包括话音、数据和多媒体等业务。它不是现有电信网和IP网的简单延伸和叠加，而是两者融合而成的结果；NGN的出现与发展是在继承现有网络优势的基础上实现的平滑过渡。 SIP协议作为NGN中多媒体通信的核心协议，以其简单、灵活和不错的扩展性和开放性而得到业内的普遍关注和青睐。随着宽带多媒体网络的不断发展，IPTV、视频会议、数据和资料分发、网络音频应用、网络视频应用、多媒体远程教育等宽带网络应用层出不穷，采用单播技术构建的传统网络，已经无法满足新兴宽带网络应用在带宽和网络服务质量方面的要求，随之而来的是网络延时、数据丢失等问题。此时通过引入IP组播技术...Next Generation Network (NGN) is an integrated and open network,which supports voice,data and multimedia services.It is not a simple extension of IP networks and overlay of the existing telecommunications network,but the integration of the two.The emergence and development of NGN are in succession of the existing network advantages to realize a smooth transition. Session Initiation Protocol (SIP)...学位：工学硕士院系专业：信息科学与技术学院通信工程系_通信与信息系统学号：2332007115219

自然保护区群网生态建设的几点思考

论述了自然保护区在生态建设中的作用、我国国家级自然保护区的分布、福建国家级自然保护区的类型及其分布,提出了自然保护区群网建设的必要性.针对保护区建设的现状,提出了现阶段的工作重点:⑴建立自然保护区之间的群网关系;⑵开展自然保护区群网建设与研究工作;⑶保护区群网建设与森林涵养水源的重大意义和保护区域水的生态安全和生态效益;⑷保护区群网建设与发展循环经济;⑸主导资源保护与合理利用;⑹统一落实经费筹措;⑺加强部门、人员协调;⑻配合生态省建设工作·从而促进自然保护区的生态保护、生态修复和生态工程的协调发展

The research of micro-electrolysis process composed of discarded iron slag and coke pretreating landfill leachate

［中文文摘］研究表明,废铁屑和焦炭微电解是预处理垃圾渗滤液的一种有效方法,可去除垃圾渗滤液COD、色度和腐殖酸等污染物质,改善其可生化性、降低负荷,为后续生化处理创造良好的条件。通过静态正交实验确定废铁屑和焦炭最佳投加体积比为1∶3;最佳反应pH值为4;动态实验中,反应时间为1 h时,COD和色度去除率分别高达68%和91%;BOD/COD从0.3提高到0.5左右。［英文文摘］The study shows that micro-electrolysis process is an effective method to pretreat landfill leachate.It can remove much of COD,chroma,humic acid and can improve leachate′s biodegradable ability to create good conditions for following biochemical treatment.The optimal volume ratio of iron slag and coke is(1∶3) by orthogonal array experiments;the optimum pH is 4.In continuous feed experiments,the removal rates of COD and chroma could reach 68% and 91% respectively;BOD/COD is increased from 0.3 to about 0.5

Adaptive live VM migration over WAN: modelingand implementation

The combination of traditional process migration and the new virtualization technology enables mobility of virtual machines and resource provisioning within data centers. While applied to wide area network (WAN), a traditional migration algorithm has to adjust itself according to the various WAN situations and VM status. This thesis identifies four performance measurements of a VM migration: total migration time, downtime, remote up time and performance degradation. It observes that the total migration time and the remote up time of traditional pre-copy over WAN is too long to tolerate. This thesis claims that even for WAN, post-copy could be used to improve the total migration time and remote up time, only by introducing tolerable, predictable and controllable performance degradation. The adaptiveness of the migration algorithm is concerned. It proposes a hybrid solution of pre-copy and post-copy, both for memory and storage, to do the migration. In the hybrid solution, a fraction of memory (Mfrac) and a fraction of storage (Sfrac) are migrated in the pre-copy and freeze-and-copy phase, and the remaining are migrated in the post-copy phase. A model-based solution with the help of profiling is proposed to adaptively find the best combination of Mfrac and Sfrac. The evaluation part suggests that the proposed solution could adapt to different application behaviors and network conditions.published_or_final_versionComputer ScienceMasterMaster of Philosoph

Design of a PTT Server Model on SIP Supporting Multicast

PTT业务是近年来研究的一个热点,它将逐步成为人们生产、生活不可缺少的部分。本文结合现代通信技术的发展趋势,提出和设计了基于PC机和IP多播通信方式的PTT服务器方案,并将SIP协议作为呼叫控制信令,其中着重研究了IgMP多播协议在通信传输中的应用。PTT is a research hotspot in recent years,which will be an indispensable part in our work and life.This paper,combining with the development of communication technology,puts forward and designs PTT server project based on PC computer and IP multicast,in which the application of IGMP Protocol in network communication transmission is studied emphatically with the SIP as the call control signaling

聚乙二醇修饰牛血清白蛋白的反应与分析

采用N ,N′ 羰基二咪唑活化法活化单甲氧基聚乙二醇 5 0 0 0分子一端的羟基 ,对活化后的单甲氧基聚乙二醇分子进行了元素分析。用该活化产物对牛血清白蛋白的赖氨酸侧链氨基进行化学修饰。应用毛细管电泳对聚乙二醇修饰后的产物进行了分析 ,并与高效液相色谱分析结果作了对照研究 ,表明毛细管电泳对修饰后的牛血清白蛋白有更好的分析效

Indoor mobile robot of restructural navigation performance test and appraisal appearance

本实用新型涉及一种可重构室内移动机器人导航性能测评仪，包括定位传感器、摄影测量系统、计算机、移动机器人以及设置于移动机器人上的测量标靶；所述定位传感器和摄影测量系统均与计算机连接；所述定位传感器设置于测试环境上方或侧面。本实用新型中多台定位传感器可进行重新组合适应不同面积大小的测试环境，适用于体积大、中、小型号的室内移动机器人导航性能测试

一种便携式室内移动机器人导航性能测评系统及方法

本发明涉及一种便携式室内移动机器人导航性能测评系统及方法，测量桁架固定于被测移动机器人上，且在测量桁架上设置测量靶标；在移动机器人上方或侧方设置定位传感器；上位机通过信号线缆连接摄影测量系统和定位传感器，接收摄影测量系统和定位传感器发送的反射靶位置信息，根据接收到的位置信息获得被测移动机器人的航迹和航向。本发明涉及室内移动机器人导航性能评测，用于定量的评价室内小型机器人导航性能指标，为导航系统的设计、改进和完善提供科学依据，促进移动机器人自主导航技术的创新与进步