Quality of experience evaluation of HTTP video streaming based on user interactive behaviors

User interactive behaviors play a dual role during the hypertext transfer protocol (HTTP) video service: reflection and influence. However, they are seldom taken into account in practices. To this end, this paper puts forward the user interactive behaviors, as subjective factors of quality of experience (QoE) from viewer level, to structure a comprehensive multilayer evaluation model based on classic network quality of service (QoS) and application QoS. First, dual roles of user behaviors are studied and the characteristics are extracted where the user experience is correlated with user interactive behaviors. Furthermore, we categorize QoE factors into three dimensions and build the metric system. Then we perform the subjective tests and investigate the relationships among network path quality, user behaviors, and QoE. Ultimately, we employ the back propagation neural network (BPNN) to validate our analysis and model. Through the simulation experiment of mathematical and BPNN, the dual effects of user interaction behaviors on the reflection and influence of QoE in the video stream are analyzed, and the QoE metric system and evaluation model are established.     

嵌入式MPEG-4视频流媒体服务器设计

利用GPI(通用公共授权)的开源Linux代码,介绍了嵌入式MPEG-4视频服务器的设计和研制,阐述了在嵌入式Linux平台上设计、优化设备驱动程序和视频流媒体服务器的策略。本设计采用GO7007SB作为硬件压缩芯片,使用AT91RM9200芯片作为主要控制芯片,实现了带100 MHz以太网接口的高性能网络摄像机。在约1 Mbit/s的传输率下,可以达到CCIR-601格式的视频信号的实时压缩和传输能力。     

ASP实现文件上传的方法与研究

在浏览器／服务器的应用环境中，上传各种类型的文件一直是困扰用户管理应用的难题之一。详细介绍了ASP应用协议网页中HTTP上传的3种机制，实现各种类型文件上传的原理，重点对ASP中引入特性代码RFCl867的新类型：File以及ADO Stream加入在Web应用程序中实现各种类型文件上传进行了研究，并结合实例介绍了ASP对各种类型文件上传的开发过程及实现方法。     

Cookie based online tracing method for cyberlockers resource

Cyberlockers have recently become an Internet-based agent of information dissemination. In light of the non-negligible fraction accounted by the traffic flows originating from cyberlocks, it is necessary to trace them for net-work security. An efficient and scalable cookie based online cyberlockers resource tracing method was proposed, called CookieTracing. It can achieve an efficient association between cyberlockers resource and its download redirect chain by construction of index table between cookie and HTTP sessions in massive HTTP sessions. Meanwhile, through cumula-tive hash algorithm, it can speed up the validation of tracing results. Experimental results show that this method performs good efficiency and scalability.     

嵌入式TCP/IP在播出设备上的实现

随着网络化在播出系统中的逐步深入,设备应该具有哪些必要的网络功能,而这些功能叉该如何实现？本文立足于嵌入式播出设备上网络功能的实现,着重讲述了如何在嵌入式设备上搭建TCP／IP协议栈、如何实现HTTP Server和SNMP Agent。     

浅析电信营运商信息化建设之负载均衡技术优化加速HTTP应用

负载均衡技术通过设置虚拟服务器IP（VIP）,将后端多台真实服务器的应用资源虚拟成一台高性能的应用服务器,使用负载均衡算法,将大量来自客户端的应用请求分配到后端的服务器进行处理。通过负载均衡设备提供的HTTP优化和加速功能,能够大大提升电信运营商后端服务器系统的处理能力,降低服务器端负载情况,节约服务器资源和广域网链路带宽,从而大大减少电信运营商的用户在请求访问服务时所等待响应的时间。     

移动网络中的流量加速技术

文章提出了采用多种流量加速技术,比如流量压缩和缓存技术、应用协议优化技术、区分业务和用户的带宽控制技术等,对移动数据流量进行管控、优化和疏导。多种流量加速技术的结合使用,可以减少流量增加对网络容量的冲击,提高用户体验。其中,流量压缩技术可以使得文本和图片的流量大大减少,并同时适配终端,满足移动用户的体验;流量缓存技术可以在本网内缓存热点内容,减少网间拥塞、用户访问时延及晚间的结算费用;超文本传输协议(HTTP)优化技术可以改善HTTP协议的性能,在不扩容的情况下提高移动网络的吞吐量。实验室测试和现网试点证明,上述技术和方法的应用可以取得比较好的移动数据流量管控、优化效果。     

基于SIP通信的安全性研究

本文简要说明了SIP协议内容,分析了基于SIP协议的通信网络所面临的安全威胁,通过对IETF公布的草案和标准的研究,总结并提出了一些解决SIP网络安全问题的方案。     

基于J2ME的无线邮件系统的设计和实现

目前的无线邮件服务模式主要以SMS，MMS等简单的邮件信息模拟为主，并没有使用到邮件服务的大多数功能，而且使用的方便性、操作性、功能扩展性等都不能满足应用的需求。本文分析了无线数据服务和邮件服务模式的演变，讨论了系统整体方案的选择，提出了基于J2ME的系统解决方案；详细讨论了系统的设计与实现，制定了HBWMP通讯协议。     

Web Server Performance Modeling

The advent of Web technology has made Web servers core elements of future communication networks. Although the amount of traffic that Web servers must handle has grown explosively during the last decade, the performance limitations and the proper tuning of Web servers are still not well understood. In this paper we present an end-to-end queueing model for the performance of Web servers, encompassing the impacts of client workload characteristics, server harware/software configuration, communication protocols, and interconnect topologies. The model has been implemented in a simulation tool, and performance predictions based on the model are shown to match very well with the performance of a Web server in a test lab environment. The simulation tool forms an excellent basis for development of a Decision Support System for the configuration tuning and sizing of Web servers.