基于TOE技术的硬线TCP/IP协议栈设计

本文介绍了当今互联网的发展和TOE技术,介绍了TCP/IP协议栈的原理,提出了TCP/IP协议栈芯片的设计.在设计中,实现了剪裁了的TCP/IP协议栈,主要实现了TCP协议、UDP协议、IP协议、ARP协议和ICMP协议.     

基于FTP协议的隐蔽通道的研究与实现

利用协议的漏洞构建隐蔽通道逐渐成为网络攻击的一种重要手段.目前的研究大都是在传输层和网络层协议上构建隐蔽通道,如基于TCP、IP或者ICMP协议等.     

客户服务器通讯软件的Winsock设计与实现

1、TCP/IP通讯协议及开发概述 TCP/IP协议使用IP地址作为网络中计算机的标识,而且每台计算机的IP地址都是唯一的,一般情况下,每台计算机运行的程序不止一个,因此要在应用程序中建立连接的话,还需要一个地址标识。在TCP/IP协议中使用端口(Port)作为计算机上运行应用程序的标识,因此TCP/IP协议中一个有效的网络地址包括IP地址和端口地址。 TCP/IP协议提供的计算机之间的通讯方式有两种:TCP方式和UDP方式。 Visual Basic6.O中提供了Winsock控件,用于支持网络中两台以上计算机之间进行通信。Winsock 控件提供了多样化的属性和方法来实现网络通信。通过设置Winsock控件属性及调用控件方法就能够实现TCP或UDP方式的网络通信。利用这个控件,编程人员可以较轻松地编写出TCP/IP客户服务器程序。     

基于流媒体技术的在线视频课件的设计与实现

流媒体技术是利用TCP协议和UDP协议之间的差别,在通信双方之间使用HTTP/TCP来传输联络信息,通过RTP/UDP协议传输多媒体文件的内容。这一工作方式极大地提高了多媒体教学资源在网络上的传输速度。基于流媒体技术的在线视频课件的设计与实现方法,包括流媒体教学课件的制作以及课件的点播实现。这种设计和实现具有交互性、易于向其它硬件平台移植、易于维护、投入少等特点,适合开发视频应用,对实现高效在线学习具有重要的现实意义。     

基于windows平台的网络嗅探器系统的设计与实现

网络嗅探和分析技术是很多网络安全软件实现的基础,也是设计网络分析软件的基础,现存在的一些技术如防火墙、协议分析等软件的实现的前提都是以数据包的嗅探捕获,所以研究相关的数据包嗅探和分析技术对保证网络的安全运行是十分必要的。该项目实现了数据包嗅探分析器。程序中网络监听的目标TCP/IP协议中的ARP、IP、TCP、UDP四种协议,基于Windows操作系统为平台,在数据链路层捕获原始数据包,并从中提取出网络通信协议及数据包的数据。     

基于DHCP SNOOPING的DHCP网络部署

在公司或企业内部网络中,为了更好的管理用户的IP地址分配,通常让用户自动获取IP地址。这种技术就称为动态的主机计算机分配协议,传输层协议使用UDP,用来给lan网络的用户分配IP地址。DHCP因为IP地址管理的方便而被广泛采用。     

Windows下基于SPI的网络数据包拦截的设计与实现

基于TCP、UDP协议的网络应用程序如果在内部对代码段进行检查或修复系统挂钩,通过HOOK API截包技术基本失效,在这种情况下,使用WINSOCK2SPI技术就完全胜任对特定网络应用程序数据包的拦截任务,而且实现简单效率高,可移植性强。     

Linux环境下基于Socket的网络通信

随着Linux操作系统的不断推广,Linux环境下的Socket开发和研究已成为人们关注的热点。Socket既适用于同一台计算机上的进程间通信,也适用于网络环境中的进程间通信。它已成为当前许多操作系统的网络API,也是网络操作系统中必不可少的基础功能。因特网为网络中的应用提供了两种类型的服务:由TCP协议提供的面向连接服务和由UDP协议提供的无连接服务。     

基于UDP协议的网络通信在VxWorks操作系统中的实现

介绍了VxWorks下UDP协议的实现方法,详细分析了UDP socket接口函数及其使用方法,给出了基于UDP协议的网络通信的编程示例代码。     

基于多通道虚拟现实环境的应用开发研究

研究了基于多通道虚拟现实环境的网络通讯模块实现方法,以及复制式网络模型下的应用开发方法,并给出了三维城市地质信息系统的具体应用实例。网络通讯模块采用面向对象（OO）技术对TCP、UDP协议进行封装,以消息形式通过网络传输客户端与服务器端的交互信息。应用程序框架采用虚拟现实插件技术实现功能的即插即用。     

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.     

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.     

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.     

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.     

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.     

Rough Justice: A Statistical Assessment of ICANN's Uniform Dispute Resolution Policy

Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP.     

Prevalence of soft neurological signs in Chinese people

Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.     

Monoculture Rubber Plantations Have Negative Ef ects on Controlling Splash Erosion

<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence     

Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels

<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese     

More than Skin Deep – Understand Skin Biology by Means of Dermatogenomics

<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages.