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1.
本文从IPV6的作用出发即解决IPV4地址枯竭问题,讲述了基于IPV6的两种动态路由协议RIPng和OSPFV3,结合思科的网络模拟软件Packet Tracer完成三个教学实例,在设备有限的条件下达到了良好的教学效果,同时为今后的教学实例提出一些新的思路。 相似文献
2.
无线传感网络通常是以无线传感节点的能量和信号传输路径的关系构建路由协议的。传统的LEACH协议没有考虑无线传感网络中存在多嵌入不兼容通信设备的问题,一旦网络中存在大量嵌入不兼容传感节点,则这些节点的属性就会偏离普通节点,将会导致无线传感网络通信性能降低。为此,提出考虑多嵌入不兼容设备的无线传感网络路由优化设计方法。在传统的LEACH路由协议的基础上进行优化设计,以传感节点剩余能量作为衡量指标选取合理的节点作为路由节点,并进行均匀布置。在信息传输的过程中,将多跳传输与单跳传输相结合,从而实现了不兼容设备下的路由协议优化。实验结果表明,利用本文算法进行路由协议构建,能够降低网络的能量消耗和信息传输的延时率,提高了通信效率。 相似文献
3.
本文主要论述了IPV6协议相关知识,IPV4协议与IPV6协议的区别,近而论述了IPV4和IPV6转换地址技术,隧道技术,双堆栈功能。 相似文献
4.
IPV6协议是下一代互联网的核心,将取代现有的互联网协议IPV4。于是浅析了IPV6协议的推出的原因及其特点,简单说明了核心交换机IPV6应用的基本配置。 相似文献
5.
在使用无线网格网技术建设的网络中,其拓扑结构呈格栅状,通过路由协议快速形成超宽带网络,超宽带格栅状网络路由因为协议局限导致路由冲突,需要进行路由冲突在线重整,保证网络通信协议的安全稳定。传统的重整算法采用调制码元帧格式扫频方法实现路由信道均衡,优化任务调度,当网络信道的扩展损失呈突变衰减时,路由冲突重整效果不好。提出一种基于射线模型的超宽带栅状路由冲突重整算法,使用线性异域网络编码方式构建格栅状网络环式路由模型,采用射线模型构建邻居节点网络路由统计学模型,分析路由冲突信号的超宽带特征。计算超宽带格栅状路由协议的链路跨层信息,得到网络通信信道系统函数,根据多目标优化理论,把路由冲突协议叠加到射线模型的波动方程,实现基于射线模型的路由冲突优化重整。仿真实验结果表明,该算法能有效提高路由负载的均衡度,展示了算法优越的性能。 相似文献
6.
文章针对路由映射的策略应用,挖掘路由映射在路由重分配当中设置选择性匹配准则的作用。从IPv4动态路由协议开始进行案例分析,选取了常见的RIPng、IS-IS(for IPv6)等动态路由协议,进而研究了路由映射在IPv6基础上的路由重分配应用。 相似文献
7.
路由技术是无线传感器网络通信层的核心技术。从路由的角度来看,无线传感器网络有其自身的特点,使它既不同于传统网络,又不同于无线自组网ad-hoc网络。它的研究已经成为无线传感器网络研究中的热点。本文着重介绍了无线传感器网络路由协议的特点及其相关问题,对近年来针对于无线传感器网络提出的路由协议进行了研究,按其不同的实现方法给出了一种分类,并且重点分析了一种非常有效的可靠式路由协议:SPEED协议。 相似文献
8.
策力木格 《内蒙古科技与经济》2005,(9):135-136
多约束QoS路由是指寻找满足多个QoS约束条件的路由，被公认为是一个NP完全问题。现有很多启发式方法用来近似的解决该问题。本文简单介绍了如今常见的几种多约束QoS路由算法，并对其进行了简单分析。 相似文献
9.
对FallBack算法进行改进,先利用动态最短路径算法计算出最短路径,然后对路径进行QoS需求检查,最后进行调整,得到动态环境下具有多QoS保证的最优路径。该算法在一定程度上克服了路由信息不能得到及时更新所引起的问题,根据网络拓扑结构变化和流量的变化动态调整路由选择,从而更好地保证了服务质量。最后将此策略引入到OSPF路由协议中,提出一种综合性的路由更新机制,在尽可能最少的网络负载下满足QOS对链路状态信息的要求,从而在一定程度上扩展了OSPF路由协议的服务质量。 相似文献
10.
IPv6以其丰富的IP地址资源、安全性、网络管理、服务质量等方面的优势,必将成为替代IPV4的新一代网际协议。由于IPv6协议不能完全兼容IPv4协议,因此IPv4协议向IPv6协议过渡的过程,将利用现有IPv4互连网络资源,采取逐步过渡的方式进行,CNGI网络（即下一代互联网）作为采用IPV6协议的下一代互联网将在较长的一段时间内与目前的IPV4网络共存。 相似文献
11.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
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. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US 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 the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
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. 相似文献
13.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
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. 相似文献
14.
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. 相似文献
15.
A research 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 in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
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. 相似文献
16.
Puay Tang 《The Information Society》1998,14(1):19-31
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. 相似文献
17.
Milton Mueller 《The Information Society》2001,17(3):151-163
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. 相似文献
18.
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.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
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. 相似文献
19.
Active biological molecules 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 therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
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. 相似文献
20.
《中国科学院院刊(英文版)》2014,(3)
<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 相似文献