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1.
本文提出了一种新的P2P网络信任模型——层次化分布域信任模型HDRTM。该模型基于历史交互信息和信誉推荐,采用量化方法和合成规则方法得到的信任度对P2P网络中的节点信任进行评估,同时引入了惩罚调节因子、合成规则权重因子等加强了信任度的可靠性与真实性。对HDRTM的仿真证明能够有效抵制恶意节点,具有较好的安全性与信任性。 相似文献
2.
层次化分布域信任模型采用量化方法和合成规则方法得到的信任度对P2P网络中的节点信任进行评估,通过以往交互对该节点能力的认识不断加深和完善,从而形成对节点能否完成后续任务所做出的一种推断,然后利用这种推断来指导节点后续的行为,使得节点能够面临较小的风险而获得较好的服务。本文对层次化分布域信任模型系统的超级节点的形成过程、独立节点加入过程、节点离开过程三方面进行了详细阐述。 相似文献
3.
基于移动Ad Hoc网络的PKI/CA系统互操作模型 总被引：2，自引：1，他引：1
移动Ad Hoc网络(MANET)是由若干无线移动节点组成的不依赖于任何固定基础设施和集中式组织管理机构,而通过节点间的相互协作进行网络互联的一种多跳自组织临时性自治网络系统。在建立移动Ad Hoc网络多域全分布式PKI／CA系统过程中,在对国内外互操作技术及模型进行研究的基础上,提出了扩展推荐信任模型及相应的CA互操作结构模型,通过动态信任路径管理模式和认证机构信任列表实现CA间信任关系的管理和维护,提高了系统的安全性、可伸缩性和鲁棒性。 相似文献
4.
P2SP模式融合了服务器模式和P2P模式两者的技术优势,可以提供高效率、低成本的信息服务.本文分析了P2SP的结构,构建了基于多信任域的P2SP对等体认证模型.根据Dempster-Shafer证据理论定义了域间认证的置信区间,并建立了信任传递机制. 相似文献
5.
本文从基于P2P搜索的发展动机和原理入手,提出了一种层次化分布式哈希表系统——PDHS模型。该系统按物理网络的远近把节点划分为多个组,使得节点动态加入和退出的影响局限在单个组中,具有良好的稳定性和扩展性,部分查询的性能优越,适合在广域范围部署P2P应用。 相似文献
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7.
移动Ad Hoc网络（MANET）是一种不依赖于任何固定基础设施和集中式组织管理机构的具有全新概念的无线网络,通过无线链路实现移动节点间通信。然而Ad Hoc网络的固有特性使其面临严重的安全问题,针对这种网络环境,提出了建立安全系统所要遵循的基本要素,分析了国内外现有安全解决方案存在的问题。在对信任模型研究的基础上提出了基于局部分布式信任模型和扩展推荐信任模型的多域全分布式CA系统模型,能充分满足系统对容错性、安全性、可用性和可伸缩性的要求。 相似文献
8.
网格环境中的信任问题是当前网格研究的一个热点问题，根据网格的特点，提出了一个改进的以城为单位的分层信任模型，包括域间信任关系和域内信任关系，介绍了域间信任的计算模型，并对信任关系的度量、传递和合并过程进行了研究。 相似文献
9.
P2P网络的认证方法研究（英文） 总被引：1，自引：0，他引：1
P2P网络离散、动态和自治的特点使得传统的认证方法不能很好的解决其认证问题。本文采用证书和信任值相结合的方式，提出了一个新的认证协议APExSPKI用于解决P2P网络中节点之间的互认证问题。信任值绑定在证书中使得节点在身份认证的同时还可以进行授权和访问控制操作。 此外APExSPKI不需要可信服务器的参与，它允许网络中的任何节点参与到认证的过程中来，参与信任值投票并可充当代理节点来为其他节点颁发证书，这充分体现了节点对等、自治的特点。 相似文献
10.
对等计算环境(P2P)具有开放性以及对等节点的匿名性和自治的特点,由于缺乏对与之交互的节点的可信程度的知识,相互信任问题成为P2P进一步研究的一个重要方面.为了解决这一问题,提出一种在P2P环境下基于小世界特性的信任机制,通过彼此联系紧密的节点组成社区,反馈使社区内节点实时学习其所关心节点的信任情况.实验结果表明该机制的可行性和有效性,具有较好的信任收敛度和对恶意行为的防范效果.从而保证了P2P环境下请求节点获得服务的可靠性和安全性. 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.
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
16.
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
17.
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
18.
Leah A. Lievrouw 《The Information Society》1998,14(2):83-96
The main premise of this article is that in information societies generally, and in virtual social contexts particularly, a distinctive style of interaction to facilitate the communication of difference, heterotopic communication , has emerged. It rests on two cultural foundations: an ideological belief in the positive, socially integrating power of communication, and a prevailing ethic of instrumental rationality, subjective individualism, and strategically practiced self-interest. The former is demonstrated by the use of simulation and spectacle as sources of information; exhibitionism/voyeurism as a communicative style; and the awareness of surveillance. The latter is seen in the competitive use of knowledge as a commodity; a surface globalism masking deep parochialism; lateral as well as vertical information inequity; and the use of public versus private as strategies for engagement rather than as spaces. Those who engage in heterotopic communication resort to their 'own devices' both in the sense of personal agendas, strategies, interests, and interpretations, and in the form of the telecommunication tools that help realize them. These personal and technological devices allow individuals with the right educational and technical resources to avoid exposure to disagreement, difference, or other information that does not serve their direct purposes or reflect their particular views of the world; yet they also help convey the appearance of openness, availability, and cooperation. This style of interaction is used strategically in combination with information and communication technologies to gain social or economic advantages, but it may encourage social separatism and parochialism, inhibit the negotiation of disputes, and emphasize competing interests. 相似文献
19.
《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
20.
Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<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 相似文献