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垃圾邮件已成为当今邮件系统的主要问题,垃圾邮件发送者通过伪装邮件来逃避反垃圾邮件系统的检测.针对目前的垃圾邮件过滤器大多数单机运行,所能获得的数据和信息较少,效率较低的问题,本文提出了一个点对点(P2P)的无服务器的E-mail系统的体系结构,系统测试结果表明,该系统结构有效地实现了相似邮件的聚集,从而达到了过滤垃圾邮件的目的. 相似文献
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目前,有很多的计算机支持的协同教学系统已经开发应用,但是这些系统都是使用客户端/服务器（C/S或B/S）计算模式来构建的。这种计算模式由于受单一服务器的计算能力及资源的限制,可扩展性较差;同时,系统可用性受服务器单点故障的影响,也很容易受到拒绝服务的攻击。本文提出了一种基于P2P计算模式的协同教学系统设计方案,以JXTAP2P网络平台为基础,对其协同工作中的几个关键问题进行研究分析,给出了系统框架的总体结构设计。文中提出的初步实例设计实现了一个典型的协同教学系统——虚拟教室,并对其性能进行了讨论分析。 相似文献
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A P2P streaming service architecture with distributed caching 总被引：3，自引：1，他引：3
GUO Pan-hong YANG Yang LI Xin-you 《浙江大学学报(A卷英文版)》2007,8(4):605-614
Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies. 相似文献
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分析了传统的单点登录存在的单点失效的缺陷,综合信任度和P2P技术提出了一种新的单点登录模型。一旦单点登录跨越了企业边界,则适合采用基于信任度的对等单点登录。在实际应用中,宜采用两者的混合体。 相似文献
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INTRODUCTION With the widespread deployment of broadband access, Video-on-Demand (VoD) streaming on the Internet has received increasing attention recently. In VoD service, video streams are delivered to asyn- chronous users with low delay and VCR-like opera- tion support (e.g., pause, fast-forward, and rewind). However, streaming to a large population of clients is very challenging due to the limited server capacity and little deployment of IP multicast in today’s Internet (Quinn a… 相似文献
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Antonio Calvani Antonio Fini Marcello Molino Maria Ranieri 《British journal of educational technology : journal of the Council for Educational Technology》2010,41(2):213-226
Online education based on small self‐managing groups, with slight supervision by a professional tutor, is a strategically interesting methodology for lifelong learning. This solution may combine aspects of cost‐effectiveness (reducing tutors' work) with the demands for active and engaging learning methods based on the exchange and sharing of experiences. In such a context, how can information on collaborative attitudes and behaviour be gathered? A typical tool for online learning activities is the threaded web forum. This study proposes a methodology for assessing effective collaborative interactions within the add‐on module, Forum Plus, for the Moodle learning management system (LMS). The methodology here presented is able to supply an early overview of the level of effectiveness of the collaborative group and therefore it may provide a useful instrument to guide further qualitative observations conducted directly in the web forum. 相似文献
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2016年底全国高校思想政治工作会议上,习近平总书记提出了各类课程与思想政治理论课同向同行,形成协同效应的新思路。当前,国内学者已对"课程思政"的必要性和重要性达成了共识,对影响"课程思政"实施的关键因素进行了分析,开始尝试构建"同向同行、协同育人"的新机制,并对"课程思政"的具体方法进行了理论探索与尝试性实践。为进一步推动"课程思政"改革,高校需以"思路攻坚"统一认识,以"师资攻坚"壮大力量,以"教材攻坚"丰富供给,以"教法攻坚"改善课堂,以"机制攻坚"明确方向。并在此原则下构建"课程思政"协同育人的体系,以道术合一推进理论课程协同育人,立德笃行推进实践课程协同育人,线上线下推进网络课程协同育人,善思善用推进项目课程协同创新,内外兼修推进补充课程协同育人,显隐相融推进专业课程协同育人。 相似文献
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ZHANG Ying YANG Yu XIE Qiu YUAN Qianbin LIU Fei 《重庆大学学报(英文版)》2006,5(4):200-204
1 Introduction ? With the advance in technology, accurate electromechanical instrument has been a critical tool to many breakthroughs in scientific and technological research. The collaboration and sharing of electromechanical instrument resources through… 相似文献
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为了更好地适应对Intemet中迅速发展的新形态P2P网络应用进行建模的需求,深入研究了适于描述多方并发网络交互的形式化建模方法.首先,对P2P网络系统模型的各项特征及其分类进行了探讨.然后,参照构件化建模的研究思路,基于对P2P应用建模需求的分析,提出了一种运用通信顺序进程(CSP)进行描述的P2P网络应用的形式化描述方法.借助CSP进程组表示,该方法能够更为方便精确地描述P2P系统中以多方交互为主的动态交互关系,探讨了CSP非确定性语义在P2P交互建模中的应用.最后通过一个新型P2P媒体点播系统的实例展示了以上描述方法的应用,验证了该方法在描述并行交互关系等方面的能力. 相似文献
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蒋雪玲 《宁波职业技术学院学报》2006,10(5):78-82
传统流媒体系统,受带宽和服务器限制,难以支持大规模并发客户。针对该问题,介绍了当前用P2P技术实现流媒体系统的现状,探讨了P2P的流媒体系统的系统结构及关键技术,分析了存在的问题,最后指出了P2P流媒体系统发展的研究方向。 相似文献
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This article proposes 7 core affordances of technology for collaborative learning based on theories of collaborative learning and CSCL (Computer-Supported Collaborative Learning) practices. Technology affords learner opportunities to (1) engage in a joint task, (2) communicate, (3) share resources, (4) engage in productive collaborative learning processes, (5) engage in co-construction, (6) monitor and regulate collaborative learning, and (7) find and build groups and communities. We elaborate our framework using in-depth explorations of how technologies are actually used to support collaborative learning in CSCL research and identify representative design strategies and technology examples. While technology can play an important role in addressing the demands of collaborative learning, it needs to be considered in conjunction with pedagogical strategies and other social and cultural supports for collaborative learning. The supports also need to remain at an appropriate level so as not to interfere with long-term learning goals. 相似文献
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Iftikhar Ahmed Muhammad Jafar Sadeq 《British journal of educational technology : journal of the Council for Educational Technology》2006,37(4):605-616
Current distance learning systems are increasingly packing highly data‐intensive contents on servers, resulting in the congestion of network and server resources at peak service times. A distributed learning system based on faded information field (FIF) architecture that employs mobile agents (MAs) has been proposed and simulated in this work. The learning contents are decentralised in the proposed system, and these are dynamically distributed around the main education site server on different nodes in response to network congestion and server overload. The system simulation results have been presented and analysed. The proposed system holds the potential to address the network congestion and server‐overload problems in distance learning systems. 相似文献
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基于语义叠加网的对等网搜索机制 总被引：1，自引：0，他引：1
针对目前超结点叠加网络研究中的不足,将语义信息引入到超节点的组织过程中,提出了一种新的对等网搜索模型———SSP2P.模型中结点依据小世界理论在物理上形成自然的区域自治系统(AAS),各AAS依据幂规律选取各域内的超结点,超结点再根据语义关系形成多个超结点语义网(SSN),从而形成一个层次化的超结点叠加网络模型.实验结果表明:该模型在保证系统扩展性的基础上有效地提高了搜索效率,减少了通信开销.证明在超节点叠加网络的构建过程中语义信息的引入有利于对等网搜索性能的提高. 相似文献
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邱碧珍 《福建工程学院学报》2016,(3):289-294
在分析技术接受模型（technology acceptance model,TAM）和任务技术匹配（task technology fit,TTF）整合的必要性的基础上,运用基于TAM和TTF整合的信息技术接受模型,采取二手资料和开放式问卷调查获取影响因素,构建出P2P网络借贷投资者接受模型。模型研究表明:感知风险是阻碍投资者使用P2P平台进行投资的最重要的影响因素。感知有用、感知收益和感知信任从一定程度上能促进投资者使用P2P平台进行投资。政策法规、P2P平台的质量、主观规范、感知行为控制对P2P平台投资也会产生一定的影响。同时,结合本研究模型提出了针对P2P平台应用和推广的建议。 相似文献
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栾丽琴 《泰州职业技术学院学报》2012,12(4):52-54
信息时代对现代图书馆的服务提出了新的要求。图书馆流通部门是图书馆对外服务的重要窗口,它处于图书馆工作的第一线。如何解决现有流通中存在的问题和矛盾,如何对流通服务方式和内容进行改进、创新,使流通服务工作更好地满足读者的需要,这是一个值得深思的问题。 相似文献
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INTRODUCTION Computer Supported Collaborative Work(CSCW) refers to technologies that use computertechnologies, multimedia technologies and networkcommunication technologies to support geogra-phically distributed users to collaborate with designtasks under shared environments. It is argued thatthe product development period may be shortenedgreatly when users independently and collabora-tively join in the designing, planning and assemblyprocess with the same product under a distributedenv… 相似文献
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This paper presents a novel Web Service based distributed collaborative CAD system employing feature as its collaborative design element and uses XML to define feature operations and communication protocol between the server and the client. To reduce network load and increase response ability of the system, the feature information is updated incrementally on the client. The system supports collaborative designing on heterogeneous platforms. Its framework and communication protocols are analyzed in detail. The experimental results from the developed prototype system showed that it can effectively support collaborative design under the distributed environment. 相似文献
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基于P2P技术的对等网络关键技术研究与分析 总被引：1，自引：0，他引：1
郭玉堂 《安徽教育学院学报》2005,23(6):43-46
介绍了基于P2P技术的对等网络的基本特征、关键技术及对等网络的分类,详细分析了对等网关键技术对网络的可靠性、可扩展性、适应性及完整性等性能的影响,最后展望了对等网络未来的发展方向. 相似文献