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针对教学单位教育资源分布的特点,以带有主节点的P2P（P2P with Super-peer）网络为基本架构;以RDF／S为资源描述结构。构建了一个教育资源整合平台。解决了基于关系数据模式的虚拟RDF视图的构建;解决了SPARQL查询向SQL查询的转换,从而实现了异构教学资源之间的跨模式、跨语义的集成。为解决数据孤岛问题和进一步发布资源的链接数据作好准备,丰富了资源的价值。 相似文献
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用于改善web搜索的结构化数据抽取技术 总被引：1，自引：0，他引：1
为了提高web文本搜索质量,提出了基于语义结构化数据的查询扩展方法.通过分析属性的语义特征（文档频率特征和辨识能力特征）将属性分为概念属性、背景属性和无用属性3类,并且提出了衡量属性语义相关度的标准.设计了trie-bitmap和pair pointer table数据结构来实现发掘属性语义特征和检测属性语义相关度的有效算法.通过使用合适的属性和它们的语义关系,可以为查询关键字生成扩展词并将它们嵌入到具有插值参数的向量空间模型中.实验使用IMDB电影数据库和真实文本数据集来比较所提方法和原始向量空间模型的性能.实验结果证明所提出的查询扩展方法可以有效地提高文本搜索性能,同时属性语义特征和属性语义相关度都具有良好的分类能力. 相似文献
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根据无线传感网络能量受限的特点,提出一种低能耗路由算法SOC-IACO,算法由自组织聚类算法SOC和改进蚁群算法WAC组成.先通过SOC将节点分簇,选取簇头构造簇头数据链,再通过WAC构造簇内节点数据链.簇内数据沿节点数据链汇聚至簇头、簇头数据沿簇头数据链汇聚至总簇头,由总簇头发送数据至基站.实验表明,由于聚类过程中考虑了节点分布和簇负载均衡并采用双层链路由,SOC-IACO算法能大幅降低节点能耗提高网络寿命. 相似文献
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无线网络环境下,移动用户节点通过缓存技术降低数据访问的延迟,可以达到节省网络开销,提高服务质量的目的。设计一种基于兴趣-分簇的缓存放置策略,该策略对用户历史访问记录进行聚类分析进而提取关键词,使具有相似访问规律的节点聚合成逻辑网上的兴趣簇。针对MP2P网络的动态性等特征,节点之间的数据交换及共享在簇内进行,有效提高搜索匹配效率。 相似文献
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Deep web站点查询界面的潜在语义分析 总被引：1，自引：0，他引：1
为了进一步提高搜索引擎的效率,实现对deep web中所蕴含的大量有用信息的检索、索引和定位,引入潜在语义分析理论是一种简单而有效的方法.通过对作为deep web站点入口的查询界面里的表单属性进行潜在语义分析,从表单属性中挖掘出潜在语义结构,并实现一定程度上的降维.利用这种潜在语义结构,推断对应站点的数据内容并改善不同站点的相似度计算.实验结果显示,潜在语义分析修正和改善了deep web站点的表单属性的语义理解,弥补了单纯的关键字匹配带来的一些不足.该方法可以被用来实现为某一站点查找网络上相似度高的站点及通过键入表单属性给出拥有相似表单的站点列表. 相似文献
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采用一种神经网络算法——径向基函数来选择无线传感器网络的节点簇首,它具有并行处理能力、分布式存储以及快速学习等优点.通过分析得出与节点作为簇首相关的4个因素:节点的剩余能量,周围分布的节点的数目,中心度和距离基站的位置.把这4个因素作为神经网络的输入变量,输出变量就是该节点作为簇首的适应度值.根据网络规模的大小,基站选出一组作为簇首的节点,然后广播作为簇首的节点号的消息.如果一个节点被选为簇首,就向周围广播自己的身份并成立一个新簇,周围的非簇首节点要求加入该簇并成为它的成员.每簇中由簇首负责管理它的成员并执行数据融合等功能.实验结果表明,与其他算法相比,该算法能显著地延长传感器网络的生命. 相似文献
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杨亚华 《中小学图书情报世界》2008,(5):53-55
在P2P（peer to peer）网络上．创建一个分布式的信息检索环境．将P2P与Z39．50相互结合,实现分布式数字图书馆信息检索、交互等功能,满足信息用户的个性化需求。 相似文献
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杨丽玲 《Journal of Zhangzhou Technical Institute》2009,11(2):1-3
分类问题的覆盖算法为处理海量数据提供了一个十分有效的方法,已被广泛应用于文本分类问题中.主要通过覆盖算法、核覆盖算法和基于概率的覆盖算法等三种不同方法进行训练和学习,并根据给出的实验结果进行比较研究.实验结果表明了经优化后的概率模型在文本分类中提高了识别率和精确度. 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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ZUO Dong-hong DU Xu YANG Zong-kai 《浙江大学学报(A卷英文版)》2007,8(8):1191-1198
Media streaming delivery in wireless ad hoc networks is challenging due to the stringent resource restrictions,po-tential high loss rate and the decentralized architecture. To support long and high-quality streams,one viable approach is that a media stream is partitioned into segments,and then the segments are replicated in a network and served in a peer-to-peer(P2P) fashion. However,the searching strategy for segments is one key problem with the approach. This paper proposes a hybrid ants-like search algorithm(HASA) for P2P media streaming distribution in ad hoc networks. It takes the advantages of random walks and ants-like algorithms for searching in unstructured P2P networks,such as low transmitting latency,less jitter times,and low unnecessary traffic. We quantify the performance of our scheme in terms of response time,jitter times,and network messages for media streaming distribution. Simulation results showed that it can effectively improve the search efficiency for P2P media streaming distribution in ad hoc networks. 相似文献
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Allan Nicholas 《Pedagogies: An International Journal》2016,11(1):22-42
This study investigates the extent to which Japanese learners of English as a Foreign Language (EFL) are able to offer mediation to their peers while engaging in pair work, and whether that mediation is sensitive to the needs of their partner. Grounded in sociocultural theory, the study assesses the extent to which the study participants identify and respond to a partner’s developmental level, offering appropriate help. Further, evidence in the data of learner development is examined. Six first-year university learners of EFL participated in the study, and were placed in to three pairs. Each pair was given a set of pictures in random order, and was asked to construct a story from the pictures, first orally, then in writing, working together closely with their co-participant. The audio-recorded sessions were transcribed and analysed for instances of developmentally sensitive peer–peer assistance. Numerous examples were found throughout the data showing all study participants being capable and willing to offer such assistance to their peers. Further, evidence was found of the assistance leading to microgenetic development in task performance. 相似文献
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David Nicol Avril Thomson Caroline Breslin 《Assessment & Evaluation in Higher Education》2014,39(1):102-122
Peer review is a reciprocal process whereby students produce feedback reviews on the work of peers and receive feedback reviews from peers on their own work. Prior research has primarily examined the learning benefits that result from the receipt of feedback reviews, with few studies specifically exploring the merits of producing feedback reviews or the learning mechanisms that this activates. Using accounts of their experiences of peer review, this study illuminates students’ perceptions of the different learning benefits resulting from feedback receipt and feedback production, and, importantly, it provides insight into the cognitive processes that are activated when students construct feedback reviews. The findings show that producing feedback reviews engages students in multiple acts of evaluative judgement, both about the work of peers, and, through a reflective process, about their own work; that it involves them in both invoking and applying criteria to explain those judgements; and that it shifts control of feedback processes into students’ hands, a shift that can reduce their need for external feedback. The theoretical and practical implications of these findings are discussed. It is argued that the capacity to produce quality feedback is a fundamental graduate skill, and, as such, it should receive much greater attention in higher education curricula. 相似文献
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A study of the interrelationship between the behaviour and social status of a class of Year 2 pupils
MELANIE SLADE 《Support for Learning》2008,23(2):63-70
The influence of social status on child development has been the subject of research for several decades, with children who are not accepted by their peers being shown to be at risk of a range of difficulties both at the time and in later life. Strong links have also been established between behaviour and social status. A small‐scale action research project considered the social structure of a Year 2 class and used data gathered through sociometric interviews and observations to identify some factors which may have influenced the social status of individuals within that group. From this data, three children considered at risk of peer rejection or isolation were identified and an intervention programme was implemented. At the end of the year sociometric interviews and observations were repeated and it was found that one child's social behaviours and status among his peers had increased significantly over the course of the project. 相似文献
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TaChord:利用拓扑相关路由算法和超级节点的Chord系统 总被引：7，自引：0，他引：7
由于未考虑实际网络拓扑结构,当前结构化对等网络系统存在高延迟低效率的毛病. 本文提出一种与实际网络拓扑结构相关的路由方法,并开发出一种基于Chord的TaChord系统. 在仿真系统中, 用物理跳数、域间延迟和每个消息占用的带宽来衡量TaChord和其他系统的路由性能. 仿真结果表明,TaChord系统的路由性能有了极大的提高, 如平均物理跳数是Chord的一半,并且不同路由缓存管理策略对TaChord的路由性能能产生重要的影响. 相似文献
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结构化P2P网络研究 总被引：1，自引：0，他引：1
结构化P2P系统采用支持分布式哈希表（DHT）的路由算法，根据精确关键字进行对象的定位与发现。本文介绍了两种结构化P2P系统：CAN和Chord系统。重点分析了这两种结构化P2P系统的构建和路由算法以及对等节点加入和离开P2P系统的过程，并详细讨论了CAN和Chord的改进方案，最后指出了结构化P2P系统所面临的问题与不足。 相似文献
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In England teachers of secondary school mathematics and science are in short supply and it is important to understand how pre-service teachers develop and maintain networks of support during their training year and the impact these networks can have on their training outcomes. The purpose of this study is to examine how changes to the size and composition of these support networks during the training year are associated with programme outcomes. The paper draws on social network theory to examine the nature of the support networks that develop around each pre-service teacher, and examines how supportive ties were initiated, maintained, and broken over the course of the training year. A survey design was utilised to collect data at four time points across the 2014–2015 academic year from a total cohort of more than 75 pre-service teachers. At all four time points, participants were asked to nominate those peers and others to whom they had turned during the previous month for different aspects of support. Results showed that the size and composition of support networks changed over time with significant differences in the development of the networks between pre-service teachers on school-led and university-led programmes. 相似文献