Students’ educational use of Facebook groups

The aim of the article is to explore educational use of student-managed Facebook groups in upper secondary education (in Denmark). Much research on educational potentials of Facebook has studied groups managed by teachers. However, there is a lack of in-depth research on Facebook groups managed by students and without participation from teachers. As this study shows, students’ use of student-managed groups differs from their use of teacher-managed tools such as learning management systems (LMSs). The article presents an empirical study based partly on a content analysis of 3139 posts and 15,018 replies within five Facebook groups, and partly on a questionnaire answered by 1463 students and 148 teachers. The results of the study show that whereas LMSs were seen by students primarily as institutional systems of the teacher, Facebook groups have an educational potential to be used by students for peer-to-peer learning.     

Virtual and Dynamic Hierarchical Architecture:an overlay network topology for discovering grid services with high performance

INTRODUCTION Grid (Foster et al., 2001) technology is one ofthe most important ones to appear in recent years.The recent big progress is that scientists (Foster etal., 2002; Roure et al., 2001; Rana and Walker,2002) proposed service-oriented architectures suchas Open Grid Services Architecture (OGSA) (Fos-ter et al., 2002) that integrated the so-called com-putational/data Grid architecture (Foster et al.,2001) with Web services (Grid Web ServicesWorkshop, 2001). In the service-ori…     

SDQE: towards automatic semantic query optimization in P2P systems

Conventional information retrieval technology (i.e. VSM) faces many difficulties when being implemented in complex P2P systems for the lack of global statistic information (e.g. IDF) and central services. In this paper, we suggest a novel query optimization scheme (Semantic Dual Query Expansion, SDQE) that makes full use of the context information supplied by the local document collection. Latent Semantic Indexing (LSI) is used to explore the local context information. By comparing the different local context information hidden in different document collections, it is possible to solve the synonymy–polysemy problem in VSM. The experiments prove that our scheme is effective to improve the retrieval performance in P2P systems without knowing the global statistic information.     

Cluster-K: Network topology for searching replicated data in p2p systems

This paper proposes a new scheme for ensuring data consistency in unstructured p2p networks where peers can subscribe to multiple content types (identified by labels) and are rapidly informed of content updates. The idea is based on using a static tree structure, the Cluster-K⁺ tree, that maintains most of the structural information about peers and labels. A label denotes a set of replicated or co-related data in the network. The Cluster-K⁺ tree provides efficient retrieval, addition, deletion and consistent updates of labels. Our proposed structure guarantees a short response search time of O(H + K), where H denotes the height of the tree and K the degree of an internal tree node. We present theoretical analytic bounds for the worst-case performance. To verify the bounds, we also present experimental results obtained from a network simulation. The results demonstrate that the actual performance of our system is significantly better than the theoretical bounds.     

Digital copyright and the “new” controversy: Is the law moulding technology and innovation?

This exploratory article sets out to examine if and how the new digital copyright laws in the U.S. and Europe are affecting innovation on the Internet. It argues that these laws, in balance, at least to date, are having a positive effect on Internet innovation, despite the strident argument that these laws will inhibit innovation. The innovations the article discusses are peer-to-peer (P2P) file sharing technology and the new business models for music retailing that P2P has spawned. It concludes that digital copyright laws could create perverse incentives for innovation and wonders if legislators may not require a better understanding of the innovation process when crafting IP laws.     

Virtual and Dynamic Hierarchical Architecture: an overlay network topology for discovering grid services with high performance

This paper presents an overlay network topology called Virtual and Dynamic Hierarchical Architecture (VDHA) for discovering Grid services with high performance. Service discovery based on VDHA has scalable, autonomous, efficient, reliable and quick responsive. We propose two service discovery algorithms. Full Search Query and Discovery Protocol (FSQDP) discovers the nodes that match the request message from all N nodes, which has time complexity O(logN), space complexity O(nvg) (nvg being node numbers of each virtual group), and message-cost O(N), and Domain-Specific Query and Discovery Protocol (DSQDP) searches nodes in only specific domains with time complexity O(nvg), space complexity O(nvg), and message-cost O(nvg). In this paper, we also describe VDHA, its formal definition, and Grid Group Management Protocol.     

A “cluster” based search scheme in peer-to-peer network

This paper presents a “cluster” based search scheme in peer-to-peer network. The idea is based on the fact that data distribution in an information society has structured feature. We designed an algorithm to cluster peers that have similar interests. When receiving a query request, a peer will preferentially forward it to another peer which belongs to the same cluster and shares more similar interests. By this way search efficiency will be remarkably improved and at the same time good resilience against peer failure (the ability to withstand peer failure) is reserved.     

结构化的对等网络技术分析与研究

在目前流行的结构化的对等网络技术中,存在稳定性较差、路由延迟较长、吞吐率较低等不足。为提高网络的稳定性和减少路由延迟,文中针对网络结点的会话异构性、物理邻接性、访问局部性,提出了相应的设计方案。为提高网络的吞吐率,做好系统的拥塞控制,文中采用消息比特来注明网络的拥塞情况。     

Using bidirectional links to improve peer-to-peer lookup performance

INTRODUCTION Peer-to-peer computing has become a populardistributed computing paradigm. Efficient resourcelookup is essential for such systems. As we know, most of the deployed peer-to-peersystems are unstructured. Napster is based on a cen-tral directory and was in popular use during early daysSoon after, Gnutella and KaZaA were deployedwidely. However, all these popular unstructuredpeer-to-peer systems suffer from unscalability. Fortunately, there are new kinds of peer-to-peernetwor…     

P2P searching trends: 2002–2004

This paper presents the trends of searching queries by users from peer-to-peer (P2P) networks over an 18-month period from July 2002 to January 2004. Four data sets of search queries collected from Gnutella were studied to describe the searching trends. Major findings include (1) the percentage of duplicate queries ranging from 34% to 68% of total queries; (2) an increase in non-English queries; (3) an approximately half of searching queries specified for video or audio file types; (4) the stop word “the” accounting for one-third of total stop words; (5) the shift of queries from audio to video; and (6) P2P users demanding for timely entertainment and porn materials. Based on the findings, it is worthwhile for P2P developers to consider (1) system design that allows effective searching using multiple languages; and (2) techniques that eliminate stop words for faster searching.