The Experts below are selected from a list of 93492 Experts worldwide ranked by ideXlab platform
Jamie Callan - One of the best experts on this subject based on the ideXlab platform.
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Full-text federated search of text-based digital libraries in Peer-to-Peer Networks
Information Retrieval, 2006Co-Authors: Jamie CallanAbstract:Peer-to-Peer (P2P) Networks integrate autonomous computing resources without requiring a central coordinating authority, which makes them a potentially robust and scalable model for providing federated search capability to large-scale Networks of text-based digital libraries. However, Peer-to-Peer Networks have so far provided very limited support for full-text federated search with relevance-based document ranking. This paper provides solutions to full-text federated search of text-based digital libraries in hierarchical Peer-to-Peer Networks. Existing approaches to full-text search are adapted and new methods are developed for the problems of resource representation, resource selection, and result merging according to the unique characteristics of hierarchical Peer-to-Peer Networks. Experimental results demonstrate that the proposed approaches offer a better combination of accuracy and efficiency than more common alternatives for federated search of text-based digital libraries in Peer-to-Peer Networks.
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user modeling for full text federated search in Peer to Peer Networks
International ACM SIGIR Conference on Research and Development in Information Retrieval, 2006Co-Authors: Jamie CallanAbstract:User modeling for information retrieval has mostly been studied to improve the effectiveness of information access in centralized repositories. In this paper we explore user modeling in the context of full-text federated search in Peer-to-Peer Networks. Our approach models a user's persistent, long-term interests based on past queries, and uses the model to improve search efficiency for future queries that represent interests similar to past queries. Our approach also enables queries representing a user's transient, ad-hoc interests to be automatically recognized so that search for these queries can rely on a relatively large search radius to avoid sacrificing effectiveness for efficiency. Experimental results demonstrate that our approach can significantly improve the efficiency of full-text federated search without degrading its accuracy. Furthermore, the proposed approach does not require a large amount of training data, and is robust to a range of parameter values.
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federated search of text based digital libraries in hierarchical Peer to Peer Networks
European Conference on Information Retrieval, 2005Co-Authors: Jamie CallanAbstract:Peer-to-Peer architectures are a potentially powerful model for developing large-scale Networks of text-based digital libraries, but Peer-to-Peer Networks have so far provided very limited support for text-based federated search of digital libraries using relevance-based ranking. This paper addresses the problems of resource representation, resource ranking and selection, and result merging for federated search of text-based digital libraries in hierarchical Peer-to-Peer Networks. Existing approaches to text-based federated search are adapted and new methods are developed for resource representation and resource selection according to the unique characteristics of hierarchical Peer-to-Peer Networks. Experimental results demonstrate that the proposed approaches offer a better combination of accuracy and efficiency than more common alternatives for federated search in Peer-to-Peer Networks.
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content based retrieval in hybrid Peer to Peer Networks
Conference on Information and Knowledge Management, 2003Co-Authors: Jie Lu, Jamie CallanAbstract:Hybrid Peer-to-Peer architectures use special nodes to provide directory services for regions of the network ("regional directory services"). Hybrid Peer-to-Peer architectures are a potentially powerful model for developing large-scale Networks of complex digital libraries, but Peer-to-Peer Networks have so far tended to use very simple methods of resource selection and document retrieval. In this paper, we study the application of content-based resource selection and document retrieval to hybrid Peer-to-Peer Networks. The directory nodes that provide regional directory services construct and use the content models of neighboring nodes to determine how to route query messages through the network. The leaf nodes that provide information use content-based retrieval to decide which documents to retrieve for queries. The experimental results demonstrate that using content-based retrieval in hybrid Peer-to-Peer Networks is both more accurate and more efficient for some digital library environments than more common alternatives such as Gnutella 0.6.
Julita Vassileva - One of the best experts on this subject based on the ideXlab platform.
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trust and reputation model in Peer to Peer Networks
International Conference on Peer-to-Peer Computing, 2003Co-Authors: Yao Wang, Julita VassilevaAbstract:It is important to enable Peers to represent and update their trust in other Peers in open Networks for sharing files, and especially services. We propose a Bayesian network-based trust model and a method for building reputation based on recommendations in Peer-to-Peer Networks. Since trust is multifaceted, Peers need to develop differentiated trust in different aspects of other Peers' capability. The Peer's needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer's capability or in multiple aspects. Bayesian Networks provide a flexible method to present differentiated trust and combine different aspects of trust. The evaluation of the model using a simulation shows that the system where Peers communicate their experiences (recommendations) outperforms the system where Peers do not share recommendations with each other and that a differentiated trust adds to the performance in terms of percentage of successful interactions.
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bayesian network trust model in Peer to Peer Networks
Lecture Notes in Computer Science, 2003Co-Authors: Yao Wang, Julita VassilevaAbstract:In this paper, we propose a Bayesian network-based trust model in Peer-to-Peer Networks. Since trust is multi-faceted, even in the same context, Peers still need to develop differentiated trust in different aspects of other Peers’ behaviors. The Peer’s needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer’s capability or in a combination of multiple aspects. Bayesian Networks provide a flexible method to represent differentiated trust and combine different aspects of trust.
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bayesian network based trust model in Peer to Peer Networks
2003Co-Authors: Yao Wang, Julita VassilevaAbstract:In this paper, we first review trust and reputation mechanisms from different perspectives. Then we propose a Bayesian network-based trust model and a method for building reputation based on recommendations in Peer-to-Peer Networks. Since trust is multi-faceted, Peers need to develop differentiated trust in different aspects of other Peers’ capability. The Peer’s needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer’s capability or in multiple aspects. Bayesian Networks provide a flexible method to present differentiated trust and combine different aspects of trust.
Yao Wang - One of the best experts on this subject based on the ideXlab platform.
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trust and reputation model in Peer to Peer Networks
International Conference on Peer-to-Peer Computing, 2003Co-Authors: Yao Wang, Julita VassilevaAbstract:It is important to enable Peers to represent and update their trust in other Peers in open Networks for sharing files, and especially services. We propose a Bayesian network-based trust model and a method for building reputation based on recommendations in Peer-to-Peer Networks. Since trust is multifaceted, Peers need to develop differentiated trust in different aspects of other Peers' capability. The Peer's needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer's capability or in multiple aspects. Bayesian Networks provide a flexible method to present differentiated trust and combine different aspects of trust. The evaluation of the model using a simulation shows that the system where Peers communicate their experiences (recommendations) outperforms the system where Peers do not share recommendations with each other and that a differentiated trust adds to the performance in terms of percentage of successful interactions.
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bayesian network trust model in Peer to Peer Networks
Lecture Notes in Computer Science, 2003Co-Authors: Yao Wang, Julita VassilevaAbstract:In this paper, we propose a Bayesian network-based trust model in Peer-to-Peer Networks. Since trust is multi-faceted, even in the same context, Peers still need to develop differentiated trust in different aspects of other Peers’ behaviors. The Peer’s needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer’s capability or in a combination of multiple aspects. Bayesian Networks provide a flexible method to represent differentiated trust and combine different aspects of trust.
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bayesian network based trust model in Peer to Peer Networks
2003Co-Authors: Yao Wang, Julita VassilevaAbstract:In this paper, we first review trust and reputation mechanisms from different perspectives. Then we propose a Bayesian network-based trust model and a method for building reputation based on recommendations in Peer-to-Peer Networks. Since trust is multi-faceted, Peers need to develop differentiated trust in different aspects of other Peers’ capability. The Peer’s needs are different in different situations. Depending on the situation, a Peer may need to consider its trust in a specific aspect of another Peer’s capability or in multiple aspects. Bayesian Networks provide a flexible method to present differentiated trust and combine different aspects of trust.
Liwei Yang - One of the best experts on this subject based on the ideXlab platform.
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on character based index schemes for complex wildcard search in Peer to Peer Networks
Information Sciences, 2014Co-Authors: Yuhjzer Joung, Liwei YangAbstract:We present a family of character-based index schemes for wildcard search in Peer-to-Peer Networks. The supported query format allows the two wildcard matching operators '?' and '*' to be used arbitrarily. To our knowledge, no distributed solution for this general form of wildcard search has been proposed thus far. Moreover, the schemes can achieve balanced loads, avoid hot-spots and single points of failure, reduce storage and maintenance costs, and offer ranking mechanisms for matching objects. The main focus is on a thorough comparative study on these index schemes from the following perspectives: query expressiveness, encoding effectiveness, load balance, and search performance.
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wildcard search in structured Peer to Peer Networks
IEEE Transactions on Knowledge and Data Engineering, 2007Co-Authors: Yuhjzer Joung, Liwei YangAbstract:We address wildcard search in structured Peer-to-Peer (P2P) Networks, which, to our knowledge, has not yet been explored in the literature. We begin by presenting an approach based on some well-known techniques in information retrieval (IR) and discuss why it is not appropriate in a distributed environment. We then present a simple and novel technique to index objects for wildcard search in a fully decentralized manner, along with some search strategies to retrieve objects. Our index scheme, as opposed to a traditional IR approach, can achieve quite balanced loads, avoid hop spots and single point of failure, reduce storage and maintenance costs, and offer some ranking mechanisms for matching objects. We use the compact disc (CD) records collected in FreeDB (http://freedb.org) as the experimental data set to evaluate our scheme. The results confirm that our index scheme is very effective in balancing the load. Moreover, search efficiency depends on the information given in a query: the more the information, the higher the performance.
Marta I Mulawa - One of the best experts on this subject based on the ideXlab platform.
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associations between Peer network gender norms and the perpetration of intimate partner violence among urban tanzanian men a multilevel analysis
Prevention Science, 2018Co-Authors: Marta I Mulawa, Lusajo Kajula, Luz Mcnaughton H Reyes, Vangie A Foshee, Carolyn Tucker Halpern, Sandra L Martin, Suzanne MamanAbstract:Male perpetration of intimate partner violence (IPV) against women in sub-Saharan Africa is widespread. Theory and empirical evidence suggest Peer Networks may play an important role in shaping IPV perpetration, though research on this topic in the region is limited. We assessed the degree to which Peer network gender norms are associated with Tanzanian men’s perpetration of IPV and examined whether the social cohesion of Peer Networks moderates this relationship. Using baseline data from sexually active men (n = 1103) nested within 59 Peer Networks enrolled in an on-going cluster-randomized HIV and IPV prevention trial, we fit multilevel logistic regression models to examine Peer network-level factors associated with past-year physical IPV perpetration. Peer network gender norms were significantly associated with men’s risk of perpetrating IPV, even after adjusting for their own attitudes toward gender roles (OR = 1.53 , p = . 04). Peer network social cohesion moderated this relationship (OR = 1.50 , p = . 04); the positive relationship between increasingly inequitable (i.e., traditional) Peer network gender norms and men’s risk of perpetrating IPV became stronger, as Peer network social cohesion increased. Characteristics of the Peer network context are associated with men’s IPV perpetration and should be targeted in future interventions. While many IPV prevention interventions focus on changing individual attitudes, our findings support a unique approach, focused on transforming the Peer context.
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Peer network influence on intimate partner violence perpetration among urban tanzanian men
Culture Health & Sexuality, 2018Co-Authors: Marta I Mulawa, Lusajo Kajula, Suzanne MamanAbstract:Male perpetration of intimate partner violence (IPV) against women in Tanzania is widespread. Theory and empirical evidence suggest Peer Networks may play an important role in shaping IPV perpetration, although research on this topic in sub-Saharan Africa is limited. Grounded in social learning theory, social influence theory, and the theory of gender and power, the purpose of this study was to examine whether and how Peer Networks influence men's perpetration of IPV in Dar es Salaam, Tanzania. We conducted in-depth interviews (n = 40) with a sub-sample of 20 men enrolled in the control condition of an ongoing cluster-randomised controlled trial. We purposively sampled participants who previously reported perpetrating physical IPV. To analyse the data, we generated narrative summaries and conducted thematic and interpretative coding. We saw no evidence that men self-selected into Peer Networks with certain values or behaviours. Rather, men described several mechanisms through which their Peers influenced the perpetration of IPV, including: (1) the internalisation of Peer network norms, (2) pressure to conform to Peer network norms and (3) the direct involvement of Peers in shaping couple power dynamics. Our findings suggest that Peer Networks influence men's perpetration of IPV and should be targeted in future programmes and interventions.
