A Two-phased Approach to Retrieving Learning Content in Peer-to-Peer Grids

P2P (peer-to-peer) teaching material sharing environments can avoid redundant efforts, and alleviate limitations resulting from centralized management and client-server modeling. However, the issues of availability and trustworthiness have to be considered in teaching material retrieval process, in order to improve the retrieval performance. Current peer-to-peer file sharing applications focus on exact matching and ignore the dynamic nature inherent in peer-to-peer networks, which might degrade the retrieval performance in terms of recall and response time. Our idea is to appropriately set the due time to improve response time of peer-to-peer teaching material retrieval without sacrificing much recall. The proposed approach consists of two phases: construction phase and sharing phase. In construction phase, peer information is acquired and managed in a decentralized manner. In sharing phase, the due time is interactively determined and the results are retrieved. A prototype system has been developed and experiments have been conducted to evaluate the performance of the approach. The experimental results show that the interactive algorithm performs well in peer-to-peer grids with low trust and availability.