Efficient framework for processing top-k queries with replication in mobile ad hoc networks

This article addresses the top-k query processing problem on mobile ad hoc networks (MANETs). Top-k query processing is common to retrieve only highly important data items. However, methods for top-k query processing are not enough efficient and accurate in MANET environments. For improving the efficiency and accuracy, replication is a promising technique that each node in MANETs replicates data items retained by other nodes into its storage. Therefore, we fully combine the top-k query processing with data replication. We propose a framework that efficiently processes top-k queries based on a new replication strategy. We develop new replication strategy FReT (topology-Free Replication for Top-k query). FReT determines near-optimal allocations of replicas. It advantages efficient top-k query processing from limited search area without maintenance costs even if mobile nodes move. Our top-k query processing methods retrieve the exact answer with small overhead and delay by gradually increasing the search area based on FReT. We demonstrate, through extensive experiments, that FReT and query processing methods function well in terms of small delay and overhead without sacrificing exactness of the query result.