Data Replication for Top-k Query Processing in Mobile Wireless Sensor Networks

In mobile wireless sensor networks (MWSNs), since sensor nodes are highly resource constrained, it is effective to retrieve sensor observations using a top-k query, in which the observations are ordered by the value (or score) of a particular type of sensor, and the query-issuing node acquires sensor observations with the $k$ highest scores. In our previous work, we proposed a message processing method for a top-k query in mobile ad hoc networks (MANETs) for reducing traffic and keeping the accuracy of the query result. This method basically works well, however, it cannot avoid the deterioration of the accuracy when network partitioning occurs. In this paper, we assume MWSNs and propose data replication methods for keeping high accuracy of the query result even at the point of network partitioning. The proposed methods replicate sensor observations with high scores when each node sends and relays sensor observations to the query-issuing node.