A Proposal of New Join Operators for Sensor Network Databases

Most sensor networks currently used to gather sensing data from a broad environment in which it is very difficult to deploy the existing networks (e.g., internet). Recently, researches on relational database approaches to sensor networks are being tried. There occur, however, some problems in applying directly the traditional relational database concepts into a sensor network. One reason is because the join operator only allows to perform operations on tuples which has exactly same join attribute values. For instance, let us assume a sensor network that two different classes of nodes are randomly scattered in the same area. We cannot get join results to know the relationship between two different classes of sensing values because there might be no nodes at a exactly same location. For a solution about the above described problem we propose in this paper new join operators. These new join operators can provide more effective data management and standard interfaces to application programs in sensor networks.