Abstract: A sensor network and method for task maintenance query using a query cache are provided. When a query generated by a user is transmitted through a relay node to a sensor node, the relay node can accurately transmit the query to a newly installed sensor node or a sensor node moving from another area to a specific area using a query cache. Thus, the reliability of the transmission of the query can be improved, and thus a task of the query can be maintained.

Abstract: A method of processing emergent data in a wireless sensor network is provided in which the latest information is collected from each sensor node and stored, newly-received sensing data are determined as emergent data if an error is over a certain value compared to the latest information from each node, and the emergent data are added with average data of neighbor nodes and transmitted to a sink node. Accordingly, whether neighbor sensor nodes are normal in a wireless sensor network can be determined and managed. An intermediate node can process emergent data generated from each sensor node and separate data by a sensor malfunction or urgent data so that a malfunction of each sensor node can be easily determined and reliability of sensing data of each sensor node can be improved.