Wireless sensor and actor networks(WSANs) refer to a group of sensors and actors linked by wireless medium, and a three-level framework composed of wireless sensor nodes, actors, and base stations ex-isted in WSANs. In this paper, an event-driven double-ring clustering algorithm for wireless sensor and actor networks(EDRCA) is presented, taking into account of the advantages of actors in aspects of power, computing ability and perception. The EDRCA links the actors in the shape of double-ring. This shape im...