| dc.description.abstract | Recently, scientific progress and hardware technology have made possible the development of wireless sensor nodes in small sizes with large memory capacity, low cost, and the multi-function, which allow a wide range of applications for wireless sensor network, such as in battlefield surveillance, calamity reporting, biomedicine, hazardous environment exploration, environmental monitoring, and position tracking. Since these applications must use sensor nodes to detect and track some specific events, the object detection and tracking protocol is a basic function for these applications. In this dissertation, our research focuses on detection and tracking of continuous objects in wireless sensor networks.
Most of the previous researches on object detection and tracking focus on individual objects, such as intruder, tank, vehicle, etc. The individual object can usually be detected by several neighboring sensor nodes, called event nodes. Therefore, the collaboration of event nodes and efficient transmission of object information to sink nodes are considered in designing individual object detection and tracking protocols. Compared with the individual object, the continuous object is usually larger in size and can diffuse, increase in size, or split into multiple continuous objects, such as forest fire, noxious gas, the social animal moving and the army advancing, which imply that there should be a lot more event nodes. Hence, the main challenge and goal for designing the continuous object detection and tracking protocol is to reduce the number of reporting information to the sink node for energy conservation in communication. Therefore, individual object detection and tracking protocols are unsuitable for continuous object detection and tracking.
In this dissertation, we propose two continuous object detection and tracking protocols: a scalable topology-control-based continuous object detection and tracking (STCB) protocol and a coverage-based continuous object detection and tracking (CBDT) protocol. In the STCB protocol, the event nodes close to the boundary of object will be selected as boundary nodes in a quick distribution manner. Moreover, the location of these selected boundary nodes can represent the location of all event nodes. Therefore, only boundary nodes report their location information to sink nodes; the sink nodes can estimate the location information of continuous objects. Two rules for reducing the boundary node, without spending extra communication cost, are also discussed in the STCB protocol.
The number of selected reporters in a continuous object is proportional to the length of object boundary no matter what size or how sharp the object is. In CBDT protocol, one or several core nodes will be determined from the boundary nodes for reporting continuous object information. The location of the core nodes and their determined hop count can represent all the locations of the event nodes. Therefore, only the core nodes report their information to the sink node; the communication cost in continuous object detection and tracking can be further reduced.
In wireless sensor network, each sensor node needs a unique node ID for communication. A sensor node with a unique node ID would be assumed in our object detection and tracking protocol. Therefore, we also proposed a new node ID assignment protocol for each sensor node that obtains a unique node ID quickly in the network initialization. Through the simulations, the proposed protocols are verified to be both efficient and cost-effective. | en_US |