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Sang-Wan KIM Yongbin YIM Hosung PARK Ki-Dong NAM Sang-Ha KIM
Energy-efficient tracking of continuous objects such as fluids, gases, and wild fires is one of the important challenging issues in wireless sensor networks. Many studies have focused on electing fewer nodes to report the boundary information of continuous objects for energy saving. However, this approach of using few reporting packets is very sensitive to packet loss. Many applications based on continuous objects tracking require timely and precise boundary information due to the danger posed by the objects. When transmission of reporting packets fails, applications are unable to track the boundary reliably and a delay is imposed to recover. The transmission failure can fatally degrade application performance. Thus, it is necessary to consider just-in-time recovery for reliable continuous object tracking. Nevertheless, most schemes did not consider the reliable tracking to handle the situation that packet loss happen. Recently, a scheme called I-COD with retransmission was proposed to recover lost packets but it leads to increasing both the energy consumption and the tracking latency owing to the retransmission. Thus, we propose a reliable tracking scheme that uses fast recovery with the redundant boundary information to track continuous objects in real-time and energy-efficiently. In the proposed scheme, neighbor nodes of boundary nodes gather the boundary information in duplicate and report the redundant boundary information. Then the sink node can recover the lost packets fast by using the redundant boundary information. The proposed scheme provides the reliable tracking with low latency and no retransmissions. In addition, the proposed scheme saves the energy by electing fewer nodes to report the boundary information and performing the recovery without retransmissions. Our simulation results show that the proposed scheme provides the energy-efficient and reliable tracking in real-time for the continuous objects.
Seung-Woo HONG Euisin LEE Ho-Yong RYU Sang-Ha KIM
For monitoring of a large-scale continuous object, a large number of sensor nodes might be participated with object detection and tracking. In order to reduce huge quantities of data from the sensor nodes, previous studies focus on representative selection for data reporting to a sink. However, they simply choose representatives among a large number of candidates without consideration of node deployment environments and detection accuracy. Hence, this letter proposes a novel object tracking scheme that first makes a small set of candidates and then chooses a small number of representatives in the set. Also, since the scheme also considers object alteration for representative selection, it can provide high energy-efficiency despite reducing data reporting.
Jung-Hwan KIM Kee-Bum KIM Sajjad Hussain CHAUHDARY Wencheng YANG Myong-Soon PARK
The proliferation of research on target detection and tracking in wireless sensor networks has kindled development of monitoring continuous objects such as fires and hazardous bio-chemical material diffusion. In this paper, we propose an energy-efficient algorithm that monitors a moving event region by selecting only a subset of nodes near object boundaries. The paper also shows that we can effectively reduce report message size. It is verified with performance analysis and simulation results that total average report message size as well as the number of nodes which transmit the report messages to the sink can be greatly reduced, especially when the density of nodes over the network field is high.