HONG KONG BAPTIST UNIVERSITY
FACULTY OF SCIENCE
Department of Computer Science Seminar
Maximizing Lifetime of Sensor-Target Surveillance in Sensor Wireless Networks
Dr. Hai Liu
Department of Computer Science
Hong Kong Baptist University
Date: November 24, 2008 (Monday)
Time: 3:30 - 4:30 pm
Venue: RRS905, Sir Run Run Shaw Building, Ho Sin Hang Campus
A wireless sensor network consists of many low-cost and low-powered sensor nodes that collaborate with each other to gather, process, and communicate information using wireless communications. A typical application of wireless sensor networks is to use sensors to monitor/watch targets in a sensing field. In a sensor-target surveillance network, sensors are placed to watch targets, collect information and then forward the data to the base station (BS) which is normally far away from the sensing field. These tiny sensor nodes are powered by batteries and have stringent power budget. We study the maximal lifetime scheduling problem in sensor-target surveillance networks. Given a set of sensors and targets in an Euclidean plane, the sensors are used to watch the targets and each target should be watched by at least one sensor at any time. The problem is to schedule sensors to watch targets and forward the sensed data to the BS, such that the lifetime of the surveillance network is maximized, where the lifetime is the duration that all targets are watched and all active sensors are connected to the BS. We propose an optimal solution to find the target-watching schedule for sensors that achieves the maximal lifetime. Our solution consists of three steps: 1) computing the maximal lifetime of the surveillance network and a workload matrix by using the linear programming technique; 2) decomposing the workload matrix into a sequence of schedule matrices by using the perfect matching technique; 3) determining the sensor surveillance trees based on the above obtained schedule matrices, which specify the active sensors and the routes to pass sensed data to the BS. The proposed optimal solution is illustrated by a numeric example and experiments.
Hai Liu joined the Dept of Computer Science at Hong Kong Baptist University as an Assistant Professor in 2008. He was a postdoctoral fellow with the School of information Technology and Engineering at University of Ottawa from 2007 to 2008. Hai Liu received Ph.D. in computer science from City University of Hong Kong in 2006. He received B.Sc. and M.Sc. in applied mathematics from South China University of Technology in 1999 and 2002, respectively. His research interests include wireless networking, mobile computing, and algorithm design and analysis. He has published over 30 research papers in international conferences, journals and books, including INFOCOM, IEEE/ACM Transactions on Networking, IEEE Transactions on Parallel and Distributed Systems, IEEE Transactions on Mobile Computing and Computer Networks. He served in TPC for various international conferences. He is a member of IEEE.
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Department of Computer Science, Hong Kong Baptist University