Node-Replacement Policies to Maintain Threshold-Coverage in Wireless Sensor Networks - Sachin Parikh; Vinod Vokkarane; Liudong Xing; Dayalan Kasilingam (Proceedings of the 16th International Conference on Computer Communications and Networks, IEEE ICCCN 2007, Turtle Bay Resort, Honolulu, Hawaii, USA, August 13-16, 2007, 2007)