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báo cáo hóa học:" Research Article Perimeter Coverage Scheduling in Wireless Sensor Networks Using Sensors with a Single Continuous Cover Range"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Research Article Perimeter Coverage Scheduling in Wireless Sensor Networks Using Sensors with a Single Continuous Cover Range | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 926075 17 pages doi 10.1155 2010 926075 Research Article Perimeter Coverage Scheduling in Wireless Sensor Networks Using Sensors with a Single Continuous Cover Range Ka-Shun Hung and King-Shan Lui Department of Electrical and Electronics Engineering The University of Hong Kong Pokfulam Road Hong Kong Correspondence should be addressed to Ka-Shun Hung kshung@eee.hku.hk Received 21 September 2009 Revised 27 January 2010 Accepted 24 February 2010 Academic Editor Yu Wang Copyright 2010 K.-S. Hung and K.-S. Lui. This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. In target monitoring problem it is generally assumed that the whole target object can be monitored by a single sensor if the target falls within its sensing range. Unfortunately this assumption becomes invalid when the target object is very large that a sensor can only monitor part of it. In this paper we study the perimeter coverage problem where the perimeter of a big object needs to be monitored but each sensor can only cover a single continuous portion of the perimeter. We describe how to schedule the sensors so as to maximize the network lifetime in this problem. We formally prove that the perimeter coverage scheduling problem is NP-hard in general. However polynomial time solution exists in some special cases. We further identify the sufficient conditions for a scheduling algorithm to be a 2-approximation solution to the general problem and propose a simple distributed 2-approximation solution with a small message overhead. 1. Introduction Wireless sensor networks have caught lots of attention in recent years. One of the major problems is the coverage problem. Traditionally coverage problems concern whether a certain target area or a .