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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 ε-Net Approach to Sensor k-Coverage Giordano Fusco and Himanshu Gupta | Hindawi Publishing Corporation EURASIP Journal on Wireless Communications and Networking Volume 2010 Article ID 192752 12 pages doi 10.1155 2010 192752 Research Article f-Net Approach to Sensor k-Coverage Giordano Fusco and Himanshu Gupta Computer Science Department Stony Brook University Stony Brook NY 11790 USA Correspondence should be addressed to Giordano Fusco fusco@cs.sunysb.edu Received 31 August 2009 Accepted 10 September 2009 Academic Editor Benyuan Liu Copyright 2010 G. Fusco and H. Gupta. 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. Wireless sensors rely on battery power and in many applications it is difficult or prohibitive to replace them. Hence in order to prolongate the system s lifetime some sensors can be kept inactive while others perform all the tasks. In this paper we study the k-coverage problem of activating the minimum number of sensors to ensure that every point in the area is covered by at least k sensors. This ensures higher fault tolerance robustness and improves many operations among which position detection and intrusion detection. The k-coverage problem is trivially NP-complete and hence we can only provide approximation algorithms. In this paper we present an algorithm based on an extension of the classical e-net technique. This method gives an O logM -approximation where M is the number of sensors in an optimal solution. We do not make any particular assumption on the shape of the areas covered by each sensor besides that they must be closed connected and without holes. 1. Introduction Coverage problems have been extensively studied in the context of sensor networks see e.g. 1-4 . The objective of sensor coverage problems is to minimize the number of active sensors to conserve energy usage while ensuring that the required region is sufficiently monitored by the active .
