+
+
+% use section* for acknowledgement
+\section*{Acknowledgment}
+
+
+
+
+\begin{thebibliography}{1}
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+
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+ M.~ Cardei ,~D.~ MacCallum ,~M.~ X.~ Cheng ,~M.~ Min ,~X.~ Jia ,~D.~ Li and
+ D.~ Du,~emph {Wireless Sensor Networks with Energy Efficient Organization},~Journal of Interconnection Networks,~ vol.~3,~ no.~3-4,pp.~213-229,~2002.
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+ M.~ Cardei ,~ J.~ Wu, N.~ Lu and M.~O.~ Pervaiz,~emph{Maximum Network Lifetime with Adjustable Range},~WiMob,~2005.
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+ M.~ Cardei ,~ M.~ T.~ Thai ,~Y.~ Li and W.~ Wu,~emph {Energy-efficient target coverage in wireless sensor networks},~INFOCOM,~pp.~1976-1984,~2005.
+
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+ P.~ Berman and G.~ Calinescu,~emph {Power Efficient Monitoring Management in Sensor Networks},~Proceedings of IEEE Wireless Communication and Networking Conference (WCNC'04),~pp.~2329--2334,~2004.
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+ A.~ Gallais,~ J.~ Carle ,~D. ~ Simplot-Ryl and I.~ Stojmenovic,~emph {Localized Sensor Area Coverage with Low Communication Overhead},~Proceedings of the Fourth Annual IEEE International Conference on Pervasive Computing and Communications,pp.~328--337,~2006.
+
+\bibitem{Tian02}
+ D. ~ Tian and N.~ D.~ Georganas, ~emph {A coverage-preserving node scheduling scheme for large wireless sensor networks},~Proceedings of the 1st ACM international workshop on Wireless sensor networks and applications,~pp.~ 32--41,~2002.
+
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+\bibitem{Ye03}
+F. ~Ye,G.~ Zhong,~J.~ Cheng,~S.~ Lu and L. ~ Zhang,~emph {PEAS: A Robust Energy Conserving Protocol for Long-lived Sensor Networks},~ Proceedings of the 23rd International Conference on Distributed Computing Systems ICDCS'03,~pp.~ 28--37,~2003.
+
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+\bibitem{Huang:2003:CPW:941350.941367}
+ C. ~ Huang and Y. ~ Tseng,~emph {The coverage problem in a wireless sensor network},~Proceedings of the 2nd ACM international conference on Wireless sensor networks and applications WSNA '03,~San Diego, CA, USA,~pp.~115-121,~ 2003.
+
+
+
+
+\bibitem{Zhang05}
+ H.~ Zhang and J.~ C.~ Hou,~emph {Maintaining Sensing Coverage and Connectivity in Large Sensor
+ Networks},~Ad Hoc {\&} Sensor Wireless Networks,~ vol.~1,no.~ 1-2,~2005.
+
+
+\bibitem{HeinzelmanCB02}
+ W.~ B.~ Heinzelman ,~ A.~ P.~ Chandrakasan and H.~ Balakrishnan,~emph {An application-specific protocol architecture for wireless microsensor networks},~IEEE Transactions on Wireless Communications,~ vol. ~1,~no. ~4,pp.~ 660-670,~2002.
+
+
+
+\bibitem{pedraza2006}
+ F. ~Pedraza,~A.~ L.~ Medaglia and A. ~ Garcia,~emph {Efficient coverage algorithms for wireless sensor networks},~Systems and Information Engineering Design Symposium,~ pp.~ 78 --83,~2006.
+
+
+\bibitem{chin2007}
+C.~ T. ~ Vu, ~ emph {An Energy-Efficient Distributed Algorithm for k-Coverage Problem in Wireless Sensor Networks},~GeorgiaState University,~2007.
+
+
+
+
+
+
+
+
+
+\end{thebibliography}
+
+
+
+
+
+
+% that's all folks
