ited number of storages,and we leverage the characteristics for sensor networks,"in CIKM,2006. of large scale sensor network to sufficiently reduce the com- [16 B.Sheng,Q.Li,and W.Mao.,"Optimize storage puting complexity of our optimization methodologies.Simu- placement in sensor networks,"IEEE Transactions on lation results confirm the performance of our methodologies Mobile Computing,vol.9,no.10,pp.1437-1450,2010 for storage placement over large scale sensor networks [17 B.Sheng,Q.Li,and W.Mao,"An approximation algorithm for data storage placement in sensor ACKNOWLEDGEMENT networks,"in WASA,2007. This work is partially supported by the National Natural Science Foundation of China under Grant No.61100196. 61073028.61021062:the National Basic Research Program of China (973)under Grant No.2009CB320705:the JiangSu Natural Science Foundation under Grant No.BK2011559. 10.REFERENCES 1 Y.Yao and J.Gehrke,"Query processing in sensor networks,"in CIDR,2003. [2]S.Madden,M.J.Franklin,J.M.Hellerstein,and W.Hong,"Tag:A tiny aggregation service for ad-hoc sensor networks."in Proceedings of OSDI.2002. [3]S.Scott,R.Sylvia,K.Brad,G.Ramesh,and E.Deborah,"Data-centric storage in sensornets." ACM SIGCOMM Computer Communication Review. vol.33.no.1,pp.137-142,2003. 4 S.Kapadia and B.Krishnamachari,"Comparative analysis of push-pull query strategies for wireless sensor networks,"in DCOSS,2006. 5 B.Sheng,Q.Li,and W.Mao,"Data storage placement in sensor networks,"in MobiHoc,2006 [6]R.Sylvia,K.Brad,S.Scott,E.Deborah,G.Ramesh, Y.Li,and Y.Fang,"Data-centric storage in sensornets with ght,a geographic hash table,"Mobile Net-works and Applications,vol.8,no.4,pp.427-442,2003. [7]G.Deepak,E.Deborah,and H.John,"Dimensions: Why do we need a new data handling architecture for sensor networks,"ACM SIGCOMM Computer Communication Review,vol.33,no.1,pp.143-148, 2003. (8]X.Li,Y.J.Kim,R.Govindan,and W.Hong, "Multi-dimensional range queries in sensor networks," in Sensys,2003. 9 R.Sarkar,X.J.Zhu,and J.Gao,"Double rulings for information brokerage in sensor networks,"in MOBICOM.2006. 10 X.Liu,Q.Huang,and Y.Zhang,"Combs, needles,haystacks:balancing push and pull for discovery in large-scale sensor networks,"in Sensys, 2004. [11]Q.Fang,J.Gao,and L.J.Guibas,"Landmark-based information storage and retrieval in sensor networks," in INFOCOM.2006. [12]N.Trigoni,Y.Yao,A.Demers,J.Gehrke,and R.Rajaraman."Hybrid push-pull query processing for sensor networks,"GI Jahrestagung,no.2,pp.370-374 13 J.Ahn and B.Krishnamachari,"Fundamental scaling laws for energy-efficient storage and querying in wireless sensor networks,"in MobiHoc,2006. 14 W.Zhang,G.Cao,and T.F.LaPorta,"Data dissemination with ring-based index for wireless sensor networks,"in ICNP,2003. [15]M.Aly,K.Pruhs,and P.K.Chrysanthis,"Kddcs:a load-balanced in-network data-centric storage schemeited number of storages, and we leverage the characteristics of large scale sensor network to sufficiently reduce the com￾puting complexity of our optimization methodologies. Simu￾lation results confirm the performance of our methodologies for storage placement over large scale sensor networks. 9. ACKNOWLEDGEMENT This work is partially supported by the National Natural Science Foundation of China under Grant No. 61100196, 61073028, 61021062; the National Basic Research Program of China (973) under Grant No. 2009CB320705; the JiangSu Natural Science Foundation under Grant No. BK2011559. 10. REFERENCES [1] Y. Yao and J. Gehrke, “Query processing in sensor networks,” in CIDR, 2003. [2] S. Madden, M. J. Franklin, J. M. Hellerstein, and W. Hong, “Tag: A tiny aggregation service for ad-hoc sensor networks,” in Proceedings of OSDI, 2002. [3] S. Scott, R. Sylvia, K. Brad, G. Ramesh, and E. 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