supported by the National Natural Science Foundation of China (No. 60373012, 10871119);the Natural Science Foundation(No. ZR2009GM009, ZR2009AM013);the Promotional Foundation for Middle-aged or Young Scientists (No. BS2009DX024);the EDRP of Shandong Province (No. J10LG09)
Due to the limitation of energy resources, energy efficiency is a key issue in wireless sensor networks (WSNs). Clustering is proved to be an important way to realize hierarchical topology control, which can improve t...
Supported by NNSF of China (Grant No. 60373012);supported by NSFC (Grant No. 10601044);XJEDU2006S05
Let σk(G) denote the minimum degree sum of k independent vertices in G and α(G) denote the number of the vertices of a maximum independent set of G. In this paper we prove that if G is a 4-connected graph of ord...