作者机构:[1]Network Research Center of Tsinghua University, Beijing 100084, P. R. China, [2]School of Economics & Management, Chongqing Normal University Chong qing, P. R. China
相关基金:Acknowledgment This work is supported by grants from the National Natural Science Foundation of China (Grant No. 60203044, 90412010), China 863 Project #2008BAH37B04 and Chongqing Science & Technology Commission Project (CSTC2011AC2143).