基金Supported by the Natural Science Foundation of China(No.10771228)the Natural Science Foundation of Chongqing(No.CSTC,2010BB2090)+1 种基金Education Commission project Research Foundation of Chongqing (No.KJ110617)Chongqing Key Laboratory of Operations Research and System Engineering(No.CSTC, 2006CA8001)
基金This work was supported by the National Natural Science Foundation of China (10471151)National 863 Project(2003AA148040)the Educational Science Foundation of Chongqing,Chongqing of China(041302).