Geng Xiutang was born in 1975. He obtained the B. S. degree in technics and equipment of machine from Dalian Jiaotong University, China, in 1999 and the M. S. degree in system engineering from Northwestern Polytechnical University, China, in 2004, respectively. Nowadays, he is a candidate doctor in system engineering from Huazhong University of Science and Technology, in China. His fields of interest are soft computing, aviation electron, system modeling and optimization, DNA computing and so on. E-mail: gxt1028@163.com Zhang Kai was born in 1979. He received M. S. degree in computer from Wuhan University of Science and Technology, 2005. He is currently working towards the Ph.D. degree in system optimization theory and system engineering from Huazhong University of Science and Technology. His current research interests include graph theory and operational research. E-mail: zhangkaicn@smail.hust.edu.cn