To whom correspondence should be addressed. E-mail: mag@ ics. ict. ac. cnMa Gang , born in 1986. He is studying for a Ph. D degree in Computer Software and Theory in Insti- tute of Computing Technology, Chinese Academy of Sciences. He received his B.S. degree in Computer Science and Technology and M.S. degree in Computer Application Technology from China University of Min- ing and Technology in 2010 and 2013, respectively. His research interests include artificial intelligence, machine learning, deep learning and complex net- works.