Funding for this research was provided by:
National High Technology Research and Development Program of China (2007AA01Z334)
National Natural Science Foundation of China (61321491, 61272219)
Innovation Fund of State Key Laboratory for Novel Software Technology (ZZKT2013A12, ZZKT2016A11)
Program for New Century Excellent Talents in University of China (NCET-04-04605)
Nanjing University Innovation and Creative Program for PhD candidate (2016013)
Article History
Received: 9 November 2017
Revised: 3 April 2018
Accepted: 16 May 2018
First Online: 16 June 2018