Funding for this research was provided by:
National Natural Science Foundation of China (No. 81373531)
National Social Science Foundation of China (No. 17BXW071)
Technology Program of Lanzhou Science and Technology Bureau (No.214162)
SWPU Innovation Team “Data Intelligence” Funding (No. 2015CXTD06)
Article History
Received: 3 October 2017
Accepted: 6 September 2018
First Online: 14 September 2018
Compliance with ethical standards
:
: We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.