Funding for this research was provided by:
National Natural Science Foundation of China (11701333)
Support Program for Outstanding Young Scientific and Technological Top-notch Talents of College of Mathematics and Systems Science (Sxy2016K01)
Text and Data Mining valid from 2019-10-16
Received: 25 April 2019
Accepted: 9 October 2019
First Online: 16 October 2019
: The author declares to have no competing interests.