Funding for this research was provided by:
Guangdong Province Higher Vocational Colleges and Schools Pearl River Scholar Funded Scheme (2016)
shenzhen science and technology innovation committee (JCYJ20170817114522834)
Text and Data Mining valid from 2020-02-11
Received: 25 October 2019
Accepted: 26 January 2020
First Online: 11 February 2020
: The authors declare that they have no competing interests.