Text and Data Mining valid from 2019-09-30
Received: 15 April 2019
Accepted: 7 May 2019
First Online: 30 September 2019
: <i>Conflict of interest:</i> Moonchu Foundation funded the project; none of the authors have any conflict of interest to declare
: <i>Ethical standards:</i> This article complies with the law. The study received an ethical approval from the institutional review board at The Hong Kong Polytechnic University with the reference number of HSEARS20161101002.