Long, Feixiao http://orcid.org/0000-0001-7436-5844
Article History
Received: 28 July 2019
Accepted: 19 December 2019
First Online: 8 January 2020
Ethics approval and consent to participate
: Not applicable.
: No conflicts of interest, financial or otherwise are declared by the author. The author is affiliated with Hudongfeng Technology (Beijing) Co., Ltd. and the company played no role and gained nothing from the work.