Text and Data Mining valid from 2018-07-27
Received: 9 August 2017
Accepted: 9 July 2018
First Online: 27 July 2018
Compliance with Ethical Standards
: Author Soyoung Jung declares that she has no conflict of interest.Author Xiao Qin declares that he has no conflict of interest.Author Cheol Oh declares that he has no conflict of interest.