Funding for this research was provided by:
National Research Foundation of Korea (NRF-2017R1A2B4006508)
Hallym University (HRF-201712-005)
Text and Data Mining valid from 2019-06-06
Received: 23 October 2018
Accepted: 20 May 2019
First Online: 6 June 2019
Ethics approval and consent to participate
: This study was approved by the Hallym University Institutional Review Board (HIRB-2017-030). Written consent was obtained from study participants.
: Not applicable.
: The authors declare that they have no competing interests.