Funding for this research was provided by:
Ministry of Education (NRF-2017R1A2A2A05001217, NRF-2017R1C1B2007258)
Text and Data Mining valid from 2020-01-10
Received: 3 July 2019
Accepted: 30 December 2019
First Online: 10 January 2020
Ethics approval and consent to participate
: Not applicable. Institutional Review Board approval was not required because of the nature of our study, which was a study based on research articles.
: Not applicable. There are no details on individuals reported within the manuscript, so we don’t have the consent for publication.
: The authors declare that they have no competing interests.