Funding for this research was provided by:
Incheon National University
National Research Foundation of Korea (NRF-2017R1C1B5017328)
Received: 15 August 2018
Accepted: 11 July 2019
First Online: 23 July 2019
Ethics approval and consent to participate
: Not applicable.
: None of the authors of this paper had a financial or personal relationship with other people or organizations that could inappropriately influence or bias the content of the paper. The opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of the institutions with which the authors are affiliated.