Funding for this research was provided by:
National Research Foundation of Korea (Ministry of Education (2018R1D1A1B07048146), Korea Institute of Energy Technology Evaluation an)
Text and Data Mining valid from 2019-01-28
Received: 4 December 2018
Accepted: 12 January 2019
First Online: 28 January 2019
Compliance with Ethical Standards
: The authors declare no conflicts of interest.