Funding for this research was provided by:
Ministry of Trade, Industry and Energy (10062269)
National Research Foundation of Korea (2012049647, 2019R1A2C1087653)
Text and Data Mining valid from 2020-03-10
Received: 29 October 2019
Accepted: 14 January 2020
First Online: 10 March 2020
: The authors declare that they have no competing interests.