Funding for this research was provided by:
National Research Foundation of Korea (2017R1A2B1005363)
Hankuk University of Foreign Studies
National Research Foundation of Korea (2016R1C1B1009808, 2015R1A5A1009350)
Ministry of Trade, Industry and Energy (10048720)
IITP (B0717-16-0107)
National Research Foundation of Korea (2014R1A2A1A10050531)
Article History
Received: 7 December 2017
Revised: 16 April 2018
Accepted: 14 May 2018
First Online: 5 June 2018