Funding for this research was provided by:
Ministry of Science, ICT & Future Planning of Korea (H-GUARD 2015M3A6B2063547)
Text and Data Mining valid from 2018-06-20
Received: 19 July 2017
Accepted: 8 January 2018
First Online: 20 June 2018
Compliance with ethical standards
: The authors declare that they have no conflict of interest.