1. Principle Researcher, Transport Systems Research Team, Korea Railroad Research Institute, 176 Cheoldobangmulgwan-ro, Uiwang-si, Gyeonggi-do 16105, Korea. ORCID: .
2. Assistant Professor, Dept. of Industrial Management and Engineering, Myongji Univ., 116 Myongji-ro, Cheoin-gu, Yongin-si, Gyeonggi-do 17058, Korea (corresponding author). ORCID: .