1. Department of Industrial Engineering and Management, National Chin-Yi Univ. of Technology, Taichung 41170, TW.
2. Department of Industrial Management, National Taiwan Univ. of Science and Technology, Taipei 10607, TW.
3. Department of Industrial Management, National Taiwan Univ. of Science and Technology, Taipei 10607, TW, (Corresponding author), e-mail: pigsmallchang@gmail.com