1. Nguyen Thi Duc Nguyen (Corresponding author), Research Organization of Science and Technology, Ritsumeikan University, 525-8577 Noji-higashi 1-1-1, Kusatsu Shiga, Japan.
2. Atsushi Aoyama, Graduate School of Technology Management, Ritsumeikan University 525-8577 Noji-higashi 1-1-1, Kusatsu Shiga, Japan.