1. Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
2. Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521,
3. Faculty of Engineering, National University of Laos, Lao-Thai Road, Sokpaluang Village, Sisatanak District, Vientiane Capital, Laos