1. Department of Mechanical Engineering, Faculty of Engineering, Brawijaya University, Jl. MT Haryono 167, Malang 65145, Indonesia
2. Department of System Design Engineering, Keio University, 3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
3. Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan