1. Interdisciplinary Department for Advanced Innovative Manufacturing Engineering, Pusan Natl. Univ., Busan, 46241, Korea
2. Department of Optics and Mechatronics Engineering, Pusan Natl. Univ., Busan, 46241, Korea
3. Department of Cogno-Mechatronics Engineering, Pusan Natl. Univ., Busan, 46241, Korea
4. Department of Mechanical and Industrial Engineering, Univ. of Massachusetts, Amherst, MA 01003, USA