1. Robotics and Mechatronics Engineering, Daegu Gyeongbuk Institute of Science and Technology, Daegu 42988, Republic of Korea
2. School of Electrical Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
3. Department of Physics, Jeju National University, Jeju 63243, Republic of Korea
4. Department of Physics, Chungnam National University, Daejeon 34134, Republic of Korea