1. Department of Biomedical Electronics, Songho College, 66 Namsanri, Hoengseong-gun, Gangwon 225-704, Republic of Korea
2. Engineering Research Institute, Gyeongsang National University, 501 Jinju-daero, Jinju, Gyeongsangnam-do 660-701, Republic of Korea
3. Department of Informatics, Gyeongsang National University, 501 Jinju-daero, Jinju, Gyeongsangnam-do 660-701, Republic of Korea