1. Department of Biomedical Engineering, College of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
2. Department of Electronic Engineering, Kyung Hee University, Gyeonggi-do 17104, Republic of Korea
3. Department of Obstetrics & Gynecology, Uijeongbu St Mary’s Hospital, College of Medicine, The Catholic University of Korea, Gyeonggi-do 11765, Republic of Korea