1. Department of Electronic Engineering, Kumoh National Institute of Technology, Gumi, South Korea
2. Department of 2nd Sensor Division, i3system, Inc., Daejeon, South Korea
3. School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, South Korea
4. Department of Electrical and Computer Engineering, The University of Akron, Akron, OH, USA
5. Department of Otorhinolaryngology-Head and Neck Surgery, College of Medicine, Chungnam National University, Daejeon, South Korea