Chul Ki Song is an Emeritus Professor in the School of Mechanical Engineering, Gyeongsang National University, Korea. He earned his Ph.D. degree from Seoul National University, Korea. He previously worked for KIA Motors.

Jong-Ryeol Kim is Professor in the Department of Electrical Engineering, Sejong University, Korea. He earned his Ph.D. degree from KAIST, Korea. He previously worked for Samsung Electronics.