1. Korea Testing & Research Institute, Key Industry Division, Jongga-ro 15, Ulsan, 44412, Korea
2. Kunsan National University, Department of Power System Engineering, Daehak-ro 558, Kunsan-si, Jeonbuk, Korea
3. Division of Marine Engineering, Mokpo National Maritime University, Haeyangdaehak-Ro 91 Mokpo-si, Jeonnam, 530-729 Korea