1. Department of Chemical and Biological Engineering; Korea University; Seoul 136-701 South Korea
2. KU-KIST Graduate School of Converging Science and Technology; Korea University; Seoul 136-701 South Korea
3. School of Electrical Engineering; Korea University; Seoul 136-713 South Korea
4. New Transportation Systems Research Center; Korea Railroad Research Institute; Uiwang-City Gyeonggi-do 437-757 South Korea
5. Department of Civil; Environmental and Architectural Engineering; Korea University; Seoul 136-701 South Korea