1. Department of Automotive Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, South Korea e-mail:
2. Professor Department of Mechanical and Automotive Engineering, Keimyung University, 1095 Dalgubeol-daero, Daegu 704-701, South Korea e-mail:
3. Professor Department of Automotive Engineering, Hanyang University, 222 Wangsimni-ro, Seongdong-gu, Seoul 133-791, South Korea e-mail: