1. Department of Mechanical Engineering, Graduate School, Kyung Hee University, Yong-in, Kyunggi-do, 446-701, Korea
2. School of Environment and Architecture, University of Shanghai for Science and Technology, Shanghai 20093, China
3. Department of Mechanical Engineering, College of Engineering, Kyung Hee University, Yong-in, Kyunggi-do, 446-701, Korea