1. Faculty of Engineering, University of Miyazaki 1 , 1-1 Gakuen-Kibanadai-Nishi, Miyazaki 889-2192, Japan
2. Institute of Fluid Science, Tohoku University 2 , 2-1-1 Katahira, Aoba-ku Sendai-shi, Miyagi 980-8577, Japan
3. Department of Electrical and Computer Engineering, National Yang Ming Chiao Tung University 3 , Hsinchu 30010, Taiwan