1. a Department of Liberal Arts , Kanagawa Institute of Technology , Simo-ogino 1030, Atsugi , 243-02 , Japan
2. b Research Laboratory of Precision Machinery and Electronics , Tokyo Institute of Technology , Nagatsuta, Midori-ku, Yokohama , 221 , Japan
3. c Department of Metallurgical Engineering, Faculty of Engineering , Tokyo Institute of Technology , O-okayama, Meguro-ku, Tokyo , 153 , Japan