1. Graduate School of Engineering, Nagasaki University, 1-14 Bunkyo-machi, Nagasaki 852-8521, Japan
2. R&D Division, Kyowakiden Industry Company, Ltd., 10-2 Kawaguchi-machi, Nagasaki 852-8108, Japan
3. Ingram School of Engineering, Texas State University, 601 University Drive, San Marcos, Texas 78666-4684, United States