1. Assistant Professor, Dept. of Transportation Technology and Management, Feng-Chia Univ., No. 100, Wenhwa Rd., Seatwen, Taichung, Taiwan 40724, R.O.C.
2. Graduate Student, Dept. of Transportation Technology and Management, Feng-Chia Univ., No. 100, Wenhwa Rd., Seatwen, Taichung, Taiwan 40724, R.O.C.