1. Department of Industrial Engineering and Management, National Taipei University of Technology, No. 1, Section 3, Chung-Hsiao East Road, Taipei, Taiwan
2. School of Commerce, Kainan University, No. 1, Kainan Road, Luchu, Taoyuan 338, Taiwan; Institute of Management of Technology, National Chiao Tung University, 1001, Ta-Hsueh Road, Hsinchu 300, Taiwan