1. a Department of Mechanical Engineering, National Taiwan University of Science and Technology , Taipei, Taiwan
2. b Department of Occupational Safety and Hygiene, Chang Jung Christian University , Kway Jen, Taiwan
3. c Institute of Occupational Safety and Health, Council of Labor Affairs, Shijr City , Taipei, Taiwan
4. d Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University , Taipei, Taiwan