1. a Institute of Preventive Medicine, National Defense Medical Center, PO Box 90048-700, Sanhsia, Taipei 237, Taiwan, ROC
2. b Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
3. c Biomedical Engineering Program, Graduate Institute of Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC
4. d Institute of Preventive Medicine, National Defense Medical Center, PO Box 90048-700, Sanhsia, Taipei 237, Taiwan, ROC
5. e Institute of Preventive Medicine, National Defense Medical Center, PO Box 90048-700, Sanhsia, Taipei 237, Taiwan, ROC
6. f Institute of Preventive Medicine, National Defense Medical Center, PO Box 90048-700, Sanhsia, Taipei 237, Taiwan, ROC. jjyoung@ms49.hinet.net
7. g Graduate Institute of Biomedical Engineering, National Taiwan University of Science and Technology, Taipei, Taiwan, ROC