Key Laboratory of Biomedical Engineering of Ministry of Education;
Department of Biomedical Engineering;
Zhejiang University;
'Hangzhou 310027;
China;
Department of Anaesthesia;
Women "s Hospital;
Hangzhou 310006;
China;
Institute of Space Medical Engineering;
Beijing 100094;
China;
Photoplethysmogram(PPG); Decay time constant; Non-iterative shape method(NSM); Area difference ratio(ADR);