“…In each entry in Table 2 , we listed the datasets, their descriptions, the preprocessing methods, the model names, and their results. Only the preprocessing methods that affected the input features or model structure were mentioned, and the reduction of noise for the PPG waveform signals (Multi-various kinds of algorithms were adopted [ 90 ], including an LMS filter [ 91 ], moving average filters [ 92 ], adaptive filters [ 93 , 94 ], the Kalman filter [ 95 , 96 ], IMAR [ 97 ], wavelet analysis [ 98 , 99 , 100 ], median analysis [ 101 , 102 , 103 ], and a notch filter [ 104 ].) were excluded.…”