mathematical model Article 7 human 7 Humans 5 machine learning 4 signal noise ratio 4 adult 3 electrocardiography 3 electroencephalography 3 female 3 heart rate 3 human experiment 3 male 3 nerve cell network 3 normal human 3 physical activity 3 Electrocardiography 2 Walking 2 Wearable Electronic Devices 2 Wearable sensors 2 Wrist 2 algorithm 2 artificial neural network 2 breathing 2 breathing rate 2 classification algorithm 2 comparative effectiveness 2 electrocardiogram 2 electromyography 2 electronic device 2