Early Drowsiness Detection via Second-Order Derivative Analysis of Heart Rate Variability: A Non-Contact ECG Approach with Machine Learning. - Vaussenat, Fabrice; Bhattacharya, Abhiroop; Payette, Julie; Saidi, Alireza; Bellemin, Victor; Renaud-Dumoulin, Geordi-Gabriel; Cloutier, Sylvain G.; Gagnon, Ghyslain (Sensors (14248220), 2026)