“…Quantitative features, which portray underlying characteristics and behaviors associated with physiological and clinical states, are subsequently obtained. A variety of quantitative features including time-domain features [25][26][27][28][29][30][31][32][33], frequency-domain features [13,26,29,[30][31][32][34][35][36][37], and nonlinear features [13,26,[29][30][31][34][35][36][37] are extracted from EHG data and applied for EHG data processing. Quantitative features are extracted from EHG signals through wavelet transforms, that is, DWT and wavelet packet, and applied for preterm birth classification [26,38,39] and labor classification [13,34,40].…”