Uncertainty quantification in water quality prediction using Optuna-optimized machine learning: A case study in the Quan Lo-Phung Hiep irrigation system, Vietnamese Mekong Delta - Huong Pham Thi; Phong Nguyen Thanh; Vuong Nguyen Dinh; Pham Truong; Duong Tran Anh; Ngoc Anh Le; Thai Son Mai; Song Pham Van; Tuan B.H. Nguyen; Pham Van Tung (Journal of Water Process Engineering, 2026)