Fig. 4

Schematic of the XGBoost model for training and learning. The balanced training set is used to learn the parameters in XGBoost model, and the validation set is used to optimize the hyperparameters of the model. Finally, the integrated model is used to test on the test set. In XGBoost model, CART is the base classifier, and the boosting strategy is adopted in the training process. By training a series of classifiers iteratively, the distribution of samples used by each classifier is related to the learning results of the previous round