fig9

Figure 9. Five-fold cross-validation average prediction accuracy. (A) Comparison of prediction results between the Stacking model and other common proxy models; (B) Comparison of prediction results among the Stacking model, the base models, and the meta-model. E_C: Carbon emissions; T_S: tensile strength; I_W: weld depth-to-width ratio; ELM: extreme learning machine; PSO-BP: particle swarm optimization - back propagation; RBF: radial basis function; MLP: multi-layer perceptron; XGBoost: extreme gradient boosting; SVR: support vector regression; RF: random forest; KRG: Kriging.