Table 6.
Comprehensive summary including all models used in this study.
| Model | Type/description | Hyperparameters (used in this study) | Evaluation method | Notes/key points |
|---|---|---|---|---|
| Bayesian Ridge Regression (BRR) | Probabilistic linear regression with Bayesian L2 regularization | n_iter = 300, alpha_1 = 1e-6, alpha_2 = 1e-6, lambda_1 = 1e-6, lambda_2 = 1e-6, tol=1e-3, fit_intercept=True, normalize=False | LOOCV | Suitable for small datasets and correlated features; estimates regularization parameters automatically; provides predictive uncertainty. |
| Support Vector Regression (SVR) | Nonlinear regression using RBF kernel | kernel=’rbf’, C = 1.0, epsilon = 0.01 | LOOCV | Robust to outliers, handles nonlinear relationships; predictions may be combined in ensemble. |
| Random Forest Regression (RF) | Ensemble of decision trees averaging predictions | n_estimators = 100, max_depth = 3, min_samples_leaf = 2, random_state = 0 | LOOCV | Captures nonlinear relationships; shallow trees prevent overfitting small datasets; used in ensemble when ranked top. |
| Ensemble (Simple Average) | Combination of top 2 models | Equal weighting (0.5 each) of top 2 models based on RMSE | LOOCV predictions averaged | Combines strengths of different models; improves robustness and reduces errors compared to single models. |
| CNN+LSTM Hybrid Deep Learning | Convolutional + sequential model for capturing spatial and temporal dependencies |
Sliding window sequences: window_size = 3, step = 1 Conv1D: filters = 32, kernel_size = 2, activation=’relu’, L2 = 1e-4 LSTM: units = 32, L2 = 1e-4 Dense: units = 16, activation=’relu’, L2 = 1e-4 Dropout: 0.2 Optimizer: Adam loss=MSECallbacks: EarlyStopping (patience = 30), ReduceLROnPlateau (factor = 0.5, patience = 10, min_lr = 1e-6) |
5-fold Cross-Validation per material | Captures sequential patterns; combines convolution for spatial correlations and LSTM for temporal dependencies; features and targets scaled per fold; suitable for time-series-like input derived from sliding windows. |