Achieving a perfect fit with an R-value of 1 indicates that the model reproduces the training data perfectly but does not guarantee good performance on unseen data. However, the performance of ANN needs to be evaluated based on the ability to predict unseen data. When the network performance is optimal at epoch 2, the corresponding R-value of the validation data set is 0.921, and the R-value of the test set is 0.884. Due to the network's initialisation and the training data's random partition, fitting results may exhibit slight variations.