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Terminology

  • Model: Representation of the learned patterns in the data. It is the output of the training process and can be used to make predictions on new data. In mathematical terms, y = f(x), f is the model.
  • Generalization: The ability of a model to perform well on unseen data rather than only on its training data. Good generalization allows a model to make accurate predictions on new examples.
  • Training set: A dataset used to train a machine learning model. It contains input-output pairs that the model learns from.
  • Validation set: A dataset used to evaluate the model's performance during training. It helps in tuning hyperparameters and preventing overfitting.
  • Test set: A dataset used to assess the final performance of the trained model. We never train on the test set. It should be separate from the training and validation sets to provide an unbiased evaluation for generalization
  • Hyperparameters: Parameters that are set before training a model, such as learning rate, batch size, and number of layers. They control the training process and model architecture.
  • Epoch: One complete pass through the entire training dataset.
  • Learning rate: A hyperparameter that controls the step size at each iteration while moving toward a minimum of a loss function. It determines how large the steps are in the direction of the gradient. During training, we keep typical learning rates whereas while fine-tuning we use smaller learning rates to avoid destroying the pre-trained weights.
  • Hidden layers: Layers in a neural network that are not directly connected to the input or output.
  • K-fold cross-validation: A technique used to assess model performance by splitting the dataset into (K) subsets, called folds. The model is trained on (K-1) folds and validated on the remaining fold. This process is repeated (K) times, with each fold serving as the validation set once. The final performance metric is averaged across all (K) runs. The model is therefore trained (K) times, or (K+1) times if a final model is subsequently trained on the entire training dataset.