In order to augment the dataset, for each instance in the training set we are creating an additional training instance by slightly perturbing the collision energy in all four spectra. In particular, each spectrum, out of the four spectra that are used to represent an instance in the dataset, is replaced with a spectrum that has the closest collision energy in the dataset with the spectrum to be replaced. In order to avoid large deviations from the preset energy levels (35% for low energy and 130% for high energy) we perturbed only the spectra that had exactly the pre-set energy levels (we recall here that in cases where a spectrum of 35% or 130% NCE was not available, it was already replaced with the closest available in the original dataset).