ASSESSING THE PREDICTIVE PERFORMANCE OF ARTIFICIAL NEURAL NETWORK-BASED CLASSIFIERS BASED ON DIFFERENT DATA PREPROCESSING METHODS, DISTRIBUTIONS AND TRAINING MECHANISMS

摘要

We analyse the implications of three different factors (preprocessing method, data distribution and training mechanism) on the classification performance of artificial neural networks (ANNs). We use three preprocessing approaches: no preprocessing, division by the maximum absolute values and normalization. We study the implications of input data distributions by using five datasets with different distributions: the real data, uniform, normal, logistic and Laplace distributions. We test two training mechanisms: one belonging to the gradient-descent techniques, improved by a retraining procedure, and the other is a genetic algorithm (GA), which is based on the principles of natural evolution. The results show statistically significant influences of all individual and combined factors on both training and testing performances. A major difference with other related studies is the fact that for both training mechanisms we train the network using as starting solution the one obtained when constructing the network architecture. In other words we use a hybrid approach by refining a previously obtained solution. We found that when the starting solution has relatively low accuracy rates (80-90%) the GA clearly outperformed the retraining procedure, whereas the difference was smaller to non-existent when the starting solution had relatively high accuracy rates (95-98%). As reported in other studies, we found little to no evidence of crossover operator influence on the GA performance.