An analysis of accuracy-diversity trade-off for hybrid combined system with multiobjective predictor selection

摘要

This study examines the contribution of diversity under a multi-objective context for the promotion of learners in an evolutionary system that generates combinations of partially trained learners. The examined system uses a grammar-driven genetic programming to evolve hierarchical, multi-component combinations of multilayer perceptrons and support vector machines for regression. Two advances are studied. First, a ranking formula is developed for the selection probability of the base learners. This formula incorporates both a diversity measure and the performance of learners, and it is tried over a series of artificial and real-world problems. Results show that when the diversity of a learner is incorporated with equal weights to the learner performance in the evolutionary selection process, the system is able to provide statistically significantly better generalization. The second advance examined is a substitution phase for learners that are over-dominated, under a multi-objective Pareto domination assessment scheme. Results here show that the substitution does not improve significantly the system performance, thus the exclusion of very weak learners, is not a compelling task for the examined framework.