Abstract:  | 
                        We present an island model that uses different representations in each island. The model transforms individuals from one representation to  another during migrations. We show that such a model helps the  evolutionary algorithm to escape from local optima and to solve problems  that are difficult for single representation EAs. We illustrate this  approach with a two population island model in which one island uses a  standard binary encoding and the other island uses a standard reflective  Gray code. We compare the performance of this multi-representation  island model with single population EAs using only binary or Gray codes.  We show that, on a variety of difficult multi-modal test functions, the multi-representation island model does no worse than a standard EA on all of the functions, and produces significant improvements on a subset of them.   |