“…A population trapped at the optimum usually has limited diversity and limited ability to find another, possibly better, optimum. Many strategies of regaining population diversity have been proposed: crowding (DeJong, 1975;Mengshoel and Goldberg, 2008;Kowalczuk and Białaszewski, 2006), fitness sharing (Goldberg and Richardson, 1987;Sareni and Krähenbühl, 1998) and spatially structured populations (Tomassini, 2005;Dick and Whigham, 2006) are the most popular. In order to preserve diversity, hybrid methods combine different optimization strategies at various stages of the search process (Grosan and Abraham, 2007;Barabasz et al, 2014).…”