“…For the first goal, assigning different tasks to the sub-populations, there might be multiple small populations in P search searching for new solutions and there is only one large population in P track to track changing peaks [77], or there might be one large population to search and multiple sub-population for tracking changes [9,19,29,38,61,63,73], or each sub-population can both search for new solutions and track changes [39,57,58,104]. Relating to the goal of assigning the tasks to subpopulations, it should be noted that in dynamic optimization multiple populations are used not only for exploring different parts of the search space, but also for coevolution [40,73,75] or maintaining diversity and balancing between exploitation and exploration [110].…”