In Fig 7, the solutions of IBFOA densely distribute in the internal and optimal area of the radar chart, while the solutions of NSGAII and SPEA2 uniformly disperse in the outer edge of the chart. Therefore, the solutions of IBFOA are more Pareto optimal than those of NSGAII and SPEA2, in other words, NSGAII and SPEA2 are dominated by IBFOA, and those mean that the proposed IBFOA contributes to promoting the convergence of the algorithm as well as maintaining the diversity of the population.