“…Specifically, given a translated objective vector f ′ t,i in subpopulation j, the convergence criterion can be naturally represented by the distance from f ′ t,i to the ideal point 4 , i.e., ∥f ′ t,i ∥; and the diversity criterion is represented by the acute angle between f ′ t,i and v t,j , i.e., θ t,i,j , as the inverse function value of cos θ t,i,j calculated in (6). In order to balance between the convergence criterion ∥f ′ t,i ∥ and the diversity criterion θ t,i,j , a scalarization approach, i.e., the angle-penalized distance (APD) is proposed as follows: …”