The original PARSEC (PARametric SECtion) method can satisfactorily solve the optimization problems involving transonic airfoils by using a few design variables. However, it is difficult to apply this method to the design of airfoils under other conditions such as supersonic flow and low Reynolds number flow. To solve various airfoil design problems by using a few design variables and the PARSEC representation, a modified PARSEC representation is proposed. The capability of the proposed modified representation to solve unknown real-world design problems is investigated; the proposed representation is used along with multi-objective genetic algorithms to solve two types of problems. One is the design of a conventional transonic airfoil that i...