 One way to fix this difficulty is to relax the constraint formula_55 for values of formula_22 outside the set formula_62 in a controlled manner so that larger violations are allowed as the distance of formula_22 from formula_62 increases.For instance, consider the relaxed robustness constraint

where formula_77 is a control parameter and formula_78 denotes the distance of formula_22 from formula_62.Thus, for formula_81 the relaxed robustness constraint reduces back to the original robustness constraint.