A modified ranking approach for solving fuzzy critical path problems with LR flat fuzzy numbers

There are several fuzzy critical path methods for solving fuzzy critical path problems in which ranking approaches are used for comparing fuzzy numbers. In this paper, it is shown that if the existing ranking approaches are used for solving such fuzzy critical path problems in which duration times of activities are represented by LR flat fuzzy numbers, then more than one fuzzy numbers, representing the fuzzy project completion time, are ob- tained and a new ranking approach for comparing LR flat fuzzy numbers is proposed. Also, it is proved that if the proposed rank- ing approach is used for solving fuzzy critical path problems then a unique fuzzy number, representing the fuzzy project completion time, is obtained.