Ranking members of sets with uncertain center by using general type-2 fuzzy membership values

In this paper a new method is proposed for ranking members of the set with uncertainty in the center of set. It means that the set´s center is considered as multi objects rather that single object. The degree of belonging to the set is defined based on general type-2 fuzzy membership values which the primary variable indicates the closeness to the each center; and the secondary variable indicates the center position compared to other central objects in the set. Then, the centroid approached is applied for ranking the general type-2 membership values. The performance of the model is demonstrated by applying on a numerical example and results are compared with ranking list based on type-1 fuzzy membership values.