a new approach of fuzzy numbers with different shapes and deviation

in this paper, we propose a new method for fuzzy numbers. in this method, we assume that ai= (ai1, ai2, ai3, ai4) is to be a fuzzy number. so, the convex combination of ai1 and ai2 and also the convex combination of ai3 and ai4 are obtained separately. then, mic and mis that are to be the convex combinations and the standard deviation respectively we acquire them from these components. finally, we can obtain ranking index (mi) that is the convex combination of, mic  and   mis. at the end of paper, in one example, the proposed method is compared with other methods.