Abstract: Based on the present theories of buffer operators and the back cumulative-sum method,this paper proposed a kind of buffer operators,which all have the universality and practicability. First, proved it to be weakening buffer operator,and at the same time,gave an example to illustrate our theory, which is very useful in qualitative analysis in some extent.

Key words: back cumulative-sum method, weakening buffer operator, forcasting and decision-making