An extension for grey cluster appraising method based on a ranking method of interval grey number

Grey cluster appraising method can classify the observed objects into clusters that classed prior to by decision-maker. The paper is the further extension of traditional grey cluster method by studying the determining problem of the turning-point of its whiten weight function. First, the paper introduces the method to establish the whiten weight function in grey cluster appraising model. Then, the paper puts forward the method to determine the turning-point of whiten weight function based on interval grey numbers to extend grey cluster appraising method, moreover develops a new ranking method for interval grey numbers based on mean and variance under the conditions of taking value information completely unknown for interval grey numbers. Last, the validity of our model is examined with an example. It is shown that the extended grey cluster appraising method developed by us is generalized and is more flexible in decision than the traditional grey cluster method.