A new method for computing grey relational grade

The mean method for computing gray relational grade(GRG) may obliterate information of the specific characteristics of gray coefficients and possibly make a mistake in judgement of the order relationship with whole approximation. The concepts of a perfect sequence, an opposite sequence, a near distance and a far distance are introduced. The relationship among the near distance and the far distance, and the correlative properties of a sequence is studied, and the relative propositions are presented. Norm gray relational grade (NGRG) is put forward based on the conception of norm, and its properties are discussed. Compared with the original GRG, the NGRG has a integrated approximation and can express the specific characteristics of gray relational coefficients.