“…In the 1990 s, many researchers studied the grey system theory and its applications. These include the grey relational analysis (Huang and Huang, 1996;Huang and Chu, 1999), the grey linear programming approach (Huang et al, 1992(Huang et al, , 1993(Huang et al, , 1994(Huang et al, , 1995, and the grey prediction theory Huang, 1996, 1997;Chen and Jou, 2000;Wang, 2002;Lee and Wang, 1998;Xia and Hu, 1997a). Recently, grey correlation evaluation methods and their applications have been developed by Xia and Hu (1997b); Xia (1995).…”