Practical Applications of Data Mining

8.5 Fuzzy Query proCeSSIng 353

In this case, the relationship between the number of visitors and the

degree of membership is not linear, but a sine curve. The membership func-

tion F(x) can be defined with the following sine curve function with max =

1271, min = 216, and x = the number of visitors:

F

acceptable

(x) = 1/2 + 1/2 × sin [(1.5 + (x – min)/(max – min)) × p ( )]

Note that from the original definition of function sin(x), sin(0) = 0,

sin(p/2) = 1, sin(p ) = 0, and sin(3/2 × p ) = –1, etc. In representing the rela-

tionship between the degree of membership and the number of visitors, the

shape of the curve is the same ...