Practical Applications of Data Mining

368 Chapter 8 Fuzzy InFormatIon retrIeval

Case 6: For C

2mean

< X < C

3mean

, Y = mX + b, where Y = degree of member-

ship, X = price, m = slope [(Y

2

-Y

1

)/(X

2

- X

1

)], b = Y-axis intercept, X

1

=

C

2mean

, Y

1

= 1, X

2

= C

3mean

, and Y

2

= 0.

The membership function for any attribute being concentrated is obtained

by combining all the membership functions covering each category of the

attribute values. In the book table, combining all the membership functions

representing all three categories (C

1

, C

2

, and C

3

) enables the formulation of the

complete fuzzy membership function of the attribute price as shown in Figure

8.17. This function covers a complete ...