Practical Applications of Data Mining

2.4 assoCiation rules in hypertext DataBases 49

Now, let’s consider the weighted directed graph in Figure 2.14. Let the

rule r be (B → C → D). Then

C

(B→C→D)

=

3

31+

×

2

21+

= 0.5 and S

(B→C→D)

=

32

2

21

12

+

= 1.43.

With an appropriate support value, we can capture rules that are globally

frequent, but the rules may contain some links that are below the support

threshold. From the trail B

3

→

C

2

→

D

2

→

E

1

→

F in the example in

Figure 2.14, we get

S

r

==

.

.

8

4

175

114

Note in this case that the minimum support value among all the single

rules constituting the composite rule is 0.57 since S

B→C

=

3

175.

= 1.71,

S

C→D

=

2

175.

= 1.14, S

D→E

=

2

175.

= 1.14, ...