Average Inheritance Usage Ratio (AIUR)

Description:

we define AIUR for a derived class as the average value of the IUR metric computed between that class and all its ancestor classes.

for class C, let the set of its ancestor be {A_i}, (i=1, NOA):

	NOA
		IUR(C, Ai)
	i=1
AIUR =
	NOA

where NOA is the number of ancestor classes for class C.