thesis - Faculty of Information and Communication Technologies ...

Chapter 6. Change Dynamics
50.0%
45.0%
40.0%
35.0%
30.0%
% Types
25.0%
20.0%
All
Modified
New
15.0%
10.0%
5.0%
0.0%
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 37 39 41
RSN
Figure 6.7: Spring In-Degree Count evolution. Proportion of modified
classes with high In-Degree Count is greater than that of new or all
classes.
We observed the following property (Equation 6.2.13) holds, for 90% of
the releases in our data set:
c p v > p v (6.2.13)
Interestingly, even if we include all of the data, that is, we consider releases
where less than 30 classes have been modified, the above property
hold approximately 75% of the time.
Although, this property holds across all releases, are individual systems
different? Does this property get violated more in some systems?
In order to answer this question, we investigated each system. We observed
that in 3 systems (Proguard, Tapestry and Acegi), this property
holds only 50% of the time. These systems appear to be outliers (all
other systems in our data set had at least an 80% probability). Interestingly,
in 17 systems, the property holds 100% of the time. That is,
in these systems, the majority of modified classes are popular.
158