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Combining Integreted Sampling Technique with
Feature Selection for Software Defect Prediction
Sukmawati Anggraeni Putri
STMIK Nusa Mandiri, Information System Program
Jakarta, Indonesia
sukmawati@nusamandiri.ac.id
Frieyadie
AMIK BSI Jakarta, Management Informatic Program
Jakarta, Indonesia
frieyadie@bsi.ac.id
Abstract—Good quality software is a supporting factor that is
important in any line of work in of society. But the software
component defective or damaged resulting in reduced
performance of the work, and can increase the cost of
development and maintenance. An accurate prediction on
software module prone defects as part of efforts to reduce the
increasing cost of development and maintenance of software. An
accurate prediction on software module prone defects as part of
efforts to reduce the increasing cost of development and
maintenance of software. From the results of these studies are
known, there are two problems that can decrease performance
prediction of classifiers such imbalances in the distribution of the
class and irrelevant of the attributes that exist in the dataset. So
as to handle both of these issues, we conducted this research
using integrated a sample technique with feature selection
method. Based on research done previously, there are two
methods of samples including random under sampling and
SMOTE for random over sampling. While on feature selection
method such as chi square, information gain and relief methods.
After doing the research process, integration SMOTE technique
with relief method used on Naïve Bayes classifiers, the result of
the predicted value better than any other method that is 82%.
Keywords—imbalance class, feature selection, software defect
prediction
I. INTRODUCTION
In the development of the use of software to support the
activities and the work increases, certainly the quality of the
software must be considered. But the software component
defective or damaged resulting in a decrease in customer
satisfaction, as well as an increase in the cost of development
and maintenance [1].
An accurate prediction on software module software
defects as part of effort to reduce the increasing cost of
development and maintenance of software that has been done
by previous researchers [2]. In this study focuses on 1)
estimating the amount of defect in the software, 2) find the
relationship of software defects, 3) classifying defect software
components, which defect module and non defect module [3].
While the software defect prediction research that has been
done by previous research such as Naïve Bayes classifier [4]
produce a good performance with an average probability of
71%. Naïve Bayesian is a simple classification [5] with a time
of learning process is faster than any other machine learning
[4]. Additionally it has a good reputation on the accuracy of
prediction [6]. However, this method is not optimal in the case
of having an unbalanced dataset [7].
The predicted performance of this method gets worse when
the dataset has an irrelevant attribute [8]. While NASA MPD
dataset [9] which have been used by previous researchers on
software predictions have unbalanced defect datasets with
attributes that are not all usable. To deal with unbalanced
datasets there are three approaches that can be used, including
data level (sample technique), algorithm level and ensamble
method [10].
In general, the sample technique is divided into two types,
including over sampling method is Random Over Sampling
[11]. While the under sampling method is Random Under
Sampling [12] and Resample method [13].
As for solving the problem of attributes that are irrelevant
using attribute selection methods such as Information Gain,
Chi Square, and Relief [14].
In this study, we propose to integrate the sample technique
with feature selection method to handle imbalance class and
attribute irrelevant to the Naïve Bayesian classification to
produce a better accuracy in the software defect prediction.
There are several steps done in this study, First, sample
technique to handle the imbalance class. Then, approaching the
selection attributes thrown clasifiying for software defect
predicition. Then calculating the validation and evaluation
technique to determine the proposed method is wheter it better
or not with the existing methods.
II. RELATED WORK
Research on the software defect prediction are one of the
research that has been done by previous researches. From these
studies it is known state of the art about software defect
prediction research that discusses the imbalance class.
As research done by Chawla [15] who proposed the use of
Synthetic Minority Oversampling Technique to handle the
class imbalance by using a Naïve Bayesian classifier,
2017 5TH INTERNATIONAL CONFERENCE ON CYBER AND IT SERVICE MANAGEMENT (CITSM)
978-1-5386-2739-6 @2017 IEEE
10.1109/CITSM.2017.8089264
implemented in eight different dataset from the UCI repository.
The results showed for all the data using SMOTE technique on
balancing process has a greater potential to improve the
performance of Naïve Bayesian and C.45 classifier use in the
classification process.
While the research done by Riquelme [13] which states that
the dataset in software engineering is very unbalanced.
Therefore to balance using two technique, including SMOTE
and Weka Randomly Resampling using J48 and Naïve
Bayesian classifier is applied to the five datasets form
PROMISE repository. The results show the approach SMOTE
able to increase the average AUC value of 11.6%. Based on
these results, balancing techniques can better classify minority
classes.
While the research done by Putri, Wahono [16] states that
NASA MDP dataset has unbalanced classes and attribute not
relevant. Using the balancing class SMOTE and feature
selection information gain, can improve the prediction results
are better than Riquelme research only to rebalance the dataset
class.
Furthermore the study done by Gao using one of the feature
selection algorithm which Relief that have been used in the
research done by Kira. The research Gao shows that the Relief
method as well as the Information Gain [17].
Therefore in this study implement an approach sample
techniques which Synthetic Minority Over-sampling
Technique (SMOTE) to reduce the influence of class
imbalance and improve the ability to predict the minority class.
Relief algorithm as well as for selection the relevant attribute.
It also use Naïve Bayes algorithm used in the classification
process.
III. METHODE
3.1. Sample Technique
The sample approach is one approach to solve the
problem of class imbalance in a dataset. The commonly used
sample approaches are over-sampling and under-sampling
techniques [10].
a. Over-Sampling Technique
Over-sampling causes excessive duplication in the
positive class cause over-fitting. Moreover, over-sampling
can increase the number of training dataset, thus causing
excessive computational costs [15].
Nevertheless, in research carried out by Chawla [15]
found Synthetic Minority Over-sampling Technique
(SMOTE) which produces artificially interpolated data on the
over-sampling in the minority. The algorithm is simulated by
finding k nearest to each minority sample, and then for each
neighbor, randomly pick a point on the line connecting
neighbors and sample itself. Finally, the data at that point is
entered as an example of the new minority. By adding new
minority sample into training data, is expected to over-fitting
can be resolved [15].
b. Under-sampling Technique
Under-sampling approaches have been reported to
outperform over-sampling approaches in previous literatures.
However, the under-sampling approach reduces the majority
class, perhaps losing useful information. This results in less
accurate predictions [11].
Sampling is done randomly, so the majority of the
sample is as large as the number of minority samples.
Meanwhile, the sample used in the under-skilled approach is
the majority sample that is under the sample [18] .
We implemented our proposed Random Under-
Sampling and SMOTE in the WEKA tool.
3.2. Feature Selection
At dataset software defects, attributes represent software
metrics taken from the source code of the software used in the
learning process. However, some attributes that are not
relevant to require the removal to improve the accuracy of
software defects prediction.
There are two algorithms used in the selection of attributes
that wrapper and a filter [17]. In the wrapper algorithm using
feedback from learning algorithm. While on the filter
algorithm, the training data are analyzed using methods that
do not require learning algorithms to determine the most
relevant attributes [17]. In this study only uses algorithms to
filter the selection attribute. Such as, chi-square (CS),
information gain (IG), and Relief algorithm (RLF) [17].
a. Chi Square (CS)
CS can evaluate attribute values by calculating the
statistical value related to the class. Statistical CS (also
symbolized as 𝜒2) is a nonparametric statistical techniques by
using nominal data (category) with the test frequency.
(1)
where 𝜒2 is the test statistic is asymptotically approaching the
𝜒2 distribution, Oi is the observed frequencies, and Ei is the
expected frequency. n is the number of possible outcomes of
each event.
b. Information Gain (IG)
In the IG is able to assess the importance atibut by
measuring the information gain associated with the class.
Generally IG estimates that the change in entropy of
information before the state took some information.
IG (Class,Attribute)=H(Class)−H(Class|Attribute) (2)
where H determine entropy. More specifically, suppose
that A is the set of all attributes and class attributes being
dependent of all the training examples, the value of (a, y)
with y ∈ Class defines the value of specific examples to
attribute a ∈ A, V is the set of attribute values, namely V =
{value (a, y) | a ∈ A ∩ y ∈ Class} and | s | is the number of
elements in the set s. G to attribute a∈. A defined as
follows:
(3)
c. Relief (RLF)
For a given sample R, Relief find the nearest neighbor of
the same class or different, which is called the 'nearest hit H'
and 'nearest miss M'. It will be updated estimate of the quality
of W [A] for all attributes A depending on their values for R,
F, and H. The process is repeated in accordance with the
value of m, where m is determined by the user. Diff function
(Attribute, Instance1, Instance2) clearly defined in
accordance with the type attribute. For discrate attributes are
defined as follows:
(4)
The underlying hypothesis is that the relevant attributes are
able to distinguish between things of different classes and
showed no difference between instances of the same class.
3.3. Naive Bayesian (NB) Classifier
Naïve Bayes assumes that the impact of a certain
class attribute value is independent of the values of other
attributes. This assumption is called the independent class
conditional. This is done to simplify the calculation involved,
and in this sense it is considered naive. Naïve Bayes allows
representation of dependencies among a subset of attributes
[19]. By mathematical calculation as follows:
(5)
The probability P(X1|C1), P(X2|Cj), …, P(Xn|Ci) can be easily
estimated from the training set. Given that Xk refers to the
attribute values for the sample X.
a. If Ak is a category, then P(Xk|Cj) is number of tuples in D
class Cj has a value Xk to attribute Ak, divided from |C1,D|,
number of class Cj tuples in D.
b. If Ak is a continuous value, it is usually assumed that
the values have a Gaussian distribution with mean (μ) and
standard deviation (σ), can be defined as follows:
(6)
While
(7)
We need to calculate and , where the mean and
standard deviation of the value attribute Ak for training
samples of class Cj.
3.4. Validation Technique
In this study using validation techniques 10 fold cross
validation, with resulting confusion matrix [20] which are
described in Table 1. In the confusion matrix, TN is true
negative results are classified (true negative). FN is a positive
result that is not properly classified as negative. TP is a
positive result correctly classified (true positive). FP is the
negative results are not correctly classified as positive (false
positive). TABLE 1.
CONFUSION MATRIX
Confusion matrix of values will produce the ROC curve
(Receive Operationg Characteristics) whose task is to
evaluate the performance of the classifier algorithm. Then the
Area Under the ROC as a reference for evaluating which
provides a summary of the performance of the classifier
algorithm [20]. Area Under the ROC (Receive Operating
Characteristic) (AUC) is a single value measurements are
derived from signal detection. AUC values range from 0 to 1.
The ROC curve is used to characterize the trade-offs between
true positive rate (TPR) and false positive rate (FPR). A
classifier that provides a large area under the curve is more of
a classifier with a smaller area under the curve [21].
3.5. Evaluation Technique
In the statistical evaluation consisted of testing
parametric and non-parametric test. As for testing the
significant difference of the classifier algorithm performance
using the non-parametric tests, such as tests friedman [22].
Friedman test is a non-parametric test that is equivalent
to the ANOVA parametric test. In the Friedman test ranking
algorithm for each data set separately, the algorithm
performance is good to be ranked first, while for the second-
best given. Friedman test carried out by the appropriate post
hoc test for comparison of more than one classifier with
multiple datasets [22].
Below will be shown on the test friedman formula:
(8)
Where
= khai value - the level of two-way squares friedman
N = amout of sample
K = the number of groups samples
1, 3, 12 = constanta
Class
Initial Value
True
False
Predicition
Value
True
TP
FP
False
FN
TN
IV. EXPERIMENT RESULT
4.1. Dataset
In this study, using a dataset of software metric (National
Aeronautics and Space Administration) MDP repository. They
are public datasets used by previous researchers in the field of
software defects prediction. NASA dataset MDP can be
obtained via the official website Wikispaces (http://nasa-
softwaredefectdatasets.wikispaces.com/). Dateset used in this
study consisted of CM1, MW1, PC1 and PC4 are described in
Table 2.
TABLE 2.
NASA MDP DATASET
As shown in Table 2, that each dataset consists of several
software modules, along with the number of errors and
attributes characteristic code. NASA dataset preprocessing
MDP has 38 attributes plus one attribute disabled or not
disabled (defective?). The attribute consists of an attribute type
Halstead, McCabe, Line of Code (LOC) and miscellaneous
attributes [23].
The dataset was obtained from NASA MDP software
matrices which are described in Table 3, as follows:
TABLE 3.
SPECIFICATIONS AND ATTRIBUTES NASA MDP
4.2. Implementation and Experiment Results
In this study using Naive Bayesian classifier algorithm at 4
dateset NASA MDP (CM1, MW1. PC1 and PC4). Classifier
algorithm will be applied on the integration sample technique
with a selection attribute method. Like, NB classifier with
SMOTE and CS, NB classifier with SMOTE and IG, NB
classifier with SMOTE and RLF, NB classifier with RUS +
CS, NB classifier with RUS and IG, and NB classifier with
RUS and RLF.
TABLE 4.
AUC VALUE
Clasification
CM1
MW1
PC1
PC4
NB
0,694
0,727
0,768
0,825
NB with SMOTE and
CS
0,766
0,759
0,734
0,856
NB with RUS and CS
0,752
0,722
0,79
0,859
NB with SMOTE and
IG
0,751
0,767
0,817
0,856
NB with RUS and IG
0,753
0,722
0,79
0,859
NB with SMOTE and
RLF
0,761
0,779
0,821
0,86
NB with RUS and
RLF
0,755
0,747
0,793
0,878
In Table 4 shows the results AUC values were well on the
use of models NB with SMOTE and RLF on two datasets
(MW1, PC1). As for the CM1 dataset shows AUC good value
on NB with SMOTE and CS models. And for PC4 dataset
shows AUC good value on NB with RUS and RLF model.
4.3. Comparison Between Previous Models
To know that the proposed model has increased the
accuracy after the optimized use of integration between
sampling technique and feature selection algorithm, then do a
comparison between the proposed model and a model that has
been proposed by Menzies [4], Requilme [13] and Putri [24].
NASA MDP Dataset
CM1
MW1
PC1
PC4
LOC
Count
LOC_total
X
X
X
X
LOC_blank
X
X
X
X
LOC_code_and_com
ment
X
X
X
X
LOC_comment
X
X
X
X
LOC_executable
X
X
X
X
Number_of_lines
X
X
X
X
Halstead
Attributes
Content
X
X
X
X
Difficulity
X
X
X
X
Effort
X
X
X
X
Error_est
X
X
X
X
Length
X
X
X
X
Level
X
X
X
X
Prog_time
X
X
X
X
Volume
X
X
X
X
Num_operands
X
X
X
X
Num_operators
X
X
X
X
Num_unique_operan
ds
X
X
X
X
Num_unique_operat
ors
X
X
X
X
McCabe
Attriutes
Cyclomatic_complex
ity
X
X
X
X
Cyclomatic_density
X
X
X
X
Design_complexity
X
X
X
X
Essential_complexity
X
X
X
X
Miscellan
eous
Attributes
(another)
Branch_count
X
X
X
X
Call_pairs
X
X
X
X
Condition_count
X
X
X
X
Decision_count
X
X
X
X
Decision_density
X
X
X
X
Design_density
X
X
X
X
Edge_count
X
X
X
X
Essential_density
X
X
X
X
Parameter_count
X
X
X
X
Maitenance_severity
X
X
X
X
Modified_condition_
count
X
X
X
X
Multiple_condition_
count
X
X
X
X
Global_data_comple
xity
Global_data_density
Normalized_cycloma
tic_compl
X
X
X
X
Precent_comments
X
X
X
X
Node_count
X
X
X
X
Number of code attribute
37
37
37
37
Number of Modul
342
266
759
1399
Number of defect modul
41
28
61
178
System
Language
Program
Dataset
LOC
Instruments a spacecraft
C
CM1
17K
Database
C
MW1
8K
Flight software for satellites
orbiting the Earth
C
PC1
26K
PC4
30K
TABLE 5.
AUC OF COMPARISON BETWEEN PREVIOUS MODELS
Model
CM1
MW1
PC1
PC4
Menzies (2011), NB
0,694
0,727
0,768
0,825
Requilme (2008), NB with SMOTE
0,739
0,751
0,793
0,858
Putri, Wahono (2015), NB with
SMOTE and IG
0,751
0,767
0,817
0,856
Propose Model, NB with SMOTE
and RLF
0,761
0,779
0,821
0,86
Results of the experiments are shown in Table 5 to produce
the best classification model in the dataset displayed in bold.
Shows the proposed model produces increased AUC values
compared to other models.
While in Figure 1 describes the a comparison chart of AUC
values for the four models of the four datasets NASA MDP.
Figure 1. Chart of Comparison AUC values between Previous Model
To know the difference any proposed model, then do a
comparison using the non-parametric statistical calculations
used for the computation of the classifier algorithm. Like,
friedman test.
AUC values model of NB, NB with SMOTE, NB with
SMOTE and IG, and NB with SMOTE and RLF compared
using friedman test described in Table 6.
TABLE 6.
THE P VALUE OF AUC COMPARISON FRIEDMAN TEST
NB
NB with
SMOTE
NB with
SMOTE and
IG
NB with
SMOTE
and RLF
NB (Menzies, 2011)
1
0,046
(Sig)
0,046
(Sig)
0,046
(Sig)
NB with SMOTE
(Riquelme, 2008)
0,046
(Sig)
1
0,317
(No Sig)
0,046
(Sig)
NB with SMOTE and
IG (Putri, 2015)
0,046
(Sig)
0,317
(No Sig)
1
0,046
(Sig)
NB with SMOTE and
RLF (Proposed
Model)
0,046
(Sig)
0,046
(Sig)
0,046
(Sig)
1
As shown in Table 6 shows the proposed model of model
NB with SMOTE and RLF having P value 0.046, then P <α
(0.05). So the NB model with SMOTE and RLF has significant
differences with the pure NB model. The model of his study
also has significant differences with NB, with each P value for
NB with SMOTE is 0.046, while P value NB with SMOTE and
IG is 0.046.
From these results, the SMOTE and RLF model applied to
the Naive Bayesian classification has better calculation
performance than the model that has been proposed with
previous researchers.
V. CONCLUSION
From the results of calculations on research application of
integration of sample method with the selection attribute of
SMOTE and RLF in Naive Bayes classification yields better
AUC value compared to the other model. SMOTE and RLF
model is superior to the two datasets of the four datasets used,
with a value of 78% in the MW1 and 82% datasets on the PC1
dataset.
Whereas when compared with models that have been
proposed by previous researchers, such as Naive Bayesian,
SMOTE on Naive Bayesian, SMOTE and IG on Naive
Bayesian. From the results of research the value of AUC
SMOTE and RLF on Naive Bayesian better performance than
the model in all dataset used in the other research.
This result can be concluded from comparison result using
friedman test, where P value is 0,046, which means P < α
(0,05).
But from these results, the use of sample techniques and
attribute selection algorithms in software defect prediction
research can be done in the next research development,
including:
1. For the selection of attributes in future studies may use
techniques wrapper on attribute selection methods.
2. In further research can use a combination of sample
technique with ensemble algorithm to improve the
performance of the classifier.
3. In further research can use other classifiers, such as
Logistic Regression, Neural Networks and SVM.
ACKNOWLEDGMENT
We should like to express our gratitude to RSW (Romi Satria
Wahono) Intelligent Research Group for warm discussion
about this research. Also for PPPM STMIK Nusa Mandiri
Jakarta and PPPM AMIK BSI Jakarta, which has supported us
to do this research.
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