2.3 PART
PART, short for Projective Adaptive Resonance The-
ory, was projected by Frank and Witten (1998). This
algorithm takes advantage of the construction of the
tree based on C4.5 algorithm and from separate to
conquer rule learning strategy of RIPPER.
According to Frank and Witten (1998), this algo-
rithm has three main steps, they are:
1. Induce a rule from a partial tree;
2. remove all instances that are not covered by the
rule;
3. induce new rules from the remaining instances.
Frank and Witten (1998) emphasize that PART,
once that combines two paradigms, C4.5 and RIP-
PER, produces good results without global optimiza-
tion.
3 METHODS
The dataset used in this article were extracted from
Learning Management System Moodle - Modu-
lar Object-Oriented Dynamic Learning Environment.
LMS recorded the actions of 229 students that en-
rolled an online course of Algorithm during the sec-
ond semester of 2016. Initially the dataset had 75,948
instances and 42 features, each feature representing
possibles actions performed by one of the 229 stu-
dents and each instance representing an action taken
by one student. Therefore an average of 331.65
(75,948/229) actions per student.
3.1 Pre-processing
After being extracted from LMS, the data was pre-
processed. During this stage the data was transform
such that each instance represents a student and each
attribute a kind of action performed by the students.
After the transformation, the dataset was with 229 in-
stances and 42 attributes.
Once that not all students perform all actions,
there was many missing data in the dataset. For exam-
ple, only 8 students performed ”chat talk” action, only
1 performed ”course report log”, and so on. Therefore
it was discarded 23 features during the pre-processing
stage due to missing data.
It was also added a new dichotomy’s feature, Sta-
tus. This is a variable with the domain 1, student ap-
proved, or 0, student failure. Status were computed
according to the grade of the student. Students with fi-
nal grade greater than or equal to 70, it was attributed
1 to Status, approved, otherwise it was attributed 0.
The final dataset is compound of 20 features, be-
ing one target, Status, and 19 predictive variables.
Those explanatories variables describe actions per-
formed by students such as visualizing tasks, submit-
ting assignments, participating in chats and other ac-
tions that are part of the routine of the students. Table
1 describes each variable of the data set, access mean
and standard deviation for each action performed by
the 229 students at Moodle during the course.
The dataset analyzed was with 229 instance repre-
senting the students in which 135 were approved and
94 failure, this means that 41% failure in the course.
3.2 Rule Induction
After being preprocessed, three algorithms were ap-
plied to the dataset: OneR, RIPPER and PART. It was
used R language and IDE StudioR version 1.0.136.
OneR is based on the OneR library and for RIPPER
and PART it was used RWeka library (Hornik et al.,
2008)
All 20 attributes were discretized through the
function optbin of the library OneR of the R Lan-
guage. This function makes discretization of numeric
data considering the target variable. Besides that, it is
used logit regression to define the number of factors
of the discretization.
The model used to train all algorithms was
the simplest cross validation method, hold-out
(Kuncheva, 2014). The dataset was divided in train,
80% of the data set (183 instances), and test, 20% (46
instances).
4 EXPERIMENTS AND RESULTS
The first algorithm applied into the educational
dataset were OneR. Table 2 presents five attributes
with the lowest error rate.
Most of the features presented in Table 2 are re-
lated to an assignment as described in table 1, only
attribute course.view is not directly linked to an evalu-
ation activity. Considering the feature assign.submit,
attribute with minor error rate, OneR identified two
rules, they are:
1. i f assign.submit = (−0.014,5] then Status = 0
2. i f assign.submit = (5,14] then Status = 1
According to the contingency table, Table 3, 68
instances are covered by rule number one and 115 by
rule number two, implying in 37.3% and 67.2% cov-
erage. Rule number one has an accuracy of 88.2%
and number two, 85.2%. Considering both rules the
accuracy is 86.34%, 158/183, as shown in Table 2.
Rule Induction Algorithms Applied in Educational Data Set
693