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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Student Modeling with Clustering: Comparative Analysis of Case Studies in Two Higher Educational Institutions from Different Countries</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Dijana Oreški</string-name>
          <email>dijana.oreski@foi.hr</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Emilija Kisić</string-name>
          <email>emilija.kisic@metropolitan.ac.rs</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Jovana Jović</string-name>
          <email>jovana.jovic@metropolitan.ac.rs</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Miroslava Raspopović Milić</string-name>
          <email>miroslava.raspopovic@metropolitan.ac.rs</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Belgrade Metropolitan University</institution>
          ,
          <addr-line>Tadeuša Košćuška 63, 11000 Belgrade</addr-line>
          ,
          <country country="RS">Serbia</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>University of Zagreb, Faculty of Organization and Informatics</institution>
          ,
          <addr-line>Pavlinska 2, 42000 Varaždin</addr-line>
          ,
          <country country="HR">Croatia</country>
        </aff>
      </contrib-group>
      <fpage>45</fpage>
      <lpage>54</lpage>
      <abstract>
        <p>The focus of this paper is to combine learner data from two different higher education institutions, and specifically, from one course from each institution. Data were collected during one semester in both courses and stored in historical datasets with the aim to identify the most important features from each dataset that contribute to an adequate grouping of students based on their pre-exam activities and gained knowledge during the course's duration. The goal of this paper is to analyze learner data and compare the results with the lesson designs of both courses. The aim is to address future needs for the lesson designs that will be used in a system with lesson content recommendations based on student modeling used for tracking of studentspecific progress.</p>
      </abstract>
      <kwd-group>
        <kwd>1 Student modeling</kwd>
        <kwd>clustering</kwd>
        <kwd>lesson design</kwd>
        <kwd>student progress tracking</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        An important part of intelligent tutoring systems is a student model [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. The student model should
represent the student's current state of knowledge and abstraction of a student's characteristics,
behaviors, learning preferences, and performance [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. These models are essential in learning
environments because they allow personalization of the learning process for each student. Besides the
personalization of the learning content, student models also offer the opportunity for tailored
interventions and focused support when necessary [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ], [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ].
      </p>
      <p>
        Through the analysis of huge amounts of data gathered from students' interactions with learning
platforms, resources, and tests, artificial intelligence (AI) can be used for student modeling [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ]. AI
models use complex algorithms to interpret student's habits, preferences, learning styles, etc. By
analyzing learner data, AI creates student models that student's unique learning preferences, skills, and
knowledge gaps [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ]. Student modeling can be used to capture student characteristics such as
knowledge level, learning style, strengths, shortcomings, and progress trajectory, and in some cases
possibly predict them [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ], [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ]. In order to offer personalized learning experiences it is important to
identify trends in learner data. Using clustering techniques is one approach that can allow to identify
these trends [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]. Learning patterns and behaviors shared by students are the basis for clustering
algorithms, which divide students into discrete categories or clusters. Teachers can use generated
clusters to understand and meet the requirements of a wide range of students [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ]. Moreover, clustering
is an effective technique that identifies groups of students with similar characteristics. This allows for
tailored content recommendations and focused interventions for each student cluster [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ], [14].
      </p>
      <p>In order to effectively develop student models based on learner data, lesson design with planned
learner activities (quizzes, tests, etc.) should be carefully planned and well-structured [15]. A setting
that will allow for easier tracking of student progress includes planning classes with specific goals,
designing learning activities that will engage students, and hence, allow for collection of quality learner
data, and finally, plan adequate assessments [16]. Points in the lesson where learner data that allows
student progress tracking is collected are called lesson breakpoints. Breakpoints can be in the form of
assessment, progress report submission, etc. Even though many different forms of assessments can be
implemented in a lesson, they can all serve a purpose of collecting measurable progress that can show
how engaged, knowledgeable, and successful the students are in the learning at the specific course [17].
In addition, gathering good quality quantitative and qualitative information will allow for building more
precise student models.</p>
      <p>In this work, learner data from two different universities were collected and analyzed. The aim was
to identify patterns in data utilizing clustering algorithms and use the identified clusters to identify
students with different progress levels in their learning. Additionally, the idea was to determine key
features in both datasets and use the conclusions for future lesson designs suitable for more precise
tracking of student progress [18]. By doing this, institutions want to improve the educational
experiences of their students, and at the same time make a significant contribution to the wider
conversation about the potential of artificial intelligence in adaptive e-learning and how to use that
potential through adequate lesson design and process data more easily. This research has the following
goals: (i) to compare and analyze the learner data and used lesson designs from two different courses
to identify characteristics of similar clusters of students based on their activity levels, and (ii) to use
these findings to address needs for the future lesson design needed for learning content recommender
systems based on student modeling. This paper is organized as follows: Section 2 describes the
methodology used for collecting and analyzing data in both involved institutions. Section 2.1 within
section 2 presents lesson designs used in analyzed courses. Section 2.2 within section 2 describes
characteristics and features of both learner datasets. Section 3 presents the results and points out key
findings about the conducted clustering and feature importance analysis. Finally, Section 4 concludes
the paper.</p>
    </sec>
    <sec id="sec-2">
      <title>2. Methodology</title>
      <p>In this paper, two courses from two higher education institutions were analyzed: Belgrade
Metropolitan University, Faculty of Information Technology (FIT, BMU), Serbia, and University of
Zagreb, Faculty of Organization and Informatics (FOI, UNIZG), Croatia. For comparative analysis, two
courses with lesson design shown in Figure 1 were chosen from each institution. Course "Discrete
Structures'' was selected from BMU and the course "Informatics" was selected from FOI. Learner data
that were collected during a semester from both courses were gathered from institutions’ Learning
Management Systems (LMSs). The main goal of this work was to analyze student activities in the
course and group students based on similar features into groups. The aim was to identify which features
give high importance for adequate student grouping. The identification of key features for modeling
student progress is useful for addressing necessary improvements for the future lesson designs that will
be most suitable for extracting useful information about student engagement and progress during the
course duration. The idea is for the future lesson design to include student modeling for tracking student
progress and based on the finding on the level of the progress to recommend student learning content.
In order to do so, in two different institutions, course context and lesson designs from both institutions
were compared, analyzed and intersected with learner data information, in order to make
recommendations for future lesson designs. On its own, student model achieves very little, but with the
use of artificial intelligence techniques, such as clustering and recommendation techniques, it can be
useful for real time tracking of student-specific progress.</p>
      <p>In order to form datasets for both courses different LMSs were used at each institution. On both
courses, different features for forming of datasets were chosen. After datasets were formed, grouping
of students was performed using K-means clustering [19]. After clusterization, feature importance was
performed for gaining the most important features that contribute to the student grouping. After gaining
the results on both institutions, the results were compared, and conclusions were made for better future
lesson design in order to gain reliable student modeling and accurate recommendations for real time
tracking of student-specific progress.</p>
    </sec>
    <sec id="sec-3">
      <title>2.1 Selected lesson designs</title>
      <p>BMU’s course, Discrete structures, was attended by 97 students. This course is offered to first and
second-year students studying in undergraduate academic programs - Information Technology,
Software Engineering and Video Games Development. The particular instance of the course, that is a
part of this analysis, was taken from the course taught during the COVID-19 pandemic and school
closures. Teaching and learning materials were posted on the Learning Activity Management System
(LAMS), while students had weekly lectures with a professor over the Zoom platform. Teaching and
learning materials posted on LAMS were structured as a combination of a series of learning objects
(LOs) and lesson activities. Each lesson consisted of a set of LOs (5-10 LOs). Besides the instructional
materials, lessons contained activities such as not-graded self-assessments after each LO, forum, shared
resources, and mind maps. An example of BMU’s lesson design with LOs and learning activities is
presented in Figure 2. Besides the non-graded lesson activities, students were also given graded
assignments such as homework assignments each week, and approximately every 4-5 weeks, students
were given a test. Both tests and homework assignments were mapped to a specific LO. In other words,
each homework and test evaluated particular knowledge from a LO or set of LOs. Furthermore, tests
were designed with five sections, each section was also mapped to a specific LO or set of LOs. This
was done with an intention, to be able to easier point students towards the recommended material,
should they not pass homework or tests with minimum grade. An example of test organization with
sections is shown in Figure 3. The lesson design, which included mapping teaching materials and
formative assessments for specific sections, facilitated easier tracking of student progress and
identification of areas where students may be struggling within the course.</p>
      <p>FOI’s course Informatics was taught as mandatory in the first semester of the undergraduate study
program Information and Business Systems at the University of Zagreb's Faculty of Organization and
Informatics, and 312 students enrolled in the course. The course was held in a hybrid format, consisting
of lectures and laboratory exercises at the faculty along with course materials and assignments available
through LMS Moodle. Lecture topics were presented to students at the LMS through lesson activities.
Overall, 32 lessons were created on Moodle. Lessons were in multi-resource format, consisting of text,
pictures, videos, and links. Students' knowledge evaluation, among others, was performed by using
selfassessment tests and flash tests.</p>
      <p>There were 12 self-assessment tests throughout the semester. Self-assessment tests were optional,
meaning their results were not part of the final grade. Students could assess it in order to test their
knowledge and as preparation for the midterm exam. Flash tests, on the other hand, were mandatory,
and their results were part of the student's final grade. Questions at self-assessment tests and flash tests
were mapped to the lesson contents. Example of the lesson organization is shown in Figure 4.</p>
      <p>Typically, one course topic was covered with three distinct lesson sections. The lecture entitled Treće
predavanje consisted of lessons: Lekcija 2.1, Lekcija 2.2, and Lekcija 2.3. Self-assessment test entitled
Samporocjena znanja 3, corresponds to a lecture Treće predavanje. Furthermore, the flash test
identified as Blic test 2 assessed gained knowledge from two lectures: Treće predavanje and Četvrto
predavanje, and total of six lessons: Lekcija 2.1, Lekcija 2.2, Lekcija 2.3, Lekcija 2.4, Lekcija 2.5, and
Lekcija 2.6.</p>
      <p>A comparison of key components of lesson designs for BMU and FOI is shown in Figure 1. As we
can see from Figure 1, there are several differences between selected courses in lesson design. Beside
different LMSs and course organizations, one of the key differences is lesson granulation on selected
courses and mapping of student activities on specific parts of the lesson or at the lesson as a whole. At
BMU lessons are represented through LOs and student activities are mapped to specific LOs, while at
FOI there is no mapping to a specific part of the lesson; there is mapping to the lesson as a whole. That
will lead to differences in datasets in the sense that in BMU dataset student activities are mapped on
each LO within the lesson, while at FOI student activities refer to the entire lesson, without mapping to
specific part of the lesson. This means that learner data for BMU in the dataset is represented through
LOs, while for FOI’s learner data through the lessons.</p>
    </sec>
    <sec id="sec-4">
      <title>2.2 Data description</title>
      <p>The dataset obtained from BMU is based on students’ activities during the semester. This dataset
contains four features:
1. ‘Test points’: This variable represents the number of points received on a graded test.
2. ‘Homework points’: This variable represents the number of points received on a homework
assignment.
3. ‘Assessment points’: This variable represents the number of points received on non-graded
selfassessment tests.
4. ‘Time spent on each LO’: This variable was formed as a column with a true or false value, where
true means that student spent some time on specific LO, while false means that student did not
spend any time on specific LO.</p>
      <p>FOI dataset consists of data about students’ LMS Moodle activities, focusing on the lessons. FOI’s
dataset includes following variables:
1. 'Lesson is initiated: This variable represents the number of logs for the lesson, saying how many
times a student started the lesson.
2. 'Lesson is completed': This variable represents the number of logs for each time a student has
viewed the entire lesson.
3. 'Lesson is continued': This variable represents the number of logs for each time when a student
has returned to the already initiated lesson.
4. 'Lesson is restarted': This variable represents the number of logs when the student started the
lesson again.
5. 'Lesson has been reviewed': This variable represents the number of logs in which students
revisited and reopened the lesson again.
6. 'Self-assessment test points': This variable provides information about the number of points that
students achieved in self-assessment tests.
7. 'Flash test points': This variable provides information about the number of points that students
achieved in flash tests.</p>
      <p>The first five variables are related to students’ lessons viewing frequency, whereas the last two
variables, self-assessment test points and flash test points, provide insight into their performance.
Features for both datasets are shown in Table 1.</p>
      <p>It can be seen from Table 1 that datasets have different features, but similar in the sense that selected
course features describe student’s ‘time engagement’ on specific lesson or part of the lesson, and
obtained points on graded or non-graded assessments and tests. Differences among features and
different lessons granularity will lead to diverse conclusions and will give better insight for the future
lesson design.</p>
    </sec>
    <sec id="sec-5">
      <title>3. Results</title>
      <p>In order to group students based on their activities, course progress during the semester, and obtained
knowledge on pre-exam activities, K-means clustering was performed [19]. Different numbers of
clusters were varied for both datasets. For the presentation of the results in this paper, three clusters
were selected, for the purpose of easier comparison between features of two different datasets. Grouping
the students in two clusters was not considered for this paper, as the simplification of two clusters
(engaged and not engaged) would simplify the analysis too much. Clustering identified clearly three
groups of students: very active learners, moderately active learners, and passive learners. Students could
also be grouped into more than three clusters which will lead to more precise grouping and engagement
distinguishing, which will be considered for future work.</p>
      <p>Significance of being able to distinguish between different levels of course progression is important
for the future work, where the goal is to recommend learning content to each student based on their
activity level and obtained knowledge. With the clustering technique, datasets can be labeled and labels
can be used for specific parts of the lesson recommendation or for lesson recommendation as a whole.
Considering identified activity level groups, if a student is in the group of very active learners that
means that based on the student's pre-exam activities the student gained enough knowledge. In the
future student modeling context, if the student satisfied the progress level and obtained knowledge, that
student will not be recommended to revisit a certain part of the lesson. If a student is in the group of
moderately active learners that means that student most likely did not acquire enough knowledge and
is not progressing fully in the course. This student will be recommended to revisit certain parts of the
lesson. If a student is in the group of passive learners, that means that student did not gain enough
knowledge and is lacking in the course activities. This would mean that the future recommender system
will most likely point this student to revisit certain parts or the entire lesson. In this way, each student
could have a recommendation for whether he should relearn a specific part of the lesson, and whether
he has to learn it in detail. This case study was performed on historical datasets, however in real time,
with this type of recommendations in the future, it will be possible to have specific-student progress
tracking during the semester and to intervene with feedback to the student at certain breakpoints for his
better progress.</p>
      <p>As an example of conducted clustering, Figure 5 shows grouping into three clusters for BMU data.
For better visualization, dimension reduction was performed and that is presented with three dimensions
for better visualization. Dimensionality reduction is performed with PCA analysis [20]. In Figure 5 it
can be seen that clusters are well separated, meaning that selected features make significant differences
between student groups.</p>
      <p>For further analysis, feature importance analysis was conducted in order to depict variables with a
higher contribution to the cluster differentiation. Feature importance analysis was undertaken for both
datasets. For the BMU dataset the most important discriminator is the feature ‘Test points.’ This was
expected, because among other features this one was the most informative concerning a student's level
of knowledge and engagement during the semester. Regarding the temporal nature of BMU data, the
course was held during Covid pandemic, so all tests and homework assignments were taken from home,
only the final exam was taken in the classroom. This is something to keep in mind, because of the
objectivity of the received points on the take-at-home tests.</p>
      <p>Within the FOI dataset, the following variables emerged as the most pivotal discriminators:
‘Selfassessment test points’ and 'Lesson is initiated.’ The data analysis conducted on the FOI dataset revealed
a high level of temporal pattern. There is a noticeable trend characterized with increased student activity
at the beginning of semester and after that these activities decreased during the middle of semester.
Another increase in student activity was noticed after the end of the first midterm exam. This could be
attributed to a change in students’ motivation during the semester which was not big at the start of
semester and it increased after their dissatisfaction with grades on the midterm exam. FOI dataset
temporal pattern should be considered for the future lesson design. In the period of decreased activities
and motivation some additional activities should be undertaken to overcome this problem.</p>
      <p>Considering that in both institutions key discriminators were identified, they should be included in
future lesson designs. Considering that test points are showing as a common feature, it should be a
mandatory feature for future student modeling. It may not be obvious how to include “lesson is
initiated” in the lesson design, however, this can be thought of in terms of planning student active
engagement and it is recommended from these results to include this feature or some similar features
in the future data collection.</p>
    </sec>
    <sec id="sec-6">
      <title>4. Conclusions and future work</title>
      <p>This paper analyzed learner data from two different higher educational institutions. One course was
taken from each institution. The goal of this analysis was to identify key features that contribute to
adequate grouping of students in several groups based on their pre-exam activities and gained knowledge
during the course’s duration. K-means clustering was used to separate students into three clusters: very
active learners, moderately active learners, and passive learners. Using feature importance of data,
graded assessments and tests were identified as the key discriminators. Conclusions after comparative
analysis gave insight into more appropriate lesson design planning for the future courses where student
modeling based recommendations are planned. In other words, formative testing should be planned in
the course as soon as possible, in order to be able to track student progress as early as possible. The
temporal nature of the BMU’s data should be taken into consideration. BMU’s course was held during
the pandemic, and students completed their assessments and tests from home. On the other hand, the
temporal pattern in the FOI dataset revealed fluctuations in student activity and motivation throughout
the semester. This suggests that needed interventions and course activities should be aware of these
temporal instances and should keep engaging and motivating students more as the semester progresses.</p>
      <p>In the lesson design of each institution different granularity levels of teaching materials were used.
BMU used learning objects as their sections of the lessons, and mapped their assessments and
assignments to particular LOs. FOI used lesson formats without finer mapping to the lesson sections.
After the clustering, it was evident that different granularity produced different distribution of students
among clusters and we can conclude that finer granularity of teaching content in future will lead to more
precise recommendations of learning content. Having in mind that graded assessments and tests showed
the highest significance in feature importance, this pointed towards the need to carefully plan their
placement in the lesson design. It is recommended that graded assignments are placed as early as
possible, where they will be used to assess certain knowledge or learning outcomes. Assessments should
also be designed with a level of granularity that allows for the pinpointing parts of the lesson that the
student has not fully adopted. Future lesson design should additionally consider incorporating elements
that will provide a greater number of features for machine learning algorithms. This includes
considering elements such as the frequency of student access to each section, completion status, test
points, and homework points. This comprehensive approach will enable a more diverse feature
collection and successful data integration between institutions with the final goal of real time
specificstudent progress tracking and learning content recommendations.</p>
    </sec>
    <sec id="sec-7">
      <title>Acknowledgements</title>
      <p>The paper is co-supported by the Ministry of Science, Technological Development and Innovations
of the Republic of Serbia ref. no. 451-03-47/2023-01/200029.
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