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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Studio: Ontology-Based Educational Self-Assessment</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Christian Weber</string-name>
          <email>cweber@corvinno.com</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Réka Vas</string-name>
          <email>reka.vas@uni-corvinus.hu</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Corvinno Technology, Transfer Center</institution>
          ,
          <addr-line>Budapest</addr-line>
          ,
          <country country="HU">Hungary</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Corvinus University, of Budapest</institution>
          ,
          <addr-line>Budapest</addr-line>
          ,
          <country country="HU">Hungary</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>Students, through all stages of education, grasp new knowledge in the context of knowledge memorized all through their previous education. To self-predict personal proficiency in education, selfassessment acts as an important learning feedback. The in-house developed Studio suit for educational self-assessment enables to model the educational domain as an ontology-based knowledge structure, connecting assessment questions and learning material to each element in the ontology. Self-assessment tests are then created by utilizing a sub-ontology, which frames a tailored testing environment fitting to the targeted educational field. In this paper we give an overview of how the educational data is modeled as a domain ontology and present the concepts of different relations used in the Studio system. We will deduct how the presented self-assessment makes use of the knowledge structure for online testing and how it adapts the test to the performance of the student. Further we highlight where potentials are for the next stages of development.</p>
      </abstract>
      <kwd-group>
        <kwd>Education</kwd>
        <kwd>adaptive test</kwd>
        <kwd>self-assessment</kwd>
        <kwd>educational ontology</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. INTRODUCTION</title>
      <p>
        Students exploring new fields of education are always confronted
with questions regarding their individual progress: how much do
they know after iterations of learning, in which directions should
they progress to fill the field most effectively, how to grasp the
outline and details of the field and how much of their time
should they invest in learning? Especially in higher education,
where learning becomes a self-moderated, personalized process,
students are in need of continuous self-assessment to capture
their current state of proficiency. At the same time, the
unframed, informal self-prediction of students regarding their
personal skills is often substantive and systematically flawed [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ].
Here a systematic and objective solution for self-assessment is
substantial to prevent a wrong or biased self-evaluation and to
support the self-prediction of the personal proficiency.
Following Jonassen, knowledge in education could be split into
nine types across three categories to capture the human’s
cognitive behavior. In his discussion, eight out of nine knowledge
types underline that knowledge in the scope of learning is
interrelated and strongly associated with previous experiences
[
        <xref ref-type="bibr" rid="ref2">2</xref>
        ]. As such, a supporting solution for self-assessment should
grasp and formalize the knowledge to assess in the context of
related knowledge.
      </p>
      <p>The Studio suit for educational self-assessment, presented in this
paper, provides here a software solution for testing the personal
proficiency in the context of related knowledge. It enables to
model areas of education as a substantial source for assessment
and narrows the gap between a potentially flawed self-prediction
and the real proficiency, by offering an objective and adaptive
online knowledge-test. To follow the natural learning process
and enable an easy extension, the software embeds the assessed
knowledge into a network of contextual knowledge, which
enables to adapt the assessment to the responses of the students.
This paper will give an overview of the Studio educational
domain ontology and the aspects of the system supporting
personalized self-assessment. Further it will highlight potentials
for data mining on the gathered educational data with an outlook
on the next stages of evaluation.</p>
    </sec>
    <sec id="sec-2">
      <title>2. THE STUDIO APPROACH FOR SELF</title>
    </sec>
    <sec id="sec-3">
      <title>ASSESSMENT</title>
      <p>The basic concept of Studio is to model the focused education as
an interrelated knowledge structure, which divides the education
into sub-areas and knowledge items to know. The managed
structure formalizes the relation between knowledge areas as a
learning context and models the requirements to master specific
parts of the education. This structure is used to create and
support knowledge tests for students. Through this combination
of assessment and knowledge structure, the student gains the
freedom to explore not only single knowledge items but the
education in the context of related knowledge areas, while the
embedded requirements are used to map the modeled knowledge
against the expected educational outcome.</p>
      <p>The assessment-system is designed to be accompanied by phases
of learning within the system, where the student gets access to
learning material, based on and supported by the test feedback.
This combined approach offers a unique self-assessment to the
students, where the backing knowledge context is used to adapt
the assessment in dependency of the test performance of the
student.</p>
      <p>Before any regular examination students may use Studio to
assess their knowledge on their own. It is the tutor’s
responsibility to set the course of self-assessment test in Studio
system by selecting knowledge areas and sub-knowledge areas
which are relevant for the target education from the domain
ontology. Then the frame will be automatically completed with
elements from the ontology which detail the selected knowledge
areas and are modeled as required for this part of the education.
As the system stores assessment questions for each knowledge
element, Studio will then automatically prepare an assessment
test, based on the defined selection and the domain ontology. The
resulting knowledge-test is then accessible as a self-assessment
test for the student, who explores the backed knowledge
structure, which pictures the expected learning outcome, in
cycles of testing, reflection and learning. The process of test
definition and assessment is shown in Figure 1, while the result
preparation for reflection and learning is discussed in section 2.5.</p>
    </sec>
    <sec id="sec-4">
      <title>2.1 The Educational Domain Ontology</title>
      <p>
        The Studio system is based on a predesigned educational
ontology, explained in detail by Vas in [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Domain ontology is a
frequently used term in the field of semantic technologies and
underlines the storage and conceptualization of domain
knowledge and is often used in a number of projects and
solutions [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ][
        <xref ref-type="bibr" rid="ref5">5</xref>
        ][
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] and could address a variety of domains with
different characteristics in their creation, structure and
granularity, depending on the aim and the modeling person [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ]. A
specialization in terms of the field is the educational domain
ontology which is a domain ontology adapted to the area and
concepts of education. They could target to model different
aspects of education as the curriculum or aspects relevant for the
task of learning and course creation [
        <xref ref-type="bibr" rid="ref8">8</xref>
        ][
        <xref ref-type="bibr" rid="ref9">9</xref>
        ][
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] or describe the
design, use and retrieval of learning materials till creating
courses [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ], as well as directly the learner within the education
[
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
      </p>
      <p>Within the area of educational ontologies, domain ontologies
tend to model too specific details of the education, in an attempt
to model the specific field as complete as possible. This enables
a comprehensive view on the field but it comes at the cost of
generality, with the potential to be inflexible to handle changes.
Other concepts model the education across different ontologies,
matching concepts like the learner, the education and the course
description, introducing a broad horizon but with additional
overhead to combine modelled insights and reason on new
instances.</p>
      <p>
        The appeal of the Studio educational ontology is the size and
focus of the main classes and their relationships between each
other. The knowledge to learn is the main connecting concept in
the core of education. It enables a great flexibility to be
resourceful for different education related questions. An example
is here the business process management extension PROKEX,
which maps process requirements against knowledge areas to
create assessment test, reflecting the requirements of attached
processes [
        <xref ref-type="bibr" rid="ref13">13</xref>
        ].
      </p>
      <p>
        An important factor in learning is the distance between the
expectation of the tutor and the learning performance of the
student. Here a short cycle of repeated assessment and learning
is a major factor for a better personal learning performance [
        <xref ref-type="bibr" rid="ref14">14</xref>
        ].
This aspect directly benefits from the focused concentration on
knowledge-areas as the main exchange concept between students
and tutors. As even further the close connections between
learners and educators via direct tutoring is one major enabler for
computer aided systems [
        <xref ref-type="bibr" rid="ref15">15</xref>
        ], each step towards a more direct
interaction through focused concepts is an additional supporter.
The class structure fuses the idea of interrelated knowledge with
a model of the basic types of educational concepts, involved in
situations of individual learning. Figure 2 visualizes the class
concepts as knowledge elements, together with the relation types,
used to model the dependencies between different aspects of
knowledge and learning within the educational ontology.
The Knowledge Area is the super-class and core-concept of the
ontology. The ontology defines two qualities of main relations
between knowledge areas: Knowledge areas could be a
subknowledge area of other knowledge areas with the
“has_subknowledge_area” relation or be required for another knowledge
area with the “requires_knowledge_of” relation. A knowledge
area may have multiple connected knowledge areas, linked as a
requirement or sub-area. The “requires_knowledge_of” relation
defines that a node is required to complete the knowledge of a
parent knowledge area. This strict concept models a requirement
dependency between fields of knowledge in education and yields
the potential to assess perquisites of learning, analog to the basic
idea of perquisites within knowledge spaces, developed by
Falmagne [
        <xref ref-type="bibr" rid="ref16">16</xref>
        ].
      </p>
      <p>Education is a structured process which splits the knowledge to
learn into different sub-aspects of learning. Knowledge areas in
the ontology are extended by an additional sub-layer of
knowledge elements in order to effectively support educational</p>
      <p>Theorems express in a condensed and structured way the
fundamental insights within knowledge areas. They fuse and
explain the basic concepts of the depicted knowledge and set
them in relation to the environment of learning with examples.
Multiple theorems could be “part_of” a knowledge area. Each
theorem may define multiple Basic Concepts as a “premise” or
“conclusion”, to structure how the parts of the knowledge area
are related. Examples enhance this parts as a strong anchor for
self-assessment questions and “refer_to” the theorems and basic
concepts as a “part_of” one or more knowledge areas.</p>
    </sec>
    <sec id="sec-5">
      <title>2.2 The Testbank</title>
      <p>In order to connect the task of self-assessment with the model of
the educational domain, the system integrates a repository of
assessment questions. Each question addresses one element of
the overall knowledge and is directly associated with one
knowledge area or knowledge element instance within the
ontology. The domain ontology provides here the structure for the
online self-assessment while the repository of questions
supplements the areas as a test bank. The target of the
selfassessment is to continuously improve the personal knowledge
within the assessed educational areas, by providing feedback on
the performance after each phase of testing. To do so, the Studio
system includes Learning Material connected to the test bank and
the knowledge areas, analog to the test questions. The learning
material is organized into sections as a structured text with
mixed media, as pictures and videos, and is based on a
wikiengine to maintain the content, including external links.
and testing requirements. Figure 2 visualizes the sub-elements
and their relations. By splitting the assessed knowledge into
subconcepts, the coherence and correlation of self-assessment
questions could be expressed more efficiently and with the
potential of a more detailed educational feedback.</p>
      <p>Has
subknowledge area</p>
      <p>Knowledge Area</p>
      <p>Requires
knowledge of
Part of</p>
      <p>Part of</p>
      <p>Part of
Basic Concept
Example</p>
    </sec>
    <sec id="sec-6">
      <title>2.3 Creating and Maintaining Tests</title>
      <p>
        The creation and continues maintenance of the domain ontology
is a task of ontology engineering. The ontology engineer (the
ontologist), creates, uses and evaluates the ontology [
        <xref ref-type="bibr" rid="ref17">17</xref>
        ], with a
strong focus on maintaining the structure and content. Within
Studio, this process is guided and supported by a specialized
administration workflow and splits in three consecutive task
areas, in line with decreasing access rights:
      </p>
      <sec id="sec-6-1">
        <title>Ontology engineering (instance level): The creation</title>
        <p>and linking of instances of the existing knowledge-area
classes into the overall domain ontology.</p>
        <sec id="sec-6-1-1">
          <title>Test definition: Knowledge areas, which are relevant</title>
          <p>to a target self-assessment test, are selected and
grouped into specialized containers called Concept
Groups (CG). These concept groups are organized into
a tree of groups, in line with the target of the
assessment. The final tree in this regards captures a
sub-ontology. Concept groups are internally organized
based on the overall ontology and include all relations
between knowledge elements, as defined within the
domain ontology.</p>
          <p>Question and learning material creation: Questions
and learning materials alike are directly connected to
single knowledge areas within the designed test frame
and get imported, if already existing, from the domain
ontology. More questions and learning materials are
defined now, in line with the additional need of the
targeted education and are available for future tests.</p>
          <p>The pre-developed structure of classes and relations is fixed as
the central and integral design of the system. A view of the
system interface for administration is provided in Figure 3. The
left area shows the visualization of the current ontology section
in revision and the right area shows the question overview with
editing options. Tabs give access to additional editing views,
including the learning material management and interfaces to
modify relations between nodes and node descriptions.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-7">
      <title>2.4 Adaptive Self-Assessment</title>
      <p>To prepare an online self-assessment test, the system has to load
the relevant educational areas from the domain ontology and
extract the questions and relations of the filtered knowledge
areas.</p>
      <p>The internal test algorithm makes use of two assumptions:
Knowledge-area ordering: As the main knowledge
areas are connected through “requires_knowledge_of”
and “part_of” relations, every path, starting with the
start-element, will develop on average from general
concepts to detailed concepts - given that the concept
groups in the test definition are also selected and
ordered to lead from general to more detailed groups.</p>
      <sec id="sec-7-1">
        <title>Knowledge evaluation dependency: If a person,</title>
        <p>taking the test, fails on general concepts he or she will
potentially also fail on more detailed concepts. Further,
if a high number of detailed concepts are failed, the
parent knowledge isn’t sufficiently covered and will be
derived as failed, too.
The filtering is done based on the selection of a tutor, acting as
an expert for the target educational area. The tutor chooses
related areas, which are then created as a Test Definition,
containing Concept Groups, as described in section 2.3. The
system then uses the test definition as a filtering list to extract
knowledge areas. After the extraction, the structure is cached as
a directed graph, while the top element of the initial concept
group is set as a start element. Beginning with the start-element,
the test will move then through the graph, while administering
the questions connected to knowledge areas and knowledge
elements.</p>
        <sec id="sec-7-1-1">
          <title>The loading of knowledge-elements follows three steps: 1. 2. 3.</title>
          <p>Each type of relation between two knowledge-elements
implements a direction for the connection. Assuming
the system loads all relations, starting with the
startelement and ending on a knowledge-element, this
creates a two level structure where the start-node is a
parent-element and all related, loaded elements are
child-elements, as seen below in Figure 4.</p>
        </sec>
        <sec id="sec-7-1-2">
          <title>The loading algorithm then selects one child-element</title>
          <p>and assumes it as a start-element and repeat the
loading process of knowledge-elements.</p>
        </sec>
        <sec id="sec-7-1-3">
          <title>When no knowledge-elements for a parent-element could be loaded, the sub-process stops. When all subprocesses have stopped, the knowledge structure is fully covered.</title>
          <p>The test algorithm will now activate the child knowledge areas of
the start element and select the first knowledge area to the left
and draw a random question from the selected knowledge area. If
the learner fails the question, the algorithm will mark the
element as failed and selects the next knowledge area from the
same level. If the learner’s answer is correct, the system will
activate the child elements of the current node and draw a
random question from the first left child.</p>
          <p>Based on the tree shaped knowledge structure, the assessment
now follows these steps to run the self-assessment, supported by
the extracted knowledge structure:
1.
2.</p>
        </sec>
        <sec id="sec-7-1-4">
          <title>Starting from the start-element, the test algorithm will</title>
          <p>activate the child knowledge-areas of the start element.</p>
        </sec>
        <sec id="sec-7-1-5">
          <title>The algorithm now selects the first child-knowledge area and draws a random question out of the pool of available questions for this specific knowledge-element from the test bank.</title>
        </sec>
        <sec id="sec-7-1-6">
          <title>If the learner fails the question, the algorithm will</title>
          <p>mark the element as failed and select the next
knowledge area from the same level. If the learner’s
answer is correct, the system will activate the child
elements of the current node and trigger the process for
each child-element.</p>
          <p>An example question is shown below in Figure 5. Further
following the testing algorithm, the system dives down within the
domain ontology and triggers questions depending on the
learner’s answers and the extracted model of the relevant
education. In this regards the Studio system adapts the test on the
fly to the performance of the learner. Correlating to the idea of
adaptation, the learner will later gain access to learning material
for each mastered knowledge area. As the learner continues to
use the self assessment to evaluate the personal knowledge, he or
she will thus explore different areas of the target education,
following their individual pace of learning.</p>
        </sec>
      </sec>
    </sec>
    <sec id="sec-8">
      <title>2.5 Test Feedback and Result Visualization</title>
      <p>An important aspect of the system is the test feedback and
evaluation interface. The educational feedback is one of the main
enabler for the student to grasp the current state and extend of
the personal education. The domain ontology models the
structure and the dependencies of the educational domain, and
the grouped test definition extracts the relevant knowledge for
the target area or education. As such, the visualization of the
ontology structure extracted for the test, together with the
indication of correct and incorrect answers, represents a map of
the knowledge of the learner.</p>
      <p>
        Throughout each view onto the ontology, the system uses the
same basic visualization, making use of the Sencha Ext JS
JavaScript framework [
        <xref ref-type="bibr" rid="ref18">18</xref>
        ]. The visualization itself is a custom
build, similar to the Ext JS graph function “Radar” and based on
the idea of Ka-Ping, Fisher, Dhamija and Hearst [
        <xref ref-type="bibr" rid="ref19">19</xref>
        ]. All views
are able to zoom in and out of the graph, move the current
excerpt and offer a color code legend, explaining the meaning of
the colored nodes. In comparison with state of the art, the
interface offers no special grouping or additional visualization
features like coding information into the size of nodes. Each
interface offers an additional textual tree view to explore the
knowledge-elements or concept groups in a hierarchical listing.
This simple, straightforward approach for visualization correlates
with the goal of a direct and easy to grasp feedback through
interfaces which have a flat learning curve and enable to catch
the functionality in a small amount of time.
      </p>
      <p>While this simple visualization is sufficient for the reasonable
amount of knowledge-elments within the result view, this alone
is not suitable for the domain ontology administration interface,
as seen in Figure 3. Here Studio realizes methodologies to filter
and transform the data to visualize. To do so it makes use of two
supporting mechanisms:</p>
      <sec id="sec-8-1">
        <title>The maximum-level-selector defines the maximum</title>
        <p>level the system extracts from the domain ontology for
full screen visualization.</p>
        <p>
          In combination with the maximum level, the ontologist
could select single elements within the domain
ontology. This triggers an on-demand re-extraction of
the visualized data, setting the selected
knowledgeelement as the centre element. The system then loads
the connected nodes, based on their relations into the
orientation circles till the maximum defined level is
reached. More details about the transformation are in
[
          <xref ref-type="bibr" rid="ref19">19</xref>
          ].
Together, this selection and transformation mechanism enables
the fluent navigation within the complete domain ontology
structure, while re-using the same visualization interface.
Figure 6 shows the main view of the result interface. The left
area shows the sub-ontology extracted for the test, while the
colored nodes represent the answers to the administered
questions. A red node visualizes wrong answers, while orange
nodes are rejected nodes with correct answers but with an
insufficient number of correctly answered child nodes,
indicating a lack of the underlying knowledge. Green nodes
represent accepted nodes with correct answers and a sufficient
amount of correctly answered questions for child nodes. Grey
nodes are not administered nodes, which were not yet reached
by the learner, as higher order nodes had no adequate
acceptance.
        </p>
        <p>Even though the target of the system is not a strict evaluation in
number, the evaluation of the percentage of solved and
accepted knowledge elements helps the learner to track the
personal progress and could additionally be saved as a report
for further consultation. Besides providing an overview of the
self-assessment result, the result interface gives access to the
integrated learning material. For every passed node, the learner
can now open the correlated material and intensify the
knowledge for successful tested areas.</p>
        <p>Retaking the test in cycles of testing and learning, while
adapting the educational interaction, is the central concept of
the Studio approach for self-assessment. As a consequence the
system will not disclose the right answers to questions or
learning material for not yet administered knowledge areas, to
promote an individual reflection on the educational content
outside of a flat memorization of content.</p>
      </sec>
    </sec>
    <sec id="sec-9">
      <title>3. SYSTEM EVALUATION</title>
      <p>
        The system has been used, extended and evaluated in a number
of European and nationally funded research projects, including
applications in business process management and
innovationtransfer [
        <xref ref-type="bibr" rid="ref20">20</xref>
        ], medical education [
        <xref ref-type="bibr" rid="ref21">21</xref>
        ] and job market
competency matching [
        <xref ref-type="bibr" rid="ref22">22</xref>
        ].
      </p>
      <p>
        Currently the system is being evaluated based on a running
study with 200 university students in the field of business
informatics. The study will conclude on two current research
streams which are improving the systems testing and analysis
capability. The first direction looks into potentials for the
integration of learning styles into adaptive learning systems to
offer valuable advice and instructions to teachers and students
[
        <xref ref-type="bibr" rid="ref23">23</xref>
        ]. Within the second direction the question is challenged on
how to adapt the presented self-assessment further towards the
performance of the students, based on extracting assessment
paths from the knowledge structure [
        <xref ref-type="bibr" rid="ref24">24</xref>
        ].
      </p>
      <p>For each running test, Studio collects basic quantitative data
about the number of assigned questions, how often tests are
taken and how many students open which test and when. This
is completed by qualitative measures, collecting which
questions and knowledge elements the students passed or
failed. To conclude further on the mechanisms and impacts of
Studio within the current study, a new logging system was
developed, collecting the interaction with the system and
detailed information about the feedback as detailed events.
Each event stores information about the system in 7
dimensions, as described in Table 1 below:</p>
      <p>All events are stored in order of their occurrence, so if no
explicit end event is defined, the next event for the same
session and user is acting as the implicit end date. Extending
the existing storage of information within Studio, the new
logging system stores the additional events, as shown in Table
2 below:</p>
      <p>To store the events, the system implements an additional
logging database, splitting the concepts of the logging to a
starschema for efficient extraction, transformation and loading. The
logging system is modular and easy to extend with new
concepts and easy to attach to potential event positions within
the Studio runtime. Together with the existing logging of the
assessment evaluation feedback, this new extension tracks the
exploration of the sub-ontology within the assessment and
enriches the feedback data with context information of the
students behavior on the system.</p>
    </sec>
    <sec id="sec-10">
      <title>4. NEXT STEPS</title>
      <p>
        The domain ontology offers a functional and semantically rich
core for supporting learning and education. Yet not all the
semantic potentials are fully leveraged to support and test the
learner’s progress. The “requires_knowledge_of”
relationrequirement is a potential start-concept to model sub-areas as
groups which together compose the dependency. This could act
as an additional input for the assessment, where the system
derives more complex decision how to further explore the
related parts of the structure [
        <xref ref-type="bibr" rid="ref25">25</xref>
        ]. This could also be visualized,
enabling the learner to grasp the personal knowledge as a
visible group of concepts.
      </p>
      <p>Besides giving colors to the different types of relations, the
visualizing of edges between knowledge areas is yet unfiltered,
offering no further support for navigation. A next stage of
implementation could be the introduction of a visual ordering
and grouping of knowledge areas and relations. Underlying
relations of sub-nodes could be interpreted visually through the
thickness of relations between nodes, easing the perception of
complex parts of the domain ontology, especially within
administration and maintenance tasks.</p>
      <p>
        The feedback of the current evaluation study of Studio will
provide additional insights into the usage of the system by the
students. Based on this new data it is possible to mine profiles
over time on the knowledge structure. One major application is
here the creation of behavior profiles, as proposed in [
        <xref ref-type="bibr" rid="ref23">23</xref>
        ].
      </p>
    </sec>
  </body>
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