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<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>DiLibS Platform for a Virtual Education Space</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>A. Stoyanova-Doycheva</string-name>
          <email>astoyanova@uni-plovdiv.net</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>E. Doychev</string-name>
          <email>e.doychev@uni-plovdiv.net</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>V. Ivanova</string-name>
          <email>v.ivanova@uni-plovdiv.net</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>V. Valkanova</string-name>
          <email>veselina_viva@abv.bg</email>
          <xref ref-type="aff" rid="aff2">2</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>The Distributed eLearning Centre (DeLC)</string-name>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>S. Stoyanov</string-name>
          <email>astoyanova@uni-plovdiv.net</email>
          <email>stani@uni-plovdiv.net</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Faculty of Mathematics and Informatics, University of Plovdiv</institution>
          ,
          <country country="BG">Bulgaria</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Faculty of Mathematics and</institution>
          ,
          <addr-line>Informatics</addr-line>
          ,
          <institution>University of Plovdiv</institution>
          ,
          <country country="BG">Bulgaria</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Secondary School “Sofronij Vrachanski”</institution>
          ,
          <addr-line>Plovdiv</addr-line>
          ,
          <country country="BG">Bulgaria</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>developed at the Faculty of Mathematics and, Informatics aims at the delivery of electronic, education services and teaching content, personalized and customized for each, individual user. In this paper are presented, some general characteristics and the, architecture of VES (Virtual Education, Space), a successor to DeLC. In addition, the, core of a space called DiLibS platform is</institution>
          ,
          <addr-line>considered.</addr-line>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2015</year>
      </pub-date>
      <fpage>10</fpage>
      <lpage>18</lpage>
      <abstract>
        <p />
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>1. Introduction</title>
      <p>
        In recent years the interest towards electronic
education has been growing stronger. Higher
education is facing a renaissance in terms of its
approaches to teaching and learning and the use of
physical and virtual spaces. Universities are no longer
defined by the physical boundaries of their traditional
campus but are closely connected to virtual
environments [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. It is expected that a virtual
education space, integrating physical and virtual
worlds and supporting various learning approaches,
styles and forms will contribute to the achievement of
any-time, any-where and any-how education. One of
the first projects, called Virtual Education Space
(VES), belongs to the Massachusetts University. It is
an educational intranet for educators and students
which provides a secure and personalized portal with
a set of online tools and resources designed to support
preK-12 standards-based education [2]. The primary
objective of the system is to improve student learning
by collaboratively designing and implementing an
educational information management system that
provides for the effective use and exchange of
information among educators and school systems. In
accordance with [3] learning spaces are: physical,
blended or virtual learning environments that enhance
as opposed to constrain learning; physical, blended or
virtual ‘areas’ that motivate a user to participate for
learning benefits; spaces where both teachers and
students optimize the perceived and actual
affordances of the space; spaces that promote
authentic learning interactions.
      </p>
      <p>
        As a result, many universities have developed and
implemented their own systems for electronic and
long-distance education. In line with this trend, a
Distributed eLearning Centre (DeLC) project was
implemented at the Faculty of Mathematics and
Informatics at the University of Plovdiv, Bulgaria,
aiming at the development of an infrastructure for
context-aware delivery of electronic education
services and teaching content, personalized and
customized for each individual user [
        <xref ref-type="bibr" rid="ref3 ref4">4,5</xref>
        ]. DeLC is a
reference architecture, supporting a reactive,
proactive and personalized provision of education
services and electronic content. The DeLC
architecture is modeled as a network which consists
of separate nodes, called eLearning Nodes. Nodes
model real units (laboratories, departments, faculties,
colleges, and universities), which offer a complete or
partial educational cycle. Each eLearning Node is an
autonomous host of a set of electronic services. The
configuration of the network edges is such as to
enable the access, incorporation, use and integration
of electronic services located on the different
eLearning Nodes. The eLearning Nodes can be
isolated or integrated in more complex virtual
services offered by it. The reorganization does not
disturb the function of other nodes (as nodes are
autonomous self-sufficient educational units
providing one or more integral educational services).
Wired and wireless access to the eLearning services
and teaching content has been implemented in DeLC.
The current DeLC infrastructure consists of two
separate education clusters [
        <xref ref-type="bibr" rid="ref5">6</xref>
        ]. The first one, known
as MyDeLC, delivers educational services and
teaching content through an educational portal. The
second one provides mobile access to services and
content over an extended local network called
      </p>
      <sec id="sec-1-1">
        <title>Education Portal</title>
        <p>structures, called clusters. Remote eService activation
and integration is possible only within a cluster. In the
network model we can easily create new clusters,
reorganize or remove existing clusters (the
reorganization is done on a virtual level, it does not
affect the real organization). For example, the
reorganization of an existing cluster can be made not
by removing a node but by denying access to the</p>
      </sec>
      <sec id="sec-1-2">
        <title>InfoStations.</title>
        <p>The Virtual Education Space (VES) is developing
as a successor to DeLC and it accounts for two
important tendencies in the development of the
Internet and the Web. The first tendency is the
transformation of the Internet into Internet of Things
[7] stimulating the origin of cyber-physical social
systems which will lead to essential technological,
Operatives</p>
      </sec>
      <sec id="sec-1-3">
        <title>Guards</title>
        <p>DiLib</p>
      </sec>
      <sec id="sec-1-4">
        <title>Admin 11</title>
      </sec>
      <sec id="sec-1-5">
        <title>Personal Assistants</title>
        <p>
          economical and sociological consequences in the
following years. This type of systems can introduce
new approaches and scenarios for solving complex
problems in the field of electronic education. The
second tendency is the rise and growth of the
Semantic Web [
          <xref ref-type="bibr" rid="ref7 ref8">8, 9</xref>
          ]. Some ideas for the usage of the
semantic web in electronic education are presented in
[
          <xref ref-type="bibr" rid="ref9">10</xref>
          ]. At the current moment using the capabilities of
the Semantic Web in electronic education is the
subject of strong scientific interest.
        </p>
        <p>In thе first section, a general overview of the VES
architecture is presented. The second section
examines the core of the virtual education space,
known as the DiLibS platform. Two use cases are
discussed in the third section.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>2. VES Architecture</title>
      <p>
        Our goal is to develop the virtual space with the
following features:
• Intelligent – it can continuously monitor
what is happening in it, can communicate
with its inhabitants and neighbourhoods, can
make related inferences and decisions and
act on these decisions [
        <xref ref-type="bibr" rid="ref10 ref11">11, 12</xref>
        ];
• Context-aware – the ability to find, identify
and interpret the changes (events) in the
space [
        <xref ref-type="bibr" rid="ref12">13</xref>
        ] and, depending on their nature, to
undertake compensating actions. The main
compensating actions (attributes for
contextdependency) are personalization and
adaptation;
• Scenario-oriented – from a user’s point of
view, the space is a set of separate e-learning
services and educational scenarios provided
for use through the education portal DeLC or
personal assistants. Scenarios are
implemented by corresponding workflows
rendering an account of the environment’s
state. Thus it is possible to take into account
various temporal characteristics (duration,
repetition, frequency, start, or end) of the
educational process or events (planned or
accidental) which can impede or alter the
running of the current educational scenario.
To deal with emergencies (such as an
earthquake, flood, or fire) there are defined
emergency scenarios which are executed
with the highest priority;
• Controlled infrastructure – access to the
space’s information resources is only
possible through the so-called "entry points."
      </p>
      <p>The personal assistants operate as typical
entry points while the education portal of
DeLC is a specialized entry point; a user has
to be in possession of a personal assistant or
to use the portal to be able to work in the
space.</p>
      <p>The VES architecture contains different types of
components. Assistants play an important role in the
space. Three types of assistants are supported in the
space (Figure 1.). The personal assistants have to
perform two main functions providing the needed
“entry points” of the space. Firstly, they operate as an
interface between their owners and the space and, if
necessary, carry out activities related to
personalization and adaptation. Secondly, they
interact with other assistants in the space in order to
start and control the execution of the generated plans.
In certain cases they operate as an intermediary for
the activation of scenarios or services. The personal
assistants will usually be deployed over the users’
mobile devices. The specialized assistants are usually
located on the server nodes of the VES, known as
operatives. They support the execution of the plans
generated by the personal assistants; therefore they
implement suitable interfaces to the available
electronic services and data repositories. Operatives
serve two subspaces, known as DiLibs-Subspace and
Admin-Subspace respectively. Guards are special
assistants which are responsible for the safety and
efficient execution of the plans in the space. These are
usually intelligent devices that react to various
physical quantities in the environment, e.g. smoke,
temperature, humidity. The guards act as an interface
between the physical and the virtual world in the
space.</p>
      <p>VES is “populated” only by active components
known as assistants. Each assistant has to play a role
in accordance with its delegated responsibilities. The
responsibilities (tasks) are implemented or delivered
by electronic services. The electronic services
themselves cannot be separate operational
components of the space because they are suitable for
the implementation of business functionality but are
static without having the properties to be
contextaware and intelligent. The assistants themselves
implemented as bounded rational agents are active
context-aware intelligent components that support the
planning, organization and implementation of the
educational process.</p>
      <p>Two subspaces are maintained in the VES:
•</p>
      <p>Digital Library Subspace (DiLibS) – the
digital libraries are specialized repositories
where mainly educational content is stored.
Furthermore, the operatives of that subspace
realize interfaces to three components
supplied to the space by DeLC – SCORM
2004 Engine, Test Engine (QTI 2.1.
compliant) and Event Engine.
• Admin-Subspace – it supports all activities
related to the organization, control and
documentation of the education process. In
the administrated database is stored all the
necessary useful information for planning,
organizing, protocoling and documenting the
educational process such as school plans,
programs and schedules, protocols of
examinations, and gradebooks.</p>
      <p>The two subspaces are supported by a common
platform known as DiLibS platform briefly presented
in the next section.</p>
    </sec>
    <sec id="sec-3">
      <title>3. DiLibS Platform</title>
      <p>The platform is built as a dynamic web application
distributed in two main areas – an education portal
operating as a specialized user interface and server
side (Figure 2.). Both areas communicate by using
pure HTTP requests, RESTful services and Web
Sockets. An application in the browser consists of a
pure HTML 5 and CSS 3 implementation combined
with dynamics provided by JQuery and
responsiveness delivered by Bootstrap.</p>
      <p>At the server side, the core services provided by
the platform include the minimal functionality needed
for the majority of the current web applications:
• Security – it implements the security
mechanism with per roles, per groups and
per users’ rules;
• Web Content – it allows a definition of static
web content;
• Control Panel – the management of the
above services, the plugins, and so on.</p>
      <p>There are also two additional services that are
provided by the platform at a lower level:
• Message Queue – it is used by all the plugins
and core services as a message bus for
asynchronous communication between the
different components;
• ORM Layer – an object-relational
transformation layer that is used by all
components for communication with the
database.</p>
      <p>ExtJS</p>
      <p>JQuery</p>
      <p>Bootstrap
HTTP</p>
      <p>REST</p>
      <p>Web Socket</p>
      <p>SCORM
Engine</p>
      <p>Test
Engine</p>
      <p>Teacher
Notebook</p>
      <p>Grade
Book</p>
      <p>P/O/D</p>
      <p>…</p>
      <p>Hibernate
Message Queue</p>
      <p>That platform is open for extension by using the
so-called plugins. Each plugin provides unique
functionality which is integrated in the portal
seamlessly. Currently, several plugins in a different
state of completion are supported by the platform.</p>
      <p>The core of the platform is Digital Library which
stores educational content. Basically, the content is
prepared in accordance with the SCORM 2004
standard, but storage in other formats is also possible
(.pdf, .ppt, .doc).</p>
      <p>The data model (Figure 3) allows storage of static
and dynamic content in the library. The static content
is actually references to real files in the file system. In
this way the database is not affected by the size of the
static files. The dynamic content consists of the
SCORM packages deployed in the system and the
QTI content, which is related to the assessment
subsystem.</p>
      <p>The content of the current version of the Digital
Library is organized in a hierarchical structure
composed by sections. Each section can have mixed
content – other sections (subsections) and/or
resources (static and dynamic). In addition, the
Digital Library provides a flexible security
mechanism. It allows the definition of cascading
access rules per users, roles and/or role groups. There
are three different access rights: view, download and
manage, each of which with several access levels.
The access rules can be defined for a section and
cascade down to all subsections in the subtree of that
section. The final set of access rules for a section is
composed by a union of the cascaded rules, set by its
supersection, with its own rules (if any). This model
allows providing the users only with the resources
that are relevant for them (based on roles, role groups
or a person) and swipe the rest of the content, which
is part of the personalization concept.</p>
    </sec>
    <sec id="sec-4">
      <title>4. DiLibS in Practice</title>
      <p>The whole education of students in the Master's
degree program of Software Engineering is planned
and conducted in accordance with DiLibS. The
platform is used partially in the teaching at the
undergraduate programs in Informatics at FMI at
Plovdiv University, in the Master program of
Business Informatics and English, and the Master’s
degree program of Software Engineering at the Free
University in Burgas. At present, more than 2100
students and 18 teachers are using the platform.
DiLibS provides educational content in 13 subjects of
the Master program and 7 subjects of the Bachelor’s
degree program.</p>
      <p>
        The basic educational services supported by the
platform are the following:
• Self-Paced Learning – This service delivers
educational content for self-study of
students, usually in the form of SCORM
2004 electronic packages. The SCORM
Engine, consisting of SCORM Player,
SCORM Manager and SCORM Statistics
modules, is implemented according to the
ADL’s SCORM 2004 R4 specification [
        <xref ref-type="bibr" rid="ref13">14</xref>
        ].
SCORM was developed to support the
creation and portable delivery of reusable
teaching content for self-spaced
computerbased training. In our case, the teaching
material is stored in a digital library that can
be accessed by the students during their
selfstudy. The SCORM Engine traces the
progress of the students actually working
with the content. The collected information
is delivered to the teacher for analysis and
evaluation of the students' performance.
      </p>
      <p>
        E-testing – The Test Engine is the most
commonly used service in the real teaching
process at the Faculty of Mathematics and
Informatics at Plovdiv University. The
access to the functionalities of the engine is
provided by web services for managing,
assessing and analyzing digital assessment
content. These services are in direct
communication with multi-agent content and
an assessment management system that is
responsible for providing the digital
information resources requested by users via
the web services from the service layer of
the Test Engine. The Assessment Agent
System manages the digital content by using
the provided REST web services for
database access to acquire it and cooperative
work between the existing agents for its
processing. The digital assessment content
that the engine manages is designed as a
final specification fully compliant with the
QTI 2.1 [
        <xref ref-type="bibr" rid="ref14">15</xref>
        ]. Defining in such a way the
architecture and its provided services
facilitates a wide range of opportunities for
integrating the proposed Test Engine in the
space.
      </p>
      <p>
        Grade book – the student’s grade-book stores
and analyzes information on the success rate
of students in all the studied courses. It is
currently being developed in accordance
with the Grade Book specification, which is
included in the Common Cartridge standard
[
        <xref ref-type="bibr" rid="ref15">16</xref>
        ].
      </p>
      <p>Teachеr’s notebook – it is designed for the
analysis of the success rate of students in a
particular course of studies. In addition, it
helps the teacher to organize his/her duties
during the current education period (it is
being developed at present);
Services for planning, organizing and
documenting the learning process, including
different registration services, etc.</p>
      <p>We will demonstrate the practical use of the
system with two examples – the Software
Engineering course and the English language course.</p>
      <p>One of the SCORM e-learning content packages is
in Software engineering (Figure 4). This package is
organised in different sections that cover a specific
pedagogical model. After each part of the e-learning
content students have to pass a test. When the
students have passed the specific test, the next section
of the package is opened. This structure is realized by
sequencing and navigation technology in the SCORM
standard. Based on the students’ results some
statistics are collected – how many students have
passed the package, what percentage of the content
has been covered, etc.</p>
      <p>Figure 5. An example of open and closed questions
on a self-study test</p>
      <p>DeLC is integrated in the English language
education at the Faculty of Mathematics and
Informatics at Plovdiv University by means of the
Etesting system. This system is used both for
summative assessment in the classroom during the
term and at the end of the course, and for formative
assessment in the foreign language outside the
classroom. The medium of self-study tests allows for
acquisition and reinforcement of knowledge and skills
in a relaxed atmosphere in the students’ own homes.
Self-study tests are administered online – they are
published on the DeLC website to help learners to
practice what they have learned in the classroom
within a validity framework and a time limit set by
the teacher. Their content is relevant to the most
recent study materials and activities performed during
the academic classes. In order to gain maximum
benefit from the self-study tests and achieve best
results, students are allowed to redo them as many
times as needed, in case they are not happy with their
performance. The E-testing system makes use of
multiple-choice questions (MCQs) with one correct
answer, MCQs with more than one correct answer,
strict matching (where the number of questions
corresponds exactly to the number of answers),
nonstrict matching (the number of questions does not
correspond to the number of answers), and open
questions (Figure 5.).</p>
      <p>All self-study tests have the same structure and
method of scoring. The grades that students are given
(from the lowest grade of Poor 2 to the highest of
Excellent 6) correspond to the number of points that
they obtain from all test questions (Figure 6.). Closed
questions are graded automatically while long-answer
open questions are evaluated by the teacher and those
points are added later to form the student’s final
grade. Self-study tests are activated on a regular
weekly basis in immediate succession of the
academic classes at university which allows students
to become well acquainted with the types of activities
used for their final course assessment. They provide
educators with essential information which can be
used to make decisions about instruction and student
grades.</p>
      <p>Below are some of the advantages of using the
Distributed E-Learning Centre as a medium for
selfstudy tests:
• It is very user-friendly. It allows for various
types of tasks including the upload of
pictures and graphics and makes use of
metadata which facilitates the compilation of
tests on the basis of different criteria.
• The preview option helps teachers to try out
the test and make changes before its actual
administration to students.</p>
      <p>DeLC offers the option to set a time limit
and different validity periods for every test.</p>
      <p>Self-study tests are done online from the
comfort of students’ homes at a convenient
time within the framework of the test
validity.</p>
      <p>All questions are placed on one and the same
page which facilitates scrolling through the
various tasks to review, edit and correct
items.</p>
      <p>Students obtain their test results immediately
except for the open question scores which
are added after the teacher has evaluated the
texts.</p>
      <p>Students can check the grades they have
obtained on previous tests from their
accounts.</p>
    </sec>
    <sec id="sec-5">
      <title>5. Conclusion</title>
      <p>In this paper is presented an intelligent,
contextaware, scenario-oriented and controlled infrastructure
known as Virtual Education Space. The kernel of the
space, the DiLibS platform, is implemented for the
provision of teaching material and eLearning services
according to the SCORM 2004 and Common
Cartridge (QTI 2.1., Grade Book) standards. The
DiLibS platform is created through re-engineering of
the existing environment DeLC. Currently, our effort
is focused on expanding and strengthening the
platform with intelligent assistants. In addition, a
workplace for teachers is developed providing
specialized editors for the preparation of teaching
material and electronic tests.</p>
    </sec>
    <sec id="sec-6">
      <title>6. Acknowledgments</title>
      <p>The authors wish to acknowledge the partial support
of the NPD – Plovdiv University under Grant No.
NIFMI-004 “Innovative Basic and Applied Research in
Computer Science, Mathematics and Pedagogy
Training”, 2015-2016 and Grant No. IT15-HF-001
“Improving the Access to Educational Services in the
Context of Lifelong Learning”, 2015-2016.</p>
    </sec>
  </body>
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