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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Evaluating accessible adaptable e-learning</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Christopher DOUCE</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Wendy PORCH</string-name>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Institute of Educational Technology, Open University</institution>
          ,
          <country country="UK">UK</country>
        </aff>
      </contrib-group>
      <fpage>64</fpage>
      <lpage>73</lpage>
      <abstract>
        <p>Two different approaches can increase the accessibility of digital educational materials: content that has been built with the widest possible set of users in mind (universal design), or content that has been designed in such a way that it can be personalised to individual user needs and preferences (personalised design). This paper outlines a number of approaches that could be used to evaluate the provision of learning materials that have been adapted to or chosen for individual learners. A number of different perspectives are considered in this paper: a learner's perspective, the perspective of the tutor or teacher, and an institutional perspective. A number of complementary methodologies are presented. It is argued that the evaluation of a system that provides personalised learning content is a challenging activity that necessitates the application of multiple methods to effectively understand the underlying costs and benefits of providing personalised learning materials.</p>
      </abstract>
      <kwd-group>
        <kwd />
        <kwd>accessibility</kwd>
        <kwd>elearning</kwd>
        <kwd>evaluation</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>Introduction</title>
      <p>The emergence of tools such as virtual learning environments has enabled institutions
to create digital services that can be used to augment face-to-face teaching. Learners
can increasingly access a wealth of digital learning resources that can either help
students become familiar with the subjects that are going to be discussed before a
lecture or class, or allow learners to consolidate concepts that were taught during a
lecture.</p>
      <p>The development of these new technologies can, to a varying degree, be
considered to be especially beneficial to learners with disabilities. Those students who
are unable to attend a class may be able to use a virtual learning environment to make a
contribution by participating within on-line activities. The accessibility of learning
technologies ultimately depends upon the accessibility of the tools that are used to
present learning materials (such as a VLE) as well as the learning material it contains.</p>
      <p>Digital learning materials (or content) can be presented in a multitude of different
formats. Digital content can be in the form of simple web pages, audio pod casts,
fragments of video, or even interactive demonstrations such as simulations. The choice
of what format to use may depend upon a wide range of factors, including the learning
objectives that the educator aims to convey the availability of appropriate digital
resources from a third party, the amount of time that an educator or learning
technologist could spend creating those resources, and levels of internal expertise.</p>
      <p>Although a range of digital resources can be created and presented through a
virtual learning environment, there is a risk that some of the content may be
inaccessible for certain groups. A visually impaired user may not be able to benefit
from the provision of a video resource if it does not contain additional audio
descriptions or other complementary materials. Similarly, a learner who has an
auditory impairment may not be able to take advantage of a pod cast if the pod cast
does not have an accompanying transcript.</p>
      <p>The accessibility of learning material for learners who have disabilities rests upon
representatives from an educational institution making practical decisions to ensure that
no students are disadvantaged in terms of either being able to ‘access’ the materials
through a preferred modality, or being disadvantaged through the adoption or use of
learning objectives that makes their academic achievement difficult or even impossible.</p>
      <p>The next section of this paper introduces the notion of content personalisation and
adaptation as a way to enhance the accessibility of digital learning resources. This is
contrasted with the competing notion of universal design: the ideal that all products,
resources or systems should be accessible and usable by all people.</p>
      <p>Within an educational institution, many different people have a collective
responsibility regarding the provision of accessible learning. A number of groups or
people who are acknowledged to have a responsibility are highlighted in the
stakeholders section.</p>
      <p>
        The focus of this paper lies with understanding how to evaluate whether it may be
possible to deploy or develop a successful content personalisation approach to deliver
the best possible educational experience for the widest possible group of learners. The
EU4ALL project aims to build a practical framework to demonstrate the operation and
potential benefits of content personalisation and other processes that can enhance the
provision of accessibility [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]. A number of possible evaluation methods are presented
within the methodologies section. This is then complemented with a discussion. The
paper then concludes with a set of practical suggestions about how the EU4ALL
framework and its content personalisation functionality can be evaluated.
      </p>
    </sec>
    <sec id="sec-2">
      <title>1. Content personalisation and adaptation</title>
      <p>There are two fundamental approaches for the development of accessible resources.
The first is the development of a resource that is universal, i.e. a digital resource that all
learners can use, regardless of their disability or sensory impairment. A video may be
designed in such a way so that all the themes and principles it presents can be
explained through the audio track with any accompanying visual descriptions merely
emphasising the points that are being made. For the video to be accessible for people
with hearing impairments, a set of subtitles may simultaneously be presented. This
means, that the learning resource could be useful to people who have either visual or
auditory impairments. In this way, such a video may be considered a product of
universal design.</p>
      <p>One argument against universal design is that learning resources that can be used
by all people may not be optimal for everyone: each learner may have their own precise
learning needs and requirements since each learner may have a unique combination of
skills and disabilities. An alternative to the ideal of a universal resource is the notion
of personalised or adaptable resources. A digital resource could be designed in such a
way so it could be adapted (or customised) to match the needs and preferences of
individuals. Some learners may prefer to listen to spoken versions of learning content
due to a learning style preference. Some learners, on the other hand, may require
subtitles of a particular size, colour, font or speed. Other learners may find that a
transcript of a video might be more useful, since it can be more readily edited or
manipulated.</p>
      <p>
        The EU4ALL and TILE [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] projects have both attempted to explore the
practicalities and challenges inherent with the creation of a system that enables
educational materials and user interfaces to be adapted to the needs of individual users.
The TILE project, an abbreviation for The Inclusive Learning Exchange, aimed to
implement and explore an emerging generation of learning technology standards.
Using a simple user interface that is akin to a ‘wizard’ end users (or learners) can
specify a range of different content preference settings that suited their personal needs.
Users can specify what media types are preferred, whether video resources are to
contain subtitles or additional audio descriptions, for example. The TILE system
would then choose and deliver resources that were suited to the preferences associated
to a particular learner.
      </p>
      <p>EU4ALL project has created a framework that can facilitate discussion about how the
accessibility of virtual learning environments and e-learning systems in general might
be improved, developed and enhanced. The EU4ALL framework can also be
practically implemented through its proposed adoption of a service-oriented design and
use of a new generation of learning technology standards. As a result, the framework
has the potential to be used by a range of different VLE systems that can eventually
deliver personalised e-learning to different users.</p>
      <p>The EU4ALL framework comprises of a number of distinct components. The
VLE system is used to store digital learning resources. Information about the
accessibility of the resources is held within a component known as the Metadata
Repository (MR). The accessibility information is represented in terms of whether a
particular resource is appropriate for a particular modality. Information about the user
is held within the User Model (UM). The choice of the content that is appropriate to
the user is performed by the content personalisation module (CP). The EU4ALL
framework offers other components that are discussed elsewhere, a Device Model
(DM), a Recommending System (RS) and an E-Services Server (ESS) which provides
accessibility provision administrative support in the form of workflow services.</p>
      <p>
        It should be stated that there are some parallels that can be drawn between
EU4ALL and the ADAPT2 architecture [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]. Similarities can be seen in the application
of a user modeling component and the fact that a structured ontology has been used to
attempt to describe the different services that the ESS component could represent. Key
differences relate to the application and combination of different learning technology
standards and a clear and distinct focus towards the important issue of accessibility.
      </p>
      <p>The learner interface to the system is facilitated through the link to the Virtual
Learning Environment (VLE). Other external information systems can be connected to
the EU4ALL framework, hence the link to an external ‘Staff Intranet’, where
administrative personnel can gain access to other components, such as performance
statistics that are produced by the ESS.</p>
      <p>Different components of the EU4ALL framework have been implemented by
different project partners. The User Modeling (UM) and Recommending System (RS)
has been implemented by the aDeNu (Adaptive Dynamic online Educational system
based oN User modeling) research group which are situated at the Universidad
Nacional de Educación a Distancia (UNED) of Spain. The metadata repository has
been developed by a commercial partner, ATOS Origin, and the content personalisation
component has been implemented by an organisation called Indra. A substantial
challenge lies with ensuring not only that all the individual components work together,
but also to ensure that the end result from the entire system is of benefit to learners and
different institutional stakeholders.</p>
    </sec>
    <sec id="sec-3">
      <title>2. Stakeholders</title>
      <p>The use, availability and presentation of accessible digital resources requires
cooperation between different stakeholders. Whilst a single teacher or educator may be
able to upload their own notes or presentations to a VLE which may be accessible in
their own right, the availability and accessibility of the VLE is dependent upon a
number of other people. The following table describes a number of important
stakeholders who guide the development and provision of accessible e-learning. The
names of the stakeholders are designed to be ‘high level’ groupings that can be used to
guide discussion about the various roles and responsibilities. The notion of an
academic manager, for example, can be represented by either a dean (a head of a
faculty), or a head of a department.</p>
      <p>Provides tutor, lecturer and other technical staff guidance about how to best
make use of different formats and learning technologies. Can have training
responsibilities to ensure that staff are familiar with the operation of new
technologies.
System Developer
System Administrator
Disabilities Advisor
Academic Manager
Principle</p>
      <p>A software specialist who is responsible for developing and enhancing the
operation of one or more learning technologies. The developer needs to have
an awareness of the importance of accessibility and is likely to liaise with the
learning technologist and system administrator.</p>
      <p>Responsible for deploying and ensuring continual operation of learning
technologies that have been selected by the learning technologist and/or
lecturing staff. Liaises with other technology personnel to ensure continual
network operation and service. Also provides security support and backup
services.</p>
      <p>Offers institutional guidance to individual learners. In some institutions this
stakeholder may be split amongst a number of roles, including needs
assessments and sourcing of appropriate assistive technologies that are to be
supplied to tutors.</p>
      <p>Line manager for individual lecturers or tutors. In terms of lecturers, the
academic manager may be a head of a department or a dean, for example.</p>
      <p>For tutors (within the Open University), the line manager would be called a
staff tutor. The academic manager may need to be aware of support issues
and be able to make available resources to facilitate the provision of
accessible learning.</p>
      <p>Individual or group that is responsible for the operation of an institution.</p>
      <p>Principle has responsibilities for adhering to national and international
legislation and developing organisational structures that permit the delivery
of accessible learning.</p>
      <p>This table is by no means complete and its precise constituents will vary depending
upon the differences between institutions. All of these stakeholders have a role to play
regarding the delivery of accessible learning experience.</p>
      <p>Given a similar list of stakeholders, a substantial question that should be asked is:
will these stakeholders accept the development or the delivery of a system that presents
learning materials that are personalised to the needs of individual learners? The
following section aims to consider what evaluation methodologies could be used to
uncover what issues or barriers may prevent the acceptance or development of the a
personalised approach to accessibility.</p>
    </sec>
    <sec id="sec-4">
      <title>3. Evaluation Methodologies</title>
      <p>To understand the complexity of introducing a system that personalises learning
material requires the application of a number of different evaluation methods. The
choice of the method depends upon the question that is to be assessed, and this varies
between the perspectives held by each of the stakeholders. A learner will hold a
different perspective than the tutor, or the principle, for example.</p>
      <p>This section presents a brief description of the different methods that could be used
to evaluate the EU4ALL framework (outlined in figure 1) and its content
personalisation functionality.</p>
      <sec id="sec-4-1">
        <title>3.1. Software Inspections</title>
        <p>A software inspection, also known as a code review, is where the internals of a
software system are shared between a number of different developers who then debate
its internal design and quality, drawing upon prior experience of other systems. Issues
discovered as a result of applying this method are likely to be discussed and any design
flaws may be either addressed or recorded for further consideration. It is possible that
this approach could be modified to facilitate the inspection or internal evaluation of an
accessible adaptable resource.</p>
      </sec>
      <sec id="sec-4-2">
        <title>3.2. Automated Checking</title>
        <p>
          Automated checking tools can be used to provide guidance about whether digital
resources conform to a number of well known accessibility guidance. Tools, such as
the Imergo web compliance manager [
          <xref ref-type="bibr" rid="ref4">4</xref>
          ] can be used to provide resource designers and
development an indication as to whether they have missed any important issues and
indicate, in some cases, whether assessment is necessary to complete checking. The
W3C Web Content Accessibility Guidelines [
          <xref ref-type="bibr" rid="ref5">5</xref>
          ], however, are oriented towards the
principle of universal accessibility. When interpreting the results from automated
checkers, the needs and preferences of the individual to which a particular resource
may relate to should be taken into account.
        </p>
      </sec>
      <sec id="sec-4-3">
        <title>3.3. Heuristic Evaluations</title>
        <p>
          A heuristic evaluation is a recognised human-computer interaction technique that aims
to quickly identify usability problems with an interactive device by asking usability
experts to assess an interface using a number of known usability principles [
          <xref ref-type="bibr" rid="ref6 ref7">6, 7</xref>
          ]. A
heuristic evaluation is likely to be useful to evaluate the interface that a student uses to
gain access to the learning material that is then personalised. The approach can also be
used to evaluate the interfaces that tutors, lecturers or administrators use to add or
change learning materials that are presented to end users.
        </p>
      </sec>
      <sec id="sec-4-4">
        <title>3.4. Predictive Evaluations</title>
        <p>
          Predictive evaluations represent a range of techniques that are designed to predict the
performance or the effect of a design change. A well known predictive technique is
called GOMS [
          <xref ref-type="bibr" rid="ref7 ref8">7, 8</xref>
          ]. The amount of time a user may spend on a particular screen or
page is estimated in terms of time allocated to the analysis of elements that can be
found on a screen. The length of time attributed to the execution of actions (such as
menu choices or mouse clicks) can also be estimated. The resulting data can be used to
provide clear information about the effectiveness of one design over another.
        </p>
      </sec>
      <sec id="sec-4-5">
        <title>3.5. End-user Evaluations</title>
        <p>A difficulty with predictive evaluation is that they do not take into account differences
between users. A difficulty of heuristic evaluations is that experts may fail to find all
usability problems, or alternatively find usability problems that do not exist (known as
a false positive). Evaluating a system with real users allows researchers to gain an
indepth understanding of real difficulties that are faced, given a particular task or activity.
End-user evaluations are often carried out after a series of heuristic evaluations have
been completed since they are considered to be both expensive and time consuming.
This said, end user evaluations are considered essential to uncover accessibility
problems.</p>
      </sec>
      <sec id="sec-4-6">
        <title>3.6. Field Evaluations</title>
        <p>
          Whilst end-user evaluations are usually carried out within a laboratory, field
evaluations are carried out in the situation where a product or system is likely to be
used [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ]. If a virtual learning environment is to be primarily used at home, a field
evaluation will take account of whether the system is appropriate for the environment
in which the system inhabits. Field evaluations have the potential to illustrate the
impact of issues such as personal assistive technology and operating system
preferences on the usability and accessibility of a system. Field evaluations may
involve an observer, or may involve end users making diary entries at either critical
events or certain points throughout the day to record observations and current activity.
Field evaluations are also useful to understand how tutors and lecturers may create their
own learning material, and whether a system needs to change or offer alternative
functionality to help the user with their tasks.
        </p>
      </sec>
      <sec id="sec-4-7">
        <title>3.7. Pedagogic Evaluations</title>
        <p>
          Pedagogic evaluations aim to assess whether a system (or a pedagogic practice) can
facilitate learning. Assessment of learning is usually carried out through a test or task
that has been designed to explore whether certain principles or knowledge has been
retained. The effectiveness or performance of a learning tool, system or practice may
be demonstrated by offering pre and post ‘learning task’ tests to participants. Control
experiments can be used to explore the effect or power of a particular system. Whilst
test scores can provide a quantitative assessment of learning, a complementary
qualitative approach is to explore the attitudes or perceptions learners hold regarding a
system. Learners could be asked if they felt that one system was better than another in
terms of usability or accessibility. More detailed questions, presented in terms of
usability and user experience goals, [
          <xref ref-type="bibr" rid="ref7">7</xref>
          ] may be able to assess whether a system could
either positively or negatively interfere with learning activities and tasks.
        </p>
      </sec>
      <sec id="sec-4-8">
        <title>3.8. Economic Evaluations</title>
        <p>A substantial evaluation consideration should be whether or not a new system is likely
to be cost effective either in terms of how much time a system takes to operate, or how
much money it could cost to implement and maintain. These financial dimensions can
be implicitly seen within some of the other evaluation approaches. The predictive
evaluation method aims to proportion time against elements of an interface. The act of
conducting a user evaluation (with either the tutor or a learner) may indicate clearly
that certain tasks may be difficult to understand. In yielding such a response, it may be
possible to conclude that a system may be costly to use, and increase the risk of it not
being used or accepted. A thorough economic evaluation in terms of whether any new
system can be connected to an existing information technology infrastructure is also
necessary. If, from a maintenance perspective, rework or redevelopment of existing
systems is necessary or the purchasing (and operating) of additional hardware, the
management personnel within an organisation need a clear picture about its underlying
costs and benefits.</p>
      </sec>
      <sec id="sec-4-9">
        <title>3.9. Perception Evaluation</title>
        <p>It is important to take into account the attitudes that the various stakeholders may hold
towards the proposed system since this is likely to influence whether it is likely to be
accepted, regardless of whether or not the system is likely to improve the learner
experience. Perception evaluation, as it is called here, can be carried out by carrying
out a series of stakeholder interviews. If the new system requires the mobilization of
additional resources to ensure that the system can be effectively deployed, this
technique will help the attitudes relating to such issues to be explored. It may be
possible to mitigate against challenging attitudes by presentation of end user
experiences, current legislation and potential benefits to the institution as well as to end
users.</p>
      </sec>
    </sec>
    <sec id="sec-5">
      <title>4. Discussion</title>
      <p>The comprehensive evaluation of a new system (or framework) like EU4ALL that aims
to deliver learning materials and services that are customised to an individual’s needs
and preferences is a considerably challenging task. Not only are there a number of
different methods and approaches that could be used, there are also a wide and varied
number of stakeholders whose views must all be taken into consideration.</p>
      <p>The end users perspective is essential when it comes to understanding the
difficulties that learners face when interacting with a system. The difficulty of using a
system is likely to go hand in hand with the task that a system is used for. Whilst
consuming content that has been personalised for a learner may be an activity that
could be straightforward, there are significant challenges in understanding how
lecturers and tutors might be encouraged to create materials that can be ‘personalised’
when the task of a lecturer is not to create personalised content, but to lecture or to
teach. As a result, any system that allows personalised content to be authored must be
as easy to use as possible. One of the challenges of evaluation is to find an approach
that enables some of the key difficulties to be identified. When issues are identified,
their usability or accessibility could be further developed, or tasks could be reduced in
complexity.</p>
      <p>Another key issue that must be remembered when conducting an evaluation of any
system is the issue of ethics. This issue is particularly significant when we begin to
consider the issue of pedagogic evaluations. Consider the example of constructing an
experiment where there are two systems: one system that provides learning materials
that are universally accessible, another system that may be personalised to an
individual’s needs and preferences. If both systems were deployed in a formal
educational setting, it may be possible to argue that one student may have an advantage
over the other if the system that is the subject of the evaluation is considered to be
ultimately successful. The key, of course, is to always ensure that the participant is
always considered to be the most important element of an evaluation. The technology
that may be the ultimate focus of a series of studies should always be of secondary
importance. It should be unambiguously stated that any evaluation should not be
connected with a formal course or qualification. Should a pedagogic evaluation be
considered to be required, it may be necessary to create a set of learning materials that
are representative of those that may be found within a real course. One of the
challenges is to create materials that are interesting enough to persuade participants to
become involved with the evaluation.</p>
      <p>A further challenge inherent when performing the evaluation of any
recommendation or content personalisation system is to assess how the system may be
deployed or used within an existing system. To build a complete picture and to learn
what must be done in order for real institutions to adopt the proposed approach,
consultation with administrative and managerial stakeholders will be necessary. Since
the structures of organisations differ, it is suggested that stakeholders from a number of
different institutions are consulted. One approach to efficiently gather information
relating to the subject of deployment is to carry out a series of focus groups or
workshops to assess the political, economic, social and technological (PEST) barriers
for acceptance.</p>
      <p>The process of evaluation is likely to point towards the ways in which the
framework may be applied within a large organisations, such as the Open University.
From one perspective, EU4ALL can be seen as technical framework that can guide the
practical implementation of new learning technologies and enhancements to existing
VLE systems. From a different perspective, it can be used as a tool to uncover the way
that information technology can enhance the provision of services to people with
disabilities.</p>
    </sec>
    <sec id="sec-6">
      <title>5. Conclusion</title>
      <p>To summarise, a multi-method approach is necessary to comprehensively evaluate the
acceptance of a new accessibility framework that contains a content personalisation
component. It is necessary to evaluate the perspectives of both the learner and those
who are responsible for creating new adaptable (or customisable) digital resources. It
is also necessary to assess the extent to which a system may be integrated with and
connected to an existing infrastructure. A number of different evaluation approaches
can be drawn upon. The following practical activities are suggested:
1.
2.
3.
4.</p>
      <p>Conducting heuristic evaluations of initial interfaces to assess the efficiency of
proposed interfaces.</p>
      <p>Complement heuristic evaluations with automated testing of digital resources,
taking account of end user profiles.</p>
      <p>Complement heuristic evaluations with a series of usability tests.</p>
      <p>Design a series of qualitative pedagogic evaluations and liaise with internal
pedagogic evaluation experts to assess the effectiveness of their design.
Carry out a series of workshops for senior stakeholders that aim to uncover the
complexities inherent in supporting the delivery of accessible material and
services.</p>
      <p>By conducting a combination of these approaches, it is hoped that a rich understanding
of the complexities inherent in developing and deploying a framework that contains a
content personalisation system will emerge. The resulting lessons can then be used to
offer feedback into further designs and be used to inform how most effectively offer
mechanisms that can support the provision of accessibility services to further and
higher education institutions through the application of information technology.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <surname>Douce</surname>
            ,
            <given-names>C. R.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Porch</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Cooper</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          &amp;
          <string-name>
            <surname>Heath</surname>
            ,
            <given-names>A.</given-names>
          </string-name>
          <article-title>European Unified Framework for Accessible Lifelong Learning</article-title>
          .
          <source>Fourteenth International Conference for the Association of Learning Technology Conference (ALT-C)</source>
          , Nottingham University, Nottingham,
          <string-name>
            <surname>UK</surname>
          </string-name>
          , (
          <year>2007</year>
          )
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <surname>Treviranus</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          and
          <string-name>
            <surname>Brewer</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          <article-title>Developing and Reusing Accessible Content and Applications, in Reusing Online Resources: A Sustainable Approach</article-title>
          to eLearning, (Ed.) Allison Littlejohn.
          <source>Kogan Page</source>
          , London,
          <year>2003</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <surname>Brusilovsky</surname>
            ,
            <given-names>P.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Sosnovsky</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Yudelson</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          <article-title>Ontology-based framework for user model interoperability in distributed learning environments</article-title>
          . In: G. Richards (ed.)
          <source>Proceedings of World Conference on E-Learning, E-Learn</source>
          <year>2005</year>
          , Vancouver, Canada,
          <source>October 24-28</source>
          ,
          <year>2005</year>
          , AACE,
          <fpage>2851</fpage>
          -
          <lpage>2855</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <surname>Chisholm</surname>
            ,
            <given-names>W.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Vanderheiden</surname>
            ,
            <given-names>G.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Jacobs</surname>
            ,
            <given-names>I.</given-names>
          </string-name>
          <year>1999</year>
          .
          <article-title>Web content accessibility guidelines 1.0</article-title>
          . http://www.w3.org/TR/WCAG10, accessed
          <issue>8 April 2009</issue>
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          <article-title>[5] Imergo accessibility checker</article-title>
          , http://www.imergo.com/, accessed 8 April 2009
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <surname>Nielsen</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          , and
          <string-name>
            <surname>Molich</surname>
            ,
            <given-names>R.</given-names>
          </string-name>
          <article-title>Heuristic evaluation of user interfaces</article-title>
          ,
          <source>Proc. ACM CHI'90 Conf</source>
          . (Seattle, WA,
          <fpage>1</fpage>
          -5 April), (
          <year>1990</year>
          ),
          <fpage>249</fpage>
          -
          <lpage>256</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <surname>Preece</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Rogers</surname>
            ,
            <given-names>Y.</given-names>
          </string-name>
          and
          <string-name>
            <surname>Sharp</surname>
            ,
            <given-names>H.</given-names>
          </string-name>
          <article-title>Interaction design: beyond human-computer interaction</article-title>
          , John Wiley &amp; Sons,
          <year>2002</year>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <surname>Card</surname>
            , Moran,
            <given-names>Newell.</given-names>
          </string-name>
          <article-title>The Keystroke-Level Model for User Performance Time with Interactive Systems</article-title>
          ,
          <source>Communications of the ACM</source>
          ,
          <volume>23</volume>
          , (
          <year>1980</year>
          ),
          <fpage>396</fpage>
          -
          <lpage>410</lpage>
          .
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>