<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Archiving and Interchange DTD v1.0 20120330//EN" "JATS-archivearticle1.dtd">
<article xmlns:xlink="http://www.w3.org/1999/xlink">
  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Cloud Services for Learning Scenarios: Widening the Perspective</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Marc Jansen</string-name>
          <email>Marc.Jansen@hs-ruhrwest.de</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Nelson Baloian</string-name>
          <email>nbaloian@dcc.uchile.cl</email>
          <xref ref-type="aff" rid="aff0">0</xref>
          <xref ref-type="aff" rid="aff1">1</xref>
          <xref ref-type="aff" rid="aff2">2</xref>
          <xref ref-type="aff" rid="aff3">3</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>H. Ulrich Hoppe University of Duisburg-Essen</institution>
          ,
          <addr-line>Duisburg</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>Ruhr-West University of Applied Sciences</institution>
          ,
          <addr-line>Bottrop</addr-line>
          ,
          <country country="DE">Germany</country>
        </aff>
        <aff id="aff2">
          <label>2</label>
          <institution>Universidad de Chile</institution>
          ,
          <addr-line>Santiago</addr-line>
          ,
          <country country="CL">Chile</country>
        </aff>
        <aff id="aff3">
          <label>3</label>
          <institution>University of Twente</institution>
          ,
          <addr-line>Enschede</addr-line>
          ,
          <country country="NL">The Netherlands</country>
        </aff>
      </contrib-group>
      <pub-date>
        <year>2012</year>
      </pub-date>
      <fpage>33</fpage>
      <lpage>37</lpage>
      <abstract>
        <p>-The term “Cloud Computing” does not primarily specify new types of core technologies but rather addresses features to do with integration, inter-operability and accessibility. Although not new, virtualization and automation are core features that characterize Cloud Computing. In this paper, we intend to explore the possibility of integrating cloud services with educational scenarios without re-defining neither the technology nor the usage scenarios from scratch. Our suggestion is based on certain solutions that have already been implemented and tested for specific cases.</p>
      </abstract>
      <kwd-group>
        <kwd>-Cloud Computing</kwd>
        <kwd>Cloud Services</kwd>
        <kwd>Scenarios</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>-</title>
      <p>INTRODUCTION</p>
      <p>
        Currently, Cloud Computing scenarios are often used to
overcome certain limitations of mobile devices, desktop
computers or server systems, especially to improve
accessibility and interoperability. Hereby, Cloud Computing
is usually subdivided into at least the three following parts
[
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]:
1. IaaS - Infrastructure as a Service: Virtual provision
of computing power and/or memory. A prominent
example of an IaaS service is the Amazon WS
service.
2. PaaS – Platform as a Service: Provision of a
runtime environment, like application servers,
databases etc. In this area, Googles App Engine is
probably the most prominent example.
3. SaaS – Software as a Service: Provision of usually
browser based applications that can directly be
used. Here, Google Docs or the Customer
Relationship Management software of
salesforce.com serves as examples.
      </p>
      <p>One aspect that is common to these three levels is the
high degree of automation that is pursued by these kinds of
Cloud Services. On the IaaS level, Cloud Computing can be
understood as virtualization technology along with a high
degree of automation, whereas PaaS provides a flexible way
for the deployment of applications and SaaS is able to</p>
      <p>AN ALTERNATIVE PERSPECTIVE ON CLOUD SERVICES</p>
      <p>WITH RESPECT TO LEARNING SCENARIOS</p>
      <p>In abstraction, Cloud Computing increases the flexibility
of modern applications while at the same time improving
security aspects such as availability, data storage or
communication. Furthermore, one major aspect in Cloud
Computing scenarios is the accessibility of the provided
services through a set of standardized services.</p>
      <p>
        With respect to learning scenarios, a different perspective
to these abstracted features of Cloud Computing services
(referred to in this paper as Cloud Services) offers a new
understanding of prominent services like Twitter or
Facebook. These Cloud Services can then be used as entry
points for value-adding functions both in formal and
informal learning settings, remote and co-located situations
and in synchronous or asynchronous scenarios. On the one
hand using such services allows getting into contact with
students on internet platforms where they spend a large
amount of their time [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ], and on the other hand, to use
offthe-shelf software [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ], which saves implementation efforts
and development time, but allows for using contributions
from the students via these different Cloud Services.
III. A SOFTWARE ENGINEERING PERSPECTIVE ON CLOUD
SERVICES FOR LEARNING APPLICATIONS
      </p>
      <p>
        The reuse of software components is one of the building
blocks of modern Software Engineering approaches. In [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ]
the authors state that the term “re-use” can be interpreted
somewhat differently with respect to Software Engineering
approaches for the field of Technology-Enhanced-Learning
(TEL). On the one hand, there is the re-use of content, which
seems to be fairly well accepted. On the other hand, there is
the re-use of both single software components as well as the
re-use of established and approved architectures. In contrast
to the re-use of content, these two more technical aspects of
re-use are not yet well accepted or used.
      </p>
      <p>Here, the usage of cloud services might help to either
increase the re-use of single software components, e.g.,
provided as Web Services, and the re-use of established and
approved architectures.</p>
      <p>Web Services, as one of the building blocks for modern
Cloud Computing environments, provide in themselves the
idea of providing re-usable software components. One view
to Web Services is that the major idea of Web Services is to
provide re-usable software components that are made
available through a set of standardized protocols. These
protocols support consumers of these Web Services through
the complete development cycle from finding a particular
service (e.g., in a UDDI repository), accessing the
description of the service interface (e.g., described in
WSDL) to consuming the service (e.g., by using protocols
like SOAP or REST). Therefore, the provisioning of Web
Services in itself already provides a big opportunity for
reusing single software components and by using the
mentioned standardized protocols, the re-use of these kinds
of software components is even possible beyond the borders
of a single organization, but the re-use of these services is,
from a technology point of view, also possible beyond the
borders of a single organization.</p>
      <p>
        This is particularly interesting for learning scenarios,
since in this area we do usually not have that many
commercially oriented organizations or research groups.
Instead, the different players are willing to share their
content as well as their developed services among each other
in order to foster collaboration among different learning
communities. Of course, when it comes to content re-use,
aside from the technological problems that are fairly easy to
solve by using Web Services, other problems such as the
ownership of the resulting learning outcomes and questions
about the right to re-use these learning materials arise, as,
e.g., discussed in [
        <xref ref-type="bibr" rid="ref9">9</xref>
        ].
      </p>
      <p>From an architectural point of view, Web Services allow,
due to their possibility of re-use, a completely new approach
to the architectural development of the resulting software,
and of course also for the resulting learning applications.
Here, the development of new software can be performed
based on an architecture that is usually referred to as a
Service-Oriented-Architecture (SOA). The building blocks
of a new software developed based on this architecture are
services (in our context usually Web Services). The major
idea of a SOA is to build new software based on a number of
already existing services. The overall task that a piece of
software should fulfill is usually split up into different
subtasks that are performed by a number of different, and
usually already existing, services. Later on, after completing
all the subtasks, the results of these subtasks are aggregated
into the solution of the overall task. The combination of the
different services that fulfill the subtasks and the
combination of the results if often referred to as
“orchestration” and the produced code is often referred to as
“glue code”. Using a SOA based architecture nowadays
changes completely the usual software development process
from writing yourself every piece of code (even with the help
of already developed API’s) that is necessary in order to
fulfill the task at hand, to finding services that support the
developer in solving the special task, the orchestration of
these services and providing/implementing the glue code that
allows to solve the current task. In this sense, the Cloud
Computing paradigm itself provides already a new approach
for the architecture of learning scenarios.</p>
      <p>Cloud services may also lead to an enrichment on the
content level: The matching of user (learner) needs to
available materials may draw on existing learner profiles,
e.g. in social or professional networks, in addition to
contentrelated of resources, possibly using semantic web
technologies. The added value over conventional learning
metadata approaches would be the open-ness and free
connectivity of the environment.</p>
      <p>Fig. 1. Different degree of re-use with different software
engineering approaches</p>
      <p>From a technological point of view, Cloud Computing
could be seen as the next consequent development step from
a SOA to an architecture that does not only allow the re-use
of content and services (in the terms of single steps in a
process), but additionally as the re-use of computational
resources. E.g. in an SaaS scenario a complete software stack
would be re-used, which is pretty close to the idea of a SOA
where basically single services are the major goal of re-use.
On the next level, in a PaaS scenario, not single services are
the target for re-use, but the infrastructure for running these
services can be shared by different consumers. Last but not
least, IaaS scenarios allow for re-using infrastructure on the
lowest technical level, e.g., the re-use/sharing of
computational resources (like virtual servers), network
resources and/or storage resources. Hence, Cloud Computing
allows to overcome the limitations that usually exist within
SOA’s, e.g., that the re-use is still limited to the content
and/or the services in terms of process steps, and allows to
provide re-use for the complete stack from single software
services to the technical layer of the network and the storage.</p>
      <p>The idea of understanding Cloud Computing as the
consequent next step of software engineering in order to
extend the re-usability to the level of not only re-using
software components but also infrastructure components, is
shown in Fig. 1.</p>
      <p>IV.</p>
      <p>EXAMPLE SCENARIOS INCLUDING CLOUD SERVICES
Keeping in mind the previously mentioned benefits of
Cloud Computing, services such as, e.g., Twitter and
Facebook, provide similar benefits to computer-supported
learning environments, e.g., by increasing flexibility,
availability and the accessibility of services through
standardized methods. Therefore, services as those described
above can also be understood as cloud services and can then
be used in learning scenarios in order to exploit the described
benefits of Cloud Computing based services. Integrating
cloud services as input channels.</p>
      <p>Our suggestion does not primarily aim at defining new
cloud environments for education. The idea is rather to
connect specific educational environments, e.g. around
virtual or face-to-face classroom scenarios, with existing
Cloud Services. A technical infrastructure to support this is
outlined in Fig. 1. The major task performed by this
infrastructure is to provide a certain abstraction for the
messages received through the different input channels, store
these messages and later allow a flexible message
visualization to be used in learning units.</p>
      <p>Browser
Channel
Twitter
Channel
Facebook
Channel
E-Mail
Channel
SMS
Channel
…</p>
      <p>Message
Abstraction</p>
      <p>Storage Engine
Visualisation
FIG. 2.ARCHITECTURE TO SUPPORT MULTICHANNEL INPUT</p>
      <p>
        This architecture is a generalization of an approach that
has been implemented and tested with certain specific cases
[
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. In the sequel, we describe some example scenarios
illustrating our understanding of the benefits that Cloud
Services might bring to learning scenarios. Here, we see
advantages in both, formal and informal learning settings. A
differentiation can additionally be made with regard to
synchronicity – contents can be generated and directly used
in class, e.g., to support face-to-face scenarios, to replace
moderation cards and flipcharts in individual and group
work. Contents can also be generated in class and used in a
future session.
      </p>
      <p>One particular strength of integrating this kind of cloud
services is that in addition to supporting and enabling the
scenarios described here, it also supports seamless transitions
between those scenarios. For example, it is intended to
motivate the learners in informal learning scenarios, to
contribute and make use of this content in a face-to-face
classroom situation in a fully integrated way. The following
subsections describe two scenarios which can be carried out
with the help of the mentioned Cloud Services in more
detail. Our basic approach is to use existing services to
create, collect and visualize students' contribution in various
educational settings and scenarios. These scenarios build
upon established learning and teaching scenarios; their
realization with the help of the before-mentioned Cloud
Services and the proposed architecture add flexibility in
time, space, synchronicity and re-usability of technology and
data.</p>
    </sec>
    <sec id="sec-2">
      <title>A. One-Minute Papers</title>
      <p>
        One-minute-papers are a flexible and efficient way of
collecting feedback from small and large groups of learners
in seminars or lectures (also refer to, e.g., [
        <xref ref-type="bibr" rid="ref5 ref6 ref7">5-7</xref>
        ] for details
and empirical findings on the method). Students are handed a
piece of paper with questions they have to answer in
(typically) one minute.
      </p>
      <p>
        Example questions may focus on the contents of the
seminar lesson, e.g., "What did I like?", "What was new to
me?", "What do I consider important?", "What have I
learned?" Furthermore, they may also ask for topics and
relationships that are still unclear to the learner. In doing this,
a personal dialogue is established between student and
teacher, which can be especially difficult to establish in
larger groups. According to Stead [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ], this may improve
student motivation.
      </p>
      <p>
        With the help of our approach and architecture, these
scenarios can be brought about by using any kind of
computational device (e.g. notebook, smartphone, tablet) and
the students' favorite input channels. Providing an
environment that enables a computer-supported variant of
the One-Minute Paper method brings relief to teaching staff
by saving time and material compared to the pen and paper
version. Students' comments can be easily organized,
compared, visualized and stored. Especially for larger
amounts of students, this is expected to ease the handling of
learners' feedback. First experiences on the use of a
webbased input service (available to smartphones, tablets and
notebooks) to realize the One-Minute paper method have
been recently described by Bollen et al. [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ].
      </p>
    </sec>
    <sec id="sec-3">
      <title>B. Supporting Self-Learning Phases</title>
      <p>Another application scenario is the support of
selflearning phases between classroom sessions. It is important
for students to be able to transfer the newly acquired
knowledge to situations in their everyday life. The discovery
of one’s own examples, together with a sensitivity for
similarities and applicability, does also ideally lead to a
deepening of knowledge and makes learning contents more
easily retrievable when needed.</p>
      <p>Tasks like this can appear in almost every domain at
every stage of a lecture, seminar or student project. Results
can be collected and visualized for an in-class usage. Besides
this, as mentioned before, students are regularly prompted to
report on situations and examples that illustrate the learning
content. Therefore, the learner would be able to contribute
and share examples for future sessions.</p>
      <p>As an example, which originates from first experiences
and trials, the learners' task was to relate a new topic in a
seminar with everyday life's experiences. The teacher
prepared sentence opener questions to guide the learners,
who had one week time to collect and communicate their
findings - using tablets, notebooks or smartphones and
wherever and whenever appropriate.</p>
      <p>Again, the proposed architecture allows for a flexible
generation and accumulation of students' contribution over
time, together with a visualization support that helps teachers
and students likewise organize and share results.</p>
    </sec>
    <sec id="sec-4">
      <title>C. Group discussion support</title>
      <p>
        As a third application scenario, we present a situation that
utilizes the described architecture in a synchronous,
colocated manner. In a classroom situation, the proposed
system can be used to visualize textual contributions that
have been created by the learners and sent from various
sources. These contributions are received and processed
immediately and can be presented with the help of a large,
shared display, e.g. by using a video projection. Similar
approaches have been described, e.g., by Liu and Kao [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ]
and by Bollen et al. [
        <xref ref-type="bibr" rid="ref12">12</xref>
        ].
      </p>
      <p>By these means, classroom discussions can be supported
in a way that can be beneficial in a number of ways:
• contributions can be formulated and submitted
without interference and influence from peers
• contributions can be submitted anonymously, which
can raise participation in controversial topics or for
more introverted persons
• the course and structure of a discussion can be made
explicit in a shared visualization
• discussion results can be stored for later (re-)use,
review and comparison</p>
      <p>Scenarios like those described above benefit from the
integration of Cloud Services by increasing interoperability
of peripheral devices. Heterogeneous Cloud Services like
Twitter and Facebook allow participation independent of
both location and time.</p>
      <p>V.</p>
      <p>INTEROPERABILITY AND SCALABILITY OF SCENARIOS
Important features of computer-supported learning
environments are interoperability and scalability towards
educational scenarios. Is a learning environment (or a set of a
interoperating environments) scalable a) against an
advancing number of different scenarios and b) against a
varying number of involved students? Is a learning
environment (or a set of learning environments) providing
interoperability between different education scenarios, i.e.
does it support smooth transitions between varying
scenarios?</p>
      <p>Most notably, computer-supported learning scenarios can
be categorized along the dimensions of
• time: Is the user's interaction within the scenario
considered synchronous or asynchronous?
• location: Are participating learners are co-located or
are they in remote places?
• Group scale: How many learners are interacting in
the given scenario?</p>
      <p>To give two examples, in this scheme, a classroom
discussion would be considered a synchronous, co-located
scenario in a large group. A collaborative modeling activity
between two learners using a shared workspace environment
would be a remote, synchronous scenario in a dyad. Fig. 3
illustrates the dimensions described above:</p>
      <p>Fig. 3. Dimension of educational scenarios</p>
      <p>Along these dimensions, we can further explain the
aspects of interoperability and scalability of
computersupported learning environments. We can regard an
environment being scalable, if it allows the realization of
scenarios along instances of the dimensions mentioned
above. We consider an environment being interoperable
between scenarios, if it allows smooth transitions between
instances of various scenarios.</p>
      <p>As an example, if an environment allows the collection
of learner's contributions individually over a period of time,
and is able to present these contributions using a shared
display in a classroom context, this environment is capable to
scale over time and group scales, and we may consider it as
being interoperable, if the transition between those scenarios
requires little or no effort (concerning the use of devices,
different software or configurations).</p>
      <p>Here, we claim that the use of Cloud services (especially
in a way presented in the architecture above), is a means to
gain high scalability and interoperability, not only between
hardware devices, operating system and software
applications, but in particular between educational scenarios.
From the point of view of cloud services in educational
scenarios, which we are presenting in this article, cloud
services are regarded as being advantageous in the context of
this section, as they denote a very high accessibility in terms
of time, devices, and platforms.</p>
      <p>OUTLOOK AND FUTURE WORK</p>
      <p>The presented approach for the integration of Cloud
Services into educational scenarios will in the future be used
for the implementation of more flexible learning scenarios in
which students can participate independent from time and
location and by using their favorite communication channel.</p>
      <p>Informal learning scenarios can particularly benefit from
this kind of participation, as it allows for an easier
contextualization of the learner, which is still a hot topic, in
mobile learning scenarios for example.</p>
      <p>Furthermore, this research allows empirical
investigations in areas such as ease of use and usefulness of
mobile devices in educational contexts, of relations between
user traits and technology usage, or in uncovering usage
patterns in this innovative field of computer-supported
education. Also, the use of such services increases the
possibilities for integrating analysis and context-awareness
mechanisms, e.g., by using social network analysis or
educational data mining techniques.</p>
    </sec>
  </body>
  <back>
    <ref-list>
      <ref id="ref1">
        <mixed-citation>
          [1]
          <string-name>
            <given-names>D.</given-names>
            <surname>Chappell</surname>
          </string-name>
          (
          <year>2008</year>
          ).
          <article-title>A short introduction to cloud platforms: An enterprise oriented view</article-title>
          . San Francisco, CA: Chappell and Associates.
        </mixed-citation>
      </ref>
      <ref id="ref2">
        <mixed-citation>
          [2]
          <string-name>
            <given-names>M.</given-names>
            <surname>Jansen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>L.</given-names>
            <surname>Bollen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Schäfer</surname>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Integrating social networking sites in day-to-day learning scenarios - a Facebook-based approach</article-title>
          .
          <source>In Proceedings of the International Conference on Education &amp; E-Learning Innovations (ICEELI</source>
          <year>2012</year>
          ).
        </mixed-citation>
      </ref>
      <ref id="ref3">
        <mixed-citation>
          [3]
          <string-name>
            <given-names>O.</given-names>
            <surname>Pettersson</surname>
          </string-name>
          ,
          <string-name>
            <given-names>B.</given-names>
            <surname>Vogel</surname>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Reusability and Interoperability in Mobile Learning: A Study of Current Practices</article-title>
          .
          <source>In Proceedings of WMUTE</source>
          <year>2012</year>
          (
          <article-title>IEEE International Conf</article-title>
          . on Wireless, Mobile and Ubiquitous Technologies in Education, Takamatsu, Japan).
        </mixed-citation>
      </ref>
      <ref id="ref4">
        <mixed-citation>
          [4]
          <string-name>
            <given-names>L.</given-names>
            <surname>Bollen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>M.</given-names>
            <surname>Jansen</surname>
          </string-name>
          ,
          <string-name>
            <given-names>S. C.</given-names>
            <surname>Eimler</surname>
          </string-name>
          .
          <article-title>Towards a multichannel input dimension in learning scenarios with mobile devices</article-title>
          .
          <source>In Proceedings of WMUTE</source>
          <year>2012</year>
          (
          <article-title>IEEE International Conf</article-title>
          . on Wireless, Mobile and Ubiquitous Technologies in Education, Takamatsu, Japan).
        </mixed-citation>
      </ref>
      <ref id="ref5">
        <mixed-citation>
          [5]
          <string-name>
            <given-names>T. A.</given-names>
            <surname>Angelo &amp; P. K. Cross</surname>
          </string-name>
          (
          <year>1993</year>
          ).
          <article-title>Classroom Assessment Techniques</article-title>
          , 2nd ed. San Francisco: Jossey-Bass.
        </mixed-citation>
      </ref>
      <ref id="ref6">
        <mixed-citation>
          [6]
          <string-name>
            <given-names>J. F.</given-names>
            <surname>Chizmar</surname>
          </string-name>
          &amp;
          <string-name>
            <surname>A. L. Ostrosky</surname>
          </string-name>
          (
          <year>1998</year>
          ).
          <article-title>The one-minute paper: some empirical findings</article-title>
          .
          <source>Journal of Economic Education</source>
          , vol.
          <volume>29</volume>
          , pp.
          <fpage>3</fpage>
          -
          <lpage>10</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref7">
        <mixed-citation>
          [7]
          <string-name>
            <given-names>D. R.</given-names>
            <surname>Stead</surname>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>A review of the one-minute paper</article-title>
          .
          <source>Active Learning in Higher Education</source>
          , vol.
          <volume>6</volume>
          , pp.
          <fpage>118</fpage>
          -
          <lpage>131</lpage>
          .
        </mixed-citation>
      </ref>
      <ref id="ref8">
        <mixed-citation>
          [8]
          <string-name>
            <given-names>G.</given-names>
            <surname>Light and R. Cox</surname>
          </string-name>
          (
          <year>2001</year>
          ).
          <article-title>Learning and Teaching in Higher Education</article-title>
          . London: Paul Chapman Publishing.
        </mixed-citation>
      </ref>
      <ref id="ref9">
        <mixed-citation>
          [9]
          <string-name>
            <given-names>A.</given-names>
            <surname>Giemza</surname>
          </string-name>
          ,
          <string-name>
            <given-names>P.</given-names>
            <surname>Verheyen &amp; H.U. Hoppe</surname>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Challenges in scaling mobile learning applications: the example of quizzer</article-title>
          .
          <source>In Proceedings of WMUTE</source>
          <year>2012</year>
          (
          <article-title>IEEE International Conf</article-title>
          . on Wireless, Mobile and Ubiquitous Technologies in Education, Takamatsu, Japan).
        </mixed-citation>
      </ref>
      <ref id="ref10">
        <mixed-citation>
          [10]
          <string-name>
            <surname>Bollen</surname>
            ,
            <given-names>L.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Eimler</surname>
            ,
            <given-names>S.</given-names>
          </string-name>
          ,
          <string-name>
            <surname>Jansen</surname>
            ,
            <given-names>M.</given-names>
          </string-name>
          , &amp;
          <string-name>
            <surname>Engler</surname>
            ,
            <given-names>J.</given-names>
          </string-name>
          (
          <year>2012</year>
          ).
          <article-title>Enabling and evaluating mobile learning scenarios with multiple input channels</article-title>
          .
          <source>In Proceedings of CRIWG 2012 (18th CRIWG Conference on Collaboration and Technology</source>
          , Raesfeld, Germany).
        </mixed-citation>
      </ref>
      <ref id="ref11">
        <mixed-citation>
          [11]
          <string-name>
            <surname>C.-C. Liu</surname>
          </string-name>
          &amp; L.
          <string-name>
            <surname>-C. Kao</surname>
          </string-name>
          (
          <year>2005</year>
          ).
          <article-title>Handheld devices with large shared display groupware: tools to facilitate group communication in one-toone collaborative learning activities</article-title>
          .
          <source>In Proceedings of WMTE</source>
          <year>2005</year>
          (IEEE International Workshop in Wireless and Mobile Technologies in Education, Tokushima, Japan).
        </mixed-citation>
      </ref>
      <ref id="ref12">
        <mixed-citation>
          [12]
          <string-name>
            <given-names>L.</given-names>
            <surname>Bollen</surname>
          </string-name>
          , G. Juarez,
          <string-name>
            <given-names>M.</given-names>
            <surname>Westermann &amp; H. U. Hoppe</surname>
          </string-name>
          (
          <year>2006</year>
          ).
          <article-title>PDAs as input devices in brainstorming and creative discussions</article-title>
          .
          <source>In Proceedings of WMUTE</source>
          <year>2006</year>
          (IEEE Workshop on Wireless, Mobile and Ubiquitous Technologies in Education, Athens, Greece).
        </mixed-citation>
      </ref>
    </ref-list>
  </back>
</article>