A System to Support Asynchronous Collaborative Learning
Tasks Using PDAs
Ana I. Molina
(Escuela Superior de Informática, Castilla - La Mancha University,
Miguel A. Redondo
(Escuela Superior de Informática, Castilla - La Mancha University,
(Escuela Superior de Informática, Castilla - La Mancha University,
Abstract: Some tasks supported by educative and collaborative
tools can be more realistic and accessible if they are tackled using mobile
devices. This approach allows students to benefit from the mobility features
of this kind of devices, which are expected to revolutionize teaching in
the next decade. In this paper we present an application called DomoSim-Mob
to carry out practical activities of domotical design using PDAs. We introduce
the task of collaborative planning of design which is supported by DomoSim-Mob
and describe its materialization starting from the user tasks supported
by the previous desktop computer version.
Keywords: PDA, Computer-Supported Collaborative Learning, mobile
There are numerous applications based on the use of computers, which
help people solve tasks faster and more easily than before. Their use has
been introduced into many different areas and in addition, the hardware
supporting these tasks is becoming more and more powerful and versatile
[Sharples, 00]. Unfortunately, this is not the case
as regards the use of Information Technologies in educational environments,
where the introduction of these devices is still slow and the real possibilities
of mobility are not exploited (for example, learning at anytime and anywhere).
We believe that the educational environment can be enriched with certain
elements that improve the learning process. Among these new devices we
should point out PDAs (Personal Digital Assistants). We advocate the introduction
of the ubiquitous computing paradigm in the classroom for educational purposes
and will take a look at some of the educational benefits its use would
We have taken as a starting point a collaborative e-learning environment
based on desktop metaphor [Shneiderman, 97] and
we have studied some tasks that could be improved through the use of mobile
devices like PDAs. For this purpose we have developed an extension of the
Domosim-TPC desktop system called Domosim-MOB.
In this paper, we will focus the discussion on describing the functionality
of Domosim-MOB from the user's point of view and we will point out some
issues regarding its development and implementation.
The paper is organized in the following way: section
2 introduces the learning situation and section 3
describes the task of collaborative learning; In section
4 the DomoSim-Mob environment is explained; and section
5 looks at some aspects of design and implementation. Finally we will
draw some conclusions and outline the future work we
are planning to develop.
2 Learning situation and previous work
The domain where the necessity appeared and where our investigation
is being applied is the learning of Domotics, i.e., the design of automated
control facilities in buildings and housing. The term Domotics is associated
with the set of elements that, when installed, interconnected and automatically
controlled at home, release the user from the routine of intervening in
everyday actions and, at the same time, provide optimized control over
comfort, energy consumption, security and communications. In Spain the
Formación Profesional (Technical Training) defined in the LOGSE
(Spanish Law for Primary and Secondary Education) takes professional profiles
into account where training in Domotics is considered as a necessity. Some
learning stages in electrical engineering and electronic courses are centered
on the study of the design and maintenance of singular installations and
the automation of buildings dedicated to housing. In this area the design
of domotical installations has a fundamental role. In this kind of training,
the performance of practical experiments is particularly important. Practical
activities in laboratories are performed by several students sharing a
panel on which domotic elements are located with the aim of testing a proposed
design. However, the material needed to carry out these experiments is
usually expensive and in many cases not easily available. In order to alleviate
this problem by means of the use of technology, we have developed a distributed
environment with support for distance learning of domotics design: DomoSim-TPC
In DomoSim-TPC the teacher carries out a presentation of the theoretical
contents. Next, the students are organized into small groups to whom the
teacher assigns the resolution of design problems. The students use an
individual workspace to design the models that they consider will satisfy
the requirements of the proposed problems. Later on, they discuss, comment
and justify the design decisions taken, thus building a shared knowledge
base. This system follows Abstract Assisted Interaction [Bravo,
01] and Direct Manipulation paradigms and is based on the desktop metaphor.
However, some tasks in this tool can be more realistic and accessible
if they are tackled using features of ubiquitous computing. In particular,
we have developed the asynchronous tools in Domosim-TPC. These are the
elements dedicated to the collaborative planning of design. The result
of this evolution is the tool presented here, named Domosim-Mob, which
is a PDA-based application supporting mobile learning.
PDAs (Personal Digital Assistants) are beginning to achieve greater
penetration in the current market of mobile devices. Application of this
kind of devices in face-to-face and/or traditional education is not a novel
Previous publications [Leibiger, 01] [Waycott,
02] show the importance of these devices in the learning process. Among
the limitations found in using these devices in educational environments
we should point out the following: limited memory capacity, possible data
loss, small-size screens, and data entry methods that are new for the user
(tactile keyboard, handwriting recognition). Mobile devices are designed
to be compact and light; but these features lead to certain limitations
as to user interaction. These limitations must be taken into account when
designing and creating applications for supporting learning environments,
as well as for elaborating teaching contents to be visualized.
3 The task of Collaborative Planning of Design
As we have previously pointed out, the teachers propose the carrying
out of problem solving activities. An activity is a mechanism that allows
them to propose a problem for a group of students to solve. In DomoSim-TPC
model, the activities of domotical design learning are structured in two
differentiated phases: (1) Collaborative Planning of Design, and (2) Design
and Simulation. In the first phase in the solution of a problem, the students
reflect on the elements that will be part of the solution and plan the
general actions that they should carry out to build it. In the second phase,
they execute the plan, refining the design and defining the properties
of the elements of the solution [Bravo, 05a]. Once
the design has been materialized, they verify its behavior by means of
simulation [Bravo, 05b].
We use the concept of Collaborative Planning of Design [Redondo,
02] to model activities of the learning of design strategies. These
strategies are sequences of design actions that should be carried out to
build an installation model that satisfies a specification defined in a
problem. This design phase is structured in two concurrent stages: (i)
individual construction of design proposals, and (ii) discussion of the
proposals among the group members.
In the individual construction of a design, the learners individually
reflect on, plan and then define the steps that determine the strategy
to follow in order to build the model that satisfies the requirements specified
in the problem formulation. That is to say, they define the solution and
the way to reach it. When a proposal has been built, it must be presented
to the group in order to be discussed. In the discussion and justification
of the proposals two cognitive practices are developed: designing and collaborating.
The participants discuss the solution asynchronously, its form and the
steps to be taken in order to reach it. By so doing a proposal will be
obtained at this stage through agreement, reflecting the viewpoint of each
participant. This proposal is the plan to be developed in the following
phase of the learning model we propose.
The tasks that the students carry out in the Collaborative Planning
of Design are more reflexive, while the tasks in the second phase are more
spontaneous and interactive. We believe that a greater engagement from
the students could be achieved if we provide support so that these tasks
can be carried out using mobile devices. With this in mind, we have developed
an extension of the desktop system allowing the Collaborative Planning
of the Design tasks using PDAs. This development is derived directly from
the system based on the desktop metaphor [Molina, 04].
4 DomoSim-Mob: A PDA-Based application for domotical
As a result of the aforementioned reasons we have developed Domosim-Mob,
a telematic environment for the collaborative learning/teaching of domotical
design using PDA devices. This tool supports the carrying out of problem
resolution activities in groups by means of distributed planning of proposed
It is important to point out that the functionality supported in PDA
devices is a supplement of the original system. Domosim-Mob is an extension
developed to add mobility to the learning process ("learning anywhere
and at anytime"). Whilst mobility in learning processes favors the
involvement of students in the task in question, the use of these devices
does, however, mean paying the price of visualization limitations.
The tasks supported in Domosim-Mob are similar to Domosim-TPC tasks,
but the access to them has been improved, as a consequence of there being
greater flexibility. Nevertheless, besides the features characteristic
of the discussion process, using mobile devices creates additional problems
due to the fact that it offers the possibility of participating in the
discussion without the need for the device to be connected to the server:
the synchronization with the rest of the members in the group. One-to-one
synchronization, in other words, synchronization of a mobile device with
the system, is quite well resolved. However, in our case a synchronization
of order n to m is necessary. Our approach to solving the problem is by
applying a variation of the Schiper-Eggli-Sandoz algorithm [Aguilar,
05] for the exchange and ordering of messages in distributed systems
respecting a causal order based on a model of logic clocks.
4.1 Description of the DomoSim-Mob application
Domosim-Mob users can access the planning tool once they have been sent
through an authentication process, in which the system recovers the user
profile information. The next step is the selection of a work mode. This
is explained in detail in the section dedicated to the system architecture.
Once a work mode has been selected, the user can access the main interface
of the tool.
4.1.1 The tool for elaborating design plans
Elaborating design plans is an individual task, in which synchronization
with the rest of the group members is not necessary. To carry out this
task it is not necessary to be connected to any kind of system. In other
words, it can be performed by means of a stand-alone mobile device, provided
the necessary information has been transferred to the device to carry out
the task. While the plan is being elaborated, the mobile device records
the data about the plan created by the user and about the way in which
it is created. These data are transferred to the main system when a synchronization
session is established. (a) (b) (c)
Figure 1: User interface of the tool for elaborate design
Figure 1 shows the user interface of the tool for elaborating design
plans. Each problem to be solved (whose statement is shown in figure 1a)
is structured in several sections (these are the tasks which give structure
to the problem).
The users must construct solutions (the design plans) for each of them
(see figure 1b). The list of tasks to carry out appears at the bottom of
the interface. For each task, the sequence of already planned design actions
appears in the center. At the bottom of the screen two buttons are shown.
These allow design actions to be added to and removed from the plan. To
create and add a new design action the user must click on the button labeled
The Dialog box in figure 1c allows a new action
to be constructed using several toolbars. In general, a design action
has four components: the kind of action, the management area, the
housing plan and the domotical operator.
4.1.2 Discussion and argumentation workspace
The discussion workspace (figure 2) is used for
the semi-structured discussion and argument. This discussion model is inspired
by the Topic-based Conversation related to the tasks that the learners
have to solve to build a certain design model [Redondo,
02]. Thus, the discussion process is characterized as a social task
in which the participants in an activity reflect on the work that they
carry out. They collaborate, exchange ideas, propose resolution mechanisms,
argue, justify, refine their contributions and acquire new knowledge, always
in the context of a specific topic. This is called Argumentative Discussion.
In this workspace the contributions posted by the participants in an
activity are organized in a hierarchical way (by means of a tree). This
way, the participants will be able to give and link opinions on one aspect,
argue about a proposal and consult the opinions given by the other members
of the group. In DomoSim-Mob, a contribution is any element characteristic
of the semi-structured discussion mechanism established for the activity.
The submission and the type of a contribution depend on the hierarchical
organization and the role associated to the author.
The system presents a careful organization and representation of the
contributions, making use of a tree-shaped hierarchical organization, where
the root is the activity itself outlined by the coordinator of the group.
The first level of the tree consists of as many nodes as sections or epigraphs
derived from the outlined activity. The rest of the nodes represent the
contributions generated from the discussion in search of a solution, always
in agreement with the conversational structure outlined for the activity
of problem solving learning [Savery, 96]. The different
branches of the tree can expand and contract to facilitate the visualization
of the structure of the discussion made by the participants.
Figure 2: User interface of the tool for discussion and argumentation.
4.1.3 The results workspace
Finally, the results workspace (Figure 3) facilitates
the visualization and perception of the parts of the activity that the
group has already developed and agreed on. The participants can observe
the results and solutions obtained during the process, independently of
the discussion and of the development process necessary for their achievement
(this is the main goal of a groupware tool).
In similarity to the discussion space, the results space has a tree-shaped
hierarchical structure, which is used to organize the information in relation
to the results obtained in the activity. At the root of the tree the identification
of the activity itself appears together with its symbolic icon and the
identification of the coordinator of the group who proposed it. In the
following level of the tree the epigraphs or sections that make up the
activity are located.
Figure 3: Results workspace.
By selecting some of the nodes that represent solutions to an epigraph,
the contents of the solutions obtained can be seen by clicking on the button
labeled "Contenidos". A new window appears with three tabs to
access the three visualization modes shown in figure 3
(textual and graphical representations): the textual representation of
the design plan corresponding to the selected task, the graphical representation
of the sequence of design actions and the final design graph with the results
5 Design and implementation aspects
In this section some design and implementation aspects of Domosim-Mob
are looked at: its structure, the work modes it supports and several issues
related to the user interface and its design.
5.1 The DomoSim-Mob structure
The diagram in figure 4 shows the global structure
of the Domosim-Mob application. The new context of use entails the appearance
of several work modes in the application:
- Connected work session (Figure 4-1). The mobile
application accesses the information server, although not at the same time
as other participants in the group. The information associated with the
group process and the history of the group is recorded and filed at a central
location. Information exchange is based on XML files.
- Disconnected work session (off-line) (Figure 4-2),
in which the user works with local information available in the mobile
device. Students can work in isolation. They reflect on and construct the
solution to the problem, which is stored in the PDA.
- Synchronization session (Figure 4-3). This one
appears as a result of the previous work mode. Students send updated information
to the server (individual contributions in the discussion process and their
answer to the proposed problem) with the aim of providing and storing consistent
information about the collaborative experience. The server distributes
this information to the rest of the members of the teams. In order to guarantee
confidentiality when accessing the server, an authentication process is
Figure 4: General Structure of DomoSim-Mob
5.2 Design of the User Interface
To develop the Domosim-Mob application we have opted for dividing the
information to be visualized into several tabs, in order to solve the lack
of space in small devices, such as PDAs. In order to obtain a coherent
division of the functionality through the different dialog boxes, we have
made the design taking into consideration the tasks model of the application.
We have chosen the ConcurTaskTrees notation [Paternò,
97] to represent the conceptual model. Using this allows the position
and relation between elements (controls or widgets) that compose the user
interface to be determined in a more coherent way, as well as helping to
obtain a more user-centered application.
In order to develop the version for PDA, temporary relationships among
the tasks and the domain application objects manipulated to perform them
must be considered. This information allows the creation of the interface
in which both the widgets (user interface objects) that show domain application
objects (internal objects) and the widgets that allow certain actions applicable
to these internal objects to be executed appear together. In addition,
if we are interested in applying a semiautomatic method to obtain the user
interface, this task analysis should be done at a low level. It has to
determine the kind of interaction task (for example, enter text, select
a Boolean value, select a numerical value) and the kind of domain application
objects manipulated by the tasks. This information facilitates the identification
of the visual component (widget) that best aids in the performance of a
particular task, taking target device restrictions into account.
In order to analyze the task in our system we considered several approaches
to task modeling such as GOMS [Card, 83], HTA [Annett,
67] and UAN [Hix, 93]. We have also analyzed other
methods for analyzing and designing groupware tasks. Some examples are
GTA (Groupware Task Analysis) [van der Veer,
00], TKS (Task Knowledge Structure) [Johnson,
03] or CUA (Collaboration Usability Analysis) [Pinelli,
03]. Some notations have been proposed in the field of workflow
systems [Trætteberg, 99; van
der Aalst, 00]. As for the modeling of this kind of systems there are
various notations worthy of mention: CTT, COMO-UML [Garrido,
03] and XUAN [England, 03]. However, we have chosen
CTT notation because this notation supports several important features:
hierarchical logical structures, temporary relationships among tasks, and
cooperative tasks modeling (multi-user cooperation). There is also a tool
for developing CTT models [Mori, 02]. Nevertheless,
CTT does not provide optimal support for specifying collaborative aspects
(cooperation and collaboration are terms that are sometimes used interchangeably,
but cooperation entails division of work, whereas collaboration implies
a coordinated effort to solve the problem without splitting the tasks [Dillenbourg,
95]). This is an important deficiency in this notation. We intend to
extend CTT notation to support representation of collaborative tasks.
To create the Domosim-Mob application we have chosen Visual Studio .NET
[Vigley, 03] as the development platform and C# as
the programming language. Initially the possibility of using Java was considered,
but finally we opted for using .NET mainly due to the inefficiency of Java/Swing
(using Jeode as the virtual machine). Using AWT we did not have sufficiently
Although studying the usability of the developed tool is not the object
of this paper, we are going to look at some issues related to this matter.
We have taken advantage of the lesson learned about the user interface
in Domosim-TPC [Redondo, 05].
Usability has been our primary objective in designing this system. We
have followed the guidelines and goals of interaction design described
in [Preece, 02], such as learnability or efficiency.
Besides the new context of use and the developed user interface permits
a more guided interaction for the student, less cognitive complexity and
In this article we have described our proposal to support a task of
collaborative learning (Collaborative Planning of Design) using PDA devices.
We had previously developed a system based on the desk metaphor that also
supported this task. This has provided valuable experience for understanding
how to structure and implement a tool supporting this learning task. However,
the development of the version for PDA has not been trivial. As a consequence
of the mobility, new ways of working have appeared (synchronized sessions,
off-line sessions, etc.) and the design of the user interface has been
conditioned by the reduced size of the PDA devices.
In the process of development of the user interface we have tried to
apply techniques of user task modeling and automatic code generation, but
we have found important deficiencies for modeling collaborative tasks.
The notations available allow the modeling of cooperative systems but do
not provide an optimal support for specifying really collaborative aspects.
Cooperation and collaboration are terms that are sometimes used interchangeably,
but there are some differences between them. CTT permits the representation
of cooperation, in which a division of work exists. Each actor (user with
an assigned role) is responsible for a portion of the work. Collaboration
is a mutual engagement of participants in a coordinated effort to solve
a problem. Also there are objects that are created and manipulated by many
people. The contribution of each actor to the final object is not well
identified. Due to the aforementioned limitation the incorporation of capacity
for representing collaborative tasks to the CTT notation is a requirement.
Our next step must be to evaluate our proposal in experiments with users.
The evaluation plan that we have designed proposes comparing the data registered
with the desktop computer based tool and those data we will register in
the experiments using PDAs. In so doing we will evaluate the acceptance
of the new version for use with mobile devices, the degree of the students'
engagement with the proposed activities, and above all, the effectiveness
and the efficiency of the new approach for tackling collaborative learning
using mobile devices.
This work has been partially supported by the University of Castilla-La
Mancha, the Junta de Comunidades de Castilla - La Mancha and the Ministerio
de Ciencia y Tecnología in the projects CoPLAN, PBI-02-026 and TIC2002-01387.
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