=Paper=
{{Paper
|id=None
|storemode=property
|title=A Global Process for Using Model-Driven Approaches in User Interface Design
|pdfUrl=https://ceur-ws.org/Vol-617/MDDAUI2010_Paper09.pdf
|volume=Vol-617
}}
==A Global Process for Using Model-Driven Approaches in User Interface Design==
https://ceur-ws.org/Vol-617/MDDAUI2010_Paper09.pdf
A global process for using
model-driven approaches in user interface design
Sybille Caffiau, Patrick Girard
LISI / ENSMA
Site du Futurosope – Téléport 2
86961 Futuroscop Chasseneuil Cédex – France
{caffiaus, girard}@ensma.fr
ABSTRACT • All considered research issues are concerned with
In user interface design, model-driven approaches usually classical WIMP1 applications. The hierarchical
use a generative solution, which has obvious limitations, structure of task models is used to build the interface
especially for advanced user interfaces. Based on strong navigation scheme. We demonstrated in [4] that
associations between task models and dialogue models, introducing non menu-based interactions implies a non-
we propose a global process, which facilitates the design automatic transformation of the dialogue.
of interactive applications conform to their models, with
• Generating is not easy to include in iterative design
the including of a rule-checking step. This process permits
cycles such as HCI-adapted cycles. When changes are
either to start from a task model or a user-defined
required, it is necessary to modify the high-level
prototype. In any case, it allows an iterative development,
models, and to generate again a new skeleton, to be
in line with user-centered design standards.
improved again by hand-made add-ons. Some results
have been obtained around the definition of “round-trip
Author Keywords
engineering” [6, 7], but were not applied to HCI. More,
Task Model, Dialogue Model, Metamodel, Design
this approach prevents the designers from starting from
Method, Model-Driven Approach.
the prototype, which method is often used in post-
WIMP design.
ACM Classification Keywords
H5.2 [Information Interfaces and Presentation]: User Our aim is to introduce a new way to use models in user
Interfaces, User-centered design; H.1.2 [Models and interface design. Leaning on meta-models of one task
Principles]: User/Machine Systems. model and one dialogue model, we wrote equivalence
rules between such models. Then, we defined a new
INTRODUCTION development cycle that can be used in a user-centered
Model-driven approaches have been promoted for years. iterative approach.
Despite their great interest, they remain hard to use in the
In this paper, the context of the used models is first
context of user-centered design, especially when novel
described. Then, an example of the meta-models is given,
interaction techniques are expected. Thus, several
and equivalence rules are presented. In the third part, the
research works [1-3] used a generative approach to build
proposed way to use these models in a development cycle
user interfaces – mainly skeletons to be completed – from
is outlined.
task models. Following the analysis we made in [4], we
can argue that this approach has several limitations:
CONTEXT OF THE STUDY: THE MODELS
• Generating requires the addition of information in order The starting point of our work is the analysis from [4].
to reach an operative stage of interfaces. This Whilst the generation appears to be too limitative, links
information can be added to high-level models, which between task models and user interfaces seem obvious.
then loose their original goal; so doing they become So, we decided to explore the possibility to establish
hard to understand and to use, because of their multiple strong links between task model and other models, and to
semantics (for example, adding presentation consider exploiting said links in software design methods.
information to task models results in adding new For some reasons, which are external to our subject here,
semantics to this model). The other way is to insert this we chose the K-MAD model [8] as our task model.
information during the generating process. This second
In our laboratory, we have been working for some time on
approach is for example used in TERESA [5] by the
dialogue models and formal approaches in HCI. We
way of heuristics, which are applied during the process.
introduced a software architecture model, H4, which was
This however results in a lack of understanding of such
transformations by users.
1
Windows, Icons, Menus and Pointers
Pre-proceedings of the 5th International Workshop on Model Driven Development of Advanced User Interfaces (MDDAUI 2010): Bridging between User Experience and UI
Engineering, organized at the 28th ACM Conference on Human Factors in Computing Systems (CHI 2010), Atlanta, Georgia, USA, April 10, 2010.
Copyright © 2010 for the individual papers by the papers' authors. Copying permitted for private and academic purposes. Re-publication of material from this volume requires
permission by the copyright owners. This volume is published by its editors.
33
first dedicated to computer-aided systems. Coupled with transitions. This allows to consider the dialogue at the
that architectural model, we proposed a dialogue model, level of abstract level one wants. This is particularly
the hierarchical interactors [9], and developed tools to important when post-WIMP interaction techniques are
apply it [10]. Because of its hierarchical structure, the used.
Hierarchical Interactor (HI) model appeared as
the most suitable for our purpose. A previous
study demonstrated the capacity to exploit these
two models (K-MAD and HI) in HCI design
[11].
Then, we defined the meta-model of these two
models, which is published in [12]. We chose to
use the EXPRESS language, an alternative to the
OMG approach for meta-modeling. EXPRESS is
a standard data modeling language for product
data. It is formalized in the ISO Standard for the
Exchange of Product model STEP (ISO 10303),
and standardized as ISO 10303-112. It is
supported by complete verification tools, and
allows a full expression of constraints [13].
PRINCIPLES
In this section, we give a short description of the
K-MAD and HI models, and provide some
examples of the meta-models.
The K-MAD model
The K-MAD model is a hierarchical model
where tasks are decomposed in sub-tasks, with
temporal operators describing the dynamics of the model. Figure 1: EXPRESS definition of the Task entity (partial)
The description can be enhanced by the definition of
objects and expressions (preconditions, post-conditions, Such as in advanced state machines, transitions may be
and actions) to control the model dynamics more guarded by expressions, which involve variables. They
precisely. The semantics of these different elements is also can trigger actions. Figure 2 (next page) illustrates a
defined in details. transition meta-model.
Associations between models
Figure 1 illustrates a sample of the EXPRESS definition
The general philosophy of our approach is to take
of the central element of the model, the task.
advantage of the hierarchical nature of the two models to
establish strong associations between them.
The Hierarchical Interactor (HI) model
The HI model consists in a state machine model where the
The task/transition association
dialogue of the application is split into independent
The first obvious association can be made between tasks
automata. Transitions are activated by tokens that
from the task model and transitions from the dialogue
represent user inputs or automaton productions.
model. This link has been largely used in the previous
The hierarchical organization of the model allows the research works, but for us, the link is not a bijective link:
automata to produce and consume tokens. The main because of the need for interaction facilities in
advantages of this system are two-fold: applications, there can be more transitions than user tasks.
• Automata are independent from each other. They can be
The compound-task/automaton association
removed or added independently, without any change to The structure of the dialogue model encourages
others. considering each task decomposition as equivalent to a
• Tokens are the key elements of the model. As they can specific automaton. The structure of the automaton must
refer to both user entries and automaton productions, then be compatible with the dynamics described through
they break the binding between user inputs and the temporal operator of the compound task. Again, the
dialogue may be richer than the simple translation of the
2 temporal operator. Another consequence of this
http://www.tc184-sc4.org/
association is the equivalence between tokens and
34
compound tasks: each compound task may be achieved by dialogue, or they can be used in verification to state that
the way of an automaton that produces a token that stands two models are compatible. In that way, our work might
for the task achievement. be compared to [14]. We describe in the next section the
different usages of this duality.
THE GLOBAL PROCESS
In this section, we describe the global
process we propose to utilize the model-
driven approach we describe above.
As previously claimed in the
introduction, generating dialogue model
from task models suffers from
drawbacks; the most important of them
is related to the iterative nature of user-
centered approaches. When changes
must be made in response to new or
enhanced user needs, the generating
process must be run again, and all hand-
made changes in the interface are lost.
We argue that, if a generation phase
occurs, it must be restricted to a starting
point; then, the process must be able to
achieve without any further generation.
The scenario schema we propose is as
follows.
Assuming we are able to design, edit
and verify each of both task and
dialogue model. Each of these phases
will be called “X-editing phase”
Figure 2: EXPRESS definition of the Transition entity thereafter. These phases may be realized independently
from each other. Our model-driven approach consists in
The object/variable and expression associations including these phases in a dynamic design process.
Both task model and dialogue model use expressions,
which manipulate objects/variables. This link is patent, Optionally, one can start by a “task-editing phase”, from
but was not described in the previous works because the which a starting skeleton for the dialogue model can be
used task model did not formally consider objects and derived (e.g. generated, but only once). Either kinds of
expressions. rules, existence rules and semantic rules, can be used to
produce this skeleton. Then, the next phase consists in
Rules between models filling in the skeleton, in a “dialogue-editing phase”.
Two kinds of rules can be established between the models Adding specific dialogue elements, the dialogue model
[12], based on the previously defined associations. can be completed.
The first kind of rules concerns the existence of logically During this step, the two models can be confronted for
associated entities in both models. For example, are there detecting inconsistencies. By adding specific interaction
one token and one automaton for each compound task? Or elements to the skeleton, the designer might have changed
is there one transition in the dialogue model for each task the semantics of the model.
in the task model? To reach this objective, the designer must associate the
The second kind of rules relates to the semantics of the two models: some added dialogue entities might be
models. Are the semantics of the expressions we can find related to task entities.
in each model equivalent? Is the navigation, which is After analysis, depending on the result, different solutions
allowed by the automata, consistent with the temporal can be applied:
decomposition of the tasks?
• Fail. The two models do not match. Some tasks are
These rules can be exploited in two ways. They can be missing in the dialogue model. The dialogue model
used in initial design to generate a skeleton of the
35
must be improved to take into account the whole task 3. Wolff, A. and P. Forbrig. Deriving User Interfaces
model. from Task Models. in MDDAUI'09. 2009. Sanibel
• Fail. The two models do not match. The dynamics of Island, USA: CEUR-WS. p. 4.
the two models differ. The task model and/or the 4. Caffiau, S., et al. Generating Interactive Applications
dialogue model must be modified. from Task Models: a Hard Challenge. in TAsk
MOdels and DIAgrams (TAMODIA). 2007. Toulouse,
• Success. The two models match. The system is now France: Springer Berlin/Heidelberg. p. 267-272.
ready to being tested by users. 5. Berti, S., et al. TERESA: a transformation-based
A user evaluation phase may result in new requirements, environment for designing and development multi-
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Figure 3 is a Petri net diagram that represents the global
6. Hettel, T., M. Lawley, and K. Raymond. Model
process. The process can start either from the Dialog-
Synchronisation: Definitions for Round-Trip
Editing Phase or the Task-Editing Phase. After rule
Engineering. in Theory and Practice of Model
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Switzerland: Springer. p. 31-45.
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7. Sendall, S. and J. Küster, Taming Model Round-Trip
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Figure 3: The global process. 2009, Springer: Berlin. p. 664-673.
CONCLUSION 12. Caffiau, S., Approche dirigée par les modèles pour la
In this paper, we present a global process to use a model- conception et la validation des applications
driven approach in user interface design. This process interactives : une démarche basée sur la modélisation
uses rules that allow to check the validity of task models des tâches, in LIIS/ENSMA. 2009, Poitiers: Poitiers.
and dialogue models. Moreover, this process is compliant p. 240.
to user-centered approaches that promote iterative design. 13. Dehainsala, H., et al. Ingénierie dirigée par lesmodèles
en EXPRESS : un exemple d’application. in IDM.
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