making method for combining evidence from two
different modes in order to identify the users’
emotions. More specifically, the Simple Additive
Weighting (SAW) (Fishburn 1967, Hwang & Yoon
1981) has been applied in the educational user
interface for evaluating different emotions, taking
into account the input of the two different modes and
selecting the one that seems more likely to have
been felt by the user. In this respect, emotion
recognition is based on several criteria that a human
tutor would have used in order to perform emotion
recognition of his/her students during the teaching
course.
A main difference of the proposed approach with
other systems that employ decision making theories
(Naumann 1998; Schütz & Schäfer 2001;
Bohnenberger et al. 2005; Kudenko et al. 2003) is
that the values of the weights of the criteria are not
static. More specifically, the values of the criteria
used in the proposed approach are acquired by user
stereotypes and differ for the different categories of
users. Stereotypes constitute a common user
modelling technique for drawing assumptions about
users belonging to different groups (Rich 1989;
1999). In our case, user stereotypes have been
constructed with respect to the different emotional
states of users that are likely to occur in typical
situations during the educational process and their
interaction with the educational software and
represent the weight of the criteria.
The main body of this paper is organized as
follows: In section 2 we present and discuss the
MBIUI life-cycle framework. In sections 3 and 4 we
present briefly the experimental studies for
requirements capture and analysis. Section 5
describes the design of the affective bi-modal
educational application and section 6 its main
characteristics. In section 7 we present and discuss
the results of the evaluation of the multi-criteria
model. Finally, in section 8 we give the conclusions
drawn from this work.
2 MBIUI LIFE-CYCLE
FRAMEWORK
MBIUI life-cycle framework is based on RUP,
which gives a framework of a software life-cycle
that is based on iterations and maintains its phases
and procedural steps. However, RUP does neither
specify what sort of requirements analysis has to
take place nor what kind of prototype has to be
produced during each phase or procedural step. Such
specifications are provided by our MBIUI
framework concerning IUIs that are based on multi-
criteria theories.
According to MBIUI framework, during the
inception phase, the requirements capture is
conducted. During requirements capture, a prototype
is developed and the main requirements of the user
interface are specified. At this point the multi-
criteria decision making theory that seems most
promising for the particular application has to be
selected. This decision may be revised in the
procedural step of requirements capture in the phase
of construction.
According to MBIUI, in the inception phase,
during analysis, two different experiments are
conducted in order to select the criteria that are used
in the reasoning process of the human advisors as
well as their weights of importance. The
experiments should be carefully designed, since the
kind of participants as well as the methods selected
could eventually affect the whole design of the IUI.
Both experiments involve human experts in the
domain being reviewed.
The information collected during the two
experiments of the empirical study is further used
during the design phase of the system, where the
decision making theory that has been selected is
applied to the user interface. More specifically, in
the elaboration phase, during design, the user
modelling component of the system is designed and
the decision making model is adapted for the
purposes of the particular domain. Kass and Finin
(1989) define the user model as the knowledge
source of a system that contains hypotheses
concerning the user that may be important in terms
of the interactive behaviour of the system.
In the elaboration phase, during implementation,
the user modelling component of the system as well
as the basic decision making mechanisms are
developed. As a result a new version of the IUI is
developed which incorporates fully the multi criteria
decision making theory.
In the construction phase, during testing, the IUI
that incorporates the multi-criteria decision making
theory is evaluated. The evaluation of IUIs is very
important for their accuracy, efficiency and
usefulness. In MBIUI, evaluation is considered
important for two reasons: 1) the effectiveness of the
particular decision making theory that has been used
has to be evaluated 2) the effectiveness of the IUI in
general has to be evaluated. In case the version of
the IUI that incorporates a particular decision
making theory does not render satisfactory
evaluation results with respect to real users and
human experts, then the designers have to return to
requirements capture, select an alternative decision
making model and a new iteration of the life cycle
takes place. In transition phase, during testing, the
decision making model that has been finally selected
USING MBIUI LIFE-CYCLE FRAMEWORK FOR AN AFFECTIVE BI-MODAL USER INTERFACE
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