and analysing how this is confronted and how to
solve the problem (París, 2007). Taking this into
consideration, a student’s profile would be made up
of two components: (1) a particular component,
which is obtained from the student’s knowledge and
aptitude for a concrete topic; and (2) a general
component, which is the calculation of all the
particular components of the student’s profile.
The rationale behind considering this double
component stems from the fact that the student may
be very able in a concrete topic (as he has been
successful in tests) whereas he lacks knowledge in
other areas. Considering purely the general
component of his profile, his knowledge would be
low and consequently, further tests would not be
difficult. Thus challenges would not increase and he
could become demotivated. In the same way, if the
successful result of a test raises the general
component of his profile considerably, later tests
would be more challenging even when the student
has not shown a high level of competence. Thus, the
general component of a student’s profile measures
his general competence in the subject and the
particular component measures his level of
knowledge and aptitude in each topic. The former is
updated when the student logout the system and its
value is calculated as the average value of all
profiles in each topic. The latter is updated after
answering any test belonging to a given topic. The
score of a test is a linguistic label representing the
number of correct/incorrect questions answered and
the student’s behaviour whilst sitting the test. Table
1 shows how the student’s current profile is updated
by this score.
To obtain an initial student´s profile in each area,
one can consider the mandatory realisation of a
number of non adapted tests. This initial profile
would be constantly modified depending on results
obtained in adapted tests. This type of test would be
set up automatically by selecting questions whose
level of difficulty suits the student’s profile:
depending on his particular level of knowledge and
errors committed when doing previous tests on the
same topic.
3 ARCHITECTURE
To facilitate the evaluation process task, we have
mentioned the use of self-evaluation assessments as
a means of evaluating acquired knowledge and
helping study. In order to be really useful, these
assessments must adapt the difficulty of the
questions to the student’s level of qualification. This
solution has been implemented in a self-evaluation
software tool which can automatically generate a test
and a personalised profile (París, 2007). Due to the
complexity to handle symbolical knowledge, the
possibility to break down the global task into small
sub-tasks, the distributed vision of the problem
solving process over Internet, and the consequent
reduction of development and maintenance costs, we
considered a distributed solution using agent
technology.
Table 1: Updating student’s current profile by a test score.
Current
profile
Score of self-evaluation test
Very
high
High Medium Low
Very
Low
High
High High High Medium Low
Medium
High High Medium Low Low
Low
High Medium Low Low Low
The multi-agent system developed uses a host of
agents to manage the self-evaluation process, from
the moment when the system is accessed, passing
through the process of generating the test, to the
moment when results are given. Figure 1 show the
organization of agents which carry out these tasks.
Figure 1: Organization of the Multi-agent system.
3.1 Description of Agents
The Interface Agents allow the student’s interaction
with the tool. Two types can be distinguished:
Generic Interface Agent, for students who have not
been authenticated, and Student Interface Agent, for
authenticated users.
The Intermediate Agents carry out the tasks
requested through the interface. They are classified
as follows:
Student Agent: maintains the student’s profile
during the interaction with the system. Its
aims are to inform and design the student’s
profile.
Authentication Agent: controls a student’s
access to the tool and ensures he is identified
until he has finished the interaction. When the
Authentication Agent authorises access, a
Student Agent is created.
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