Advances in E-learning-Experiences and Methodologies

Swarm-Based Techniques in E-Learning
arcs are only updated when a user goes through
that arc or through a neighbour (those arcs that
lead to the same exercise). When a student finishes
exercise A, positive and negative pheromones are
laid on the last four arcs that she followed. Thus,
the pheromones on those arcs are increased. At
the same time, pheromone values on all the other
arcs that lead to the same exercise are decreased.
This can be seen as competition between arcs,
as those arcs that are used more often will have
high pheromones values, while those that are
seldom used will see that their pheromones level
“evaporate” rapidly.
The work by Valigliani (2005) has shown
several differences between the application of
ant-inspired heuristics to technical problems (like
those referenced in the background section), in
which “ants” are little software agents, and their
application to social problems, in which real people
are used as “ants.”
First, real students are not as altruistic as ants
(either natural or artificial) are: students will not
willfully sacrifice themselves for the good of
the community. In other words, a student does
not expect to be lost in the exercise graph for the
sake of exploration. All students want to learn.
They are not interested in optimizing the results
of the group; they are interested in optimizing
their own results. This is only common sense, but
it means that there are aspects of the ant-colony
optimization heuristics that cannot be used or do
not perform as expected.
Secondly, the process of learning is one that
must be optimized for each learner. The fact that a
pedagogical path is optimized for a group does not
mean that it is optimized for each of its members.
In order to give an additional level of adaptation
at a personal level, personal pheromones are used.
These pheromones are left by each user as the
user traverses the graph, and prevents the user
from repeating the same exercises over and over
again. Personal pheromones are laid by use and
evaporate with natural time. They are a multiplicative
factor in the fitness function.
A final characteristic of the Paraschool system
is its ability to create new arcs that connect its
exercises, apart from those that were set by the
pedagogical team. Paraschool users can navigate
in a guided fashion (as explained above) or freely.
Free navigation means that the students can access
any of the exercises that are available on the
site. Every time this happens, the system records
the transition and creates a new arc from the last
exercise performed by the student to the exercise
that she has gone to. From that point on, that
arc is considered like a normal arc of the graph
(only with no starting pedagogical weight) that is
selectable in normal guided navigation, receive
pheromones, and so forth. This is an interesting
feature that allows finding learning sequences
that the pedagogical team had not thought about
in the first place. Moreover, it opens the door to
new exercises to be added to the system even if
no pedagogical team creates a graph for them. As
connections between the arcs will appear from free
navigation, the algorithm will assign a fitness to
those arcs over time, as pheromones are deposited
on them with regard of success or failure of the
students traversing them. In the end, the new set
of exercises will auto-organize themselves.
Learning networks
Learning networks (Koper, 2005) are flexible
learning facilities oriented at supporting the
needs of learners at various levels of competence
throughout their lives. They support ubiquitous
access to learning facilities at work or at home.
Learning networks consist of learning events
(called activity nodes) in a given domain. Activity
nodes can be associated to anything that supports
learning (e.g., Web resource, course, workshop,
etc.). Both providers and learners can create new
activity nodes or adapt existing ones (even deleting
nodes). Thus, a learning network represents
a large and ever-changing set of activity nodes
that provide learning activities for learners,
from different providers and at different levels
of expertise.
0