other SLNs. The tandem between mobile devices and
cloud computing works perfectly because handheld
terminals are constrained by their processing power,
battery life and storage capabilities, whereas cloud
computing can provide the illusion of unlimited com-
puting resources (Mell and Grance, 2011), (Kim et al.,
2011).
The extra resources required by the handheld de-
vices can be provided either by (i) centralized servers
in the cloud, depending on connectivity to the Inter-
net, or (ii) cloudlets supported by fixed nodes at the
edge of the Internet or by capable mobile terminals
connected in the ad-hoc network. With this in mind,
we take advantage of the concept of Sporadic Cloud
Computing (SCC), presented in (OrdoÃ
´
sez-Morales
et al., 2015), (Ordonez-Morales et al., 2015), in which
the user’s devices exploit both the resources avail-
able in the remaining terminals connected to the ad-
hoc network (computing, storing, networking, sens-
ing,...), and those provided from external data cen-
ters. In our platform, SCC allows to generate vir-
tual and distributed laboratories conformed with ex-
isting resources in the member’s devices of the dif-
ferent SLNs, who are physically close to each other.
This avoids — as far as possible — dependence on
access to the Internet to perform tasks and gives stu-
dents access to specialized software not suitable for
low performance devices. So, our cloud computing
layer provides the following services:
• Storing information in spaces in the cloud, linked
to source/target devices, creating/consuming
users, location, etc.
• Accessing and serving information of high-level
user profiles during the formation of ad-hoc net-
works.
• Synchronizing multiple flows of information
coming from the connected devices.
• Managing of the simulation and programming re-
sources available on the users’ mobile devices so
they can be used in a transparent manner by SLN
members (virtual and distributed laboratories).
• Providing access to cloud services on the Internet:
databases, semantic repositories, physical labora-
tories, etc.
2.3 Knowledge Management Layer
Our platform uses information derived from personal
or institutional sources to provide users with the best
resources (according to their personal learning styles
and characteristics of their access devices) and activ-
ities (both individual and group) that stimulate their
learning and allow them to increase their academic
achievement or satisfy their learning needs. The
"Knowledge Management" layer is the place to put
solutions from the areas of data mining, recommender
systems and the Semantic Web to automatically select
the best profiles to form the learning network, choose
the pieces of information for the greatest benefit of
the members of the SLN, while personalizing the con-
tents delivered by each device and the activities to be
performed by the group. To do this, it is necessary
to rely on techniques for modelling the user’s prefer-
ences, considering different profiles (students, teach-
ers, experts, personal devices...) and contents (insti-
tutional and personal). Moreover, in this modelling
process, OPPIA takes advantage of the academic in-
formation stored in the institutional databases such
as general curriculum (containing several academic
guidelines based on career, skills, course,...), moni-
toring teaching activities, and learning outcomes.
In OPPIA, the contents are modeled through Dy-
namic Reusable Learning Objects (DRLOs) (Valder-
rama et al., 2005), provided by the institution (insti-
tutional DRLOs) or from students, teachers or the In-
ternet. In the same way, we need to use recommen-
dation strategies that select the most appropriate con-
tents for each member or group of members of our
SLNs. In addition, we need modelling techniques to
infer knowledge about the future learning interests of
the SLN members by keeping track their academic ac-
tivities, learner’s web surfing habits and preferences,
and profiles in traditional social networks (obviously,
with the explicit consent from the users). Finally, for
the efficient management of the metadata associated
with the learning process, information storage, analy-
sis and inferences, we need to use learning ontologies,
especially designed for this purpose.
2.4 Expert Systems Layer
To achieve the desired results, both in motivation and
performance of the member of a sporadic learning
network, OPPIA relays selection and design of con-
tents, educational resources, and learning activities to
the "Expert Systems" layer. With this aim, the expert
system incorporates an assembler able to create DR-
LOs. The educational institutions (universities, col-
leges, institutes, schools,...) create official DRLOs
— developed in different formats (video, image, text,
audio,...) to meet the learning styles of students —
that cover the main contents related to the curriculum.
In turn, the DRLO repository can be expanded with
learning objects from users themselves or obtained
from the Internet. Furthermore, OPPIA has the ability
to produce new learning objects and educational re-
sources, from DRLOs existing in the repository. For