Synchronous E-Learning Integrating Multicast Applications and
Adaptive QoS
Sérgio Deusdado1, Paulo Carvalho2
Instituto Politécnico de Bragança1
P-5300 Bragança, Portugal
E-mail: sergiod at ipb.pt
<>Universidade do Minho2
Departamento de Informática
P-4710-057 Braga, Portugal
E-mail: pmc at di.uminho.pt
>
Abstract
A new generation of e-learning development, based on synchronous
groupware applications integration, providing improved interactivity
and pro-human relations, allows richer training experiences far
beyond a virtual classroom. Despite WWW service evolution,
e-conferencing multimedia applications remain “killer applications” and
insensitive to resources degradation, in fact, the quality of service
(QoS) provided by the network is still a limitation impairing their
performance. Such applications have found in multicast technology an
ally contributing for their efficient implementation and scalability.
Additionally, considering QoS as design goal at application level
becomes crucial for groupware development, enabling QoS proactivity to
applications. The applications’ ability to adapt themselves dynamically
according to the resources availability can be considered a quality
factor. Tolerant real-time applications, such as videoconferences, are
in the frontline to benefit from QoS adaptation. However, not all
include adaptive technology is able to provide both end-system and
network quality awareness. Adaptation, in these cases, can be achieved
by introducing a multiplatform middleware layer responsible for
tutoring the applications’ resources (enabling adjudication or
limitation) based on the available processing and networking
capabilities. Congregating these technological contributions, an
adaptive platform has been developed integrating public domain
multicast tools, applied to a Web-based distance learning system. The
system is user-centered (e-student), aiming at good pedagogical
practices and proactive usability for multimedia and network resources.
The services provided, including QoS adapted interactive multimedia
multicast conferences (MMC), are fully integrated and transparent to
end-users. QoS adaptation, when treated systematically in tolerant
real-time applications, denotes advantages in group scalability and QoS
sustainability in heterogeneous and unpredictable environments such as
the Internet.
in
the book "Strategic Applications of Distance Learning Technologies",
IGI Publishing, 2008