QoS Adaptation in Multimedia Multicast Conference Applications for
E-Learning Services
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
The evolution of the World Wide Web service has
incorporated new distributed multimedia conference applications,
powering a new generation of e-learning development and allowing
improved interactivity and prohuman relations. Groupware applications
are increasingly representative in the Internet home applications
market, however, 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 a design goal at the application level becomes crucial for groupware
development, enabling QoS productivity 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 video conferences, are in the frontline
to benefit from QoS adaptation. However, not all include adaptive
technology 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 "Multimedia Technologies: Concepts, Methodologies, Tools, and
Applications", IGI Publishing, 2008