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carried out by the e-learning providers who act as produsers. Teachers, creating new
learning objects in collaboration with the rest of users, have to produce educational
material in accordance with the usability factors of our model, with particular care
of the accessibility issues for ensuring access also by users with special needs.
13.6 Conclusions and Future Work
In this chapter, we addressed the issue of developing collaborative e-learning
systems that are accessible and usable by users with different profiles (including
those with special needs). We started with the presentation of the assistive tools that
can help to access and insert educational materials in collaborative e-learning
systems. Then, an overview of current usability models for interactive systems
has been presented along with the accessibility guidelines developed by the W3C.
The experience gained during the development of VisualPedia, a collaborative
environment in which users with different abilities can cooperate to create, share,
transfer, and use learning objects, has been reported. This system has been con-
ceived by adopting a life-cycle model based on an iterative usability evaluation
process. According to this model, VisualPedia has been evaluated in its initial
prototyping phase by means of heuristic analysis and experiments with end users.
These evaluations highlighted some usability problems but also a high acceptance
by users with disabilities.
Further steps are required to improve the accessibility and the usability of
VisualPedia, and therefore a usability model has been defined starting from studies
on accessibility and usability carried out by several research institutions, interna-
tional organizations, or national governments. This model stems from the QUIM
consolidated model and extends it for considering properties related to collabora-
tion and specific accessibility facets contained in the W3C guidelines. This model
can be used in the design process of collaborative environments to evaluate
usability and accessibility facets from different points of view with particular
emphasis on communication and accessibility factors.
As future work, we plan to design and develop a new version of the VisualPedia
system by addressing the usability issues arising from the heuristic evaluation
presented in this chapter and exploiting the proposed usability model. Moreover,
we wish to develop an articulated set of metrics for the evaluation of the suggested
usability factors, metrics that can be personalized with respect to the specific
contexts of use (user profiles and fruition media). These metrics will be integrated
in a Web application for the quantitative evaluation of usability and accessibility of
collaborative systems. Finally, we wish to better investigate the connection between
usability and W3C accessibility guidelines in order to enhance the proposed
usability model.
Acknowledgment This work has been partially supported by a grant from “Ministero della
Pubblica Istruzione” within the project “Nuove Tecnologie e Disabilit`. Azione 6: Progetti di
ricerca per l'innovazione”.
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