Web-based education enables learners and teachers to access a wide quantity of continuously updated educational sources. In order to support the learning process, a system has to provide some fundamental features, such as simple mechanisms for the identification of the collection of “interesting” documents, adequate structures for storing, organizing and visualizing these documents, and appropriate mechanisms for creating personalized adaptive paths and views for learners.
Adaptive Educational Hypermedia seek to apply the personalized possibilities of Adaptive Hypermedia to the domain of education, thereby granting learners a lesson individually tailored to them. A fundamental part of these systems are the concept spaces, i.e., simple and clear visual layouts of concepts and relations among them.
In this paper we propose a new visual layout model in e-learning environments based on the zz-structures, which are graph-centric views capable of representing contextual interconnections among different information. In order to describe the use of these structures, we present their formal analytic description in terms of graph theory, focussing, in particular, on the formal description of two views (H and I views), and on different extensions of these notions to a number n > 2 of dimensions. We then apply all these formal descriptions, and some particular properties of zz-structures, to an example in the Web-based education field.
