A framework for the multi-disciplinary design of Web-based educational systems

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System architecture

In [2] authors described the application of the MODUWEB approach to integrate two domain specific languages: IMS LD and Labyrinth. IMS LD is a language for describing learning activities and provides the means to describe the roles and the activities carried out by the different participants of a learning process [3]. Labyrinth is a set of notations to specify web and hypermedia applications from an abstract point of view [4]. The web system structure is modeled in Labyrinth by means of a set of nodes which can contain as many information items (contents) as required. Composite nodes can aggregate and generalize other components in order to provide programmers with a clear structural diagram of the application. More information on the meta-model can be found in [4].

The architecture of a system which implements the aforementioned approach is depicted in figure 1. On one hand the system provides client applications for the specification of the different models of a webbased educational system. On the other hand provides the necessary services to transform from one design perspective to another (transformation module), to validate the designs consistency (validation module) and to automatically generate the final application code (generation module). Regarding the client applications provided, in this implementation of the MODUWEB approach the specification of the educational process design is carried out using an IMS LD Visual Editor, while the hypermedia authoring process is supported by the AriadneTool [8].

This toolkit allows the modeling of a hypermedia application, the validation of the hypermedia design, and the dynamic generation of XML + SMIL implementation templates. The AriadneTool environment is based upon the Ariadne Development Method (ADM) [4], which proposes a number of design models (such as Structural Diagram, Navigation Diagram or Authorization Rules) for web design, which are abstractions of the Labyrinth metamodel. The process of creation of a web-based educational system is as follows: the pedagogical expert use the IMS LD visual editor for designing a learning process.

The transformation module will translate the IMS LD design into a set of ADM models annotated with IMS LD information. The web expert can now use AriadneTool to adapt the design in order to produce an application that responds to the requirements of visualization, accessibility and usability specific for that learning process. Prior to the code generation, a validation process will be launched in order to check the compliance of the final design with the IMS LD specification.