Checking the Consistency, Completeness and Usability of Interactive Visual Applications by Means of SR-Action Grammars

The development of interactive visual applications is a complex work, usually performed with the help of advanced visual programming environments. Starting from the GUI’s visual specifications, the programming environment generates the corresponding code that implements the interface. In most cases, designers and developers have no tools to keep control over the usability and the maintainability of the resulting applications. In fact, the success of an information system depends on the accessibility and usability of its interface. The evaluation of visual environments is traditionally performed by means of expert-based evaluations or by testing with end users. In this paper, we describe a methodology to design, specify and evaluate interactive visual applications, based on the SR-Action Grammars formalism. We describe how it is possible to assess the usability metrics of consistency, completeness and user control by means of checks performed at high abstraction level of the visual language. In particular, we improve the formalism of the SR-Action Grammars (Cassino et al. (2003): SR-Task Grammars: A Formal Specification of Human Computer Interaction for Interactive Visual Languages – 2003 Symposium on Visual Languages and Formal Methods (VLFM ‘03) – IEEE Symposia on Human-Centric Computing Languages and Environments (HCC’03)) to specify visual languages, so to perform usability checks by the management of the production rules. TAGIVE (Cassino et al. (2006): A Methodology for Computer Supported Development of Interactive Visual Applications – WSEAS Transactions On Information Science and Applications Journal.) is the tool that allows to design interactive visual environments and to generate the related formal specification in automatic manner. Thanks to the controls performed at formal level, the system guides the designer in the correct development of the application.