Visual methods for Web application design

The paper outlines a tool-supported approach to the design of Web applications. Behavioural models are augmented with Web-based simulations of user interfaces to permit validation and usability assessment of systems by end users in advance of implementation. The goal is to correct architectural design decisions that adversely impact usability early in the design cycle when correction is relatively inexpensive. The behavioural model of a system captures the interactions between the different users roles and the set of components that constitute the application. A visual scenario-based language is used to specify interactions and the tool LTSA-MSC is used to synthesise the required behavioural model. The tool supports a visual representation of this model that is animated in response to user-interaction with the simulated Web interface. The combination of these facilities permits agile incremental elaboration of a system design.