Definition of visual processes in a language for expressing transitions

Domain-specific visual languages are often employed to specify both significant configurations and behaviours of systems of interest for the users. Moreover, behavioural diagrams can be developed for different components of a system, possibly employing different families of diagrams for each subsystem. At an abstract level, these diagrams express some form of system transformation, which can be characterized by its pre- and post-conditions and by a policy presiding at its execution. We propose the WIPPOG language and its computational model for handling such transformations, independently of the adopted diagrammatic notation. We show how the development of interactive systems for the generation of visual sentences and the execution of the visual processes thus specified is achieved by defining a coordinated set of WIPPOG specifications. (C) 2004 Elsevier Ltd. All rights reserved.