Specifying dialog control in visual interactive systems

Dialog control is a crucial component of a visual interactive system. A demanding requirement is that it both allows freedom to perform actions according to the user's intentions and yet ensures that only legal actions may be performed. To meet this requirement, we propose a formal method based on the definition of human-computer interaction as generation and interpretation of visual sentences which constitute a visual language. Such a language can be specified in a finitary way by means of visual conditional attributed rewriting systems. A number of algorithms demonstrate how a specific family of such systems is suited ts the automatic derivation of an automaton controlling dialogue in visual interaction. (C) 1998 Academic Press.