Abstract

Theseparation of interactive systems into a computational component and a dialogue component, allowed the upcoming of specific technology for user-interface implementation. However, despite the great amount of available technology, building a user interface is still an hard and time consuming process. So an effort to study and develop formal human-computer dialogue specification methodologies is being made, with the goal of devising quicker and safer development processes and techniques.

The user interface of an interactive system should not be just a passive transmition channel between the user and the application, but a reflex of the application, allowing the user to better understand the application's internal state and therefore making the dialogue easier. The strict separation between computational layer and dialogue layer, proposed by many models, does not allow the development of this kind of user interface, as the semantic information is trapped in the computational component.

Starting from this considerations, a dialogue specification formalism was studied and implemented - Guiões de Interacção (Interaction Scripts, GI's) - which allow the inclusion of semantic conditions into the specification, making it possible to clearly express the dynamic components of the dialogue, particularly "application context sensitive dialogues" The use of an a la CCS notation allowed the specification of concurrent dialogues. Petri Nets were used as a mean of expressing the operational semantics and as an implementation model for GI's.