Timetrees: A Branching-Time Structure for Modeling Activity and State in Human-Computer Interaction
Jeffrey L. Brandenburg, H. Rex Hartson · Human-Computer Interaction · 1999
The design and construction of usable interactive systems requires a user-centered approach to system development. Such an approach requires tools and representations reflecting a behavioral view of the interface-a view centered on user activities and the system activities and states that the user can perceive. We present a model of these behavioral phenomena well suited for defining, extending, and analyzing behavioral representations. Our model is based on the timetree, a novel tree-based structure representing tasks, user actions, system activity, and system and interface state, all within a framework of branching sequential timelines. We introduce the timetree model by relating it to well-known interactive behaviors. We present a formal definition of timetrees and some of the operations they support, and we show some ways in which the model has contributed to our understanding of behavioral descriptions.