The UAN: A User-Oriented Representation for Direct ManipulationInterface Designs

Almost all existing interface representation techniques, especially those associated with UIMS, are constructional, focused on interface implementation, and therefore do not adequately support a user-centered focus. But it is the behavioral domain of the user that interface designers and evaluators do their work. We are seeking to complement constructional methods by providing a tool supported technique capable of specifying the behavioral aspects of an interactive system -- the tasks and the actions a user performs to accomplish those tasks. In particular, this paper is a practical introduction to use of the User Action Notation (UAN), a task- and User-oriented notation for behavioral representation of asynchronous, direct manipulation interface designs. Interfaces are specified in the UAN as a quasi-hierarchy of asynchronous tasks. At the lower levels, user actions are associated with feedback and system state changes. The notation makes use of visually onomatopoeic symbols, and is simple enough to read without much instruction. The UAN has been used by growing numbers of interface developers and researchers over the past few years. In addition to its design role, current research is investigating how the UAN can support the production and maintenance of code and documentation.