Computer Analysis of User Interfaces

Interface evaluation is a necessary phase in the production of quality user interfaces. The usual evaluation techniques involve formal experiments or observation, and can be invasive. One non-invasive method that can be used at user sites is to record all user input and system output to a file. This transcript is then algorithmatically analyzed to determine interface problems. A new technique analyzes these transcripts by searching for maximal repeating patterns (MRPs), on the hypothesis that repeating sequences of user actions indicate interesting user behavior, and therefore may show problems in the interface. The technique was tested by using it to evaluate the human-computer interface of a large and complex image processing system in active use. Results show MRPs useful in detecting specific problems within the interface

Notational Techniques for Accommodating User Intention Shifts

Good user interface designs allow for user intention shifts. The asynchronous nature of direct maniulation interfaces inherently demands consideration of user intention shifts during the performance of a task. Maintaining a focus on the primary function of a task while at the same time accommodating user intention shifts is difficult for interface designers when both these aspects are represented at the same design level. The User Action Notation (UAN), a technique for representing asynchronous interfaces, contains a mechanism for specifying points in a task where user intention shifts may occur. A complementary technique, Task Transition Diagrams (TTDs), is used to specify tasks that users can perform to interrupt their current task. The Task Transition Diagram is a notation that allows a designer to map out the set of tasks and intentions of users without having to be concerned with the minutiae of how a user accomplishes those tasks

Task-Oriented Representation of Asynchronous Interfaces

A simple, task-oriented notation for describing user actions in asynchronous user interfaces is introduced. This User Action Notation (UAN) allows the easy association of actions with feedback and system state changes as part of a set of asynchronous interface design techniques, by avoiding the verbosity and potential vagueness of prose. Use within an actual design and implementation project showed the UAN to be expressive, concise, and highly readable because of its simplicity. The task-and user-oriented techniques are naturally asynchronous and a good match for object-oriented implementation. Levels of abstraction are readily applied to allow definition of primitive tasks for sharing and reusability and to allow hiding of details for chunking. The UAN provides a critical articulation point, bridging the gap between the task viewpoint of the behavioral domain and the event-driven nature of the object-oriented implementational domain. The potential for UAN task description analysis may address some of the difficulties in developing asynchronous interfaces

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

Computer Analysis of User Interfaces Based on Repetition in Transcripts of User Sessions

It is generally acknowledged that the production of quality user interfaces requires a thorough understanding of the user and that this involves evaluating the interface by observing the user working with the system, or by performing human factors experiments. Such methods traditionally involve the use of video tape, protocol analysis, critical incident analysis, etc. These methods require time consuming analyses and may be invasive. In addition, the data obtained through such methods represent a relatively small portion of the use of a system. An alternative approach is to record all user input and systems output, i.e., log the user session. Such transcripts can be collected automatically and non-invasively over a long period of time. Unfortunately, this produces voluminous amounts of data. There is, therefore, a need for tools and techniques that allow an evaluator to identify potential performance and usability problems from such data. It is hypothesized that repetition of user actions is an important indicator of potential user interface problems

Interactive Digital Video Authoring and Prototyping

This paper reports on a joint research project between Virginia Tech and the NCR Corporation on Digital Video Interaction (DVI) technology. In particular, it discusses