Graphically enhanced keyboard accelerators for GUIs

We present the design and evaluation of Graphically Enhanced Keyboard Accelerators (GEKA), a user interface interaction method allowing commands within a graphical application to be quickly and easily invoked through the keyboard. The high-level goal of this work is to make interactive desktop computing more pleasant and productive for experienced computer users. GEKA is designed to provide complete coverage of the command set, to require low visual demand, and to support ease of learning and remembering, a low error rate, and high speed. This thesis describes GEKA's design and two related user studies. A formative study with 10 participants explored how our target users currently work with Window, Icon, Menu and Pointer (WIMP) interfaces. The results of the study suggest that advanced computer users prefer to execute commands with the keyboard. However, they are often unable to do so in current applications because shortcuts are not available for all commands or are unknown. This indicates a desire among advanced users for a GEKA-like interaction method and motivates our research. GEKA’s design blends elements from WIMP and command line interfaces, allowing commands to be entered quickly and precisely while shifting the focus of the interaction to recognition rather than recall. GEKA has three key improvements over existing text command systems with graphical feedback: support for multiple parameters in arbitrary order, smarter matching – including abbreviations for all commands, and clear visual feedback of the input characters to facilitate learning and re-use. A laboratory experiment with 12 participants compared GEKA to WIMP interaction methods. We found error rates to be nearly identical and speed to be very competitive. The experiment also explored users’ preferences: When given a choice in situ between WIMP and GEKA for actual command execution, participants overwhelmingly used existing keyboard shortcuts when they knew them and used GEKA when they didn’t. In a questionnaire, each type of GEKA command was rated better than its WIMP equivalent except for zero-parameter GEKA commands relative to keyboard shortcuts. These results suggest that our target user population has a strong preference for GEKA interaction over the mouse-based WIMP methods.Science, Faculty ofComputer Science, Department ofGraduat