Robert C. Williges

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The current variety of alternative approaches to usability evaluation methods (UEMs) designed to assess and improve usability in software systems is offset by a general lack of understanding of the capabilities and limitations of each. Practitioners need to know which methods are more effective and in what ways and for what purposes. However, UEMs cannot be(More)
A series of 3 studies was conducted to test free-modulus magnitude estimation as a measure of perceived presence in virtual environments (VEs) and to model the first- and second-order effects of 11 VE system parameters on perceived presence across 5 subtasks. Sequential experimentation techniques were used to build 4 empirical models using polynomial(More)
Despite the increased focus on usability and on the processes and methods used to increase usability, a substantial amount of software is unusable and poorly designed. Much of this is attributable to the lack of cost-effective usability evaluation tools that provide an interaction-based framework for identifying problems. We developed the user action(More)
Submitted for publication; do not copy or cite without permission. ABSTRACT Among interactive system developers and users there is now much agreement that usability is an essential quality of software systems. The introduction of usability evaluation methods (UEMs) to assess and improve usability in such systems has led to a variety of alternative(More)