Robert C. Williges

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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 approaches and a general lack of understanding of the capabilities and limitations of(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)
Much traditional user interface evaluation is conducted in usability laboratories, where a small number of selected users is directly observed by trained evaluators. However, as the network itself and the remote work setting have become intrinsic parts of usage patterns, evaluators often have limited access to representative users for usability evaluation(More)
Distance learning applications can now make use of networked computers to transmit and display video, audio, and graphics. However, desktop video conferencing systems (DVC) often display degraded images due to bandwidth restrictions and computer processing limitations. The literature on the influence of video parameters such as frame rate and resolution(More)
Individual differences among users of a hierarchical file system were investigated. The results of a previous experiment revealed that subjects with low spatial ability were getting lost in the hierarchical file structure. Based on the concept of visual momentum, two changes to the old interface were proposed in an attempt to accommodate the individual(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)