Gregory M. Corso

Support for multitasking and background awareness using interactive peripheral displays

In this paper, we describe Kimura, an augmented office environment to support common multitasking practices. Previous systems, such as Rooms, limit users by constraining the interaction to the desktop monitor. In Kimura, we leverage interactive projected peripheral displays to support the perusal, manipulation and awareness of background activities. Furthermore, each activity is represented by a montage comprised of images from current and past interaction on the desktop. These montages help remind the user of past actions, and serve as a springboard for ambient context-aware reminders and notifications.

Integrating virtual and physical context to support knowledge workers

The Kimura system augments and integrates independent tools into a pervasive computing system that monitors a users interactions with the computer, an electronic whiteboard, and a variety of networked peripheral devices and data sources.

The Effects of Extended Practice on the Evaluation of Visual Display Codes

A series of nine experiments are reported in which highly practiced subjects were used to investigate the use of letters, digits, familiar geometric shapes, and colored dots as coding dimensions in visual displays. These experiments used single-code and dual-code displays in three isolated tasks (choice reaction, search and locate, and identification-memory) and in a multiple task that combined the three tasks in an irregularly alternating sequence. The results of these experiments provided no basis for concluding that any particular code has a general advantage or disadvantage over any other. Furthermore, when there were differences in performance with different codes, there was a tendency for practice to attenuate those differences. It is concluded that the relative effectiveness of different visual codes varies as a function of practice, other display conditions, the tasks, and the dependent measure used to make the comparison.

Relevant Cues for the Visual Perception of Depth: Is Where You See it Where it is?

We tested seven visual depth cues (relative brightness, relative size, relative height, linear perspective, foreshortening, texture gradient, and stereopsis) at viewing distances of one and two meters to answer two questions. First, which cues provide effective depth information (i.e., only a small change in the depth cue results in a noticeable change in perceived depth). Second, how does the effectiveness of these depth cues change as a function of the viewing distance? Six college-aged subjects were tested with each depth cue at both viewing distances. They were tested using a method of constant stimuli procedure and a modified Wheatstone stereoscopic display. Accuracies for perceptual match settings for all cues were very high (mean constant errors were near zero), and no cues were significantly more or less accurate than any others. Effectiveness of the perspective cues (linear perspective, foreshortening, and texture gradient) was superior to that of other depth cues, while effectiveness of relative brightness was vastly inferior. Moreover, stereopsis, among the more effective cues at one meter, was significantly less so at two meters. These results have theoretical implications for models of human spatial perception and practical implications for the design and development of 3D virtual environments.

Virtual rear projection: do shadows matter?

Rear projection of large-scale upright displays is often preferred over front projection because of the lack of shadows that occlude the projected image. However, rear projection is not always a feasible option for space and cost reasons. Recent research suggests that many of the desirable features of rear projection, in particular shadow elimination, can be reproduced using new front projection techniques. We report on the results of an empirical study comparing two new projection techniques with traditional rear projection and front projection.

Task taxonomies: a general review and evaluation

Abstract The purpose, procedures and issues involved in the development of a task taxonomy were reviewed. A consequence of that review was the development of a set of criteria by which specific task taxonomies can be evaluated and contrasted. Additionally, four general and five specific task taxonomies were reviewed. The specific task taxonomies were evaluated and contrasted using the proposed criteria. From that analysis, it was concluded that future taxonomic efforts must re-evaluate the relative importance of taxonomie development versus the integration of empirical data into a useful, predictive tool.

Auditory temporal order and perceived fusion-nonfusion

A pair of pure-tone sine waves, with the first tone presented randomly to either ear, was presented simultaneously or sequentially. The order of occurrence of the tones (temporal order) and the number of tones perceived (fusion-nonfusion) were judged. Three values of stimulus intensity (40, 55, and 70 dB SPL) and 10 values of stimulus onset asynchrony (SOA; 0, 1, 2, and 4 to 28 msec in 4-msec steps) were varied. Of major importance in this investigation was the relationship between the judgmental tasks of temporal order and fusion-nonfusion. Response time and accuracy were the dependent measures used to assess that relationship. The results of two groups of 10 subjects showed an increase in the percentage of correct nonfusion judgments with increases in stimulus intensity and SOA. For correct judgments of temporal order, no significant intensity or SOA effects were noted. Response time for the fusion-nonfusion task was significantly influenced by both stimulus intensity and SOA. For the response times associated with the temporal order task, intensity was significant. More important to this investigation was the observed Intensity by SOA by Task interaction for response time data. These results suggest a hybrid model, with different processes occurring within different stages of this model.

Redundancy in Coding of a Visual Display as Assessed by a Signal Detection Paradigm

A signal detection paradigm was applied to performance of a visual search task under varying degrees of shape-color redundant coding and two levels of practice. The coding conditions were (1) Black and White, (2) Totally Nonredundant, (3) Partially Redundant, and (4) Totally Redundant. In addition to the traditional signal detection measures, subjective coding condition preference ratings were also recorded. Generally, the objective performance measures were influenced by practice. However, neither the objective nor the subjective measures were affected by coding conditions. A significant Coding Condition by Practice interaction on the percentage of correct responses was also found.

Effects of range on category scaling of loudness judgments.

In two experiments subjects judged the loudness of a 1000-Hz tone within a range of three loudnesses. The first used a within-subjects design with ranges of 1—2 sones, 1—4 sones, and 1—8 sones. The second used a between-subjects design with ranges of 1—2 sones, 1—8 sones, and 1—16 sones. Except for two values in the 1- to 2-sone range the two experiments produced comparable results. As range was increased the tendency to round away from the end points increased and the judged mid-point occurred at a higher value. Comparisons are made with rounding patterns that occur in studies of linear scales. The present results are interpreted to support Poultons (1975) position, that the mid-point of subjective estimates depends on the range of stimuli judged, rather than that of Stevens (1975), that the mid-point on a prothetic scale is assigned to a value that is lower than the mid-point on the subjects subjective scale.

Noise and Annoyance: A New Methodology

Two experiments were conducted to investigate the effects of noise intensity on annoyance. The procedure involved the use of a visual signal to designate the impending occurrence of noise (a 1000-Hz pure tone). If the response was performed within 250 ms, noise was avoided; if the response was performed after 250 ms, the noise occurred but terminated with the response. In the first experiment, the findings indicated that the no-noise condition and 50-dBA values were significantly different from the 90-dBA value for both number of avoidance responses and response latencies. These results imply that avoidance responses and their associated latencies are indicators of annoyance. Experiment 2 investigated range effects on the number of avoidance responses and their latencies. An analysis of the 70-dBA condition for three groups resulted in significant differences between a group exposed to 50, 60, 70 dBA and one exposed to 70, 80, and 90 dBA. These results suggest that both the number of avoidance responses and the associated latencies are not only a function of the absolute intensity value, but are also a function of the range of intensities used. The advantages and disadvantages of the avoidance procedure are discussed.