Brian R. Johnson

Teleoperation Through Apertures Passability Versus Driveability

Urban search and rescue (USAR) robots get stuck. Furthermore, USAR workers complained that it is difficult to judge whether a teleoperated robot can go through certain apertures. Two experiments tested teleoperators’ abilities to (a) judge whether a robot could fit through apertures (passability), (b) judge whether they could drive a robot through apertures (driveability), and (c) drive the robot through apertures. Experiment 1 examined teleoperators’ passability judgments and whether those same operators hit apertures that were wider than the robot. Experiment 2 replicated Experiment 1 and examined driveability judgments. Experiment 1 indicated that teleoperators made accurate passability judgments and routinely hit apertures that were wider than the robot. Experiment 2 successfully replicated Experiment 1 and demonstrated that teleoperators did not make accurate driveability judgments. Experiment 1 indicated that teleoperating a robot through an aperture is constrained by the robots’ physical dimensions plus a safety margin associated with how well the operators drive the robot. Thus, teleoperators should base decisions to enter an aperture on their ability to drive the robot. However, Experiment 2 indicated that teleoperators do not make accurate driveability judgments. These results have implications for teleoperator training and the design of robots for specific applications.

Why Does the Negative Impact of Inconsistent Knowledge on Web Navigation Persist

Farris (2003) discovered that users had greater difficulty finding information on a Web site when their prior knowledge was inconsistent with the Web sites content, relative to when their knowledge was consistent with it. In addition, he found that this difficulty was persistent over trials. To explain this persistence, Farris offered a schema-based account, which instantiated inconsistency in a single manner. These studies tested 2 predictions that were derived from Farriss account. Specifically, Experiment 1 assessed whether schema elaboration would be gradual, whereas Experiment 2 assessed whether task repetition would eliminate the negative impact of inconsistent knowledge. The results associated with navigation efficiency supported the predictions derived from Farriss account. The results associated with the choices made by participants as they navigated the site, however, contradicted the predictions. A new account, based on production-rules rather than schemata, is offered that considers both sets of results, because it instantiates inconsistency in more than 1 manner. This new account has implications for the design and redesign of Web sites.

Can Metric Feedback Training Hinder Actions Involving Distance

Objective: The present studies tested whether distance estimation training with metric feedback can degrade the performance of untrained primarily perceptual-motor tasks. Background: Training with metric feedback can improve distance estimations. However, previous research led to the conclusion that those improvements stemmed from changes in cognitive processing rather than in perception. If trainees applied their new cognitive strategies to primarily perceptual-motor tasks, then the performance of those tasks should degrade. The present studies tested that possibility. Method: Experiment 1 sought to replicate that training with metric feedback would improve metric distance estimations. Experiments 2 and 3 investigated whether such training would degrade the performance of a primarily perceptual-motor task. Experiment 4 investigated whether such training would affect a perceptual-motor task that required cognition. Results: Metric feedback improved metric distance estimation (Experiments 1—4) and throwing to a specified distance (Experiment 4). Metric feedback degraded throwing to a target (Experiments 2 and 3), although that effect was not evident when pretesting was omitted (Experiment 3). Conclusion: If distance estimation trainees apply what they learned from metric feedback to untrained primarily perceptual-motor tasks, then the performance of those tasks will suffer. However, if trainees apply what they learned to untrained tasks that require metric estimation, then the performance of those tasks will improve. Application: Distance estimation training with metric feedback may not generalize to other tasks and may even degrade performance on certain tasks. Future research must specify the conditions under which distance estimation training with metric feedback leads to performance improvements and decrements.

Real-Time Use of Paper in Air Traffic Control Towers: Criticality and Benefits

The purpose of this study was to gain a better understanding of how and why flight progress strips are currently used in air traffic control towers in the United States. The 3 main staffing positions in the tower, flight-data/clearance delivery (FD/CD), ground control (GC), and local control (LC), were observed by subject-matter experts at 10 control towers. Frequency of occurrence, importance ratings, and type of paper used were recorded. In addition, perceived benefits of marks made on the paper were assessed using open item responses and a series of Likert-scale questions. The positions varied in the marks the controllers made and in their reasons for making the marks. FD/CD controllers tended to make marks because they reduced workload or aided communication. LC tended to make marks because they aided memory, organization, and situation awareness. GC proved to be an interesting hybrid of the FD/CD and LC.

Width guidelines for rectangular objects with penetrable and impenetrable borders

Generally, selection times quicken when objects are placed against a displays edge. Experiment 1 investigated whether or not this continues to be true if the width of those objects, i.e. rectangular scrollbars, was manipulated. The results indicated that increasing width affected selection times for objects with penetrable borders, but not for those with impenetrable borders. A follow-up experiment examined whether or not selection times vary when participants selected very thin and wider scrollbars, each with impenetrable borders. The results indicated that width manipulations did not influence selection time, thus designers could use very thin objects with impenetrable borders without slowing selection time.

Selection of Web Browser Controls with and without Impenetrable Borders: Does Width Make a Difference?

Graphical user interface elements can be selected faster if they are placed against the edge of the screen. Doing so creates an impenetrable border between the element and the edge of the screen that the mouse cursor cannot penetrate, which changes how users move the mouse resulting in quicker selection times. This study assessed the influence of visible width on selection time when targets did or did not have impenetrable borders. Ten participants selected targets that varied in Target Type (with or without impenetrable borders), Width (1, 2, 3, 4, 5 cm), and Distance (2, 4, 8, 16, 32 cm). For a given width, targets with impenetrable borders were always selected faster than targets without impenetrable borders. Also, increasing the width of targets with impenetrable borders had little effect on selection time, whereas doing so when targets did not have impenetrable borders resulted in a substantial effect on selection time. The results indicate that a 1 cm wide target is adequate to make use of the advantage of edge targets in GUI design.

Examining Information Searching on the World Wide Web with a Screen-Reader: A Verbal Protocol Analysis

Recently, assistive devices designed for computer systems have proliferated, including those designed to support users with visual impairments (i.e., screen-readers). However, research examining how individuals use screen-readers to access the Internet is virtually non-existent. Therefore, the purpose of the reported study was to examine the behavior of a user with visual impairment, via protocol analysis, while using the World Wide Web to find information. We classified her behavior into an HCI-relevant model, i.e., Normans (1988) seven stages of action, in order to identify potential usability bottlenecks. The results indicated that executing actions and, more notably, interpreting the system state were the most frequent and time-consuming tasks. In addition, the results suggested that the user had difficulty determining the effects of her control inputs on system status, as well as determining whether or not goal-relevant information was present on the current page. For screen-reader design, this suggests that there are possible usability problems in interfacing the user with the screen-reading software and the way textual information is aurally displayed to the user.

GUI Objects with Impenetrable Borders: Is Instruction Necessary?

Placing menus against the edge of the screen reduces selection times because it creates an impenetrable border between the menu and the edge of the screen that the mouse cursor cannot penetrate (Walker, Smelcer, & Nilsen, 1991). The presence of the impenetrable border changes how users move the mouse, so that selection times quicken compared to menus with a penetrable border. However, it is not readily apparent whether or not GUI users could realize the advantages of impenetrable borders without instruction. The purpose of this experiment was to assess whether or not users would discover the benefits of impenetrable borders spontaneously. Results suggest that only 50% of participants who were unaware of the presence of the impenetrable border actually detected it. Additionally, with practice participants who were successful at detecting the impenetrable border selected the targets as quickly as participants who received full instruction concerning the benefits of impenetrable borders.

Dimensions of Air Traffic Control Tower Information Needs: From Information Requests to Display Design

In an effort to determine the information needs of tower air traffic controllers, instructors from the Federal Aviation Administrations Academy in Oklahoma City were asked to control traffic in a high-fidelity tower cab simulator. Information requests were made apparent by eliminating access to standard tower information sources. Instead, controllers were required to ask for precisely the information they needed during the scenarios. The information requests were classified using an elaboration of Zwaan and Radvanskys (1998) dimensions of situation models. The vast majority of requests were about three of the dimensions originally developed for reading comprehension: the protagonist, intentionality, and space. The information requests were also classified into 28 operational categories (e.g., aircraft identification, destination). From these results, the data were summarized, not just statistically, but by the creation of display-hypotheses. The display-hypotheses were organized according to the situation-model dimensions. Controllers preferred data blocks organized by the situation-model principle over those that violated this organization. The summary display-hypotheses were quite simple and accounted for the vast majority of the information requests controllers made. The display-hypotheses accounted for the information needs of controllers during routine as well as off-nominal events.

When do People Generate their Best Ideas

Using the electronic brainstorming technique, participants brainstormed ideas in three-person groups. After brainstorming for 15 minutes, participants received a paper transcript that contained all of their generated ideas and then they were asked to individually select the five best ideas. When selecting ideas, participants had an affinity for ideas that were generated early. For instance, 23% of participants selected the very first idea that was generated as their very best idea. Furthermore, over half of the participants (51%) selected one of the first five ideas that were generated as their very best idea. This was notable considering the average group generated 55 ideas. This finding may be beneficial in that it could shorten the brainstorming process.