Amy L. Alexander

University of Illinois, Urbana-Champaign, Urbana, Illinois, United States

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Publications (32)4 Total impact

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    Human Factors and Ergonomics Society Annual Meeting Proceedings 02/2014;
  • Journal of Aerospace Computing, Information and Communication 01/2013; 10(8):359-368. · 0.21 Impact Factor
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    ABSTRACT: This study was conducted to: develop a multidimensional measure of display clutter for advanced head-up displays (HUDs) incorporating enhanced and synthetic vision; assess the influence of HUD configuration on perceptions of display clutter, workload, and flight performance; model clutter scores in terms of visual display properties; and model flight performance in terms of subjective and objective clutter indices. In a flight simulator, 18 pilots with different levels of flight experience flew approaches divided into three segments. Three HUD configuration sets were presented under two levels of flight workload. Pilot ratings of overall display clutter, its underlying dimensions, and mental workload were recorded along with flight performance measures. Display image analysis software was used to measure visual properties of the HUDs. The multidimensional measure of clutter showed internal consistency with overall perceived clutter. Calculated clutter scores were sensitive to HUD configurations and in agreement with a priori display classifications. There was a trend for the extremes of display clutter to cause higher workload and less stable performance due to cognitive complexity and a lack of information for high and low clutter displays, respectively. Multiple linear regression models of perceived clutter were developed based on HUD visual properties with predictive utility. Models of flight performance based on the clutter score and workload ratings were also developed, but with less predictive power. Measures and models of display clutter are expected to be applicable to the evaluation of a range of display concepts.
    Aviation Space and Environmental Medicine 11/2011; 82(11):1013-22. · 0.78 Impact Factor
  • Proceedings of the Twenty-Second Conference on Innovative Applications of Artificial Intelligence, July 11-15, 2010, Atlanta, Georgia, USA; 01/2010
  • Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2009; 53(1):21-25.
  • Christopher D. Wickens, Amy L. Alexander
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    ABSTRACT: This article discusses attentional tunneling as one cause of breakdowns in task management. The phenomenon is defined, and it is shown how it can be induced by head-up display location, and compelling 3-dimensional perspective displays. The results of 6 experiments using a synthetic vision display, with or without a highway in the sky (HITS) display are then summarized, as these reveal the attention tunneling phenomenon manifest in the failure to detect unexpected air hazards. Two factors that enhance this phenomenon are identified: location away from the center of visual scan and the presence of the HITS.
    International Journal of Aviation Psychology - INT J AVIAT PSYCHOL. 01/2009; 19(2):182-199.
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    ABSTRACT: Synthetic vision systems provide an in-cockpit view of terrain and other hazards via a computer-generated display representation. Two simulator-based experiments examined several display concepts for synthetic vision and evaluated how such displays modulate pilot performance. Experiment 1 (24 general aviation pilots) compared 3 navigational display (ND) concepts: 2D coplanar, 3D, and dual-perspective. Experiment 2 (12 commercial airline pilots) evaluated baseline “blue sky–brown ground” or synthetic-vision-enabled primary flight displays (PFDs) and 3 ND concepts: 2D coplanar with and without synthetic vision and a dynamic multimode rotatable exocentric format. In general, the results pointed to an overall advantage for a dual-perspective format, whether it be stand-alone (Experiment 1) or available via rotatable viewpoints (Experiment 2). Furthermore, Experiment 2 revealed benefits associated with utilizing synthetic vision in both the PFD and ND representations and the value of combined ego- and exocentric presentations.
    International Journal of Aviation Psychology - INT J AVIAT PSYCHOL. 01/2009; 19(2):105-130.
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    ABSTRACT: Synthetic and enhanced vision systems (SVS and EVS) are being introduced into the cockpit to promote safety under workload conditions. Integration of existing iconic imagery with SVS and EVS displays may lead to perceptions of clutter. This research evaluated head-up display (HUD) features, including SVS, EVS, traffic collision avoidance system symbology, flight pathway (TUNNEL) guidance, and different primary flight display symbol sets, on pilot perceptions of clutter. A perceptual decomposition of the construct of clutter was also conducted. During a simulated landing, 4 expert pilots viewed images of 16 HUD configurations. Pilots rated clutter for each image and the utility of pairs of terms for describing clutter. Results revealed all HUD features and two-way interactions to be significant in perceived clutter. Ratings increased with additional features. The presence of EVS, TUNNEL, and an expanded symbol set contributed the most. Regression models were developed to predict the likelihood of clutter ratings based on pilot perceptions of display characteristics. Pairs of terms found to have the greatest use for describing clutter included "redundant/orthogonal," "monochromatic/colorful," "salient/not salient," "safe/unsafe," and "dense/sparse" (in that order). A factor analysis revealed underlying display qualities explaining approximately 78% of variability in perceived clutter, including global density, feature similarity, feature clarity, and the dynamic nature of displays. These qualities corresponded with the display descriptor terms plus the terms "static/dynamic." The study provided information on the relationship of display features and pilot perceptions of clutter. We identified terminology pilots use to describe clutter and latent display variables that drive perceived clutter.
    Aviation Space and Environmental Medicine 12/2008; 79(11):1007-18. · 0.78 Impact Factor
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    ABSTRACT: Aptima, Inc. The tremendous expense and inherent dangers of training in the aircraft have led to the increased use of simulators for practicing and maintaining air combat skills; However, the advantages and disadvantages of using high or low-fidelity simulators for such training must be specified. An experiment was conducted to examine the in-simulator performance differences between pilots flying lower-fidelity simulators compared to higher-fidelity simulators. The primary difference between the two simulators is the visual scene field-of-view. Sixteen U.S. Air Force F-16 pilots flew standard training missions as an integrated team of four (a "four-ship") with two pilots flying in the high-fidelity simulators and two pilots flying in the lower-fidelity simulators. Various subjective and objective measures were collected to assess the pilots' ability to maintain a briefed formation. Overall, the results suggest that pilots who practice four-ship employment in the lower-fidelity simulators can perform at the same level as those who practice in the high-fidelity simulators. Future analyses should be conducted to examine the impact of simulator fidelity on other air combat skills and on training effectiveness.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2007; 51(2).
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    Amy L Alexander, Christopher D Wickens
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    ABSTRACT: Synthetic vision systems, of which integrated hazard displays may be an integral component, are being developed to allow for safe and efficient navigation through terrain-challenging or low-visibility conditions. In this study, 24 pilots flew a series of approaches while maintaining their position within a highway in the sky and responding to periodic queries regarding traffic location as represented within the integrated hazard display. Eye-movement data were examined to determine the effects of visual scanning behaviors on pilot performance (flight control, traffic awareness, and off-normal event detection). Overall, all pilots treated the flight task of aviating as primary, giving it the attentional resources required to maintain adequate performance. While scanning patterns were relatively equivalent between the off-normal event detection groups, the detectors did not appear to be as attentionally tunneled to the compelling SVS suite as the non-detectors, given that they were able to notice and respond to the non-database tower visible only in the outside world. In fact, pilots who failed to detect the off-normal event spent less time scanning the outside world on the relevant trial, where the ground truth information was represented. The results are interpreted within a task management framework mediated by performance resource functions.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2006; 50(1).
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    ABSTRACT: Large, complex organizations implement a range of policies and procedures to protect against risk. Sometimes, however, catastrophic accidents occur, such as with the Challenger and Columbia shuttles. "Procedural drift" has been suggested as a source of such accidents (Rasmussen, Pejtersen, & Goldstein, 1994), a process whereby procedures gradually shift, based on operating experience, until an extreme situation causes the shifted procedures to fail. Brief case studies were conducted of the shuttle accidents to explore and refine this hypothesis and to develop methods for investigating it systematically, including a "knowledge map" method, initially described by Lintern (2003). A knowledge map is a theoretically-driven variant of a work domain analysis (Rasmussen et. al., 1994), which incorporates procedural task analysis and organizational controls to analyze the overarching goal of the system. This enables visualization of how procedures occur within the organization, describing collaborations, decisions, and management procedures. Secondary goals are achieved through tasks, and tasks are further broken down into sub-tasks to describe how the system, at its procedural level, acts within the global constraints of the system. Since the knowledge map method does not generate runnable models, a system dynamics model was also developed to model the processes and dynamics of procedural drift, particularly as it affects safety. This combination of methods shows considerable promise in analyzing the shuttle accidents in particular and procedural drift and organizational risk in general.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2006; 50(19).
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    Amy L. Alexander, Christopher D. Wickens
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    ABSTRACT: Twenty-four certified flight instructors were required to fly a series of curved, step-down approaches while detecting changes to surrounding traffic aircraft and weather cell icons on two integrated hazard display (IHD) formats (2D coplanar and split-screen) under varying workload levels. Generally, it appears that the 2D coplanar IHD was better in supporting flightpath tracking and change detection performance when compared to a split-screen display. Pilots exhibited superior flightpath tracking (in the vertical dimension, and under low workload) when using the 2D coplanar IHD, although this effect was mitigated by increasing workload such that tracking deteriorated faster with the 2D coplanar than the split-screen display. The spawned 3D cost of diminished size with distance from ownship played a role in change detection response time—pilots were slower (particularly in detecting traffic aircraft changes) with the split-screen compared to the 2D coplanar IHD. These effects will be discussed within the context of visual scanning measures.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 09/2005; 49(1).
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    ABSTRACT: Two experiments conducted in a high-fidelity flight simulator examined the effects of guidance symbology, display size, and geometric field of view (GFOV) within a synthetic vision system (SVS). In Experiment 1, 18 pilots flew highlighted and low-lighted tunnel-in-the-sky displays, as well as a less cluttered follow-me aircraft (FMA), through a series of curved approaches over rugged terrain. The results revealed that both tunnels supported better flight path tracking and lower workload levels than did the FMA because of the availability of more preview information. Increasing tunnel intensity had no benefit on tracking and, in fact, degraded traffic awareness because of clutter and attentional tunneling. In Experiment 2, 24 pilots flew a lowlighted tunnel configured according to different display sizes (small or large) and GFOVs (30 degrees or 60 degrees). Measures of flight path tracking and terrain awareness generally favored the 60 degrees GFOV; however, there were no effects of display size. Actual or potential applications of this research include understanding the impact of SVS properties on flight path tracking, traffic and terrain awareness, workload, and the allocation of attention.
    Human Factors The Journal of the Human Factors and Ergonomics Society 02/2005; 47(4):693-707. · 1.18 Impact Factor
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    ABSTRACT: In 3 experiments, we examined maneuver choice, flight safety, and mental workload across 3-dimensional (3D) perspective and 2-dimensional coplanar cockpit displays of traffic information in a free-flight simulation. In Experiment 1 (30 pilots), we examined dimensionality issues; in Experiments 2 and 3 (18 pilots each), we examined the effects of traffic density, dimensionality, and vertical profile orientation. Collectively, these data may be modeled by trade-offs between the display types: The coplanar suite suffers from scanning-related integration that increases with conflict density; the 3D display suffers from perceptual ambiguity. This research informs our understanding of how displays modulate performance in free-flight environments.
    International Journal of Aviation Psychology - INT J AVIAT PSYCHOL. 01/2005; 15(1):1-21.
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    Human Factors and Ergonomics Society Annual Meeting Proceedings 09/2004; 48(1).
  • Amy L Alexander, Christopher D Wickens
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    ABSTRACT: The ability for pilots to estimate traffic location, and how such estimations should be measured, was examined within an Integrated Hazard Display context. Twelve pilots viewed static images of traffic scenarios and then estimated the outside world locations of queried traffic represented in one of three display types (2D coplanar, 3D exocentric, and split-screen) and in one of four conditions (display present/blank crossed with outside world present/blank). Overall, the 2D coplanar display best supported both vertical (compared to 3D) and lateral (compared to split-screen) traffic position estimation performance. Furthermore, although pilots were faster in estimating traffic locations when the display was blank, accuracy was greatest when both the display and outside world were available.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 09/2004; 48(1).
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    ABSTRACT: Two experiments were conducted in which participants performed a vehicle dispatching task. The intensity of one information source (vehicles in Experiment 1, destinations in Experiment 2) was varied to examine the effects of salience and discrimination on both searching for and processing the information in a cluttered display. Response times were recorded for questions either requiring focused attention on or divided attention between the different information domains in the map. The results of the present experiments indicate that it is possible to declutter a display without erasing any information. By 'lowlighting' one information domain and keeping the other domain at a fairly high intensity level, dividing attention between the information sources is optimal, as is focusing attention on either of the information domains exclusively. These results are discussed in conjunction with a computational model of confusion and salience which serves to predict search and integration performance in a cluttered display with separate domains of information displayed at different intensities.
    Spatial Vision 02/2004; 17(4-5):373-88. · 1.04 Impact Factor
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    DSC North America Proceedings. 11/2003;
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    ABSTRACT: Two experiments conducted in a high-fidelity flight simulator examined the effects of guidance symbology, display size, and field of view (FOV) on flight performance and situation awareness within a Synthetic Vision System (SVS). In Experiment 1, 18 pilots flew highlighted and lowlighted tunnel-in-the-sky displays and a less-cluttered follow-me-aircraft (FMA) through a series of curved approaches over rugged terrain. The results revealed that both tunnels supported better flightpath tracking than the FMA due to the availability of more preview information. Increasing tunnel intensity had no benefit on tracking, and in fact, traffic awareness was degraded. In Experiment 2, 24 pilots flew a lowlighted tunnel display configured according to different display sizes (small or large) and FOVs (30° or 60°). Measures of flightpath tracking and terrain awareness generally favored the smaller display and the 60° FOV.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2003; 47(1).
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    ABSTRACT: The present experiments were designed to assess the influence of display size, display highlighting, and event eccentricity in a surveillance task. Pilots were asked to detect changes in the movement or altitude of weather systems or traffic aircraft, which were represented in integrated hazard displays. Experiment 1 examined change detection as a function of the distance of the event from ownship and the presence of the event in a highlighted or lowlighted hazard domain. Analyses revealed that change detection was superior for events that were in the highlighted display database and that performance was slightly degraded for more eccentric events. Experiments 2 and 3 assessed the role of display size and event eccentricity. Analyses showed that change detection was unaffected by the size of the display, though performance was again degraded for changes located near the perimeter of the display. Findings imply that surveillance of the display perimeters will depreciate and additional methods should be used to ensure that attention is sufficiently directed to these areas.
    Human Factors and Ergonomics Society Annual Meeting Proceedings 10/2003; 47(1).