Sang Hwan Kim

Multidimensional measure of display clutter and pilot performance for advanced head-up display.

INTRODUCTION 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. METHODS 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. RESULTS 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. DISCUSSION Measures and models of display clutter are expected to be applicable to the evaluation of a range of display concepts.

Bottom-up and Top-down Contributors to Pilot Perceptions of Display Clutter in Advanced Flight Deck Technologies

Future concepts for the National Airspace System rely on technologies, such as synthetic and enhanced vision systems, to support flight efficiency associated with improved terrain and traffic awareness. While these technologies provide the pilot access to information not available with traditional flight instrumentation, the presentation of this additional information may serve to produce display clutter, thus inhibiting the processes and tasks they are designed to support. An experiment was conducted to assess pilot perceptions and identification of both bottom-up (data-driven) and top-down (knowledge-driven) contributing factors to display clutter. Results revealed the importance of both visual and information density (bottom-up and top-down factors, respectively) to the perception of clutter. Although added display elements provided pilots with critical flight information, pilots considered displays to be cluttered when the imposed visual density exceeded the information density required for specific flight tasks. These findings suggest that moderate levels of display clutter may be tolerable, to the extent that the information is relevant to the tasks at hand.

Measurement and Modeling of Display Clutter in Advanced Flight Deck Technologies

Clutter is a key concern in the design of complex displays, particularly in safety-critical domains such as aviation. The objective of this research was to investigate techniques for measuring subjective perceptions of clutter and to model the predicted impacts of clutter on pilot performance within the context of advanced flight deck technologies. Six commercial pilots flew simulated approaches under varied workload conditions with low-, medium-, and high-clutter head-up displays, rating the perceived clutter and subjective mental workload associated with each display configuration. Results revealed that high-clutter displays produced elevated reports of perceived clutter and workload due to information density or redundancy, whereas low-clutter displays were perceived as less cluttered but challenging to use due to lack of relevant information typically used during flight. A multidimensional measure of clutter was found to be more sensitive to display differences than an overall perceived rating of clutter, and low-level visual display properties were successful in predicting clutter perceptions and pilot performance. Finalized products of this research could support optimized display design through the identification of clutter thresholds and the implementation of clutter alerts, decluttering mechanisms, or both, and could be used to support display certification and acquisitions processes.

Computational Cognitive Modeling of Operator Behavior in Telerover Navigation

The objective of this study was to demonstrate the use of a computational cognitive model for representing human performance in robotic rover control and to make comparison with actual human performance. In manual control trials, an operator was required to navigate a commercially available rover along a path using a remote workstation. A cognitively plausible GOMSL (Goals, Operators, Methods, Selection rules) model for controlling the rover was constructed based on a task analysis and observations during the human trials. Time-to-navigation completion and path tracking accuracy were recorded during the human performance and cognitive model trials with navigation conditions being identical. Model output demonstrated the GOMSL code to produce more precise control of the rover than human performance, but this was at the cost of time. This result was attributable to limitations of the modeling approach in terms of representing human parallel processing and continuous control. In general, computational GOMS modeling approaches appear to have the potential to describe interactive closed-loop system control with continuous monitoring of feedback and corresponding control actions.

Testing and Validation of a Psychophysically Defined Metric of Display Clutter

Combinations of cockpit display features may lead to increased pilot perceptions of clutter. This research sought to capture pilot perceptions of display clutter associated with primary flight display features during a vertical takeoff and landing scenario and to validate a multidimensional measure of clutter previously developed for a fixed-wing environment. Sixteen active fixed-wing pilots were recruited for the study that used a simulator configured as a vertical takeoff and landing aircraft. A factor analysis was used to reduce the number of subdimensions of the clutter measure based on previous ratings data. The simplified measure revealed an increase in the number of active display features to cause an increase in perceived clutter. Displays including synthetic vision system features were perceived as significantly more cluttered than those without. Although a tunnel (highway in the sky) feature also contributed to clutter, pilots achieved higher navigation system failure detection rates when the fe...

Assessing the Effects of Conformal Terrain Features in Advanced Head-Up Displays on Pilot Performance

The objective of this study was to assess the effect of Synthetic Vision System (SVS) and/or Enhanced Vision System (EVS) rendering of terrain features on pilot performance, including path control and situation awareness (SA), when presented in an advanced head-up display (HUD) during various phases of a landing approach under instrument meteorological conditions (IMCs). Results indicated that SVS imagery increase overall SA but degraded flight path control performance due to visual confusion with other display features. EVS increased flight path control accuracy but decreased system awareness by creating visual distractions for pilots (moisture returns), while they were focused on path control. The combination of SVS and EVS generated offsetting effects but there were still decrements in performance in the final landing phase due to overall HUD clutter. In general, display configurations in this study did not affect pilot spatial awareness but there was an influence on awareness of (iconic) system information. An IMC-day condition produced worse pilot performance than night flight because of reduced visual saliency of HUD information features. Flight performance was not different between phases of approach but levels and types of pilot SA did vary from leg to leg.

Understanding Cognitive Strategy With Adaptive Automation in Dual-Task Performance Using Computational Cognitive Models

The objectives of this study were to investigate the effects of advance auditory cuing of control mode changes in an adaptively automated system on human performance and to explain cognitive behaviors at mode changes by using a computational cognitive model. A dual-task piloting simulation, involving tracking and tactical decision making, was developed to collect human performance data with auditory cuing or no cuing of mode transitions in the tactical task. Computational GOMS (goal, operators, methods, and selection) language models were coded to simulate user behavior on the basis of expectation of increased memory transactions (between long-term and working stores) at mode transitions. The models were applied to the same task simulation and scenarios performed by the humans. Human performance data did not reveal differences between cued and no-cue trials possibly because of distraction from the tracking (secondary loading) task. Comparison of results for human and model output demonstrated the model to be descriptive of the pattern of human performance across conditions but not accurate in predicting timing of memory use in preparing for manual control. A refined GOMS language model was coded on the basis of a modified assumption that memory stores are used on an ad hoc basis after high-workload mode transitions and with consideration of human parallel processing in dual-task performance. Results revealed the refined model to have greater plausibility for representing actual behavior. The manner of operator use of memory stores for controlling an adaptive system provides insight into the impact of cuing of mode transitions and a basis for future systems design.

Assessing Usability of Human–Machine Interfaces for Life Science Automation Using Computational Cognitive Models

The objective of this study was to assess the plausibility of using computational cognitive models for evaluating the usability of human–machine interfaces in supervisory control of high-throughput (biological) screening (HTS) operations. Usability evaluations of new interface prototypes were conducted by comparisons with existing technologies. Model assessment occurred through comparison with human test results. Task completion times and the number of errors were recorded during human performance trials, and task time was predicted in cognitive model trials in tests with two HTS interfaces. Computational GOMSL (Goals, Operators, Methods, and Selection rules Language) models were constructed based on a combination of cognitive task analyses (abstraction hierarchy modeling and goal-directed task analysis). The usability tests revealed improvements in task performance with the new prototypes. The cognitive model outputs were correlated with actual human performance, and the approach was considered useful for evaluating the usability of new interfaces in life sciences automation in the future.

Design and Usability Evaluation of Foot Interfaces for Dynamic Text Editing

The objective of this study was to design and evaluate the use of foot pedal controls for dynamic text editing. An experiment was conducted to assess whether the new foot control method would improve editing performance, compared to conventional mouse use, and to identify specific types of foot control most convenient for users. Four prototype methods involving use of two foot pedals vs. one pedal with zero-order or first order control were developed and tested against mousing in an editing task with dynamic changes in text size (e.g., instant messaging). Prototype methods involving first order control were found to be comparable to the mouse method in task completion time, accuracy and subjective workload. Among the four prototypes, foot control using two pedals with first order control was superior to the other methods, in performance. Consequently, foot pedals may be effectively utilized in computing operations, particularly dynamic text editing tasks, as an alternative or additional input device. Furthermore, such methods may be particularly suited for special populations.

Influence of Flight Domain and Cockpit Display Dynamics on Pilot Perceived Clutter

Two analyses were conducted on three datasets from a series of aviation human factors experiments focused on the development and testing of measures of flight display clutter as well as the relation with flight task performance. The objectives of this study were to assess the effects of cockpit display dynamics and aircraft type on pilot perceptions of display clutter in simulated flight tasks through statistical analyses of the data gathered across the experimental studies. Comparisons were made on observations of pilots with comparable experience under similar headup or headdown display conditions. In general, this research demonstrated the clutter measures to be highly sensitive to aviation display and domain conditions. The findings also indicated that human information processing considerations in aviation display design coupled with attention to the visual characteristics of display features may provide an effective basis for mitigating potential effects of clutter on pilot performance.