Lawrence J. Prinzel

Evaluation of an adaptive automation system using three EEG indices with a visual tracking task

A system was evaluated for use in adaptive automation using two experiments with electroencephalogram (EEG) indices based on the beta, alpha, and theta bandwidths. Subjects performed a compensatory tracking task while their EEG was recorded and converted to one of three engagement indices: beta/(alpha + theta), beta/alpha, or 1/alpha. In experiment one, the tracking task was switched between manual and automatic modes depending on whether the subjects engagement index was increasing or decreasing under a positive or negative feedback condition. Subjects were run for three consecutive 16-min trials. In experiment two, the task was switched depending on whether the absolute level of the engagement index for the subject was above or below baseline levels. It was hypothesized that negative feedback would produce more switches between manual and automatic modes, and that the beta/(alpha + theta) index would be most effective. The results confirmed these hypotheses. Tracking performance was better under negative feedback in both experiments; also, the use of absolute levels of engagement in experiment two resulted in better performance. There were no systematic changes in these effects over three 16-min trials. The implications for the use of such systems for adaptive automation are discussed.

A Closed-Loop System for Examining Psychophysiological Measures for Adaptive Task Allocation

A closed-loop system was evaluated for its efficacy in using psychophysiological indexes to moderate workload. Participants were asked to perform either 1 or 3 tasks from the Multiattribute Task Battery and complete the NASA Task Load Index after each trial. An electroencephalogram (EEG) was sampled continuously while they performed the tasks, and an EEG index (beta/alpha plus theta) was derived. The system made allocation decisions as a function of the level of operator engagement based on the value of the EEG index. The results of the study demonstrated that it was possible to moderate an operators level of engagement through a closed-loop system driven by the operators own EEG. In addition, the system had a significant impact on behavioral, subjective, and psychophysiological correlates of workload as task load increased. The theoretical and practical implications of these results for adaptive automation are discussed.

Effects of a psychophysiological system for adaptive automation on performance, workload, and the event-related potential P300 component

The present study examined the effects of an electroencephalographic- (EEG-) based system for adaptive automation on tracking performance and workload. In addition, event-related potentials (ERPs) to a secondary task were derived to determine whether they would provide an additional degree of workload specificity. Participants were run in an adaptive automation condition, in which the system switched between manual and automatic task modes based on the value of each individuals own EEG engagement index; a yoked control condition; or another control group, in which task mode switches followed a random pattern. Adaptive automation improved performance and resulted in lower levels of workload. Further, the P300 component of the ERP paralleled the sensitivity to task demands of the performance and subjective measures across conditions. These results indicate that it is possible to improve performance with a psychophysiological adaptive automation system and that ERPs may provide an alternative means for distinguishing among levels of cognitive task demand in such systems. Actual or potential applications of this research include improved methods for assessing operator workload and performance.

Adaptive automation of human-machine system information-processing functions.

The goal of this research was to describe the ability of human operators to interact with adaptive automation (AA) applied to various stages of complex systems information processing, defined in a model of human-automation interaction. Forty participants operated a simulation of an air traffic control task. Automated assistance was adaptively applied to information acquisition, information analysis, decision making, and action implementation aspects of the task based on operator workload states, which were measured using a secondary task. The differential effects of the forms of automation were determined and compared with a manual control condition. Results of two 20-min trials of AA or manual control revealed a significant effect of the type of automation on performance, particularly during manual control periods as part of the adaptive conditions. Humans appear to better adapt to AA applied to sensory and psychomotor information-processing functions (action implementation) than to AA applied to cognitive functions (information analysis and decision making), and AA is superior to completely manual control. Potential applications of this research include the design of automation to support air traffic controller information processing.

The Efficacy of Head-Down and Head-Up Synthetic Vision Display Concepts for Retro- and Forward-Fit of Commercial Aircraft

The retrofit question concerns whether useful and effective synthetic vision displays are usable in aircraft that have limited-size display spaces. Two experiments were conducted to examine the efficacy of these displays and develop field-of-view and terrain texture recommendations for design. The first experiment examined issues of field of view and display size using an Asheville, North Carolina, synthetic vision database and fixed-based simulator. The second experiment was conducted on the NASA B-757 aircraft at Dallas/Fort Worth International Airport and investigated the efficacy of both head-down and head-up displays and generic and photorealistic terrain texture. Both experiments confirmed the retrofit capability and that all sizes and texturing methods were found to be viable candidates for synthetic vision displays. These results, future directions, and implications for meeting national aeronautic safety and capacity goals are discussed.

Evaluation of a Psychophysiologically Controlled Adaptive Automation System, Using Performance on a Tracking Task

Three experiments were conducted to evaluate the performance of a psychophysiologically controlled adaptive automation system. Subjects were asked to perform a compensatory tracking task while their electroencephalogram (EEG) was recorded and an engagement index was derived from the EEG, using the alpha, beta, and theta bandwidths: β/(α + θ) and β/θ. In Experiment I, EEG was recorded from three different sites: frontal, parietal, and temporal. Although tracking performance did not differ as a function of site, the number of task mode allocations was greater under a negative feedback contingency than under a positive feedback contingency. This effect was seen primarily from frontal sites. Experiments II and III evaluated the adaptive automation system, using extended runs under positive and negative feedback with either a slope (Experiment II) or absolute (Experiment III) criterion used to drive the system. Using either criterion, performance was found to be significantly better under negative feedback. Future evaluation and use of psychophysiologically controlled adaptive automation systems are discussed.

CFIT prevention using synthetic vision

In commercial aviation, over 30 percent of all fatal accidents worldwide are categorized as Controlled Flight Into Terrain (CFIT) accidents where a fully functioning airplane is inadvertently flown into the ground, water, or an obstacle. An experiment was conducted at NASA Langley Research Center investigating the presentation of a synthetic terrain database scene to the pilot on a Primary Flight Display (PFD). The major hypothesis for the experiment is that a synthetic vision system (SVS) will improve the pilots ability to detect and avoid a potential CFIT compared to conventional flight instrumentation. All display conditions, including the baseline, contained a Terrain Awareness and Warning System (TAWS) and Vertical Situation Display (VSD) enhanced Navigation Display (ND). Sixteen pilots each flew 22 approach / departure maneuvers in Instrument Meteorological Conditions (IMC) to the terrain challenged Eagle County Regional Airport (EGE) in Colorado. For the final run, the flight guidance cues were altered such that the departure path went into the terrain. All pilots with a SVS enhanced PFD (12 of 16 pilots) noticed and avoided the potential CFIT situation. All of the pilots who flew the anomaly with the baseline display configuration (which included a TAWS and VSD enhanced ND) had a CFIT event.

SYNTHETIC VISION ENHANCES SITUATION AWARENESS AND RNP CAPABILITIES FOR TERRAIN-CHALLENGED APPROACHES

The Synthetic Vision Systems (SVS) Project of Aviation Safety Program is striving to eliminate poor visibility as a causal factor in aircraft accidents as well as enhance operational capabilities of all aircraft through the display of computer generated imagery derived from an onboard database of terrain, obstacle, and airport information. To achieve these objectives, NASA 757 flight test research was conducted at the Eagle-Vail, Colorado airport to evaluate three SVS display types (Head-Up Display, Head-Down Size A, Head -Down Size X) and two terrain texture methods (photo-realistic, generic) in comparison to the simulated Baseline Boeing-757 Electronic Attitude Direction Indicator and Navigation / Terrain Awareness and Warning System displays. These independent variables were evaluated for situation awareness, path error, and workload while making approaches to Runway 25 and 07 and during simulated engine-out Cottonwood 2 and KREMM departures. The results of the experiment showed significantly improved situation awareness, performance, and workload for SVS concepts compared to the Baseline displays and confirmed the retrofit capability of the Head-Up Display and Size A SVS concepts. The research also demonstrated that the pathway and pursuit guidance used within the SVS concepts achieved required navigation performance (RNP) criteria.

Nasa Synthetic Vision Ege Flight Test

NASA Langley Research Center conducted flight tests at the Eagle County, Colorado airport to evaluate synthetic vision concepts. Three display concepts (size “A” head-down, size “X” head-down, and head-up displays) and two texture concepts (photo, generic) were assessed for situation awareness and flight technical error / performance while making approaches to Runway 25 and Runway 07 and simulated engine-out Cottonwood 2 and KREMM departures. The results of the study confirm the retrofit capability of the HUD and Size “A” SVS concepts to significantly improve situation awareness and performance over current EFIS glass and non-glass instruments for difficult approaches in terrain- challenged environments.

Flight Testing an Integrated Synthetic Vision System

NASAs Synthetic Vision Systems (SVS) project is developing technologies with practical applications to eliminate low visibility conditions as a causal factor to civil aircraft accidents while replicating the operational benefits of clear day flight operations, regardless of the actual outside visibility condition. A major thrust of the SVS project involves the development/demonstration of affordable, certifiable display configurations that provide intuitive out-the-window terrain and obstacle information with advanced pathway guidance for transport aircraft. The SVS concept being developed at NASA encompasses the integration of tactical and strategic Synthetic Vision Display Concepts (SVDC) with Runway Incursion Prevention System (RIPS) alerting and display concepts, real-time terrain database integrity monitoring equipment (DIME), and Enhanced Vision Systems (EVS) and/or improved Weather Radar for real-time object detection and database integrity monitoring. A flight test evaluation was jointly conducted (in July and August 2004) by NASA Langley Research Center and an industry partner team under NASAs Aviation Safety and Security, Synthetic Vision System project. A Gulfstream G-V aircraft was flown over a 3-week period in the Reno/Tahoe International Airport (NV) local area and an additional 3-week period in the Wallops Flight Facility (VA) local area to evaluate integrated Synthetic Vision System concepts. The enabling technologies (RIPS, EVS and DIME) were integrated into the larger SVS concept design. This paper presents experimental methods and the high level results of this flight test.