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Hart, Sandra G.

Publications and source records attributed to Hart, Sandra G..

36 records · Page 2
All sourcesNASA NTRSDOE OSTI
NASA NTRS1988

Helicopter human factors research

Helicopter flight is among the most demanding of all human-machine integrations. The inherent manual control complexities of rotorcraft are made even more challenging by the small margin for error created in certain operations, such as nap-of-the-Earth (NOE) flight, by the proximity of the terrain. Accident data recount numerous examples of unintended conflict between helicopters and terrain and attest to the perceptual and control difficulties associated with low altitude flight tasks. Ames Research Center, in cooperation with the U.S. Army Aeroflightdynamics Directorate, has initiated an ambitious research program aimed at increasing safety margins for both civilian and military rotorcraft operations. The program is broad, fundamental, and focused on the development of scientific understandings and technological countermeasures. Research being conducted in several areas is reviewed: workload assessment, prediction, and measure validation; development of advanced displays and effective pilot/automation interfaces; identification of visual cues necessary for low-level, low-visibility flight and modeling of visual flight-path control; and pilot training.

Nagel, David C.↗
NASA NTRS1988

An integrated approach to rotorcraft human factors research

As the potential of civil and military helicopters has increased, more complex and demanding missions in increasingly hostile environments have been required. Users, designers, and manufacturers have an urgent need for information about human behavior and function to create systems that take advantage of human capabilities, without overloading them. Because there is a large gap between what is known about human behavior and the information needed to predict pilot workload and performance in the complex missions projected for pilots of advanced helicopters, Army and NASA scientists are actively engaged in Human Factors Research at Ames. The research ranges from laboratory experiments to computational modeling, simulation evaluation, and inflight testing. Information obtained in highly controlled but simpler environments generates predictions which can be tested in more realistic situations. These results are used, in turn, to refine theoretical models, provide the focus for subsequent research, and ensure operational relevance, while maintaining predictive advantages. The advantages and disadvantages of each type of research are described along with examples of experimental results.

Hart, Sandra G.↗
NASA NTRS1988

Helicopter human factors

The state-of-the-art helicopter and its pilot are examined using the tools of human-factors analysis. The significant role of human error in helicopter accidents is discussed; the history of human-factors research on helicopters is briefly traced; the typical flight tasks are described; and the noise, vibration, and temperature conditions typical of modern military helicopters are characterized. Also considered are helicopter controls, cockpit instruments and displays, and the impact of cockpit design on pilot workload. Particular attention is given to possible advanced-technology improvements, such as control stabilization and augmentation, FBW and fly-by-light systems, multifunction displays, night-vision goggles, pilot night-vision systems, night-vision displays with superimposed symbols, target acquisition and designation systems, and aural displays. Diagrams, drawings, and photographs are provided.

Hart, Sandra G.↗
NASA NTRS1987

Research papers and publications (1981-1987): Workload research program

An annotated bibliography of the research reports written by participants in NASA's Workload Research Program since 1981 is presented, representing the results of theoretical and applied research conducted at Ames Research Center and at universities and industrial laboratories funded by the program. The major program elements included: 1) developing an understanding of the workload concept; 2) providing valid, reliable, and practical measures of workload; and 3) creating a computer model to predict workload. The goal is to provide workload-related design principles, measures, guidelines, and computational models. The research results are transferred to user groups by establishing close ties with manufacturers, civil and military operators of aerospace systems, and regulatory agencies; publishing scientific articles; participating in and sponsoring workshops and symposia; providing information, guidelines, and computer models; and contributing to the formulation of standards. In addition, the methods and theories developed have been applied to specific operational and design problems at the request of a number of industry and government agencies.

Hart, Sandra G.↗
NASA NTRS1987

Workshop on Workload and Training, and Examination of their Interactions: Executive summary

The goal of the workshop was to bring together experts in the fields of workload and training and representatives from the Dept. of Defense and industrial organizations who are reponsible for specifying, building, and managing advanced, complex systems. The challenging environments and requirements imposed by military helicopter missions and space station operations were presented as the focus for the panel discussions. The workshop permitted a detailed examination of the theoretical foundations of the fields of training and workload, as well as their practical applications. Furthermore, it created a forum where government, industry, and academic experts were able to examine each other's concepts, values, and goals. The discussions pointed out the necessity for a more efficient and effective flow of information among the groups respresented. The executive summary describes the rationale of the meeting, summarizes the primary points of discussion, and lists the participants and some of their summary comments.

Donchin, Emanuel↗
NASA NTRS1987

Measurement of pilot workload

A multistage process for evaluating the workload of a five-minute segment of flight including approach and landing for a typical transport aircraft was described. The goal of the analysis was to compare the workload of the two pilots. Four types of measurement techniques were suggested: Analytic (a preliminary task and time line analysis identified task requirements and target performance levels); Performance (flight path control, communications, and interval production); Physiological (heart rate and heart rate variability); and Subjective ratings (a multidimensional technique developed at NASA Ames).

Hart, Sandra G.↗
NASA NTRS1987

Inflight application of three pilot workload measurement techniques

Three inflight techniques for workload measurement were tested in nine pilots flying the NASA Kuiper Airborne Observatory: subjective ratings, heart rate, and communication performance. The activities that contributed to the crew-member workload varied; the commander was responsible for aircraft control and navigation whereas the copilot handled communications. The three workload measures were found to provide different information. Pilot ratings of workload, effort, and stress were sensitive to variations in flight-related task demands across flight segments but did not reflect specific differences in the type of demands imposed on the commander and the copilot. The heart rate was sensitive to the differential impact of duties, being higher for the commander than for the copilot. The rate of communications per minute of flight proved to be the most sensitive indicator. It was related to workload, stress, effort rating, and average heart rate across flight segments.

Hart, Sandra G.↗
NASA NTRS1987

The effects of display-control I/O, compatibility, and integrality on dual-task performance and subjective workload

The utility of speech technology was evaluated in terms of three dual task principles: resource competition between the time shared tasks, stimulus central processing response compatibility, and task integrality. Empirical support for these principles was reviewed. Two studies investigating the interactive effects of the three principles were described. Objective performance and subjective workload ratings for both single and dual tasks were examined. It was found that the single task measures were not necessarily good predictors for the dual task measures. It was shown that all three principles played an important role in determining an optimal task configuration. This was reflected in both the performance measures and the subjective measures. Therefore, consideration of all three principles is required to insure proper use of speech technology in a complex environment.

Tsang, Pamela S.↗
NASA NTRS1987

Decision support for workload assessment - Introducing WC FIELDE

Currently there is a great demand for mental workload evaluation in the course of system design and modification. In light of this demand, a microprocessor-based decision support system has been created called WC FIELDE: Workload Consultant for FIELD Evaluation. The system helps the user select workload measures appropriate to his or her application from the large pool of currently available techniques. Both novices and those with some workload experience may benefit from using WC FIELDE, since the system's operation is entirely transparent and all rules involved in the decision process are available for the user to examine. WC FIELDE recommends several assessment methodologies in decreasing order of appropriateness, and provides additional information on each measure at the end of the program in the form of text files.

Casper, Patricia A.↗
NASA NTRS1987

Step tracking shrinking targets

Four models describing how people might acquire targets that dynamically vary in size were examined; two that described movement speed as a simple function of target size (either initial or final) and two that described movement speed as a function of the predicted size of the targets at a fixed time in the future (one was referenced to the beginning of the reaction time phase, and the other to the end of this phase). It was found that movement time was best described as a function of a size prediction made at the end, rather than the start, of the reaction time phase. Subjective workload ratings primarily reflected the total amount of time needed to acquire the targets rather than the time pressure imposed by the diminishing size of these targets.

Johnson, Walter W.↗
NASA NTRS1987

Measuring pilot workload in a motion base simulator. III - Synchronous secondary task

This experiment continues earlier research of Kantowitz et al. (1983) conducted in a GAT-1 motion-base trainer to evaluate choice-reaction secondary tasks as measures of pilot work load. The earlier work used an asynchronous secondary task presented every 22 sec regardless of flying performance. The present experiment uses a synchronous task presented only when a critical event occurred on the flying task. Both two- and four-choice visual secondary tasks were investigated. Analysis of primary flying-task results showed no decrement in error for altitude, indicating that the key assumption necessary for using a choice secondary task was satisfied. Reaction times showed significant differences between 'easy' and 'hard' flight scenarios as well as the ability to discriminate among flight tasks.

Kantowitz, Barry H.↗
NASA NTRS1987

Inflight evaluation of pilot workload measures for rotorcraft research

The effectiveness of heart-rate monitoring and the NASA TLX workload rating scale (Hart et al., 1985) in measuring helicopter-pilot workloads is investigated experimentally. Four NASA test pilots flew two 2-h missions each in an SH-3G helicopter, following scenarios with takeoff, hover, cross-country, and landing tasks; pilot performance on the tasks undertaken near the landing area was measured by laser tracking. The results are presented in graphs and discussed in detail, and it is found that the TLX ratings clearly distinguish the flight segments and are well correlated with the performance data. The mean heart rate (measured as interbeat interval) is correlated (r = -0.69) with the TLX workload, but only the standard deviation of the interbeat interval is able to distinguish between flight segments; the correlation between standard deviation and TLX ratings is negative but not significant.

Shively, Robert J.↗
NASA NTRS1987

Measuring moment-to-moment pilot workload using synchronous presentations of secondary tasks in a motion-base trainer

A simulation was conducted to determine whether the sensitivity of secondary task measures of pilot workload could be improved by synchronizing their presentation to the occurrence of specific events or pilot actions. This synchronous method of presentation was compared to the more typical asynchronous method, where secondary task presentations are independent of pilot's flight-related activities. Twelve pilots flew low- and high-difficulty scenarios in a motion-base trainer with and without concurrent secondary tasks (e.g., choice reaction time and time production). The difficulty of each scenario was manipulated by the addition of 21 flight-related tasks superimposed on a standard approach and landing sequence. The insertion of the secondary tasks did not affect primary flight performance. However, secondary task performance did reflect workload differences between scenarios and among flight segments within scenarios, replicating the results of an earlier study in which the secondary tasks were presented asynchronously (Bortolussi et al., 1986).

Bortolussi, Michael R.↗
NASA NTRS1986

The relationship between workload and training - An introduction

This paper reviews the relationships among workload, performance, and training. Its goal is to introduce the concepts of workload and training and to suggest how they may be related. It suggests some of the practical and theoretical benefits to be derived from their joint consideration. Training effectiveness can be improved by monitoring trainee workload and the reliability of workload predictions, and measures can be improved by identifying and controlling the training levels of experimental subjects.

Hart, Sandra G.↗
NASA NTRS1986

Evaluating the subjective workload of directional orientation tasks with varying display formats

The impact of various flight-related tasks on the workload imposed by the requirement to compute new headings, course changes, and reciprocal headings is investigated experimentally. It is shown that, in terms of speed and accuracy, pilots are more efficient when alphanumeric display formats are provided. It is suggested that a voice command of 'turn to a specific heading' would provide the optimal method for issuing heading changes when used in conjunction with an alphanumeric display format.

Miller, Ronald C.↗
NASA NTRS1986

NASA Task Load Index (TLX): Computerized Version - Volume 1.0

This booklet and the accompanying diskette contain the materials necessary to collect subjective workload assessments with the NASA Task Load Index on IBM PC compatible microcomputers. This procedure for collecting workload ratings was developed by the Human Performance Group at NASA Ames Research Center during a three year research effort that involved more than 40 laboratory, simulation, and inflight experiments Although the technique is still undergoing evaluation, this package is being distributed to allow other researchers to use it in their own experiments Comments or suggestions about the procedure would be greatly appreciated This package is intended to fill a "nuts and bolts" function of describing the procedure. A bibliography provides background information about previous empirical findings and the logic that supports the procedure.

Hart, Sandra G.↗
NASA NTRS1986

NASA Task Load Index (TLX): Paper and Pencil Package - Volume 1.0

This booklet contains the materials necessary to collect subjective workload assessments with the NASA Task Load Index. This procedure for collecting workload ratings was developed by the Human Performance Group at NASA Ames Research Center during a three year research effort that involved more than 40 laboratory. simulation. and inflight experiments. Although the technique is still undergoing evaluation. this booklet is being distributed to allow other researchers to use it in their own experiments. Comments or suggestions about the procedure would be greatly appreciated. This package is intended to fill a "nuts and bolts" function of describing the procedure. A bibliography provides background information about previous empirical findings and the logic that supports the procedure.

Hart, Sandra G.↗