Interpretation of cosmic ray composition: The pathlength distribution
For abstract see A81-43868.
Protheroe, R. J.↗
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Results for “Comstock”
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Oculometric indices of simulator and aircraft motion
The effects on eye scan behavior of both simulator and aircraft motion and sensitivity of an oculometric measure to motion effects was demonstrated. It was found that fixation time is sensitive to motion effects. Differences between simulator motion and no motion conditions during a series of simulated ILS approaches were studied. The mean fixation time for the no motion condition was found to be significantly longer than for the motion conditions. Eye scan parameters based on data collected in flight, and in fixed base simulation were investigated. Motion effects were evident when the subject was viewing a display supplying attitude and flight path information. The nature of the information provided by motion was examined. The mean fixation times for the no motion condition were significantly longer than for either motion condition, while the two motion conditions did not differ. It is shown that motion serves an alerting function, providing a cue or clue to the pilot that something happened. It is suggested that simulation without motion cues may represent an understatement of the true capacity of the pilot.
Comstock, J. R.↗
Visual information transfer. 1: Assessment of specific information needs. 2: The effects of degraded motion feedback. 3: Parameters of appropriate instrument scanning behavior
Pilot and flight crew assessment of visually displayed information is examined as well as the effects of degraded and uncorrected motion feedback, and instrument scanning efficiency by the pilot. Computerized flight simulation and appropriate physiological measurements are used to collect data for standardization.
Comstock, J. R., Jr.↗
Flight versus simulator scan behavior
It is pointed out that most of the modern flight simulators used for pilot training have included expensive motion bases, while the quantitative justification for motion is lacking. The present investigation is concerned with the effects of flight versus simulator conditions on scan behavior as a function of control mode and the presence or absence of traffic on the map display. Matching tests conducted in flight and in a fixed-base simulator permitted an evaluation of the differences in scanning behavior in the real world (flight) and in the 'less real' world (simulator). Scanning behavior in flight was found to be significantly different from the simulator. In flight, the dwell percentage increased on the Electronic Attitude Direction Indicator (EADI), and decreased on the Electronic Horizontal Situation Indicator (EHSI). The average dwell time on all instruments decreased in flight.
Spady, A. A., Jr.↗
Visual information transfer. Part 1: Assessment of specific information needs. Part 2: Parameters of appropriate instrument scanning behavior
The present study explored eye scan behavior as a function of level of subject training. Oculometric (eye scan) measures were recorded from each of ten subjects during training trials on a CRT based flight simulation task. The task developed for the study incorporated subtasks representative of specific activities performed by pilots, but which could be performed at asymptotic levels within relatively short periods of training. Changes in eye scan behavior were examined as initially untrained subjects developed skill in the task. Eye scan predictors of performance on the task were found. Examination of eye scan in proximity to selected task events revealed differences in the distribution of looks at the instruments as a function of level of training.
Comstock, J. R., Jr.↗
The effects of simulator and aircraft motion on eye scan behavior
In a series of three experiments on the effects on eye-scan behavior of both simuator and aircraft motion, the sensitivity of an oculometric measure to motion effects was demonstrated. 'Fixation time', defined as the time the eyes spend at a particular location before moving on (saccade) to another fixation point, was found to be sensitive to motion effects in each of the experiments conducted. The results of the present study support the hypothesis that motion serves an alerting function, providing a 'cue' or 'clue' to the pilot that 'something happened'. The results do not support the hypothesis that direction of motion is conveyed through the type of motion information employed in these experiments.
Comstock, J. R., Jr.↗
Eye-scan behavior in a flight simulation task as a function of level of training
The present study explored eye-scan behavior as a function of level of subject training. Oculometric (eye-scan) measures were recorded from each of ten subjects during training trials on a CRT-based flight simulation task. The task developed for the study incorporated subtasks representative of specific activities performed by pilots, but which could be performed at asymptotic levels within relatively short periods of training. Changes in eye-scan behavior were examined as initially untrained subjects developed skill in the task. Eye-scan predictors of performance on the task were found. Examination of eye-scan in proximity to selected task events revealed differences in the distribution of looks at the instruments as a function of level of training.
Comstock, J. R., Jr.↗
Mental-State Estimation, 1987
Reports on the measurement and evaluation of the physiological and mental state of operators are presented.
Comstock, J. Raymond, Jr.↗
Time-locked time-histories - A new way of examining eye-movement data
A problem often encountered when eye-movement measurement is conducted is the choice of 'indices' or 'statistics' available to present such information. The present study reports the use of the Time-Locked Time-History as a technique of value in the examination and presentation of eye-movement data. Plots created using this technique are labeled time-locked time-histories as they illustrate subject eye lookpoint during a period of time before and after a certain time-locking event. Events that occur with some degree of repetition, such as the onset or termination of control activities, warning signals, or changes in indicator positions may be utilized as time-locking events. The present study reports the use of this technique in an eye-movement study using a secondary task in which the subject must discriminate specific types of information in the display.
Comstock, J. Raymond, Jr.↗
Physiological assessment of task underload
The ultimate goal of research efforts directed at underload, boredom, or complacency in high-technology work environments is to detect conditions or states of the operator that can be demonstrated to lead to performance degradation, and then to intervene in the environment to restore acceptable system performance. Physiological measures may provide indices of changes in condition or state of the operator that may be of value in high-technology work environments. The focus of the present study was on the use of physiological measures in the assessment of operator condition or state in a task underload scenario. A fault acknowledgement task characterized by simple repetitive responses with minimal novelty, complexity, and uncertainty was employed to place subjects in a task underload situation. Physiological measures (electrocardiogram (ECG), electroencephalogram (EEG), and pupil diameter) were monitored during task performance over a one-hour test session for 12 subjects. Each of the physiological measures exhibited changes over the test session indicative of decrements in subject arousal level. While high correlations between physiological measures were found across subjects, individual differences between subjects support the use of profiling techniques to establish baselines unique to each subject.
Comstock, J. Raymond, Jr.↗
Usefulness of heart measures in flight simulation
The results of three studies performed at the NASA Langley Research Center are presented to indicate the areas in which heart measures are useful for detecting differences in the workload state of subjects. Tasks that involve the arousal of the sympathetic nervous system, such as landing approaches, were excellent candidates for the use of average heart-rate and/or the increase in heart-rate during a task. The latter of these two measures was the better parameter because it removed the effects of diurnal variations in heart-rate and some of the intersubject variability. Tasks which differ in the amount of mental resources required are excellent candidates for heart-rate variability measures. Heart-rate variability measures based upon power spectral density techniques were responsive to the changing task demands of landing approach tasks, approach guidance options, and 2 versus 20 second interstimulus-intervals of a monitoring task. Heart-rate variability measures were especially sensitive to time-on-task when the task was characterized by minimal novelty, complexity, and uncertainty (i.e., heart-rate variability increases as a function of the subjects boredom).
Harris, Randall L., Sr.↗
A comparison of transportation node costs and their primary drivers
This paper describes the process for defining and evaluating the costs of alternative transportation node concepts for Space Station Freedom. A cost estimating methodology including costs of development, production, delivery, assembly, steady state operations, and mission-specific operations is described in detail. The primary drivers of transportation node costs are identified and discussed.
Comstock, Douglas A.↗
Memory implications of the spin-value effect in soft multilayers
New multilayer permalloy materials with thin separation layers that have significantly increased M-R coefficients at room temperature have the potential for substantially increasing both the speed and density of M-R memories. An analysis in the following discussion shows that the bit density at a given performance level is related to the product of M-R response and sheet resistivity when operating at the current-density limit. With a doubling of both sheet resistivity and M-R response over existing materials, the bit area can be reduced by about a factor of 4. Alternatively, if the bit area is kept the same, signal output is increased by a factor of 4 and circuit time constants can be reduced by a factor of 16.
Pohm, A. V.↗
Demagnetization effects on forward and reverse thresholds of M-R memory elements
A refinement in the way hard-axis demagnetizing effects are treated in multilayer M-R memory elements brings experimental and calculated results into agreement for both the forward and reverse switching thresholds. In the improved model, the nonuniform rotation of the magnetization in the elements because of edge pinning is taken into account. The demagnetizing fields are treated as corrections to the hard-axis word field rather than an addition to the anisotropy constant.
Pohm, A. V.↗
The multi-attribute task battery for human operator workload and strategic behavior research
The Multi-Attribute Task (MAT) Battery provides a benchmark set of tasks for use in a wide range of lab studies of operator performance and workload. The battery incorporates tasks analogous to activities that aircraft crewmembers perform in flight, while providing a high degree of experimenter control, performance data on each subtask, and freedom to use nonpilot test subjects. Features not found in existing computer based tasks include an auditory communication task (to simulate Air Traffic Control communication), a resource management task permitting many avenues or strategies of maintaining target performance, a scheduling window which gives the operator information about future task demands, and the option of manual or automated control of tasks. Performance data are generated for each subtask. In addition, the task battery may be paused and onscreen workload rating scales presented to the subject. The MAT Battery requires a desktop computer with color graphics. The communication task requires a serial link to a second desktop computer with a voice synthesizer or digitizer card.
Comstock, J. Raymond, Jr.↗
An initial test of a normative Figure Of Merit for the quality of overall task performance
An overall indicator, or Figure Of Merit (FOM), of the quality of crew/vehicle system performance is needed to establish the effect of workload on efficiency and to identify overload conditions. A normative FOM is proposed in which performance is measured on a representative task and a normative data base obtained. FOMs for subsequent executions of the task are then reported in terms of weighted deviations from average task performance. Performance of discrete tasks is measured primarily in terms of subtask time and errors. Discrete task performance is then combined with a measure of continuous vehicle control. In order to test the normative FOM procedure, the technique was applied to an existing set of data from a simulated landing task in which standard communications with ATC was compared with a data link communications system. The results indicated that while mean task performance was not affected, task variability, as measured by the FOM, was significantly higher when data link communications were used. In order to establish the sensitivity of the normative FOM method, further testing of the measure is recommended.
Lemay, Moira↗
Multi-Attribute Task Battery - Applications in pilot workload and strategic behavior research
The Multi-Attribute Task (MAT) Battery provides a benchmark set of tasks for use in a wide range of lab studies of operator performance and workload. The battery incorporates tasks analogous to activities that aircraft crewmembers perform in flight, while providing a high degree of experimenter control, performance data on each subtask, and freedom to nonpilot test subjects. Features not found in existing computer based tasks include an auditory communication task (to simulate Air Traffic Control communication), a resource management task permitting many avenues or strategies of maintaining target performance, a scheduling window which gives the operator information about future task demands, and the option of manual or automated control of tasks. Performance data are generated for each subtask. In addition, the task battery may be paused and onscreen workload rating scales presented to the subject. The MAT Battery requires a desktop computer with color graphics. The communication task requires a serial link to a second desktop computer with a voice synthesizer or digitizer card.
Arnegard, Ruth J.↗
Program For Workload And Performance Experiments
Multi-Attribute Task (MAT) battery of computer programs gives researcher capability of performing experiments in multitask workloads and performances. Provides benchmark set of tasks for use in wide range of laboratory studies of operator performance and workload. Incorporates tasks analogous to activities aircraft crewmembers perform in flight, while providing high degree of experiment control, performance data on each subtask, and freedom to use nonpilot test subjects. Designed to use serially linked second computer to generate voice messages for communication task. Also used independently of voice computer if no computer-synthesized voice messages desired or if some other method of presenting auditory messages devised. Written in QuickBasic and Assembly language for IBM PC(R) series.
Comstock, J. Raymond, Jr.↗