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At least 919 records · Page 51
All sourcesNASA NTRSDOE OSTI
NASA NTRS1973

ERIM progress report on use of ERTS-1 data: Summary report of work on ten tasks

The author has identified the following significant results. Several of the tasks have produced significant results which are summarized: (1) Absolute water depth can be calculated from a ratio of signals from bands MSS 4 and MSS 5. (2) A 13 category terrain feature classification map of Yellowstone National Park has been produced using supervised pattern recognition techniques. (3) ERTS-1 data has been shown to provide a detection and monitoring capability for a number of water quality problems associated with off-shore ocean dumping sites and inland lakes. (4) A corrected ratio of bands MSS-5 and MSS-7 signals has been formed. (5) A concise format has been devised for storing the ratio signatures of geologic rock and mineral materials determined from laboratory reflectance spectra. (6) Results of work in information extraction demonstrate: signal variability exists among ERTS-1 detectors in any one spectral band that will impact users doing quantitative analysis on successive ERTS-1 images; a newly developed computer-aided procedure for correlating ERTS-1 pixels to ground features; the strong influence of atmospheric effects in ERTS-1 data; and area estimation accuracies are better using the ERIM proportion estimation algorithm than for conventional recognition techniques.

Thomson, F. J.↗
NASA NTRS1973

Life science payload definition and integration study, task C and D. Volume 3: Appendices

Research equipment requirements were based on the Mini-7 and Mini-30 laboratory concepts defined in Tasks A and B of the intial LSPD contract. Modified versions of these laboratories and the research equipment within them were to be used in three missions of Shuttle/Sortie Module. These were designated (1) the shared 7-day laboratory (a mission with the life sciences laboratory sharing the sortie module with another scientific laboratory), (2) the dedicated 7-day laboratory (full use of the sortie module), and (3) the dedicated 30-day laboratory (full sortie module use with a 30-day mission duration). In defining the research equipment requirements of these laboratories, the equipment was grouped according to its function, and equipment unit data packages were prepared.

Source record↗
NASA NTRS1972

The employment of a spoken language computer applied to an air traffic control task.

Assessment of the merits of a limited spoken language (56 words) computer in a simulated air traffic control (ATC) task. An airport zone approximately 60 miles in diameter with a traffic flow simulation ranging from single-engine to commercial jet aircraft provided the workload for the controllers. This research determined that, under the circumstances of the experiments carried out, the use of a spoken-language computer would not improve the controller performance.

Laveson, J. I.↗
NASA NTRS1973

A model of the human in a cognitive prediction task.

The human decision maker's behavior when predicting future states of discrete linear dynamic systems driven by zero-mean Gaussian processes is modeled. The task is on a slow enough time scale that physiological constraints are insignificant compared with cognitive limitations. The model is basically a linear regression system identifier with a limited memory and noisy observations. Experimental data are presented and compared to the model.

Rouse, W. B.↗
NASA NTRS1973

Task three: Report: STDN Antenna and preamplifier cost tradeoff study

The general goal of this task, STDN Antenna and Preamplifier G/T Study, was to determine cost-effective combinations of antennas and preamplifiers for several sets of conditions for frequency, antenna elevation angle, and rain. The output of the study includes design curves and tables which indicate the best choice of antenna size and preamplifier type to provide a given G/T performance. The report indicates how to evaluate the cost effectiveness of proposed improvements to a given station. Certain parametric variations are presented to emphasize the improvement available by reducing RF losses and improving the antenna feed.

Source record↗
NASA NTRS1973

Task six report: Spacecraft communication terminal evaluation

An analytical comparison is made of space communication accomplished at six different wavelengths. In the radio band, 2.25, 7.5, and 14.5 GHz systems are analyzed, while at optical wavelengths, 0.53, 1.06 and 10.6 micron systems are examined. The purpose of the comparison is to determine which of these systems will require the least hardware weight to perform a given communication task. The problem is solved by requiring each communication system to meet a given performance while selecting combinations of transmitted power and antenna diameter to obtain the least overall system weight. This performance is provided while maintaining practical values for parameters other than antenna diameter and power, which also affect system performance. The results of the analysis indicate that for future data links over ranges of 42,000 to 84,000 km and with data bandwidths of 100 to 1000 MHz, the CO2 laser system will provide the required performance with the least total system weight impact on a spacecraft.

Source record↗
NASA NTRS1970

Space shuttle vehicle rocket plume impingement study for separation analysis. Tasks 2 and 3: Definition and preliminary plume impingement analysis for the MSC booster

The results are presented of a space shuttle plume impingement study for the Manned Spacecraft Center configuration. This study was conducted as two tasks which were to (1) define the orbiter main stage engine exhaust plume flow field, and (2) define the plume impingement heating, force and resulting moment environments on the booster during the staging maneuver. To adequately define these environments during the staging maneuver and allow for deviation from the nominal separation trajectory, a multitude of relative orbiter/booster positions are analyzed which map the region that contains the separation trajectories. The data presented can be used to determine a separation trajectory which will result in acceptable impingement heating rates, forces, and the resulting moments. The data, presented in graphical form, include the effect of roll, pitch and yaw maneuvers for the booster. Quasi-steady state analysis methods were used with the orbiter engine operating at full thrust. To obtain partial thrust results, simple ratio equations are presented.

Wojciechowski, C. J.↗
NASA NTRS1974

Power spectral density analysis of the electromyogram from a work task performed in a full pressure suit

Surface electromyograms (EMG) taken from three upper torso muscles during a push-pull task were analyzed by a power spectral density technique to determine the utility of the spectral analysis for identifying changes in the EMG caused by muscular fatigue. The results confirmed the value of the frequency analysis for identifying fatigue producing muscular performance. Data revealed reliable differences between muscles in fatigue induced responses to various locations in the reach envelope at which the subjects were required to perform the push-pull exercise, and the differential sensitivity of individual muscles to the various reach positions; i.e., certain reach positions imposed more fatigue related shifts in EMG power than did others. It was found that a pressurized space suit changed the pattern of normal shirtsleeve muscle fatigue responses in all three of the muscles.

Lafevers, E. V.↗
NASA NTRS1974

Vertex evoked potentials in a rating-scale detection task: Relation to signal probability

Vertex evoked potentials were recorded from human subjects performing in an auditory detection task with rating scale responses. Three values of a priori probability of signal presentation were tested. The amplitudes of the N1 and P3 components of the vertex potential associated with correct detections of the signal were found to be systematically related to the strictness of the response criterion and independent of variations in a priori signal probability. No similar evoked potential components were found associated with signal absent judgements (misses and correct rejections) regardless of the confidence level of the judgement or signal probability. These results strongly support the contention that the form of the vertex evoked response is closely correlated with the subject's psychophysical decision regarding the presence or absence of a threshold level signal.

Squires, K. C.↗
NASA NTRS1973

A tactual pilot aid for the approach-and-landing task: Inflight studies

A pilot aid -- a kinesthetic-tactual compensatory display -- for assisting novice pilots in various inflight situations has undergone preliminary inflight testing. The efficacy of this display, as compared with two types of visual displays, was evaluated in both a highly structured approach-and-landing task and a less structured test involving tight turns about a point. In both situations, the displayed quantity was the deviation (alpha sub 0 - alpha) in angle at attack from a desired value alpha sub 0. In the former, the performance with the tactual display was comparable with that obtained using a visual display of (alpha sub 0 - alpha), while in the later, substantial improvements (reduced tracking error (55%), decreased maximum altitude variations (67%), and decreased speed variations (43%)), were obtained using the tactual display. It appears that such a display offers considerable potential for inflight use.

Gilson, R. D.↗
NASA NTRS1975

Feasibility study of modern airships, phase 1. Volume 3: Historical overview (task 1)

The history of lighter-than-air vehicles is reviewed in terms of providing a background for the mission analysis and parametric analysis tasks. Data from past airships and airship operations are presented in the following areas: (1) parameterization of design characteristics; (2) markets, missions, costs, and operating procedures, (3) indices of efficiency for comparison; (4) identification of critical design and operational characteristics; and (5) definition of the 1930 state-of-the-art and the 1974 state-of-the-art from a technical and economic standpoint.

Faurote, G. L.↗
NASA NTRS1975

Detection of system failures in multi-axes tasks

The effects of the pilot's participation mode in the control task on his workload level and failure detection performance were examined considering a low visibility landing approach. It is found that the participation mode had a strong effect on the pilot's workload, the induced workload being lowest when the pilot acted as a monitoring element during a coupled approach and highest when the pilot was an active element in the control loop. The effects of workload and participation mode on failure detection were separated. The participation mode was shown to have a dominant effect on the failure detection performance, with a failure in a monitored (coupled) axis being detected significantly faster than a comparable failure in a manually controlled axis.

Ephrath, A. R.↗
NASA NTRS1975

Human performance evaluation in dual-axis critical task tracking

A dual axis tracking using a multiloop critical task was set up to evaluate human performance. The effects of control stick variation and display formats are evaluated. A secondary loading was used to measure the degradation in tracking performance.

Ritchie, M. L.↗
NASA NTRS1975

Decision-related cortical potentials during an auditory signal detection task with cued observation intervals

Cortical-evoked potentials were recorded from human subjects performing an auditory detection task with confidence rating responses. Unlike earlier studies that used similar procedures, the observation interval during which the auditory signal could occur was clearly marked by a visual cue light. By precisely defining the observation interval and, hence, synchronizing all perceptual decisions to the evoked potential averaging epoch, it was possible to demonstrate that high-confidence false alarms are accompanied by late-positive P3 components equivalent to those for equally confident hits. Moreover the hit and false alarm evoked potentials were found to covary similarly with variations in confidence rating and to have similar amplitude distributions over the scalp. In a second experiment, it was demonstrated that correct rejections can be associated with a P3 component larger than that for hits. Thus it was possible to show, within the signal detection paradigm, how the two major factors of decision confidence and expectancy are reflected in the P3 component of the cortical-evoked potential.

Squires, K. C.↗
NASA NTRS1975

Crop Identification Technolgy Assessment for Remote Sensing (CITARS). Volume 1: Task design plan

A plan for quantifying the crop identification performances resulting from the remote identification of corn, soybeans, and wheat is described. Steps for the conversion of multispectral data tapes to classification results are specified. The crop identification performances resulting from the use of several basic types of automatic data processing techniques are compared and examined for significant differences. The techniques are evaluated also for changes in geographic location, time of the year, management practices, and other physical factors. The results of the Crop Identification Technology Assessment for Remote Sensing task will be applied extensively in the Large Area Crop Inventory Experiment.

Hall, F. G.↗
NASA NTRS1976

Biomedical applications engineering tasks

The engineering tasks performed in response to needs articulated by clinicians are described. Initial contacts were made with these clinician-technology requestors by the Southwest Research Institute NASA Biomedical Applications Team. The basic purpose of the program was to effectively transfer aerospace technology into functional hardware to solve real biomedical problems.

Laenger, C. J., Sr.↗
NASA NTRS1976

Design document for shuttle task 501. Shuttle carrier aircraft transceiver console (SED 36115353-301)

The flight data for the space shuttle orbiter (SSO) is transmitted via S band to a transceiver in the shuttle carrier aircraft (SCA) for relay to the ground during the mated portion of the approach and landing test (ALT). The transceiver is mounted in the SCA transceiver console for shuttle task 501 testing. This document defines the requirements for the SCA transceiver console, the design description, test plan for the console prior to installating the spacecraft equipment in the console, and the test plan for acceptance tests.

Doland, G. D.↗
NASA NTRS1976

Psychological and physiological correlates of stress: Performance on a cooperative task

The relationship of personality dimensions to performance was investigated. The personality measure used to select subjects, the Barratt impulsiveness scale, is hypothesized to be related to a style of behavior which should affect the trend of choices which various subjects will make. Personality dimensions were specifically examined during performance of a cooperative task, the Prisoner's Dilemma.

Roessler, R.↗