13,354 research outputs found

    Research on display scanning, sampling, and reconstruction using separate main and secondary tracking tasks

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    Dynamic model for effects of random scanning and sampling on human operator tracking performanc

    A theory of human error

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    Human errors tend to be treated in terms of clinical and anecdotal descriptions, from which remedial measures are difficult to derive. Correction of the sources of human error requires an attempt to reconstruct underlying and contributing causes of error from the circumstantial causes cited in official investigative reports. A comprehensive analytical theory of the cause-effect relationships governing propagation of human error is indispensable to a reconstruction of the underlying and contributing causes. A validated analytical theory of the input-output behavior of human operators involving manual control, communication, supervisory, and monitoring tasks which are relevant to aviation, maritime, automotive, and process control operations is highlighted. This theory of behavior, both appropriate and inappropriate, provides an insightful basis for investigating, classifying, and quantifying the needed cause-effect relationships governing propagation of human error

    Search for Variable Stars in the Globular Cluster M3

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    We describe here results of a photometric time-sequence survey of the globular cluster M3 (NGC 5272), in a search for contact and detached eclipsing binary stars. We have discovered only one likely eclipsing binary and one SX Phe type star in spite of monitoring 4077 stars with V<20.0V<20.0 and observing 25 blue stragglers. The newly identified SX Phe star, V237, shows a light curve with a variable amplitude. Variable V238 shows variability either with a period of 0.49 d or with a period of 0.25 d. On the cluster colour-magnitude diagram, the variable occupies a position a few hundredths of magnitude to the blue of the base of the red giant branch. V238 is a likely descendent of a binary blue straggler. As a side result we obtained high quality data for 42 of the previously known RR Lyrae variables, including 33 of Bailey type ab, 7 type c and 2 double-mode pulsators. We used equations that relate the physical properties of RRc stars to their pulsation periods and Fourier parameters to derive masses, luminosities, temperatures and helium parameters for five of the RRc stars. One of the RRd stars (V79) has switched modes. In previous studies, it was classified as RRab, but our observations show that it is an RRd star with the first overtone mode dominating. This indicates blueward evolution on the horizontal branch.Comment: 21 pages including 14 figures, Latex, requires mn.sty, psfig.sty. Submitted, MNRA

    Measurements of the extinction parameters of hot seeded hydrogen at high pressures

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    Measurement of extinction parameter of tungsten-hydrogen aerosols as function of wavelength at high pressures and temperature

    Technical approaches for measurement of human errors

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    Human error is a significant contributing factor in a very high proportion of civil transport, general aviation, and rotorcraft accidents. The technical details of a variety of proven approaches for the measurement of human errors in the context of the national airspace system are presented. Unobtrusive measurements suitable for cockpit operations and procedures in part of full mission simulation are emphasized. Procedure, system performance, and human operator centered measurements are discussed as they apply to the manual control, communication, supervisory, and monitoring tasks which are relevant to aviation operations

    Analysis of pilot control strategy

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    Methods for nonintrusive identification of pilot control strategy and task execution dynamics are presented along with examples based on flight data. The specific analysis technique is Nonintrusive Parameter Identification Procedure (NIPIP), which is described in a companion user's guide (NASA CR-170398). Quantification of pilot control strategy and task execution dynamics is discussed in general terms followed by a more detailed description of how NIPIP can be applied. The examples are based on flight data obtained from the NASA F-8 digital fly by wire airplane. These examples involve various piloting tasks and control axes as well as a demonstration of how the dynamics of the aircraft itself are identified using NIPIP. Application of NIPIP to the AFTI/F-16 flight test program is discussed. Recommendations are made for flight test applications in general and refinement of NIPIP to include interactive computer graphics

    Mission-oriented requirements for updating MIL-H-8501. Volume 2: STI background and rationale

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    A supplement to the structure of a new flying and ground handling qualities specification for military rotorcraft structure is presented in order to explain the background and rationale for the specification structure, the proposed forms of criteria, and the status of the existing data base. Critical gaps in the data base for the new structure are defined, and recommendations are provided for the research required to address the most important of these gaps

    Functional requirements for the man-vehicle systems research facility

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    The NASA Ames Research Center proposed a man-vehicle systems research facility to support flight simulation studies which are needed for identifying and correcting the sources of human error associated with current and future air carrier operations. The organization of research facility is reviewed and functional requirements and related priorities for the facility are recommended based on a review of potentially critical operational scenarios. Requirements are included for the experimenter's simulation control and data acquisition functions, as well as for the visual field, motion, sound, computation, crew station, and intercommunications subsystems. The related issues of functional fidelity and level of simulation are addressed, and specific criteria for quantitative assessment of various aspects of fidelity are offered. Recommendations for facility integration, checkout, and staffing are included

    Mission-oriented requirements for updating MIL-H-8501. Volume 1: STI proposed structure

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    The structure of a new flying and ground handling qualities specification for military rotorcraft is presented. This preliminary specification structure is intended to evolve into a replacement for specification MIL-H-8501A. The new structure is designed to accommodate a variety of rotorcraft types, mission flight phases, flight envelopes, and flight environmental characteristics and to provide criteria for three levels of flying qualities, a systematic treatment of failures and reliability, both conventional and multiaxis controllers, and external vision aids which may also incorporate synthetic display content. Existing and new criteria were incorporated into the new structure wherever they could be substantiated

    The Reaction 7Li(pi+,pi-)7B and its Implications for 7B

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    The reaction 7Li(pi+,pi-)7B has been measured at incident pion energies of 30-90 MeV. 7Li constitutes the lightest target nucleus, where the pionic charge exchange may proceed as a binary reaction to a discrete final state. Like in the Delta-resonance region the observed cross sections are much smaller than expected from the systematics found for heavier nuclei. In analogy to the neutron halo case of 11Li this cross section suppression is interpreted as evidence for a proton halo in the particle-unstable nucleus 7B.Comment: 4 pages, 4 figure
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