3,609 research outputs found

    Pilot workload and fatigue: A critical survey of concepts and assessment techniques

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    The principal unresolved issues in conceptualizing and measuring pilot workload and fatigue are discussed. These issues are seen as limiting the development of more useful working concepts and techniques and their application to systems engineering and management activities. A conceptual analysis of pilot workload and fatigue, an overview and critique of approaches to the assessment of these phenomena, and a discussion of current trends in the management of unwanted workload and fatigue effects are presented. Refinements and innovations in assessment methods are recommended for enhancing the practical significance of workload and fatigue studies

    Study of flight management requirements during SST low visibility approach and landing operations Final summary report

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    Flight management operational problems and task requirements for low visibility approach and landing of supersonic transport

    Simulator evaluation of display concepts for pilot monitoring and control of space shuttle approach and landing. Phase 2: Manual flight control

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    A study of the display requirements for final approach management of the space shuttle orbiter vehicle is presented. An experimental display concept, providing a more direct, pictorial representation of the vehicle's movement relative to the selected approach path and aiming points, was developed and assessed as an aid to manual flight path control. Both head-up, windshield projections and head-down, panel mounted presentations of the experimental display were evaluated in a series of simulated orbiter approach sequence. Data obtained indicate that the experimental display would enable orbiter pilots to exercise greater flexibility in implementing alternative final approach control strategies. Touchdown position and airspeed dispersion criteria were satisfied on 91 percent of the approach sequences, representing various profile and wind effect conditions. Flight path control and airspeed management satisfied operationally-relevant criteria for the two-segment, power-off orbiter approach and were consistently more accurate and less variable when the full set of experimental display elements was available to the pilot. Approach control tended to be more precise when the head-up display was used; however, the data also indicate that the head-down display would provide adequate support for the manual control task

    Towards a hardware implementation of ultra-wideband beamforming

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    Factors Influencing Utilization of Air Cargo Containerization in the United States Air Force

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    As the Department of Defense budget continues to decrease, the growing requirement to meet national strategic mobility objectives with limited resources provides a major impetus for cost effective and credible transportation innovations. The commercial transportation industry has increasingly accepted cargo containerization as a method to take advantage of intermodal shipping efficiency and cost savings. The military implementation of these same shipping initiatives must be flexible, reliable, and compatible with the existing cargo handling systems already designed to deliver fighting forces to conflicts throughout the world. This thesis examines cost and container utilization factors among units familiar with the ISU bins provided by AAR Cadillac Manufacturing. The objective is to evaluate the costs and factors experienced by the responsible units in the procurement, maintenance, and operation of these air cargo containerization systems. The research results indicate that the Life cycle cost of containerization may be greater than the comparable costs of the current 463L palletization system. However, these units indicated several potential advantages to air cargo containerization implementation including: reduced contents damage, pilferage, and pre-clearance requirements; improved system reliability and cargo tracking capability; and better system operations

    Relaxation properties of the quantum kinetics of carrier-LO-phonon interaction in quantum wells and quantum dots

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    The time evolution of optically excited carriers in semiconductor quantum wells and quantum dots is analyzed for their interaction with LO-phonons. Both the full two-time Green's function formalism and the one-time approximation provided by the generalized Kadanoff-Baym ansatz are considered, in order to compare their description of relaxation processes. It is shown that the two-time quantum kinetics leads to thermalization in all the examined cases, which is not the case for the one-time approach in the intermediate-coupling regime, even though it provides convergence to a steady state. The thermalization criterion used is the Kubo-Martin-Schwinger condition.Comment: 7 pages, 8 figures, accepted for publication in Phys. Rev.

    A simulator study of flight management task performance during low visibility approach and landing using baseline category 2 flight instrumentation

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    Simulator study of flight management task performance during low visibility approach and landing using baseline category 2 flight instrumentatio
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