3,254 research outputs found

    Measurements of Pilot Time Delay as Influenced by Controller Characteristics and Vehicles Time Delays

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    A study to measure and compare pilot time delay when using a space shuttle rotational hand controller and a more conventional control stick was conducted at NASA Ames Research Center's Dryden Flight Research Facility. The space shuttle controller has a palm pivot in the pitch axis. The more conventional controller used was a general-purpose engineering simulator stick that has a pivot length between that of a typical aircraft center stick and a sidestick. Measurements of the pilot's effective time delay were obtained through a first-order, closed-loop, compensatory tracking task in pitch. The tasks were implemented through a space shuttle cockpit simulator and a critical task tester device. The study consisted of 450 data runs with four test pilots and one nonpilot, and used three control stick configurations and two system delays. Results showed that the heavier conventional stick had the lowest pilot effective time delays associated with it, whereas the shuttle and light conventional sticks each had similar higher pilot time delay characteristics. It was also determined that each control stick showed an increase in pilot time delay when the total system delay was increased

    Are sleep problems related to psychological distress in healthy aging during the covid-19 pandemic? A review

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    The SARS-CoV-2 pandemic, characterized by home confinement and other restrictive measures to reduce the spread of the infection, led to significant changes in people’s habits and lifestyle. One of the most common problems is the worsening of sleep quality or quantity, which could have negative effects on psychological wellbeing, particularly in older adults. The purposes of the present literature review considering healthy aging subjects are (a) to examine the existing research on sleep alterations during the current pandemic and (b) to highlight possible relationships between sleep problems and psychological distress. A systematic search strategy was implemented according to PRISMA guidelines in the international literature online databases, up to 1 July 2021. After identification and screening phases, 11 articles were included in this review. The studies found possible associations between sleep problems and mood changes—particularly in terms of depression and anxiety. In addition, altered sleep patterns seemed to be related to changes in individual aspects, lifestyle, and attitudes adopted by older adults during the COVID-19 lockdown. Thus, the pandemic could affect the sleep and psychological wellbeing of the older population, even in healthy aging

    Open loop small-signal control-to-output transfer function of PWM buck converter for CCM: modeling and measurements

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    Complete (k,3)-arcs from quartic curves

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    Complete (Formula presented.) -arcs in projective planes over finite fields are the geometric counterpart of linear non-extendible Near MDS codes of length (Formula presented.) and dimension (Formula presented.). A class of infinite families of complete (Formula presented.) -arcs in (Formula presented.) is constructed, for (Formula presented.) a power of an odd prime (Formula presented.). The order of magnitude of (Formula presented.) is smaller than (Formula presented.). This property significantly distinguishes the complete (Formula presented.) -arcs of this paper from the previously known infinite families, whose size differs from (Formula presented.) by at most (Formula presented.)

    Study of RPC gas mixtures for the ARGO-YBJ experiment

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    The ARGO-YBJ experiment consists of a RPC carpet to be operated at the Yangbajing laboratory (Tibet, P.R. China), 4300 m a.s.l., and devoted to the detection of showers initiated by photon primaries in the energy range 100 GeV - 20 TeV. The measurement technique, namely the timing on the shower front with a few tens of particles, requires RPC operation with 1 ns time resolution, low strip multiplicity, high efficiency and low single counting rate. We have tested RPCs with many gas mixtures, at sea level, in order to optimize these parameters. The results of this study are reported.Comment: 6 pages, 3 figures. To be published in Nucl. Instr. Meth. A, talk given at the "5th International Workshop on RPCs and Related Detectors", Bari (Italy) 199
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