91,991 research outputs found

    ATS-6 millimeter wavelength propagation experiment

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    The fixed 20/30 GHz ground terminal is described in detail; it is being used for path diversity measurements in the ATS-6 millimeter wavelength propagation experiment. The current status and summary of operations are reviewed

    CTS/Comstar communications link characterization experiment

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    Measurements of angle of arrival and amplitude fluctuations on millimeter wavelength Earth-space communication links are described. Measurement of rainfall attenuation and radiometric temperature statistics and the assessment of the performance of a self-phased array as a receive antenna on an Earth-space link are also included

    Simple and robust rules for monetary policy

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    This paper focuses on simple normative rules for monetary policy which central banks can use to guide their interest rate decisions. Such rules were first derived from research on empirical monetary models with rational expectations and sticky prices built in the 1970s and 1980s. During the past two decades substantial progress has been made in establishing that such rules are robust. They perform well with a variety of newer and more rigorous models and policy evaluation methods. Simple rules are also frequently more robust than fully optimal rules. Important progress has also been made in understanding how to adjust simple rules to deal with measurement error and expectations. Moreover, historical experience has shown that simple rules can work well in the real world in that macroeconomic performance has been better when central bank decisions were described by such rules. The recent financial crisis has not changed these conclusions, but it has stimulated important research on how policy rules should deal with asset bubbles and the zero bound on interest rates. Going forward the crisis has drawn attention to the importance of research on international monetary issues and on the implications of discretionary deviations from policy rules.Monetary policy

    Heat-transfer and pressure measurements on a simulated elevon deflected 30 deg near flight conditions at Mach 7

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    Heat transfer rates and pressures were obtained on an elevon plate (deflected 30 deg) and a flat plate upstream of the elevon in an 8 foot high-temperature structures tunnel. The flight Reynolds number and flight total enthalpy for altitudes of 26.8 km and 28.7 km at Mach seven were duplicated. The heat transfer and pressure data were used to establish heating and pressure loads. The measured heating was compared with several theoretical predictions, and the closest agreement obtained with a Schultz-Grunow reference enthalpy method of calculation

    Extreme sea water temperatures and densities along the North Atlantic States during summer 1955

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    During the summer of 1955, record high sea water temperatures were observed in harbors and coastal waters of the North Atlantic States. Record air temperatures also occurred during this period. It is concluded that high sea water temperatures were due in large part to continued high air temperatures. The record low densities (or salinities) during the same summer corresponded with the periods of hurricanes Connie and Diane, hence the high runoff following these storms was doubtless responsible. The lag between rainfall and noticeable dilution and the delay in return to normalcy depend upon several factors· including the amount of rain, type of estuary, and size of drainage basin

    ATS-6 millimeter wavelength propagation experiment

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    The Ohio State University participation in the ATS-6 Millimeter Wavelength Propagation Experiment is summarized. Attenuation was measured simultaneously at 20 and 30 GHz on earth space propagation paths to two ground terminals located at Columbus, Ohio. In addition, 20 and 30 GHz radiometric temperatures were measured along the same propagation paths; and the 20 GHz radiometric temperature was also measured at a third ground terminal. The results of these measurements are presented, and diversity gains for the four pairs of propagation paths are discussed. The scintillation characteristics of the received signals are also presented
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