55,178 research outputs found

    A Method for Establishing Outdoor Recreation Project Priorities in Alaska

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    The authors thank Theodore Smith, Edward Kramer and Nat Goodhue of the Division of Parks for information and comments supplied during this study, and Frank Orth, Charles Marsh, Ed Kramer, C.E. Logsdon, and Frank Wooding for reviewing the manuscript. Thanks is also due the Department of Business Administration, University of Alaska, Fairbanks, Dale Swanson, Head, for their cooperation in this research project.The objectives of this study are to define outdoor recreation benefits to the public and to develop a priority ranking method for proposed outdoor recreation projects. A careful analysis of the benefits which people derive from outdoor recreation provides a frame of reference for evaluating a recreational facility. A project should supply those benefits which are most highly demanded by the public. Fifteen benefits of recreation are defined and discussed. They are divided into two major categories; those which accrue to recreational participants and those which accrue to non-participants.This research was supported by a grant from the Division of Parks, State of Alaska

    Flight research capabilities of the NASA/Army rotor systems research aircraft

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    A description is given of the capabilities and limitations of the Rotor Systems Research Aircraft (RSRA) that was demonstrated during the development contract, and assesses the expected research capabilities of the RSRA on delivery to the government

    Electronics implementation of the solar neutron experiment

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    The electronic equipment design and function are discussed for the solar neutron counter experiment. Circuit diagrams are included

    Linear Optical CNOT Gate in the Coincidence Basis

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    We describe the operation and tolerances of a non-deterministic, coincidence basis, quantum CNOT gate for photonic qubits. It is constructed solely from linear optical elements and requires only a two-photon source for its demonstration.Comment: Submitted to Physical Review

    Evaluating implicit feedback models using searcher simulations

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    In this article we describe an evaluation of relevance feedback (RF) algorithms using searcher simulations. Since these algorithms select additional terms for query modification based on inferences made from searcher interaction, not on relevance information searchers explicitly provide (as in traditional RF), we refer to them as implicit feedback models. We introduce six different models that base their decisions on the interactions of searchers and use different approaches to rank query modification terms. The aim of this article is to determine which of these models should be used to assist searchers in the systems we develop. To evaluate these models we used searcher simulations that afforded us more control over the experimental conditions than experiments with human subjects and allowed complex interaction to be modeled without the need for costly human experimentation. The simulation-based evaluation methodology measures how well the models learn the distribution of terms across relevant documents (i.e., learn what information is relevant) and how well they improve search effectiveness (i.e., create effective search queries). Our findings show that an implicit feedback model based on Jeffrey's rule of conditioning outperformed other models under investigation

    The design, development, and flight test results of the Boeing 737 aircraft antennas for the ICAO demonstration of the TRSB microwave landing system

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    The Research Support Flight System, a modified Boeing 737, was used to evaluate the performance of several aircraft antennas and locations for the Time Reference Scanning Beam (TRSB) Microwave Landing System (MLS). These tests were conducted at the National Aviation Facilities Experimental Center (NAFEC), Atlantic City, New Jersey on December 18, 1975. The flight tests measured the signal strength and all pertinent MLS data during a straight-in approach, a racetrack approach, and ICAO approach profiles using the independent antenna-receiver combinations simultaneously on the aircraft. Signal drop-outs were experienced during the various approaches but only a small percentage could be attributed to antenna pattern effects
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