2,437 research outputs found

    Algorithms for randomness in the behavioral sciences: A tutorial

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    Simulations and experiments frequently demand the generation of random numbera that have specific distributions. This article describes which distributions should be used for the most cammon problems and gives algorithms to generate the numbers.It is also shown that a commonly used permutation algorithm (Nilsson, 1978) is deficient

    Requirement specifications for standardized Local Area Networks and applications for Naval Aviation squadrons.

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    This thesis will address unique characteristics and requirements for implementing a Local Area Network (LAN) and standard applications at the Naval Aviation squadron level. The introduction will present the history and basic concept of LAN's at squadrons as well as defining the problem that exists. Examples of Local Area Networks are presented to provide a basic understanding of the technology involved. The organization of Naval Aviation squadrons is discussed to illustrate the high level functional requirements. Areas to be covered in the requirements specifications are then discussed to ensure completeness and the overall success of this concept. Performance, documentation, training, support and security are a few of the issues that are addressed. Complete specifications, a coordinated and well thought out plan and designation of a project manager are critical elements that cannot be ignored if the project is to succeed.http://archive.org/details/requirementspeci00masoLieutenant, United States Navy ReserveApproved for public release; distribution is unlimited

    Application of advanced technology to space automation

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    Automated operations in space provide the key to optimized mission design and data acquisition at minimum cost for the future. The results of this study strongly accentuate this statement and should provide further incentive for immediate development of specific automtion technology as defined herein. Essential automation technology requirements were identified for future programs. The study was undertaken to address the future role of automation in the space program, the potential benefits to be derived, and the technology efforts that should be directed toward obtaining these benefits

    Feedback control optimisation of ESR experiments

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    Numerically optimised microwave pulses are used to increase excitation efficiency and modulation depth in electron spin resonance experiments performed on a spectrometer equipped with an arbitrary waveform generator. The optimisation procedure is sample-specific and reminiscent of the magnet shimming process used in the early days of nuclear magnetic resonance -- an objective function (for example, echo integral in a spin echo experiment) is defined and optimised numerically as a function of the pulse waveform vector using noise-resilient gradient-free methods. We found that the resulting shaped microwave pulses achieve higher excitation bandwidth and better echo modulation depth than the pulse shapes used as the initial guess. Although the method is theoretically less sophisticated than simulation based quantum optimal control techniques, it has the advantage of being free of the linear response approximation; rapid electron spin relaxation also means that the optimisation takes only a few seconds. This makes the procedure fast, convenient, and easy to use. An important application of this method is at the final stage of the implementation of theoretically designed pulse shapes: compensation of pulse distortions introduced by the instrument. The performance is illustrated using spin echo and out-of-phase electron spin echo envelope modulation experiments. Interface code between Bruker SpinJet arbitrary waveform generator and Matlab is included in versions 2.2 and later of the Spinach library

    A conceptual framework for using Doppler radar acquired atmospheric data for flight simulation

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    A concept is presented which can permit turbulence simulation in the vicinity of microbursts. The method involves a large data base, but should be fast enough for use with flight simulators. The model permits any pilot to simulate any flight maneuver in any aircraft. The model simulates a wind field with three-component mean winds and three-component turbulent gusts, and gust variation over the body of an aircraft so that all aerodynamic loads and moments can be calculated. The time and space variation of mean winds and turbulent intensities associated with a particular atmospheric phenomenon such as a microburst is used in the model. In fact, Doppler radar data such as provided by JAWS is uniquely suited for use with the proposed model. The concept is completely general and is not restricted to microburst studies. Reentry and flight in terrestrial or planetary atmospheres could be realistically simulated if supporting data of sufficient resolution were available

    Combine harvester monitoring based on a single-board microcomputer

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    Reduction in grain loss of combine harvesters will increase the efficiency of harvesters and the net income of the farmer. Grain lost in the field may emerge as a weed in the crop rotation and harbor unwanted insects;A simulation model was developed for calculating the various components of loss and yield in the combine. Forward speed was determined for each day of operation. Yield, total area harvested, and losses were also calculated;Transducers were designed for measuring yield, walker loss, shoe loss and forward speed of a combine and a model of the combine was constructed in the laboratory for evaluating these transducers. Hardware for signal amplification and conversion was designed and constructed and software was developed for a single-board microcomputer which collected and displayed the variables measured;Measurement of these variables should help in the control of the combine harvester

    The use of an optical data acquisition system for bladed disk vibration analysis

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    A new concept in instrumentation was developed by engineers at NASA Lewis Research Center to collect vibration data from multi-bladed rotors. This new concept, known as the optical data acquisition system, uses optical transducers to measure bladed tip delections by reflection light beams off the tips of the blades as they pass in front of the optical transducer. By using an array of transducers around the perimeter of the rotor, detailed vibration signals can be obtained. In this study, resonant frequencies and mode shapes were determined for a 56 bladed rotor using the optical system. Frequency data from the optical system was also compared to data obtained from strain gauge measurements and finite element analysis and was found to be in good agreement

    Development of a fault-tolerant microprocessor based computer system for space flight

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    A methodology for the design of a tightly coupled, highly reliable microprocessor based computer system is described. The concept of triple modular redundancy with sparing is used. The notion of synchronizing by using a single crystal oscillator is examined. The use of decoders to replace voters is also used. The decoders not only isolate the failed module but also allow error identification to be accomplished. Each module is to have its own RAM memory. The necessary circuitry to select a correct memory and the corresponding DMA controller was designed
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