8,454 research outputs found

    Fabrication of one silicon-germanium thermoelectric test unit Final report

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    Use of thermoelectric test unit to determine applicability of silicon-germanium power modules to space power systems requirement

    Flexible and practical modeling of animal telemetry data: hidden Markov models and extensions

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    We discuss hidden Markov-type models for fitting a variety of multistate random walks to wildlife movement data. Discrete-time hidden Markov models (HMMs) achieve considerable computational gains by focusing on observations that are regularly spaced in time, and for which the measurement error is negligible. These conditions are often met, in particular for data related to terrestrial animals, so that a likelihood-based HMM approach is feasible. We describe a number of extensions of HMMs for animal movement modeling, including more flexible state transition models and individual random effects (fitted in a non-Bayesian framework). In particular we consider so-called hidden semi-Markov models, which may substantially improve the goodness of fit and provide important insights into the behavioral state switching dynamics. To showcase the expediency of these methods, we consider an application of a hierarchical hidden semi-Markov model to multiple bison movement paths

    Using Self-Adaptive Evolutionary Algorithms to Evolve Dynamism-Oriented Maps for a Real Time Strategy Game

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    9th International Conference on Large Scale Scientific Computations. The final publication is available at link.springer.comThis work presents a procedural content generation system that uses an evolutionary algorithm in order to generate interesting maps for a real-time strategy game, called Planet Wars. Interestingness is here captured by the dynamism of games (i.e., the extent to which they are action-packed). We consider two different approaches to measure the dynamism of the games resulting from these generated maps, one based on fluctuations in the resources controlled by either player and another one based on their confrontations. Both approaches rely on conducting several games on the map under scrutiny using top artificial intelligence (AI) bots for the game. Statistic gathered during these games are then transferred to a fuzzy system that determines the map's level of dynamism. We use an evolutionary algorithm featuring self-adaptation of mutation parameters and variable-length chromosomes (which means maps of different sizes) to produce increasingly dynamic maps.TIN2011-28627-C04-01, P10-TIC-608

    06/10/1947 Letter from the War Assets Administration

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    Letter from John R.Fortin, District Director of the Maine War Assets Administration, to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-1947-04-06/1006/thumbnail.jp

    Consumer Attitudes toward Freshness Indicators on Perishable Food Products

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    Consumer/Household Economics, Food Consumption/Nutrition/Food Safety,

    Neutron star radii and crusts: uncertainties and unified equations of state

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    The uncertainties in neutron star (NS) radii and crust properties due to our limited knowledge of the equation of state (EOS) are quantitatively analysed. We first demonstrate the importance of a unified microscopic description for the different baryonic densities of the star. If the pressure functional is obtained matching a crust and a core EOS based on models with different properties at nuclear matter saturation, the uncertainties can be as large as 30%\sim 30\% for the crust thickness and 4%4\% for the radius. Necessary conditions for causal and thermodynamically consistent matchings between the core and the crust are formulated and their consequences examined. A large set of unified EOS for purely nucleonic matter is obtained based on 24 Skyrme interactions and 9 relativistic mean-field nuclear parametrizations. In addition, for relativistic models 17 EOS including a transition to hyperonic matter at high density are presented. All these EOS have in common the property of describing a 2  M2\;M_\odot star and of being causal within stable NS. A span of 3\sim 3 km and 4\sim 4 km is obtained for the radius of, respectively, 1.0  M1.0\;M_\odot and 2.0  M2.0\;M_\odot star. Applying a set of nine further constraints from experiment and ab-initio calculations the uncertainty is reduced to 1\sim 1 km and 22 km, respectively. These residual uncertainties reflect lack of constraints at large densities and insufficient information on the density dependence of the EOS near the nuclear matter saturation point. The most important parameter to be constrained is shown to be the symmetry energy slope LL which exhibits a linear correlation with the stellar radius, particularly for masses 1.0  M\sim 1.0\;M_\odot. Potential constraints on LL, the NS radius and the EOS from observations of thermal states of NS are also discussed. [Abriged]Comment: Submitted to Phys. Rev. C. Supplemental material not include

    New bases for a general definition for the moving preferred basis

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    One of the challenges of the Environment-Induced Decoherence (EID) approach is to provide a simple general definition of the moving pointer basis or moving preferred basis. In this letter we prove that the study of the poles that produce the decaying modes in non-unitary evolution, could yield a general definition of the relaxation, the decoherence times, and the moving preferred basis. These probably are the most important concepts in the theory of decoherence, one of the most relevant chapters of theoretical (and also practical) quantum mechanics. As an example we solved the Omnes (or Lee-Friedrich) model using our theory.Comment: 6 page

    Vacuum Decay Actions from Tunneling Potentials for General Spacetime Dimension

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    The tunneling potential method to calculate the action for vacuum decay is an alternative to the Euclidean bounce method that has a number of attractive features. In this paper we extend the formalism to general spacetime dimension d>2d>2 and use it to give simple proofs of several results. For Minkowski or Anti de Sitter false vacua, we show that gravity or higher barriers increase vacuum lifetime and describe a very clean picture of gravitational quenching of vacuum decay. We also derive the thin-wall limit of the action, show how detailed balance for dS to dS transitions works in the new formalism and how to obtain potentials for which the vacuum decay solution can be obtained analytically.Comment: 17 pages plus appendice

    Thermo-mechanical sensitivity calibration of nanotorsional magnetometers

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    We report on the fabrication of sensitive nanotorsional resonators, which can be utilized as magnetometers for investigating the magnetization dynamics in small magnetic elements. The thermo-mechanical noise is calibrated with the resonator displacement in order to determine the ultimate mechanical torque sensitivity of the magnetometer.Comment: 56th Annual Conference on Magnetism and Magnetic Material
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