70,151 research outputs found

    Multispectral data restoration study

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    A digital resampling technique for LANDSAT data is reported that incorporates a deconvolution concept to minimize spatial and radiometric degradation of data during resampling for geometric correction. A quantitative comparison of cubic convolution and digital restoration methods establishes the latter as the superior technique

    Optical crossed-beam investigation of local sound generation in jets

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    Cross correlation of optical signals from two light beam sound detectors for jet noise source localizatio

    Projections and Dyadic Parseval Frame MRA Wavelets

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    A classical theorem attributed to Naimark states that, given a Parseval frame B\mathcal{B} in a Hilbert space H\mathcal{H}, one can embed H\mathcal{H} in a larger Hilbert space K\mathcal{K} so that the image of B\mathcal{B} is the projection of an orthonormal basis for K\mathcal{K}. In the present work, we revisit the notion of Parseval frame MRA wavelets from two papers of Paluszy\'nski, \v{S}iki\'c, Weiss, and Xiao (PSWX) and produce an analog of Naimark's theorem for these wavelets at the level of their scaling functions. We aim to make this discussion as self-contained as possible and provide a different point of view on Parseval frame MRA wavelets than that of PSWX.Comment: 19 page

    Measurement Issues in Assessing Farm Profitability through Cash Tax Returns

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    It is widely accepted that net farm income reported on an accrual-adjusted income statement is a more appropriate profitability measure than net farm income reported on Schedule F of the federal tax return, which is prepared using cash basis accounting. However, a common practice among agricultural lenders is to use Schedule F net farm income, which uses the cash basis of accounting, as a proxy for accrual-adjusted net farm income. A study of 1,045 individual Illinois farms’ records from 2002 through 2006 found the median absolute annual percentage difference between a three-year average cash and a three-year average accrual-adjusted net farm incomes is 57 percent for farms of stable size; 43 percent for farms with annual gross revenue increasing at rates of less than 5 percent, 50 percent at rates of 5-10 percent, and 58 percent at rates over 10 percent; and 61 percent for farms with a debt-to-asset ratio greater than 40 percent.Agricultural Finance,

    Isospectral deformations of closed Riemannian manifolds with different scalar curvature

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    We construct the first examples of continuous families of isospectral Riemannian metrics that are not locally isometric on closed manifolds, more precisely, on Sn×TmS^n\times T^m, where TmT^m is a torus of dimension m≥2m\ge 2 and SnS^n is a sphere of dimension n≥4n\ge 4. These metrics are not locally homogeneous; in particular, the scalar curvature of each metric is nonconstant. For some of the deformations, the maximum scalar curvature changes during the deformation.Comment: amstex, 10 pages, no figure

    Application of crossed beam technology to direct measurements of sound sources in turbulent jets, part 1

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    The mathematical bases for the direct measurement of sound source intensities in turbulent jets using the crossed-beam technique are discussed in detail. It is found that the problems associated with such measurements lie in three main areas: (1) measurement of the correct flow covariance, (2) accounting for retarded time effects in the measurements, and (3) transformation of measurements to a moving frame of reference. The determination of the particular conditions under which these problems can be circumvented is the main goal of the study
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