• Title/Summary/Keyword: locally linear reconstruction scheme

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A Locally Linear Reconstruction scheme on arbitrary unstructured meshes (임의의 비정렬 격자계에서의 국지적 선형 재구성 기법)

  • Lee K. S.;Baek J. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.31-36
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    • 2003
  • A field reconstruction scheme for a cell centered finite volume method on unstructured meshes is developed. Regardless of mesh quality, this method is exact within a machine accuracy if the solution is linear, which means it has full second order accuracy. It does not have any limitation on cell shape except convexity of the cells and recovers standard discretization stencils at structured orthogonal grids. Accuracy comparisons with other popular reconstruction schemes are performed on a simple example.

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An unstructured finite volume method for unsteady incompressible flows with full second order accuracy (2차 정확도를 가지는 비정상 비압축성 유동장 해석을 위한 비정렬 유한 체적법의 개발)

  • Lee K. S.;Baek J. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2004.03a
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    • pp.71-76
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    • 2004
  • An extension of our recently developed locally linear reconstruction scheme to 2 dimensional incompressible flow solver is presented. The solver is based on a semi-implicit fractional step method in which the convective term is discretized by Adams-Bashforth method and the diffusion term by Crank-Nicolson method. Several numerical examples are tested to demonstrate the mesh type independent accuracy of the solver, which include decaying vortex flow, square cavity flow, and flow around a circular cylinder. The above examples are solved on quadrilateral or hybrid meshes. For all numerical examples, we obtained reasonable results.

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High Resolution Reconstruction of Multispectral Imagery with Low Resolution (저해상도 Multispectral 영상의 고해상도 재구축)

  • Lee, Sang-Hoon
    • Korean Journal of Remote Sensing
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    • v.23 no.6
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    • pp.547-552
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    • 2007
  • This study presents an approach to reconstruct high-resolution imagery for multispectral imagery of low-resolution using panchromatic imagery of high-resolution. The proposed scheme reconstructs a high-resolution image which agrees with original spectral values. It uses a linear model of high-and low- resolution images and consists of two stages. The first one is to perform a global estimation of the least square error on the basis of a linear model of low-resolution image associated with high-resolution feature, and next local correction then makes the reconstructed image locally fit to the original spectral values. In this study, the new method was applied to KOMPSAT-1 EOC image of 6m and LANDSAT ETM+ of 30m, and an 1m RGB image was also generated from 4m IKONOS multispectral data. The results show its capability to reconstruct high-resolution imagery from multispectral data of low-resolution.