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Adaptive Mollifiers -- High Resolution Recovery of Piecewise Smooth Data from its Spectral Information

Applied Math

Speaker: Jared Tanner, UC Davis
Location: 693 Kerr
Start time: Fri, Oct 4 2002, 4:10PM

Spectral projections enjoy high order convergence for globally smooth functions. However, a single discontinuity introduces O(1) spurious oscillations, Gibbs' Phenomena, and reduces the high order convergence rate to first order. We will show how adaptive mollifiers can be used to recover the high order convergence rate as well as remove the spurious oscillations found near a discontinuity. In addition, when these adaptive mollifiers are applied to an equidistant sampling of piecewise smooth functions we obtain an exponentially accurate "interpolation" scheme. This is a powerful new tool for equidistant data with applications in image processing and non-linear conservation laws. Time permitting, applications to scalar hyperbolic conservation laws will be shown. This research was conducted jointly with Eitan Tadmor.