1,721,070 research outputs found
Il modello di Black-Scholes per la determinazione del pezzo delle opzioni europee
No full textStabilimento Tipografico De Rosa, Cosenz
Inverse problems involving smart obstacles2006 IEEE Antennas and Propagation Society International Symposium
No full textThe use of the Herglotz Function Method to reconstruct obstacles from real and from synthetic scattering data
No full textWe consider the problem of the reconstruction of the shape of an obstacle from some knowledge of the scattered waves generated from the interaction of the obstacle with known incident waves. More precisely we study this inverse scattering problem considering acoustic waves or electromagnetic waves. In both cases the waves are assumed harmonic in time. The obstacle is assumed cylindrically symmetric and some special incident waves are considered. This allows us to formulate the two scattering problems, i.e. the acoustic scattering problem and the electromagnetic scattering problem, as a boundary value problem for the scalar Helmholtz equation in two independent variables. The numerical algorithms proposed are based on the Herglotz Function Method, which has been introduced by Colton and Monk.(1) We report the results obtained with these algorithms in the reconstruction of simple obstacles with Lipschitz boundary using experimental electromagnetic scattering data, that is the Ipswich Data(2,3) and in the reconstruction of "multiscale obstacles" using synthetic acoustic scattering data
A numerical method to solve the inverse medium problem: an application to the IPSWICH data II
No full textThe exact response of a two dimensional flat layered medium to a probing pulse: an application to a layer stripping reconstruction procedure
No full textSolving the phase unwrapping problem by a parametrized network optimization approach
No full textNonconvex Optimization and its Application
High performance algorithms for time dependent wave scattering from a bounded obstacle
No full textProceeding
A fast phase unwrapping algorithm for SAR interferometry
No full textPhase unwrapping is the key problem in building the elevation map of a scene from interferometric synthetic aperture radar (SAR) system data. Phase unwrapping consists in the reconstruction of the phase difference of the radiation received by two SAR systems as a function of the azimuth and slant range coordinates. The data available to reconstruct the phase difference are a measure of the difference module 2 pi, We propose a phase unwrapping method that makes use of the equivalent, in a discrete space, of the irrotational property of a gradient vector field. This property if used first to locate the areas where the discrete vector held estimated from the available data must be corrected, and then, with the knowledge of some a priori information, to perform the correction needed to obtain a useful estimate of the discrete gradient of the phase difference function, from which the phase difference function is reconstructed. The use of the fast Fourier transform makes it possible to have a fast algorithm, that is to process an image of N pixel in 0(N log N) elementary operations. Tests of the method proposed here on real and simulated data are presented
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