Search for dissertations about: "Integral transforms"

Showing result 1 - 5 of 12 swedish dissertations containing the words Integral transforms.

  2. 1. Inverse Problems in Tomography and Fast Methods for Singular Convolutions

    Author : Fredrik Andersson; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik; Unequally spaced FFT; Integral transforms; Singular integrals; Lippmann?Schwinger equation; Helmholtz equation; Inverse problems; Fast Gauss transform; Fast summation; Convolution; Radon transform; Tomography;

    Abstract : There are two, partially interlaced, themes treated in this thesis; inverse problems of tomographic type and fast and accurate methods for the application of convolution operators. Regarding the first theme, the inverse problem of Doppler tomography is considered and the Doppler moment transform is introduced for that purpose. READ MORE

  4. 2. On the modelling of ultrasonic testing using boundary integral equation methods

    Author : Jonathan Westlund; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Boundary element method; Regularization; Ultrasonics; Boundary integral equation method; T matrix.; Elastic waves; Nondestructive testing; Scattering;

    Abstract : Ultrasonic nondestructive testing has important applications in, for example, the nuclearpower and aerospace industries, where it is used to inspect safety-critical parts for flaws.For safe and reliable testing, mathematical models of the ultrasonic measurement systemsare invaluable tools. READ MORE

  5. 3. Application of fast backprojection techniques for some inverse problems of integral geometry

    Author : Stefan Nilsson; Frank Natterer; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : In this thesis we study some mathematical inverse problems concerning the determination of a function from circular averages, which appear in certain radar applications, and the determination of a function from its line integrals, which appear in the well known problem of computerized tomographic imaging (CT). The thesis is divided into three parts. READ MORE

  6. 4. Studies of vector tomography

    Author : Kent Stråhlén; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Doppler tomography; Doppler Radon transform; local tomography; vectorial k-plane transform; vectorial Radon transform; k-plane transform; Radon transform; tomography; vector tomography; Mathematics; Matematik;

    Abstract : The motivation to study the kind of problems appearing in this thesis has been ultrasound measurements of flows, from which velocity spectra along lines can be determined. These velocity spectra can mathematically be described by a new non-linear transform, here called the Doppler Spectral Transform (DST). READ MORE

  7. 5. Amoebas, Discriminants, and Hypergeometric Functions

    Author : Lisa Nilsson; Mikael Passare; Maurice Rojas; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; amoeba; coamoeba; discriminant; hypergeometric functions; Mellin transform; Algebra; geometry and mathematical analysis; Algebra; geometri och analys; Mathematics; matematik;

    Abstract : This thesis consists of six chapters. In Chapter 1 we give some historical background to the topic of the thesis together with the fundamental definitions and results that the thesis is based on. In Chapter 2 we study Mellin transforms of rational functions and investigate their analytic continuations. READ MORE