Search for dissertations about: "exponential transform"

Showing result 1 - 5 of 17 swedish dissertations containing the words exponential transform.

  2. 1. 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

  4. 2. Extension of separately analytic functions and applications to mathematical tomography : characterizing the range of the exponential Radon transform

    Author : Ozan Öktem; Slawomir Kolodziej; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; matematik; Mathematics;

    Abstract : The principal problem that is dealt with in the thesis is to characterize the range of the exponential Radon transform for both constant attenuation and angle dependent attenuation (in the latter case we assume that the attenuation is a trigonometric polynomial). Such results are also of interest in applications such as ECT (Emission Computed Tomography). READ MORE

  5. 3. Properties and tests for some classes of life distributions

    Author : Bengt Klefsjö; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Life distribution; survival function; exponential distribution; IFR; IFRA; NBUE; DMRL; HNBUE; shock model; total time on test transform; testing of exponentiality;

    Abstract : A life distribution and its survival function F = 1 - F with finitemean y = /q F(x)dx are said to be HNBUE (HNWUE) if F(x)dx < (>)U exp(-t/y) for t > 0. The major part of this thesis deals with the classof HNBUE (HNWUE) life distributions. READ MORE

  6. 4. Bayesian Inference for Microwave Diagnostics at Joint European Torus

    Author : Stefan Schmuck; Per Brunsell; Thomas Jonsson; Jakob Svensson; Laurie Porte; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; ECE; Bayesian; Fourier transform; spectroscopy; joint inference; length-scale; Gaussian process; microwave diagnostic; JET; Electrical Engineering; Elektro- och systemteknik;

    Abstract : The major goal of this thesis is to perform Bayesian inference jointly for electron kinetic profiles, a toroidal magnetic field correction, diagnostic sensitivities, and wall reflection properties given noisy measurements of four microwave diagnostics at the tokamak JET. Besides the measurements, this kind of inference considers prior knowledge, like profile length-scales, to update objectively the information about the physics parameters. READ MORE

  7. 5. Fast Radon Transforms and Reconstruction Techniques in Seismology

    Author : Viktor Nikitin; Matematik LTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Fourier transform FFT ; Radon transforms; GPU;

    Abstract : The measurements conducted in tomography and seismology typically yield large multidimensional data sets. This in combination with the fact that the data may have an irregular structure makes it computationally prohibitive to use simple reconstruction methods directly. READ MORE