Search for dissertations about: "Fourier transforms"

Showing result 1 - 5 of 20 swedish dissertations containing the words Fourier transforms.

  2. 1. 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

  4. 2. Summability of Fourier transforms of functions from Lorentz spaces

    Author : Aigerim Kopezhanova; Lars-Erik Persson; Peter Wall; Erlan Nursultanov; Mikhael Goldman; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Abstract : This PhD thesis is devoted to the study of relations between integrability properties of functions and summability properties of its Fourier coefficients and transforms. The relations are given in terms of generalized weighted Lorentz norms, where the weights have some additional growth properties. READ MORE

  5. 3. Leveraging Intermediate Representations for High-Performance Portable Discrete Fourier Transform Frameworks : with Application to Molecular Dynamics

    Author : Måns Andersson; Stefano Markidis; Artur Podobas; Niclas Jansson; Ivy Bo Peng; Hartwig Anzt; KTH; []
    Keywords : Intermediate Representation; Discrete Fourier Transform; Fast Fourier Transform; Molecular Dynamics; Mellankod; diskret Fouriertransform; snabb Fouriertransform; Molekyldynamik;

    Abstract : The Discrete Fourier Transform (DFT) and its improved formulations, the Fast Fourier Transforms (FFTs), are vital for scientists and engineers in a range of domains from signal processing to the solution of partial differential equations.  A growing trend in Scientific Computing is heterogeneous computing, where accelerators are used instead or together with CPUs. READ MORE

  6. 4. Some new Lizorkin multiplier theorems for Fourier series and transforms

    Author : Lyazzat Sarybekova; Luleå tekniska universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Abstract : This Licentiate Thesis is devoted to the study of Fourier series and Fourier transform multipliers and contains three papers (papers A - C) together with an introduction, which put these papers into a general frame. In paper A a generalization of the Lizorkin theorem on Fourier multipliers is proved. READ MORE

  7. 5. Arbitrary Waveform Impedance Spectroscopy for Characterization and Diagnostics of High Voltage Insulation

    Author : Björn Sonerud; Chalmers tekniska högskola; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; insulation testing; aging; monitoring; discrete Fourier transforms; Dielectric measurements; dielectric materials;

    Abstract : In high voltage engineering the dielectric response technique is a widely used tool both for characterization of insulation materials and for diagnostics of components such as transformers and cables. Currently available techniques are not capable of measuring on-line which would be advantageous; when characterizing a material and evaluating the effect of different voltage magnitudes, waveforms and temperatures it is desirable to be able to observe the continuous development of the dielectric properties. READ MORE