Sökning: "high order accuracy"

Visar resultat 26 - 30 av 517 avhandlingar innehållade orden high order accuracy.

  1. 26. Ensuring the intended volume is given the intended absorbed dose in radiotherapy: Managing geometric variations and treatment hazards

    Författare :Ola Holmberg; Malmö Medicinsk strålningsfysik; []
    Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; medical instrumentation; tomography; radiology; Clinical physics; safety; risk; hazard; organ motion; set-up; margins; volume definition; radiotherapy; accuracy; Klinisk fysiologi; radiologi; tomografi; medicinsk instrumentering; Radiopharmaceutical technology; Radiofarmaceutisk teknik;

    Sammanfattning : Methods for ensuring that the intended volume receives the intended absorbed dose in radiotherapy have been investigated. In order to optimise radiation treatment of cancer, geometric variations in the treatment chain need to be controlled. Furthermore, hazards potentially leading to unintended irradiation need to be controlled. LÄS MER

  3. 27. Finite Difference and Discontinuous Galerkin Methods for Wave Equations

    Författare :Siyang Wang; Gunilla Kreiss; Thomas Hagstrom; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Wave propagation; Finite difference method; Discontinuous Galerkin method; Stability; Accuracy; Summation by parts; Normal mode analysis; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Wave propagation problems can be modeled by partial differential equations. In this thesis, we study wave propagation in fluids and in solids, modeled by the acoustic wave equation and the elastic wave equation, respectively. LÄS MER

  4. 28. Dicke narrowing and speed-dependent effects in dispersion signals : Influence on assessment of concentration and spectral parameters by noise-immune cavity-enhanced optical heterodyne molecular spectrometry

    Författare :Junyang Wang; Ove Axner; Livio Gianfrani; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Dicke narrowing; Speed-dependent effects; Dispersion signals; Noise-immune cavity-enhanced optical heterodyne molecular spectrometry NICE-OHMS ; accuracy;

    Sammanfattning : Laser spectroscopic techniques have, during the last decades, demonstrated an extraordinary capability for sensitive detection of molecular constituents in gas phase. Since spectra from such techniques constitute unique and characteristic signatures for each type of species, these techniques enable investigations of molecular structures as well as detection of the presence of species in a gas mixture. LÄS MER

  5. 29. First-Order Algorithms for Communication Efficient Distributed Learning

    Författare :Sarit Khirirat; Mikael Johansson; Martin Jaggi; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Communication efficient learning; Optimization algorithms; Quantization; Error compensation; First-order algorithms; Stochastic gradient descent; Tillämpad matematik och beräkningsmatematik; Applied and Computational Mathematics; Optimeringslära och systemteori; Optimization and Systems Theory; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Technological developments in devices and storages have made large volumes of data collections more accessible than ever. This transformation leads to optimization problems with massive data in both volume and dimension. LÄS MER

  7. 30. First-Order Algorithms for Communication Efficient Distributed Learning

    Författare :Sarit Khirirat; Mikael Johansson; Tong Zhang; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Communication efficient learning; Optimization algorithms; Quantization; Error compensation; First-order algorithms; Stochastic gradient descent; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Innovations in numerical optimization, statistics and high performance computing have enabled tremendous advances in machine learning algorithms, fuelling applications from natural language processing to autonomous driving.To deal with increasing data volumes, and to keep the training times of increasingly complex machine learning models reasonable, modern optimization algorithms distribute both data and computations over a large number of machines. LÄS MER