Sökning: "wavefront reconstruction"

Hittade 5 avhandlingar innehållade orden wavefront reconstruction.

  1. 1. Wireless Channel Modeling and Reconstruction in Massive MIMO Systems

    Detta är en avhandling från Univeristy of Otago

    Författare :Aleksei Fedorov; [2019]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; channel modeling; 5G; 4G; LTE; MIMO; massive MIMO; localization; channel reconstruction; channel prediction; channel estimation; pilot contamination; phase noise; antenna array; orientation reconstruction; orientation estimation; channel inference; 3D channel modeling; realistic channel modeling; phase shifting; RACH synchronization; massive MIMO emulation; location estimation; system identification;

    Sammanfattning : The past few years have witnessed dramatic growth in the number of wirelessly connected devices, which will continue to increase in the future. Following this trend, the capacity of the wireless networks has been enhanced to provide high-quality service to tens of billions of devices. LÄS MER

  2. 2. Methods of Multi-Conjugate Adaptive Optics for Astronomy

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Ralf Flicker; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Adaptive optics; anisoplanatism; laser guide stars; performance estimation; wavefront reconstruction; extremely large telescopes; optics; Electromagnetism; Elektromagnetism; acoustics; Astronomy; akustik; space research; optik; multi-conjugate; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi; Fysicumarkivet A:2003:Flicker;

    Sammanfattning : This work analyses several aspects of multi-conjugate adaptive optics (MCAO) for astronomy. The research ranges from fundamental and technical studies for present-day MCAO projects, to feasibility studies of high-order MCAO instruments for the extremely large telescopes (ELTs) of the future. LÄS MER

  3. 3. Extremely Large Telescopes Optical Design and Wavefront Correction

    Detta är en avhandling från Lund Observatory, Lund University

    Författare :Alexander Gontcharov; [2003]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Astronomy; akustik; optik; Adaptive Optics; Extremely Large Telescopes; optical design methods; wavefront correction methods.; Electromagnetism; optics; Elektromagnetism; acoustics; space research; cosmic chemistry; Astronomi; rymdvetenskap; kosmisk kemi;

    Sammanfattning : An overview of the state of art within optical design of large astronomical telescopes is given. Recent advances within the field are presented. The importance of new computer-controlled mirror-polishing methods is emphasized. LÄS MER

  4. 4. Algorithms for Coherent Diffractive Imaging with X-ray Lasers

    Detta är en avhandling från Uppsala : Acta Universitatis Upsaliensis

    Författare :Benedikt J. Daurer; Filipe Maia; Tomas Ekeberg; Janos Hajdu; Richard Neutze; [2017]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; X-ray lasers; coherent diffractive imaging; algorithms; lensless imaging; flash diffractive imaging; flash X-ray imaging; aerosol injection; FEL; XFEL; CXI; CDI; FXI; Physics with specialization in Biophysics; Fysik med inriktning mot biofysik;

    Sammanfattning : Coherent diffractive imaging (CDI) has become a very popular technique over the past two decades. CDI is a "lensless" imaging method which replaces the objective lens of a conventional microscope by a computational image reconstruction procedure. LÄS MER

  5. 5. Polarization-Resolved Particle Holography

    Detta är en avhandling från Luleå University of Technology

    Författare :Johan Öhman; Mikael Sjödahl; Erik Olsson; Per Bergström; Pietro Ferraro; [2020]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimentell mekanik; Experimental Mechanics;

    Sammanfattning : In this thesis, measurement of particle fields using digital holography is the main subject. The questions investigated consider positioning, identification and sizing of nanometer and micrometer particles. The thesis explore these topics using both simulations and experimental measurements. LÄS MER