Sökning: "Spectral estimates"

Visar resultat 16 - 20 av 81 avhandlingar innehållade orden Spectral estimates.

  1. 16. Measuring the solar atmosphere

    Författare :Jaime de la Cruz Rodríguez; Göran Scharmer; Dan Kiselman; Mats Carlsson; Gianna Cauzzi; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; Chromosphere; Spectropolarimetry; Solar observations; Spectral lines; Solar magnetic fields; Astronomy; Astronomi; Astronomy; astronomi;

    Sammanfattning : The new CRISP filter at the Swedish 1-m Solar Telescope provides opportunities for observing the solar atmosphere with unprecedented spatial resolution and cadence. In order to benefit from the high quality of observational data from this instrument, we have developed methods for calibrating and restoring polarized Stokes images, obtained at optical and near infrared wavelengths, taking into account field-of-view variations of the filter properties. LÄS MER

  3. 17. A convex optimization approach to complexity constrained analytic interpolation with applications to ARMA estimation and robust control

    Författare :Anders Blomqvist; Anders Lindquist; Giorgio Picci; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematical optimization; systems theory; analytic interpolation; moment matching; Nevanlinna-Pick interpolation; spectral estimation; convex optimization; Optimeringslära; systemteori; Optimization; systems theory; Optimeringslära; systemteori;

    Sammanfattning : Analytical interpolation theory has several applications in systems and control. In particular, solutions of low degree, or more generally of low complexity, are of special interest since they allow for synthesis of simpler systems. LÄS MER

  4. 18. Spectral Properties of Type Ia Supernovae and Implications for Cosmology

    Författare :Jakob Nordin; Ariel Goobar; Mark Phillips; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; cosmology; spectroscopy; supernovae; Physics; Fysik; Cosmology; Kosmologi; Extragalactical astronomy; Extragalaktisk astronomi; fysik; Physics;

    Sammanfattning : Type Ia supernovae can, for a short period of time, reach the same brightness as an entire galaxy. They are responsible for the creation of a large fraction of all heavy elements and can be used, as standard candles, to prove that the expansion of the universe is accelerating. Yet, we do not fully understand them. LÄS MER

  5. 19. Asymptotic Problems on Homogeneous Spaces

    Författare :Anders Södergren; Andreas Strömbergsson; Dennis Hejhal; Jens Marklof; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Analysis on homogeneous spaces; hyperbolic manifolds; spectral theory; equidistribution; the space of lattices; length statistics; Poisson process; moments; Epstein zeta function; value distribution; height function.; MATHEMATICS; MATEMATIK; Mathematics; Matematik;

    Sammanfattning : This PhD thesis consists of a summary and five papers which all deal with asymptotic problems on certain homogeneous spaces. In Paper I we prove asymptotic equidistribution results for pieces of large closed horospheres in cofinite hyperbolic manifolds of arbitrary dimension. LÄS MER

  7. 20. Classification of different types of snow using spectral and angular imaging

    Författare :Lavan Kumar Eppanapelli; Luleå tekniska universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Experimental Mechanics; Experimentell mekanik;

    Sammanfattning : The current thesis work details a non-contact detection approach concerningclassification of snow with different physical properties such as grain size, densityand specific surface area (SSA). In this approach, reflected light from snowsurfaces is measured as a function of wavelength and viewing geometry. LÄS MER