Sökning: "Spectral estimates"

Visar resultat 21 - 25 av 81 avhandlingar innehållade orden Spectral estimates.

  1. 21. Spectral Accuracy in Fast Ewald Methods and Topics in Fluid Interface Simulation

    Författare :Dag Lindbo; Anna-Karin Tornberg; Michael S. Siegel; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning :   This work contains two separate but related parts: one on spectrally  accurate and fast Ewald methods for electrostatics and viscous flow,  and one on micro- and complex fluid interface problems.  In Part I we are concerned with fast and spectrally accurate methods  to compute sums of slowly decaying potentials over periodic  lattices. LÄS MER

  3. 22. Qualitative and Spectral theory of some regular non-definite Sturm-Liouville problems

    Författare :Mervis Kikonko; Sten Kaijser; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Mathematics; Matematik;

    Sammanfattning : In this Licentiate thesis, we study some regular non-definite Sturm-Liouville problems. In this case, the weight function takes on both positive and negative signs on a given interval [a, b]. One feature of the non-definite Sturm-Liouville problem is the possible existence of non-real eigenvalues, unlike in the definite case (i.e. LÄS MER

  4. 23. Coercive estimates for the solutions of some singular differential equations and their applications

    Författare :Raya Akhmetkaliyeva; Gabriela Holubová; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matematik; Mathematics;

    Sammanfattning : This Licentiate thesis deals with the study of existence and uniqueness together with coercive estimates for solutions of certain differential equations. The thesis consists of four papers (papers A, B, C and D) and an introduction, which put these papers into a more general frame and which also serves as an overview of this interesting field of mathematics. LÄS MER

  5. 24. The diagnostic potential of the He I D3 spectral line in the solar atmosphere

    Författare :Tine Libbrecht; Jaime de la Cruz Rodríguez; Jorrit Leenaarts; Göran Scharmer; Valentín Martínez Pillet; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Sun; Line formation; Chromosphere; Spectro-Polarimetry; Flares; Reconnection; Astronomy; astronomi;

    Sammanfattning : The research question of my PhD is in a way a simple one: what can observations of the He I D3 line teach us about the solar chromosphere? This optical spectral line at 5876 Å is generally formed in the upper chromosphere, and is sensitive to the local magnetic field. The He I D3 line is also indirectly sensitive to heating of the transition region and corona, since it is resulting from a transition that occurs between levels in the triplet system of neutral helium. LÄS MER

  7. 25. Leaf Area Index of Scandinavian Forests Methods Using in situ and Remotely Sensed Data

    Författare :Helena Eriksson; Institutionen för naturgeografi och ekosystemvetenskap; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geologi; fysisk geografi; Physical geography; geomorphology; Geology; physical geography; leaf aggregation; specific leaf area SLA .; Växtekologi; Plant ecology; Leaf area index LAI ; canopy reflectance models; spectral vegetation indices; remote sensing; pedology; cartography; climatology; Fysisk geografi; geomorfologi; marklära; kartografi; klimatologi;

    Sammanfattning : This thesis deals with methods of obtaining the leaf area index (LAI) from remotely sensed satellite data. Initially, in situ estimation methods were investigated, since the accuracy of the remotely sensed estimates is dependent on the quality of these estimates. LÄS MER