Sökning: "summation"

Visar resultat 1 - 5 av 98 avhandlingar innehållade ordet summation.

  1. 1. Summation formulae and zeta functions

    Författare :Johan Andersson; Mikael Passare; Aleksandar Ivic; Stockholms universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; zeta function; summation formula; automorphic form; modular group; Kloosterman sum; Selberg theory; power sum method; MATHEMATICS; MATEMATIK;

    Sammanfattning : This thesis in analytic number theory consists of 3 parts and 13 individual papers.In the first part we prove some results in Turán power sum theory. We solve a problem of Paul Erdös and disprove conjectures of Paul Turán and K. Ramachandra that would have implied important results on the Riemann zeta function. LÄS MER

  3. 2. Comparative optics of prosobranch eyes

    Författare :Jan-Olof Seyer; Biologiska institutionen; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Ampularia; Littorina; Strombus; evolution; visual ecology; summation; convergence; optic nerve; resolution; sensitivity; optics; eye; gastropod; prosobranch; Animal anatomy; animal morphology; Djurs anatomi och morfologi;

    Sammanfattning : Functional aspects of the large diversity of eye design in prosobranch molluscs was investigated using morphological and optical methods. Three species from different habitats were investigated. Littorina littorea from Scandinavian intertidal rock habitats, Strombus raninus and S. gigas from tropical sand-flats and Ampularia sp. LÄS MER

  4. 3. High order summation-by-parts methods in time and space

    Författare :Tomas Lundquist; Jan Nordström; Peter Eliasson; David A. Kopriva; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; summation-by-parts; time integration; stiff problems; weak initial conditions; high order methods; simultaneous-approximation-term; finite difference; discontinuous Galerkin; spectral methods; conservation; energy stability; complex geometries; non-conforming grid interfaces; interpolation;

    Sammanfattning : This thesis develops the methodology for solving initial boundary value problems with the use of summation-by-parts discretizations. The combination of high orders of accuracy and a systematic approach to construct provably stable boundary and interface procedures makes this methodology especially suitable for scientific computations with high demands on efficiency and robustness. LÄS MER

  5. 4. Applications of summation-by-parts operators

    Författare :Oskar Ålund; Jan Nordström; Andrew Ross Winters; Murtazo Nazarov; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : Numerical solvers of initial boundary value problems will exhibit instabilities and loss of accuracy unless carefully designed. The key property that leads to convergence is stability, which this thesis primarily deals with. LÄS MER

  7. 5. Summation-by-Parts Finite Difference Methods for Wave Propagation and Earthquake Modeling

    Författare :Vidar Stiernström; Ken Mattsson; Mark H. Carpenter; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Finite difference method; high-order accuracy; stability; summation-by-parts; wave propagation; earthquake modeling; inverse problems; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

    Sammanfattning : Waves manifest in many areas of physics, ranging from large-scale seismic waves in geophysics down to particle descriptions in quantum physics. Wave propagation may often be described mathematically by partial differential equations (PDE). Unfortunately, analytical solutions to PDEs are in many cases notoriously difficult to obtain. LÄS MER