Sökning: "Nonlinear methods"

Visar resultat 1 - 5 av 525 avhandlingar innehållade orden Nonlinear methods.

  1. 1. Numerical methods for Sylvester-type matrix equations and nonlinear eigenvalue problems

    Författare :Emil Ringh; Elias Jarlebring; Johan Karlsson; Per Enqvist; Daniel Kressner; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Matrix equations; Lyapunov equation; Sylvester equation; nonlinear eigenvalue problems; two-parameter eigenvalue problems; Krylov methods; iterative methods; preconditioning; projection methods; Matrisekvationer; Lyapunovekvationen; Sylvesterekvationen; ickelinjära egenvärdesproblem; två-parameters egenvärdesproblem; Krylovmetoder; iterativa metoder; förkonditionering; projektionsmetoder; Tillämpad matematik och beräkningsmatematik; Applied and Computational Mathematics; Optimization and Systems Theory; Optimeringslära och systemteori; Numerical Analysis; Numerisk analys;

    Sammanfattning : Linear matrix equations and nonlinear eigenvalue problems (NEP) appear in a wide variety of applications in science and engineering. Important special cases of the former are the Lyapunov equation, the Sylvester equation, and their respective generalizations. These appear, e.g. LÄS MER

  3. 2. Turbomachinery Aeroacoustic Calculations using Nonlinear Methods

    Författare :Martin Olausson; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nonlinear; CFD; Time Spectral; CAA; Ffowcs-Williams Hawkings; Broadband; Time lag; Computational Aeroacoustics; Fan-Noise; Rotor-Stator interaction; Buffer layer; Oscillating sphere; Newton-GMRES; Computational Fluid Dynamics; Acoustic analogies; Sponge; Counter-Rotating Propfan; Harmonic Balance Technique; Tone; FWH; Chorochronic periodicity; Hybrid RANS LES;

    Sammanfattning : Noise regulations for aircraft that fly over populated areas are becoming continuously stricter. This in combination with increasing computational capabilities has boosted interest in aeroacoustic computations in the aerospace industry. LÄS MER

  4. 3. Development and improvement of methods for characterization of HPLC stationary phases

    Författare :Torgny Undin; Torgny Fornstedt; Jörgen Samuelsson; Anders Törncrona; Johan Ekeroth; Douglas Westerlund; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Adsorption isotherms; Elution by characteristic points; Inflection points; Single component adsorption; Elution by characteristic points method; Slope data; ECP-slope method; Adsorption; Adsorption energy distribution; Adsorption isotherms; AED; Characterization of adsorption processes; Chromatographic analysis; Chromatography; Hydrophobic-subtraction method HSM ; Hydrophobicity; Linear methods; Linear Models; Liquid chromatography; metoprolol; Non-linear methods; Nonlinear methods; phenol; priority journal; propranolol; Retention mechanism; reversed phase liquid chromatography; Solvation; Subtraction method; Thermodynamics; Chemistry with specialization in Surface Biotechnology; Kemi med inriktning mot ytbioteknik;

    Sammanfattning : High Performance Liquid Chromatography (HPLC) is a widely used tech-nique both for detecting and purifying substances in academy and in the industry. In order to facilitate the use of, and knowledge in HPLC, character-ization of stationary phases is of utmost importance. LÄS MER

  5. 4. Approaches to accelerate methods for solving systems of equations arising in nonlinear optimization

    Författare :David Ek; Anders Forsgren; Jacek Gondzio; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optimization; mathematical programming; interior-point methods; approximate solutions to systems of linear equations; method of conjugate gradients; quasi-Newton methods; modified Newton methods; Ickelinjär optimering; matematisk programmering; inre-punktsmetoder; approximativa lösningar till linjära ekvationssystem; konjugerade gradientmetoden; kvasi-Newtonmetoder; modifierade Newtonmetoder.; Optimization and Systems Theory; Optimeringslära och systemteori;

    Sammanfattning : Methods for solving nonlinear optimization problems typically involve solving systems of equations. This thesis concerns approaches for accelerating some of those methods. In our setting, accelerating involves finding a trade-off between the computational cost of an iteration and the quality of the computed search direction. LÄS MER

  7. 5. Geometric Methods for some Nonlinear Wave Equations

    Författare :Jonatan Lenells; Matematik (naturvetenskapliga fakulteten); []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Natural science; Geodesic flow; Nonlinear wave equations; Geometric methods; Naturvetenskap;

    Sammanfattning : A number of results related to the geometric interpretation of some dispersive nonlinear wave equations are presented. It is first described how some well-known shallow water equations arise geometrically as Euler equations for the geodesic flow on the Virasoro group endowed with certain right-invariant metrics. LÄS MER