Sökning: "eigenvalue problem"

Visar resultat 26 - 30 av 62 avhandlingar innehållade orden eigenvalue problem.

1. 26. Riemann-Hilbert methods in general relativity and random matrix theory

   Författare :Julian Mauersberger; Jonatan Lenells; Tom Claeys; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : This thesis focuses on problems in general relativity and random matrix theory that can be solved by means of Riemann-Hilbert techniques. The first part of the thesis is dedicated to solving boundary value problems related to colliding plane waves in vacuum in general relativity. LÄS MER

3. 27. Waves and instabilities through the lens of asymptotic analysis

   Författare :Anthony Bonfils; John Wettlaufer; Dhrubaditya Mitra; Woosok Moon; Jerome Neufeld; Stockholms universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; waves; wrinkles; instabilities; Theoretical Physics; teoretisk fysik;

   Sammanfattning : Understanding the interaction of water waves with winds and marine currents is a fundamental problem in geophysical fluid dynamics. From the point of view of hydrodynamic stability, surface waves are regarded as perturbations of an inviscid parallel shear flow modeling the wind in the air and the current in the water. LÄS MER

4. 28. Microinstabilities in Advanced Tokamak and Stellarator Geometries

   Författare :Ansar Mahmood; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; tokamaks; microinstabilities; fusion plasmas; ITG; drift waves; stellarators;

   Sammanfattning : The anomalous particle and heat transport observed in magnetically confined plasmas is generally attributed to plasma turbulence driven by short-scale instabilities, called microinstabilities. Understanding the stability limits of microinstabilities and their dependency on the equilibrium configuration is of paramount importance in the effort to predict the performance of future fusion devices such as the International Thermonuclear Experimental Reactor (ITER). LÄS MER

5. 29. Tensor Products of Highest Weight Representations and Skew-Symmetric Matrix Equations A+B+C=0

   Författare :Ida Säfström; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Highest weight respresentation; tensor product decomposition; orthogonal algebra; skew-symmetric matrix; Horn’s conjecture; moment map; coadjoint orbit; flag manifold; general linear algebra; infinite dimensional unitary representation; general linear algebra;

   Sammanfattning : The question of characterizing the eigenvalues for the sum of two Hermitian matrices, was solved in 1999, after almost a century of efforts. The saturation conjecture for GL_C(n) was proven by Knutson and Tao, filling in the last gap in Horn’s conjecture. LÄS MER

7. 30. Large-Scale Optimization With Machine Learning Applications

   Författare :Vien Van Mai; Mikael Johansson; Alexandre d'Aspremont; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Optimization algorithms; Anderson acceleration; finite-sum; first-order methods; Optimization and Systems Theory; Optimeringslära och systemteori; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis aims at developing efficient algorithms for solving some fundamental engineering problems in data science and machine learning. We investigate a variety of acceleration techniques for improving the convergence times of optimization algorithms. LÄS MER