Sökning: "saddle point systems"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden saddle point systems.

1. 1. Ghosts and machines : regularized variational methods for interactive simulations of multibodies with dry frictional contacts

   Författare :Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Discrete mechanics; Variational method; Contact problems; Impacts; Least action principle; Saddle point problems; Lagrange Multipliers; Constrained systems; Multibody Systems; Numerical regularization; Constraint realization; Constraint stabilization; Dry friction; Differential Algebraic Equations; Nonsmooth problems; Linear Complementarity; Quaternion algebra; Numerical linear algebra; Physics modeling; Interactive simulation; Numerical stability; Rigid body dynamics; Dissipative systems; Computational physics; Beräkningsfysik;

   Sammanfattning : A time-discrete formulation of the variational principle of mechanics is used to provide a consistent theoretical framework for the construction and analysis of low order integration methods. These are applied to mechanical systems subject to mixed constraints and dry frictional contacts and impacts---machines. LÄS MER

3. 2. Optimizing Networked Systems and Inverse Optimal Control

   Författare :Han Zhang; Xiaoming Hu; Elias Jarlebring; Yiguang Hong; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Networked systems; energy optimal consensus control; semi-definite programming; distributed optimization; inverse optimal control; Mathematics; Matematik;

   Sammanfattning : This thesis is concerned with the problems of optimizing networked systems, including designing a distributed energy optimal consensus controller for homogeneous networked linear systems, maximizing the algebraic connectivity of a network by projected saddle point dynamics. In addition, the inverse optimal control problems for discrete-time finite time-horizon Linear Quadratic Regulators (LQRs) are considered. LÄS MER

4. 3. Computational Techniques for Coupled Flow-Transport Problems

   Författare :Martin Kronbichler; Gunilla Kreiss; Jean-Luc Guermond; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Finite element method; saddle point systems; two-phase flow; level set method; phase field method; stabilization; contact line dynamics; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : This thesis presents numerical techniques for solving problems of incompressible flow coupled to scalar transport equations using finite element discretizations in space. The two applications considered in this thesis are multi-phase flow, modeled by level set or phase field methods, and planetary mantle convection based on the Boussinesq approximation. LÄS MER

5. 4. Analysis and Implementation of Preconditioners for Prestressed Elasticity Problems : Advances and Enhancements

   Författare :Ali Dorostkar; Maya Neytcheva; Thomas Huckle; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; FEM; Saddle point matrix; Preconditioning; Schur complement; Generalized Locally Toeplitz; Prestressed elasticity; Scientific Computing; Beräkningsvetenskap;

   Sammanfattning : In this work, prestressed elasticity problem as a model of the so-called glacial isostatic adjustment (GIA) process is studied. The model problem is described by a set of partial differential equations (PDE) and discretized with a mixed finite element (FE) formulation. LÄS MER

7. 5. Electronic Structure and Transport in Nanofabricated Low-Dimensional Semiconductor Systems : A theoretical study

   Författare :Chuan-Kui Wang; Hongqi Xu; Linköpings universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

   Sammanfattning : Systematic studies of the transport properties in one type of low-dimensional semiconductor nanostructures, in which the motion of carriers is governed by quantum mechanics, are presented in this thesis. In addition, the electronic states in lowdimensional systems fabricated from GaAs / Al?Ga1-?As heterostructures have been investigated by using both transport methods and the static calculations. LÄS MER