Search for dissertations about: "variational regularization"

Found 5 swedish dissertations containing the words variational regularization.

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

    Author : Claude Lacoursière; Bo Kåggström; Ander Klarbring; Umeå universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; 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;

    Abstract : 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. READ MORE

  2. 2. Multidimensional inverse problems in imaging and identification using low-complexity models, optimal mass transport, and machine learning

    Author : Axel Ringh; Johan Karlsson; Rodolphe Sepulchre; KTH; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Inverse problems; convex optimization; variational regularization; trigonometric moment problems; optimal mass transport; computed tomography; machine learning; analytic interpolation; delay systems; Inversa problem; konvex optimering; variationell regularisering; trigonometriska momentproblem; optimal masstransport; datortomografi; maskininlärning; analytisk interpolation; system med tidsfördröjning; Matematik; Mathematics;

    Abstract : This thesis, which mainly consists of six appended papers, primarily considers a number of inverse problems in imaging and system identification.In particular, the first two papers generalize results for the rational covariance extension problem from one to higher dimensions. READ MORE

  3. 3. Variational Tensor-Based Models for Image Diffusion in Non-Linear Domains

    Author : Freddie Åström; Michael Felsberg; George Baravdish; Reiner Lenz; Christoph Schnörr; Linköpings universitet; []
    Keywords : NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; image diffusion; variational formulation; denoising; tensor; non-linear;

    Abstract : This dissertation addresses the problem of adaptive image filtering.Although the topic has a long history in the image processing community, researchers continuously present novel methods to obtain ever better image restoration results. READ MORE

  4. 4. Statistical Segmentation and Registration of Medical Ultrasound Data

    Author : Mattias Hansson; Matematik LTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Registration; Segmentation; Feature descriptor; Statistical image and signal processing; Medical ultrasound; Variational methods; Mixture model; Bayesian; Markov Chain Monte Carlo; Similarity measur;

    Abstract : The interpretation of ultrasonic imagery is typically not straightforward and of quite subjective nature and therefore strongly dependent on the expertise of its users. Thus the development of algorithms which aid in the interpretation of ultrasonic data is a highly relevant topic. READ MORE

  5. 5. Inverse Mathematical Models for Brain Tumour Growth

    Author : Rym Jaroudi; George Baravdish; Tomas Johansson; Trucu Dumitru; Linköpings universitet; []

    Abstract : We study the following well-established model of reaction-diffusion type for brain tumour growth:This equation describes the change over time of the normalised tumour cell density u as a consequence of two biological phenomena: proliferation and diffusion.We discuss a mathematical method for the inverse problem of locating the brain tumour source (origin) based on the reaction-diffusion model. READ MORE