Sökning: "Optimal order methods"

Visar resultat 1 - 5 av 399 avhandlingar innehållade orden Optimal order methods.

1. 1. Optimal thinning : a theoretical investigation on individual-tree level

   Författare :Peter Fransson; Åke Brännström; Ola Lindroos; Oskar Franklin; Per Lundberg; Umeå universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; LANTBRUKSVETENSKAPER; AGRICULTURAL SCIENCES; Forest management; Simulation; Optimization; Spatially explicit model; Individual-based model;

   Sammanfattning : Paper I: In paper I, we asked how a tree should optimally allocate its resources to maximize its fitness. We let a subject tree grow in an environment shaded by nearby competing trees. The competitors were assumed to have reached maturity and had stopped growing, thus creating a static light environment for the subject tree to grow in. LÄS MER

3. 2. Convergence Analysis and Improvements for Projection Algorithms and Splitting Methods

   Författare :Mattias Fält; Institutionen för reglerteknik; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; First-order methods; Convex Optimization; Nonsmooth Optimization; Large-scale Optimization; Iterative Methods; Douglas-Rachford splitting; Line Search;

   Sammanfattning : Non-smooth convex optimization problems occur in all fields of engineering. A common approach to solving this class of problems is proximal algorithms, or splitting methods. These first-order optimization algorithms are often simple, well suited to solve large-scale problems and have a low computational cost per iteration. LÄS MER

4. 3. On Numerical Solution Methods for Block-Structured Discrete Systems

   Författare :Petia Boyanova; Maya Neytcheva; Oleg Iliev; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Preconditioning techniques; Finite element method; Two-by-two block matrices; Optimal order methods; AMLI method; Cahn-Hilliard equation; Multiphase flow; Inexact Newton method; Beräkningsvetenskap med inriktning mot numerisk analys; Scientific Computing with specialization in Numerical Analysis;

   Sammanfattning : The development, analysis, and implementation of efficient methods to solve algebraic systems of equations are main research directions in the field of numerical simulation and are the focus of this thesis. Due to their lesser demands for computer resources, iterative solution methods are the choice to make, when very large scale simulations have to be performed. LÄS MER

5. 4. Computational Diffusion MRI: Optimal Gradient Encoding Schemes

   Författare :Mohammad Alipoor; Chalmers tekniska högskola; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Gradient Encoding Scheme; ADC imaging; Diffusion MRI; D-optimal experiment design; Diffusion Tensor Imaging; Optimal Image acquisition; Second and Fourth Order Tensors.; Diffusion Kurtosis Imaging;

   Sammanfattning : Diffusion-weighted magnetic resonance imaging (dMRI) is a non-invasivestructural imaging technique that provides information about tissue microstructures.Quantitative measures derived from dMRI reflect pathologicaland developmental changes in living tissues such as human brain. LÄS MER

7. 5. Scalable Optimization Methods for Machine Learning : Acceleration, Adaptivity and Structured Non-Convexity

   Författare :Vien Van Mai; Mikael Johansson; John Duchi; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Large-scale optimization; Anderson acceleration; first-order methods; stochastic optimization; momentum; gradient clipping; Electrical Engineering; Elektro- och systemteknik;

   Sammanfattning : This thesis aims at developing efficient optimization algorithms for solving large-scale machine learning problems. To cope with the increasing scale and complexity of such models, we focus on first-order and stochastic methods in which updates are carried out using only (noisy) information about function values and (sub)gradients. LÄS MER