Sökning: "non-convex optimization"
Visar resultat 1 - 5 av 41 avhandlingar innehållade orden non-convex optimization.
1. Non-Convex Methods for Compressed Sensing and Low-Rank Matrix Problems
Sammanfattning : In this thesis we study functionals of the type \( \mathcal{K}_{f,A,\b}(\x)= \mathcal{Q}(f)(\x) + \|A\x - \b \| ^2 \), where \(A\) is a linear map, \(\b\) a measurements vector and \( \mathcal{Q} \) is a functional transform called \emph{quadratic envelope}; this object is a very close relative of the \emph{Lasry-Lions envelope} and its use is meant to regularize the functionals \(f\). Carlsson and Olsson investigated in earlier works the connections between the functionals \( \mathcal{K}_{f,A,\b}\) and their unregularized counterparts \(f(\x) + \|A\x - \b \| ^2 \). LÄS MER
2. Fast local optimization in decision analytic software
Sammanfattning : In decision analysis, significant recognition has been given to the fact that requiring numerically precise information seems unrealistic for real-life decision situations, Despite the emergence of many modern apporaches, which attempt to handle imprecise estimates, concentration has focused more on representation and less on evaluation. Methods such as the DELTA method challenged this issue by its evaluation framework that can accommodate both precision an imprecision, and thus pushes forward the disign of advanced dicision analysis systems. LÄS MER
3. Rank Reduction with Convex Constraints
Sammanfattning : This thesis addresses problems which require low-rank solutions under convex constraints. In particular, the focus lies on model reduction of positive systems, as well as finite dimensional optimization problems that are convex, apart from a low-rank constraint. LÄS MER
4. Contributions to Signal Processing for MRI
Sammanfattning : Magnetic Resonance Imaging (MRI) is an important diagnostic tool for imaging soft tissue without the use of ionizing radiation. Moreover, through advanced signal processing, MRI can provide more than just anatomical information, such as estimates of tissue-specific physical properties. LÄS MER
5. Numerical Algorithms for Optimization Problems in Genetical Analysis
Sammanfattning : The focus of this thesis is on numerical algorithms for efficient solution of QTL analysis problem in genetics.Firstly, we consider QTL mapping problems where a standard least-squares model is used for computing the model fit. LÄS MER