Sökning: "Local approximation"
Visar resultat 1 - 5 av 157 avhandlingar innehållade orden Local approximation.
1. Model Vertices Beyond the GW Approximation
Sammanfattning : We study the effects of local vertex corrections to the self energy of the electron gas. We find that a vertex derived from time-dependent density-functional theory can give accurate self energies without including the explicit time dependence of the exchange-correlation potential provided, however, that a proper decay at large momentum transfer (large q) is built into the vertex function. LÄS MER
2. Approximation of topology optimization problems using sizing optimization problems
Sammanfattning : The present work is devoted to approximation techniques for singular extremal problems arising from optimal design problems in structural and fluid mechanics. The thesis consists of an introductory part and four independent papers, which however are united by the common idea of approximation and the related application areas. LÄS MER
3. Numerical analysis for random processes and fields and related design problems
Sammanfattning : In this thesis, we study numerical analysis for random processes and fields. We investigate the behavior of the approximation accuracy for specific linear methods based on a finite number of observations. Furthermore, we propose techniques for optimizing performance of the methods for particular classes of random functions. LÄS MER
4. Privacy Mechanism Design Through the Lens of Information Theory : With Applications to Compression, Caching, and Semantic Communication
Sammanfattning : Privacy mechanism design is an important research area and is receiving increased attention in recent years. This field focuses on addressing the challenge of revealing general data that might have correlations with sensitive information, all while protecting this sensitive information against unauthorized access. LÄS MER
5. Contributions to Numerical Solution of Stochastic Differential Equations
Sammanfattning : This thesis consists of four papers: Paper I is an overview of recent techniques in strong numerical solutions of stochastic differential equations, driven by Wiener processes, that have appeared the last then 10 years, or so. Paper II studies theoretical and numerical aspects of stochastic differential equations with so called volatility induced stationarity. LÄS MER