Sökning: "variational approaches"

Visar resultat 6 - 10 av 23 avhandlingar innehållade orden variational approaches.

  1. 6. Static and Dynamic Correlation Effects in Atoms

    Författare :Nils-Erik Dahlen; Matematisk fysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; magnetic and optical properties; electrical; Condensed matter:electronic structure; relaxation; magnetic resonance; supraconductors; spectroscopy; Kondenserade materiens egenskaper:elektronstruktur; Atom- och molekylärfysik; Atomic and molecular physics; spektroskopi; magnetisk resonans; egenskaper elektriska; supraledare; magnetiska och optiska ; variational energies; double ionization; Electron correlation; laser-atom interaction; Fysicumarkivet A:2002:Dahlen; conserving approximations; Green s functions; GW-approximation;

    Sammanfattning : The thesis considers the effects of electron correlation by studying the two opposite limits of atoms in the ground state and atoms in strong laser pulses. Computational methods and theoretical approaches differ significantly due to the different physical processes that are studied in these two cases. LÄS MER

  3. 7. The fW-mean filter framework for topology optimization and analysis of Friedrichs systems

    Författare :Linus Hägg; Martin Berggren; Eddie Wadbro; Björn Engquist; Umeå universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; topology optimization; filters; mathematical morphology; size control; minimum compliance problem; Friedrichs systems; well-posedness; variational formulations; linearized Euler’s equations; Galbrun’s equation; acoustics; Mathematics; matematik;

    Sammanfattning : Part I. Topology optimization is the most general form of design optimization in which the optimal layout of material within a given region of space is to be determined. Filters are essential components of many successful density based topology optimization approaches. LÄS MER

  4. 8. Data-driven Approaches to Uncertainty Modelling for SLAM in the Open Sea

    Författare :Ignacio Torroba; John Folkesson; Patric Jensfelt; John Leonard; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Datalogi; Computer Science;

    Sammanfattning : Autonomous underwater vehicles (AUVs) equipped with multibeam echo-sounders have become indispensable tools for bathymetric mapping due to their ability to reach seabed regions inaccessible to surface vessels. However, the closer proximity to the survey area comes at the expense of a growing error in the AUV global pose estimate due to the lack of prior maps or a geo-referencing system underwater, such as GPS. LÄS MER

  5. 9. Bayesian learning of structured dynamical systems

    Författare :Riccardo Sven Risuleo; Håkan Hjalmarsson; Johan Schoukens; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; system identification; bayesian learning; machine learning; Gaussian processes; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : In this thesis, we propose some Bayesian approaches to the identificationof structured dynamical systems. In particular, we consider block-orientedmodels in which a complex system is built starting from simple linear andnonlinear building blocks. LÄS MER

  7. 10. Prediction Methods for High Dimensional Data with Censored Covariates

    Författare :Caroline Svahn; Oleg Sysoev; Mattias Villani; Fredrik Gunnarsson; Xavier de Luna; Linköpings universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; statistics; machine learning; censored covariates; statistik; maskininlärning; censurerade kovariater;

    Sammanfattning : While access to data steadily increases, not all data are straight-forward to use for prediction. Censored data are common in several industrial scenarios, and typically arise when there are some limitations to measuring equipment such as for instance concentration measuring equipment in chemistry or signal receivers in signal processing. LÄS MER