Sökning: "error modeling"

Visar resultat 1 - 5 av 246 avhandlingar innehållade orden error modeling.

  1. 1. Computational Modeling of Complex Flows

    Författare :Johan Hoffman; Göteborgs universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; computational fluid dynamics; adaptive finite element method; a posteriori error estimate; subgrid modeling; transition to turbulence; multiresolution analysis; object-oriented software; computational fluid dynamics;

    Sammanfattning : In this thesis we consider the following aspects of computational modeling of complex flows: (i) subgrid modeling, (ii) stability, (iii) a posteriori error estimation, and (iv) computational platform. We develop a framework for adaptivity and error control for multiscale problems, in particular for turbulent flow, based on a posteriori error estimates. LÄS MER

  3. 2. A moving boundary problem for capturing the penetration of diffusant concentration into rubbers : Modeling, simulation and analysis

    Författare :Surendra Nepal; Adrian Muntean; Yosief Wondmagegne; Magnus Ögren; Karlstads universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Moving boundary problem; finite element method; a priori error estimate; a posteriori error estimate; order of convergence; diffusion of chemicals into rubber; swelling; Matematik; Mathematics;

    Sammanfattning : We propose a moving-boundary scenario to model the penetration of diffusants into rubbers. Immobilizing the moving boundary by using the well-known Landau transformation transforms the original governing equations into new equations posed in a fixed domain. LÄS MER

  4. 3. Modeling and Model Reduction in Automotive Systems

    Författare :Oskar Nilsson; Institutionen för reglerteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Automotive systems; Lambda sensor; Model reduction; Modeling; Engine air path;

    Sammanfattning : The current control design development process in automotive industry and elsewhere involves many expensive experiments and hand-tuning of control parameters. Model based control design is a promising approach to reduce costs and development time. In this process low complexity models are essential. LÄS MER

  5. 4. Linear Time-Varying Systems: Modeling and Reduction

    Författare :Henrik Sandberg; Anders Rantzer; Alexandre Megretski; Institutionen för reglerteknik; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; linear time-varying; model reduction; balanced truncation; error bounds; power converters; harmonics; periodic modeling; inverter locomotive; linear time-varying; model reduction; balanced truncation; error bounds; power converters; periodic modeling; harmonics; inverter locomotive;

    Sammanfattning : Linear time-invariant models are widely used in the control community. They often serve as approximations of nonlinear systems. For control purposes linear approximations are often good enough since feedback control systems are inherently robust to model errors. In this thesis some of the possibilities for linear time-varying modeling are studied. LÄS MER

  7. 5. Symmetrical FET Modeling

    Författare :Ankur Prasad; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; switch model; symmetrical model; nonlinear model; small-signal model; GaAs; Microwave FET; GaN;

    Sammanfattning : This thesis deals with empirical modeling of symmetrical Field-Effect Transistors (FETs). It covers three distinct topics within the areas of modeling and parameter extraction of microwave FETs.First, the symmetry of FET devices is addressed. Such devices are often used in transceivers as a building block for switches. LÄS MER