Sökning: "time-domain"

Visar resultat 11 - 15 av 363 avhandlingar innehållade ordet time-domain.

  1. 11. Time-domain modelling of curve squeal: a fast model for one- and two-point wheel/rail contact

    Författare :Ivan Zenzerovic; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-point contact; non-Hertzian contact; dynamics coupling; rolling contact; tangential point-contact model; Curve squeal; time domain; frictional instability;

    Sammanfattning : Curve squeal is a type of railway noise that may arise when a railway vehicle negotiates a relatively tight curve. A single frequency, corresponding to a wheel mode, dominates the radiated sound, which makes squeal a very tonal noise. LÄS MER

  3. 12. A hybrid finite element method for electromagnetics with applications in time-domain

    Författare :DAVID DEGERFELDT; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Nitsche s method; antenna arrays; NASA almond; edge elements; scattering; explicit-implicit time-stepping; Maxwell s equations; Finite Element Method; mass lumping; stability analysis; Finite-Differences Time-Domain; periodic structures; shape and material optimization;

    Sammanfattning : In this thesis, a new hybrid method that combines the Finite Element Method (FEM) with the Finite-Difference in Time-Domain (FDTD) method is presented. Tetrahedrons in the unstructured FEM region are connected directly to thehexahedrons in the structured FDTD region. LÄS MER

  4. 13. Time-domain modeling of a wave power farm

    Författare :Charitini Stavropoulou; Uppsala universitet; []
    Nyckelord :;

    Sammanfattning : In this work, we model a point absorber wave energy converter (WEC) very similar to the device that originated and was developed at Uppsala University in Sweden. The device is simulated both as a one- and a two-body model. LÄS MER

  5. 14. Three-Dimensional Modelling and Inversion of DC resistivity and Time Domain EM data using Multi-Resolution Framework

    Författare :Jingyu Gao; Thorkild Maack Rasmussen; Maxim Smirnov; Bülent Tezkan; Luleå tekniska universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; DC Resistivity; time-domain electromagnetic; forward modelling; data inversion; Prospekteringsgeofysik; Exploration Geophysics;

    Sammanfattning : 3-D forward modelling and inversion techniques play an important role in data interpretation, but they are still computationally challenging tasks. Therefore, this thesis aims to improve forward modelling and inversion performance using novel multi-resolution (MR) grid approach. LÄS MER

  7. 15. Time-domain Reconstruction Methods for Ultrasonic Array Imaging : A Statistical Approach

    Författare :Fredrik Lingvall; Tadeusz Stepinski; Karl-Jörg Langenberg; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Signalbehandling; Ultrasonic array imaging; synthetic aperture imaging; maximum a posteriori estimation; linear minimum mean squared error estimation; SAFT; Bayesian image reconstruction; Signalbehandling; Signal processing; Signalbehandling; Signal Processing; signalbehandling;

    Sammanfattning : This thesis is concerned with reconstruction techniques for ultrasonic array imaging based on a statistical approach. The reconstruction problem is posed as the estimation of an image consisting of scattering strengths. LÄS MER