scholarly journals On hybrid convolution quadrature approaches for modelling time‐domain wave problems with broadband frequency content

2021 ◽  
Author(s):  
Jacob Rowbottom ◽  
David J. Chappell
Keyword(s):  
Time Domain ◽  
Frequency Content ◽  
Convolution Quadrature ◽  
Wave Problems ◽  
Broadband Frequency

Analysis of Convolution Quadrature Applied to the Time-Domain Electric Field Integral Equation

2012 ◽  
Vol 11 (2) ◽  
pp. 383-399 ◽  
Author(s):  
Q. Chen ◽  
P. Monk ◽  
X. Wang ◽  
D. Weile
Keyword(s):  
Integral Equation ◽  
Electric Field ◽  
Time Domain ◽  
Electromagnetic Scattering ◽  
Optimal Order ◽  
Electric Field Integral Equation ◽  
Optimal Order Of Convergence ◽  
Convolution Quadrature ◽  
The Time Domain ◽  
Field Integral

AbstractWe show how to apply convolution quadrature (CQ) to approximate the time domain electric field integral equation (EFIE) for electromagnetic scattering. By a suitable choice of CQ, we prove that the method is unconditionally stable and has the optimal order of convergence. Surprisingly, the resulting semi discrete EFIE is dispersive and dissipative, and we analyze this phenomena. Finally, we present numerical results supporting and extending our convergence analysis.

scholarly journals Hydrological model performance and parameter estimation in the wavelet-domain

2009 ◽  
Vol 6 (2) ◽  
pp. 2451-2498 ◽  
Author(s):  
B. Schaefli ◽  
E. Zehe
Keyword(s):  
Time Series ◽  
Parameter Estimation ◽  
Time Domain ◽  
Model Performance ◽  
Time Varying ◽  
Wavelet Domain ◽  
Frequency Content ◽  
Time Varying Frequency ◽  
The Time Domain

Abstract. This paper proposes a method for rainfall-runoff model calibration and performance analysis in the wavelet-domain by fitting the estimated wavelet-power spectrum (a representation of the time-varying frequency content of a time series) of a simulated discharge series to the one of the corresponding observed time series. As discussed in this paper, calibrating hydrological models so as to reproduce the time-varying frequency content of the observed signal can lead to different results than parameter estimation in the time-domain. Therefore, wavelet-domain parameter estimation has the potential to give new insights into model performance and to reveal model structural deficiencies. We apply the proposed method to synthetic case studies and a real-world discharge modeling case study and discuss how model diagnosis can benefit from an analysis in the wavelet-domain. The results show that for the real-world case study of precipitation – runoff modeling for a high alpine catchment, the calibrated discharge simulation captures the dynamics of the observed time series better than the results obtained through calibration in the time-domain. In addition, the wavelet-domain performance assessment of this case study highlights which frequencies are not well reproduced by the model, which gives specific indications about how to improve the model structure.

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