scholarly journals A Multilevel Algebraic Error Estimator and the Corresponding Iterative Solver with $p$-Robust Behavior

2020 ◽  
Vol 58 (5) ◽  
pp. 2856-2884
Author(s):  
Ani Miraçi ◽  
Jan Papež ◽  
Martin Vohralík
Keyword(s):  
Error Estimator ◽  
Iterative Solver ◽  
Algebraic Error

Improving Space-Time-Frequency MIMO-OFDM with ICI Self-Cancellation Scheme using Least Square Error Estimator

2015 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nur Farahiah Ibrahim ◽  
Zahari Abu Bakar ◽  
Azlina Idris
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Symbol Error Rate ◽  
Space Time ◽  
Least Square ◽  
Error Estimator ◽  
Frequency Diversity ◽  
Time Frequency ◽  
Mimo Ofdm ◽  
Subcarrier Mapping

Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.

scholarly journals Goal-Oriented Error Estimation for the Fractional Step Theta Scheme

2014 ◽  
Vol 14 (2) ◽  
pp. 203-230 ◽  
Author(s):  
Dominik Meidner ◽  
Thomas Richter
Keyword(s):  
Time Discretization ◽  
Posteriori Error ◽  
Numerical Dissipation ◽  
Error Estimator ◽  
Fractional Step ◽  
Weighted Residual Method ◽  
Time Stepping ◽  
Backward Euler ◽  
Galerkin Formulation ◽  
Theta Method

Abstract. In this work, we derive a goal-oriented a posteriori error estimator for the error due to time-discretization of nonlinear parabolic partial differential equations by the fractional step theta method. This time-stepping scheme is assembled by three steps of the general theta method, that also unifies simple schemes like forward and backward Euler as well as the Crank–Nicolson method. Further, by combining three substeps of the theta time-stepping scheme, the fractional step theta time-stepping scheme is derived. It possesses highly desired stability and numerical dissipation properties and is second order accurate. The derived error estimator is based on a Petrov–Galerkin formulation that is up to a numerical quadrature error equivalent to the theta time-stepping scheme. The error estimator is assembled as one weighted residual term given by the dual weighted residual method and one additional residual estimating the Galerkin error between time-stepping scheme and Petrov–Galerkin formulation.

An iterative solver for the 3D Helmholtz equation

2017 ◽  
Vol 345 ◽  
pp. 330-344 ◽  
Author(s):  
Mikhail Belonosov ◽  
Maxim Dmitriev ◽  
Victor Kostin ◽  
Dmitry Neklyudov ◽  
Vladimir Tcheverda
Keyword(s):  
Helmholtz Equation ◽  
Iterative Solver

Restricted model domain time Radon transforms

Geophysics ◽  
2016 ◽  
Vol 81 (6) ◽  
pp. A17-A21 ◽  
Author(s):  
Juan I. Sabbione ◽  
Mauricio D. Sacchi
Keyword(s):  
Inverse Problem ◽  
Seismic Data ◽  
Computational Cost ◽  
Synthetic Data ◽  
Model Space ◽  
Radon Transforms ◽  
Iterative Solver ◽  
Hard Thresholding ◽  
Restricted Model ◽  
Marine Data

The coefficients that synthesize seismic data via the hyperbolic Radon transform (HRT) are estimated by solving a linear-inverse problem. In the classical HRT, the computational cost of the inverse problem is proportional to the size of the data and the number of Radon coefficients. We have developed a strategy that significantly speeds up the implementation of time-domain HRTs. For this purpose, we have defined a restricted model space of coefficients applying hard thresholding to an initial low-resolution Radon gather. Then, an iterative solver that operated on the restricted model space was used to estimate the group of coefficients that synthesized the data. The method is illustrated with synthetic data and tested with a marine data example.

A residual based error estimator using radial basis functions

2008 ◽  
Vol 44 (9-10) ◽  
pp. 631-645 ◽  
Author(s):  
Bernard B.T. Kee ◽  
G.R. Liu ◽  
G.Y. Zhang ◽  
C. Lu
Keyword(s):  
Radial Basis Functions ◽  
Basis Functions ◽  
Error Estimator ◽  
Radial Basis

scholarly journals Quantitative study of computing time of direct/iterative solver for MoM by GPU computing

2013 ◽  
Vol 2 (8) ◽  
pp. 359-364 ◽  
Author(s):  
Keisuke Konno ◽  
Hajime Katsuda ◽  
Kei Yokokawa ◽  
Qiang Chen ◽  
Kunio Sawaya ◽  
...  
Keyword(s):  
Quantitative Study ◽  
Gpu Computing ◽  
Computing Time ◽  
Iterative Solver
Sign in / Sign up

Export Citation Format

Share Document