Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 107 for “"Forward model"”.
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A finite difference forward model for MEG and EEG
In this thesis, I designed and implemented a model of the electromagnetic signals generated by the human brain as seen on magnetoencephalography and electroencephalography machines. The model makes a novel use of the principle of reciprocity combined with Ohm's Law and the Biot Savart Law to build …
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A forward model-based analysis of cardiovascular system identification methods
… based on a test bed of data generated from a forward model of the cardiovascular system whose dynamical properties are known. To this end, we developed a computer model of the human cardiovascular system which includes a lumped parameter model of the heart and circulation and a model of the …
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A forward model for ionospheric soundings and its use with incoherent scatter radar data to obtain ionospheric plasma density profiles
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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A forward model for ionospheric soundings and its use with incoherent scatter radar data to obtain ionospheric plasma density profiles
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2022-11-11 without embargo terms
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Calibration of Jicamarca radar using F-region incoherent scatter for measurements of D-region backscatter RCS
… simulated power returns to the measurements. The forward model used in the calibration algorithm is based on magnetoionic theory, incoherent scatter radar theory, and antenna theory. Based on comparison with published results, as well as with crude estimates, we conclude that the forward model …
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Signal processing and image restoration techniques for two-dimensional eddy current nondestructive evaluation
… presents a comprehensive study on the forward modeling methods, signal processing techniques, and image restoration techniques for two-dimensional eddy current nondestructive evaluation. The basic physical forward method adopted in this study is the volume integral method. We have …
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The estimation and statistical inferences of the position and orientation of a scanning laser Doppler vibrometer
In this dissertation, two nonlinear regressive models, the forward model and the inverse model, have been developed to determine the pose (position and orientation) of the scanning laser Doppler vibrometer (SLDV) with respect to a structural coordinate system. The parameters in the forward model …
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The use of adjoint models for determining the sensitivity of integral quantities in an eddy resolving Oean General Circulation Model
Adjoint models calculate the exact sensitivity of an output function of a model to infinitesimal perturbations in the forcing or initial conditions. In eddy resolving ocean models the presence of chaotic eddies is expected to lead to sensitivities to infinitesimal perturbations that are very …
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A GEOMETRIC VARIATIONAL APPROACH TO SHAPE INVERSION FOR RADAR
… seeks to match the received signal to a computed forward model based on the evolving shape. Adopting such an approach comes with important advantages such as the ability to naturally embed the shape priors into the estimation and being able to model self-occlusions which cannot be easily …
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Forward and Inverse Modeling of Tsunami Sediment Transport
… both tsunami frequency and magnitude. Numerical modeling of sediment transport during a tsunami is important interdisciplinary research to estimate the frequency and magnitude of past events and quantitative prediction of future events. The goal of this dissertation is to develop robust, …
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Multifocal interferometric synthetic aperture microscopy
… the solution of the inverse problem to the forward model for each channel. A general regularized solution eliminates artifacts that affect multibeam OCT while achieving better signal-to-noise ratio over the entire image than is possible with single-focus ISAM. We present detailed theory, …
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Advanced parallel magnetic resonance imaging methods with applications to MR spectroscopic imaging
… large number of small receivers. A generalized forward model and inverse reconstruction with regularization for parallel MRI with arbitrary k-space sub-sampling is developed. Regularization methods using the singular value decomposition of the encoding matrix and pre-conditioning of the forward …
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Robust Machine Learning Methods in Solving Inverse Problems
… to lack interpretability and physical grounding. Model-based architectures such as loop unrolling (LU) draw inspiration from optimization by unrolling the iterative updates for an optimization-based solver and then learning a regularizer from data. These architectures are the current …
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A Compressed Sensing Approach to Detect Immobilized Nanoparticles Using Superparamagnetic Relaxometry
… we calibrated the sensor locations used in the forward model to measured data, and found a 5% agreement between the forward model and the data. Next, we determined the optimal choice of the data fidelity parameter and investigated the effect of experimental factors on the reconstruction. …
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Randomization for Efficient Nonlinear Parametric Inversion
… locate tumors in the body. Using a mathematical (forward) model to predict measurements given a parametrization of the tissue, we minimize the misfit between predicted and actual measurements up to a given noise level. The main computational bottleneck in such inverse problems is the repeated …
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Bayesian Damage Identification from Elastostatic Data
… and observation error are explicitly taken and modelled as jointly distributed random variables. One of the advantages of the Bayesian framework is that it can quantify the uncertainty of a point estimate for the unknown, unlike the deterministic framework. The problem of damage identification …
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Computational and laboratory investigations of a model of blood droplet flight for forensic applications
We present a three-dimensional, forward model of blood droplets in ight. The proposed model is based on a set of ordinary di erential equations (ODEs) incorporating viscous drag and gravitational forces. We validate the model against laboratory experiments in which a mock crime scene is …
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A Bayesian Approach to Spike Sorting of Neural Data via Source Localization
… first is the usage of a dipole-based generative model for recorded waveforms. This dipole approximation of a neuron, which captures the empirical falloff in signal strength with distance from the probe, allows us to estimate the position from which signals originate. This in turn helps us …
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Kinematic and flexural isostasy modeling in central nepal: using erosional, depositional, and cooling histories to validate a balanced cross section
… geometry, allowing the production of a kinematic forward model of deformation beginning with the original pre-deformation geometry. I produced a new balanced cross section in central Nepal through the Himalayan thrust belt from hinterland to foreland and forward modeled the cross section in 2D …
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A nonlinear least squares inversion to the single-scattering three-dimensional radiative transfer equation for satellite-based tomography
A major uncertainty in weather and climate models lies in the effect of clouds and aerosols. The IPCC's Fifth Assessment Report states that while models include more cloud and aerosol processes, there is still low confidence in the representation and quantification of the processes in climate …
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