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 33 for “"Forward Problem"”.
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Numerical simulations of the forward problem and compressive digital holographic reconstruction of weak scatterers on a planar substrate
TFT (Thin-film transistor) - LCD (Liquid-crystal display) is now widely used by the display industry for the reason that LCD is compact and light with very low power consumption; moreover, it has little or no flicker and no geometric distortion. However, small defects from the bottom layers could …
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Development of Methodologies for the Solution of the Forward Problem in Magnetic-Field Tomography (MFT) Based on Magnetoencephalography (MEG)
… of methodologies for the solution of the forward problem in Magnetic field Tomography based on Magnetoencephalography. Throughout the report full aspects of the accurate solution are discussed, including the development of algorithms and methods for realistic brain model, development of …
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Three dimensional modelling of Electrical Impedance Tomography
… systems andsolving the three dimensional Forward Problem numerically since this allows the possibility of modelling complex shapes. However, solving the Forward Problem analytically is still very attractive as an analytical solution does not depend on the way the domain has been meshed. …
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Interdigital dielectrometry sensor design and parameter estimation algorithms for non-destructive materials evaluation
… parameter estimation algorithms require solving forward and inverse problems of material property estimation. The forward problem implies calculation of the sensor admittance matrix as a function of geometry and material properties. The inverse problem, inherently more difficult than the forward …
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Laser diffraction particle sizing : sampling and inversion
The inverse problem of obtaining particle size distributions from observations of the angular distribution of near forward scattered light is reexamined. Asymptotic analysis of the forward problem reveals the information content of the observations, and the sources of non-uniqueness and instability …
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Parallel Methods for the Solution of Large-Scale Radiation and Inverse Scattering Problems
… DBIM requires repeated solutions of the forward problem to compute an image. With the linear complexity offered by the MLFMA forward solver, DBIM reconstructions proceed with greatly-reduced computation. This allows the solution of very large inverse-scattering problems.
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Guided Wave Actuation for Enhanced Damage Identification in Carbon Fiber Reinforced Polymer Material Using Electrical Resistance Tomography
… hybrid approach, numerical simulations of the forward problem that can predict the effect of wave actuation in a composite with delamination crack on ERT measurements are developed. Discontinuous Galerkin Spectral Element Methods were implemented for the numerical simulation of the wave …
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Purely optical tomography : atlas-based reconstruction of brain activation
… approach for a more accurate solution of the DOT forward problem. Moreover, we outline the benefits and applicability of a Diffusion Approximation-based faster forward model solver. We also describe a new registration algorithm based on superficial landmarks which is an essential tool for the …
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Computational Solution Of Inverse Problems With Simulated Annealing
The examination of inverse problems represents a fascinating, diverse and difficult area of study. Almost any problem in mathematics, physics and engineering has an associated inverse problem. The method of quasi-solutions allows one to reformulate inverse problems as a function minimization …
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Data-driven Methods in Mechanical Model Calibration and Prediction for Mesostructured Materials
… material distribution pattern. The optimization problem can be divided into a forward problem focusing on accurate predication and an inverse problem focusing on efficient search of the optimal design. In the forward problem, the physical behavior of the material can be modeled based on …
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Uncertainty Quantification, State and Parameter Estimation in Power Systems Using Polynomial Chaos Based Methods
… response of the power system. Facing this problem, traditional methods, such as the Monte Carlo method and the Perturbation method, are either too time consuming or suffering from the strong nonlinearity in the system. To solve these, this Dissertation will mainly focus on developing the …
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Ambient seismic noise imaging using trans-dimensional and machine learning techniques with application to Borneo and Iceland
… network emulator for the one step inversion forward problem in order to greatly improve computational efficiency, thus making time-consuming inversion methodologies, such as Bayesian McMC inversions, more tractable. I build and train this emulator from a set of synthetic data sampled from a …
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Estimation of sea surface wave spectra using acoustic tomography
… coherence measured in the FRAM N experiment. The forward problem of computing the acoustic phase and travel time perturbation spectra given the surface wave spectrum is solved to first order. An application of the technique to ray phase data taken during the MIZEX '84 experiment is shown. The …
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On the foldability of rigid origami
… These challenges can be classified into the "forward problem'', which is the useful sufficient and necessary condition for a rigid origami with certain crease pattern to be foldable; and the "inverse problem'', which is to systematically design a rigid origami based on some targets, such as …
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Electrocardiographic Consequences Of Electrical And Anatomical Remodeling In Diabetic And Obese Humans
… transmembrane potentials: TMPs) and BSPs. The Forward-Problem Module of the platform calculates BSPs from a bidomain-model of myocyte TMPs and torso anatomy. The platform also contains a Cardio-myocyte TMP Estimation Module in which an innovative method, named regularized waveform …
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The Science of Mind Reading: New Inverse Optimal Control Framework
… actions result from solving an optimal control problem. We consider a naturalistic task to study this in greater detail, under a formal optimal control framework of Partially Observable Markov Decision Processes. In our "firefly" task, monkeys are trained to steer to catch transiently visible …
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Towards molecular reconstruction in Coulomb explosion imaging
… components to the approach examined here: the forward and the backward (inverse) problems. In the forward problem, we develop a model using the classical equations of motion to describe the time evolution of the constituent ions immediately after the fragmentation of the parent molecule. The …
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Monte Carlo solution to the inverse problem of ultrasonic defect characterisation
An important problem in the non-destructive testing of materials is the accurate determination of the location, size, shape and orientation of any detected flaws; this is essential for assessing integrity of inspected objects. This thesis presents a novel algorithm wherein recovery of the geometric …
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Adjoint-based optimization for hyperbolic balance laws in the presence of discontinuities
… and the rigorous formulation of an optimization problem when the interface is represented by a Heaviside marker function. We will study the two main discontinuous wave patterns that appear in hyperbolic balance laws: contact discontinuities and shocks. These two have very different …
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Electrical Impedance Tomography/Spectroscopy (EITS): a Code Division Multiplexed (CDM) approach
… process involves the numerical solutions of the forward problem; using Finite Element solvers and the resulting ill-posed inverse problem using iterative Optimization or Computational Intelligence methods. This method has applications mainly in the Biomedical imaging and Process monitoring …
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