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 57 for “"Tikhonov"”.
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Extracting Ramachandran torsional angle distributions from 2D NMR data using Tikhonov regularization /
… stability of the inverse mapping is problematic. Tikhonov regularization is a well-known method of improving the stability of the inverse; in this work it is extended to use a new regularization functional based on the Laplacian rather than on the norm of the function itself. In this way, one …
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Probing localized states distributions in semiconductors by Laplace transform transient photocurrent spectroscopy
… procedure has been discussed.<br/><br/>The <i>Tikhonov </i>regularization method (Tikhonov A. N., 1963; Weese J., FTIKREG program, 1992), regarded as one of the most reliable methods for extracting information from noisy experimental data, has been applied to computer simulated data. It has …
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Source distribution analysis of magnetic microscopy maps of geological samples
… our investigation demonstrates that Tikhonov regularization with a high pass filter matrix performs better than unregularized least square methods, truncated singular value decomposition, and Tikhonov regularization using an identity matrix (minimum norm). Our study also gives insight …
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Contributions to regularization theory and practice of certain nonlinear inverse problems
… inverse problems. The first part considers Tikhonov regularization for nonlinear ill-posed operator equations in Hilbert scales with oversmoothing penalties. Sufficient as well as necessary conditions to establish convergence are introduced and convergence rate results are given for various …
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Everything old is new again : a fresh look at historical approaches in machine learning
… learning problems. We begin by considering Tikhonov regularization, a broad framework of schemes for binary classification. Tikhonov regularization attempts to find a function which simultaneously has small empirical loss on a training set and small norm in a Reproducing Kernel Hilbert …
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Hessian Matrix-Free Lagrange-Newton-Krylov-Schur-Schwarz Methods for Elliptic Inverse Problems
… optimization community. In this study, iterative Tikhonov and Total Variation regularizations are proposed and compared to the standard regularizations and each other. For exact data with jump discontinuities the standard and iterative Total Variation regulations are superior to the standard and …
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Optimal Control for an Impedance Boundary Value Problem
… within the framework of the minimization of a Tikhonov functional. In particular, questions of the existence of an optimal solution and the derivation of the optimality conditions will be addressed.
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Incorporating prior information into geophysical inversion: from regularized inversion of thermal data to a framework using conditional variational autoencoders
… thermal data are underexplored. I formulate Tikhonov inversion algorithms to recover continuously varying distributions of thermal conductivity from borehole temperature data and surface heat flow data. The naïve application of Tikhonov inversion produces unrealistically smooth models that …
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A semigroup approach to the numerical solution of parabolic differential equations
… classical theory, we present a modification of Tikhonov regularisation which is closely adapted to the eigenspaces of the ill-posed operator. While this eigenspaces are usually unknown, we develop an algorithm based on a contour integral which projects any given value onto certain selected …
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Quasistationarität und fast-invariante Mengen gewöhnlicher Differentialgleichungen
… via singular perturbation theory, particularly Tikhonov's theorem. Given a differential equation system of particular form, which depends on a small parameter, then Tikhonov's theorem provides (asymptotically) a reduction to smaller dimension. Fenichel's theorem deepens this result in a broader …
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Computational imaging through deep learning
… an estimate of the object by minimizing the Tikhonov functional, which requires explicit formulations of the forward operator of the physical system, as well as the prior knowledge about the class of objects being imaged. In recent years, machine learning architectures, and deep learning (DL) …
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The inverse medium problem for Timoshenko beams and frames : damage detection and profile reconstruction in the time-domain
… of profile multiplicity by means of either Tikhonov or Total Variation regularization. We report on numerical experiments using synthetic data that show satisfactory reconstruction of a variety of profiles, including smoothly and sharply varying profiles, as well as profiles exhibiting …
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Cultural Identity and Attenuated Psychotic Experiences
<p>Empirical research has shown an increased prevalence of psychosis among immigrant groups living in Westernized contexts. Cultural identity has been researched as a risk/protective factor for psychosis; however no consistent result has emerged. Cultural identity captures an individuals’ sense of …
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The Rise of Insider Iconography: Visions of Soviet Turkmenia in Russian-Language Literature and Film, 1921-1935
… World, 1926) and two literary works by Nikolai Tikhonov, a "fellow traveler" who passed through Turkmenistan in the mid-1920s. Despite the differences in the approaches of the Eurasianists, Vertov, and Tikhonov, I argue, all of these men envisioned Turkmenia as an undelimited space within a …
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Anwendung des Mikrogravitationslinseneffekts zur Untersuchung astronomischer Objekte
… besser angepasst ist als die bisher verwendete Tikhonov-Phillips-Regularisierung. Es zeigt sich, dass mit dieser Methode eine bessere Rekonstruktion kleinerer Strukturen in der Quelle möglich ist. Weiterhin wird die Anwendbarkeit der Regularisierungsmethode auf realistische Lichtkurven mit …
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Recovering signals in physiological systems with large datasets
… noisy data. The first method is an extension of Tikhonov regularization to large-scale problems, using a sequential update approach. In the second method, we improve the conditioning of the problem by assuming that the input is uniform over a known time interval, and then we use a least-squares …
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A critical analysis of the 2H NMR data in chlorhexidine-containing model membranes
… bulk lipids in the membrane. The study used a Tikhonov-regularization-based numerical deconvolution technique (dePakeing) that allowed simultaneous determination of the order parameter and of the orientational distribution of domains in the powder sample, partially oriented by the external …
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Intelligent Monitoring of Powerline Vibrations - Sparse Sensing and Predictive Modeling Approach
… Dynamic Mode Decomposition (DMD) with Tikhonov regularization for stable reduced-order modeling, and estimation algorithms such as Kalman and particle filters for reconstructing full-system states from sparse observations. A pivoted QR decomposition method is employed to determine …
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Asymptotic theory for Bayesian nonparametric inference in statistical models arising from partial differential equations
… posterior-based reconstruction corresponds to a Tikhonov regulariser with a reproducing kernel Hilbert space norm penalty. We prove a semiparametric Bernstein–von Mises theorem for a large collection of linear functionals of the unknown, implying that semiparametric posterior estimation and …
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