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Showing 1 to 13 of 13 for “"variational techniques"”.
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Exact and variational investigations of Hubbard rings
… in the atomic limit of no intersite hopping, and variational techniques to obtain a lower bound for the ground state energy. From the Lieb-Wu equations we derive an exact expression for the ground state energy in the atomic limit. We obtain our result by exploiting the spin symmetry of the Hubbard …
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Supercritical Semi-Linear Elliptic Problems Using Variational Principles
The thesis investigates the use of variational methods to study elliptic partial differential equations (PDEs) with supercritical nonlinearities. By focusing on convex subsets of a Banach space, the research overcomes compactness issues typically encountered with nonlinearities that exceed the …
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On Stability and Evolution of Solutions in General Relativity
… of the Einstein field equations in terms of variational techniques borrowed from geometric analysis. These equations yield the evolution equations for the Cauchy problems of both general relativity and low energy string theory. We then proceed to investigate the evolutionary linear stability …
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Hidden state models for time series
… intractable and we show how to make use of variational techniques for approximating the posterior distribution over the hidden state variables. Experimental simulations on synthetic and real-world data demonstrate the application of dynamical local models for segmenting a time series into …
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Variational Methods in Ice Sheet Modelling
… that lead to these approximations. We develop a variational principle for Stokes flow, and neglect certain components in order to obtain the variational principle for the first-order approximation for ice flow. This result is fundamentally the result of assuming bed slopes to be much less than …
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Variational Methods in Ice Sheet Modelling
… that lead to these approximations. We develop a variational principle for Stokes flow, and neglect certain components in order to obtain the variational principle for the first-order approximation for ice flow. This result is fundamentally the result of assuming bed slopes to be much less than …
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Aggregated Learning: An Information Theoretic Framework to Learning with Neural Networks
Deep learning techniques have achieved profound success in many challenging real-world applications, including image recognition, speech recognition, and machine translation. This success has increased the demand for developing deep neural networks and more effective learning approaches. The aim of …
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Bioimaging of animal embryogenesis: mathematical methods and computational algorithms
… shapes are reconstructed by using PDEs based variational techniques such as the Subjective Surfaces and the Chan Vese method. Cells tracking is performed by combining informations previously detected on cells shape and position with biological regularization constraints. Our results are …
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A variational approach to hadron structure in lattice QCD
… computation. Over the past decade, the use of variational techniques has provided an effective framework for spectroscopic studies of the full hadron spectrum. Herein we generalise the use of the variational approach to hadron form factor calculations and examine its use in a number of …
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Magnetic Stability Analysis for the Geodynamo
… the success of more generalised stability techniques applied to the transition to turbulence in various non-magnetic fluid dynamical problems, we investigate both the onset of and subsequent maximised transient growth of magnetic energy. These approaches differ from the eigenvalue …
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Advanced Sampling Methods for Solving Large-Scale Inverse Problems
Ensemble and variational techniques have gained wide popularity as the two main approaches for solving data assimilation and inverse problems. The majority of the methods in these two approaches are derived (at least implicitly) under the assumption that the underlying probability distributions are …
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New contributions on motion estimation through optical flow techniques applied to cardiac magnetic resonance imaging = Nuevas contribuciones en estimación de movimiento mediante técnicas de flujo óptico aplicado a imagen de resonancia magnética cardiaca
… imaging sequences, based on optical flow techniques. The starting point has been the frequency-based methods biologically inspired and the differential methods based on a variational approach. The first method proposed is based on a spatiotemporal-frequency (STF) approach. More …