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 41 for “"variational approach"”.
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A variational approach to MR bias correction
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2003.
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A GEOMETRIC VARIATIONAL APPROACH TO SHAPE INVERSION FOR RADAR
… To this end, we use a deformable shape evolution approach which 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 …
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A variational approach to hadron structure in lattice QCD
… allows for a first principles, non-perturbative approach to studying the strong interaction, in a manner well suited to numerical computation. Over the past decade, the use of variational techniques has provided an effective framework for spectroscopic studies of the full hadron spectrum. Herein …
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A variational approach to local optimality in control theory
A new approach to control theory is investigated in this thesis. The approach is based on a locally specified state space model of the control dynamics; together with a goal function, which defines a generalized distance from each state position to the desired equilibrium point or trajectory. A …
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A Variational Approach to Estimating Uncertain Parameters in Elliptic Systems
… is rarely known. In this thesis, we propose a variational approach to solve the stochastic inverse problem of obtaining a statistical description of the diffusion coefficient in an elliptic partial differential equation, based noisy measurements of the model output. We formulate the parameter …
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A study of relativistic fluids with applications to cosmology: A variational approach
… examines relativistic fluids. We have used the variational approach to develop tools for studying the dynamics of relativistic fluids to apply this to cosmological modelling. Studies like these go beyond the standard model in cosmology. Researchers believe that such extensions to the standard …
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A variational approach for the calculation of resonance escape probabilities in slab lattices
… for oxygen scattering and is derived by using a variational approach. A computer code for calculating resonance escape probabilities in slab lattices has been developed. The results are in agreement with those obtained by Corngold.
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Variational approach to solving the phonon Boltzmann transport equation for analyzing nanoscale thermal transport experiments
… conduction regime. In this thesis, we develop a variational approach to solving the BTE, appropriate for different experimental configurations, such as transient thermal grating (TTG) and time-domain thermoreflectance (TDTR). We provide an efficient and general methodology to solving the BTE and …
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Assimilation of Meteosat Second Generation (MSG) satellite data in a regional numerical weather prediction model using a one-dimensional variational approach
… is assessed by means of a one dimensional variational algorithm. The study is performed with the aim of improving the spatial and temporal resolution of available observations to feed analysis systems designed for high resolution regional scale numerical weather prediction (NWP) models. The …
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Métodos variacionais em problemas de termoelasticidade acoplada
… velop the teory of the problem, later we plana variational approach of the equations, afterward we are going to obtain numerical results with support of the finite elements method.
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Análise dinâmica de placas sandwich comprimidas simplesmente apoiadas
… The equations of motion were obtained through a variational approach. The changes in the natural frequencies and stability loads were analyzed according to the variations of the shear stiffness of the plate. The results were plotted and are included in this dissertation. lt was also plotted a …
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Covariant thermodynamics & relativity
… The present work builds on the multi-fluid variational approach to relativistic dissipation, pioneered by Carter, and provides a dynamical theory of heat conduction. The novel property of such approach is the thermodynamic interpretation associated with a two-fluid system whose constituents …
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A tensor product decomposition of the many-electron Hamiltonian
A new direct full variational approach is described. The approach exploits a tensor (Kronecker) product construction of the many-electron Hamiltonian and has a number of computational advantages. Explicit assembly and storage of the Hamiltonian matrix is avoided by using the Kronecker product …
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COMBINING QUANTUM TRAJECTORIES AND TIME-DEPENDENT VARIATIONAL MONTE CARLO FOR MANY-BODY OPEN QUANTUM SYSTEMS
… systems. This thesis introduces the Open-Time Variational Monte Carlo (otVMC) method, which combines the quantum trajectory formalism with Monte Carlo tech- niques to enable real-time simulations of open quantum systems. By exploiting stochas- tic Schrödinger equations and a variational …
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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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Rotation-Vibration States of Weakly Bound Linear Symmetric Triatomic Molecules: Helium-Hydride and Helium-Deuteride (Hamiltonian, Variation, Direct Coordinate Transformation)
… molecules are investigated by an ab initio variational approach with the Hamiltonian recently derived by Estes and Secrest through direct coordinate transformation method. Various forms of this Hamiltonian for a linear triatomic molecule are presented. The potential energy function for the …
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Vibrations of an isolated wind turbine blade using the finite element method
… subjected to nonsymmetric bending. Using a variational approach, a blade finite clement is developed from these equations of motion. Additionally, expressions are formulated for the elastic strain energy and kinetic energy of a rotating wind turbine blade. Lagrange's equation is applied to …
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Analytical perspectives on localized solutions of the phi-4 theory
… partial differential equation), the asymptotic approach does not capture the chaotic behaviour of the kink. Numerical simulations indicate that the chaotic motion of the kink is associated with the spontaneous emission of a small-amplitude breather. This observation motivates our subsequent …
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Understanding the Vibrational Features of Hydrogen-Bonded Dimers
… the potential energy surface and a quantum variational approach to calculate vibrational spectra from these surfaces. One of the methods developed involves adiabatically separating lower frequency vibrational modes, which modulate the hydrogen bond length, from higher frequency modes that …
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