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 20 for “"Mean-field Model"”.
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Stochastic Mean-Field Polycrystal Plasticity Methods
… RCSR specimen which is not represented in our mean-field model.
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Aspects of superconductivity and fractionalization
… a number of experimental observations. A simple mean field model based on fractionalization ideas is proposed in this work which can possibly get around some of the drawbacks of the original fractionalization theory. Chapter one discusses various aspects of superconductivity along with BCS theory …
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Why it takes all kinds: diversity mechanisms and patterns in ecological communities
… is investigated. Three individual-based models are employed: 1) a meanfield differential equation model, 2) a simulation model of plant populations, and 3) a simulation model of interacting organisms.<br/><br/>The mean-field model is used to show that the traits of individuals in a …
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Predicting and identifying signs of criticality near neuronal phase transition
… anaesthesia. First, mathematical and electronic models of a single spiking neuron are investigated, focusing on stochastic subthreshold dynamics on close approach to spiking and to depolarisation-blocked quiescence (spiking death) transition points. Theoretical analysis of subthreshold neural …
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Ultracold Fermi gas with repulsive interactions
… was studied by simulating the Stoner model with a strongly interacting Fermi gas of ultracold atoms. We observed nonmonotonic behavior of lifetime, kinetic energy, and size for increasing repulsive interactions, which is in good agreement with a mean-field model for the ferromagnetic …
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Properties Of Nonlinear Randomly Switching Dynamic Systems: Mean-Field Models And Feedback Controls For Stabilization
… contains two parts. The first part focus on the mean-field models with state-dependent regime switching, and the second part focus on the system regularization and stabilization using feedback control. Throughout this dissertation, Markov switching processes are used to describe the randomness …
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The Surface Charge of Soft and Hard Sphere Colloidal Particles - Experimental Investigation and Comparison to Theory
… not be described by Poisson-Boltzmann based models. In the case of the trivalent counterions, we could experimentally verify the strong influence of counterion adsorption in the destabilization of the surface charged colloids. Furthermore, we showed that the zeta-potential is not suited for …
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Cyclic polymer liquid crystal structures.
… of the Metropolis Monte Carlo technique and a mean field calculation. Two models have been studied by the Monte Carlo technique in the NVT ensemble. In the first, each complete molecule was represented by a disc-like interactions potential and a tendency for the molecules to align in columns …
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Island nucleation and growth during submonolayer deposition
… propose a system of differential equations as a mean-field model of the submonolayer deposition of monomers onto a surface. A key feature of these equations is that they depend explicitly on a parameter known as the critical island size. We use rigorous and novel mathematical techniques to obtain …
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Avalanches in stars and at finite temperature
… observed in stars. We apply results from the mean field avalanche model to observations made by the \emph{Kepler} spacecraft and the VIRGO instrument, looking at several stars including our own Sun and Tabby's star. In this examination, we use the stars' light curve, their integrated flux as a …
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Lattice models of amphiphile and solvent mixtures.
… Carlo simulation of a three dimensional lattice model of an amphiphile and solvent mixture has been developed as an extension of earlier work in two dimensions. In the earlier investigation the simulation was carried out with three segment amphiphiles on a two dimensional lattice and cluster size …
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Avalanches in plastic deformation: maximum velocity statistics, finite temperature effects, and analysis of low time resolution data
… this thesis, we study the statistics of a simple mean-field avalanche model, with emphasis on both theoretical calculations and application to the analysis of experimental data on material deformation. We establish a relationship between the simple mean-field model and a continuous time model …
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Population-specific predictions for the finite Kuramoto model and collective synchronization in a system with resonant coupling
… of auto-oscillators is a comparatively new field of study. The first scientists to consider such problems were mathematical biologists, but applied mathematicians and physicists have made significant contributions as well. The chief model of synchronization of distinct auto-oscillators is …
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Dynamic weakening and trained memory in avalanche dynamics from high-entropy alloys to neurons and spin systems
… crystalline solids to neuronal networks and spin models. Despite differences in microscopic mechanisms, these systems share universal features such as broad event-size distributions and scale-invariant critical phenomena. A simple depinning theory provides a unifying framework for these behaviors, …
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Orientational fluctuations of liquid water at hydrophobic and hydrophilic interfaces
… interface. We present a statistical mechanical model of interfacial hydrogen bonding which is capable of predicting the orientational distribution at the interface. Using this model along with the atomistic simulations, we reveal that the hydrogen bonding interactions of non-ideal geometries are …
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Collective dynamics of evolving populations and their strategies with application to medicine
… between microbes and their viruses, we derive a mean-field theory for the population dynamics of microbe-virus systems, including the effects of lysogeny. In the absence of lysogeny, our model is a generalization of that proposed phenomenologically by Weitz and Dushoff. In the presence of …
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Investigation and Modelling of Fetal Sheep Maturation
… days of gestation), investigate three continuum models for electrical behaviour of the cortex, and tune the parameters in one of these models to generate the discontinuous EEG waves in the immature cortex. Visual inspection of the ECoG time-series shows that the third-trimester of fetal sheep is …
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Algorithms and Algorithmic Barriers in High-Dimensional Statistics and Random Combinatorial Structures
… combinatorial structures and of neural network models, with a particular emphasis on computational aspects. Our main contributions are summarized as follows. 1. Our first focus is on two algorithmic problems arising from the study of random combinatorial structures: the random number …
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Mechanical response of polyether polyurethane foams under multiaxial stress and the initial yielding of ultrathin films
… of elastic polyether polyurethane (EPP) foams by means of experiments, theory, and modeling. The experiments include five loading cases: uniaxial compression along the rise direction; uniaxial compression along two mutually perpendicular transverse directions; uniaxial tension along the rise …
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Model reduction of Markov chains with applications to building systems
Markov chain serves as an important modeling framework in applied science and engineering. e.g., Markov Chain Monte Carlo methods and Markov Decision Processes. A fundamental problem of Markov chain models is that the dimension of the problem could be very large in practice. This causes immense …