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 270 for “"Diffusion model"”.
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Understanding Human Imagination Through Diffusion Model
… Core," a dedicated unit housing a modified diffusion model. This model allows high-level features of an object to be employed for tasks like recreating the original object or forming entirely new objects from existing features. The experimental simulation, conducted with an Artificial Neural …
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The dual jump diffusion model for security prices
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1993.
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Telecommunications Technology Transfer/Diffusion Model Into Rural South Africa
… play a major role. Therefore transfer models that neglect these aspects often cause ineffective utilization of technology. Telecommunication technology transfers between two parties at different hierarchical levels of technology know-how/utilization (as between multi-national companies …
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Forecasting Twitter topic popularity using bass diffusion model and machine learning
… about by a large number of users. Predicting the diffusion process of a Twitter topic is meaningful for a company to forecast demand, and plan ahead to dispatch its products. In this study, we collected Twitter data on 220 topics, covering a wide range of fields. And we created 12 features for …
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A multiattribute utility diffusion model : Theory and application to the pre-launch forecasting of automobiles
Thesis (Ph. D.)--Massachusetts Institute of Technology, Sloan School of Management, 1984.
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An Energy Diffusion Model for Interior Acoustics with Structural Coupling Using the Laplace Transform Boundary Element Solution
… is a recently developed mathematical model for interior acoustics known as the acoustic diffusion model. The model extends statistical methods in high frequency acoustics to predict the spatial distribution of acoustic energy in the volume over time as a diffusion process. Previously, …
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Thermal-infrared radiosity and heat-diffusion model for estimating sub-pixel radiant temperatures over the course of a day
… devoted to thermal-infrared radiosity and a heat-diffusion model used for predicting effective emissivity spectra and radiant temperatures for rough natural surfaces, which allows one to estimate discrepancies between effective and actual values. Computer model results are compared to analytic …
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Incorporating consumer resistance to innovation in a new product diffusion model: A new model and a simulation comparison with existing models
This dissertation proposes a new diffusion model for an innovation in durable goods markets and compares the model with four existing models. The distinctive feature of the new diffusion model is an explicit consideration of the competition between an existing product and a new product due to the …
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Distinguishing Medial Temporal Lobe and Prefrontal Cortex Contributions to Approach-Avoidance Conflict in Healthy Controls and Generalized Anxiety Disorder: Insights from Functional Magnetic Resonance Imaging and the Hierarchical Drift Diffusion Model
… Across translational rodent and human models, AA conflict has been associated with anxiety and is supported by a network of brain regions including the medial temporal lobe (MTL), striatum, and prefrontal cortex (PFC). This work, however, is limited in two respects. (1) Human models …
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Image and Optical Property Reconstruction From Noninvasive Measurements of Turbid Media, in Vitro and in Vivo: A Promising Method for Optical Mammography
… field, researchers were uncertain whether the diffusion model would be valid for a medium containing inhomogeneities. I, along with a handful of other researchers demonstrated that the diffusion model is accurate enough to include well behaved heterogeneous tissue models in which a number of …
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Modelling energy markets and pricing energy derivatives
… assessment of the popular methodologies for modelling the underlying spot price dynamics in energy markets. After a brief introduction in the alternative forms of derivation that may be used for speculative and risk management purposes in energy markets, we assess the performance of the …
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Parameter Estimation in the Advection Diffusion Reaction Model With Mean Occupancy Time and Boundary Flux Approaches
In this dissertation, we examine an advection diffusion model for insects inhabiting a spatially heterogeneous environment and moving toward a more favorable environment. We first study the effects of adding a term describing drift or advection toward a favorable environment to diffusion models for …
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The kinetics of liquid-liquid extraction of metals in a rotating diffusion cell. A rotating diffusion cell is used to study the rates of extraction of divalent transition metals by di-(2-ethylhexyl)-phosphoric acid and a sulphur analogue. A chemical-diffusion model describes the rate curves.
A rotating diffusion cell (RDC) has been used to study the kinetics of extraction of the transition metals cobalt (II), nickel (II), copper (II) and zinc (II) from sulphate solutions into either of two extractants held in n-heptane; di-(2-ethylhexyl) phosphoric acid (D2EHPA) or di-(2- ethylhexyl) …
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Unsupervised Compositional Image Decompositionwith Diffusion Models
… of the world. This paper introduces Decomp Diffusion, an unsupervised method for decomposing images into a set of underlying compositional factors, each represented by a different diffusion model. We demonstrate how each decomposed diffusion model captures a different factor of the scene, …
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Modeling the rates of lead and strontium uptake by zeolitized tuff from Rainier Mesa, Nevada Test Site, Nevada
… surface precipitation and Sr sorbs through diffusion, the data were modeled by a first order model and a diffusion model. The sorption of Pb(II), displaying rapid uptake by the zeolitized tuff, is described well by the first order model but the diffusion model cannot reproduce the fast …
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Advanced numerical methods for image denoising and segmentation
… and examined. These include the isotropic diffusion model, the anisotropic diffusion model (the P-M model), the fourth-order PDE model (the Y-K model), and the active contour model in image segmentation. Based on the analysis of behaviours of each model, some improvements are proposed. …
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Sensitivities in Option Pricing Models
… the difference between the solution of the model and the market observations. Efficient gradient based optimization requires accurate gradient estimation of the cost function. In this thesis we highlight the adjoint method for computing gradients of the cost function in the context of …
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Neutronics analysis for cylindrical assembly using Green's functions
… method for both one group and two group neutron diffusion. The analytic results for a two-dimensional cylindrical system are simplified by assuming a cosine flux shape in the horizontal direction. This assumption makes the flux in the horizontal direction a neutron sink term in the radial …
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Hybrid & electric vehicle technology and its market feasibility
… While previous research used the unmodified Bass diffusion model or Generalized Bass model in order to examine the adoption rate of EVs, through using Norton-Bass Model and inserting Generalized Bass Model into Norton-Bass Model, this study seeks to overcome the limitation of Bass diffusion model, …
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