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Partial Differential Equations Commons™
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- Allee effect (1)
- Convolution inequalities (1)
- Differential (1)
- Ductal carcinoma in situ (DCIS) model (1)
- Equations (1)
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- Free boundary problem (1)
- Functional analysis (1)
- Image (1)
- Interpolation (1)
- Inverse problem (1)
- Lattice differential equations (1)
- Lotka-volterra competition model (1)
- Nonlocal problem (1)
- Numerical solution (1)
- Parabolic equation (1)
- Partial (1)
- Partial differential equation (1)
- Partial differential equations (1)
- Protection zone (1)
- Reaction-diffusion (1)
- Reaction-diffusion model (1)
- Regularization (1)
- Segmentation (1)
- Sobolev space (1)
- Spreading speed (1)
- Traveling wave (1)
- Upper and lower solutions (1)
Articles 1 - 6 of 6
Full-Text Articles in Partial Differential Equations
Effects Of A Protection Zone In A Reaction-Diffusion Model With Strong Allee Effect., Isaac Johnson
Effects Of A Protection Zone In A Reaction-Diffusion Model With Strong Allee Effect., Isaac Johnson
Electronic Theses and Dissertations
A protection zone model represents a patchy environment with positive growth over the protection zone and strong Allee effect growth outside the protection zone. Generally, these models are considered through the corresponding eigenvalue problem, but that has certain limitations. In this thesis, a general protection zone model is considered. This model makes no assumption on the direction of the traveling wave solution over the Strong Allee effect patch. We use phase portrait analysis of this protection zone model to draw conclusions about the existence of equilibrium solutions. We establish the existence of three types of equilibrium solutions and the necessary …
Convolution Inequalities And Applications To Partial Differential Equations., Matthew Reynolds
Convolution Inequalities And Applications To Partial Differential Equations., Matthew Reynolds
Electronic Theses and Dissertations
In this dissertation we develop methods for obtaining the existence of mild solutions to certain partial differential equations with initial data in weighted L p spaces and apply them to some examples as well as improve the solutions to some known PDEs studied extensively in the literature. We begin by obtaining a version of a Stein-Weiss integral inequality which we will use to obtain general convolution inequalities in weighted L p spaces using the techniques of interpolation. We will then use these convolution inequalities to make estimates on PDEs that will help us obtain mild solutions as fixed points of …
Regularized Solutions For Terminal Problems Of Parabolic Equations., Sujeewa Indika Hapuarachchi
Regularized Solutions For Terminal Problems Of Parabolic Equations., Sujeewa Indika Hapuarachchi
Electronic Theses and Dissertations
The heat equation with a terminal condition problem is not well-posed in the sense of Hadamard so regularization is needed. In general, partial differential equations (PDE) with terminal conditions are those in which the solution depends uniquely but not continuously on the given condition. In this dissertation, we explore how to find an approximation problem for a nonlinear heat equation which is well-posed. By using a small parameter, we construct an approximation problem and use a modified quasi-boundary value method to regularize a time dependent thermal conductivity heat equation and a quasi-boundary value method to regularize a space dependent thermal …
Some Problems Arising From Mathematical Model Of Ductal Carcinoma In Situ., Heng Li
Some Problems Arising From Mathematical Model Of Ductal Carcinoma In Situ., Heng Li
Electronic Theses and Dissertations
Ductal carcinoma in situ (DCIS) is the earliest form of breast cancer. Three mathematical models in the one dimensional case arising from DCIS are proposed. The first two models are in the form of parabolic equation with initial and known moving boundaries. Direct and inverse problems are considered in model 1, existence and uniqueness are proved by using tool from heat potential theory and Volterra integral equations. Also, we discuss the direct problem and nonlocal problem of model 2, existence and uniqueness are proved. And approximation solution of these problems are implemented by Ritz-Galerkin method, which is the first attempt …
Spreading Speeds Along Shifting Resource Gradients In Reaction-Diffusion Models And Lattice Differential Equations., Jin Shang
Electronic Theses and Dissertations
A reaction-diffusion model and a lattice differential equation are introduced to describe the persistence and spread of a species along a shifting habitat gradient. The species is assumed to grow everywhere in space and its growth rate is assumed to be monotone and positive along the habitat region. We show that the persistence and spreading dynamics of a species are dependent on the speed of the shifting edge of the favorable habitat, c, as well as c*(∞) and c*(−∞), which are formulated in terms of the dispersal kernel and species growth rates in both directions. When …
Mathematical Hybrid Models For Image Segmentation., Carlos M. Paniagua Mejia
Mathematical Hybrid Models For Image Segmentation., Carlos M. Paniagua Mejia
Electronic Theses and Dissertations
Two hybrid image segmentation models that are able to process a wide variety of images are proposed. The models take advantage of global (region) and local (edge) data of the image to be segmented. The first one is a region-based PDE model that incorporates a combination of global and local statistics. The influence of each statistic is controlled using weights obtained via an asymptotically stable exponential function. Through incorporation of edge information, the second model extends the capabilities of a strictly region-based variational formulation, making it able to process more general images. Several examples are provided showing the improvements of …