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.
Results
Showing 1 to 20 of 26 for “"level set methods"”.
-
Level set methods for higher order evolution laws
… geometric evolution equations with the level set and the finite element method is presented. The isotropic, weak anisotropic and strong anisotropic situation is discussed. Most of the equations considered in this work arise from the field of thin film growth. A short introduction to the …
-
Path planning in time dependent flows using level set methods
… and dynamics investigation. Gliders exhibit high levels of autonomy and are ideal for long range missions. As these gliders become more reliable and affordable, multi-vehicle coordination and sampling missions are expected to become very common in the near future. This endurance of gliders …
-
Development of level set methods for computing the semiclassical limit of Schrödinger equations with potentials
<p>In this thesis, several level set methods are developed and analyzed for computing multi-valued solutions to the semiclassical limits of Schroedinger equations. Both formulation and numerical results are obtained for level set method. Superposition is also proved via let set method setting. …
-
Applicability of hybrid methods in engine control system design
… of off-line model predictive control and level set methods have been applied to the challenges of engine management for diesel exhaust aftertreatment. Theoretical work has been supported by experiments carried out in a diesel engine test cell. A control relevant air-path model was …
-
Fast Marching Methods - parallel implementation and analysis
… evolving with normal velocity F>0. Fast Marching Methods are a necessary step in Level Set Methods, which are widely used today in scientific computing. The classical Fast Marching Methods, based on finite differences, are typically sequential. Parallelizing Fast Marching Methods is a step forward …
-
Fast Path Planning in Uncertain Environments: Theory and Experiments
… control path planning algorithm that is based on level-set methods. The hybrid method uses global or local level sets in the formulation of the receding horizon control problem. The decision to select a new level set is made based on certain matching conditions that guarantee the optimality of the …
-
Modeling Collective Behavior of Dislocations in Crystalline Materials
… equations governing geometric optics and level set methods in the following physical contexts: annihilation of dislocations, expansion of a polygonal dislocation loop and operation of a Frank-Read source. The weak solutions to these equations are not unique, and the numerical method is …
-
Nonlinear simulation of tumor growth and chemotherapy
… develop new finite difference and ghost fluid / level set methods to attain full second-order accuracy for the first time in the context of afully-coupled, nonlinear moving boundary problem. Our new methods include a robust boundarycondition-capturing Poisson solver, improved discretizations of …
-
Interface-Tracking by the Face-Offsetting Method for Martensitic Transformation Simulations
… front-tracking scheme called the face-offsetting method (FOM) In explicitly model phase interfaces. Results not only demonstrate the effectiveness of the FOM for resolving lenticular twinned microstructure with cusp-like tips but also question (a) the applicability of level-set methods for …
-
Level-Set Ghost Fluid Methods for Free Boundary Problems in Incompressible Euler and Navier-Stokes Equations
… per la discretizzazione temporale e metodi level-set per la rappresentazione dell'interfaccia. Il dominio è discretizzato su una griglia Cartesiana regolare. La frontiera, descritta mediante i metodi level-set, è vista come la curva di livello zero di una data funzione, chiamata funzione …
-
Frugal hypothesis testing and classification
… regularization and optimization via variational level set methods is developed. This novel classifier is termed the geometric level set (GLS) classifier. A method for joint dimensionality reduction and margin-based classification with optimization on the Stiefel manifold is developed. This …
-
Interactive specification and acquisition of depth from single images
… using the powerful notion of selection. Once a set of pixels is selected, the user can assign depth by painting and chiseling, using shape from shading, applying filters, aligning and extracting shape from geometry primitives, or using level set methods. The ground plane tool provides an …
-
Multiscale modeling of thin film deposition processes
… rates are combined with ballistic transport and level set methods. The resulting tool demonstrates the effect of the kinetic energy driven surface diffusion on the feature profile evolution. For the ECD process of copper, detailed surface kinetic mechanisms are developed based on the competitive …
-
Thermomechanical and Vibration Analysis of Stiffened Unitized Structures and Threaded Fasteners
… cutouts using single patch, multiple patches and level set methods is then discussed. A novel way to achieve displacement compatibility between the panel and stiffeners interfaces is introduced. An easy way of modeling plates with complicated cutouts by using edge curves and generating a ruled …
-
Adjoint-based optimization for hyperbolic balance laws in the presence of discontinuities
… in multiphase flows using discrete adjoint-based methods. The main issues we will endeavor to study are the impact on the linearized and adjoint equations of discontinuous solutions, the behavior of the THINC-family of numerical schemes under linearization and the rigorous formulation of an …
-
Time-Optimal Path Planning in the Portugal-Azores-Madeira Ocean Region
… schemes based on exact Hamilton–Jacobi PDE and Level Set methods to predict time-optimal trajectories. This approach allows for multiple applications in optimal path planning for autonomous vehicles in the ocean and coastal environment. Employing our multi-resolution ocean modeling and data …
-
Diffusion Tensor Imaging: Evaluation of Tractography Algorithm Performance Using Ground Truth Phantoms
… (FMT) algorithms based on fast marching level set methods have been proposed to better handle the presence of IVOH in DTI data when compared to older Streamline Tractography (SLT) methods. However, the actual performance advantage of any tractography algorithm over another cannot be …
-
Reachability prediction and optimal path planning for autonomous ocean vehicles
… In this thesis, we employ the Massachusetts Institute of Technology – Multidisciplinary Simulation, Estimation, and Assimilation Systems (MIT-MSEAS) time-optimal and hazard-time-optimal path planning theory and schemes based on exact Hamilton–Jacobi partial differential equations (PDEs) …
-
Interfaces in Numerical Relativistic hydrodynamics
… interface between two fluids, modelled<br/>using level set methods, have been developed. These techniques lend<br/>themselves naturally to an extension to the relativistic situations we wish to<br/>consider. In this thesis we start from the Ghost Fluid Method of Fedkiw et al.<br/>We first …
-
Toward computational oncology: nonlinear simulation of centimeter-scale tumour growth in complex, heterogeneous tissues
… tissue. We solve the model using a new level set/ghost fluid method that can produce accurate solutions on arbitrary domains, even when faced with challenging topological changes. This model provides a core framework for the development of more sophisticated models. After a brief …
Page 1 of 2