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 174 for “"Level set"”.
-
An Implicit Level Set Model for Firespread
<p>The level set method is a mathematical and computational, technique for tracking a moving interface over time. It can naturally handle topological changes such as merging or breaking interfaces. Intrinsic geometric properties of the interface, such as curvature and normal direction, are easily …
-
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 …
-
The Horizontal Tunnelability Graph is Dual to Level Set Trees
… of horizontal tunnelability. We prove that the level set tree gotten from its Harris Path (a time series), is dual to the time series' horizontal tunnelability graph, itself a subgraph of the more common horizontal visibility graph. This technique extends previous work by relating Merge, Chiral …
-
A Hybrid Variational-Level Set Approach to Handle Topological Changes
… are imminent. When a change occurs, we use a level set method to guide the change of topology of the domain mesh. This is then followed by an optimization step, using a variational formulation, that seeks to improve boundary mesh conformity to the zero level contour of the level set function. …
-
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 …
-
Energy optimal path planning using stochastic dynamically orthogonal level set equations
… rigorous a new stochastic Dynamically Orthogonal Level Set optimization methodology. In our thesis, after a review of existing path planning methodologies with a focus on energy optimality, we present the background of time-optimal path planning using the level set method. We then lay out the …
-
Bandwidth Selection for Level Set Estimation in the Context of Regression and a Simulation Study for Non Parametric Level Set Estimation When the Density Is Log-Concave
… global loss function becomes suboptimal for the level set estimation problem which is local in nature. For a function $g$, the level set is the set LSλ = {x : g(x) ≥ λ}. In the first part of this thesis we study optimal bandwidth selection for the Nadaraya-Watson kernel estimator in one …
-
A Fire Simulation Model for Heterogeneous Environments Using the Level Set Method
… a scheme we have developed that utilizes a level set method to build a fire spread simulation model. The scheme applies the strengths and overcomes some of the shortcomings of the two major types of simulation method. We store fire data and local rules at cells. Instead of calculating which …
-
People Tracking Under Occlusion Using Gaussian Mixture Model and Fast Level Set Energy Minimization
… are matched to the models using a fast numerical level set method. Since each target is tracked with its blob's information, the system is capable of handling partial or full occlusion during tracking. Experimental results on a number of challenging sequences that were collected in …
-
Multidisciplinary design of thermally radiating structures using a level set based topology optimization approach
… manufacturing techniques. This thesis presents a level set based topology optimization approach for designing thermally efficient radiating structures considering multiple objectives, constraints and disciplines. Level set based methods offer a key advantage of defining crisp structural boundaries …
-
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. …
-
A nonparametric-validated surrogate approach to shape optimization using a level-set based gemoetry description
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Aeronautics and Astronautics, 1998.
-
Regularity of the Level Set Equation for Mean Curvature Flow with an Axis of Symmetry
… the regularity of viscosity solutions to the level set equation for mean curvature flow. We describe a set of hypotheses under which we can prove that the level sets of these solutions are C¹,¹ submanifolds of spacetime with well understood behavior near singular times. We then relate the …
-
Time-optimal path planning in uncertain flow fields using stochastic dynamically orthogonal level set equations
… new stochastic Dynamically Orthogonal (DO) Level Set equations to account for uncertainty in the flow field. We first review existing path-planning work: time-optimal path planning using the level set method, and energy-optimal path planning using stochastic DO level set equations. We build …
-
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 …
-
A study of Taylor bubbles in vertical and inclined slug flow using multiphase CFD with level set
… (ITMs) where the interface is tracked with a Level-Set method implemented in the commercial code TransAT®. In the literature, the Taylor bubble velocity is modeled based on two different contributions: (i) the drift velocity, i.e., the velocity of propagation of a Taylor bubble in stagnant …
-
Chemical vapor deposition modeling using direct simulation Monte Carlo with non-linear chemistry and level set profile evolution
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.
-
Finite-element simulations of interfacial flows with moving contact lines
In this work, we develop an interface-preserving level-set method in the finite-element framework for interfacial flows with moving contact lines. In our method, the contact line is advected naturally by the flow field. Contact angle hysteresis can be easily implemented without explicit calculation …
Page 1 of 9