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 97 for “"Vector field"”.
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Vector Field Manipulations in Three-Dimensional Time-Varying Flow Data Compression and Image/video Editing
… with image features. A dense correspondence field between source and target images generated by the control curves then guides texture synthesis.
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Dynamic line integral convolution for visualizing electromagnetic phenomena
Vector field visualization is a useful tool in science and engineering, giving us a powerful way of understanding the structure and evolution of the field. A fairly recent technique called Line Integral Convolution (LIC) has improved the level of detail that can be visualized by convolving a random …
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Gaussian processes at the Helm(holtz): A more fluid model for ocean currents
… and identifying divergences in a current vector field based on sparse observations of buoy velocities. Since we expect current velocity to be a continuous but highly non-linear function of spatial location, Gaussian processes (GPs) offer an attractive model. But we show that applying a GP …
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Time-optimal CNC tool paths : a mathematical model of machining
… optimization problem. We seek for a preferable vector field on a surface to obtain skeletal information on the toolpaths. This framework is more amenable to the techniques of continuum mechanics and differential geometry rather than to path generation and conventional CAD/CAM (Computer Aided …
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Shear-free perfect fluid theorems in general relativity
… the consistency of the Einstein gravitational field equations under the barotropic shear-free perfect fluid condition. Using a Mathematica package xTensor, we were able to prove the following cases: the case where the pressure is constant, the acceleration vector is parallel to the vorticity, …
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Convex optimization methods for model reduction
… is reduced through a projection, and then the vector field of the reduced state is approximated for improved computation efficiency. Neither of the above steps has been thoroughly studied. The second part of this thesis presents a solution to a particular problem in the second step above, …
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Topology Optimization Using Load Path and Homogenization
… be decomposed into solenoidal and irrotational fields using Gurtin or Helmholtz decomposition. The load path is calculated using the solenoidal field. A novel method for topology optimization using load paths and total variation of different objective functions is formulated and implemented. …
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Submanifold Helicity
… a way to measure the coiling of flow lines in a vector field, computed by the formula [see formula in PDF file] . To start our exploration of helicity we begin with the topic of differential forms and their correspondence with vector fields in R 3 . Then we use the correspondence of forms and …
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Geometry of Affine Actions
… This allows us to examine globally the left vector field action of the homogeneous Heisenberg subalgebra Hsl2 on FL2. On each cell of the quotient H -\FL2, we find coordinates for the modified non-linear Schrodinger (mNLS) hierarchy, with Miura, maps to NLS coordinates on the Grassmannian. We …
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A control architecture and human interface for agile, reconfigurable micro aerial vehicle formations
… controlling a single quadrotor in an artificial vector field, to controlling a group of quadrotors in a Virtual Rigid Body (VRB) framework, to balancing the effect between the human control and autonomy for collision avoidance, and to fast on-line distributed collision avoidance with Buffered …
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Vector-Galileon-Tensor theories of gravity
… of the cosmological evolution in a particular vector-tensor theory of gravity with a potential and a Galileon-motivated interaction terms is presented. The evolution of vector field self interactions that are relatively related to Galileon fields throughout the expansion history of the universe …
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Reduced-space Gaussian process regression forecast for nonlinear dynamical systems
… method consists of the reconstruction of the vector field in a reduced-order subspace of interest using Gaussian Process Regression (GPR). GPR simultaneously allows for the reconstruction of the vector field, as well as the estimation of the local uncertainty. The latter is due to i) the local …
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Vector fields during cosmic inflation: stability analysis and phenomenological signatures.
This thesis is based on the study of vector fields during cosmic inflation. Cosmic inflation has proven to be an accurate description of the very early universe, not only because of its success in resolving the classical problems of big bang cosmology, but also for introducing a natural mechanism …
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Existence of smooth shock profiles for hyperbolic systems with relaxation
… of a locally invariant manifold M, where the vector field to this ODE system has a smooth extenstion from a dense subset of M throughout M and the classical center manifold theorem applies. We apply our results to exponentially based moment closure systems.
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Phase transition of a vector operator in AdS-CFT
In this thesis, we studied a vector operator in finite density system through AdS-CFT correspondence. By numerically solving the wave equations of the corresponding vector field in a AdS-RN black hole background geometry, we found poles of the retarded Green's functions in momentum space, which …
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Lagrangian-based Simplification and Feature Estimation for Flow Visualization
Vector fields are commonly used in various engineering and scientific applications for the study of different dynamical systems. Their analysis and visualization is of paramount importance to those applications. There are two different representations of vector field (or flow) data, i.e., the …
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Cooperative Control of Miniature Air Vehicles
… a new method for path following using vector fields was developed. A vector field of desired ground track headings is calculated and commanded ground track headings are calculated such that ground track heading error and lateral following error decay asymptotically even in the presence …
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Finite element method using vector finite elements applied to eddy current problems
Vector fields found in electromagnetics are fundamentally different to vector fields found in other research areas such as structural mechanics. Electromagnetic vector fields possess different physical behaviour patterns and different properties in comparison to the other vector fields and therein …
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1. ΕΠΙΦΑΝΕΙΕΣ ΜΕ ΙΣΟΜΕΤΡΙΚΕΣ ΣΚΙΟΓΡΑΜΜΕΣ 2. ΕΠΙΦΑΝΕΙΕΣ ΜΕ ΙΣΟΜΕΤΡΙΚΕΣ ΓΕΩΔΑΙΣΙΑΚΕΣ
… Z WHICH MAPS THE POINT E OF S2 TO A TANGENT VECTOR ZE OF ΣE AT A FIXED SPECIAL POINT OF ΣΕ IF IT IS NOT A CIRCLE. THERE ARE CERTAIN DIFFICULTIES RELATED TO THE FACT THAT Z IS IN GENERAL A MULTIPLE- VALUED FUNCTION, DEPENDING ONTHE POSSIBLE SYMMETRIES OF ΣΕ. THIS PROBLEM IS HANDLED BY SHOWING …
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Effect of Interstitial Fluid Flow and Radiotherapy on Glioblastoma Invasiveness and Progression
… GBM. 4) Developing a novel pipeline for applying vector field topology to the study of interstitial fluid flow in glioma. Surprisingly, we found that motility metrics in vitro have a negative correlation trend with in vivo invasion. Next, we found that radiation causes a transient increase in …
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