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 87 for “"B-Spline"”.
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Geometric trimming of B-spline surfaces
… parametric space on to the three-dimensional B-spline surface. Since visualization for this kind of procedure is vital a tool kit has been developed, using PHIGS, to model B-spline surfaces along with their approximate trimmed surfaces as well as the approximation error involved.
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B-Spline Boundary Element Method for Ships
The development of a three dimensional B-Spline based method, which is suitable for the steady-state potential flow analysis of free surface piercing bodies in hydrodynamics, is presented. The method requires the B-Spline or Non Uniform Rational B-Spline (NURBS) representation of the body as an …
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Computer integrated manufacture of optimal B-spline cams
Call number: LD2668 .T4 ME 1989 T46
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Computer integrated manufacture of optimal B-spline cams
Call number: LD2668 .T4 ME 1989 T46
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Vectorization of Raster Images Using B-Spline Surfaces
… each segment is approximated with a periodic B-Spline curve. This curve is then used to create a B-Spline surface to approximate the interior of the segment. The algorithm fits each B-Spline to the colors of the image using least-squares approximation. The color and shape of each B-Spline …
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Intersection of B-spline surfaces by elimination method
Parametric surface representations such as the B-spline and Bezier geometries are widely used among the aerospace, automobile, and shipbuilding industries. These surfaces have proven to be very advantageous for defining and combining primitive geometries to form complex models. However, the task of …
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Error Visualization in Comparison of B-Spline Surfaces
Geometric trimming of surfaces results in a new mathematical description of the matching surface. This matching surface is required to closely resemble the remaining portion of the original surface. Typically, the approximation error in such cases is measured with a view to minimize it. The data …
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An Object-oriented design for hierarchical B-spline surfaces
… representation of tensor-product hierarchical spline surfaces, multiple offset method support, and general surface representation. This design uses a spatial data structure, the quadtree, to achieve this goal. The quadtree, itself a hierarchical data structure, is very suitable in this …
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Intersection and filleting of non-uniform B-spline surfaces
… of aircraft models to the non-uniform hi-cubic B-Spline surface representation is addressed. The topics discussed in this thesis include the design and development of an interactive graphics user interface, the design and coding of an intersection method for non-uniform hi-cubic B-Spline surfaces …
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Extracting dimensional geometric parameters from B-spline surface models
… Examples of the conversion of data from B-spline surface models to dimensional geometric parameters using these methods are included. The emphasis of this dissertation is on non-uniform B-spline surfaces. Methods for obtaining geometric parameters from aircraft models described by …
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Reverse parameterization of B-spline surfaces for data transfer
… the algorithms and methods for transferring B-spline surface data from a final design CAD tool to a parameter based conceptual design CAD tool. Both codes store data in different ways, requiring a technique referred to as reverse parameteriation to achieve data transfer. Methods are discussed …
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An optimal approach to geometric trimming of B-spline surfaces
… shown to involve obtaining data points on the B-spline surface that lie within the region specified by the parameter values for the trimming curve and describing a new surface which interpolates this new set of data points. This research looks at optimizing the procedure described above by basing …
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Projection, design, and representation of curves on B-spline surfaces
… projecting and mapping plane curves onto a B-spline surface is presented. The curve is mapped onto the surface using normal projection. All points on the curve are projected onto the surface in the direction of the plane normal. Intersections of projected lines and the surface patches are then …
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Skinning engineering models with non-uniform, hierarchical B-spline surfaces
… model with non-uniform, hierarchical B-spline surfaces. Non-uniform, hierarchical B-splines offer the mechanical designer many advantages: parametrically defined components may be added to a surface while maintaining C² surface continuity; detailed features may be added to a surface …
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Optimal Geometric Trimming of B-spline Surfaces for Aircraft Design
B-spline surfaces have been widely used in aircraft design to represent different types of components in a uniform format. Unlike the visual trimming of B-spline surfaces, which hides unwanted portions in rendering, the geometric trimming approach provides a mathematically clean representation. …
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Filleting of aircraft components using non-uniform B-spline surfaces
… between aircraft components is discussed. B-spline surface generation from conceptual geometry data and the relimiting of e surfaces is also presented.
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Data reduction and knot removal for non-uniform B-spline surfaces
B-Spline curves and surfaces are being used throughout the aircraft industry for geometric modeling. Geometric models having accurate surface representations in the non-uniform B-Spline surface format can contain very large quantities of data. The computing power required by a CAD system for …
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Daubechies and quadratic b-spline wavelets for automated early diagnosis of Alzheimer's disease
… signals: Daubechies 4 wavelets and Quadratic B-spline wavelets. Analysis was performed using these two types of wavelets and the coefficients obtained from this analysis were then used with several algorithms for automated classification. Cross validation was performed with a multilayer …
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Rational Cubic B-Spline Interpolation and Its Applications in Computer Aided Geometric Design
<p>Because of the flexibility that the weights and the control points provide, NURBS have recently become very popular tools for the design of curves and surfaces. If the weights are positive then the NURB will lie in the convex hull of its control points and will not possess singularities. Thus it …
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