Feature-based decomposition of trimmed surface.

Wu Yiu-Bun.Thesis submitted in: September 2004.Thesis (M.Phil.)--Chinese University of Hong Kong, 2005.Includes bibliographical references (leaves 122-123).Abstracts in English and Chinese.Chapter Chapter 1. --- Introduction --- p.1Chapter Chapter 2. --- Previous Works --- p.2Chapter 2.1. --- Surface Patch ApproachChapter 2.2. --- Triangular Facet ApproachChapter Chapter 3. --- The Decomposition Algorithm --- p.7Chapter 3.1. --- Input to the AlgorithmChapter 3.2. --- Overview of the AlgorithmChapter 3.2.1. --- Voronoi Diagram DevelopmentChapter 3.2.2. --- Feature Point DeterminationChapter 3.2.3. --- Correspondence EstablishmentChapter 3.2.4. --- Surface ApproximationChapter 3.3. --- Output of the AlgorithmChapter Chapter 4. --- Voronoi Diagram Development --- p.16Chapter 4.1. --- Triangulation of the Parametric SpaceChapter 4.1.1. --- Degree of TriangulationChapter 4.2. --- Locating BisectorsChapter 4.2.1. --- Bisector CentroidsChapter 4.2.2. --- Sub-triangulationChapter 4.3. --- Finalizing BisectorsChapter Chapter 5. --- Feature Point Determination --- p.31Chapter 5.1. --- Definition of Feature PointsChapter 5.1.1. --- Continuous Sharp TurnsChapter 5.1.2. --- Discrete Sharp TurnsChapter 5.2. --- Parametric Coordinates of Feature PointsChapter Chapter 6. --- Vertices Correspondence Attachment --- p.42Chapter 6.1. --- Validity of CorrespondencesChapter 6.2. --- Shape NormalizationChapter 6.2.1. --- Normalization with Relative PositionChapter 6.3. --- Ranking ProcessChapter 6.3.1. --- Forward and Backward AttachmentChapter 6.3.2. --- Singly Linked Bisector VerticesChapter Chapter 7. --- Surface Fitting --- p.58Chapter 7.1. --- Parametric PatchesChapter 7.1.1. --- Definition of Parametric Patch RegionChapter 7.1.2. --- Local Parametric Coordinate SystemChapter 7.2. --- Parametric GridsChapter 7.2.1. --- Sample Points on the Patch BoundaryChapter 7.2.2. --- Grid GenerationChapter 7.3. --- Surface Patches ConstructionChapter 7.3.1. --- Knot VectorsChapter 7.3.2. --- Control VerticesChapter Chapter 8. --- Worked Example --- p.71Chapter 8.1. --- Example 1: Deformed Plane 1Chapter 8.2. --- Example 2: Deformed Plane 2Chapter 8.3. --- Example 3: SphereChapter 8.4. --- Example 4: Hemisphere 1Chapter 8.5. --- Example 5: Hemisphere 2Chapter 8.6. --- Example 6: ShoeChapter 8.7. --- Example 7: Shark Main BodyChapter 8.8. --- Example 8: Mask 1Chapter 8.9. --- Example 9: Mask 2Chapter 8.10. --- Example 10: Toy CarChapter Chapter 9. --- Result and Analysis --- p.101Chapter 9.1. --- Continuity between PatchesChapter 9.2. --- Special Cases --- p.102Chapter 9.2.1. --- Degenerated PatchChapter 9.2.2. --- S-Shaped FeatureChapter 9.3. --- Comparison --- p.105Chapter 9.3.1. --- Example 1: Deformed Plane 1Chapter 9.3.2. --- Example 2: Deformed Plane 2Chapter 9.3.3. --- Example 3: SphereChapter 9.3.4. --- Example 4: Hemisphere 1Chapter 9.3.5. --- Example 5: Hemisphere 2Chapter 9.3.6. --- Example 6: ShoeChapter 9.3.7. --- Example 7: Shark Main BodyChapter 9.3.8. --- Example 8: Mask 1Chapter 9.3.9. --- Example 9: Mask 2Chapter 9.3.10. --- Example 10: Toy CarChapter Chapter 10. --- Conclusion --- p.119References --- p.12

Two Pseudobulges in the "Boxy Bulge" Galaxy NGC 5746

Galaxy formation and growth under the {\Lambda}CDM paradigm is expected to proceed in a hierarchical, bottom-up fashion by which small galaxies grow into large galaxies; this mechanism leaves behind large "classical bulges" kinematically distinct from "pseudobulges" grown by internal, secular processes. We use archival data (Spitzer 3.6 \mum wavelength, Hubble Space Telescope H-band, Two Micron All Sky Survey Ks-band, and Sloan Digital Sky Survey gri-band) to measure composite minor- and major-axis surface brightness profiles of the almost-edgeon spiral galaxy NGC 5746. These light profiles span a large range of radii and surface brightnesses to reveal an inner, high surface brightness stellar component that is distinct from the well-known boxy bulge. It is well fitted by S\'ersic functions with indices n = 0.99 \pm 0.08 and 1.17 \pm 0.24 along the minor and major axes, respectively. Since n < 2, we conclude that this innermost component is a secularly-evolved pseudobulge that is distinct from the boxy pseudobulge. This inner pseduobulge makes up 0.136 \pm 0.019 of the total light of the galaxy. It is therefore considerably less luminous than the boxy structure, which is now understood to be a bar seen nearly end-on. The infrared imagery shows further evidence for secular evolution in the form of a bright inner ring of inner radius 9.1 kpc and width 1.6 kpc. NGC 5746 is therefore a giant, pure-disk SB(r)bc galaxy with no sign of a merger-built bulge. We do not understand how such galaxies form in a {\Lambda}CDM universe.Comment: 23 pages, 7 figures, 2 tables; accepted for publication in Ap

An example of requirements for Advanced Subsonic Civil Transport (ASCT) flight control system using structured techniques

The requirements are presented for an Advanced Subsonic Civil Transport (ASCT) flight control system generated using structured techniques. The requirements definition starts from initially performing a mission analysis to identify the high level control system requirements and functions necessary to satisfy the mission flight. The result of the study is an example set of control system requirements partially represented using a derivative of Yourdon's structured techniques. Also provided is a research focus for studying structured design methodologies and in particular design-for-validation philosophies

Conversion of trimmed NURBS surfaces to Catmull-Clark subdivision surfaces

This paper introduces a novel method to convert trimmed NURBS surfaces to untrimmed subdivision surfaces with Bézier edge conditions. We take a NURBS surface and its trimming curves as input, from this we automatically compute a base mesh, the limit surface of which fits the trimmed NURBS surface to a specified tolerance. We first construct the topology of the base mesh by performing a cross-field based decomposition in parameter space. The number and positions of extraordinary vertices required to represent the trimmed shape can be automatically identified by smoothing a cross field bounded by the parametric trimming curves. After the topology construction, the control point positions in the base mesh are calculated based on the limit stencils of the subdivision scheme and constraints to achieve tangential continuity across the boundary. Our method provides the user with either an editable base mesh or a fine mesh whose limit surface approximates the input within a certain tolerance. By integrating the trimming curve as part of the desired limit surface boundary, our conversion can produce gap-free models. Moreover, since we use tangential continuity across the boundary between adjacent surfaces as constraints, the converted surfaces join with G1 continuity. © 2014 The Authors.EPSRC, Chinese Government (PhD studentship) and Cambridge Trust