4,498 research outputs found
Limits of Voronoi Diagrams
In this thesis we study sets of points in the plane and their Voronoi
diagrams, in particular when the points coincide. We bring together two ways of
studying point sets that have received a lot of attention in recent years:
Voronoi diagrams and compactifications of configuration spaces. We study moving
and colliding points and this enables us to introduce `limit Voronoi diagrams'.
We define several compactifications by considering geometric properties of
pairs and triples of points. In this way we are able to define a smooth, real
version of the Fulton-MacPherson compactification. We show how to define
Voronoi diagrams on elements of these compactifications and describe the
connection with the limit Voronoi diagrams.Comment: PhD thesis, 132 pages, lots of figure
A Voronoi poset
Given a set S of n points in general position, we consider all k-th order
Voronoi diagrams on S, for k=1,...,n, simultaneously. We deduce symmetry
relations for the number of faces, number of vertices and number of circles of
certain orders. These symmetry relations are independent of the position of the
sites in S. As a consequence we show that the reduced Euler characteristic of
the poset of faces equals zero whenever n odd.Comment: 14 pages 4 figure
Farthest-Polygon Voronoi Diagrams
Given a family of k disjoint connected polygonal sites in general position
and of total complexity n, we consider the farthest-site Voronoi diagram of
these sites, where the distance to a site is the distance to a closest point on
it. We show that the complexity of this diagram is O(n), and give an O(n log^3
n) time algorithm to compute it. We also prove a number of structural
properties of this diagram. In particular, a Voronoi region may consist of k-1
connected components, but if one component is bounded, then it is equal to the
entire region
Kinetic and Dynamic Delaunay tetrahedralizations in three dimensions
We describe the implementation of algorithms to construct and maintain
three-dimensional dynamic Delaunay triangulations with kinetic vertices using a
three-simplex data structure. The code is capable of constructing the geometric
dual, the Voronoi or Dirichlet tessellation. Initially, a given list of points
is triangulated. Time evolution of the triangulation is not only governed by
kinetic vertices but also by a changing number of vertices. We use
three-dimensional simplex flip algorithms, a stochastic visibility walk
algorithm for point location and in addition, we propose a new simple method of
deleting vertices from an existing three-dimensional Delaunay triangulation
while maintaining the Delaunay property. The dual Dirichlet tessellation can be
used to solve differential equations on an irregular grid, to define partitions
in cell tissue simulations, for collision detection etc.Comment: 29 pg (preprint), 12 figures, 1 table Title changed (mainly
nomenclature), referee suggestions included, typos corrected, bibliography
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