Results 1  10
of
37
Minimum energy mobile wireless networks revisited
 In IEEE International Conference on Communications (ICC
, 2001
"... Energy conservation is a critical issue in designing wireless ad hoc networks, as the nodes are powered by batteries only. Given a set of wireless network nodes, the directed weighted transmission graph Gt has an edge uv if and only if node v is in the transmission range of node u and the weight of ..."
Abstract

Cited by 118 (8 self)
 Add to MetaCart
Energy conservation is a critical issue in designing wireless ad hoc networks, as the nodes are powered by batteries only. Given a set of wireless network nodes, the directed weighted transmission graph Gt has an edge uv if and only if node v is in the transmission range of node u and the weight of uv is typically defined as II,,vll + c for a constant 2 <_ t ~ < 5 and c> O. The minimum power topology Gm is the smallest subgraph of Gt that contains the shortest paths between all pairs of nodes, i.e., the union of all shortest paths. In this paper, we described a distributed positionbased networking protocol to construct an enclosure graph G~, which is an approximation of Gin. The time complexity of each node u is O(min(dG ~ (u)dG ~ (u), dG ~ (u) log dG ~ (u))), where dc(u) is the degree of node u in a graph G. The space required at each node to compute the minimum power topology is O(dG ~ (u)). This improves the previous result that computes Gm in O(dG, (u) a) time using O(dGt(U) 2) spaces. We also show that the average degree dG,(u) is usually a constant, which is at most 6. Our result is first developed for stationary network and then extended to mobile networks. I.
Sliver Exudation
 ANNUAL SYMPOSIUM ON COMPUTATIONAL GEOMETRY
, 1999
"... A sliver is a tetrahedron whose four vertices lie close to a plane and whose orthogonal projection to that plane is a convex quadrilateral with no short edge. Slivers are notoriously common in 3dimensional Delaunay triangulations even for wellspaced point sets. We show that if the Delaunay triangu ..."
Abstract

Cited by 81 (11 self)
 Add to MetaCart
A sliver is a tetrahedron whose four vertices lie close to a plane and whose orthogonal projection to that plane is a convex quadrilateral with no short edge. Slivers are notoriously common in 3dimensional Delaunay triangulations even for wellspaced point sets. We show that if the Delaunay triangulation has the ratio property introduced in [15] then there is an assignment of weights so the weighted Delaunay triangulation contains no slivers. We also give an algorithm to compute such a weight assignment.
Quality Meshing with Weighted Delaunay Refinement
 SIAM J. Comput
, 2002
"... Delaunay meshes with bounded circumradius to shortest edge length ratio have been proposed in the past for quality meshing. The only poor quality tetrahedra called slivers that can occur in such a mesh can be eliminated by the sliver exudation method. This method has been shown to work for periodic ..."
Abstract

Cited by 39 (7 self)
 Add to MetaCart
Delaunay meshes with bounded circumradius to shortest edge length ratio have been proposed in the past for quality meshing. The only poor quality tetrahedra called slivers that can occur in such a mesh can be eliminated by the sliver exudation method. This method has been shown to work for periodic point sets, but not with boundaries. Recently a randomized pointplacement strategy has been proposed to remove slivers while conforming to a given boundary. In this paper we present a deterministic algorithm for generating a weighted Delaunay mesh which respects the input boundary and has no poor quality tetrahedron including slivers. This success is achieved by combining the weight pumping method for sliver exudation and the Delaunay refinement method for boundary conformation. We show that an incremental weight pumping can be mixed seamlessly with vertex insertions in our weighted Delaunay refinement paradigm. 1
Sparse Voronoi Refinement
 In Proceedings of the 15th International Meshing Roundtable
, 2006
"... a conformal Delaunay mesh in arbitrary dimension with guaranteed mesh size and quality. Our algorithm runs in outputsensitive time O(nlog(L/s) + m), with constants depending only on dimension and on prescribed element shape quality bounds. For a large class of inputs, including integer coordinates, ..."
Abstract

Cited by 32 (21 self)
 Add to MetaCart
a conformal Delaunay mesh in arbitrary dimension with guaranteed mesh size and quality. Our algorithm runs in outputsensitive time O(nlog(L/s) + m), with constants depending only on dimension and on prescribed element shape quality bounds. For a large class of inputs, including integer coordinates, this matches the optimal time bound of Θ(n log n + m). Our new technique uses interleaving: we maintain a sparse mesh as we mix the recovery of input features with the addition of Steiner vertices for quality improvement. 1
Smoothing and Cleaning up Slivers
, 2000
"... RTSU'VWXZYJVS.[]\XZ\Y/[M^OX_Y`acbd^O`SXfeg`hiYJWX5Y\VjXSkUVXPj5U'`MSXl\`m[ U'[MaOXl[3a%_obd^i`SX n X5Y n XaO_iVjhiU=[pY n Y`pq1Xj5\V`Mar\`P\^%[3\ n U=[3aOXfVS [.j5`a)WX5s]t>h%[_)YVU=[p\X5Y/[MUbdV\^uai`.S^O`3Y\vX_iwXMxzyUVWX5YS@[3YXk{G`M\^ hia%_XSVY/[M{OUXl[MaO_hO{iV=t>hiV\`MhOSCVar}3~_V'fX5aOSV`aO ..."
Abstract

Cited by 31 (15 self)
 Add to MetaCart
RTSU'VWXZYJVS.[]\XZ\Y/[M^OX_Y`acbd^O`SXfeg`hiYJWX5Y\VjXSkUVXPj5U'`MSXl\`m[ U'[MaOXl[3a%_obd^i`SX n X5Y n XaO_iVjhiU=[pY n Y`pq1Xj5\V`Mar\`P\^%[3\ n U=[3aOXfVS [.j5`a)WX5s]t>h%[_)YVU=[p\X5Y/[MUbdV\^uai`.S^O`3Y\vX_iwXMxzyUVWX5YS@[3YXk{G`M\^ hia%_XSVY/[M{OUXl[MaO_hO{iV=t>hiV\`MhOSCVar}3~_V'fX5aOSV`aO[MUvXU'[MhOaO[c\YV~ [3aOwMhOU'[3\V`aiSx*WXalbd^OXal\^OX n `MVa)\~ SX5\dVSb*X5U'U~ S n [3jX9_A%SUVWX5YS [fYXShiU\9xF*^OVS [ n XZYdS^O`9bdS*\^%[p\dShOj/^][ n `MVa)\*SX5\ n X5YfV\S [$S[3UU n X5Y\hY{%[3\V`MaJbd^O`MSXzvXU'[MhOaO[\YV'[MaiwhiU=[p\V`afj`Ma)\/[3VaOS ai`PSUVWX5YSxk \C[3U'S`PwVWXS$_iX5\X5YfVaiV'S1\Vj[MUw`3YV\^OfSv\^O[3\Cj`M.~ hi\X\^OX n X5Y\hiY{O[3\V`ar`3ev n `MVa)\SJV'a\VfXPJ$U`wkbdV\^ `MaOX n Y`>jXSS`MYv[MaO_]VaP\VfXkJU`w*bdV\^mJ n Y`>jXSS`MYSx Mi@G9 ,.6J9579O)79BC8M1579>G979BC +3>6 1BC6Z;>+u9579Z p/BC6mBC7376 BC6/8i 1.
Dense Point Sets Have Sparse Delaunay Triangulations
"... Delaunay triangulations and Voronoi diagrams are one of the most thoroughly studies objects in computational geometry, with numerous applications including nearestneighbor searching, clustering, finiteelement mesh generation, deformable surface modeling, and surface reconstruction. Many algorithms ..."
Abstract

Cited by 30 (2 self)
 Add to MetaCart
Delaunay triangulations and Voronoi diagrams are one of the most thoroughly studies objects in computational geometry, with numerous applications including nearestneighbor searching, clustering, finiteelement mesh generation, deformable surface modeling, and surface reconstruction. Many algorithms in these application domains begin by constructing the Delaunay triangulation or Voronoi diagram of a set of points in R³. Since threedimensional Delaunay triangulations can have complexity Ω(n²) in the worst case, these algorithms have worstcase running time \Omega (n2). However, this behavior is almost never observed in practice except for highlycontrived inputs. For all practical purposes, threedimensional Delaunay triangulations appear to have linear complexity. This frustrating
Generating WellShaped Delaunay Meshes in 3D
, 2001
"... A triangular mesh in 3D is a decomposition of a given geometric domain into tetrahedra. The mesh is wellshaped if the aspect ratio of every of its tetrahedra is bounded from aboveby a constant. It is Delaunayifthe interior of the circumsphere of each of its tetrahedra does not contain any other mes ..."
Abstract

Cited by 28 (0 self)
 Add to MetaCart
A triangular mesh in 3D is a decomposition of a given geometric domain into tetrahedra. The mesh is wellshaped if the aspect ratio of every of its tetrahedra is bounded from aboveby a constant. It is Delaunayifthe interior of the circumsphere of each of its tetrahedra does not contain any other mesh vertices. Generating a wellshaped Delaunay mesh for any 3D domain has been a long term outstanding problem. In this paper, wepresent an efficient 3D Delaunay meshing algorithm that mathematically guarantees the wellshape quality of the mesh, if the domain does not have acute angles. The main ingredient of our algorithm is a novel refinement technique which systematically forbids the formation of slivers, a family of bad elements that none of the previous known algorithms can cleanly remove, especially near the domain boundary  needless to say, that our algorithm ensure that there is no sliver near the boundary of the domain.
Delaunay refinement for piecewise smooth complexes
 Proc. 18th Annu. ACMSIAM Sympos. Discrete Algorithms
, 2007
"... We present a Delaunay refinement algorithm for meshing a piecewise smooth complex in three dimensions. The algorithm protects edges with weighted points to avoid the difficulty posed by small angles between adjacent input elements. These weights are chosen to mimic the local feature size and to sati ..."
Abstract

Cited by 23 (5 self)
 Add to MetaCart
We present a Delaunay refinement algorithm for meshing a piecewise smooth complex in three dimensions. The algorithm protects edges with weighted points to avoid the difficulty posed by small angles between adjacent input elements. These weights are chosen to mimic the local feature size and to satisfy a Lipschitzlike property. A Delaunay refinement algorithm using the weighted Voronoi diagram is shown to terminate with the recovery of the topology of the input. Guaranteed bounds on the aspect ratios, normal variation and dihedral angles are also provided. To this end, we present new concepts and results including a new definition of local feature size and a proof for a generalized topological ball property. 1
Biting: Advancing Front Meets Sphere Packing
 INT. JOUR. FOR NUMERICAL METHODS IN ENG
, 1999
"... A key step in the finite element method is to generate a high quality mesh that is as small as possible for an input domain. Several meshing methods and heuristics have been developed and implemented. Methods based on advancing front, Delaunay triangulations, and quadtrees/octrees are among the most ..."
Abstract

Cited by 20 (9 self)
 Add to MetaCart
A key step in the finite element method is to generate a high quality mesh that is as small as possible for an input domain. Several meshing methods and heuristics have been developed and implemented. Methods based on advancing front, Delaunay triangulations, and quadtrees/octrees are among the most popular ones. Advancing front uses simple data structures and is efficient. Unfortunately, in general, it does not provide any guarantee on the size and quality of the mesh it produces. On the other hand, the circlepacking based Delaunay methods generate a wellshaped mesh whose size is within a constant factor of the optimal. In this paper, we present a new meshing algorithm, the biting method, which combines the strengths of advancing front and circle packing. We prove that it generates a high quality 2D mesh, and the size of the mesh is within a constant factor of the optimal.
ThreeDimensional Delaunay Mesh Generation
 Discrete and Computational Geometry
, 2004
"... We propose an algorithm to compute a conforming Delaunay mesh of a bounded domain specified by a piecewise linear complex. Arbitrarily small input angles are allowed, and the input complex is not required to be a manifold. ..."
Abstract

Cited by 16 (6 self)
 Add to MetaCart
We propose an algorithm to compute a conforming Delaunay mesh of a bounded domain specified by a piecewise linear complex. Arbitrarily small input angles are allowed, and the input complex is not required to be a manifold.