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Search Publications by: Javier Bernal (Fed)

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Displaying 26 - 47 of 47

LINDENS: A program for lineament length and density analysis

November 1, 2000
Author(s)
Antonio M. Casas, Angel Cortes, Adolfo Maestro, M. Asuncion Soriano, Andres Riaguas, Javier Bernal
Analysis of lineaments from satellite images normally includes the determination of their orientation and density. The spatial variation in the orientation and/or number of lineaments must be obtained by means of a network of cells, the lineaments included

Field Demonstration of Laser Scanning for Excavation Measurement

October 1, 2000
Author(s)
Geraldine S. Cheok, Robert R. Lipman, Christoph J. Witzgall, Javier Bernal, William C. Stone
The use of a scanning laser to measure terrain changes due to excavation at a construction site is described. The objective at this phase of the project is to develop the tools necessary to measure terrain changes in real-time. This paper focuses on

Triangulation-Based L 1 -fitting of Terrain Surfaces

June 1, 1999
Author(s)
Javier Bernal, Christoph J. Witzgall
Given a planar triangulation, the goal is to select elevations at its vertices so that resulting piecewise-linear triangulated surface approximates specified elevations using the L 1-norm as the primary measure-of-fit. Several suboptimal algorithms

Probabilistic computation of Poiseuille flow velocity fields

May 1, 1995
Author(s)
Fern Y. Hunt, J. F. Douglas, Javier Bernal
Velocity fields for Poiseuille flow through tubes having general cross section are calculated using a path integral method involving the first‐passage times of random walks in the interior of the cross sectional domain D of the pipe. This method is applied

Inserting line segments into triangulations and tetrahedralizations

March 1, 1995
Author(s)
Javier Bernal
In this paper, we further develop an algorithm by Bernal, De Floriani, and Puppo, for inserting a line segment into a Constrained Delaunay triangulation. The new version of the algorithm inserts the line segment in exactly the same manner in which the old

Bibliographic notes on voronoi diagrams

April 1, 1993
Author(s)
Javier Bernal
This paper presents a comprehensive annotated bibliography on various theoretical and algorithmic aspects of Voronoi diagrams and related diagrams. Bibliographic notes on the relationship between Voronoi diagrams and solutions to the Euclidean traveling

Computing Delaunay triangulations for comet-shaped polygons

November 1, 1991
Author(s)
Javier Bernal
In this paper, we present two triangulation algorithms which combined produce an algorithm for computing Delaunay triangulations for comet-shaped polygons. The first algorithm constructs in linear time a triangulation for a comet-shaped polygon. The second

An expected linear 3-dimensional Voronoi diagram algorithm

June 1, 1990
Author(s)
Javier Bernal
Let 5 be a set of n sites chosen independently from a uniform distribution in a cube in 3 — dimensional Euclidean space. In this paper, an expected 0{n) algorithm for constructing the Voronoi diagram for 5 together with numerical results obtained from an

On the expected complexity of the 3-dimensional Voronoi diagram

May 1, 1990
Author(s)
Javier Bernal
Let 5 be a set of n sites chosen independently from a uniform distribution in a cube in 3—dimensional Euclidean space. In this paper, work by Bentley, Weide and Yao is extended to show that the Voronoi diagram for 5 has an expected 0{n) number of faces. A

Contour-to-Grid Interpolation with Nonlinear Finite Elements: A Feasibility Study

September 1, 1987
Author(s)
Betty Mandel, Javier Bernal, Christoph J. Witzgall
The U.S. Army Engineer Topographic Laboratories and the National Bureau of Standards investigated the computational feasibility of developing a contour-to-grid algorithm by: (l) sampling a large set of digitized cartographic contour data with a tolerance

Non-Linear Contour-to-Grid Digital Interpolation

October 10, 1986
Author(s)
Betty Mandel, Christoph J. Witzgall, Javier Bernal
A technical approach to the task of performing a contour to grid conversion using nonlinear interpolation has been studied. The approach consists of reconstructing a terrain surface from the digitized contour lines on a map. The approximating surface is