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Mathematics & Statistics

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Displaying 776 - 800 of 872

DIVERSE: A Framework for Building Extensible and Reconfigurable Device Independent Virtual Environments

February 17, 2003

Author(s)

John T. Kelso, L E. Arsenault, Steven G. Satterfield, Peter M. Ketcham, R D. Kriz

We present DIVERSE, a highly modular collection of complementary software packages designed to facilitate the creation of device independent virtual environments. DIVERSE is free/open source software; an API (Application Programming Interface) written in C

Algorithms and Codes for the Macdonald Function: Recent Progress and Comparisons

February 1, 2003

Author(s)

B R. Fabijonas, Daniel W. Lozier, J M. Rappoport

The modified Bessel function K iŅχ, also known as the Macdonald function, finds application in the Kontorovich-Lebedev integral transform when χ and Ņ are real and positive. In this paper, a comparison of three codes for computing this function is made

Dealing with Degeneracy in Triangulation

November 1, 2002

Author(s)

Francis Sullivan, Isabel M. Beichl

This is a tutorial article on a quick method for dealing with degeneracy in geometric computations with specific reference to triangulation. The type degeneracy targeted by this article that of four or more points on a circle and five or more points on a

Lattice Matching (LM)-Prevention of Inadvertent Duplicate Publications of Crystal Structures

October 1, 2002

Author(s)

Alan D. Mighell

Lattice-matching techniques have proved to be an extremely effective for the identification of unknown crystalline materials. A commonly employed lattice-matching strategy is based on matching the reduced cell of an unknown against a database of known

Reconstructing Images of Bar Codes for Construction Site Object Recognition

September 1, 2002

Author(s)

David E. Gilsinn, Geraldine S. Cheok, Dianne M. O'Leary

This paper discusses a general approach to reconstructing ground truth intensity images of bar codes that have been distorted by LADARoptics. The first part of this paper describes the experimental data collection of several bar code images along with

Conventional Cells--The Last Step Toward General Acceptance of Standard Conventional Cells for the Reporting of Crystallographic Data

August 1, 2002

Author(s)

Alan D. Mighell

The Absolute Integrating Sphere Method is now used at NIST for the detector-based calibration of total luminous flux of lamps, as well as for the realization of the lumen. This method has many benefits for high-accuracy applications, allowing for

Comparative Statistical Analysis of Test Parts Manufactured in Production Environments

June 1, 2002

Author(s)

David E. Gilsinn, Alice V. Ling

Estimating error uncertainties arising in parts produced on machine tools in production machine shops is not a well understood process. The current study details a process of estimating these error uncertainties. A part with significant features was

Shape-Preserving, Multi-Scale Fitting of Bivariate Data by Cubic L 1 Smoothing Splines

May 10, 2002

Author(s)

David E. Gilsinn, J E. Lavery

Bivariate cubic L1 smoothing splines are introduced. The coefficients of a cubic L1 smoothing spline are calculated by minimizing the weighted sum of the L1 norms ofsecond derivatives of the spline and the l1 norm of the residuals of the data-fitting

Estimating Critical Hopf Bifurcation Parameters for a Second Order DelayDifferential Equation with Application to Machine Tool Chatter

May 1, 2002

Author(s)

David E. Gilsinn

Nonlinear time delay differential equations are well known to have arisen in models in physiology, biology and population dynamics. They have also arisen in models of metal cutting processes. Machine tool chatter, from a process called regenerative chatter

The Role of Rendering in the Competence Project in Measurement Science for Optical Reflection and Scattering

May 1, 2002

Author(s)

H B. Westlund, G W. Meyer, Fern Y. Hunt

Rendering is the process of producing a synthetic image using a computer. The best known application is animation and simulation of scenes for the entertainment industry but recognition of its value as a tool for product design in other areas is increasing

Lattice Symmetry and Identification--The Fundamental Role of Reduced Cells in Materials Characterization

February 1, 2002

Author(s)

Alan D. Mighell

In theory, physical crystals can be represented by idealized mathematical lattices. Under appropriate conditions, these representations can be used for a variety of purposes such as identifying, classifying, and understanding the physical properties of

The Relegation Algorithm

March 3, 2001

Author(s)

A Deprit, E Deprit, Jesuus Palacian

Given a perturbed Hamiltonian system, normalization yields a Lie transformation which converts the main part of the Hamiltonian into an integral of the transformed system. An extension of the normalization method--the relegation algorithm--does the same

Constructing Sibson Elements for a Rectangular Mesh

February 1, 2001

Author(s)

David E. Gilsinn

This paper documents the construction of a finite element, called the Sibson element. The shape function of this element is formed on rectangular grids by C 1 splines defined on a triangulation of each subrectangle by dividing it into four subtriangles