Results 271 to 280 of about 50,256 (293)

Analytical derivation of the point spread function for pinhole collimators

Physics in Medicine and Biology, 2006
The point spread function (PSF) of a pinhole collimator plays an important role in determining the resolution and characterizing the sensitivity of the accepted photons from a given point in the image space. The focus of this paper is to derive an analytical expression for the PSF of two different types of focusing pinhole collimators that are based on
Girish, Bal, Paul D, Acton
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Analytic Models for the Patchy Spread of Plant Disease

Bulletin of Mathematical Biology, 1999
Plant epidemiologists have long been concerned with the patchy nature of plant disease epidemics. This paper presents a new analytical model for patchy plant epidemics (and patchy dynamics in general), using a second-order approximation to capture the spatial dynamics in terms of the densities and spatial covariances of healthy and infected hosts ...
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Note on analytic spread and asymptotic sequences

Mathematical Proceedings of the Cambridge Philosophical Society, 1983
Since the foundational paper (10) by Northcott and Rees in 1954 there have been quite a few papers concerning reductions of ideals and the analytic spread of an ideal. One particular line of investigation concerning the analytic spread l(I) of an ideal I in a local ring (R, M) was begun in 1972 by Burch in (5), where it was shown that l(I) ≤ altitude R
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ANALYTIC SPREAD AND SCHEME-THEORETIC GENERATION

Communications in Algebra, 2001
Let I be a homogeneous ideal in a positively graded affine k-algebra (where k is an infinite field). We characterize the scheme-theoretic generations J of I which are reductions of I; we deduce that l(I) ≤ σ(I) where l(I) is the analytic spread of I and σ(I) denotes the minimal number of the scheme-theoretic generations of I.
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Rings associated with ideals and analytic spread

Mathematical Proceedings of the Cambridge Philosophical Society, 1981
Let A be a Noether ring and let = (a1,…, ar) be an ideal of A. There are a number of graded rings that we can associate with . In this paper we shall be concerned with the following.
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Analytic evaluation of the intensity point spread function

Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena, 2000
The intensity point spread function (PSF) for geometric imaging such as occurs in a projection electron system like SCALPEL is derived analytically from the ray aberration coefficients. The results show that, as expected, the PSF for ordinary aberrations has a finite radius and is not Gaussian.
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Visual analytics on the spread of pathogens

Proceedings of the 7th ACM International Conference on Bioinformatics, Computational Biology, and Health Informatics, 2016
Julien Herrmann, Zachary L. Witter, Nakul Patel, Jonathan Kho, Daniel A. Janies, Ümit V. Çatalyürek   +5 more
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Reduction numbers for ideals of higher analytic spread

Mathematical Proceedings of the Cambridge Philosophical Society, 1987
Let (R, M) be a commutative Noetherian local ring having an identity, and assume the residue field R/M is infinite. If I is an ideal in R, recall that an ideal J contained in I is called a reduction of I if JIn = In + 1 for some non-negative integer n.
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Analytical models for fire spread due to radiation

Combustion and Flame, 1989
Abstract Some basic fire bahavior phenomena are described in terms of analytical solutions to simple physical models for the heating of unburned fuel to ignition temperature by radiation from the combustion region. The most interesting result is a model for the intrinsic acceleration experienced by a point fire during its early growth stage, which ...
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Information Spreading in Dynamic Networks: An Analytical Approach

2010
Sensor networks are one of the most relevant concrete examples of dynamic networks. Their dynamic behavior is mainly due to the presence of node/link faults and node mobility. The aim of this chapter is to survey a new approach to study such dynamic networks, recently introduced in [15–19]. The major novelty of this approach relies on two basic issues.
Andrea Clementi, PASQUALE, FRANCESCO
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