721 research outputs found
Fast Color Space Transformations Using Minimax Approximations
Color space transformations are frequently used in image processing,
graphics, and visualization applications. In many cases, these transformations
are complex nonlinear functions, which prohibits their use in time-critical
applications. In this paper, we present a new approach called Minimax
Approximations for Color-space Transformations (MACT).We demonstrate MACT on
three commonly used color space transformations. Extensive experiments on a
large and diverse image set and comparisons with well-known multidimensional
lookup table interpolation methods show that MACT achieves an excellent balance
among four criteria: ease of implementation, memory usage, accuracy, and
computational speed
Competition between species can drive public-goods cooperation within a species
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2012.Cataloged from PDF version of thesis.Includes bibliographical references (p. 40-43).Costly cooperative strategies are vulnerable to exploitation by cheats. Microbial studies have suggested that cooperation can be maintained in nature by mechanisms such as reciprocity, spatial structure and multi-level selection. So far, however, almost all laboratory experiments aimed at understanding cooperation have relied on studying a single species in isolation. In contrast, species in the wild live within complex communities where they interact with other species. Little effort has focused on understanding the effect of interspecies competition on the evolution of cooperation within a species. We test this relationship by using sucrose metabolism of budding yeast as a model cooperative system. We find that when co-cultured with a bacterial competitor, yeast populations become more cooperative compared to isolated populations. We show that this increase in cooperation within yeast is mainly driven by resource competition imposed by the bacterial competitor. A similar increase in cooperation is observed iby Hasan Celiker.S.M
On Euclidean Norm Approximations
Euclidean norm calculations arise frequently in scientific and engineering
applications. Several approximations for this norm with differing complexity
and accuracy have been proposed in the literature. Earlier approaches were
based on minimizing the maximum error. Recently, Seol and Cheun proposed an
approximation based on minimizing the average error. In this paper, we first
examine these approximations in detail, show that they fit into a single
mathematical formulation, and compare their average and maximum errors. We then
show that the maximum errors given by Seol and Cheun are significantly
optimistic.Comment: 9 pages, 1 figure, Pattern Recognitio
Error Analysis of an HDG Method for a Distributed Optimal
In this paper, we present a priori error analysis of a hybridizable discontinuous Galerkin (HDG) method for a distributed optimal control problem governed by diffusion equations. The error estimates are established based on the projection-based approach recently used to analyze these methods for the diffusion equation. We proved that for approximations of degree k on conforming meshes, the orders of convergence of the approximation to fluxes and scalar variables are k+1 when the local stabilization parameter is suitably chosen
An Efficient Finite Element Method with Exponential Mesh Refinement for the Solution of the Allen-Cahn Equation in Non-Convex Polygons
Comment on Ligature of the Left Main Coronary Artery after Surgery in Kawasaki Disease: Case Report
A Highly-Accurate Finite Element Method with Exponentially Compressed Meshes for the Solution of the Dirichlet Problem of the generalized Helmholtz Equation with Corner Singularities
Do Mutual Funds Herd in Industries?
This study examines whether mutual funds herd in industries and the extent to which such herding impacts industry valuations. Using two herding measures proposed by Lakonishok et al. (1992) and Sias (2004) we document that mutual funds herd in industries. We show that industry herding is not driven by fund flows and that it is not a manifestation of individual stock herding. We also find evidence indicating that herding in industries by mutual funds is related to the industry momentum phenomenon first documented by Moskowitz and Grinblatt (1999), but it does not drive industry valuations away from their fundamentals
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