59,194 research outputs found
Convergence of the restricted Nelder-Mead algorithm in two dimensions
The Nelder-Mead algorithm, a longstanding direct search method for
unconstrained optimization published in 1965, is designed to minimize a
scalar-valued function f of n real variables using only function values,
without any derivative information. Each Nelder-Mead iteration is associated
with a nondegenerate simplex defined by n+1 vertices and their function values;
a typical iteration produces a new simplex by replacing the worst vertex by a
new point. Despite the method's widespread use, theoretical results have been
limited: for strictly convex objective functions of one variable with bounded
level sets, the algorithm always converges to the minimizer; for such functions
of two variables, the diameter of the simplex converges to zero, but examples
constructed by McKinnon show that the algorithm may converge to a nonminimizing
point.
This paper considers the restricted Nelder-Mead algorithm, a variant that
does not allow expansion steps. In two dimensions we show that, for any
nondegenerate starting simplex and any twice-continuously differentiable
function with positive definite Hessian and bounded level sets, the algorithm
always converges to the minimizer. The proof is based on treating the method as
a discrete dynamical system, and relies on several techniques that are
non-standard in convergence proofs for unconstrained optimization.Comment: 27 page
Biological effects of prolonged expoure of small animals to unusual gaseous environments semiannual report, 1 sep. 1964 - 28 feb. 1965
Biological effect of prolonged exposure of man and small animals to pure oxygen and helium - oxygen environmen
The impact of water on free-falling bodies
Report discussed measures to cushion impact on body falling into water. Heavy loads are generated by impact and by pressures of water cavity collapsing onto the body
Using visualization for visualization : an ecological interface design approach to inputting data
Visualization is experiencing growing use by a diverse community, with continuing improvements in the availability and usability of systems. In spite of these developments the problem of how first to get the data in has received scant attention: the established approach of pre-defined readers and programming aids has changed little in the last two decades. This paper proposes a novel way of inputting data for scientific visualization that employs rapid interaction and visual feedback in order to understand how the data is stored. The approach draws on ideas from the discipline of ecological interface design to extract and control important parameters describing the data, at the same time harnessing our innate human ability to recognize patterns. Crucially, the emphasis is on file format discovery rather than file format description, so the method can therefore still work when nothing is known initially of how the file was originally written, as is often the case with legacy binary data. © 2013 Elsevier Ltd
Banerjee, Sanjoy. Dominant Classes and the State in Development : Theory and the Case of India. Boulder (Col.), WEstview Press, Coll. « A Westview Replica Edition », 1984, 128 p. Danaher, Kevin. The Political Economy of U.S. Policy toward South Africa. Boulder (Col.), Westview Press, Coll. « Westview Special Studies on Africa », 1985, 243 p.
Reaction of the chick to one atmosphere of oxygen
Experiment to determine chicken reaction to 100 percent oxygen at atmospheric pressur
Embryo development and chick growth in a helium - oxygen atmosphere
Embryo development and chick growth in helium- oxygen atmospher
François-Poncet, Jean, La politique économique de l’Allemagne occidentale, Éditions Sirey, Paris, 1970, 404 p.
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