共查询到20条相似文献,搜索用时 15 毫秒
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The problem of interest is to estimate the concentration curve and the area under the curve (AUC) by estimating the parameters of a linear regression model with autocorrelated error process. We introduce a simple linear nonparametric unbiased estimator of the concentration curve and the AUC. We show that this estimator constructed from an appropriate regular sampling design is asymptotically optimal. 相似文献
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Jocelyne Erhel Zoubida Mghazli Mestapha Oumouni 《Comptes Rendus Mathematique》2011,349(15-16):861-865
In this Note, we present an efficient method to approximate the expectation of the response of a one-dimensional elliptic problem with stochastic inputs. In conventional methods, the computational effort and cost of the approximation of the response can be dramatic. Our method presented here is based on the Karhunen–Loève (K-L) expansion of the inverse of the diffusion parameter, allowing us to build a base of random variables in reduced numbers, from which we construct a projected solution. We show that the expectation of this projected solution is a good approximation, and give an a priori error estimate. A numerical example is presented to show the efficiency of this approach. 相似文献
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Adaptive computation using adaptive meshes is now recognized as essential for solving complex PDE problems. This computation requires, at each step, the definition of a continuous metric field to govern the generation of the adapted meshes. In practice, via an appropriate a posteriori error estimation, metrics are calculated at the vertices of the computational domain mesh. In order to obtain a continuous metric field, the discrete field is interpolated in the whole domain mesh. In this Note, a new method for interpolating discrete metric fields, based on a so-called “natural decomposition” of metrics, is introduced. The proposed method is based on known matrix decompositions and is computationally robust and efficient. Some qualitative comparisons with classical methods are made to show the relevance of this methodology. 相似文献
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Samuele Giraudo 《Comptes Rendus Mathematique》2012,350(11-12):549-552
We study a functorial construction from the category of monoids to the category of set-operads and we give some combinatorial examples of applications. 相似文献
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Armand Borel 《Commentarii Mathematici Helvetici》1955,29(1):27-39
Sans résumé
A Monsieur H. Hopf, à l’occasion de son soixantième anniversaire 相似文献
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Anatole Khelif 《Comptes Rendus Mathematique》2006,342(6):377-380
In a recent preprint, George M. Bergman has investigated the following property:for any generating set X of the group G there exists an integer n such that any element of G is a product of n elements of . We will say in this case that G has the Bergman property.We have solved some of the questions asked in the above mentioned preprint and have found it suitable to investigate this property in a more general context, in particular for rings (essentially Boolean rings). To cite this article: A. Khelif, C. R. Acad. Sci. Paris, Ser. I 342 (2006). 相似文献
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Zenon Moszner 《Aequationes Mathematicae》1989,37(2-3):267-278
Résumé En généralisant un résultat de J. Aczél et M. Hosszú on donne des conditions nécessaires et suffisantes pour qu'une solution de l'équation de translationF(F(, x), y) = F(, xy), oùF: × G , est un ensemble arbitraire,G forme un groupe, soit de la formeF(, x) = f
–1(f()·1(x)), oùf est une bijection de au groupeG
1 isomorphe avecG et 1 est un homomorphisme deG àG
1. On considère aussi le cas oùG forme un espace vectoriel sur le corps des nombres rationels.Si est un intervalle ayant plus qu'un point etG = R
m
avec l'addition comme l'opération on trouve des conditions pour que la fonction continueF soit de la formeF(, x
1,, x
m
) =f
–1(f() + c
1
x
1 + +c
m
x
m
), oùf est une homéomorphie de àR et (c
1,,c
m
) R
m
.
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