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Estimación no paramétrica de la función de riesgo: aplicaciones a sismología.

Graciela Estévez Pérez, Alejandro Quintela del Río (2001)

Qüestiió

Se estudia la estimación de tipo no paramétrico de la función de riesgo o razón de fallo de una variable aleatoria real. A partir de una muestra X1, X2, ..., Xn de datos no censurados y no necesariamente independientes, se considera un estimador cociente entre el estimador núcleo de la función de densidad y un estimador núcleo de la función de supervivencia, sobre el que se estudia el problema de selección del parámetro ventana. Por medio de un estudio de simulación se observa la ventaja de utilizar...

Estimate of vegetation efficiency on reducing dust concentration produced by a surface coal mine

Řezníček, Hynek, Beneš, Luděk (2019)

Programs and Algorithms of Numerical Mathematics

A new vegetative barrier can help to reduce dust concentration in a surface coal mine neighbourhood. The project reports about quantification of this effect. An air flow field is computed together with the dust transport driven by it using an in-house CFD solver. The 2D cuts of a real geometry of Bílina coal mine in north Bohemia are used. The vegetation is modelled as horizontally homogeneous porous medium which slows the air flow inside. An influence on turbulence and filtering the dust particles...

Estimates based on scale separation for geophysical flows.

François Jauberteau, Roger Temam (2002)

RACSAM

The objective of this work is to obtain theoretical estimates on the large and small scales for geophysical flows. Firstly, we consider the shallow water problem in the one-dimensional case, then in the two-dimensional case. Finally we consider geophysical flows under the hydrostatic hypothesis and the Boussinesq approximation. Scale separation is based on Fourier series, with N models in each spatial direction, and the choice of a cut-off level N1 < N to define large and small scales. We...

Evolution equations for dunes and drumlins.

Andrew C. Fowler (2002)

RACSAM

Las dunas (del desierto o en los ríos) son montículos de arena formados por la acción erosiva del viento (o del agua) sobre el substrato móvil subyacente. Los drumlins son pequeñas colinas que se forman de manera parecida por la acción erosiva de los casquetes polares en los sedimentos móviles de la base, particularmente durante las eras glaciales. Estas formaciones son causadas por una inestabilidad en el sistema acoplado que relaciona la evolución del lecho con las fuerzas de cizalla ejercidas...

Fast Singular Oscillating Limits and Global Regularity for the 3D Primitive Equations of Geophysics

Anatoli Babin, Alex Mahalov, Basil Nicolaenko (2010)

ESAIM: Mathematical Modelling and Numerical Analysis

Fast singular oscillating limits of the three-dimensional "primitive" equations of geophysical fluid flows are analyzed. We prove existence on infinite time intervals of regular solutions to the 3D "primitive" Navier-Stokes equations for strong stratification (large stratification parameter N). This uniform existence is proven for periodic or stress-free boundary conditions for all domain aspect ratios, including the case of three wave resonances which yield nonlinear " 2 1 2 dimensional" limit equations...

Fault monitoring and fault recovery control for position-moored vessels

Shaoji Fang, Mogens Blanke (2011)

International Journal of Applied Mathematics and Computer Science

This paper addresses fault-tolerant control for position mooring of a shuttle or floating production storage and offloading vessels. A complete framework for fault diagnosis is presented. A loss of a sub-sea mooring line buoyancy element and line breakage are given particular attention, since such failures might cause high-risk abortion of an oil-loading operation. With significant drift forces from waves, non-Gaussian elements dominate forces and the residuals designed for fault diagnosis. Hypothesis...

Finite element approximations of a glaciology problem

Sum S. Chow, Graham F. Carey, Michael L. Anderson (2004)

ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique

In this paper we study a model problem describing the movement of a glacier under Glen’s flow law and investigated by Colinge and Rappaz [Colinge and Rappaz, ESAIM: M2AN 33 (1999) 395–406]. We establish error estimates for finite element approximation using the results of Chow [Chow, SIAM J. Numer. Analysis 29 (1992) 769–780] and Liu and Barrett [Liu and Barrett, SIAM J. Numer. Analysis 33 (1996) 98–106] and give an analysis of the convergence of the successive approximations used in [Colinge and...

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