Results 91 to 100 of about 25,546 (258)

On approximating copulas by finite mixtures

open access: yes, 2018
Copulas are now frequently used to approximate or estimate multivariate distributions because of their ability to take into account the multivariate dependence of the variables while controlling the approximation properties of the marginal densities ...
Khaled, Mohamad A., Kohn, Robert
core  

An objective Bayesian method for including parameter uncertainty in ensemble model output statistics

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
Conventional model output statistics and ensemble model output statistics methods for calibrating ensemble forecasts lead to severe underestimation of the probabilities of ensemble extremes (in blue). This is because they ignore statistical parameter uncertainty.
Stephen Jewson   +4 more
wiley   +1 more source

Lower Tail Dependence for Archimedean Copulas: Characterizations and Pitfalls [PDF]

open access: yes
Tail dependence copulas provide a natural perspective from which one can study the dependence in the tail of a multivariate distribution.For Archimedean copulas with continuously differentiable generators, regular variation of the generator near the ...
Charpentier, A., Segers, J.J.J.
core   +1 more source

Discrete copulas and quasi-copulas

open access: yes, 2022
The thesis gives a brief introduction to two dimensional copulas and related functions. Firstly, we present copulas, their usage and according history. Furthermore, in the text we include some examples and visual representations for this purpose. Copulas are cumulative distribution functions defined on the unit square with marginal distributions which ...
openaire   +1 more source

A composite‐loss graph neural network for the multivariate post‐processing of ensemble weather forecasts

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
The dual graph neural network (dualGNN), trained with a composite loss combining the energy score (ES) and variogram score (VS), consistently outperformed models optimized solely for ES or the continuous ranked probability score in the multivariate setting, as well as empirical copula approaches.
Mária Lakatos
wiley   +1 more source

An Econometric Study of Vine Copulas [PDF]

open access: yes
We present a new recursive algorithm to construct vine copulas based on an underlying tree structure. This new structure is interesting to compute multivariate distributions for dependent random variables.
Dominique Guegan, Pierre-André Maugis
core  

COBASE: A new copula‐based shuffling method for ensemble weather forecast postprocessing

open access: yesQuarterly Journal of the Royal Meteorological Society, EarlyView.
We propose COBASE, a novel copula‐based postprocessing methododology that combines the strengths of multivariate parametric correction with non‐parametric rank‐based approaches. We consider two case studies for multi‐site temperature in Austria and multi‐site temperature and dew‐point temperature in the Netherlands.
Maurits Flos   +4 more
wiley   +1 more source

Nonparametric Estimation of Copulas for Time Series [PDF]

open access: yes
We consider a nonparametric method to estimate copulas, i.e. functions linking joint distributions to their univariate margins. We derive the asymptotic properties of kernel estimators of copulas and their derivatives in the context of a multivariate ...
Jean-David FERMANIAN, Olivier SCAILLET
core  

Study of meteorological‐hydrological drought propagation under reservoir regulation using a Copula‐Bayesian network in the Hanjiang River Basin

open access: yesRiver, EarlyView.
Study of meteorological‐hydrological drought propagation under reservoir regulation using a Copula‐Bayesian network in the Hanjiang River Basin. Abstract Reservoir operations play a pivotal role in modifying drought propagation processes, particularly by influencing the transition from meteorological to hydrological drought. This study investigates the
Yanping Qu   +5 more
wiley   +1 more source

Tails of correlation mixtures of elliptical copulas

open access: yes, 2009
Correlation mixtures of elliptical copulas arise when the correlation parameter is driven itself by a latent random process. For such copulas, both penultimate and asymptotic tail dependence are much larger than for ordinary elliptical copulas with the ...
Manner, Hans, Segers, Johan
core  

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