Documents disponibles écrits par cet auteur

Estimation of extremes: conventional versus Bayesian techniques / Panagiota Galiatsatou in Journal of hydraulic research, Vol. 46 extra issue (Mars/Avril 2008) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 211-223 Titre : Estimation of extremes: conventional versus Bayesian techniques Titre original : Estimation des extrêmes: techniques conventionnelles contre Bayesiènnes Type de document : texte imprimé Auteurs : Panagiota Galiatsatou, Auteur ; Panagiotis Prinos, Auteur ; Agustin Sanchez-Arcilla, Auteur Article en page(s) : pp. 211-223 Note générale : Hydraulique Résumé en Français Langues : Anglais (eng) Mots-clés : Bayesian  technique  Log-transformed  surge  data  ML  estimators  Near  flat  distribution  Neighborhood  information  Parameter  uncertainty Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The Bayesian and Maximum Likelihood (ML) estimators of surges at two stations of the Dutch coast on the North Sea are compared herein. The ML approach is commonly used, while the Bayesian approach allows both for a parameter uncertainty and a randomness inclusion in future observations. In the Bayesian framework, two different ways of constructing prior distributions are examined, namely the near flat distributions for model parameters and the incorporation of information from neighborhood sites of that under consideration through the distribution of quantile differences. The Bayesian framework offers substantial advantages to analyze the extreme values in both cases. The analysis is also performed using log-transformed surge data. This selection is proven to be advantageous for naturally bounded variables and to better capture the “relative” character of extremes. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com [article] Estimation of extremes: conventional versus Bayesian techniques = Estimation des extrêmes: techniques conventionnelles contre Bayesiènnes [texte imprimé] / Panagiota Galiatsatou, Auteur ; Panagiotis Prinos, Auteur ; Agustin Sanchez-Arcilla, Auteur . - pp. 211-223. Hydraulique Résumé en Français Langues : Anglais (eng) in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 211-223 Mots-clés : Bayesian  technique  Log-transformed  surge  data  ML  estimators  Near  flat  distribution  Neighborhood  information  Parameter  uncertainty Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The Bayesian and Maximum Likelihood (ML) estimators of surges at two stations of the Dutch coast on the North Sea are compared herein. The ML approach is commonly used, while the Bayesian approach allows both for a parameter uncertainty and a randomness inclusion in future observations. In the Bayesian framework, two different ways of constructing prior distributions are examined, namely the near flat distributions for model parameters and the incorporation of information from neighborhood sites of that under consideration through the distribution of quantile differences. The Bayesian framework offers substantial advantages to analyze the extreme values in both cases. The analysis is also performed using log-transformed surge data. This selection is proven to be advantageous for naturally bounded variables and to better capture the “relative” character of extremes. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com

Extreme values for coastal, estuarine, and riverine environments / Agustin Sanchez-Arcilla in Journal of hydraulic research, Vol. 46 extra issue (Mars/Avril 2008) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 183-190 Titre : Extreme values for coastal, estuarine, and riverine environments Titre original : Valeurs extrêmes dans les environments côtières, estuariens et fluviales Type de document : texte imprimé Auteurs : Agustin Sanchez-Arcilla, Auteur ; Daniel Gonzalez-Marco, Auteur ; Neelke Doorn, Auteur Article en page(s) : pp. 183-190 Note générale : Hydraulique Résumé en Français Langues : Anglais (eng) Mots-clés : Coastal  engineering  Data  analysis  Estuary  Extremes  Probability  Riverine  Statistics Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The increasing pressures associated to the development of coastal zones and near river courses have enhanced the sensitivity of these areas to natural processes such as flooding or erosion. The characterization of the associated drivers and responses, particularly under extreme conditions, has become an acute need for managing those areas and the risks for uses and resources there located. This paper summarizes the work done within Task 2 of the EU Integrated Research Project FLOODsite in the extreme distribution functions related to flood and erosion hazards. A wide range of models, parameters and fitting techniques were applied to a variety of geographic and climatic environments. The emphasis focused on selecting models and techniques based on a parsimony principle, to propose robust extrapolations of characteristic variables for a reliable flood hazard assessment. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com [article] Extreme values for coastal, estuarine, and riverine environments = Valeurs extrêmes dans les environments côtières, estuariens et fluviales [texte imprimé] / Agustin Sanchez-Arcilla, Auteur ; Daniel Gonzalez-Marco, Auteur ; Neelke Doorn, Auteur . - pp. 183-190. Hydraulique Résumé en Français Langues : Anglais (eng) in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 183-190 Mots-clés : Coastal  engineering  Data  analysis  Estuary  Extremes  Probability  Riverine  Statistics Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : The increasing pressures associated to the development of coastal zones and near river courses have enhanced the sensitivity of these areas to natural processes such as flooding or erosion. The characterization of the associated drivers and responses, particularly under extreme conditions, has become an acute need for managing those areas and the risks for uses and resources there located. This paper summarizes the work done within Task 2 of the EU Integrated Research Project FLOODsite in the extreme distribution functions related to flood and erosion hazards. A wide range of models, parameters and fitting techniques were applied to a variety of geographic and climatic environments. The emphasis focused on selecting models and techniques based on a parsimony principle, to propose robust extrapolations of characteristic variables for a reliable flood hazard assessment. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com

Extremes for scarce data: the role of Bayesian and scaling techniques in reducing uncertainty / Agustin Sanchez-Arcilla in Journal of hydraulic research, Vol. 46 extra issue (Mars/Avril 2008) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 224-234 Titre : Extremes for scarce data: the role of Bayesian and scaling techniques in reducing uncertainty Titre original : Extremes à partir des samples limitées: techniques Bayesiennes et de changement d'échelles pour reduire les incertitudes Type de document : texte imprimé Auteurs : Agustin Sanchez-Arcilla, Auteur ; Jesus Gomez Aguar, Auteur ; Juan Jose Egozcue, Auteur Article en page(s) : pp. 224-234 Note générale : Hydraulique Résumé en Français Langues : Anglais (eng) Mots-clés : Extremes  Scaling  Selection  Threshold  Wave Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This paper deals with the analysis of extreme wave heights and their uncertainties. The main purpose is to assess confidence intervals using a conventional extreme value, and a Bayesian approach. It is shown how the introduction of an a priori information helps to bound the upper confidence limit. The analysis is performed with wave-height data recorded off the Spanish Catalan coast (NW Mediterranean) and wave-height data from the Dutch coast (North Sea). An analysis with natural-scale and log-transformed wave-height time series has been performed. This scale selection is proven to be advantageous for naturally bounded variables and also better captures some distribution features. The paper ends with a discussion on how the different techniques can be used to select a statistically robust threshold for an extreme event definition. This affects the evaluation of risk in low-lying coastal areas, associated to variables controlling flooding and erosion risks. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com [article] Extremes for scarce data: the role of Bayesian and scaling techniques in reducing uncertainty = Extremes à partir des samples limitées: techniques Bayesiennes et de changement d'échelles pour reduire les incertitudes [texte imprimé] / Agustin Sanchez-Arcilla, Auteur ; Jesus Gomez Aguar, Auteur ; Juan Jose Egozcue, Auteur . - pp. 224-234. Hydraulique Résumé en Français Langues : Anglais (eng) in Journal of hydraulic research > Vol. 46 extra issue (Mars/Avril 2008) . - pp. 224-234 Mots-clés : Extremes  Scaling  Selection  Threshold  Wave Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This paper deals with the analysis of extreme wave heights and their uncertainties. The main purpose is to assess confidence intervals using a conventional extreme value, and a Bayesian approach. It is shown how the introduction of an a priori information helps to bound the upper confidence limit. The analysis is performed with wave-height data recorded off the Spanish Catalan coast (NW Mediterranean) and wave-height data from the Dutch coast (North Sea). An analysis with natural-scale and log-transformed wave-height time series has been performed. This scale selection is proven to be advantageous for naturally bounded variables and also better captures some distribution features. The paper ends with a discussion on how the different techniques can be used to select a statistically robust threshold for an extreme event definition. This affects the evaluation of risk in low-lying coastal areas, associated to variables controlling flooding and erosion risks. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.journalhydraulicresearch.com

Large-scale experiments on dune erosion processes / Giuseppe Roberto Tomasicchio in Journal of hydraulic research, Vol. 49 Supplément 1 (2011) 

Public ISBD [article]  in Journal of hydraulic research > Vol. 49 Supplément 1 (2011) . - pp. 20-30 Titre : Large-scale experiments on dune erosion processes Type de document : texte imprimé Auteurs : Giuseppe Roberto Tomasicchio, Auteur ; Agustin Sanchez-Arcilla, Auteur ; Felice D'Alessandro, Auteur Année de publication : 2012 Article en page(s) : pp. 20-30 Note générale : Hydraulique Langues : Anglais (eng) Mots-clés : Breaching  Dune  erosion  Large-scale  experiment  Numerical  model  Overwash Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This research provides an overview of the large-scale physical model experiments conducted at the Canal d'Investigaciò i Esperimentaciò Mar‘ıtima, Laboratori d'Enginyeria Mar‘ıtima, Universitat Politècnica de Catalunya, Barcelona, within the EU-Hydralab III Integrated Infrastructure Initiative. The model tests have been carried out in a flume with a sandy dune exposed to a combination of water levels and wave conditions. Different regimes of wave attacks on the sandy beach/dune system were investigated. In particular, the study provides a unique set of large-scale physical data concerning the wave-induced dune overwash. Measurements of velocities, sediment concentrations and beach–dune profile evolutions were considered. The profile measurements have been used to calibrate and validate a numerical model predicting the beach–dune profile modifications over the near-shore region. The numerical model compares well with the experimental data. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.604574 [article] Large-scale experiments on dune erosion processes [texte imprimé] / Giuseppe Roberto Tomasicchio, Auteur ; Agustin Sanchez-Arcilla, Auteur ; Felice D'Alessandro, Auteur . - 2012 . - pp. 20-30. Hydraulique Langues : Anglais (eng) in Journal of hydraulic research > Vol. 49 Supplément 1 (2011) . - pp. 20-30 Mots-clés : Breaching  Dune  erosion  Large-scale  experiment  Numerical  model  Overwash Index. décimale : 627 Ingénierie des cours d'eau naturels, des ports, des rades et des cotes. Installations de navigation, de dragage, de récupération et de sauvetage. Barrages et centrales électriques hydrauliques Résumé : This research provides an overview of the large-scale physical model experiments conducted at the Canal d'Investigaciò i Esperimentaciò Mar‘ıtima, Laboratori d'Enginyeria Mar‘ıtima, Universitat Politècnica de Catalunya, Barcelona, within the EU-Hydralab III Integrated Infrastructure Initiative. The model tests have been carried out in a flume with a sandy dune exposed to a combination of water levels and wave conditions. Different regimes of wave attacks on the sandy beach/dune system were investigated. In particular, the study provides a unique set of large-scale physical data concerning the wave-induced dune overwash. Measurements of velocities, sediment concentrations and beach–dune profile evolutions were considered. The profile measurements have been used to calibrate and validate a numerical model predicting the beach–dune profile modifications over the near-shore region. The numerical model compares well with the experimental data. DEWEY : 627 ISSN : 0022-1686 En ligne : http://www.tandfonline.com/doi/abs/10.1080/00221686.2011.604574