Now showing items 1-20 of 24

  • Análisis de datos composicionales: aguas, contaminantes, recursos, sociología... 

    Egozcue Rubí, Juan José; Tolosana Delgado, Raimon; Jarauta Bragulat, Eusebio; Ortego Martínez, María Isabel; Díaz Barrero, José Luis (Universitat Politècnica de Catalunya. Escola Tècnica Superior d'Enginyers de Camins Canals i Ports de Barcelona, 2011-11-15)
    Conference lecture
    Open Access
    Los datos composicionales describen las partes de un todo. Se presentan en forma de vectores proporciones, porcentajes, concentraciones químicas etc. y aparecen en multitud de campos de la ciencia y la ingeniería. A pesar ...
  • Análisis y previsión de fenómenos naturales peligrosos 

    Tolosana Delgado, Raimon; Egozcue Rubí, Juan José; Ortego Martínez, María Isabel; Sánchez-Arcilla Conejo, Agustín (Universitat Politècnica de Catalunya. Escola Tècnica Superior d'Enginyers de Camins Canals i Ports de Barcelona, 2011-11-16)
    Conference lecture
    Open Access
    La toma de decisiones referentes al diseño o en sistemas de alerta requieren el estudio de las acciones externas (frecuentemente meteorológicas), la descripción probabilista del sistema (vulnerabilidad, susceptibilidad) ...
  • An Exploratory Multivariate Statistical Analysis to Assess Urban Diversity 

    Salazar Llano, Lorena; Rosas Casals, Martí; Ortego Martínez, María Isabel (2019-07-11)
    Article
    Open Access
    Understanding diversity in complex urban systems is fundamental in facing current and future sustainability challenges. In this article, we apply an exploratory multivariate statistical analysis (i.e., Principal Component ...
  • Bayesian estimation of the orthogonal decomposition of a contingency table 

    Ortego Martínez, María Isabel; Egozcue Rubí, Juan José (2016)
    Article
    Open Access
    In a multinomial sampling, contingency tables can be parametrized by probabilities of each cell. These probabilities constitute the joint probability function of two or more discrete random variables. These probability ...
  • Bayesian estimation of the orthogonal decomposition of a contingency table 

    Ortego Martínez, María Isabel; Egozcue Rubí, Juan José (2015)
    Conference report
    Open Access
    Contingency tables can be parametrized by probabilities of each cell in a multinomial sampling. These probabilities constitute the joint probability function of the two or more discrete random categorical variables. These ...
  • Bayesian trend analysis for daily rainfall series of Barcelona 

    Ortego Martínez, María Isabel; Gibergans Bàguena, José; Tolosana Delgado, Raimon; Egozcue Rubí, Juan José; Llasat Botija, Maria Carmen (2010-07-15)
    Article
    Open Access
    A Point-Over-Threshold approach using a reparameterization of the Generalized Pareto Distribution (GPD) has been used to assess changes in the daily rainfall Barcelona series (1854–2006). A Bayesian approach, considering ...
  • Changes in the occurrence of extreme wave storms in the Catalan coast: a Bayesian approach 

    Corral López, Jesús; Ortego Martínez, María Isabel (Universitat de Barcelona. Edicions i Publicacions, 2016)
    Conference lecture
    Restricted access - publisher's policy
  • Characterizing the evolution of the container traffic share in the mediterranean sea using hierarchical clustering 

    Grifoll Colls, Manel; Karlis, Thanassis; Ortego Martínez, María Isabel (2018-12)
    Article
    Open Access
    This research investigates the traffic share evolution of the container throughput in the Mediterranean ports from 2000 to 2015 considering hierarchical clustering and concentration indexes. Compositional Data analysis ...
  • Checking model-data weather hazard occurrence fit in the context of climate change 

    Tolosana Delgado, Raimon; Ortego Martínez, María Isabel; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín (2011)
    Conference report
    Open Access
    In climate change impact studies it is common to run a given response model (from ecosystem changes to wavestorm or landslide occurrence) nested into one of the available long-term Global or Regional Circulation Models ...
  • Climate change in a Point-Over-Threshold model: an example on ocean-wave-storm hazard in NE Spain 

    Tolosana Delgado, Raimon; Ortego Martínez, María Isabel; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín (2010-09-27)
    Article
    Open Access
    A reparametrization of the Generalized Pareto Distribution is here proposed. It is suitable to parsimoniously check trend assumptions within a Point-Over-Threshold model of hazardous events. This is based on considerations ...
  • Compositional data for global monitoring: the case of drinking water and sanitation 

    Pérez Foguet, Agustí; Giné Garriga, Ricard; Ortego Martínez, María Isabel (2017-07)
    Article
    Open Access
    Introduction At a global level, access to safe drinking water and sanitation has been monitored by the Joint Monitoring Programme (JMP) of WHO and UNICEF. The methods employed are based on analysis of data from household ...
  • Compositional data techniques for the analysis of the container traffic share in a multi-port region 

    Grifoll Colls, Manel; Ortego Martínez, María Isabel; Egozcue Rubí, Juan José (Springer, 2019-12)
    Article
    Open Access
    The statistical techniques based on compositional data are applied to investigate the evolution of the traffic share of the container throughput in a multi-port system. Compositional vectors are those which contain relative ...
  • Estimación bayesiana de cópulas extremales en procesos de Poisson 

    Ortego Martínez, María Isabel (Universitat Politècnica de Catalunya, 2015-02-04)
    Doctoral thesis
    Open Access
    The estimation of occurrence probabilities of extremal quantities is essential in the study of hazards associated with natural phenomena. The extremal quantities of interest usually correspond to phenomena characterized ...
  • Modified Kolmogorov-Smirnov test of goodness of fit 

    Monti, Gianna S.; Mateu Figueras, Gloria; Ortego Martínez, María Isabel; Pawlowsky Glahn, Vera; Egozcue Rubí, Juan José (2017)
    Conference report
    Open Access
    A modified version of the Kolmogorov-Smirnov (KS) test is presented as a tool to assess whether a specified, although arbitrary, probability model is unsuitable to describe the underlying distribution of a set of observations. ...
  • Multivariate hybrid modelling of future wave-storms at the northwestern Black Sea 

    Lin Ye, Jue; García León, Manuel; Gracia Garcia, Vicente; Ortego Martínez, María Isabel; Stanica, Adrian; Sánchez-Arcilla Conejo, Agustín (2018-02)
    Article
    Open Access
    The characterization of future wave-storms and their relationship to large-scale climate can provide useful information for environmental or urban planning at coastal areas. A hybrid methodology (process-based and statistical) ...
  • Multivariate statistical modelling of future marine storms 

    Lin Ye, Jue; García León, Manuel; Gracia Garcia, Vicente; Ortego Martínez, María Isabel; Lionello, Piero; Sánchez-Arcilla Conejo, Agustín (2017-04)
    Article
    Open Access
    Extreme events, such as wave-storms, need to be characterized for coastal infrastructure design purposes. Such description should contain information on both the univariate behaviour and the joint-dependence of storm-variables. ...
  • Pluviometric regionalization of Catalunya: a compositional data methodology 

    Gibergans Bàguena, José; Ortego Martínez, María Isabel; Tolosana Delgado, Raimon (Centro Internacional de Métodos Numéricos en Ingeniería (CIMNE), 2011)
    Conference report
    Open Access
    The aim of this paper is to introduce a methodology for de¯ning groups from regionalized com- positional data, through a hierarchical clustering algorithm aware of both the spatial dependence and the compositional character ...
  • Relationship between popularity of key words in the Google browser and the evolution of worldwide financial indexes 

    ORTELLS SESÉ, ROBERT; Egozcue Rubí, Juan José; Ortego Martínez, María Isabel; Garola Crespo, Àlvar (2015)
    Conference report
    Open Access
    The purpose of this contribution is to evaluate whether there is enough statistical basis to establish a relationship between the popularity of certain terms in the Google, Inc. browser and the evolution of several worldwide ...
  • Relationship between the popularity of key words in the Google browser and the evolution of worldwide financial indices 

    Ortells Sesé, Robert; Egozcue Rubí, Juan José; Ortego Martínez, María Isabel; Garola Crespo, Àlvar (Springer, 2016)
    Part of book or chapter of book
    Restricted access - publisher's policy
    The authoritative contributions gathered in this volume reflect the state of the art in compositional data analysis (CoDa). The respective chapters cover all aspects of CoDa, ranging from mathematical theory, statistical ...
  • Rethinking the Kolmogorov-Smirnov test of Goodness of fit in a compositional way 

    Monti, Gianna S.; Mateu Figueras, Gloria; Ortego Martínez, María Isabel; Pawlowsky Glahn, Vera; Egozcue Rubí, Juan José (Pearson, 2018)
    Conference report
    Open Access
    The Kolmogorov Smirnov test (KS) is a well known test used to asses how a set of observations is significantly different from the probability model specified under the null hypothesis. The KS test statistic quantifies the ...