Now showing items 1-20 of 42

    • A posteriori error estimation for standard finite element analysis 

      Díez, Pedro; Egozcue Rubí, Juan José; Huerta, Antonio (1998-09)
      Article
      Open Access
      A new residual type estimator based on projections of the error on subspaces of locally-supported functions is presented. The estimator is defined by a standard element-by-element refinement. First, an approximation of the ...
    • Air quality index revisited from a compositional point of view 

      Jarauta Bragulat, Eusebio; Hervada Sala, Carme; Egozcue Rubí, Juan José (2016-06)
      Article
      Open Access
      The so-called Air Quality Index (AQI), expresses the quality of atmospheric air. The overall AQI is determined from the AQIs of some reference air pollutants, which are calculated by a transform of the respective concentrations. ...
    • 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) ...
    • Balances: a new perspective for microbiome analysis 

      Rivera Pinto, J.; Egozcue Rubí, Juan José; Pawlowsky Glahn, Vera; Paredes, Raul; Noguera Julian, Marc; Calle, M. L. (2018-07)
      Article
      Open Access
      High-throughput sequencing technologies have revolutionized microbiome research by allowing the relative quantification of microbiome composition and function in different environments. In this work we focus on the ...
    • Bayes linear spaces 

      Van den Boogaart, Karl Gerard; Egozcue Rubí, Juan José; Pawlowsky-Glahn, Vera (2010-12)
      Article
      Open Access
      Linear spaces consisting of $\sigma$-finite probability measures and infinite measures (improper priors and likelihood functions) are defined. The commutative group operation, called perturbation, is the updating given by ...
    • 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 ...
    • 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 ...
    • Classifying wave forecasts with model-based geostatistics and the Aitchison distribution 

      Tolosana Delgado, Raimon; Egozcue Rubí, Juan José; Sánchez-Arcilla Conejo, Agustín; Gómez Aguar, Jesús Javier (2010)
      Conference report
      Restricted access - publisher's policy
    • 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 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 ...
    • Descripción del oleaje por el método de las direcciones instantáneas 

      Arribas Perea, Miguel Ángel; Egozcue Rubí, Juan José (1992-12)
      Article
      Open Access
      Se presenta el método de las direcciones instantáneas para la descripción del oleaje. El punto de partida es el hecho de que las series temporales de la elevación de la superficie del mar contienen más información que la ...
    • Estimació del pol i de la variància del soroll d'un model AR(1) mitjançant filtratge no lineal 

      Muñoz Gracia, María del Pilar; Martí Recober, Manuel; Egozcue Rubí, Juan José (Universitat Politècnica de Barcelona. Centre de Càlcul, 1988)
      Article
      Open Access
      L'estimació dels paràmetres associats a un procés ARMA es pot plantejar com un problema de filtratge no lineai. Per determinar un estimador recursiu d'aquests paràmetres es deflneix un vector d'estat ampliat que inclou les ...
    • Estimación del parámetro b de Richter a partir de las medidas imprecisas de intensidad epicentral 

      Forcada Plaza, Santiago; Egozcue Rubí, Juan José (Institut d'estadística de Catalunya, 1996)
      Article
      Open Access
      El objetivo de este trabajo es la estimación del parámetro exponencial de Richter que determina la distribución de probabilidad de la variable intensidad de movimientos sísmicos que se producen en una determinada zona. Las ...
    • Evidence functions: a compositional approach to information 

      Egozcue Rubí, Juan José; Pawlowsky Glahn, Vera (Institut d'Estadística de Catalunya, 2018-07-01)
      Article
      Open Access
      The discrete case of Bayes’ formula is considered the paradigm of information acquisition. Prior and posterior probability functions, as well as likelihood functions, called evidence functions, are compositions following ...
    • Exploration of geochemical data with compositional canonical biplots 

      Graffelman, Jan; Pawlowsky Glahn, Vera; Egozcue Rubí, Juan José; Buccianti, A. (2018-07-25)
      Article
      Restricted access - publisher's policy
      The study of the relationships between two compositions is of paramount importance in geochemical data analysis. This paper develops a compositional version of canonical correlation analysis, called CoDA-CCO, for this ...
    • Long-term impact of fecal transplantation in healthy volunteers 

      Goloshchapov, Oleg V.; Olekhnovich, Evgenii I.; Sidorenko, Sergey V.; Egozcue Rubí, Juan José (2019-12)
      Article
      Open Access
      Fecal microbiota transplantation (FMT) has been recently approved by FDA for the treatment of refractory recurrent clostridial colitis (rCDI). Success of FTM in treatment of rCDI led to a number of studies investigating ...
    • Microbiome datasets are compositional: and this is not optional 

      Gloor, Gregory B.; Macklaim, Jean M.; Pawlowsky Glahn, Vera; Egozcue Rubí, Juan José (2017-11)
      Article
      Open Access
      Datasets collected by high-throughput sequencing (HTS) of 16S rRNA gene amplimers, metagenomes or metatranscriptomes are commonplace and being used to study human disease states, ecological differences between sites, and ...