Now showing items 1-20 of 398

    • 40 years after Aitchison’s article “The statistical analysis of compositional data”. Where we are and where we are heading 

      Coenders, Germà; Egozcue, Juan José; Fačevicová, Kamila; Navarro-López, Carolina; Palarea-Albaladejo, Javier; Pawlowsky-Glahn, Vera (Institut d'Estadística de Catalunya, 2023-11-22)
      Article
      Open Access
      The year 2022 marked 40 years since Aitchison published the article “The statistical analysis of compositional data”. It is considered to be the foundation of contemporary compositional data analysis. It is time to review ...
    • A combined and robust modal-split/traffic assignment model for rail and road freight transport 

      Rosell Camps, Francisca; Codina Sancho, Esteve; Montero Mercadé, Lídia (2022-12-01)
      Article
      Open Access
      Searching for achieving an ambitious reduction in greenhouse gas emissions, the EU has set as a goal a modal shift in freight transport of 30% by rail for the near future. In this context, it is vital to use modal choice ...
    • A comparison between machine learning and classic algorithms for GDP forecast 

      Monar Aguilar, Kenny Xavier (Universitat Politècnica de Catalunya / Universitat de Barcelona, 2022-10)
      Master thesis
      Open Access
      In the recent years there has been an explosive increase in the number of research papers using machine learning methods for forecasting. In this work, I will focus on comparing the estimation of GDP using classical and ...
    • A comparison of some confidence intervals for estimating the population coefficient of variation: a simulation study 

      Gulhar, Monika; Golam Kibria, B.M.; Albatineh, Ahmed; Ahmed, Nasar U (Institut d'Estadística de Catalunya, 2012)
      Article
      Open Access
      This paper considers several confidence intervals for estim ating the population coefficient of variation based on parametric, nonparametric and modified m ethods. A simulation study has been conducted to compare the ...
    • A Compositional Approach to Allele Sharing Analysis 

      Galván Femenía, Iván; Graffelman, Jan (Springer, 2016)
      Part of book or chapter of book
      Restricted access - publisher's policy
      Relatedness is of great interest in population-based genetic association studies. These studies search for genetic factors related to disease. Many statistical methods used in population-based genetic association studies ...
    • A Decomposition-Ensemble framework for oil price forecasting during Covid19 outbreak: enabling rapid response in IOCs and NOCs 

      Ruiz Partida, Angel (Universitat Politècnica de Catalunya / Universitat de Barcelona, 2021-10)
      Master thesis
      Open Access
      One of main economic impacts of Covid19 was the unprecedented drop in crude futures prices. After the crash, a high-volatility period followed, adding more uncertainty to the markets and financial institutions worldwide. ...
    • A diffusion-based spatio-temporal extension of Gaussian Matérn fields 

      Lindgren, Finn; Bakka, Haakon; Bolin, David; Krainski, Elias; Rue, Håvard (Institut d'Estadística de Catalunya, 2024-05-09)
      Article
      Open Access
      Gaussian random fields with Matérn covariance functions are popular models in spatial statistics and machine learning. In this work, we develop a spatio-temporal extension of the Gaussian Matérn fields formulated as solutions ...
    • A genome-wide study of Hardy–Weinberg equilibrium with next generation sequence data 

      Graffelman, Jan; Jain, Deepti; Weir, B.S. (2017-04-03)
      Article
      Open Access
      Statistical tests for Hardy–Weinberg equilibrium have been an important tool for detecting genotyping errors in the past, and remain important in the quality control of next generation sequence data. In this paper, we ...
    • A log-ratio biplot approach for exploring genetic relatedness based on identity by state 

      Graffelman, Jan; Galván Femenía, Iván; de Cid, Rafael; Barceló Vidal, Carles (2019-04-24)
      Article
      Open Access
      The detection of cryptic relatedness in large population-based cohorts is of great importance in genome research. The usual approach for detecting closely related individuals is to plot allele sharing statistics, based on ...
    • A methodology for maintaining consistency between conceptual interpretations of nested partitions 

      Sevilla-Villanueva, Beatriz; Gibert, Karina; Sànchez-Marrè, Miquel (2016)
      Conference report
      Restricted access - publisher's policy
      The relationship between interpretations of nested partitions is analyzed in this work, since there are multiple situations where a refinement of the original partition arises. As a result, a new methodology NCI-IMS is ...
    • A microbiology application of the skew-Laplace distribution 

      Julià, Olga; Vives Rego, Josep (Institut d'Estadística de Catalunya, 2008)
      Article
      Open Access
      Flow cytometry scatter are ofen used in microbiology, and their measures are related to bacteria size and granularity. We present an application of the skew-Laplace distribution to flow cytometry data. The goodness of fit ...
    • A mixture model application in monitoring error message rates for a distributed industrial fleet 

      Plandolit López, Bernat; Puig de Dou, Ignacio; Costigan, Gráinne; Puig Oriol, Xavier; Rodero de Lamo, Lourdes; Martínez Martínez, José Miguel (2022-11-01)
      Article
      Open Access
      Remotely monitoring industrial printers for an unexpected increase of warning and error messages reduces equipment downtime and increases customer satisfaction. Directly tracking raw error messages rates during a given ...
    • A new spectral method for latent variable models 

      Ruffini, Matteo; Casanellas Rius, Marta; Gavaldà Mestre, Ricard (2018-05-22)
      Article
      Open Access
      We present an algorithm for the unsupervised learning of latent variable models based on the method of moments. We give efficient estimates of the moments for two models that are well known, e.g., in text mining, the ...
    • A note on interval estimation for the mean of inverse Gaussian distribution 

      Arefi, M.; Mohtashami Borzadaran, G.R.; Vaghei, Y. (Institut d'Estadística de Catalunya, 2008)
      Article
      Open Access
      In this paper, we study the interval Estimation for the mean from inverse Gaussian distribution. This distribution is a member of the natural exponential families with cubic variance function. Also, we simulate the coverage ...
    • A note on the likelihood and moments of the skew-normal distribution 

      Martínez, E. H.; Varela, H.; Gómez, H. W.; Bolfarine, Heleno (Institut d'Estadística de Catalunya, 2008)
      Article
      Open Access
      In this paper an alternative approach to the one in Henze (1986) is proposed for deriving the odd moments of the skew-normal distribution considered in Azzalini (1985). The approach is based on a Pascal type triangle, which ...
    • A planning solution for forecasting product sales with cannibalization 

      Ibáñez Prat, Ferran (Universitat Politècnica de Catalunya / Universitat de Barcelona, 2022-01)
      Master thesis
      Open Access
      Covenantee:   Accenture
      Predicting sales using cannibalization effects is a current major challenge. Several approaches deal with the estimation of cannibalization of new product launches or promotion effects but how to account for it when ...
    • A simulation study on some confidence intervals for the population standard deviation 

      Abu-Shawiesh, Moustafa Omar Ahmed; Banik, Shipra; Golam Kibria, B. M. Golam Kibria (Institut d'Estadística de Catalunya, 2011)
      Article
      Open Access
      In this paper a robust estimator against outliers along with some other existing interval estimators are considered for estimating the population standard devi ation. An extensive simulation study has been conducted ...
    • A simulation system for intermodal assignment of public transport and ride pooling services 

      Lorente García, Ester; Barceló Bugeda, Jaume; Codina Sancho, Esteve; Klaus, Nökel (2022)
      Conference report
      Restricted access - publisher's policy
    • A statistical learning based approach for parameter fine-tuning of metaheuristics 

      Calvet Liñán, Laura; Juan Pérez, Ángel Alejandro; Serrat Piè, Carles; Ries, Jana (2016-06)
      Article
      Open Access
      Metaheuristics are approximation methods used to solve combinatorial optimization problems. Their performance usually depends on a set of parameters that need to be adjusted. The selection of appropriate parameter values ...
    • A survey exploring biomedical editors’ perceptions of editorial interventions to improve adherence to reporting guidelines 

      Blanco de Tena Davila, David; Hren, Darko; Kirkham, Jamie J.; Cobo Valeri, Erik; Schroter, Sara (2019-09-24)
      Article
      Open Access
      Background: Improving the completeness of reporting of biomedical research is essential for improving its usability. For this reason, hundreds of reporting guidelines have been created in the last few decades but adherence ...