• openAccess   A spatial randomness test based on the box-counting dimension 

      Caballero, Yolanda; Giraldo, Ramón; Mateu, Jorge Springer (2022)
      Statistical modelling of a spatial point pattern often begins by testing the hypothesis of spatial randomness. Classical tests are based on quadrat counts and distance-based methods. Alternatively, we propose a new statistical ...
    • closedAccess   A universal kriging approach for spatial functional data 

      Caballero, William; Giraldo, Ramón; Mateu, Jorge Springer (2013-02)
      In a wide range of scientific fields the outputs coming from certain measurements often come in form of curves. In this paper we give a solution to the problem of spatial prediction of non-stationary functional data. We ...
    • closedAccess   Analysis of variance for spatially correlated functional data: Application to brain data 

      Aristizabal, Jeimy-Paola; Giraldo, Ramón; Mateu, Jorge Elsevier (2019)
      Functional data showing spatial dependence structure occur in many applied fields. For example, in meteorology when curves of temperature are obtained in a monitoring network, or in neurological studies when curves of the ...
    • openAccess   Geofd: An R Package for Function-Valued Geostatistical Prediction 

      Giraldo, Ramón; Mateu, Jorge; Delicado, Pedro Universidad Nacional de Colombia (2015-12)
      Spatially correlated curves are present in a wide range of applied disciplines. In this paper we describe the R package geofd which implements ordinary kriging prediction for this type of data. Initially the curves ...
    • openAccess   Hierarchical clustering of spatially correlated functional data 

      Giraldo, Ramón; Delicado, Pedro; Mateu, Jorge John Wiley & Sons (2012-11)
      Classification problems of functional data arise naturally in many applications. Several approaches have been considered for solving the problem of funding groups based on functional data. In this paper we are interested ...
    • openAccess   High leverage detection in general functional regression models with spatially correlated errors 

      Romano, Elvira; Giraldo, Ramón; Mateu, Jorge; Diana, Andrea Wiley (2021)
      The presence of curves that deviate markedly from the core of a set of curves can greatly affect inference and forecasting in a functional regression model. Thus their detection is key to increase the accuracy of the ...
    • closedAccess   Kriging with external drift for functional data for air quality monitoring 

      Ignaccolo, Rosaria; Mateu, Jorge; Giraldo, Ramón Springer Verlag (2014-07)
      Functional data featured by a spatial dependence structure occur in many environmental sciences when curves are observed, for example, along time or along depth. Recently, some methods allowing for the prediction of a curve ...
    • closedAccess   Multivariate functional random fields: prediction and optimal sampling 

      Bohorquez Castañeda, Martha Patricia; Giraldo, Ramón; Mateu, Jorge Springer Verlag (2017)
      This paper develops spatial prediction of a functional variable at unsampled sites, using functional covariates, that is, we present a functional cokriging method. We show that through the representation of each function ...
    • closedAccess   On the performance of two clustering methods for spatial functional data 

      Romano, Elvira; Mateu, Jorge; Giraldo, Ramón Springer Verlag (2015-10)
      The performance of two clustering strategies for spatially correlated functional data based on the same measure of spatial dependence is examined and compared. In particular, the role of the spatial dependence computed by ...
    • closedAccess   Optimal dynamic spatial sampling 

      Bohorquez Castañeda, Martha Patricia; Giraldo, Ramón; Mateu, Jorge John Wiley & Sons Ltd (2016)
      This paper provides new tools for dynamic spatial sampling designs to find the optimal spatial mean estimation and the optimal spatial prediction, based on the temporal variation of the spatial dependence structure. We ...
    • openAccess   Residual kriging for functional data. Application to the spatial prediction of salinity curves 

      Reyes, Adriana; Giraldo, Ramón; Mateu, Jorge Taylor & Francis (2015)
      Recently several methodologies for carrying out geostatistical analysis of functional data has been proposed. All of them assume that the spatial functional process considered is stationary. However in practice we often ...
    • closedAccess   Statistics for spatial functional data: some recent contributions 

      Delicado, Pedro; Giraldo, Ramón; Comas Rodríguez, Carlos; Mateu, Jorge John Wiley & Sons, Ltd. (2010)
      Functional data analysis (FDA) is a relatively new branch in statistics. Experiments where a complete function is observed for each individual give rise to functional data. In this work we focus on the case of functional ...