Graciela Estévez-Pérez

University of A Coruña | UDC · Department of Mathematics

Comparison of emotion perception in music and prosody has the potential to contribute to an understanding of their speculated shared evolutionary origin. Previous research suggests shared sensitivity to and processing of music and speech, but less is known about how emotion perception in the auditory domain might be influenced by individual differe...

An integrative approach combining morphological, molecular and cytological information was used to assess the taxonomy and biogeography of Hierochloë section Monoecia. More specifically, we aimed to evaluate (1) if the morphological and molecular data are in concert with the current taxonomy of the group and (2) if speciation in this exclusively So...

In this study we analysed 26 macro and micromorphological characteristics in 31 species belonging to the subtribe Anthoxanthinae. Multivariate analysis methods were applied to select the phenotipic characteristics that allow us to classify the taxonomic relationships between the members of this complex group of plants.

Comparing the slopes of aqueous-based and standard addition calibration procedures is almost a daily task in analytical laboratories. As usual protocols imply very few standards sound statistical inference and conclusions are hard to obtain using current classical tests (e.g. the t-test), which may greatly affect decision-making. Following, there i...

Phytoplankton is a sentinel of marine ecosystem change. Composed by many species with different life-history strategies, it rapidly responds to environment changes. An analysis of the abundance of 54 phytoplankton species in Galicia (NW Spain) between 1989 and 2008 to determine the main components of temporal variability in relation to climate and...

Phytoplankton is a sentinel of marine ecosystem change. Composed by many species with different life-history strategies, it rapidly responds to environment changes. An analysis of the abundance of 54 phytoplankton species in Galicia (NW Spain) between 1989 and 2008 to determine the main components of temporal variability in relation to climate and...

Comparing the slopes of two regression lines is an almost daily task in analytical laboratories. The usual procedure is based on a Student's t-test although literature differs in whether the standard errors of the slopes or the standard errors of the regressions should be employed to get a pooled standard error. In this work fundamental concepts on...

A nonparametric functional approach is proposed to compare the mean functions of $k$ k samples of curves. In practice, curves data are usually collected in a discrete form and hence they must be pre-processed to use purely functional techniques. However, in the context of $k$ k -sample tests, the pre-processing step can have effects in term...

The R package kerdiest has been designed for computing kernel estimators of the distri-bution function and other related functions. Because of its usefulness in real applications, the bandwidth parameter selection problem has been considered, and a cross-validation method and two of plug-in type have been implemented. Moreover, three relevant func-...

In the present study, several multivariate analyses were carried out to assess the taxonomic relationships among European species of the genus Anthoxanthum. A total of 1787 Anthoxanthum specimens representing all European taxa were analyzed. Thirty macro-morphological (13 quantitative and 17 qualitative) and 29 micro-morphological (7 quantitative a...

Prediction of maximum ozone concentration is of great importance, especially to alert the population and to allow the authorities to take preventive measures soon enough. Ozone concentration and meteoro-logical variables are now observed each hour or every 10 min so that we nearly get continuous observations along time, i.e. functions, as covariate...

Modelling dependence structure by means of long memory processes appears of great interest for many applications. This paper aims to show how nonparametric kernel estimators behave asymptotically under this dependence structure. We will consider a wide class of functional estimation problems, including distribution function, hazard function and den...

Les travaux existant en matière d'estimation fonctionnelle de processus se font en général sous une hypothèse de courte dépendance (de type mélange par exemple) qui permet d'obtenir des vitesses de convergence analogues à celles obtenues pour des échantillons indépendants. Cette Note se propose de présenter des résultats asymptotiques pour plusieur...

As an alternative to traditional parametric approaches, we suggest nonparametric methods for analyzing temporal data on earthquake occurrences. In particular, the kernel method for estimating the hazard function and the intensity function are presented. One novelty of our approaches is that we take into account the possible dependence of the data t...

This paper is devoted to the nonparametric estimation of hazard function by means of kernel smoothers, and more specifically to the crucial problem of bandwidth selection. We first get the convergence rate of usual cross-validated bandwidth under a general dependence assumption on the sample data, extending in several directions the results existin...

Vieu (J. Multivariate Anal. 39 (1991) 324) showed that the quadratic errors for kernel estimates of several curves (including distribution and hazard functions) are asymptotically equivalent under strong mixing conditions. In this paper, the convergence rates of the distances between these quadratic errors are investigated in the particular case of...

We study the nonparametric estimation of the risk or hazard function of a real random variable. Through an uncensored random sample of data X1, X2,...,Xn, not necessarily independent, we consider an estimator built as a ratio of a kernel estimator of the density function and a kernel estimator of the survival function. We consider the bandwidth sel...

Se estudia la estimación de tipo no paramétrico de la función de riesgo o razón de fallo de una variable aleatoria real. A partir de una muestra X1, X2, ..., Xn de datos no censurados y no necesariamente independientes, se considera un estimador cociente entre el estimador núcleo de la función de densidad y un estimador núcleo de la función de supe...

The estimation of the hazard rate has a great number of practical appli¬cations in dependence situations (seismicity analysis, reliability, economics), Based on kernel estimates of the density and the distribution function, we study the properties of the nonparametric estimator of the hazard function as-sociated with a strongly mixing time series....

The study of seismic series for the searching of some parameter that characterizes them, constitutes a field of great difficulty. In this work three series of different seismic zones from Andalusia are analyzed, the series of Agrón (1988-1989), the series of Antequera (1989) and the series of Iznajar (1998). The time dependent data used for each ea...