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In this paper we introduce two procedures for variable selection in cluster analysis and classification rules. One is mainly oriented to detect the " noisy " non–informative variables, while the other deals also with multicolinearity. A forward–backward algorithm is also proposed to make feasible these procedures in large data sets. A small simulation is(More)
Aim There is an urgent need for conservation in threatened tropical forest regions. We explain and predict the spatial variation of α (i.e. within plot) and β (i.e. between plot) tree diversity in a tropical montane landscape subjected to a high deforestation rate. A major aim is to demonstrate the potential of a method that combines data from multiple(More)
A principal component method for multivariate functional data is proposed. Data can be arranged in a matrix whose elements are functions so that for each individual a vector of p functions is observed. This set of p curves is reduced to a small number of transformed functions, retaining as much information as possible. The criterion to measure the(More)
Human activity and specifically tourism has been increasing in Antarctica over the last few years. Few studies have examined the indirect effects of human visits on Antarctic penguin rookeries. This work aims to study the differences between a highly visited (Hannah Point) and a rarely visited (Devil's Point, Byers Peninsula) gentoo penguin rookery on(More)
The present study shows the occurrence of remarkable interannual variation in the meteorological conditions at Byers Peninsula (Livingston Island, South Shetlands Islands, Antarctica), in which one of the summers was significantly colder than the others. Within this climatic scenario, a limnological study was carried out at Lake Limnopolar during three(More)
The Spanish Antarctic Station Juan Carlos I has been registering surface air temperatures with the frequency of one reading per 10 min since the austral summer 1987–1988. Although this data set contains valuable information about the climate patterns in and around Antarctica, it has not been utilized in any existing climate studies thus far because of the(More)
In 2001 the LIMNOPOLAR Project was launched with the aim of addressing the suitability of freshwater ecosystems as useful sentinels of climate change. In this project, an automatic weather station was deployed on Byers Peninsula (Livingston Island, South Shetland Islands) near several freshwater ecosystems under research. Here the multi-year data recorded(More)
This paper considers the estimation of a set S < d from a random sample of n points, using the \naive" estimator ^ Sn (the simplest one for the non-convex case) deened as a union of balls, centered at the sample points, with common radius n. In particular, we f o c u s o n further exploring a method, rst proposed by Devroye and Wise (1980), for the(More)
A new clustering method for time series is proposed, based on the full probability density of the forecasts. First, a resampling method combined with a nonparametric kernel estimator provides estimates of the forecast densities. A measure of discrepancy is then defined between these estimates and the resulting dissimilarity matrix is used to carry out the(More)