Encontrados 50 documentos, a visualizar página 1 de 5
Predicting seasonal and hydro-meteorological impact in environmental variables ...
Gonçalves, A.; Costa, MarcoThis study focuses on the potential improvement of environmental variables modelling by using linear state-space models, as an improvement of the linear regression model, and by incorporating a constructed hydro-meteorological covariate. The Kalman filter predic- tors allow to obtain accurate predictions of calibration factors for both seasonal and hydro-meteorological components. This methodology can be used t...
Change-point analysis in environmental time series
Gonçalves, A. Manuela; Costa, Marco; Teixeira, LaraChange-points are present in many environmental time series. Time variations in environmental data are complex and they can hinder the identification of the so-called change-points when traditional models are applied to this type of problems. In this study, it is proposed an alternative approach for the application of the change-point analysis by taking into account this data structure (seasonality and autocorr...
Metodologia estatística para a classificação das escolas secundárias em Portugal
Oliveira, Mário; Gonçalves, A. Manuela; Costa, MarcoNeste trabalho pretende-se efetuar um estudo, na área da Estatística, sobre a classificação das Escolas Secundárias (Portugal Continental e Ilhas) relativamente aos resultados alcançados pelos seus alunos nos Exames Nacionais. Tem-se como principal objetivo identificar grupos de Escolas com diferentes graus de desempenho considerando os subsistemas de ensino nacional público e privado, bem como a sua reg...
Calibration, selection and mosaicing of SMART-1 AMIE images
Costa, Marco António Bernardino RaimundoDissertação para obtenção do Grau de Mestre em Engenharia Electrotécnica e de Computadores ; Small Missions for Advanced Research in Technology (SMART-1), represented European Space Agency (ESA) first mission to the moon. It fulfilled the goal of improving the scientific knowledge of earth’s natural satellite, while testing new technologies that had never been used in space exploration. Among the on board inst...
Sistema de apoio à mobilidade de utilizadores da bicicleta
Costa, Marco André Ferreira daTese de mestrado integrado. Engenharia Informática e Computação. Universidade do Porto. Faculdade de Engenharia. 2011
Combining Statistical Methodologies in Water Quality Monitoring in a Hydrologic...
Costa, Marco; A. Manuela GonçalvesIn this work are discussed some statistical approaches that combine multivariate statistical techniques and time series analysis in order to describe and model spatial patterns and temporal evolution by observing hydrological series of water quality variables recorded in time and space. These approaches are illustrated with a data set collected in the River Ave hydrological basin located in the Northwest region...
Water monitoring sites discrimination using clustering water variables time ser...
Gonçalves. A. Manuela; Costa, MarcoApplication of multivariate methodologies for the evaluation and interpretation of space-time variations in an environmental monitoring data set from an hydrological basin is presented in this study. The results obtained allowed detecting natural clusters of monitoring sites with similar water quality type and identifying important discriminant variables for each cluster. Furthermore, this type of analysis allo...
Kalman filtering approach in the calibration of radar rainfall data: a comparat...
Costa, Marco; Monteiro, Magda; Gonçalves, A. ManuelaIn this chapter it is presented a comparative study of some methods to estimate radar rainfall in real time. This work in- tends to discuss and compare different state space formulations based on a same data set; for instance, the comparison between the mode- ling of the mean field radar rainfall logarithmic bias (Chumchean et al., 2006), a linear radar-rain gauge calibration model (Alpuim & Barbosa, 1999; Cost...
Information criterion on the change-point detection in water quality data
Gonçalves, A. Manuela; Costa, Marco; Teixeira, LaraThe number of studies using change-point methods to detect shifts has been increasing. The Schwarz Information Criterion SIC is used in this study to search for the change-point in time series of water quality variables.
A note on prediction bias for state space models with estimated parameters
Monteiro, Magda; Costa, MarcoThis paper aims to discuss some problems on state space models with estimated parameters. While existing research focus on the prediction mean squared error, this work presents some results on bias propagation into forecast and filter predictions when the mean vector of the state is taking with an estimation bias, namely, non recursive analytical expression for them. In particular, it is discussed the impact of...
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