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  • Name

    Adelaide Figueiredo
  • Cluster

    Computer Science
  • Role

    Senior Researcher
  • Since

    01st December 2011
Publications

2017

Clustering Directions Based on the Estimation of a Mixture of Von Mises-Fisher Distributions

Authors
Figueiredo, A;

Publication
The Open Statistics & Probability Journal

Abstract

2017

Bootstrap and permutation tests in ANOVA for directional data

Authors
Figueiredo, A;

Publication
COMPUTATIONAL STATISTICS

Abstract
The problem of testing the null hypothesis of a common direction across several populations defined on the hypersphere arises frequently when we deal with directional data. We may consider the Analysis of Variance (ANOVA) for testing such hypotheses. However, for the Watson distribution, a commonly used distribution for modeling axial data, the ANOVA test is only valid for large concentrations. So we suggest to use alternative tests, such as bootstrap and permutation tests in ANOVA. Then, we investigate the performance of these tests for data from Watson populations defined on the hypersphere.

2016

ANALYSIS OF WELL-BEING IN OECD COUNTRIES THROUGH STATIS METHODOLOGY

Authors
Rivadeneira, FJ; Figueiredo, AMS; Figueiredo, FOS; Carvajal, SM; Rivadeneira, RA;

Publication
HOLOS

Abstract
This paper presents the main concepts and results of a Master thesis in Data Analysis which aims to analyze the evolution of some developed countries and also of some emerging countries that are members of the Organisation for Economic Co-operation and Development (OECD) in what concerns some indicators or variables of well-being during the period 2011-2015, through the STATIS (Structuring Three-way data sets in Statistics) methodology. This methodology allows to analyze the presence of a common structure in several data tables obtained over time, to identify the differences and similarities along the period of time under study and according to well-being indicators included in the "Your Better Life Index" of the OECD, and to analyze the trajectories of the countries.

2015

Clustering of Variables Based on Watson Distribution on Hypersphere: A Comparison of Algorithms

Authors
Figueiredo, A; Gomes, P;

Publication
COMMUNICATIONS IN STATISTICS-SIMULATION AND COMPUTATION

Abstract
We consider n individuals described by p variables, represented by points of the surface of unit hypersphere. We suppose that the individuals are fixed and the set of variables comes from a mixture of bipolar Watson distributions. For the mixture identification, we use EM and dynamic clusters algorithms, which enable us to obtain a partition of the set of variables into clusters of variables.Our aim is to evaluate the clusters obtained in these algorithms, using measures of within-groups variability and between-groups variability and compare these clusters with those obtained in other clustering approaches, by analyzing simulated and real data.

2014

Comparison of Sampling Plans by Variables using the Bootstrap and Monte Carlo Simulations

Authors
Figueiredo, F; Figueiredo, A; Gomes, MI;

Publication
INTERNATIONAL CONFERENCE OF COMPUTATIONAL METHODS IN SCIENCES AND ENGINEERING 2014 (ICCMSE 2014)

Abstract
We consider two sampling plans by variables to inspect batches of products from an industrial process under a context of unknown distribution underlying the measurements of the quality characteristic under study. Through the use of the bootstrap methodology and Monte Carlo simulations we evaluate and compare the performance of those sampling plans in terms of probability of acceptance of lots and average outgoing quality level.

Supervised
thesis

2017

Export assistance programmes: differences between advanced and emerging economies

Author
Joana Soqueiro Ribeiro

Institution
UP-FEP

2017

Previsão de tempos cirúrgicos num hospital

Author
Sílvia Susana de Moura Carvalho

Institution
UP-FEP

2016

Analysis of OECD Countries Well-being through Statis Methodology

Author
Fabricio Javier Rivadeneira Zambrano

Institution
UP-FEP

2015

Monitorização de processos usando uma abordagem não paramétrica

Author
César Duarte Alves da Rocha

Institution
UP-FCUP

2015

Controlo de Infeções Hospitalares através de Cartas de Controlo

Author
Miguel Andrade do Vale

Institution
UP-FEP