Browsing by Author "Oliveira, Teresa A."
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- 12th Workshop on Statistics, Mathematics and Computation In Honour of Professor Carlos Braumann: book of abstractsPublication . Oliveira, Amilcar; Nunes, Célia; Ferreira, Dário; Grilo, Luís M.; Ferreira, Sandra; Oliveira, Teresa A.We celebrate this meeting in Honour of Professor Carlos Braumann, for his brilliant career and outstanding contribution to the field of Statistics in Portugal and abroad, and to whom we are deeply grateful for all the support, kind and precious collaboration in our meetings! We are delighted to have this celebration fostering strong interaction between national and international researchers, leading to a successful com mitment and enthusiasm on promoting research in and between the broad areas of Statistics, Mathematics and Computation. It is a great pleasure to receive all our guests and contributors from 9 to 10 th November in UBI Universidade da Beira Interior, expressing our huge gratitude to the Univer sity Coordinators for kindly accepted to embrace this challenge of receiving us again! The WSMC was successfully organized in several places along these last 12 years and we believe that our meetings have been creating very nice opportunities for showcasing the growth and development of the focused main areas, at a time when so many new technologies are available and huge challenges are emerging. The idea exchanges between participants are al ways helpful for generating positive impact on propelling the advancement of science and technology and some of these results have been published in high standard Journals, special issues and Springer Series Books. Also in this 12th WSMC edition the participants will have several journal oppor tunities for papers submission. Selected papers, after review, will appear in Journal of Applied Statistics, Biometrical Letters, Biometrics & Biostatis tics International Journal (BBIJ) and in a new Springer volume of the Series Contributions to Statistics. We are hightly grateful to all the participants, Invited Speakers, Session Organizers and Authors who submitted abstracts, for their valuable contri bution and for the enthusiastic way how they assume their participation. We also acknowledge all the sponsors and contributors who made this meeting a reality. Furthermore, we acknowledge the Rector of Universidade da Beira Interior, the Rector of Universidade Aberta, the Coordinator of the Centro de Estatística e Aplicações da Universidade de Lisboa and the President of the Committee on Risk Analysis of International Statistical Institute, for v vi Preface their support. We are most grateful to all the members of the Organizing Committee and of the Scientific Committee for their crucial help and sugges tions. We address a deeply thanks to the Local Chair, Sandra Ferreira, and also to Amílcar Oliveira, Célia Nunes, Dário Ferreira and Luís Grilo for their invaluable contribution on organizing the Webpage, the final programme, the Book of Abstracts and so many details in a such incredible short time! Finally, the venue adds an important attraction to the meeting. The destination city, Covilhã, is a fantastic place close to beautiful and highest mountain in Portugal, Serra da Estrela. This region is very famous not only for awesome landscapes and sports opportunities but also for the famous de lights like the wool cheese, ham, licors and also for the traditional artesanat. Covilhã offers a full calendar of traditional festivals and holidays celebrated throughout the year adds to its cultural appeal. We trust that you will find the conference and your visit to the very beautiful city of Covilhã in November 2018 both valuable and enjoyable, we believe that this meeting will be rewarding to all of us and that it will draw us to the next edition -WSMC13, which is planned for 2019 in Lisbon.
- 13th Conference on Statistics, Mathematics and Computation: book of abstractsPublication . Oliveira, Amilcar; Ferreira, Dário; Ferreira, Sandra; Oliveira, Teresa A.We celebrate this meeting in Honour of Professor João Tiago Mexia, for his brilliant career and outstanding contribution to the field of Statistics in Portugal and abroad, and to whom we are deeply grateful for all the support, kindness and precious collaboration in our meetings! We are delighted to have this celebration, fostering strong interaction between national and international researchers, leading to a successful com mitment and enthusiasm on promoting research in and between the broad areas of Statistics, Mathematics and Computation. It is a great pleasure to receive all our guests and contributors from 3 to 5th June in the Aberta University, and we emphasize our huge gratitude to the Magnificent Rector, for kindly accepting to embrace this challenge of hosting once more this International Conference! The WSMC was successfully organized in several places along the 13 editions and we believe that our meetings have been creating very nice op portunities for showcasing the growth and development of the focused main areas, in a time underlined by so many new technologies and huge emerging challenges. The scientific exchanges of ideas between participants is always helpful for generating positive impact on propelling the advancement of sci ence and technology and some of these results have already been successfully published in high standard Journals, special issues and Springer Series Books. Also now, in this 13th edition, the participants have the opportunity to submit their work to high referenced Journals and Book volumes. Selected papers, after peer review, will appear in the Chilean Journal of Statistics (ChJS), Journal of Applied Statistics (JAS), Biometrical Letters, Biometrics & Biostatistics International Journal (BBIJ) and in Springer volumes of the Series Contributions to Statistics. Details will be soon announced in our webpage. We are highly grateful to all the participants, Invited Speakers, members of Scientific Committee, Session Organizers and Authors who submitted ab v vi Preface stracts, for their valuable contribution and for the enthusiastic way how their participation is assumed! We greatly acknowledge all the sponsors and contributors who made this meeting a reality and we reinforce the importance of our social programme. This year it includes the nice opportunity to visit the National Museum of Natural History and Science and the Botanical Garden, allowed all the week, from 3 to 9 of June - during and after WSMC13. We are really grateful to the Director of the Department of Museums Management Support and IICT, Dr Vitor Lucas and to his team, for kindly offering this outstanding opportunity to all the participants of WSMC13. A deeply thanks is addressed to all the members of the Organizing Com mittee, emphasizing the invaluable collaboration of Dr. Virginia Zaidam, the crucial help of the Gabinete de Comunicação e de Relações Internacionais UAB team, and the very hard work of Amílcar, Sandra and Dário on the organization and supervision of many of the programme and schedule de tails, preparing the website and the abstracts book in an incredible record time! Finally, as I guess most of you already noticed, Lisbon is very much enjoyable for offering a rich and varied history, a buzzing nightlife and for being blessed with a glorious year-round climate, where the sky joins the ocean and the city is kissed by the river Tagus. Please take some of your time to enjoy and take profit of it! Don’t forget to taste the famous "Pastéis de Belém" and to listen to Fado music! We wish you all a very productive and successfull meeting, as well as a pleasant and memorable stay in Lisbon, the stunning capital of Portugal!
- Analysis of residuals and adjustment in JRAPublication . Oliveira, Amilcar; Mexia, João Tiago; Oliveira, Teresa A.Joint Regression Analysis (JRA) is based in linear regression applied to yields, adjusting one linear regression per cultivar. The environmental indexes in JRA correspond to a non observable regressor which measures the productivity of the blocks in the field trials. Usually zig-zag algorithm is used in the adjustment. In this algorithm, minimizations for the regression coefficients alternate with those for the environmental indexes. The algorithm has performed very nicely but a general proof of convergence to the absolute minimum of the sum of squares of residues is still lucking. We now present a model for the residues that may be used to validate the adjustments carried out by the zig-zag algorithm.
- Analysis of the inequality into distributions: an alternative approach to the Gini index applied to the spending environmental in EUPublication . Seijas-Macias, Antonio; Oliveira, Amilcar; Oliveira, Teresa A.The Gini index is the most common tool to measure inequality into two distributions. Traditionally, the Gini index and the curve of Lorenz are focused on inequalities measures in the income distribution between countries or regions. But, in the last years, several authors have shown some limitations of the Gini index. In particular, it’s less sensitive to inequality at the tail of income distribution. This type of problem in the Gini index could produce two types of reactions: a new reinterpretation of the Gini index and the proposal of some alternative measures to it. In this paper, we follow the previous work using the Csiszar f-divergence to propose using the α-divergences approach to analyze the differences between the Gini index approach and these alternatives. The Gini index has been applied to the measure of resource inequalities. The AR-Gini is an area-based measure of resource inequality that estimates inequalities between neighbourhoods regarding the consumption of specific consumer goods (Druckman and Jackson, 2008). The AR-Gini could be a useful tool to monitor the distributional impacts of resource-related interventions, but this indicator presents the same overcomes as the Gini index. We can use the Gini concentration coefficient as a measure of the concentration of distribution of a random variable, especially applied to time series of data. In recent years, several studies have studied environmental spending in the European Union (EU). We focus our analysis on the distribution of this type of spending between the countries of the EU. The objective of this study is to show the differences in indexes applied to the study of the distribution of the distribution of monetary resources to environmental conservation and the extension of environmental protected areas into the countries of the European Union (EU). In our comparative study, we use the Gini index and the α-divergence measure and compare the results to get the most accurate measure of the equity of the distribution.
- Application of BIBDR in health sciences using RPublication . Oliveira, Amilcar; Oliveira, Teresa A.The role of Experimental Design is very well known, considering applications to a broad range of areas, such as Agriculture, Biology, Medicine, Industry, Education, Economy, Engineering and Food Consumption Sciences. Motivated by the variety of problems faced in the several areas and simultaneously taking advantage of the emerging technological developments, new theoretical results, as well as new designs and structures, have been developed by researchers and practitioners accordingly to the needs. Experimental Design got a place among the most important statistical methodologies and, mainly because of allowing to separate variation sources, since the last century it has been strongly recommended for Health Sciences studies. In this area, particular attention has been devoted to Randomized Complete Block Designs and to Balanced Incomplete Block Designs (BIBD) - which allow testing simultaneously a number of treatments bigger than the block size. Thus, after a brief review of some particular BIBD properties and of BIBDR - Balanced Incomplete Blocks with Block Repetition, an applications to Health Sciences simulated data is illustrated, by exploring R software
- Application of information geometry in incomplete block designs: towards statistical efficiencyPublication . Cardoso, Carla; Oliveira, Amilcar; Oliveira, Teresa A.
- Approximating the distribution of the product of two normally distributed random variablesPublication . Seijas-Macias, J. Antonio; Oliveira, Amilcar; Oliveira, Teresa A.; Leiva, VictorThe distribution of the product of two normally distributed random variables has been an open problem from the early years in the XXth century. First approaches tried to determinate the mathematical and statistical properties of the distribution of such a product using different types of functions. Recently, an improvement in computational techniques has performed new approaches for calculating related integrals by using numerical integration. Another approach is to adopt any other distribution to approximate the probability density function of this product. The skew-normal distribution is a generalization of the normal distribution which considers skewness making it flexible. In this work, we approximate the distribution of the product of two normally distributed random variables using a type of skew-normal distribution. The influence of the parameters of the two normal distributions on the approximation is explored. When one of the normally distributed variables has an inverse coefficient of variation greater than one, our approximation performs better than when both normally distributed variables have inverse coefficients of variation less than one. A graphical analysis visually shows the superiority of our approach in relation to other approaches proposed in the literature on the topic.
- Assessing dental symmetry: introduction of the Symmetry Measure Score (SMS) in periodontal disease analysisPublication . Pereira, J. A.; Mubayi, Anuj; Carvalho, Davide; Oliveira, Teresa A.
- BIB designs with repeated blocks: review and perspectivesPublication . Oliveira, Teresa A.Experimental Design plays an important role on establishing an interface between Applied Mathematics and statistical applications in several fields, like Agriculture, Industry, Genetics,Biology and Education Sciences. The goal of any Experimental Design is to obtain the maximum amount of information for a given experimental effort, to allow comparisons between varieties and to control for sources of random variability. Randomized block designs are used to control for these sources. A Balanced Incomplete Block Design (BIB Design) is a randomized block design with number of varieties greater than the block size and with all pairs of varieties occurring equally often along the blocks. The Fisher related information of a balanced block design will remain invariant whether or not the design has repeated blocks. This fact can be used theoretically to build a large number of non-isomorphic designs for the same set of design parameters, which could be used for many different purposes both in experimentations and surveys from finite populations. The original and most important method on the construction of BIB Designs with repeated blocks (BIBDR) is due to Hedayat and Li (1979): the trade-off method. Since then, many authors and researchers have been paying particular attention to the construction of BIBDR, but still some unsolved problems remain. This issue will be briefly reviewed and new results on the existence and construction of BIBDR, as well as several unsolved problems for further research will be presented.
- Book of abstracts : ISBIS 2016 : meeting on statistics in business and industryPublication . Oliveira, Amilcar; Mahmoudvand, Rahim; Ravishankar, Nalini; Banks, David; Oliveira, Teresa A.This Book includes the abstracts of the talks presented at the 2016 International Symposium on Business and Industrial Statistics, held at Barcelona, June 8-10, 2016, hosted at the Universitat Politècnica de Catalunya - Barcelona TECH, by the Department of Statistics and Operations Research. The location of the meeting was at ETSEIB Building (Escola Tecnica Superior d'Enginyeria Industrial) at Avda Diagonal 647. The meeting organizers celebrated the continued success of ISBIS and ENBIS society, and the meeting draw together the international community of statisticians, both academics and industry professionals, who share the goal of making statistics the foundation for decision making in business and related applications. The Scientific Program Committee was constituted by: David Banks, Duke University Amílcar Oliveira, DCeT - Universidade Aberta and CEAUL Teresa A. Oliveira, DCeT - Universidade Aberta and CEAUL Nalini Ravishankar, University of Connecticut Xavier Tort Martorell, Universitat Politécnica de Catalunya, Barcelona TECH Martina Vandebroek, KU Leuven Vincenzo Esposito Vinzi, ESSEC Business School