CODAMAT: a modern analogue techinque for compositional data

The quantitative estimation of Sea Surface Temperatures from fossils assemblages is a fundamental issue in palaeoclimatic and paleooceanographic investigations. The Modern Analogue Technique, a widely adopted method based on direct comparison of fossil assemblages with modern coretop samples, was revised with the aim of conforming it to compositional data analysis. The new CODAMAT method was developed by adopting the Aitchison metric as distance measure. Modern coretop datasets are characterised by a large amount of zeros. The zero replacement was carried out by adopting a Bayesian approach to the zero replacement, based on a posterior estimation of the parameter of the multinomial distribution. The number of modern analogues from which reconstructing the SST was determined by means of a multiple approach by considering the Proxies correlation matrix, Standardized Residual Sum of Squares and Mean Squared Distance. This new CODAMAT method was applied to the planktonic foraminiferal assemblages of a core recovered in the Tyrrhenian Sea. Kew words: Modern analogues, Aitchison distance, Proxies correlation matrix, Standardized Residual Sum of Squares

Comparing methods for dimensionality reduction when data are density functions

Functional Data Analysis (FDA) deals with samples where a whole function is observed for each individual. A particular case of FDA is when the observed functions are density functions, that are also an example of infinite dimensional compositional data. In this work we compare several methods for dimensionality reduction for this particular type of data: functional principal components analysis (PCA) with or without a previous data transformation and multidimensional scaling (MDS) for diferent inter-densities distances, one of them taking into account the compositional nature of density functions. The difeerent methods are applied to both artificial and real data (households income distributions)

Revisiting the compositional data. Some fundamental questions and new prospects in Archaeometry and Archaeology

In this paper we examine the problem of compositional data from a different starting point. Chemical compositional data, as used in provenance studies on archaeological materials, will be approached from the measurement theory. The results will show, in a very intuitive way that chemical data can only be treated by using the approach developed for compositional data. It will be shown that compositional data analysis is a particular case in projective geometry, when the projective coordinates are in the positive orthant, and they have the properties of logarithmic interval metrics. Moreover, it will be shown that this approach can be extended to a very large number of applications, including shape analysis. This will be exemplified with a case study in architecture of Early Christian churches dated back to the 5th-7th centuries AD

COMP6049 Quantitative analysis

notes for class discussion and exercise

Analysing Qualitative Data

Slides and Handouts for class introducing some of the concepts associated with the analysis of qualitative data

Capacidades dinámicas que influyen en la operación de la Red de Turismo de La Candelaria

El desarrollo de la presente investigación, centra su atención en las capacidades dinámicas que influyen en la operación de la Red de Turismo de La Candelaria de Bogotá. Para este fin, se realizó una encuesta a 100 directivos o dueños de las empresas que conforman dicha red, y que es una muestra significativa para los propósitos de la investigación, puesto que permite describir a nivel de la empresa y a nivel de la red, la influencia de las capacidades dinámicas de absorción, adaptación e innovación. Como resultados, se obtuvieron que al nivel de empresas las tres capacidades dinámicas influyen en la operación de la misma, encontrándose una mayor relación entre las capacidades de “Innovación – Adaptación"; a nivel de red empresarial ocurre lo contrario, puesto que la relación de las capacidades dinámicas de “Innovación – Adaptación” es nula, mientras que las relaciones entre “Absorción – Innovación” y “Absorción – Adaptación” poseen una alta relación para la operación de la red. Lo anterior, se deriva del análisis realizado de los datos tabulados de la encuesta aplicada a las empresas de la red de turismo, con los estudios empíricos hallados que proponen escalas de medición para las capacidades dinámicas de absorción, adaptación e innovación, y el marco teórico elaborado como soporte para la presente investigación.

Eye tracking data representation and visualization : on information and communication studies at CETAC.MEDIA

Eye tracking has become a preponderant technique in the evaluation of user interaction and behaviour with study objects in defined contexts. Common eye tracking related data representation techniques offer valuable input regarding user interaction and eye gaze behaviour, namely through fixations and saccades measurement. However, these and other techniques may be insufficient for the representation of acquired data in specific studies, namely because of the complexity of the study object being analysed. This paper intends to contribute with a summary of data representation and information visualization techniques used in data analysis within different contexts (advertising, websites, television news and video games). Additionally, several methodological approaches are presented in this paper, which resulted from several studies developed and under development at CETAC.MEDIA - Communication Sciences and Technologies Research Centre. In the studies described, traditional data representation techniques were insufficient. As a result, new approaches were necessary and therefore, new forms of representing data, based on common techniques were developed with the objective of improving communication and information strategies. In each of these studies, a brief summary of the contribution to their respective area will be presented, as well as the data representation techniques used and some of the acquired results.

Formação continuada: seus impactos na prática docente: um olhar sobre o programa pró-letramento

RESUMO: A preocupação central desta pesquisa foi compreendermos qual o impacto da formação continuada Pró-Letramento na prática pedagógica do professor a partir das necessidades e desafios do cotidiano escolar. Buscamos conhecer o conceito que os sujeitos da pesquisa têm sobre formação continuada, abordando a mesma como elemento da prática docente, comparamos o cotidiano de sala de aula de professores que passaram pela formação Pró-Letramento com os que não tiveram acesso a essa formação. Com respeito à formação continuada a percebemos como um processo dinâmico, reflexivo, que combina uma variedade de possibilidades e modalidades de aprendizagens, em que o professor vai adequando a sua formação às exigências sociais, culturais, educacionais. A formação continuada se dá, por meio da reflexão sobre a própria prática profissional no processo de ação-reflexão-ação, adquirindo significado na medida em que desenvolve e promove os diversos saberes docentes. A pesquisa foi conduzida com 90 professores do Ensino Fundamental – Anos Iniciais -, com oito coordenadoras que acompanham pedagogicamente os professores sujeitos dessa pesquisa e a observação em sala de aula. Procedeu-se à aplicação de um questionário validado e adaptado aos professores e uma entrevista aos coordenadores. A análise dos dados quantitativos foi realizada por meio do programa SPSS; enquanto a análise dos dados qualitativos foi orientada pela análise de discurso. A pesquisa aponta para algumas conclusões no que se refere a importância da Formação Continuada Pró-Letramento, tendo em vista a mesma possibilitar mudanças na prática pedagógica e colaborara para formação de um professor reflexivo, ao mesmo tempo que abre espaço para novos questionamentos e novos estudos.ABSTRACT: The central concern of this research was to understand the impact of the continuing education pro-literacy teaching practice from the teacher‘s needs and challenges of every day school life. We tried to know the concept that the subjects have on continuing education, addressing it as part of teaching practice, we compared the daily classroom teachers who have gone through training with Pro-Literacy did not access to such training. With respect to continuing education perceive it as a dynamic, reflective, which combines a variety of possibilities and modalities oF learning, the teacher will tailoring the training requirements to social, cultural, educational. The continuing education takes place, through reflection on own practice in the process of action-reflection-action, acquiring significance in that it develops and promotes the various teacher‘s knowledge. The research was conducted with 90 elementary school teacher‘s – Early Years – with eight coordinators accompanying teacher‘s pedagogically subject of research and observation in the classroom. Proceeded to the application of a validated questionnaire and adapted to an interview with the teachers and coordinators. The quantitative data analysis was performed using SPSS, while the analysis of qualitative data was guided by discourse analysis. The research points to some conclusions regarding the importance of Continuing Education Pro- Literacy in order to enable the same changes in teaching practice and collaborated to form a reflective teacher at the same time it makes room for new questions and new studies.

A Prática Pedagógica da Educação Física Escolar no Ensino Fundamental da Rede Pública da Cidade de Mossoró/RN

Esta investigação se propôs a compreender de que forma a prática pedagógica dos professores de Educação Física das escolas municipais de Mossoró/RN tem contribuído para promover o interesse dos alunos a respeito desta disciplina. A partir desse objetivo geral, especificamente procuramos levantar informações sobre a forma que as aulas de Educação Física são aplicadas nas escolas públicas da rede municipal da cidade de Mossoró-RN, identificamos a percepção dos professores a respeito do ensino da Educação Física nas escolas e comparamos com a análise dos alunos a respeito da prática pedagógica dos professores e como esta influencia a visão que estes têm acerca Educação Física. Metodologicamente, demonstramos a caracterização da pesquisa, que possui uma natureza qualitativa e quantitativa, definimos os sujeitos que foram 04 professores e 259 alunos do Ensino Fundamental e o lócus da investigação que foram 04 escolas da rede municipal de ensino da cidade de Mossoró-RN. Descrevemos também os instrumentos de coleta de dados, entrevistas realizadas com os professores e um questionário aplicado aos alunos e os procedimentos de análise dos dados. Nas considerações finais, apontamos que apesar de haver uma consciência por parte dos alunos que a Educação Física escolar ainda está muito enraizada a funções tradicionalmente ligadas a essa área do conhecimento, tais como trabalho da parte física dos alunos, contribuir para a saúde e preparar atletas para as escolas. Os resultados apontam ainda para uma clara falta de estrutura física das escolas para a prática da Educação Física nas escolas municipais de Mossoró/RN. Esses alunos consideram, a partir da prática pedagógica dos seus professores, que as aulas de Educação Física são empolgantes, dinâmicas e se constituem espaços que contribuem para a interação entre eles e o ensino de valores, que por sua vez produzem nesses alunos um constante interesse na participação dessas aulas.

Sharing and visualizing environmental data using Virtual Globes

Virtual globe technology holds many exciting possibilities for environmental science. These easy-to-use, intuitive systems provide means for simultaneously visualizing four-dimensional environmental data from many different sources, enabling the generation of new hypotheses and driving greater understanding of the Earth system. Through the use of simple markup languages, scientists can publish and consume data in interoperable formats without the need for technical assistance. In this paper we give, with examples from our own work, a number of scientific uses for virtual globes, demonstrating their particular advantages. We explain how we have used Web Services to connect virtual globes with diverse data sources and enable more sophisticated usage such as data analysis and collaborative visualization. We also discuss the current limitations of the technology, with particular regard to the visualization of subsurface data and vertical sections.

An extension of an over-dispersion test for count data

While over-dispersion in capture–recapture studies is well known to lead to poor estimation of population size, current diagnostic tools to detect the presence of heterogeneity have not been specifically developed for capture–recapture studies. To address this, a simple and efficient method of testing for over-dispersion in zero-truncated count data is developed and evaluated. The proposed method generalizes an over-dispersion test previously suggested for un-truncated count data and may also be used for testing residual over-dispersion in zero-inflation data. Simulations suggest that the asymptotic distribution of the test statistic is standard normal and that this approximation is also reasonable for small sample sizes. The method is also shown to be more efficient than an existing test for over-dispersion adapted for the capture–recapture setting. Studies with zero-truncated and zero-inflated count data are used to illustrate the test procedures.

Time patterns in UK demand for alcohol and tobacco: an application of the EM algorithm

Capturing the pattern of structural change is a relevant task in applied demand analysis, as consumer preferences may vary significantly over time. Filtering and smoothing techniques have recently played an increasingly relevant role. A dynamic Almost Ideal Demand System with random walk parameters is estimated in order to detect modifications in consumer habits and preferences, as well as changes in the behavioural response to prices and income. Systemwise estimation, consistent with the underlying constraints from economic theory, is achieved through the EM algorithm. The proposed model is applied to UK aggregate consumption of alcohol and tobacco, using quarterly data from 1963 to 2003. Increased alcohol consumption is explained by a preference shift, addictive behaviour and a lower price elasticity. The dynamic and time-varying specification is consistent with the theoretical requirements imposed at each sample point. (c) 2005 Elsevier B.V. All rights reserved.

Bayesian analysis of an inverse Gaussian correlated frailty model

In survival analysis frailty is often used to model heterogeneity between individuals or correlation within clusters. Typically frailty is taken to be a continuous random effect, yielding a continuous mixture distribution for survival times. A Bayesian analysis of a correlated frailty model is discussed in the context of inverse Gaussian frailty. An MCMC approach is adopted and the deviance information criterion is used to compare models. As an illustration of the approach a bivariate data set of corneal graft survival times is analysed. (C) 2006 Elsevier B.V. All rights reserved.

Understanding the indoor environment through mining sensory data - A case study

A wireless sensor network (WSN) is a group of sensors linked by wireless medium to perform distributed sensing tasks. WSNs have attracted a wide interest from academia and industry alike due to their diversity of applications, including home automation, smart environment, and emergency services, in various buildings. The primary goal of a WSN is to collect data sensed by sensors. These data are characteristic of being heavily noisy, exhibiting temporal and spatial correlation. In order to extract useful information from such data, as this paper will demonstrate, people need to utilise various techniques to analyse the data. Data mining is a process in which a wide spectrum of data analysis methods is used. It is applied in the paper to analyse data collected from WSNs monitoring an indoor environment in a building. A case study is given to demonstrate how data mining can be used to optimise the use of the office space in a building.