Contrastes ortogonais: definições e conceitos

A técnica de contrastes ortogonais com um grau de liberdade é simples e bastante eficiente na análise de dados experimentais, como por exemplo, na obtenção de efeitos principais, de efeito de interação e de efeitos aninhados, nas comparações entre grupos de médias e na obtenção dos resíduos específicos. Além disso, sua aplicação tem revelado ser uma forma alternativa para análise de dados obtidos de um experimento que não segue uma estrutura definida. Com o objetivo de justificar a sua aplicação, foi realizada uma revisão sobre as definições e os conceitos envolvendo contrastes.The single degree of freedom of orthogonal contrasts is a useful technique for the analysis of experimental data and helpful in obtaining estimates of main, nested and interaction effects, for mean comparisons between groups of data and in obtaining specific residuals. Furthermore, the application of orthogonal contrasts is an alternative way of doing statistical analysis on data from non-conventional experiments, whithout a definite structure. To justify its application, an extensive review is made on the definitions and concepts involving contrasts

Resíduo específico: aplicação de contrastes ortogonais na presença da heterocedasticidade

Ao realizar-se a análise da variância de um conjunto de dados, pressupõe-se que o critério de homocedasticidade (homogeneidade de variâncias entre tratamentos), associada ao modelo matemático adotado, seja satisfeito. Esta verificação se faz necessária para a correta aplicação dos testes de significância. Quando não é satisfeita, em certos casos, compromete a normalidade dos erros. Uma alternativa para contornar essa deficiência é a aplicação do resíduo específico, que consiste em decompor a soma de quadrados do resíduo em componentes, correspondentes aos contrastes ortogonais de interesse, apropriados para testar cada contraste ortogonal entre médias de tratamentos. A decomposição da soma de quadrados do resíduo é um procedimento pouco utilizado, mas é útil para melhor compreensão da natureza do quadrado médio residual e garantir a validade dos testes aplicados. Nessa revisão avaliou-se a aplicação dos resíduos específicos como alternativa válida e adequada, na análise de dados obtidos de experimentos que seguem a estrutura dos delineamentos inteiramente casualizados e em blocos casualizados, na presença da heterocedasticidade.When experimental data are submitted to analysis of variance, the assumption of data homoscedasticity (variance homogeneity among treatments), associated to the adopted mathematical model must be satisfied. This verification is necessary to ensure the correct test for the analysis. In some cases, when data homoscedascity is not observed, errors may invalidate the analysis. An alternative to overcome this difficulty is the application of the specific residue analysis, which consists of the decomposition of the residual sum of squares in its components, in order to adequately test the correspondent orthogonal contrasts of interest between treatment means. Although the decomposition of the residual sum of squares is a seldom used procedure, it is useful for a better understanding of the residual mean square nature and to validate the tests to be applied. The objective of this review is to illustrate the specific residue application as a valid and adequate alternative to analyze data from experiments following completely randomized and randomized complete block designs in the presence of heteroscedasticity

A hierarchical Bayesian non-asymptotic extreme value model for spatial data

Spatial maps of extreme precipitation are crucial in flood protection. With the aim of producing maps of precipitation return levels, we propose a novel approach to model a collection of spatially distributed time series where the asymptotic assumption, typical of the traditional extreme value theory, is relaxed. We introduce a Bayesian hierarchical model that accounts for the possible underlying variability in the distribution of event magnitudes and occurrences, which are described through latent temporal and spatial processes. Spatial dependence is characterized by geographical covariates and effects not fully described by the covariates are captured by spatial structure in the hierarchies. The performance of the approach is illustrated through simulation studies and an application to daily rainfall extremes across North Carolina (USA). The results show that we significantly reduce the estimation uncertainty with respect to state of the art techniques

Modelling Constrained Dynamic Software Architecture with Attributed Graph Rewriting Systems

Dynamic software architectures are studied for handling adap- tation in distributed systems, coping with new requirements, new envi- ronments, and failures. Graph rewriting systems have shown their ap- propriateness to model such architectures, particularly while considering the consistency of theirs reconfigurations. They provide generic formal means to specify structural properties, but imply a poor description of specific issues like behavioural properties. This paper lifts this limita- tion by proposing a formal approach for integrating the consideration of constraints, non-trivial attributes, and their propagation within the framework of graph rewriting systems

Traductions et adaptations françaises de l’Elegia di madonna Fiammetta

L’ouvrage de Boccace qui a connu et connaît le plus grand nombre de traductions françaises est sans conteste le Décaméron. Est-ce à dire que cette curiosité presque exclusive n’a laissé, en France, aucune place pour d’autres œuvres du conteur florentin ? Il suffit de parcourir les éditions lues au xve siècle et au siècle suivant pour apporter une réponse plus nuancée. C’est aux traductions et adaptations françaises de l’Elegia di madonna Fiammetta au xvie siècle que nous consacrerons ici la p..

La gestion des ressources pour des infrastructures vertes par la reconfiguration

Cette HDR présente des travaux dans le contexte des systèmes informatiques à grande échelle pouvant être des grilles de calcul ou le cloud computing. Partant de deux constats : la consommation énergétique de ces systèmes est trop importante et ces systèmes sont de plus en complexes, ce mémoire se propose de répondre à la problématique suivante : comment gérer de manière optimale les ressources afin d'obtenir des infrastructures matérielles et logicielles "vertes" c'est à dire efficaces en énergie ? Ces travaux proposent trois axes de recherche : le premier en considérant le système complet et les leviers verts associés, le deuxième en étudiant des politiques d'allocation de ressources avec contraintes d'énergie et de chaleur, le troisième en étudiant des reconfigurations autonomiques d'applications. Pour finir, une description d'un centre de décision autonome pour des infrastructures vertes est proposée

Correctness by Construction and Style Preserving Reconfigurations of Distributed Systems.

In distributed systems and dynamic environments, software architectures may evolve. A crucial issue when conducting system evolutions is to maintain the system in a consistent and functional state. Based on formal proofs in design-time, correctness by construction has recently emerged to efficiently guarantee system coherency. This article proposes a new method for the construction and specification of correct by construction system reconfigurations. Such transformations are characterized by graph rewriting rules that necessarily preserve the coherency of a system. We firstly propose operators on graph transformations and show that they conserve their correctness. Given a system specified by a graph grammar, these operators then serve to construct and characterize a set of correct transformations. We show in particular that any correct configuration can be reached starting from any other one without inconsistent intermediate step, using these transformations only

Sob/sobre notas-desenhos de escuta

ResumoO presente texto apresenta investigações em torno de experiências de silêncio, bem como acerca de propostas de escrita, leitura e escuta que pendem segundo ângulos de suspensão (usos de uma palavra pênsil) e de processos que envolvem uma escuta porosa. Tais investigações movem o processo da publicação sonora assonâncias de silêncios [coleção] (2007-2010), que articula relações entre componentes sonoros e escritos, propondo situações de leitura e escuta de silêncios. Mas, se a maquinaria de sentido é algo difícil de interromper e suspender, como propor silêncios em/para outras escutas, em publicações sonoras? Talvez, pela diminuição da audição, trabalhando com audibilidades precárias? Ou tentando pausar o que se ouve no que se escuta? Partindo de outra premissa-interrogação: como ouvir, escutar e escrever-desenhar silêncios?AbstractThis paper presents some researches about silence experiences as well as about writing, reading and listening proposals, that move according to suspension angles (uses of a suspended word) and processes involving a porous listening. Such investigations move the process of sound publication assonâncias de silêncios [coleção] (2007-2010), that articulate relations between sound and written components by proposing situations of reading and listening silences. However, if the sense machinery is difficult to stop and suspend, how can one propose silences in/to other listening, in sound publications? Perhaps, by decreasing hearing, working with precarious audible facts? Or trying to pause what you hear in what you listen? Starting from another premise-question: how to hear, listen and write-draw silences?