The bounded Fatou components for certain quadratic polynomials are attached to each other at the boundary and form chain-like structures called ``bubble rays". In the context of mating quadratic polynomials, these bubble rays can serve as a replacement for external rays. The main objective of this thesis is to apply this idea to the mating of starlike quadratics.

The bounded Fatou components for certain quadratic polynomials are attached to each other at the boundary and form chain-like structures called ``bubble rays". In the context of mating quadratic polynomials, these bubble rays can serve as a replacement for external rays. The main objective of this thesis is to apply this idea to the mating of starlike quadratics.

This thesis identifies and analyzes successful movement strategies for the completion of a complex dynamic task. In the past it has been shown that movement strategies correlate well to performance for simple tasks. Therefore, in this thesis I was motivated to find out if motion based metrics correlated well to performance for more complicated motor tasks. First, the Nintendo Wiimote was verified as a suitable gaming interface enabling gross human motion capture through experimental comparisons with other gaming interfaces and precision sensors. Then, a complex motor task was rendered in an open-source gaming environment. This environment enabled the design of a rhythmic task that could be controlled with the Wiimote while data were simultaneously recorded for later analysis. For the task, success and failure could be explained by high correlation between two motion based performance metrics, mean absolute jerk (MAJ) and average frequency (AVF) per trial. A logistic regression analysis revealed that each subject had a range of MAJ and AVF values for being successful, outside of which they were unsuccessful. Therefore, this thesis identifies motion based performance metrics for a novel motor control task that is significantly difficult to master and the techniques used to identify successful movement strategies can be used for predicting success for other such complex dynamic tasks.

Nous montrons un résultat du type Closing Lemma pour les mesures non uniformément hyperboliques associées à des applications méromorphes. Nous prouvons aussi qu'il est possible d'approximer la dynamique de telles mesures par des codages du type Bernoulli. / We prove a Closing Lemma for nonuniformly hyperbolic measures of meromor-phic maps. We prove also a theorem of approxiamtion of the dynamics of such measures by Bernoulli coding maps.

The ever-increasing complexity of software systems makes them hard to comprehend, predict and tune due to emergent properties and non-deterministic behaviour. Complexity arises from the size of software systems and the wide variety of possible operating environments: the increasing choice of platforms and communication policies leads to ever more complex performance characteristics. In addition, software systems exhibit different behaviour under different workloads. Many software systems are designed to be configurable so that policies (e.g. communication, concurrency and recovery strategies) can be chosen to meet the needs of various stakeholders. For complex software systems it can be difficult to accurately predict the effects of a change and to know which configuration is most appropriate. This thesis demonstrates that it is useful to run automated experiments that measure a selection of system configurations. Experiments can find configurations that meet the stakeholders' needs, find interesting behavioural characteristics, and help produce predictive models of the system's behaviour. The design and use of ACT (Automated Configuration Tool) for running such experiments is described, in combination a number of search strategies for deciding on the configurations to measure. Design Of Experiments (DOE) is discussed, with emphasis on Taguchi Methods. These statistical methods have been used extensively in manufacturing, but have not previously been used for configuring software systems. The novel contribution here is an industrial case study, applying the combination of ACT and Taguchi Methods to DC-Directory, a product from Data Connection Ltd (DCL). The case study investigated the applicability of Taguchi Methods for configuring complex software systems. Taguchi Methods were found to be useful for modelling and configuring DC-Directory, making them a valuable addition to the techniques available to system administrators and developers.

Onde há luz suficiente ,os estômatos, pequenos poros localizados na superfície das folhas, com abertura regulável, tendem a abrir . Isto permite a absorção de C02 (e, portanto, a fotossíntese) , e a evaporação de água, que não pode, porém, ser excessiva. As plantas conseguem ajustar a sua abertura dos estômatos, otimizando a absorção de C02 e adequando-se, ao mesmo tempo, à disponibilidade de água no ambiente. Recentemente, inúmeras experiências mostraram que, ao contrário do que se supunha, a abertura de um estômato parece depender da interação deste com seus estômatos vizinhos. Sob estresse hídrico, o movimento de abrir e fechar, dos estômatos de uma região da folha, freqüentemente se sincroniza, formando padrões espaço-temporais persistentes. Este trabalho teve como objetivo o estudo da dinâmica desses padrões. Reproduzimos, num primeiro momento deste estudo, um modelo proposto por Haefner e colaboradores, para entender melhor o problema. Este modelo , no entanto, demonstrou ser ineficiente sob vários aspectos, ao contrário do que observam os autores. Novos modelos foram então propostos, com resultaados mais próximos aos observados nos experimentosque apresentam melhor concordância com os experimentos. Em particular, destacamos o Modelo de Veias Aleatórias com Histerese, que utiliza a hipótese da existência de um retardo e uma histerese no mecanismo de abertura e fechamento dos estômatos, com resultados que reproduzem a diversidade de comportamento da dinâmica estomática observada experimentalmente. / When there is enough light, stomata - variable aperture pores distributed on plant´s leaves - tend to open. This mechanism allows the absorption of C02 (and so the reaction of photosynthesis) as well as the evaporation of water. The plant can adjust its stomatal aperture over time, in order to maximize C02 uptake with an water loss compatible with environmental conditions. Recently, many experiments have shown that the aperture of a single stomata depends on its interaction with the neighbors in an emergent complex behavior. Under water stress the opening and closing of stomata aperture often becomes synchronized in spatially extended patches, with a rich dynamical behavior. In this work we have studied this phenomena. We first reproduce a model proposed by Haefner and collaborators, in an attempt to better understand this phenomena. The model, however, has been unable to generate patches or an oscillatory behavior in the steady state, as claimed by th authors. We proposed then new models, that show better agreement with experiments. In a particular, the model called by us Randon Vein Model with Hysteresis was able to reproduce most of the behaviors observed in real leaves, including the formation of patches and an non-regular oscillations in the steady state.

<p>This thesis focuses on the development of ABC methods for statistical modeling in complex dynamic systems. Motivated by real applications in biology, I propose computational strategies for Bayesian inference in contexts where standard Monte Carlo methods cannot be directly applied due to the high complexity of the dynamic model and/or data limitations.</p><p> Chapter 2 focuses on stochastic bionetwork models applied to data generated from the marginal distribution of a few network nodes at snapshots in time. I present a Bayesian computational strategy, coupled with an approach to summarizing and numerically characterizing biological phenotypes that are represented in terms of the resulting sample distributions of cellular markers. ABC and mixture modeling are used to define the approach to linking mechanistic mathematical models of network dynamics to snapshot data, using a toggle switch example integrating simulated and real data as context. </p><p> Chapter 3 focuses on the application of the methodology presented in Chapter 2 to the Myc/Rb/E2F network. This network involves a relatively high number of parameters and stochastic equations in the model specification and, thus, is substantially more complex than the toggle switch example. The analysis of the Myc/Rb/E2F network is performed with simulated and real data. I demonstrate that the proposed method can indicate which parameters can be learned about using the marginal data. </p><p> In Chapter 4, I present an ABC SMC method that uses data-based adaptive weights. This easily implemented and computationally trivial extension of ABC SMC can substantially improve acceptance rates. This is demonstrated through a series of examples with simulated and real data, including the toggle switch example. Theoretical justification is also provided to explain why this method is expected to improve the effectiveness of ABC SMC.</p><p> In Chapter 5, I present an integrated Bayesian computational strategy for fitting complex dynamic models to sparse time-series data. This is applied to experimental data from an immunization response study with Indian Rhesus macaques. The computational strategy consists of two stages: first, MCMC is implemented based on simplified sampling steps, and then, the resulting approximate output is used to generate a proposal distribution for the parameters that results in an efficient ABC procedure. The incorporation of ABC as a correction tool improves the model fit, as is demonstrated through predictive posterior analysis on the data sets of the study.</p><p> Chapter 6 presents additional discussion and comments on potential future research directions.</p> / Dissertation

Onde há luz suficiente ,os estômatos, pequenos poros localizados na superfície das folhas, com abertura regulável, tendem a abrir . Isto permite a absorção de C02 (e, portanto, a fotossíntese) , e a evaporação de água, que não pode, porém, ser excessiva. As plantas conseguem ajustar a sua abertura dos estômatos, otimizando a absorção de C02 e adequando-se, ao mesmo tempo, à disponibilidade de água no ambiente. Recentemente, inúmeras experiências mostraram que, ao contrário do que se supunha, a abertura de um estômato parece depender da interação deste com seus estômatos vizinhos. Sob estresse hídrico, o movimento de abrir e fechar, dos estômatos de uma região da folha, freqüentemente se sincroniza, formando padrões espaço-temporais persistentes. Este trabalho teve como objetivo o estudo da dinâmica desses padrões. Reproduzimos, num primeiro momento deste estudo, um modelo proposto por Haefner e colaboradores, para entender melhor o problema. Este modelo , no entanto, demonstrou ser ineficiente sob vários aspectos, ao contrário do que observam os autores. Novos modelos foram então propostos, com resultaados mais próximos aos observados nos experimentosque apresentam melhor concordância com os experimentos. Em particular, destacamos o Modelo de Veias Aleatórias com Histerese, que utiliza a hipótese da existência de um retardo e uma histerese no mecanismo de abertura e fechamento dos estômatos, com resultados que reproduzem a diversidade de comportamento da dinâmica estomática observada experimentalmente. / When there is enough light, stomata - variable aperture pores distributed on plant´s leaves - tend to open. This mechanism allows the absorption of C02 (and so the reaction of photosynthesis) as well as the evaporation of water. The plant can adjust its stomatal aperture over time, in order to maximize C02 uptake with an water loss compatible with environmental conditions. Recently, many experiments have shown that the aperture of a single stomata depends on its interaction with the neighbors in an emergent complex behavior. Under water stress the opening and closing of stomata aperture often becomes synchronized in spatially extended patches, with a rich dynamical behavior. In this work we have studied this phenomena. We first reproduce a model proposed by Haefner and collaborators, in an attempt to better understand this phenomena. The model, however, has been unable to generate patches or an oscillatory behavior in the steady state, as claimed by th authors. We proposed then new models, that show better agreement with experiments. In a particular, the model called by us Randon Vein Model with Hysteresis was able to reproduce most of the behaviors observed in real leaves, including the formation of patches and an non-regular oscillations in the steady state.

De nombreuses applications de la vision par ordinateur requièrent la détection, la localisation et le suivi de régions ou d’objets d’intérêt dans une image ou une séquence d’images. De nombreux modèles d’attention visuelle, inspirés de la vision humaine, qui détectent de manière automatique les régions d’intérêt dans une image ou une vidéo, ont récemment été développés et utilisés avec succès dans différentes applications. Néanmoins, la plupart des approches existantes sont limitées à l’analyse de scènes statiques et très peu de méthodes exploitent la nature temporelle des séquences d’images.L'objectif principal de ce travail de thèse est donc l'étude de modèles d'attention visuelle pour l'analyse de scènes dynamiques complexes. Une carte de saliance est habituellement obtenue par la fusion d'une carte statitque (saliance spatiale dans une image) d'une part, et d'une carte dynamique (salience temporelle entre une série d'image) d'autre part. Dans notre travail, nous modélisons les changements dynamiques par un opérateur de texture LBP-TOP (Local Binary Patterns) et nous utilisons l'information couleur pour l'aspect spatial.Les deux cartes de saliances sont calculées en utilisant une formulation discriminante inspirée du système visuel humain, et fuionnées de manière appropriée en une carte de saliance spatio-temporelle.De nombreuses expériences avec des bases de données publiques, montrent que notre approche obteint des résulats meilleurs ou comparables avec les approches de la littérature. / Visual saliency is an important research topic in the field of computer vision due to its numerouspossible applications. It helps to focus on regions of interest instead of processingthe whole image or video data. Detecting visual saliency in still images has been widelyaddressed in literature with several formulations. However, visual saliency detection invideos has attracted little attention, and is a more challenging task due to additional temporalinformation. Indeed, a video contains strong spatio-temporal correlation betweenthe regions of consecutive frames, and, furthermore, motion of foreground objects dramaticallychanges the importance of the objects in a scene. The main objective of thethesis is to develop a spatio-temporal saliency method that works well for complex dynamicscenes.A spatio-temporal saliency map is usually obtained by the fusion of a static saliency mapand a dynamic saliency map. In our work, we model the dynamic textures in a dynamicscene with Local Binary Patterns (LBP-TOP) to compute the dynamic saliency map, andwe use color features to compute the static saliency map. Both saliency maps are computedusing a bio-inspired mechanism of Human Visual System (HVS) with a discriminantformulation known as center surround saliency, and are fused in a proper way.The proposed models have been extensively evaluated with diverse publicly availabledatasets which contain several videos of dynamic scenes. The evaluation is performed intwo parts. First, the method in locating interesting foreground objects in complex scene.Secondly, we evaluate our model on the task of predicting human observers fixations.The proposed method is also compared against state-of-the art methods, and the resultsshow that the proposed approach achieves competitive results.In this thesis we also evaluate the performance of different fusion techniques, because fusionplays a critical role in the accuracy of the spatio-temporal saliency map. We evaluatethe performances of different fusion techniques on a large and diverse complex datasetand the results show that a fusion method must be selected depending on the characteristics,in terms of color and motion contrasts, of a sequence. Overall, fusion techniqueswhich take the best of each saliency map (static and dynamic) in the final spatio-temporalmap achieve best results.

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