ABSTRACT Charles W. Chesnutt captures the essence of the Post Civil War period and gives examples of the assimilation process for African Americans into dominant white culture. In doing so, he shows the resistance of the dominant culture as well as the resilience of the African American culture. It is his belief that through literature he could encourage moral reform and eliminate racial discrimination. As an African American author who could pass for white, he is able to share his own experiences and to develop black characters who are ambitious and intelligent. As a result, he leaves behind a legacy of great works that are both informative and entertaining.

This work is a study of a community of Croatian immigrants to Southeast Louisiana in the twentieth century. Drawn from a multidisciplinary approach that included spatial analysis of settlement patterns, quantitative analysis of seafood industry data, the records of voluntary associations, and guided by the oral histories of men and women of Croatia who immigrated to Louisiana, this work reveals a community that has managed to maintain close ties despite its distribution both in urban New Orleans and rural coastal Louisiana through links created by and supportive of the state’s seafood and restaurant industries. The study points out how the custom of returning to Croatia for marriage and the retention of property in Croatia helped the group maintain links with its national and cultural origins in ways not always seen with other ethnic groups in America, pointing out the range of the immigrant experience in the United States.

This work employs statistical and Bayesian techniques to analyze mathematical forward models with several sources of uncertainty. The forward models usually arise from phenomenological and physical phenomena and are expressed through regression-based models or partial differential equations (PDEs) associated with uncertain parameters and input data. One of the critical challenges in real-world applications is to quantify uncertainties of the unknown parameters using observations. To this purpose, methods based on the likelihood function, and Bayesian techniques constitute the two main statistical inferential approaches considered here. Two problems are studied in this thesis. The first problem is the prediction of fatigue life of metallic specimens. The second part is related to inverse problems in linear PDEs. Both problems require the inference of unknown parameters given certain measurements. We first estimate the parameters by means of the maximum likelihood approach. Next, we seek a more comprehensive Bayesian inference using analytical asymptotic approximations or computational techniques. In the fatigue life prediction, there are several plausible probabilistic stress-lifetime (S-N) models. These models are calibrated given uniaxial fatigue experiments. To generate accurate fatigue life predictions, competing S-N models are ranked according to several classical information-based measures. A different set of predictive information criteria is then used to compare the candidate Bayesian models. Moreover, we propose a spatial stochastic model to generalize S-N models to fatigue crack initiation in general geometries. The model is based on a spatial Poisson process with an intensity function that combines the S-N curves with an averaged effective stress that is computed from the solution of the linear elasticity equations.

O presente trabalho tem como objetivo refletir sobre o processo de assimilação imposto às populações do território angolano dos anos de 1950 e 1960 presente na obra literária Kinaxixe, de Arnaldo Santos, publicada em 1965, em Portugal, e em 1981, no Brasil. A obra de nove contos retrata a tensa convivência dos negros, mestiços e brancos nos musseques e bairros que circundam a costa luandense no auge da maior migração de brancos portugueses ao território angolano. Por meio de leis como o então recente Estatuto do Indigenato, de 1954 e o Acto Colonial, de 1933 acirram-se as diferenças sociais. Esse plano jurídico foi baseado em teorias darwinistas do século XIX e lido de maneira hierarquizante e subjugadora, separando as populações do território angolano como não civilizados ou assimilados, e fazendo dos portugueses, em oposição, supostamente, civilizados, aptos a colonizar as populações do território baseado, por isso, na suposta superioridade cultural e social. / This present paper aims to study the assimilation process imposed on the populations of the Angolan territory in the 1950s and in the 1960s seen in the literary work Kinaxixe, by Arnaldo Santos, published in Lisbon, Portugal in 1965 and in Brazil, in 1981. The nine short stories reflect the tense coexistence among black people, mixed race people and white people in the musseques (slums) and neighborhoods that surround the coast of Luanda. At this time, the largest Portuguese migration to the African territory took place. Through some laws such as the Estatuto do Indigenato, from 1954 and the Acto Colonial, from 1933, the social differences were even more stimulated. These legal spheres were based on Darwinist theories from the 19th century read in a patriarchal repressive and classicist way separating the populations in non-civilized or assimilated making the Portuguese, on the other hand, supposedly, civilized. Therefore, according to these thoughts, the Portuguese were prepared to colonize the Angolan population through, also a supposed, cultural and social superiority.

Bayesian inference is commonly used to quantify and reduce modeling uncertainties in coastal ocean models by computing the posterior probability distribution function (pdf) of some uncertain quantities to be estimated conditioned on available observations. The posterior can be computed either directly, using a Markov Chain Monte Carlo (MCMC) approach, or by sequentially processing the data following a data assimilation (DA) approach. The advantage of data assimilation schemes over MCMC-type methods arises from the ability to algorithmically accommodate a large number of uncertain quantities without a significant increase in the computational requirements. However, only approximate estimates are generally obtained by this approach often due to restricted Gaussian prior and noise assumptions. This thesis aims to develop, implement and test novel efficient Bayesian inference techniques to quantify and reduce modeling and parameter uncertainties of coastal ocean models. Both state and parameter estimations will be addressed within the framework of a state of-the-art coastal ocean model, the Advanced Circulation (ADCIRC) model. The first part of the thesis proposes efficient Bayesian inference techniques for uncertainty quantification (UQ) and state-parameters estimation. Based on a realistic framework of observation system simulation experiments (OSSEs), an ensemble Kalman filter (EnKF) is first evaluated against a Polynomial Chaos (PC)-surrogate MCMC method under identical scenarios. After demonstrating the relevance of the EnKF for parameters estimation, an iterative EnKF is introduced and validated for the estimation of a spatially varying Manning’s n coefficients field. Karhunen-Lo`eve (KL) expansion is also tested for dimensionality reduction and conditioning of the parameter search space. To further enhance the performance of PC-MCMC for estimating spatially varying parameters, a coordinate transformation of a Gaussian process with parameterized prior covariance function is next incorporated into the Bayesian inference framework to account for the uncertainty in covariance model hyperparameters. The second part of the thesis focuses on the use of UQ and DA on adaptive mesh models. We developed new approaches combining EnKF and multiresolution analysis, and demonstrated significant reduction in the cost of data assimilation compared to the traditional EnKF implemented on a non-adaptive mesh.

Esta dissertação tem como objetivo principal a reconstrução conceitual e teórica dos estudos de imigração de Louis Wirth, sociólogo de origem alemã, naturalizado norte-americano, associado à tradição da Escola Sociológica de Chicago. A análise centrou-se em seus escritos de formação: Culture Conflict in the Immigrante Family (1925), sua dissertação de mestrado, e The Ghetto (1928), a publicação de sua tese de doutorado, complementados por alguns artigos. Os principais elementos reconstruídos foram, não necessariamente nessa ordem: a condição do imigrante de desorganização e reorganização pessoal e de grupo; a teoria da assimilação; os conflitos culturais e a delinquência entre a segunda geração de imigrantes; a psicologia social do imigrante e seus tipos sociais e de personalidade; a possibilidade de aplicação do conhecimento sociológico para intervenção na realidade social; e, o conceito de gueto, na interpretação do isolamento espacial, cultural e social. Esses elementos foram analisados não apenas nas formulações do autor, mas também pelas influências que sofreu de William I. Thomas, Robert E. Park e Ernest W. Burgess. Quanto ao conceito de gueto, especificamente, foi realizado também o exame de sua incorporação na sociologia e nos estudos raciais norte-americanos, posteriores ao autor, na reavaliação e crítica elaborada por Loïc Wacquant. / This thesis has as main purpose the conceptual and theoretical reconstruction of the studies of immigration from Louis Wirth, sociologist of German origin, naturalized American, associated with the tradition of the Chicago School of Sociology. The analysis focused on the author\'s formation writings: Culture Conflict in the Immigrant Familiy (1925), his master thesis, and The Ghetto (1928), the publication of his doctoral thesis, supplemented by some articles. The main reconstructed elements were, not necessarily in this order: the immigrant condition of individual and group disorganization and reorganization; the assimilation theory; cultural conflicts and delinquency in the second generation of immigrants; the social psychology of the immigrant and its social and personality types; the possibility of applying sociological knowledge to change social reality; and the concept of ghetto for the interpretation of spatial, cultural and social isolation. These elements were analyzed not only in the author\'s formulations but also in the influences that he had suffered from William I. Thomas, Robert E. Park and Ernest W. Burgess. Regarding the concept of ghetto, specifically, it was also examined its development in American sociology and racial studies, later to the author, in the review and critique elaborated by Loïc Wacquant.

Grannspråksförståelsen mellan danska och svenska har i flera undersökningar visat sig vara asymmetrisk vad hörförståelsen beträffar. En anledning till denna asymmetri förmodas vara ljudförändringar i danskan. Syftet med denna uppsats är att undersöka hur drag som försvagningar och assimilationer i danska språket påverkar svenskars uppfattning och förståelse av talad danska. Detta undersöks genom ett experiment, där jag testar svenska gymnasieelevers uppfattning och förståelse av åtta utvalda försvagningar och assimilationer. 40 personer deltog i experimentet varav materialet från sju personer sorterades bort. Slutsatsen är att sex av de undersökta dragen påverkar informanternas uppfattning av de undersökta orden negativt. Det var fler informanter som uppfattade de undersökta dragen korrekt, än det var som förstod orden. Detta tyder på att det är mer än just de undersökta dragen som påverkar informanternas uppfattning och förståelse av orden. Antalet testade ord för varje drag är dock för lågt för att säga något om hur de undersökta försvagningar och assimilationer påverkar svenskars uppfattning generellt.

Esta dissertação tem como objetivo principal a reconstrução conceitual e teórica dos estudos de imigração de Louis Wirth, sociólogo de origem alemã, naturalizado norte-americano, associado à tradição da Escola Sociológica de Chicago. A análise centrou-se em seus escritos de formação: Culture Conflict in the Immigrante Family (1925), sua dissertação de mestrado, e The Ghetto (1928), a publicação de sua tese de doutorado, complementados por alguns artigos. Os principais elementos reconstruídos foram, não necessariamente nessa ordem: a condição do imigrante de desorganização e reorganização pessoal e de grupo; a teoria da assimilação; os conflitos culturais e a delinquência entre a segunda geração de imigrantes; a psicologia social do imigrante e seus tipos sociais e de personalidade; a possibilidade de aplicação do conhecimento sociológico para intervenção na realidade social; e, o conceito de gueto, na interpretação do isolamento espacial, cultural e social. Esses elementos foram analisados não apenas nas formulações do autor, mas também pelas influências que sofreu de William I. Thomas, Robert E. Park e Ernest W. Burgess. Quanto ao conceito de gueto, especificamente, foi realizado também o exame de sua incorporação na sociologia e nos estudos raciais norte-americanos, posteriores ao autor, na reavaliação e crítica elaborada por Loïc Wacquant. / This thesis has as main purpose the conceptual and theoretical reconstruction of the studies of immigration from Louis Wirth, sociologist of German origin, naturalized American, associated with the tradition of the Chicago School of Sociology. The analysis focused on the author\'s formation writings: Culture Conflict in the Immigrant Familiy (1925), his master thesis, and The Ghetto (1928), the publication of his doctoral thesis, supplemented by some articles. The main reconstructed elements were, not necessarily in this order: the immigrant condition of individual and group disorganization and reorganization; the assimilation theory; cultural conflicts and delinquency in the second generation of immigrants; the social psychology of the immigrant and its social and personality types; the possibility of applying sociological knowledge to change social reality; and the concept of ghetto for the interpretation of spatial, cultural and social isolation. These elements were analyzed not only in the author\'s formulations but also in the influences that he had suffered from William I. Thomas, Robert E. Park and Ernest W. Burgess. Regarding the concept of ghetto, specifically, it was also examined its development in American sociology and racial studies, later to the author, in the review and critique elaborated by Loïc Wacquant.

This thesis presents a research work on the development of new methodology for near-real-time detection and localisation of pipe bursts in a Water Distribution System (WDS) at the District Meters Area (DMA) level. The methodology makes use of online hydraulic model coupled with a demand forecasting methodology and several statistical techniques to process the hydraulic meters data (i.e., flows and pressures) coming from the field at regular time intervals (i.e. every 15 minutes). Once the detection part of the methodology identifies a potential burst occurrence in a system it raises an alarm. This is followed by the application of the burst localisation methodology to approximately locate the event within the District Metered Area (DMA). The online hydraulic model is based on data assimilation methodology coupled with a short-term Water Demand Forecasting Model (WDFM) based on Multi-Linear Regression. Three data assimilation methods were tested in the thesis, namely the iterative Kalman Filter method, the Ensemble Kalman Filter method and the Particle Filter method. The iterative Kalman Filter (i-KF) method was eventually chosen for the online hydraulic model based on the best overall trade-off between water system state prediction accuracy and computational efficiency. The online hydraulic model created this way was coupled with the Statistical Process Control (SPC) technique and a newly developed burst detection metric based on the moving average residuals between the predicted and observed hydraulic states (flows/pressures). Two new SPC-based charts with associated generic set of control rules for analysing burst detection metric values over consecutive time steps were introduced to raise burst alarms in a reliable and timely fashion. The SPC rules and relevant thresholds were determined offline by performing appropriate statistical analysis of residuals. The above was followed by the development of the new methodology for online burst localisation. The methodology integrates the information on burst detection metric values obtained during the detection stage with the new sensitivity matrix developed offline and hydraulic model runs used to simulate potential bursts to identify the most likely burst location in the pipe network. A new data algorithm for estimating the ‘normal’ DMA demand and burst flow during the burst period is developed and used for localisation. A new data algorithm for statistical analysis of flow and pressure data was also developed and used to determine the approximate burst area by producing a list of top ten suspected burst location nodes. The above novel methodologies for burst detection and localisation were applied to two real-life District Metred Areas in the United Kingdom (UK) with artificially generated flow and pressure observations and assumed bursts. The results obtained this way show that the developed methodology detects pipe bursts in a reliable and timely fashion, provides good estimate of a burst flow and accurately approximately locates the burst within a DMA. In addition, the results obtained show the potential of the methodology described here for online burst detection and localisation in assisting Water Companies (WCs) to conserve water, save energy and money. It can also enhance the UK WCs’ profile customer satisfaction, improve operational efficiency and improve the OFWAT’s Service Incentive Mechanism (SIM) scores.

In this thesis, we produce a rigorous and quantitative analysis of the errors introduced by finite difference schemes into strong constraint 4D-Variational (4D-Var) data assimilation. Strong constraint 4D-Var data assimilation is a method that solves a particular kind of inverse problem; given a set of observations and a numerical model for a physical system together with a priori information on the initial condition, estimate an improved initial condition for the numerical model, known as the analysis vector. This method has many forms of error affecting the accuracy of the analysis vector, and is derived under the assumption that the numerical model is perfect, when in reality this is not true. Therefore it is important to assess whether this assumption is realistic and if not, how the method should be modified to account for model error. Here we analyse how the errors introduced by finite difference schemes used as the numerical model, affect the accuracy of the analysis vector. Initially the 1D linear advection equation is considered as our physical system. All forms of error, other than those introduced by finite difference schemes, are initially removed. The error introduced by `representative schemes' is considered in terms of numerical dissipation and numerical dispersion. A spectral approach is successfully implemented to analyse the impact on the analysis vector, examining the effects on unresolvable wavenumber components and the l2-norm of the error. Subsequently, a similar also successful analysis is conducted when observation errors are re-introduced to the problem. We then explore how the results can be extended to weak constraint 4D-Var. The 2D linear advection equation is then considered as our physical system, demonstrating how the results from the 1D problem extend to 2D. The linearised shallow water equations extend the problem further, highlighting the difficulties associated with analysing a coupled system of PDEs.