La littérature économique attribuant des rôles endogènes à l'évolution technologique et à lagéographie pour expliquer la croissance économique suggère que la compréhension des fluxde connaissances dans l'espace et de leurs conséquences sur les activités d'innovation est aucoeur de l'explication des disparités dans la croissance économique. À cet égard, cette thèsemet l'accent sur les réseaux de connaissances comme un mécanisme permettant la circulationdes connaissances dans l'espace et le temps. Parmi les différents types de réseaux deconnaissances, elle étudie les réseaux de collaboration de R&D et explore deux questionsprincipales.Tout d'abord, elle examine l'effet de la géographie sur la formation du réseau pour savoir si lesflux de connaissances par les réseaux de collaboration en R&D sont limités dans l'espace oupas. Elle s'enquiert de cette question à la fois pour le réseau multilatéral entre lesorganisations et le réseau inter-régional entre les régions européennes dans le domaine desbiotechnologies en utilisant les données sur les collaborations de R&D promues par lesProgrammes-Cadres Européens.Deuxièmement, elle explore comment un réseau évolutif de collaborations de R&D entre lesrégions affecte les performances des régions en matière d'innovation. Elle utilise l'économétriespatiale pour quantifier les effets statiques et dynamiques des flux de connaissances desvoisins spatiaux et d'un ensemble évolutif de partenaires de collaboration sur l'activitéinventive des régions dans le domaine des TIC au cours de la période 2003-2009. / The economic literature attributing endogenous roles to technological change and geography inexplaining economie growth suggests that understanding knowledge flows in space and theirconsequences on innovative activities is central to explaining disparities in economie growth. Inthis regard, this PhD thesis focuses on knowledge networks as a mechanism that enablesknowledge flows in space and time. Among different types of knowledge networks, it studiesR&D collaboration networks and addresses two main issues.First, it investigates the effect of geography on network formation to figure out whetherknowledge flows through R&D collaboration networks are constrained in space or not. It inquiresthis question both for multilateral R&D collaboration network among organizations and theresulting inter-regional network among European regions in the field of biotechnology using dataon R&D collaborations promoted via European Framework Programmes.Second, it addresses how an evolving network of R&D collaborations among regions affectsregional innovation performances in time. It employs a spatial econometric approach to quantifythe static and dynamic effects of knowledge flows from spatial neighbors and an evolving set ofcollaboration partners on inventive activity of regions in the field of ICT durin 2003-2009.

The aim of this master thesis is to analyze the development of capital flows within the euro area and within selected Member States, with respect to the hypothesis of a sufficient replacement of private capital flows with official ones. Verification of the hypothesis is based on identifying sudden changes in capital flows, using the model created by Mr.Forbes and Mr.Warnock. The entire work is conceived into three main chapters. The first is dedicated to the development of the crisis in the euro area and the adoption of important reform measures as response to the resulting unfavorable situation. The second chapter deals with the definition of net and gross capital flows and their development in the so-called extra-area flows. The final section is focused on the analysis of intra-area capital flows and flows in selected member countries.

The evolving complexity of electric power systems with higher levels of uncertainties is a new challenge faced by system operators. Therefore, new methods for power system prediction, monitoring and state estimation are relevant for the efficient exploitation of renewable energy sources and the secure operation of network assets. In order to estimate all possible operating conditions of power systems, this Thesis proposes the use of Gaussian mixture models to represent non-Gaussian correlated input variables, such as wind power output or aggregated load demands in the probabilistic load flow problem. The formulation, based on multiple Weighted Least Square runs, is also extended to monitor distribution radial networks where the uncertainty of these networks is aggravated by the lack of sufficient real-time measurements. This research also explores reduction techniques to limit the computational demands of the probabilistic load flow and it assesses the impact of the reductions on the resulting probability density functions of power flows and bus voltages. The development of synchronised measurement technology to support monitoring of electric power systems in real-time is also studied in this work. The Thesis presents and compares different formulations for incorporating conventional and synchronised measurements in the state estimation problem. As a result of the study, a new hybrid constrained state estimator is proposed. This constrained formulation makes it possible to take advantage of the information from synchronised phasor measurements of branch currents and bus voltages in polar form. Additionally, the study is extended to assess the advantages of PMU measurements in multi-area state estimators and it explores a new algorithm that minimises the data exchange between local area state estimators. Finally, this research work also presents the advantages of dynamic state estimators supported by Synchronised Measurement Technology. The dynamic state estimator is compared with the static approach in terms of accuracy and performance during sudden changes of states and the presence of bad data. All formulations presented in this Thesis were validated in different IEEE test systems.

De part et d’autre de la Terre, on observe de plus en plus de phénomènes naturels dévastateurs, parmi lesquels les inondations constituent l’une des catastrophes les plus fréquentes. Ces dernières décennies d’importantes inondations ont été induites par les crues de rivières. Ces crues, dues à des pluies excessives ou aux eaux de ruissellement, causent sans cesse des pertes de vies humaines et des dégâts matériels importants. Pour remédier à ces problèmes, les réseaux hydrographiques sont de plus en plus équipés de moyens de détection de crues. Un facteur essentiel à la gestion de tels phénomènes est la réactivité. En effet, les gestionnaires des réseaux hydrographiques, dans ce genre de situation, doivent prendre rapidement des décisions importantes dans un contexte incertain, car la plupart de ces crues sont le fruit de phénomènes climatiques brusques, dont l’ampleur est difficile à évaluer avec précision. Nous proposons, dans ce mémoire, une méthode de gestion des crues dans des réseaux hydrographiques équipés de zones inondables contrôlées par des portes gravitationnelles. Dans un premier temps, nous avons modélisé notre méthode de gestion à l’aide d’un réseau de transport statique. Dans un second temps, nous l’avons enrichi en utilisant les réseaux de transport à retards dans le but de prendre en compte les temps de déplacement de la ressource gérée. Afin de pallier le problème de la taille importante des réseaux de transport à retards, nous avons élaboré un mécanisme de substitution combinant un réseau de transport statique réduit et une matrice de temporisation. De plus, ce mécanisme autorise la prise en compte des temps de transfert variables dépendant des débits, sans modification ni du réseau de transport, ni de la structure de la matrice de temporisation. Ce mécanisme permet donc une gestion simplifiée des temps de transferts, variables ou non. Avec ce mécanisme, l’évaluation du flot maximal à coût minimum, nous a permis, suivant les stratégies de gestion considérées, de consigner l’ouverture des portes des zones inondables afin d’écrêter la crue mais aussi afin de restituer cette eau stockée au moment opportun. Finalement, afin d’évaluer les apports de cette gestion, la méthode a été appliquée sur un cas d’étude basée sur un tronçon de rivière équipé de trois zones inondables et modélisé à l’aide de simulateurs hydrauliques combinant les approches de modélisation 1D et 2D. Les résultats de simulation obtenus ont montré que l’approche proposée permettait de réduire de manière significative les inondations en aval des cours d’eau. / On either side of the Earth, we observe more and more devastating natural phenomena. Amon these phenomena, floods are one of the most frequent and devastating natural disasters. During these last decades extensive flooding were caused by the flood of rivers. These floods due to excessive rainfall or runoff induce invariably the loss of human lives and material damages. To overcome these problems, water systems are increasingly equipped with means for detecting floods. A key factor in the management of such phenomena is responsiveness. Indeed, managers of river systems, faced to this kind of situation should quickly take important decisions in an uncertain context, as most of these floods are induced by abrupt climate events, whose magnitude is difficult to assess accuracy. We propose in this dissertation, a method of flood management in river systems equipped with flood zones controlled by gravitational gates. At first, we modeled our management method using a static transportation network. In a second step, we enriched it by using transportation networks with delays in order to take into account the travel time of the managed resource. The main difficulty of transportation networks with delays is their oversize. To overcome this problem, we developed an alternative mechanism combining a static reduced transportation network with a temporization matrix. Furthermore, this mechanism allows the consideration of variable time transfer depending on flows, without modification either on the transportation network, or on the structure of the temporization matrix. This mechanism allows simplified management of the transfer times, variable or not. With this mechanism, the evaluation of the minimum cost maximum flow allowed us, according to the management strategies considered, to compute the gate opening for floodplains in order to mitigate the flood but also to restore the water stored at the relevant time. Finally, to evaluate the contributions of this management, the method was applied to a case study based on a section of river equipped with three flood control reservoirs areas modeled using hydraulic simulators combining 1D and 2D models. The simulation results showed that the proposed approach allowed reducing significantly the floods downstream watercourses.

Bakgrund: En bostadsrättsförening är ingen kommersiell verksamhet och drivs inte i vinstsyfte. Resultaträkningen kan därmed inte anses avgörande för bostadsrättsföreningars ekonomiska välmående. Det som bör betonas är föreningens kassaflödesanalys som visar finansiella flöden, samt behovet att göra avsättningar för att möta framtida underhåll. Således bör kompletterande information om bostadsrättsföreningars ekonomiska situation tillföras årsredovisningen. Syfte: Syftet är att undersöka om K2-redovisande bostadsrättsföreningar bör komplettera sina årsredovisningar med en kassaflödesanalys för att ge en bättre bild av ekonomiskt välmående. Metod: Studien utgår ifrån en kvalitativ forskningsstrategi. Empirisk data har samlats in genom semi-strukturerade intervjuer. Studiens respondenter består av tre av Sveriges största aktörer inom fastighetsförvaltning, samt en auktoriserad revisor på EY. Resultat: K2-redovisande bostadsrättsföreningar bör komplettera sina årsredovisningar med en kassaflödesanalys. En kassaflödesanalys bidrar till förståelse för betalningsströmmar under ett räkenskapsår, vilket förtydligar hur likvida medel har använts. Ett positivt kassaflöde bidrar till ett ökat ekonomiskt välmående hos bostadsrättsföreningar, eftersom likvida medel kan användas till att betala amorteringar, underhåll och investeringar. Kassaflödesanalysen bidrar således till att ge en bättre bild av bostadsrättsföreningars ekonomiska välmående. Författarna betonar dock att kassaflödesanalysen ensam inte bidrar till en komplett bild av bostadsrättsföreningars ekonomiska välmående. Årsredovisningen bör även kompletteras med nyckeltal. Vidare bör en underhållsplan upprättas samt avsättningar göras till yttre fond. / Background: Housing associations are not a commercial activity and are profit driven. The income statement can therefore not be described as crucial for housing associations. However, what should be emphasized are the association’s cash flow statements that shows the financial flows and also the need to make provisions to meet future maintenance. Thus, additional information of housing associations financial situation should be added to the annual report. Purpose: The purpose is to investigate whether housing associations reporting according to K2 should supplement their financial statement with a cash flow analysis to provide a clearer measure of economic wellbeing. Method: The study is based on an qualitative research strategy. Empirical data were collected through semi-structured interviews. The respondents consist of three of the largest companies for housing administration, as well as an accountant at EY. Result: K2-reporting housing associations should complement their annual reports with a cash flow statement. A cash flow statement contributes to the understanding of the past year´s cash flows, which clarifies how cash is used. A positive cash flow contributes to better economic wellbeing for housing associations, because cash can be used to pay debt service, maintenenace and investments. Cash flow statements helps to give a better picture of the economic wellbeing of housing associations. The authors, however, states that a cash flow analysis alone does not contribute to a complete picture of the economic wellbeing of housing associations. The annual report should also be supplemented with key figures. Furthermore, maintenance is established and provisions made to the external fund.

A preocupação mundial com a sustentabilidade tem levado as organizações a investigar, cada vez mais, alternativas para melhorar a sua desempenho ambiental e, assim, garantir o desenvolvimento dos seus negócios de forma sustentável. Com o passar dos anos, a literatura tem apresentado diferentes estratégias para apoiar a evolução de empresas ambientalmente conscientes, embora muito pouco tenha se explorado com relação ao potencial para promover a sustentabilidade inerente às práticas de manufatura já existentes. Com o propósito de promover o desenvolvimento de uma cultura de melhoria contínua, lean thinking, ou pensamento enxuto, descreve uma filosofia de trabalho aplicada por muitas empresas de manufatura, a qual foca a eliminação de desperdícios e a aplicação de recursos somente onde há criação de valor para o cliente final. Seguindo essa ideia, o mesmo pensamento de se fazer mais com menos do lean thinking pode ser adaptado para a melhoria dos fluxos que são suporte à produção, isto é materiais, energia e geração de resíduos os quais causam significativo impacto ambiental, contribuindo, assim, para o desenvolvimento de negócios mais sustentáveis. A literatura apresenta diversas evidencias nas quais não só o uso da filosofia lean ajudou na redução de impacto ambiental, mas também exemplos em que a integração dos conceitos de lean e meio ambiente, Lean e Green, é positiva e complementar para redução de resíduos e perdas na produção. Entretanto, não foram encontrados outros estudos com o propósito especifico de utilizar o lean para redução do impacto ambiental na manufatura, incluindo a utilização de um pré-requisito, em termos de nível de desenvolvimento e conhecimento de lean, como requerimento crítico para sua aplicabilidade. O principal objetivo desse projeto é propor um novo modelo, chamado de Lean & Green Business Model (L&GBM). Integrando conceitos de lean e meio ambiente através do desenvolvimento de kaizens em células e em todo fluxo de produção, o modelo desenvolvido tem como principal objetivo a redução do impacto ambiental gerado pelos processos produtivos. O projeto desenvolvido reporta os resultados da aplicação do Modelo Lean e Green em uma corporação multinacional de engenharia, incluindo os resultados do desdobramento do mesmo em diferentes circunstancias: (1) teste piloto em duas células, (2) aplicação do modelo em sete células, (3) aplicação do modelo para células irmãs, (4) aplicação do modelo para fluxo de produção, (5) aplicação do modelo em diferentes ambientes da manufatura. Alguns dos principais resultados identificados até este momento através do desenvolvimento dessa pesquisa incluem: (i) L&GBM é uma boa estratégia de prevenção da poluição, reduzindo de 12 a 35% a aplicação dos fluxos de massa e energia, (ii) L&GBM pode ser usado para reduzir custos, isto é, custos da manufatura de 2 a 8%, (iii), L&GBM adiciona uma nova dimensão ao modelo tradicional de lean, (iv) L&GBM integra completamente os conceitos de lean e sustentabilidade ambiental e (v) L&GBM requer um nível de estabilidade na manufatura para ser aplicado. / Global awareness regarding environmental sustainability has prompted enterprises to investigate different alternatives for improving environmental performance in order to deploy sustainable businesses. There is a growing body of literature proposing different sustainability alternatives for environmentally-conscious firms, although not many have really explored the sustainability side of existent manufacturing strategies. With the purpose of promoting a continuous improvement culture within the business, lean thinking describes a working philosophy applied by many manufacturers, which considers the expenditure of resources for any goal other than the creation of value for the end customer, to be wasteful. Therefore, the same idea of doing more with less from lean thinking can be applied for improving material, energy flows and wastes streams that cause significant environmental impacts, thus supporting the development of a sustainable business. There has been lots of anecdotal evidence that a lean approach can help make the business case for environmental impact reduction and an integrated Lean and Green works for (1) reduction of production waste, (2) reduction of environmental impact but little empirical evidence to substantiate this. The main objective of this project is to propose a new model, which is called Lean & Green Business Model (L&GBM). In this model, environmental sustainability is integrated into pure lean thinking. The model presented in here adopts a Kaizen approach to improve mass and energy flows in manufacturing environments that already possess the necessary deployment level to apply lean thinking. Evidence-based results are first reviewed. It is presented findings to support the need of manufacturing stability as a prerequisite for integrating lean and green at the manufacturing level. The integrated lean and green approach results in (i) a reduction in production waste and (ii) a reduction in environmental impact. The project reports the findings of application of the model in a major engineering international corporation, including the results of the model deployment in several different circumstances: (1) pilot testing in two cells, (2) cell roll out in seven cells, (3) application for sisters’ cells, (4) application for a value stream and (5) application in different manufacturing environments. Some of the research key findings identified include: (i) L&GBM is a good pollution prevention strategy, reducing from 12 to 35% mass and energy flows, (ii) L&GBM can be used to reduce costs, reducing operational manufacturing mass and energy flow costs by 2 to 8%, (iii) L&GBM introduces a new dimension into traditional lean thinking, the environmental concerns, motivating a conceptual transition, (iv) L&GBM fully integrates lean thinking and green thinking, merging the fundamental principles of lean and green thinking (v) L&GBM requires a sufficient level of manufacturing stability and lean deployment prior to its introduction.

Dans la première partie de cette thèse, nous introduisons une nouvelle généralisation de l'opérateur de Laplace en géométrie de Finsler. Cette opérateur est défini en intégrant le long des fibres les dérivées directionnelles secondes d'une fonction par rapport à une mesure d'angle que nous construisons. Nous obtenons un opérateur différentiel d'ordre ..., elliptique, symétrique, et qui admet une bonne théorie spectrale. Nous calculons des exemples explicites de spectres pour des métriques de Katok-Ziller. En courbure négative, nous prouvons, grâce à un théorème d'Ancona que la frontière de Martin est Hölder-homéomorphe à la frontière visuelle. Ceci nous permet de déduire l'existence et l'ergodicité des mesures harmoniques pour cet opérateur. Dans la seconde partie, nous étudions les flots d'Anosov en dimension ... dont l'espace des feuilles est homéomorphe à .... Lorsque la variété est hyperbolique, Thurston démontra que le feuilletage (in)stable induit un flot ''orthogonal'' au premier. Nous utilisons ce second flot pour étudier les classes d'isotopie d'orbites périodiques du flot d'Anosov, ainsi que l'existence de cylindres plongés. / In the first part of this dissertation, we give a new definition of a Laplace operator for Finsler metric as an average, with regard to an angle measure, of the second directional derivatives. This operator is elliptic, symmetric with respect to the Holmes-Thompson volume, and coincides with the usual Laplace--Beltrami operator when the Finsler metric is Riemannian. We compute explicit spectral data for some Katok-Ziller metrics. When the Finsler metric is negatively curved, we show, thanks to a result of Ancona that the Martin boundary is Hölder-homeomorphic to the visual boundary. This allow us to deduce the existence of harmonic measures and some ergodic preoperties. In the second part of this dissertation, we study Anosov flows in 3-manifolds, with leaf-spaces homeomorphic to .... When the manifold is hyperbolic, Thurston showed that the (un)stable foliations induces an "orthogonal" flow. We use this second flow to study isotopy class of periodic orbits of the Anosov flow and existence of embedded cylinders.

O objetivo deste trabalho é desenvolver um método numérico capaz de simular escoamentos viscoelásticos com superfícies livres governados pela equação constitutiva não-linear PTT (Phan-Thien-Tanner). Neste trabalho foram apresentados três métodos numéricos para simular escoamentos viscoelásticos modelados pela equação PTT. Dois desses métodos foram desenvolvidos para simular escoamentos viscoelásticos bidimensionais enquanto o terceiro método foi desenvolvido para simular escoamentos viscoelásticos tridimensionais. Estes métodos numéricos foram incorporados aos ambientes de simulação FreeDow2D e FreeDow3D, extendendo estes ambientes para escoamentos viscoelásticos descritos por uma equação constitutiva não-linear. Inicialmente, uma descrição de FreeDow2D e FreeDow3D é apresentada. As equações governantes para escoamentos descritos pelo modelo PTT são dadas na forma de tensorial e as formulações matemáticas para obtenção dos métodos numéricos são apresentadas. As equações que descrevem os métodos numéricos são resolvidas pela técnica de diferenças finitas numa malha deslocada e o fluido é representado por partículas arcadoras usando o método Marker-and-Cell. As condições de contorno para cada tipo de contorno são descritas em detalhes e o cálculo do tensor extra-tensão no contorno rígido é obtido utilizando as idéias de Tomé et al. [84] para o modelo Oldroyd-B. Seguindo a metodologia de Alves et al. [2], a solução analítica do modelo PTT para escoamentos totalmente desenvolvidos em um canal bidimensional é apresentada em detalhes. Esta solução analítica é então usada para validar o método numérico desenvolvido neste trabalho. Os métodos numéricos desenvolvidos nesse trabalho foram aplicados para simular os seguintes problemas: um jato de fluido viscoelástico incidindo numa placa rígida; o inchamento do extrudado e o problema de uma gota esférica de fluido viscoelástico incidindo perpendicularmente contra uma superfície rígida plana / The aim of this work is to develop a numerical method capable of simulating viscoelastic free surface flows governed by the non-linear constitutive equation PTT (Phan-Thien-Tanner). In this work three numerical methods to simulate vicoelastic Flows of fluids modelled by the PTT equation are presented. Two of these methods were developed to simulate two-dimensional viscoelastic flows while the third method was developed to simulate three-dimensional viscoelastic flows. These numerical methods were incorporated into the codes FreeFlow2D and FreeFlow3D, extending these codes to viscoelastic flows described by the non-linear constitutive equation PTT. Initially, a description of FreeFlow2D and FreeFlow3D is presented. The governing equations for flows described by the PTT model are given in index form and the mathematical formulations for obtaining the numerical methods are presented. The equations describing the numerical methods are solved by the finite difference method on a staggered grid and the fluid is modelled using a Marker-and-Cell type method. The boundary conditions for each type of boundary are described in details and the calculation of the extra-stress tensor on rigid boundaries is performed using the ideas of Tomé et al. [84] for an Oldroyd-B Fluid. Following the methodology presented by Alves et al. [2], the analytic solution of the PTT model for fully developed flows in a two-dimensional channel is presented in details. This analytic solution is then used to validate the numerical method developed in this work. Finally, the numerical methods developed in this work were applied to simulate viscoelastic flows such as a viscoelastic jet flowing onto a rigid plate, the extrudate swell of viscoelastic fluids and the simulation of a viscoelastic drop hitting a rigid plate

Este trabalho descreve um método para expandir a aplicabilidade do sistema FreeFlow-2D para problemas de escoamentos de fluidos multifásicos. Este método permite a simulação de escoamento de fluido multifásico, incompressível e com superfície livre. Um número arbitrário de fases com propriedades diferentes pode ser utilizado. Tensões superficial e interfacial são também consideradas. A técnica numérica utilizada baseia-se no GENSMAC (Generalized-Simplified-Marker-and-Cell) e consideram-se propriedades variáveis de acordo com a posição da interface durante o escoamento. O campo de velocidade é computado utilizando-se às equações de Navier-Stokes discretizadas por esquema de diferença finita numa malha deslocada. O método foi implementado em três módulos: Modelador, Simulador e Visualizador. A validação foi efetuada comparando-se os resultados numéricos com resultados analíticos e experimentais. O método mostrou-se robusto e computacionalmente eficiente para os problemas considerados. / This work describes a method to expand the applicability of the system FreeFlow-2D in multi-phase flows problems. This method allows the simulation of incompressible free surface multi-phase flows. An arbitrary number of phases having different properties can be used. Surface and interface tension effects are also considered. The numerical technique is based on the GENSMAC (Generalized-Simplified-Marker-and-Cell) and it considers the properties varying according to the position of the interfaces in the flow. The velocity field is computed using the Navier-Stokes equations discretized by finite-difference on stagered grid. The method was implemented in three modules: the modeling module, the simulation module, and the visualization module. The validation was effected by comparing numerical results with analytical and experimental results. The method shown to be robust and computationally efficient in the problems considered.

O tema deste trabalho é o estudo de métodos numéricos para a simulação de escoamentos incompressíveis com superfície livre a baixos Reynolds, por meio da metodologia GENSMAC e suas formulações explícita e implícita. Neste contexto, temos especial interesse na formulação implícita, objetivando o enfraquecimento da restrição de estabilidade parabólica no passo temporal em escoamentos com superfície livre. O trabalho pode ser dividido em duas partes: na primeira, algumas modificações são discutidas, propostas e testadas com o objetivo de tornar a formulação implícita mais eficiente e precisa; em seguida, aproveitamos os resultados obtidos e generalizamos o método numérico existente para simular escoamentos viscoelásticos modelados pela equação constitutiva SXPP. Em ambos os casos, a formulação explícita também é usada para comparação e teste. Resultados que demonstram a eficiência e robustez das técnicas desenvolvidas são apresentados por meio da simulação numérica de complexos problemas envolvendo superfície livre.O tema deste trabalho é o estudo de métodos numéricos para a simulação de escoamentos incom- pressíveis com superfície livre a baixos Reynolds, por meio da metodologia GENSMAC e suas formulações explícita e implícita. Neste contexto, temos especial interesse na formulação implícita, objetivando o en- fraquecimento da restrição de estabilidade parabólica no passo temporal em escoamentos com superfície livre. O trabalho pode ser dividido em duas partes: na primeira, algumas modificações são discutidas, propostas e testadas com o objetivo de tornar a formulação implícita mais eficiente e precisa; em seguida, aproveitamos os resultados obtidos e generalizamos o método numérico existente para simular escoamentos viscoelásticos modelados pela equação constitutiva SXPP. Em ambos os casos, a formulação explícita também é usada para comparação e teste. Resultados que demonstram a eficiência e robustez das técnicas desenvolvidas são apresentados por meio da simulação numérica de complexos problemas envolvendo superfície livre / The purpose of this work is the study of numerical methods for low Reynolds number incompressible free surface flows, including the GENSMAC methodology and its explicit and implicit formulations. In this context, we have special interest in the implicit formulation, in order to circumvent the parabolic stability restriction in the time step for free surface flows. The work can be divided into two parts: firstly, some modifications are proposed, discussed, and tested with the purpose of making the implicit formulation more e¢ cient and accurate; secondly, we take advantage of the results derived in the first part to generalize the numerical method for simulating viscoelastic free surface flows modeled by the constitutive equation SXPP. In both cases, the explicit formulation is also used for comparison and tests. Results that demonstrate the e¢ ciency and robustness of the developed techniques are presented and illustrated by the numerical simulation of complex problems involving free surface flows