[pt] As descargas atmosféricas são de grande importância para o setor elétrico, sendo frequentemente responsáveis por desligamentos de linhas de transmissão, que podem desencadear uma sequência de eventos que levem o sistema elétrico interligado ao colapso. As longas extensões de linhas de transmissão, expostas a intemperes climáticas, determinam uma probabilidade significativa de incidência direta de descargas atmosféricas nestes equipamentos. Devido ao caráter estratégico das linhas para o fornecimento de energia e a constatação de que descargas atmosféricas estão entre as principais causas de desligamentos, torna-se importante o estudo do comportamento das descargas atmosféricas, antes do instante da ocorrência do desligamento das linhas de transmissão, para compreender os padrões característicos potenciais causadores destes desligamentos. Os estudos encontrados atualmente estão orientados na eficiência das redes de detecção de descargas atmosféricas e na identificação de condições climáticas que indiquem a ocorrência de raios de forma preditiva, sem correlação a ocorrências em linhas de transmissão. Assim, essa dissertação consiste na determinação do risco de desligamentos de linhas de transmissão por descargas atmosféricas, visando fornecer informações antecipadas e possibilitar ações operativas para manter a segurança do sistema elétrico. O modelo desenvolvido nesse estudo, denominado Risco de Desligamentos de Linhas de Transmissão por Raios (RDLR), é composto de dois módulos principais, sendo o primeiro o agrupamento do conjunto amostral de descargas atmosféricas, realizado através de um método baseado em densidade. Nesse módulo, os ruídos são eliminados de forma eficiente e são formados grupos representativos de descargas atmosféricas. O segundo módulo consiste em uma etapa classificatória, baseado em redes neurais artificiais para identificar padrões de grupos de descargas que representem riscos de desligamentos de linhas de transmissão. Visando a otimização do modelo, foi aplicado um método de seleção das variáveis, através de componentes principais, para determinar aquelas que mais contribuem na caracterização desses eventos. O modelo RDLR foi testado com dados reais dos registros de desligamentos de linhas de transmissão, associado a outro banco com dados reais contendo milhões de registros de descargas atmosféricas oriundos das redes de detecção de raios, sendo obtidos excelentes resultados na determinação dos riscos de desligamentos de linhas de transmissão por descargas atmosféricas. / [en] Atmospheric discharges are of great importance to power systems, and are often responsible for outages of transmission lines, which can trigger a sequence of events that leads to a system collapse. The long extensions of transmission lines, exposed to climatic conditions, create significant probability of direct incidence of atmospheric discharges in these equipments. Due to the strategic nature of power supply lines and the fact that atmospheric discharges are among the main causes of outages, it is important to study atmospheric discharges characteristics before failure of transmission lines and understand patterns that are responsible for interruptions. Current studies focus on efficiency of lightning detection networks and on identification of climatic conditions that indicate lightning occurrence in a predictive approach, without any correlation with transmission lines outages. Therefore, this thesis consists on real-time risk determination of transmission lines outage by lightning, providing early information to enabling operational procedures for power system safety. The proposed model, named Transmission Lines Outage Risk by Lightning (TLORL) is composed of two main modules: Atmospheric Discharge Data Clustering and Classification. In the atmospheric discharges data-clustering module, performed by a density-based method, the outages are efficiently eliminated and representative groups of atmospheric discharges are formed. The second module consists of a classification step, based on artificial neural networks, to identify patterns of discharges groups that represent risks to cause transmission lines outages. Aiming at improving the proposed model, principal components analysis (PCA) was applied to determine the input variables that most contribute to the events characterization. The TLORL model was tested with real data transmission line outages, associated to another database with millions lightning records from the detection networks, producing excellent results of transmission lines outages caused by atmospheric discharges.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2016-07-01T15:05:14Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Souza_Tese_2015_09_22.pdf: 8187999 bytes, checksum: 664629aed28d692dce410fefbfe793dc (MD5) / Made available in DSpace on 2016-07-01T15:05:14Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Souza_Tese_2015_09_22.pdf: 8187999 bytes, checksum: 664629aed28d692dce410fefbfe793dc (MD5) Previous issue date: 2015-09-22 / Anp / Sob certas hipóteses simplificadoras, o modelo matemático que descreve o escoamento de água e óleo em reservatórios de petróleo pode ser representado por um sistema não linear de Equações Diferenciais Parciais composto por uma equação elíptica de pressão (fluxo) e uma equação hiperbólica de saturação (transporte). Devido a complexidades na modelagem de ambientes deposicionais, nos quais são incluídos camadas inclinadas, canais, falhas e poços inclinados, há uma dificuldade de se construir um modelo que represente adequadamente certas características dos reservatórios, especialmente quando malhas estruturadas são usadas (cartesianas ou corner point). Além disso, a modelagem do escoamento multifásico nessas estruturas geológicas incluem descontinuidades na variável e instabilidades no escoamento, associadas à elevadas razões de mobilidade e efeitos de orientação de malha. Isso representa um grande desafio do ponto de vista numérico. No presente trabalho, uma formulação fundamentada no Método de Volumes Finitos é estudada e proposta para discretizar as equações elíptica de pressão e hiperbólica de saturação. Para resolver a equação de pressão três formulações robustas, com aproximação dos fluxos por múltiplos pontos são estudadas. Essas formulações são abeis para lidar com tensores de permeabilidade completos e malhas poligonais arbitrárias, sendo portanto uma generalização de métodos mais tradicionais com aproximação do fluxo por apenas dois pontos. A discretização da equação de saturação é feita com duas abordagens com característica multidimensional. Em uma abordagem mais convencional, os fluxos numéricos são extrapolados diretamente nas superfícies de controle por uma aproximação de alta resolução no espaço (2ª a 4ª ordem) usando uma estratégia do tipo MUSCL. Uma estratégia baseada na Técnica de Mínimos Quadrados é usada para a reconstrução polinomial. Em uma segunda abordagem, uma variação de uma esquema numérico Verdadeiramente Multidimensional é proposto. Esse esquema diminui o efeito de orientação de malha, especialmente para malhas ortogonais, mesmo embora alguma falta de robustez possa ser observada pra malhas excessivamente distorcidas. Nesse tipo de formulação, os fluxos numéricos são calculados de uma forma multidimensional. Consiste em uma combinação convexa de valores de saturação ou fluxo fracionário, seguindo a orientação do escoamento através do domínio computacional. No entanto, a maioria dos esquemas numéricos achados na literatura tem aproximação apenas de primeira ordem no espaço e requer uma solução implícita de sistemas algébricos locais. Adicionalmente, no presente texto, uma forma modificada desses esquemas “Verdadeiramente” Multidimensionais é proposta em um contexto centrado na célula. Nesse caso, os fluxos numéricos multidimensionais são calculados explicitamente usando aproximações de alta ordem no espaço. Para o esquema proposto, a robustez e o caráter multidimensional também leva em conta a distorção da malha por meio de uma ponderação adaptativa. Essa ponderação regula a característica multidimensional da formulação de acordo com a distorção da malha. Claramente, os efeitos de orientação de malha são reduzidos. A supressão de oscilações espúrias, típicas de aproximações de alta ordem, são obtidas usando, pela primeira vez no contexto de simulação de reservatórios, uma estratégia de limitação multidimensional ou Multidimensional Limiting Process (MLP). Essa estratégia garante soluções monótonas e podem ser usadas em qualquer malha poligonal, sendo naturalmente aplicada em aproximações de ordem arbitrária. Por fim, de modo a garantir soluções convergentes, mesmo para problemas tipicamente não convexos, associados ao modelo de Buckley-Leverett, uma estratégia robusta de correção de entropia é empregada. O desempenho dessas formulações é verificado com a solução de problemas relevantes achados na literatura. / Under certain simplifying assumptions, the problem that describes the fluid flow of oil and water in heterogeneous and anisotropic petroleum reservoir can be described by a system of non-linear partial differential equations that comprises an elliptic pressure equation (flow) and a hyperbolic saturation equation (transport). Due to the modeling of complex depositional environments, including inclined laminated layers, channels, fractures, faults and the geometrical modeling of deviated wells, it is difficult to properly build and handle the Reservoir Characterization Process (RCM), particularly by using structured meshes (cartesian or corner point), which is the current standard in petroleum reservoir simulators. Besides, the multiphase flow in such geological structures includes the proper modeling of water saturation shocks and flow instabilities associated to high mobility ratios and Grid Orientation Effects (GOE), posing a great challenge from a numerical point of view. In this work, a Full Finite Volume Formulation is studied and proposed to discretize both, the elliptic pressure and the hyperbolic saturation equations. To solve the pressure equation, we study and use three robust Multipoint Flux Approximation Methods (MPFA) that are able to deal with full permeability tensors and arbitrary polygonal meshes, making it relatively easy to handle complex geological structures, inclined wells and mesh adaptivity in a natural way. To discretize the saturation equation, two different multidimensional approaches are employed. In a more conventional approach, the numerical fluxes are extrapolated directly on the control surfaces for a higher resolution approximation in space (2nd to 4th order) by a MUSCL (Monotone Upstream Centered Scheme for Conservation Laws) procedure. A least squares based strategy is employed for the polynomial reconstruction. In a second approach, a variation of a “Truly” Multidimensional Finite Volume method is proposed. This scheme diminishes GOE, especially for orthogonal grids, even though some lack of robustness can be observed for extremely distorted meshes. In this type of scheme, the numerical flux is computed in each control surface in a multidimensional way, by a convex combination of the saturation or the fractional flow values, following the approximate wave orientation throughout the computational domain. However, the majority of the schemes found in literature is only first order accurate in space and demand the implicit solution of local conservation problems. In the present text, a Modified Truly Multidimensional Finite Volume Method (MTM-FVM) is proposed in a cell centered context. The truly multidimensional numerical fluxes are explicitly computed using higher order accuracy in space. For the proposed scheme, the robustness and the multidimensional character of the aforementioned MTM-FVM explicitly takes into account the angular distortion of the computational mesh by means of an adaptive weight, that tunes the multidimensional character of the formulation according to the grid distortion, clearly diminishing GOE. The suppression of the spurious oscillations, typical from higher order schemes, is achieved by using for the first time in the context of reservoir simulation a Multidimensional Limiting Process (MLP). The MLP strategy formally guarantees monotone solutions and can be used with any polygonal mesh and arbitrary orders of approximation. Finally, in order to guarantee physically meaningful solutions, a robust “entropy fix” strategy is employed. This produces convergent solutions even for the typical non-convex flux functions that are associated to the Buckley-Leverett problem. The performance of the proposed full finite volume formulation is verified by solving some relevant benchmark problems.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Database with missing values it is an occurrence often found in the real world, beiging of this problem caused by several reasons (equipment failure that transmits and stores the data, handler failure, failure who provides information, etc.). This may make the data inconsistent and unable to be analyzed, leading to very skewed conclusions. This dissertation aims to explore the use of Multilayer Perceptron Artificial Neural Network (ANN MLP), with new activation functions, considering two approaches (single imputation and multiple imputation). First, we propose the use of Maximum Likelihood Estimation Method (MLE) in each network neuron activation function, against the approach currently used, which is without the use of such a method or when is used only in the cost function (network output). It is then analyzed the results of these approaches compared with the Expectation Maximization algorithm (EM) is that the state of the art to treat missing data. The results indicate that when using the Artificial Neural Network MLP with Maximum Likelihood Estimation Method, both in all neurons and only in the output function, lead the an imputation with lower error. These experimental results, evaluated by metrics such as MAE (Mean Absolute Error) and RMSE (Root Mean Square Error), showed that the better results in most experiments occured when using the MLP RNA addressed in this dissertation to single imputation and multiple. / Base de dados com valores faltantes é uma ocorrência frequentemente encontrada no mundo real, sendo as causas deste problema são originadas por motivos diversos (falha no equipamento que transmite e armazena os dados, falha do manipulador, falha de quem fornece a informação, etc.). Tal situação pode tornar os dados inconsistentes e inaptos de serem analisados, conduzindo às conclusões muito enviesadas. Esta dissertação tem como objetivo explorar o emprego de Redes Neurais Artificiais Multilayer Perceptron (RNA MLP), com novas funções de ativação, considerando duas abordagens (imputação única e imputação múltipla). Primeiramente, é proposto o uso do Método de Estimativa de Máxima Verossimilhança (EMV) na função de ativação de cada neurônio da rede, em contrapartida à abordagem utilizada atualmente, que é sem o uso de tal método, ou quando o utiliza é apenas na função de custo (na saída da rede). Em seguida, são analisados os resultados destas abordagens em comparação com o algoritmo Expectation Maximization (EM) que é o estado da arte para tratar dados faltantes. Os resultados obtidos indicam que ao utilizar a Rede Neural Artificial MLP com o Método de Estimativa de Máxima Verossimilhança, tanto em todos os neurônios como apenas na função de saída, conduzem a uma imputação com menor erro. Os resultados experimentais foram avaliados via algumas métricas, sendo as principais o MAE (Mean Absolute Error) e RMSE (Root Mean Square Error), as quais apresentaram melhores resultados na maioria dos experimentos quando se utiliza a RNA MLP abordada neste trabalho para fazer imputação única e múltipla.

This thesis studies why car-initiatives are implemented and how political visions is intertwined in this process. These topics are further explored by looking at how certain critical groups are impacted by car-free initiatives and how they can affect polarization. We use a holistic multiple case comparing Oslo’s Car-free Livability Programme with Living Stockholm. This analysis is structured with our adapted version of the multi-level perspective framework, which emphasizes social components to a greater extent than the original framework. The results show that climate concerns, a common reason to implement car-free initiatives is superseded by softer values such as an increased appreciation of urban areas. Prohibiting cars from city centers has limited short term climate effects. Instead, the value of car-free initiatives is achieved when the urban environment is improved. Additionally, an important and often overlooked result is that car-free initiatives may help change the publics’ perception of the necessity of cars. Furthermore, the political vision behind the project is interlinked with how car-free initiatives are recognized in the public. A strong political vision backed by heavy rhetoric increases the societal impact of the project, as exemplified by Oslo. The project can potentially alter the general perception of the necessity of the car long-term with such an approach but is also exposed to the public’s glare. However, if the project only focuses on a specific area of the city, it may contribute towards polarization and a feeling of discontent within society. In comparison, by implementing an agile approach without a clear political vision as Stockholm did, the project becomes more flexible and reduces unintended consequences. but also has less influence on a national or international level. Furthermore, failing to cater for the needs of critical groups, such as people with disabilities and craftsmen, often results in difficulties and may become a major source of concern within the project. However, these issues can often be identified with improved communication and reduced with small means. To conclude, the emergence of car-free initiatives is a budding trend not only in Scandinavian cities, but around the world. Fueled by concerns about the climate and an urge for citizens to reclaim urban space, car-free initiatives will become more common. Therefore, to implement successful car-free initiatives, it is vital for institutional actors to keep in mind the key points proposed in this thesis, in order to create successful, vibrant cities in the future. / Den här uppsatsen studerar varför bilfria initiativ implementeras och hur den politiska visionen påverkar utformningen. Vi analyserar även hur vissa grupper kan beröras negativt av bilfria initiativ och hur det kan påverka polariseringen i en stad. Uppsatsen använder sig av en holistisk multipel case studie, och jämför de båda huvudstadsinitiativen Bilfritt Byliv i Oslo och Levande Stockholm. Analysen är strukturerad med hjälp av vår anpassade version av multi-level perspective ramverket, som lägger större vikt vid sociala aspekter än ursprungsmodellen. Resultaten visar att klimatförbättringar, en vanlig anledning till att implementera bilfria initiativ, inte är den främsta samhällsnyttan. Andra aspekter som ofta förbises, exempelvis en ökad uppskattning av urbana miljöer, tycks vara viktigare. Att förbjuda bilar har begränsad direkt klimatnytta, utan det är vad stadsytan används till i stället som skapar olika mervärden. En ökad insikt om detta skulle sannolikt kunna göra initiativ för att minska privat bilismen mer ändamålsenliga. Vidare kan bilfria initiativ påverka allmänhetens uppfattning om bilens nödvändighet, vilket är en fråga som inte fångas upp av existerande litteratur. Bilfria initiativs utformning, och allmänhetens uppfattning av det påverkas till stor del av projektets politiska vision. En tydlig vision och kommunikation kan skapa en bred allmän medvetenhet om projektet, som i Oslos fall. Initiativetkan på så sätt skapa en betydande förändring i samhället, men exponeras därigenom även för kritik. Om projektet enbart omfattar särskilda stadsområden finns det en risk för att projektet ökar polariseringen och upplevelsen av utanförskap i staden. Om man i stället använder en mer agil approach utan en tydlig politisk vision, likt Stockholm, blir projektet mer flexibelt och minskar risken för negativa konsekvenser. Men man går därmed till stor del miste om möjligheten att påverka attityder på nationell, eller internationell nivå. Att inte ta hänsyn till grupper med särskilda behov, som äldre eller personer med funktionsnedsättning, resulterar i svårigheter såväl för dessa gruppersom för projektet. Med en intressent analys i förväg och en tydlig kommunikation kan många problem åtgärdas med små medel. Sammanfattningsvis har vi funnit att bilfria initiativ är en trend som växer sig allt starkare runt om i världen, pådriven av en ökad klimatmedvetenhet och en vilja bland stadens invånare att återta urbana miljöer från bilar. Med studien presenterar vi viktiga aspekter för att möjliggöra en effektiv implementering av bilfria initiativ och skapa framtidens levande städer.

Denial of service attacks (DoS) are a common threat to many online services. These attacks aim to overcome the availability of an online service with massive traffic from multiple sources. By spoofing legitimate users, an attacker floods a target system with a high quantity of packets or connections to crash its network resources, bandwidth, equipment, or servers. Packet filtering methods are the most known way to prevent these attacks via identifying and blocking the spoofed attack from reaching its target. In this project, the extent of the DoS attacks problem and attempts to prevent it are explored. The attacks categories and existing countermeasures based on preventing, detecting, and responding are reviewed. Henceforward, a neural network learning algorithms and statistical analysis are utilized into the designing of our proposed packet filtering system.

Im Mittelpunkt dieser Arbeit standen Signaltransduktionsprozesse in den Strukturen der Kraftübertragung quergestreifter Muskelzellen, d. h. in den Costameren (Zell-Matrix-Kontakten) und den Glanzstreifen (Zell-Zell-Kontakten der Kardiomyozyten).<br><br>Es ließ sich zeigen, dass sich die Morphologie der Zell-Matrix-Kontakte während der Differenzierung von Skelettmuskelzellen dramatisch ändert, was mit einer veränderten Proteinzusammensetzung einhergeht. Immunfluoreszenz-Analysen von Skelettmuskelzellen verschiedener Differenzierungsstadien implizieren, dass die Signalwege, welche die Dynamik der Fokalkontakte in Nichtmuskelzellen bestimmen, nur für frühe Stadien der Muskeldifferenzierung Relevanz haben können. Ausgehend von diesem Befund wurde begonnen, noch unbekannte Signalwege zu identifizieren, welche die Ausbildung von Costameren kontrollieren: In den Vorläuferstrukturen der Costamere gelang es, eine transiente Interaktion der Proteine Paxillin und Ponsin zu identifizieren. Biochemische Untersuchungen legen nahe, dass Ponsin über eine Skelettmuskel-spezifische Insertion im Carboxyterminus das Adapterprotein Nck2 in diesen Komplex rekrutiert. Es wird vorgeschlagen, dass die drei Proteine einen ternären Signalkomplex bilden, der die Umbauvorgänge der Zell-Matrix-Kontakte kontrolliert und dessen Aktivität von mitogen activated protein kinases (MAPK) reguliert wird.<br><br>Die Anpassungsvorgänge der Strukturen der Kraftübertragung an pathologische Situtation (Kardiomyopathien) in der adulten quergestreiften Muskulatur wurden ausgehend von einem zweiten Protein, dem muscle LIM protein (MLP), untersucht. Es konnte gezeigt werden, dass ein mutiertes MLP-Protein, das im Menschen eine hypertrophe Kardiomyopathie (HCM) auslöst, strukturelle Defekte aufweist und weniger stabil ist. Weiterhin zeigte dieses mutierte Protein eine verringerte Bindungsfähigkeit an die beiden Liganden N-RAP und alpha-Actinin. Die molekulare Grundlage der HCM-verursachenden Mutationen im MLP-Gen könnte folglich eine Veränderung der Homöostase im ternären Komplex MLP &ndash; N-RAP &ndash; alpha-Actinin sein. Die Expressionsdaten eines neu generierten monoklonalen MLP-Antikörpers deuten darauf hin, dass die Funktionen des MLP nicht nur für die Integrität des Myokards, sondern auch für die der Skelettmuskulatur notwendig sind. / The cell-matrix-contacts (costameres) and cell-cell-contacts (intercalated discs of cardiomyocytes) of cross-striated muscle cells transmit mechanical forces to the exterior. On top of this mechanical function, both structures have been implied to be involved in signal transduction processes.<br><br>Dramatic morphological changes in the overall structure of cell-matrix-contacts of skeletal muscle cells were revealed during differentiation. Moreover, this reorganisation was accompanied by alterations in protein composition. Immunofluorescence microscopy indicated that signalling pathways which control the dynamics of focal contacts in non-muscle cells seem to be important only for early differentiation stages of skeletal muscle cells. To explore novel signalling pathways involved in regulating the formation of costameres, signalling molecules engaged were identified. Thus, paxillin and ponsin transiently interact at the precursors of costameres during muscle development. In addition, biochemical data indicate that a skeletal muscle specific module in the carboxyterminal part of ponsin can recruit the adapter protein Nck2 to this complex. Hence, the three proteins might form a ternary signalling complex involved in controlling the reorganisation of cell-matrix-contacts. Apparently, the activity of this signalling complex is regulated by mitogen activated protein kinases (MAPK).<br><br>A second approach has focussed on adaptational processes of the same structures observed in pathological situations. In particular, the role of muscle LIM protein (MLP) in hypertrophic cardiomyopathy (HCM) was investigated. It was shown that a HCM-causing mutant MLP protein fails to fold properly and that the consequent loss of stability is reflected in altered binding properties: the mutant MLP protein shows decreased binding to both N-RAP and alpha-actinin. Hence, the molecular basis for HCM-causing mutations in the MLP gene might be an altered homeostasis of the ternary complex MLP &ndash; N-RAP &ndash; alpha-actinin. Increasing evidence indicates that the functions of MLP are required not only for the integrity of the myocardium. In addition, MLP seems to have regulatory functions in skeletal muscle tissues.

The present work focuses on the system identification method of aerodynamic parameter estimation which is used to calculate the stability and control derivatives required for aircraft flight mechanics. A new rotorcraft parameter estimation technique is proposed which uses a type of artificial neural network (ANN) called radial basis function network (RBFN). Rotorcraft parameter estimation using ANN is an unexplored research topic and the earlier works in this area have used the output error, equation error and filter error methods which are conventional parameter estimation methods. However, the conventional methods require an accurate non-linear rotorcraft simulation model which is not required by the ANN based method. The application of RBFN overcomes the drawbacks of multilayer perceptron (MLP) based delta method of parameter estimation and gives satisfactory results at either end of the ordered set of estimates. This makes the RBFN based delta method for parameter estimation suitable for rotorcraft studies, as both transition and high speed flight regime characteristics can be studied. The RBFN based delta method for parameter estimation is used for computation of aerodynamic parameters from both simulated and real time flight data. The simulated data is generated from an 8-DoF non-linear simulation model based on the Level-1 criteria of rotorcraft simulation modeling. The generated simulated data is used for computation of the quasi-steady and the time-variant stability and control parameters for different flight conditions using the RBFN based delta method. The performance of RBFN based delta method is also analyzed in the presence of state and measurement noise as well as outliers. The established methodology is then applied to compute parameters directly from real time flight test data for a BO 105 S123 helicopter obtained from DLR (German Aerospace Center). The parameters identified using the RBFN based delta method are compared with the identified values for the BO 105 helicopter from published literature which have used conventional parameter estimation techniques for parameter estimation using a 6-DoF and a 9-DoF rotorcraft simulation model. Finally, the estimated parameters are verified from the flight data generated by a frequency sweep pilot control input for assessing the predictive capability of the RBFN based delta method. Since the approach directly computes the parameters from flight data, it can be used for a reliable description of the higher frequency range, which is needed for high bandwidth flight control and in-flight simulation.

Dans l’industrie de fabrication mécanique et notamment pour l’utilisation des centres d’usinage haute vitesse, la connaissance des propriétés dynamiques du système broche-outil-pièce en opération est d’une grande importance. L’accroissement des performances des machines-outils et des outils de coupe a œuvré au développement de ce procédé compétitif. D’innombrables travaux ont été menés pour accroître les performances et les remarquables avancées dans les matériaux, les revêtements des outils coupants et les lubrifiants ont permis d’accroître considérablement les vitesses de coupe tout en améliorant la qualité de la surface usinée. Cependant, l’utilisation rationnelle de cette technologie est encore fortement pénalisée par les lacunes dans la connaissance de la coupe, que ce soit au niveau microscopique des interactions fines entre l’outil et la matière coupée, aussi bien qu’au niveau macroscopique intégrant le comportement de la cellule élémentaire d’usinage, si bien que le comportement dynamique en coupe garde encore une grande part de questionnement et exige de l’utilisateur un bon niveau de savoir-faire et parfois d’empirisme pour exploiter au mieux les capacités des moyens de production. Le fonctionnement des machines d’usinage engendre des vibrations qui sont souvent la cause des dysfonctionnements et accélère l’usure des composantes mécaniques (roulements) et outils. Ces vibrations sont une image des efforts internes des systèmes, d’où l’intérêt d’analyser les grandeurs mécaniques vibratoires telle que la vitesse ou l’accélération vibratoire. Ces outils sont indispensables pour une maintenance moderne dont l’objectif est de réduire les coûts liés aux pannes / In machining field, chatter phenomenon takes a lot of interest because manufacturing enterprises are turning to the automation system and the development of reliable and robust monitoring system to provide increased productivity, improved part quality and reduced costs. Chatter occurrence has several negatives effects: a) Poor surface quality, b) Unacceptable inaccuracy, c) Excessive noise, d) Machine tool damage, e) Reduced material removal rate, f) Increase costs in terms of production time, g) Waste of material, h) Environmental impact in terms of materials and energy. Moreover, chatter monitoring is not an easy task for various reasons. Firstly, the non linearity of machining processes and the time-varying of systems complicate this task. Secondly, the sensitivity and the dependency of acquired signals from sensors on different factors, such as machining condition, cutting tool geometry and workpiece material. Thirdly, at high rotating speeds, the gyroscopic effects on the spindle dynamics in addition to the centrifugal force on the bearings and thermal effects become more relevant thus affecting the stability of the system. For these reasons, demands for an advanced automatic chatter detection and monitoring system for optimizing and controlling machining processes becomes a topic of enormous interest. Several researches in this field are performed. Advanced monitoring and detection methods are developed mostly relying on time, frequency and time-frequency analysis. In order to detect chatter in milling centers, three new methods are studied and developed using advanced techniques of signal processing and exploiting cyclostationarity property of signals acquired

This thesis deals with classification of different types of time courses of ECG signals. Main objective was to recognize the normal cycles and several forms of arrhythmia and to classify the exact types of them. Classification has been done with usage of algorithms of Neural Networks in Matlab program, with its add-on (Neural Network Toolbox). The result of this thesis is application, which makes possible to load an ECG signal, pre-process it and classify its each cycle into five classes. Percentage results of this classification are in the conclusion of this thesis.

Research questions:  How can the Aspvik model be useful for the traditionally functioning water and sewage industry? What are the main challenges for regime actors to implement systems similar to those derived from the Aspvik model? Purpose: The purpose of the study is two-fold. Firstly, we intend to investigate system development and entrepreneurship from below in a local project in the water and sewage industry and its business model. Secondly, the study aims to provide an understanding of how the organization and the development process differ between the local Aspvik project and the existing regime within the water and sewage industry. Method: The study was of a qualitative nature based on an abductive approach. The theoretical framework was based on scientific articles and publications as well as books. The empirical data collection consisted of the collection of primary and secondary data, of which primary data was obtained through a total of 13 semi-structured interviews and secondary data via web pages, public print (laws and regulations) and other sources. A thematic analysis was performed based on the theoretical framework and the empirical data. Conclusion: The Aspvik model can generate usefulness as it contributes by providing a businesslike approach with transparency and visualization of what opportunities the industry actors have and what it may cost. With transparency, the current problems and bottlenecks in the industry became more evident. There are major environmental benefits in increasing the rate of development of the municipal water and sewage grid. It is mainly the Water Services Act, section 6 in particular, which is the main challenge for achieving a more efficient expansion of the water and sewage grid, both in terms of resources and time. It may require organizational change at the regime level, this in order to handle several projects simultaneously, or to provide increased support for private initiatives similar to the Aspvik project. / Problemställning: Hur kan Aspviksmodellen generera nytta för den traditionellt fungerande VA-branschen? Vilka är de huvudsakliga utmaningarna för regimaktörer att implementera system liknande det som härrör från Aspviksmodellen? Syfte: Studiens syfte är tvådelat. För det första ämnar vi undersöka systemuppbyggnad och entreprenörskap från grunden i ett lokalt VA- projekt och dess affärsmodell. För det andra syftar studien till att ge förståelse för hur organisationen och VA-utbyggnadsprocessen skiljer sig mellan det lokala VA-projektet och den befintliga regimen. Metod: Studien var av kvalitativ karaktär med utgångspunkt i en abduktiv ansats. Den teoretiska referensramen var baserad på vetenskapliga publikationer och böcker samt studentlitteratur. Den empiriska datainsamlingen utgjordes av insamling av primära och sekundära data, varav primärdata erhållits genom totalt 13 semistrukturerade intervjuer och sekundärdata via webbsidor, offentligt tryck (lagar och förordningar) och övriga källor. Utifrån den teoretiska referensramen och den empiriska data genomfördes en tematisk analys. Slutsats: Aspviksmodellen kan generera nytta då den bidrar med att tillhandahålla en affärsmässig strategi med ökad transparens och visualisering över vilka möjligheter branschaktörer har och vad det kan kosta. Med transparens blev rådande problem och flaskhalsar i branschen mer tydliga. Det finns stora miljömässiga fördelar med att öka utbyggnadstakten av det kommunala VA-nätet. Från regimens synvinkel är det huvudsakligen vattentjänstlagen i sig, 6 § i synnerhet som utgör en utmaning mot en effektivare utbyggnad av VA-nätet, både ekonomiskt och tidsmässigt. För att hantera det krävs någon organisatorisk förändring på regimnivå för att kunna hantera flera projekt samtidigt, alternativt att från regimens sida ge ett ökat stöd till privata initiativ i samma slag som Aspviksprojektet.