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Robust On-Line Frequency Identification for a SinusoidFUKUDA, Toshio, ZHAI, Guisheng, CHEN, Xinkai 01 November 2006 (has links)
No description available.
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Método adaptativo para a interpretação de medições oriundas de sistemas elétricos. / Adaptive method for the interpretation of measurements from electrical systems.Nicoli, Sidnei 05 May 2017 (has links)
Esta pesquisa aborda um método adaptativo baseado em regras e aplicado a de informação não supervisionados de fluxo contínuo com a utilização de técnicas inteligentes, utilizando séries históricas de medições. O objetivo principal é identificar medições que podem ser categorizadas de diversas formas, tais como novidades, outliers, anomalias, dentre outras, apesar do método apresentado abordar somente monitoramento e autonomia, o mesmo pode ser utilizado para controle de ações desde que esteja integrado aos dispositivos de campo necessários para atuação de um processo. Para tanto, utiliza uma representação do conhecimento adequada, critérios de busca inteligente, inferência e critérios para a aprendizagem, possibilitando um processo de melhoria contínua. Os estudos realizados com medições possibilitaram ao estabelecimento de processos que conduziram ao surgimento de um Método Adaptativo para a Interpretação de Medições aplicável a sistemas inteligentes e do Método Complementar, capaz de auxiliar na interpretação de resultados obtidos por outros métodos já estabelecidos para identificação de anomalias. Para esse fim, foram consideradas: uma técnica adaptativa, a importância do ambiente de influência relativo ao ponto de medição e a utilização das novidades como referência às mudanças que ocorrem em um ambiente. / This research addresses a rules-based adaptive method applied to unsupervised continuous flow information systems using intelligent techniques using historical series of measurements. The main goal is to identify measurements that can be categorized in different ways, such as novelties, outliers, anomalies, among others, although the presented method only approach monitoring and autonomy, it can be used to control actions since it is integrated with the devices required to perform a process control. To do so, it uses a representation of adequate knowledge, intelligent search criteria, inference and criteria for learning, enabling a process of continuous improvement. The research conducted with real measurements allowed the development of optimized computational routines that guided the development of a new method based on adaptive techniques for measurements interpretation and the Complementary Method, able to assist the interpretation of results obtained by other methods already established to identify non-standard. To this end, we considered: an adaptive technique, the importance of the influence environment relative to the measurement point and the use of the novelties as a reference to the changes that occur in an environment.
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Coupling of time integration schemes for compressible unsteady flowsMuscat, Laurent 12 March 2019 (has links) (PDF)
This work deals with the design of a hybrid time integrator that couples spatially explicit and implicit time integrators. In order to cope with the industrial solver of Ariane Group called FLUSEPA, the explicit scheme of Heun and the implicit scheme of Crank-Nicolson are hybridized using the transition parameter : the whole technique is called AION time integration. The latter is studied into details with special focus on spectral behaviour and on its ability to keep the accuracy. It is shown that the hybrid technique has interesting dissipation and dispersion properties while maintaining precision and avoiding spurious waves. Moreover, this hybrid approach is validated on several academic test cases for both convective and diffusive fluxes. And as expected the method is more interesting in term of computational time than standard time integrators. For the extension of this hybrid approach to the temporal adaptive method implemented in FLUSEPA, it was necessary to improve some treatments in order to maintain conservation and acceptable spectral properties. Finally the hybrid time integration was also applied to a RANS/LES turbulent test case with interesting computational time while capturing the flow physics.
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Modellierung und Numerik wachsender Risse bei piezoelektrischem Material / Modeling and Numerics of Propagating Cracks in Piezoelectric MaterialMeyer, Arnd, Steinhorst, Peter 02 November 2010 (has links) (PDF)
Zur numerischen Simulation piezoelektrischer Probleme mit linearem Materialgesetz wird die adaptive Finite-Element-Methode genutzt. Bei der Lösung der entstehenden Gleichungssysteme vom Sattelpunktstyp wird auf eine Variante des Bramble-Pasciak-CG zurückgegriffen. Die Einbettung von Projektionstechniken in den Löser erlaubt eine Behandlung von verschiedenen Problembesonderheiten, speziell wird hier auf die Fälle konstanten Potentials auf Teilrändern sowie Kontaktprobleme an wachsenden Rissen eingegangen. Erste numerische Ergebnisse werden an einigen Beispielen demonstriert.
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Método adaptativo para a interpretação de medições oriundas de sistemas elétricos. / Adaptive method for the interpretation of measurements from electrical systems.Sidnei Nicoli 05 May 2017 (has links)
Esta pesquisa aborda um método adaptativo baseado em regras e aplicado a de informação não supervisionados de fluxo contínuo com a utilização de técnicas inteligentes, utilizando séries históricas de medições. O objetivo principal é identificar medições que podem ser categorizadas de diversas formas, tais como novidades, outliers, anomalias, dentre outras, apesar do método apresentado abordar somente monitoramento e autonomia, o mesmo pode ser utilizado para controle de ações desde que esteja integrado aos dispositivos de campo necessários para atuação de um processo. Para tanto, utiliza uma representação do conhecimento adequada, critérios de busca inteligente, inferência e critérios para a aprendizagem, possibilitando um processo de melhoria contínua. Os estudos realizados com medições possibilitaram ao estabelecimento de processos que conduziram ao surgimento de um Método Adaptativo para a Interpretação de Medições aplicável a sistemas inteligentes e do Método Complementar, capaz de auxiliar na interpretação de resultados obtidos por outros métodos já estabelecidos para identificação de anomalias. Para esse fim, foram consideradas: uma técnica adaptativa, a importância do ambiente de influência relativo ao ponto de medição e a utilização das novidades como referência às mudanças que ocorrem em um ambiente. / This research addresses a rules-based adaptive method applied to unsupervised continuous flow information systems using intelligent techniques using historical series of measurements. The main goal is to identify measurements that can be categorized in different ways, such as novelties, outliers, anomalies, among others, although the presented method only approach monitoring and autonomy, it can be used to control actions since it is integrated with the devices required to perform a process control. To do so, it uses a representation of adequate knowledge, intelligent search criteria, inference and criteria for learning, enabling a process of continuous improvement. The research conducted with real measurements allowed the development of optimized computational routines that guided the development of a new method based on adaptive techniques for measurements interpretation and the Complementary Method, able to assist the interpretation of results obtained by other methods already established to identify non-standard. To this end, we considered: an adaptive technique, the importance of the influence environment relative to the measurement point and the use of the novelties as a reference to the changes that occur in an environment.
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Multi-trait Analysis of Genome-wide Association Studies using Adaptive Fisher's MethodDeng, Qiaolan 27 September 2022 (has links)
No description available.
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Automatic Sampling with the Ratio-of-uniforms MethodLeydold, Josef January 1999 (has links) (PDF)
Applying the ratio-of-uniforms method for generating random variates results in very efficient, fast and easy to implement algorithms. However parameters for every particular type of density must be precalculated analytically. In this paper we show, that the ratio-of-uniforms method is also useful for the design of a black-box algorithm suitable for a large class of distributions, including all with log-concave densities. Using polygonal envelopes and squeezes results in an algorithm that is extremely fast. In opposition to any other ratio-of-uniforms algorithm the expected number of uniform random numbers is less than two. Furthermore we show that this method is in some sense equivalent to transformed density rejection. (author's abstract) / Series: Preprint Series / Department of Applied Statistics and Data Processing
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Modellierung und Numerik wachsender Risse bei piezoelektrischem MaterialMeyer, Arnd, Steinhorst, Peter 02 November 2010 (has links)
Zur numerischen Simulation piezoelektrischer Probleme mit linearem Materialgesetz wird die adaptive Finite-Element-Methode genutzt. Bei der Lösung der entstehenden Gleichungssysteme vom Sattelpunktstyp wird auf eine Variante des Bramble-Pasciak-CG zurückgegriffen. Die Einbettung von Projektionstechniken in den Löser erlaubt eine Behandlung von verschiedenen Problembesonderheiten, speziell wird hier auf die Fälle konstanten Potentials auf Teilrändern sowie Kontaktprobleme an wachsenden Rissen eingegangen. Erste numerische Ergebnisse werden an einigen Beispielen demonstriert.:1 Einführung
1.1 Problembeschreibung Piezoelektrizität
1.2 Abgeleitete Größen, Materialgesetz, Gleichungen
1.3 Bilinearformen, schwache Formulierung
2 Implementierung
2.1 Sattelpunktsproblem
2.2 FE-Formulierung
2.3 Löser und Vorkonditionierung
2.4 Adaptivität
3 Besonderheiten von Randbedingungen
3.1 Konstantes Potential auf Teilrändern
3.2 Rissproblem
4 Rissschließen und Kontaktproblem
4.1 Motivation für Risskontaktbetrachtung
4.2 Bezeichnungen
4.3 Kontaktproblem für Verschiebung und Behandlung des Potentials
4.4 FEM-Implementierung des Risskontaktes
4.5 Numerische Beispiele
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\"Simulações de escoamentos tridimensionais bifásicos empregando métodos adaptativos e modelos de campo fase\" / \"Simulations of 3D two-phase flows using adaptive methods and phase field models\"Nós, Rudimar Luiz 20 March 2007 (has links)
Este é o primeiro trabalho que apresenta simulações tridimensionais completamente adaptativas de um modelo de campo de fase para um fluido incompressível com densidade de massa constante e viscosidade variável, conhecido como Modelo H. Solucionando numericamente as equações desse modelo em malhas refinadas localmente com a técnica AMR, simulamos computacionalmente escoamentos bifásicos tridimensionais. Os modelos de campo de fase oferecem uma aproximação física sistemática para investigar fenômenos que envolvem sistemas multifásicos complexos, tais como fluidos com camadas de mistura, a separação de fases sob forças de cisalhamento e a evolução de micro-estruturas durante processos de solidificação. Como as interfaces são substituídas por delgadas regiões de transição (interfaces difusivas), as simulações de campo de fase requerem muita resolução nessas regiões para capturar corretamente a física do problema em estudo. Porém essa não é uma tarefa fácil de ser executada numericamente. As equações que caracterizam o modelo de campo de fase contêm derivadas de ordem elevada e intrincados termos não lineares, o que exige uma estratégia numérica eficiente capaz de fornecer precisão tanto no tempo quanto no espaço, especialmente em três dimensões. Para obter a resolução exigida no tempo, usamos uma discretização semi-implícita de segunda ordem para solucionar as equações acopladas de Cahn-Hilliard e Navier-Stokes (Modelo H). Para resolver adequadamente as escalas físicas relevantes no espaço, utilizamos malhas refinadas localmente que se adaptam dinamicamente para recobrir as regiões de interesse do escoamento, como por exemplo, as vizinhanças das interfaces do fluido. Demonstramos a eficiência e a robustez de nossa metodologia com simulações que incluem a separação dos componentes de uma mistura bifásica, a deformação de gotas sob cisalhamento e as instabilidades de Kelvin-Helmholtz. / This is the first work that introduces 3D fully adaptive simulations for a phase field model of an incompressible fluid with matched densities and variable viscosity, known as Model H. Solving numerically the equations of this model in meshes locally refined with AMR technique, we simulate computationally tridimensional two-phase flows. Phase field models offer a systematic physical approach to investigate complex multiphase systems phenomena such as fluid mixing layers, phase separation under shear and microstructure evolution during solidification processes. As interfaces are replaced by thin transition regions (diffuse interfaces), phase field simulations need great resolution in these regions to capture correctly the physics of the studied problem. However, this is not an easy task to do numerically. Phase field model equations have high order derivatives and intricate nonlinear terms, which require an efficient numerical strategy that can achieve accuracy both in time and in space, especially in three dimensions. To obtain the required resolution in time, we employ a semi-implicit second order discretization scheme to solve the coupled Cahn-Hilliard/Navier-Stokes equations (Model H). To resolve adequatly the relevant physical scales in space, we use locally refined meshes which adapt dynamically to cover special flow regions, e.g., the vicinity of the fluid interfaces. We demonstrate the efficiency and robustness of our methodology with simulations that include spinodal decomposition, the deformation of drops under shear and Kelvin-Helmholtz instabilities.
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Coupling of time integration schemes for compressible unsteady flows / Couplage de schémas temporels pour la simulation des écoulements compressibles instationnairesMuscat, Laurent 12 March 2019 (has links)
Dans ce travail, on s'intéresse au développement d'une méthode hybride qui couple spatialement les schémas d'intégration temporelle explicite et implicite. Afin de répondre aux contraintes du solveur industriel FLUSEPA, les schémas explicite Heun et implicite Crank-Nicolson ont été hybridés via un paramètre de transition : l'approche mise en place est appelée schéma AION. Cette dernière est étudiée en détails avec une attention particulière sur son comportement spectral et sa capacité à maintenir l'ordre de précision. On montre que le traitement hybride a d'intéressants comportements dissipatif et dispersif tout en empêchant la réflexion d'ondes parasites et en maintenant la précision attendue. De plus, l'approche hybride est validée sur plusieurs cas académiques à la fois pour les flux convectifs et pour les flux diffusifs. Et comme espéré, la méthode est plus intéressante en terme de temps de calcul que les méthodes standards d'intégration temporelle. Pour l'extension de cette approche à la méthode temporelle adaptative présente dans FLUSEPA, il a été nécessaire d'améliorer le traitement qui permet à la méthode d’être conservative tout en obtenant des propriétés spectrales acceptables. Finalement l'approche hybride a été aussi étendue pour la modélisation RANS/LES de la turbulence avec des temps de calcul intéressants tout en capturant la physique de l'écoulement / This work deals with the design of a hybrid time integrator that couples spatially explicit and implicit time integrators. In order to cope with the industrial solver of Ariane Group called FLUSEPA, the explicit scheme of Heun and the implicit scheme of Crank-Nicolson are hybridized using the transition parameter : the whole technique is called AION time integration. The latter is studied into details with special focus on spectral behaviour and on its ability to keep the accuracy. It is shown that the hybrid technique has interesting dissipation and dispersion properties while maintaining precision and avoiding spurious waves. Moreover, this hybrid approach is validated on several academic test cases for both convective and diffusive fluxes. And as expected the method is more interesting in term of computational time than standard time integrators. For the extension of this hybrid approach to the temporal adaptive method implemented in FLUSEPA, it was necessary to improve some treatments in order to maintain conservation and acceptable spectral properties. Finally the hybrid time integration was also applied to a RANS/LES turbulent test case with interesting computational time while capturing the flow physics.
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