Modélisation des machines par circuits couplés pour l’observation des courants de barres au rotor

Ce travail présente une modélisation rapide d’ordre élévé capable de modéliser une configuration rotorique en cage complète ou en grille, de reproduire les courants de barre et tenir compte des harmoniques d’espace. Le modèle utilise une approche combinée d’éléments finis avec les circuits-couplés. En effet, le calcul des inductances est réalisé avec les éléments finis, ce qui confère une précision avancée au modèle. Cette méthode offre un gain important en temps de calcul sur les éléments finis pour des simulations transitoires. Deux outils de simulation sont développés, un dans le domaine du temps pour des résolutions dynamiques et un autre dans le domaine des phaseurs dont une application sur des tests de réponse en fréquence à l’arrêt (SSFR) est également présentée. La méthode de construction du modèle est décrite en détail de même que la procédure de modélisation de la cage du rotor. Le modèle est validé par l’étude de machines synchrones: une machine de laboratoire de 5.4 KVA et un grand alternateur de 109 MVA dont les mesures expérimentales sont comparées aux résultats de simulation du modèle pour des essais tels que des tests à vide, des courts-circuits triphasés, biphasés et un test en charge.

Statistical modeling of protein lysate array data

The protein lysate array is an emerging technology for quantifying the protein concentration ratios in multiple biological samples. It is gaining popularity, and has the potential to answer questions about post-translational modifications and protein pathway relationships. Statistical inference for a parametric quantification procedure has been inadequately addressed in the literature, mainly due to two challenges: the increasing dimension of the parameter space and the need to account for dependence in the data. Each chapter of this thesis addresses one of these issues. In Chapter 1, an introduction to the protein lysate array quantification is presented, followed by the motivations and goals for this thesis work. In Chapter 2, we develop a multi-step procedure for the Sigmoidal models, ensuring consistent estimation of the concentration level with full asymptotic efficiency. The results obtained in this chapter justify inferential procedures based on large-sample approximations. Simulation studies and real data analysis are used to illustrate the performance of the proposed method in finite-samples. The multi-step procedure is simpler in both theory and computation than the single-step least squares method that has been used in current practice. In Chapter 3, we introduce a new model to account for the dependence structure of the errors by a nonlinear mixed effects model. We consider a method to approximate the maximum likelihood estimator of all the parameters. Using the simulation studies on various error structures, we show that for data with non-i.i.d. errors the proposed method leads to more accurate estimates and better confidence intervals than the existing single-step least squares method.

Analysis of β-tricalcium phosphate granules prepared with different formulations by nano-computed tomography and scanning electron microscopy

International audience

The use of animal models in multiple myeloma

International audience

EL "PASS THROUGH" DEL TIPO DE CAMBIO EN LOS PRECIOS DE BIENES TRANSABLES Y NO TRANSABLES EN COSTA RICA

Este trabajo estima el coeficiente de pass through del tipo de cambio en los precios de bienes transables y no transables en Costa Rica, para el corto y el largo plazo. Se utiliza el análisis de mínimos cuadrados para estimar los coeficientes, y se explora la dinámica de ajuste de los modelos utilizando el análisis de vectores auto regresivo. Dentro de los principales resultados del modelo se encontró un coeficiente de pass through para los bienes transables de 13% en el corto plazo y de 68% en el largo plazo; para los bienes no transables, el pass through es de 10% y 52% en el corto y largo plazo respectivamente. En el largo plazo se incluye un 7% de pass through indirecto producto del efecto de los precios de los transables en los de no transables. El estudio de la dinámica de ajuste de los precios de transables y no transables ante un choque del tipo de cambio mostró una duración de 17 y 27 meses respectivamente. Además se realizaron pruebas de causalidad de Granger y estabilidad del modelo. La primera mostró una relación de precedencia entre las variaciones de tipo de cambio e inflación, y entre inflación de los transables y de los no transables. La segunda evidencia un cambio estructural en el modelo de los no transables entre fines de 1995 e inicio de 1996. AbstractThis paper estimates short run and long run coefficients of exchange rate pass through in to the prices of tradable and non tradable goods in Costa Rica. The coefficients are estimated by OLS. A VAR analysis is conducted in order to estimate the dynamic process between exchange rate and inflation. Granger causality test and a stability test are conducted too. The short run pass through coefficients are 13% and 10%, for tradable and non tradable goods respectively and the long run coefficients are 68% and 52% in the same order. There is a second stage pass through of 7% included in the long run coefficient for non tradable goods. The dynamic analysis shows that the adjustment process of prices as a result of an exchange rate shock takes 17 months for tradable goods and 27 months for non tradable goods. The Granger causality test shows precedence between variation in the exchange rate and inflation, and between the prices of tradable and non tradable goods. There is statistical evidence of a structural change in the non tradable model between the end of 1995 and the beginning of 1996.

Fitting phase type distribution to service process with sequential phases

The work of this thesis is concerned with fitting Hypo-exponential and Erlang phase type distributions for modeling real life processes with non-exponential service time. There exist situations where exponential distributions cannot explain the distribution of service time properly. This thesis presents the application of two traditional statistical estimation techniques to approximate the service distributions of processes with coefficient of variation less than one. It also presents an algorithm to fit Hypo-exponential distribution for complex situations which can’t be handled properly with traditional estimation techniques. The result shows the effect of variation of sample size and other parameters on the efficiency of the estimation techniques by comparing their respective outputs. Furthermore it checks how accurately the proposed algorithm approximates a given distribution.

Probabilistic methods for seasonal forecasting in a changing climate: Cox-type regression models.

For climate risk management, cumulative distribution functions (CDFs) are an important source of information. They are ideally suited to compare probabilistic forecasts of primary (e.g. rainfall) or secondary data (e.g. crop yields). Summarised as CDFs, such forecasts allow an easy quantitative assessment of possible, alternative actions. Although the degree of uncertainty associated with CDF estimation could influence decisions, such information is rarely provided. Hence, we propose Cox-type regression models (CRMs) as a statistical framework for making inferences on CDFs in climate science. CRMs were designed for modelling probability distributions rather than just mean or median values. This makes the approach appealing for risk assessments where probabilities of extremes are often more informative than central tendency measures. CRMs are semi-parametric approaches originally designed for modelling risks arising from time-to-event data. Here we extend this original concept beyond time-dependent measures to other variables of interest. We also provide tools for estimating CDFs and surrounding uncertainty envelopes from empirical data. These statistical techniques intrinsically account for non-stationarities in time series that might be the result of climate change. This feature makes CRMs attractive candidates to investigate the feasibility of developing rigorous global circulation model (GCM)-CRM interfaces for provision of user-relevant forecasts. To demonstrate the applicability of CRMs, we present two examples for El Ni ? no/Southern Oscillation (ENSO)-based forecasts: the onset date of the wet season (Cairns, Australia) and total wet season rainfall (Quixeramobim, Brazil). This study emphasises the methodological aspects of CRMs rather than discussing merits or limitations of the ENSO-based predictors.

Ladrillos elaborados con plástico reciclado (PET), para mampostería no portante

En el presente trabajo se investigó el uso de plástico reciclado para la fabricación de ladrillos para construcción de mampostería no portante. En primer lugar se realiza la caracterización de los residuos sólidos que se generan en la ciudad de Cuenca, donde el 22,7% del total recolectado es material plástico, que se desechan libremente sin un tratamiento previo. De la misma manera se investigan las características del plástico, Polientilen Tereftalato (PET) para descartar efectos nocivos al momento de incluirlos en la mezcla con los materiales tradicionales como son el cemento y agua, agregado fino. Se elaboraron ladrillos con dimensiones de 20x10x6cm con adición de PET al 10, 25, 40, 55, 65 y 70% en sustitución del árido fino. Luego se efectuó diversos ensayoscon la finalidad de compararlos con los ladrillos de arcilla cocida de uso común en la región y analizar el material para mampostería no portante según los lineamientos establecidos por las Normas Ecuatorianas. Una vez realizados los ensayos y analizada la información se obtuvo como resultado un ladrillo óptimo con 25% de adición de PET. El cual fue sometido a un análisis térmico mediante una simulación en el programa Desingnbuilder, obteniendo como resultado niveles de confort término de mejor calidad en viviendas.

Guía didáctica para el uso de la calculadora Casio fx-7400GII en la gráfica de funciones racionales y radicales

El presente trabajo fue realizado con el propósito de relacionar los contenidos de funciones racionales y radicales con los recursos tecnológicos, de manera que éstas se conviertan en formas innovadoras de enseñar y aprender. Para ello se ha propuesto elaborar una guía didáctica sobre el uso de la calculadora Casio fx-7400GII en la gráfica y análisis de funciones racionales y radicales. En ésta propuesta, la calculadora es vista como un recurso didáctico, orientado a promover una metodología constructivista en el proceso de enseñanza-aprendizaje en el mencionado tema. La presente propuesta se debe a que en la educación actual no se están utilizando los recursos tecnológicos como es el caso de la calculadora gráfica en el aula de clase, pues no se disponen de guías didácticassencillas adecuados para una determinada asignatura. Es importante usar la calculadora gráfica en el estudio de las funciones racionales y radicales ya que al momento de realizar su estudio y análisis de forma manual se requiere de mucho tiempo y se convierte en una actividad tediosa, en tanto que se puede ahorrar tiempo y esfuerzo utilizando la calculadora Con la presente propuesta se pretende que los estudiantes alcancen un mejor nivel de conocimiento en el tema, a través del uso de la guía en el aula de clases generando un proceso de enseñanza-aprendizaje más práctico y dinámico

A real time electromagnetic analysis of electric machines for educational purposes and laboratory implementation

This thesis presents a system for visually analyzing the electromagnetic fields of the electrical machines in the energy conversion laboratory. The system basically utilizes the finite element method to achieve a real-time effect in the analysis of electrical machines during hands-on experimentation. The system developed is a tool to support the student's understanding of the electromagnetic field by calculating performance measures and operational concepts pertaining to the practical study of electrical machines. Energy conversion courses are fundamental in electrical engineering. The laboratory is conducted oriented to facilitate the practical application of the theory presented in class, enabling the student to use electromagnetic field solutions obtained numerically to calculate performance measures and operating characteristics. Laboratory experiments are utilized to help the students understand the electromagnetic concepts by the use of this visual and interactive analysis system. In this system, this understanding is accomplished while hands-on experimentation takes place in real-time.

Volatility transmission between stock and exchange-rate markets: A connectedness analysis

This paper empirically investigates volatility transmission among stock and foreign exchange markets in seven major world economies during the period July 1988 to January 2015. To this end, we first perform a static and dynamic analysis to measure the total volatility connectedness in the entire period (the system-wide approach) using a framework recently proposed by Diebold and Yilmaz (2014). Second, we make use of a dynamic analysis to evaluate the net directional connectedness for each market. To gain further insights, we examine the time-varying behaviour of net pair-wise directional connectedness during the financial turmoil periods experienced in the sample period Our results suggest that slightly more than half of the total variance of the forecast errors is explained by shocks across markets rather than by idiosyncratic shocks. Furthermore, we find that volatility connectedness varies over time, with a surge during periods of increasing economic and financial instability.

Improving the Performance of Database-Centric Applications Through Program Analysis

Thesis (Ph.D, Computing) -- Queen's University, 2016-09-30 09:55:51.506

Cavotricuspid isthmus: anatomy and electrophysiology features: its evaluation before radiofrequency ablation

The cavotricuspid isthmus (CTI) in the lower pan of the right atrium, between the inferior caval vein and the tricuspid valve, is considered crucial in producing a conduction delay and. hence, favoring the perpetuation of a reentrant circuit. Non-uniform wall thickness, muscle fiber orientation and the marked variability in muscular architecture in the CTI should be taken into consideration from the perspective of anisotropic conduction, thus producing an electrophysiologic isthmus. The purpose of this article is to review the anatomy and electrophysiology of the CTI in human hearts to provide useful information to plan CTI radio frequency ablation for the patients with atrial flutter.

Review of vibration-based damage detection and condition assessment of bridge structures using structural health monitoring

As a part of vital infrastructure and transportation networks, bridge structures must function safely at all times. However, due to heavier and faster moving vehicular loads and function adjustment, such as Busway accommodation, many bridges are now operating at an overload beyond their design capacity. Additionally, the huge renovation and replacement costs always make the infrastructure owners difficult to undertake. Structural health monitoring (SHM) is set to assess condition and foresee probable failures of designated bridge(s), so as to monitor the structural health of the bridges. The SHM systems proposed recently are incorporated with Vibration-Based Damage Detection (VBDD) techniques, Statistical Methods and Signal processing techniques and have been regarded as efficient and economical ways to solve the problem. The recent development in damage detection and condition assessment techniques based on VBDD and statistical methods are reviewed. The VBDD methods based on changes in natural frequencies, curvature/strain modes, modal strain energy (MSE) dynamic flexibility, artificial neural networks (ANN) before and after damage and other signal processing methods like Wavelet techniques and empirical mode decomposition (EMD) / Hilbert spectrum methods are discussed here.

Semi-active control for structural vibration based on predictive algorithm [Chinese title = 基于预测算法的结构振动半主动控制]

Based on Newmark-β method, a structural vibration response is predicted. Through finding the appropriate control force parameters within certain ranges to optimize the objective function, the predictive control of the structural vibration is achieved. At the same time, the numerical simulation analysis of a two-storey frame structure with magneto-rheological (MR) dampers under earthquake records is carried out, and the parameter influence on structural vibration reduction is discussed. The results demonstrate that the semi-active control based on Newmark-β predictive algorithm is better than the classical control strategy based on full-state feedback control and has remarkable advantages of structural vibration reduction and control robustness.