Neste trabalho o teste de dispositivos analógicos programáveis é abordado. Diversas metodologias de teste analógico existentes são estudadas e algumas delas são utilizadas nas estratégias desenvolvidas. Dois FPAAs (Field Programmable Analog Arrays) comerciais de fabricantes e modelos distintos são utilizados para validar as estratégias de teste propostas. O primeiro dispositivo estudado é um FPAA de tempo contínuo (capaz de implementar circuitos contínuos no tempo) da Lattice Semiconductors. Tal dispositivo é marcado pela característica estrutural de sua programabilidade. Por esta razão, a estratégia a ele aplicada é baseada em um método de teste também estrutural, conhecido como OBT (Oscillation-Based Test). Neste método o circuito é dividido em blocos simples que são transformados em osciladores. Os parâmetros do sinal obtido, tais como a freqüência de oscilação e a amplitude, têm relação direta com os componentes utilizados na implementação do oscilador. Desta maneira, é possível detectar falhas no FPAA observando os parâmetros do sinal gerado. Esta estratégia é estudada inicialmente considerando uma análise externa dos parâmetros do sinal. Como uma alternativa de redução de custos e melhoria na cobertura de falhas, um analisador de resposta baseado em um duplo integrador é adotado, permitindo que a avaliação do sinal gerado pelo oscilador seja feita internamente, utilizando-se os recursos programáveis do próprio FPAA. Os resultados obtidos para as análises interna e externa são então comparados. O segundo FPAA estudado, da Anadigm Company, é um dispositivo a capacitores chaveados que tem como característica a programabilidade funcional. Por esta razão o desenvolvimento de uma técnica de teste estrutural é dificultado, pois não se conhece detalhes da arquitetura do componente. Por esta razão, uma técnica de teste funcional, conhecida como Transient Response Analysis Method, é aplicada ao teste deste FPAA. Neste método o circuito sob teste é dividido em blocos funcionais de primeira e segunda ordem e a resposta transiente destes blocos para um dado estímulo de entrada é analisada. O bloco sob teste é então duplicado e um esquema de auto-teste integrado baseado em redundância é desenvolvido, com o intuito de se obter um sinal de erro. Este sinal de erro representa a diferença das respostas transientes dos blocos duplicados. Como proposta para se aumentar a observabilidade do sinal de erro o mesmo é integrado ao longo tempo, aumentando a capacidade de detecção de falhas quando utilizado este método. Em ambas estratégias o objetivo principal do trabalho é testar os blocos analógicos programáveis dos FPAAs explorando ao máximo a programabilidade dos dispositivos e utilizando recursos pré-existentes para auxiliar no teste. Os resultados obtidos mostram que as estratégias desenvolvidas configuram boas alternativas para o auto-teste integrado deste tipo de componente. / This work addresses the test of programmable analog devices. Several analog test methodologies are studied and some of them are applied in the developed strategies. In order to validate these strategies, two commercial FPAAs (Field Programmable Analog Arrays), of different vendors and distinct models, are considered as devices under test. The first studied device is a continuous-time FPAA from Lattice Semiconductors. One important characteristic of such device is the structural programmability. For this reason the test strategy applied to this FPAA is based in a structural method known as OBT (Oscillation-Based Test). In this method, blocks of the circuit under test are individually converted into oscillators. The parameters of the generated signal, such as the frequency and amplitude, can be expressed as function of the components used in the oscillator implementation. This way, it is possible to detect faults in the FPAA simply observing such parameters. This method is firstly studied considering an external analysis of the signal parameters. However, in a second moment, an internal response analyzer, based on a double integrator, is built with the available programmable resources of the FPAA. This way, overall test cost is reduced, while the fault coverage is increased with no area overhead. The obtained results considering the external analysis and the built-in response evaluation are compared. The second considered FPAA, from Anadigm Company, is a switched capacitor device whose programming characteristic is strictly functional. Thus, a structural test method cannot be easily developed and applied without the previous knowledge of he device architectural details. For this reason, a functional test method known as TRAM (Transient Response Analysis Method) is adopted. In this method the Circuit Under Test (CUT) is programmed to implement first and second order blocks and the transient response of these blocks for a given input stimuli is analyzed. Taking advantage of the inherent programmability of the FPAAs, a BIST-based scheme is used in order to obtain an error signal representing the difference between the fault-free and faulty Configurable Analog Blocks (CABs). As a proposal to augmenting the observability, the error signal is integrated, enhancing de fault detection capability when using this method. In both developed strategies the main objective is to test the CABs of the FPAAs exploiting the device programmability, using the existing resources in order to aid the test. The obtained results show that the developed strategies represent good alternatives to the built-in self-test of such type of device.

Neste trabalho o teste de dispositivos analógicos programáveis é abordado. Diversas metodologias de teste analógico existentes são estudadas e algumas delas são utilizadas nas estratégias desenvolvidas. Dois FPAAs (Field Programmable Analog Arrays) comerciais de fabricantes e modelos distintos são utilizados para validar as estratégias de teste propostas. O primeiro dispositivo estudado é um FPAA de tempo contínuo (capaz de implementar circuitos contínuos no tempo) da Lattice Semiconductors. Tal dispositivo é marcado pela característica estrutural de sua programabilidade. Por esta razão, a estratégia a ele aplicada é baseada em um método de teste também estrutural, conhecido como OBT (Oscillation-Based Test). Neste método o circuito é dividido em blocos simples que são transformados em osciladores. Os parâmetros do sinal obtido, tais como a freqüência de oscilação e a amplitude, têm relação direta com os componentes utilizados na implementação do oscilador. Desta maneira, é possível detectar falhas no FPAA observando os parâmetros do sinal gerado. Esta estratégia é estudada inicialmente considerando uma análise externa dos parâmetros do sinal. Como uma alternativa de redução de custos e melhoria na cobertura de falhas, um analisador de resposta baseado em um duplo integrador é adotado, permitindo que a avaliação do sinal gerado pelo oscilador seja feita internamente, utilizando-se os recursos programáveis do próprio FPAA. Os resultados obtidos para as análises interna e externa são então comparados. O segundo FPAA estudado, da Anadigm Company, é um dispositivo a capacitores chaveados que tem como característica a programabilidade funcional. Por esta razão o desenvolvimento de uma técnica de teste estrutural é dificultado, pois não se conhece detalhes da arquitetura do componente. Por esta razão, uma técnica de teste funcional, conhecida como Transient Response Analysis Method, é aplicada ao teste deste FPAA. Neste método o circuito sob teste é dividido em blocos funcionais de primeira e segunda ordem e a resposta transiente destes blocos para um dado estímulo de entrada é analisada. O bloco sob teste é então duplicado e um esquema de auto-teste integrado baseado em redundância é desenvolvido, com o intuito de se obter um sinal de erro. Este sinal de erro representa a diferença das respostas transientes dos blocos duplicados. Como proposta para se aumentar a observabilidade do sinal de erro o mesmo é integrado ao longo tempo, aumentando a capacidade de detecção de falhas quando utilizado este método. Em ambas estratégias o objetivo principal do trabalho é testar os blocos analógicos programáveis dos FPAAs explorando ao máximo a programabilidade dos dispositivos e utilizando recursos pré-existentes para auxiliar no teste. Os resultados obtidos mostram que as estratégias desenvolvidas configuram boas alternativas para o auto-teste integrado deste tipo de componente. / This work addresses the test of programmable analog devices. Several analog test methodologies are studied and some of them are applied in the developed strategies. In order to validate these strategies, two commercial FPAAs (Field Programmable Analog Arrays), of different vendors and distinct models, are considered as devices under test. The first studied device is a continuous-time FPAA from Lattice Semiconductors. One important characteristic of such device is the structural programmability. For this reason the test strategy applied to this FPAA is based in a structural method known as OBT (Oscillation-Based Test). In this method, blocks of the circuit under test are individually converted into oscillators. The parameters of the generated signal, such as the frequency and amplitude, can be expressed as function of the components used in the oscillator implementation. This way, it is possible to detect faults in the FPAA simply observing such parameters. This method is firstly studied considering an external analysis of the signal parameters. However, in a second moment, an internal response analyzer, based on a double integrator, is built with the available programmable resources of the FPAA. This way, overall test cost is reduced, while the fault coverage is increased with no area overhead. The obtained results considering the external analysis and the built-in response evaluation are compared. The second considered FPAA, from Anadigm Company, is a switched capacitor device whose programming characteristic is strictly functional. Thus, a structural test method cannot be easily developed and applied without the previous knowledge of he device architectural details. For this reason, a functional test method known as TRAM (Transient Response Analysis Method) is adopted. In this method the Circuit Under Test (CUT) is programmed to implement first and second order blocks and the transient response of these blocks for a given input stimuli is analyzed. Taking advantage of the inherent programmability of the FPAAs, a BIST-based scheme is used in order to obtain an error signal representing the difference between the fault-free and faulty Configurable Analog Blocks (CABs). As a proposal to augmenting the observability, the error signal is integrated, enhancing de fault detection capability when using this method. In both developed strategies the main objective is to test the CABs of the FPAAs exploiting the device programmability, using the existing resources in order to aid the test. The obtained results show that the developed strategies represent good alternatives to the built-in self-test of such type of device.

Neste trabalho o teste de dispositivos analógicos programáveis é abordado. Diversas metodologias de teste analógico existentes são estudadas e algumas delas são utilizadas nas estratégias desenvolvidas. Dois FPAAs (Field Programmable Analog Arrays) comerciais de fabricantes e modelos distintos são utilizados para validar as estratégias de teste propostas. O primeiro dispositivo estudado é um FPAA de tempo contínuo (capaz de implementar circuitos contínuos no tempo) da Lattice Semiconductors. Tal dispositivo é marcado pela característica estrutural de sua programabilidade. Por esta razão, a estratégia a ele aplicada é baseada em um método de teste também estrutural, conhecido como OBT (Oscillation-Based Test). Neste método o circuito é dividido em blocos simples que são transformados em osciladores. Os parâmetros do sinal obtido, tais como a freqüência de oscilação e a amplitude, têm relação direta com os componentes utilizados na implementação do oscilador. Desta maneira, é possível detectar falhas no FPAA observando os parâmetros do sinal gerado. Esta estratégia é estudada inicialmente considerando uma análise externa dos parâmetros do sinal. Como uma alternativa de redução de custos e melhoria na cobertura de falhas, um analisador de resposta baseado em um duplo integrador é adotado, permitindo que a avaliação do sinal gerado pelo oscilador seja feita internamente, utilizando-se os recursos programáveis do próprio FPAA. Os resultados obtidos para as análises interna e externa são então comparados. O segundo FPAA estudado, da Anadigm Company, é um dispositivo a capacitores chaveados que tem como característica a programabilidade funcional. Por esta razão o desenvolvimento de uma técnica de teste estrutural é dificultado, pois não se conhece detalhes da arquitetura do componente. Por esta razão, uma técnica de teste funcional, conhecida como Transient Response Analysis Method, é aplicada ao teste deste FPAA. Neste método o circuito sob teste é dividido em blocos funcionais de primeira e segunda ordem e a resposta transiente destes blocos para um dado estímulo de entrada é analisada. O bloco sob teste é então duplicado e um esquema de auto-teste integrado baseado em redundância é desenvolvido, com o intuito de se obter um sinal de erro. Este sinal de erro representa a diferença das respostas transientes dos blocos duplicados. Como proposta para se aumentar a observabilidade do sinal de erro o mesmo é integrado ao longo tempo, aumentando a capacidade de detecção de falhas quando utilizado este método. Em ambas estratégias o objetivo principal do trabalho é testar os blocos analógicos programáveis dos FPAAs explorando ao máximo a programabilidade dos dispositivos e utilizando recursos pré-existentes para auxiliar no teste. Os resultados obtidos mostram que as estratégias desenvolvidas configuram boas alternativas para o auto-teste integrado deste tipo de componente. / This work addresses the test of programmable analog devices. Several analog test methodologies are studied and some of them are applied in the developed strategies. In order to validate these strategies, two commercial FPAAs (Field Programmable Analog Arrays), of different vendors and distinct models, are considered as devices under test. The first studied device is a continuous-time FPAA from Lattice Semiconductors. One important characteristic of such device is the structural programmability. For this reason the test strategy applied to this FPAA is based in a structural method known as OBT (Oscillation-Based Test). In this method, blocks of the circuit under test are individually converted into oscillators. The parameters of the generated signal, such as the frequency and amplitude, can be expressed as function of the components used in the oscillator implementation. This way, it is possible to detect faults in the FPAA simply observing such parameters. This method is firstly studied considering an external analysis of the signal parameters. However, in a second moment, an internal response analyzer, based on a double integrator, is built with the available programmable resources of the FPAA. This way, overall test cost is reduced, while the fault coverage is increased with no area overhead. The obtained results considering the external analysis and the built-in response evaluation are compared. The second considered FPAA, from Anadigm Company, is a switched capacitor device whose programming characteristic is strictly functional. Thus, a structural test method cannot be easily developed and applied without the previous knowledge of he device architectural details. For this reason, a functional test method known as TRAM (Transient Response Analysis Method) is adopted. In this method the Circuit Under Test (CUT) is programmed to implement first and second order blocks and the transient response of these blocks for a given input stimuli is analyzed. Taking advantage of the inherent programmability of the FPAAs, a BIST-based scheme is used in order to obtain an error signal representing the difference between the fault-free and faulty Configurable Analog Blocks (CABs). As a proposal to augmenting the observability, the error signal is integrated, enhancing de fault detection capability when using this method. In both developed strategies the main objective is to test the CABs of the FPAAs exploiting the device programmability, using the existing resources in order to aid the test. The obtained results show that the developed strategies represent good alternatives to the built-in self-test of such type of device.

Scandinavian Airlines has a large database containing their Eurobonus members. In order to analyze which customers they should target with direct marketing, such as emails, uplift models have been used. With a binary response variable that indicates whether the customer has bought or not, and a binary dummy variable that indicates if the customer has received the campaign or not conclusions can be drawn about which customers are persuadable. That means that the customers that buy when they receive a campaign and not if they don't are spotted. Analysis have been done with one campaign for Sweden and Scandinavia. The methods that have been used are logistic regression with Lasso and logistic regression with Penalized Net Information Value. The best method for predicting purchases is Lasso regression when comparing with a confusion matrix. The variable that best describes persuadable customers in logistic regression with PNIV is Flown (customers that have own with SAS within the last six months). In Lassoregression the variable that describes a persuadable customer in Sweden is membership level1 (the rst level of membership) and in Scandinavia customers that receive campaigns with delivery code 13 are persuadable, which is a form of dispatch.

In this thesis the heterogeneity of regional real estate prices in United States is investigated. A high dimensional VAR model with additional exogenous predictors, originally introduced by \cite{fan11}, is adopted. In this framework, the common factor in regional house prices dynamics is explained by exogenous predictors and the spatial dependencies are captured by lagged house prices in other regions. For the purpose of estimation and variable selection under high-dimensional setting the concept of Penalized Least Squares (PLS) with different penalty functions (e.g. LASSO penalty) is studied in detail and implemented. Moreover, clustering methods are employed to identify subsets of statistical regions with similar house prices dynamics. It is demonstrated that these clusters are well geographically defined and contribute to a better interpretation of the VAR model. Next, we make use of the LASSO variable selection property in order to construct the impulse response functions and to simulate the prices behavior when a shock occurs. And last but not least, one-period-ahead forecasts from VAR model are compared to those from the Diffusion Index Factor Model by \cite{stock02}, a commonly used model for forecasts.

he thesis focuses on building of dynamic mathematical model of biomass boiler as a controlled system and the use of this model in practise. At the first part of the thesis the area of energy production using biomass is introduced and the current development at the area of the automatic control of biomass boilers with medium energy output (in units of MW) is described. Although the main topic of the thesis is the construction of model of biomass boiler for control purposes, thesis deals with technology of boilers and principles of its inner processes as well. Creation of the model comes out not only from these important findings, but also from experimental data collected during measurements in real operation. Heat and mass balance calculations were made according to these data and they serve to precise static properties of experimental unit for biomass combustion. Central part of the thesis presents development of the final model that resulted from balance calculations and from step responses of the system obtained by measuring. Built dynamic model is compared with experimental data through simulations in Simulink and verified. At the next part the model of controlled system is completed with control system and closed-loop control circuit is validated and verified by simulation. Then the design of new controller configuration, which improves the quality of control considerably, is presented. At the final part of the thesis, possibilities of other use of the model of boiler are given, both in control theory and in industrial practice.

Frequency response analysis (FRA) is a method which is used to detect mechanical faults in transformers. The FRA response of a transformer is determined by its geometry and material properties, and it can be considered as the transformer’s fingerprint. If there are any mechanical changes in the transformer, for example if the windings are moved or distorted, its fingerprint will also be changed so, theoretically, mechanical changes in the transformer can be detected with FRA. The purpose of this thesis is to partly create a simple model for the ferromagnetic material in the transformer core, and partly to investigate the high frequency part of the FRA response of the transformer winding. To be able to realize these goals, two different models are developed separately from each other. The first one is a time- and frequency domain complex permeability model for the ferromagnetic core material, and the second one is a time- and frequency domain winding model based on lumped circuits, in which the discretization is made finer and finer in three steps. Capacitances and inductances in the circuit are calculated with use of analytical expressions derived from approximated geometrical parameters. The developed core material model and winding model are then implemented in MATLAB separately, using state space analysis for the winding model, to simulate the time- and frequency response. The simulations are then compared to measurements to verify the correctness of the models. Measurements were performed on a magnetic material and on a winding, and were compared with obtained results from the models. It was found that the model developed for the core material predicts the behavior of the magnetic field for frequencies higher than 100 Hz, and that the model for the winding predicts the FRA response of the winding for frequencies up to 20 MHz.

Recent advancements in machine learning have started to put their mark on educational technology. Technology is evolving fast and, as people adopt it, schools and universities must also keep up (nearly 70% of primary and secondary schools in the UK are now using tablets for various purposes). As these numbers are likely going to follow the same increasing trend, it is imperative for schools to adapt and benefit from the advantages offered by technology: real-time processing of data, availability of different resources through connectivity, efficiency, and many others. To this end, this work contributes to the growth of educational technology by developing several algorithms and models that are meant to ease several tasks for the instructors, engage students in deep discussions and ultimately, increase their learning gains. First, a novel, fine-grained knowledge representation is introduced that splits phrases into their constituent propositions that are both meaningful and minimal. An automated extraction algorithm of the propositions is also introduced. Compared with other fine-grained representations, the extraction model does not require any human labor after it is trained, while the results show considerable improvement over two meaningful baselines. Second, a proposition alignment model is created that relies on even finer-grained units of text while also outperforming several alternative systems. Third, a detailed machine learning based analysis of students' unrestricted natural language responses to questions asked in classrooms is made by leveraging the proposition extraction algorithm to make computational predictions of textual assessment. Two computational approaches are introduced that use and compare manually engineered machine learning features with word embeddings input into a two-hidden layers neural network. Both methods achieve notable improvements over two alternative approaches, a recent short answer grading system and DiSAN – a recent, pre-trained, light-weight neural network that obtained state-of-the-art performance on multiple NLP tasks and corpora. Fourth, a clustering algorithm is introduced in order to bring structure to the feedback offered to instructors in classrooms. The algorithm organizes student responses based on three important aspects: propositional importance classifications, computational textual understanding of student understanding and algorithm similarity metrics between student responses. Moreover, a dynamic cluster selection algorithm is designed to decide which are the best groups of responses resulting from the cluster hierarchy. The algorithm achieves a performance that is 86.3% of the performance achieved by humans on the same task and dataset. Fifth, a deep neural network is built to predict, for each cluster, an engagement response that is meant to help generate insightful classroom discussion. This is the first ever computational model to predict how engaging student responses will be in classroom discussion. Its performance reaches 86.8% of the performance obtained by humans on the same task and dataset. Moreover, I also demonstrate the effectiveness of a dynamic algorithm that can self-improve with minimal help from the teachers, in order to reduce its relative error by up to 32%.

No description available.

The suspension system in vehicles supports the vehicle's road stability and ride quality by scaling down the vibration responses resulting from road surface's roughness. This research focuses on fatigue life analysis of coil spring component. Static linear analysis is conducted on the 3D model of helical coil spring to investigate deformation and stress responses. Modal analysis evaluates the characteristics of vibration, i.e. natural resonance frequencies and corresponding mode shapes. The stress frequency response is generated after performing the harmonic analysis on the spring. Dynamics and performance of spring are analyzed over practical frequency range of 0 Hz to 200 Hz. Fatigue life estimation of vehicle suspension spring is performed using the stress data obtained from frequency response analysis. The stress-life (S-N) approach is utilized for fatigue life assessment of suspension spring. This durability analysis technique can be utilized in the automotive industry to improve reliability of vehicles. The outcome of this research can contribute in analysis and design of modern smart vehicles. / Master of Science / The suspension system in vehicles supports the vehicle's road stability and ride quality by scaling down the vibration responses resulting from road surface's roughness. This research focuses on the fatigue life analysis of suspension spring component. Initial phase of analysis is conducted to investigate the deformation and stress in 3D model of spring. Dynamics and performance of spring are analyzed over applicable frequency range of 0 Hz to 200 Hz. Fatigue life of vehicle suspension spring is evaluated using stress data from frequency response analysis. This durability analysis technique can be utilized in the automotive industry to improve reliability of vehicles. The outcome of this research can contribute in analysis and design of modern smart vehicles.