A channel model is a mathematical or conceptual representation employed to describe the behavior and characteristics of a communication channel through which signal or data can be transferred from the transmitter (Tx) to the receiver (Rx) or between two transceivers. In wireless communication, the channel model represents the wireless medium with parameters like pathloss, impulse response, and multipath effects. A2A channel poses various challenges when UAVs operate at a higher altitude greater than 1000 ft (305 m). This thesis involves experiments having a range of altitudes from 20 m to 2 km and distances between two transceivers from 5 m to 3 km. This thesis aims to introduce A2A channel by considering and analyzing inherent channel characteristics such as pathloss in terms of line-of-sight (LOS) and non-line-of-sight (NLOS), multipath fading, delay spread, and power delay profile (PDP). These characteristics depend on frequency, altitude of transmitter (Tx) and receiver (Rx), distance between two transceivers, antenna properties, paths taken by the signals, and obstacles. Pathloss, RMS delay spread, and power delay profile have been discussed with the simulated graphs by varying the distances and altitudes. These channel characteristics have been analyzed for different conditions like varying building heights of the city, changing building material, and also changing both building height and material at the same time. Two empirical models, the EL model and the CI model, have been presented along with simulations. Simulation results using mmWave frequency have been shown. The simulations have been performed by Wireless Insite software.

Os objetivos deste trabalho vão da apresentação do andamento das pesquisas relacionadas à análise de distúrbios associados à qualidade da energia elétrica (QEE), até a proposta de um algoritmo baseado em diversas ferramentas para a detecção e localização no tempo, bem como a classificação automática destes distúrbios. Nesta pesquisa é proposta uma detecção não somente do início e fim de um único evento, mas também, de n possíveis desconformidades na forma de onda que possam vir a ocorrer ou existir em determinados registros e/ou arquivos de dados em análise. Como diferencial deste trabalho, tem-se que da determinação da localização das alterações/descontinuidades na forma de onda, foi possível obter janelas de dados com tamanhos flexíveis. Desta maneira, vários eventos sobre o sinal em análise puderam ser avaliados, bem como as durações associadas. Para isso, a Transformada Wavelet (TW) foi utilizada para realizar a detecção e também a localização destas alterações no tempo. Já para a classificação da ocorrência, ou das ocorrências, a TW, a Transformada de Fourier (TF) e o valor RMS foram empregados. A flexibilidade das janelas de dados permitiu uma adequada escolha de qual ferramenta poderia ser mais bem utilizada na classificação. Conforme implementado, cada uma destas ferramentas apresenta uma resposta e através de um módulo de decisão lógica é determinada a resposta final do algoritmo. Para validar o estudo, várias situações de distúrbios foram caracterizadas referentes a um sistema elétrico de distribuição real, implementado e simulado pela aplicação do software ATP (Alternative Transients Program). Os resultados obtidos foram excelentes tanto para a detecção e localização no tempo, como para a classificação e estimação da amplitude e duração dos eventos. / The objectives of this work are going since the presentation of the researches related to the analyses of power quality (PQ) disturbances through the proposal of an algorithm based on several tools for detection and location in time, as well as the automatic classification of these phenomena. It is proposed to determine not only the initial and the end of a unique event, but all the n possible disconformities in the waveform that can exist or occur in the data file registered data in analyses. As the differential of this research, from the location in time of the alteration/discontinuities in the waveforms, it was possible to obtain data windows with flexible sizes. So, several events on the signal were evaluated, as well as their specific timeduration. For this purpose, the Wavelet transform (WT) was used to reach the detection and localization in time of the waveform alterations. For the event classification, the TW, the Fourier transform (FT) and the Root Mean Square (RMS) value were used. The data window flexibility allowed an appropriate choice of which tool could be better used in the classification task. As implemented, each one of these tools presented an answer, and the final answer was obtained by using a logic decision module. To validate the study, some situations of disturbances were characterized using a real distribution system, implemented and simulated applying the ATP (Alternative Transients Program) software. The results were excellent in such a way for detection and localization in time, as well as for the automatic classification and estimation of the magnitude and the event duration.

Os objetivos deste trabalho vão da apresentação do andamento das pesquisas relacionadas à análise de distúrbios associados à qualidade da energia elétrica (QEE), até a proposta de um algoritmo baseado em diversas ferramentas para a detecção e localização no tempo, bem como a classificação automática destes distúrbios. Nesta pesquisa é proposta uma detecção não somente do início e fim de um único evento, mas também, de n possíveis desconformidades na forma de onda que possam vir a ocorrer ou existir em determinados registros e/ou arquivos de dados em análise. Como diferencial deste trabalho, tem-se que da determinação da localização das alterações/descontinuidades na forma de onda, foi possível obter janelas de dados com tamanhos flexíveis. Desta maneira, vários eventos sobre o sinal em análise puderam ser avaliados, bem como as durações associadas. Para isso, a Transformada Wavelet (TW) foi utilizada para realizar a detecção e também a localização destas alterações no tempo. Já para a classificação da ocorrência, ou das ocorrências, a TW, a Transformada de Fourier (TF) e o valor RMS foram empregados. A flexibilidade das janelas de dados permitiu uma adequada escolha de qual ferramenta poderia ser mais bem utilizada na classificação. Conforme implementado, cada uma destas ferramentas apresenta uma resposta e através de um módulo de decisão lógica é determinada a resposta final do algoritmo. Para validar o estudo, várias situações de distúrbios foram caracterizadas referentes a um sistema elétrico de distribuição real, implementado e simulado pela aplicação do software ATP (Alternative Transients Program). Os resultados obtidos foram excelentes tanto para a detecção e localização no tempo, como para a classificação e estimação da amplitude e duração dos eventos. / The objectives of this work are going since the presentation of the researches related to the analyses of power quality (PQ) disturbances through the proposal of an algorithm based on several tools for detection and location in time, as well as the automatic classification of these phenomena. It is proposed to determine not only the initial and the end of a unique event, but all the n possible disconformities in the waveform that can exist or occur in the data file registered data in analyses. As the differential of this research, from the location in time of the alteration/discontinuities in the waveforms, it was possible to obtain data windows with flexible sizes. So, several events on the signal were evaluated, as well as their specific timeduration. For this purpose, the Wavelet transform (WT) was used to reach the detection and localization in time of the waveform alterations. For the event classification, the TW, the Fourier transform (FT) and the Root Mean Square (RMS) value were used. The data window flexibility allowed an appropriate choice of which tool could be better used in the classification task. As implemented, each one of these tools presented an answer, and the final answer was obtained by using a logic decision module. To validate the study, some situations of disturbances were characterized using a real distribution system, implemented and simulated applying the ATP (Alternative Transients Program) software. The results were excellent in such a way for detection and localization in time, as well as for the automatic classification and estimation of the magnitude and the event duration.

Made available in DSpace on 2014-07-29T15:08:19Z (GMT). No. of bitstreams: 1 dissertacao RamonCampos UFG 2012.pdf: 5667385 bytes, checksum: 1ff8645bd9d1b27aa406264298e405ef (MD5) Previous issue date: 2012-07-09 / This study aimed to development of a computational tool for electromyographic signal (EMG) analysis by signal processing techniques to determine muscular fatigue. With Ethics Committee of Federal University of Goiás approve were recorded from the dominant biceps brachii of 10 volunteers, that did not ever had muscular disease. The protocol consisted on get the maximal voluntary isometric contraction (MVIC) from the volunteer seated, floor contact with the feet, and forearm in 90 degree, doing three maximal voluntary contraction against a rigid and fixed surface, by five seconds, with a five resting minutes between each acquisition. The MVIC values were obtained by arithmetical mean from the three greater values of each contraction. In statistical analysis the volunteer sustained a load of 60% MVIC for 30 seconds, or while they supported. For dynamical analysis was used a electrogoniometer tied in forearm to measure the angle and a 60% MVIC load for 30 seconds measured, achieved angle of 70° until 130°, and return to 70°. Each flexion was did in 1,5 seconds, or while volunteer support. To analyze the signal in time domain were used Root main square (RMS) values and Continuous wavelet transform (CWT). To analyze in frequency domain were adopted the values of mean and median from Fast Fourier Transform (FFT), Welch spectral estimator, auto regressive moving average (ARMA) filter, and analytic wavelet transform (AWT). Linear regressions were obtained using a window of 250 ms for all techniques. Slopes with positive values, in time domain, and slopes with negative values, in frequency domain, indicate muscular fatigue. Using high scales of wavelet transform shows great results while compared with default techniques, like RMS and FFT. ANOVA one way were adopted as statistical method of analysis, with P < 0,05. Only in dynamic contraction, on frequency domain, had P value < 0,05. Tukey test were applied to identify which techniques had variance great than 5%. Is suggested as future works development of a wireless system to acquire EMG signals, improvement in the software to motor unit action potentials (MUAP) detection, prosthesis control, and synchronization with others systems of data collection. / Este trabalho propõe o desenvolvimento de uma ferramenta computacional para realizar a análise do sinal eletromiográfico (EMG) por meio de técnicas de processamento de sinais a fim de detectar fadiga muscular. Com aprovação do Comitê de Ética da Universidade Federal de Goiás, foram captados os sinais eletromiográfico do bíceps braquial do braço dominante de 10 voluntários, que não apresentavam histórico de problemas musculares. O protocolo consistiu na obtenção do valor de contração isométrica voluntária máxima (CIVM) com o voluntário sentado, pés em contato com o chão e o antebraço em ângulo de 90° em relação ao tronco, realizando três repetições de contração máxima, contra uma superfície fixa e rígida, durante 5 segundos, intercaladas por um período de 5 minutos em repouso. O valor da CIVM, representando 100% da força máxima exercida, foi determinado por meio da média aritmética dos maiores valores de cada amostra. Para análise de contração estática, o voluntário realizou uma nova contração com carga de 60% da CIVM durante 30 segundos, ou até onde suportasse. Na análise de contração dinâmica, foi utilizado um eletrogoniômetro para medição do ângulo do antebraço que, ao carregar uma carga com 60% da CIVM, realizou manobra de flexão, alcançando ângulo de 70°, e manobra de extensão, atingindo ângulo de 130° do antebraço em relação ao tronco. Cada manobra (flexão e extensão) foi realizada em 1,5 segundos, durante um período de 30 segundos ou enquanto suportasse, totalizando no máximo de 10 flexões e 10 extensões. Foram adotadas para análise do sinal EMG no domínio do tempo as técnicas de cálculo do valor quadrático médio (RMS) e transformada wavelet contínua (TWC). Para análise no domínio da frequência foram adotados os valores médios e medianos obtidos pelas técnicas de transformada rápida de Fourier (FFT), o estimador espectral de Welch, o filtro autorregressivo de média móvel (ARMA) e as transformadas wavelets analíticas (TWA). Utilizando uma janela de 250 ms foram obtidos os gráficos contendo a regressão linear de todas as técnicas. A inclinação positiva da reta de regressão, para o domínio do tempo, e inclinação negativa, para o domínio da frequência, indica o processo de fadiga muscular. A utilização da transformada wavelet, em grandes escalas, apresenta valor mais significativo de indícios de fadiga muscular quando comparada às técnicas padrões RMS e FFT. O método estatístico utilizado foi a ANOVA de um fator, com o P < 0,05. Apenas na contração dinâmica no domínio da frequência obteve um P < 0,05. Aplicada a análise post hoc do teste de Tukey foram identificadas, das técnicas comparadas duas a duas, quais apresentaram um grau de variância maior que 5%. Ainda no trabalho é sugerido o desenvolvimento de equipamento de coleta de sinais EMG sem fio, o aperfeiçoamento da ferramenta desenvolvida para detecção de potenciais de ativação de unidade motora (MUAP), o controle de próteses de reabilitação, e a sincronização com outros sistemas de coleta de dados.

This thesis deals with the effect of frequency inverter on the lifetime of roller bearings. The measurement has been carried out on the frequency inverter and induction motor by Siemens in the Switchgear laboratory of Fakulty of elektrical engineering and communication. Data has been recorded and processed on Adash VA4 Pro analyzer. Methods of measuring RMS values and frequency analysis of vibration and current were used for the analysis. Based on the mutual similarity of frequency spectrum, the presence of the high frequency capacitive current in the bearings has been proven. To prevent this, possible solutions have been presented. In the second part of the experiment an effect of changing pulse width modulation (PWM) on vibration was examined. The goal was to make a basic analysis and to provide background material for further research.

La litière de fumier recyclé (LFR) est utilisée dans les fermes canadiennes comme alternative à la litière conventionnelle de paille. Elle est obtenue par l’extraction de la fraction solide du fumier des vaches, parfois suivie par une maturation. Toutefois, les caractéristiques microbiologiques de cette litière sont peu documentées. Ainsi, cette étude a permis la description du microbiote et des caractéristiques microbiologiques de la LFR comparativement à la paille, avant et après leur utilisation, et d’évaluer l’impact de différentes méthodes de production de la LFR sur ces écosystèmes. Les résultats des analyses du microbiote ont démontré que la richesse et la diversité du microbiote de la LFR avant utilisation étaient différentes de celles de la paille. Les litières de fumier recyclé avant et après utilisation possédaient une diversité microbienne moindre comparativement à celles mesurées pour la paille avant et après utilisation. Aussi, les différentes méthodes de production de la LFR n’influençaient pas la richesse du microbiote, mais influencent sa composition. La méthode de production utilisant la séparation suivie d’une maturation en amas possédait une charge bactérienne moindre que celle utilisant la séparation suivit d’une maturation en boîte. Finalement, la LFR contenait plus de Listeria monocytogenes et de Salmonella spp que la litière de paille. Cela permet de conclure que la LFR, actuellement produite dans les fermes de l'Est du Canada, constitue un risque microbiologique plus élevé que la litière de paille. / Recycled manure solid bedding (RMS) is used on Canadian farms as an alternative to conventional straw bedding. RMS is obtained by extracting the solid fraction of dairy cow manure, sometimes followed by maturation. However, the microbiological characteristics of this bedding are poorly documented. This study allowed the description of the microbiota and microbiological characteristics of RMS compared to straw and assessed the impact of the RMS production methods on its microbiota. The results of the microbiota analyses demonstrated that the richness and diversity of the microbiota in unused RMS were different from unused straw. Unused RMS and used RMS possessed more similar microbial diversity compared to the microbial diversity between unused and used straw. Moreover, the different RMS production methods did not influence the richness of the microbiota but influence its composition. The RMS production method using separation followed by heap maturation had a lower bacterial load than production method using separation followed by box maturation. Finally, RMS contained more Listeria monocytogenes and Salmonella spp than straw bedding. This leads to the conclusion that RMS bedding currently produced on farms in Eastern Canada, clearly constitute a greater microbiological risk as compared to straw bedding.

This research has been focused on the characterisation and analysis of the deposits of large-scale mass movement events that shaped the North Sea Fan since the Mid-Pleistocene. Located at the mouth of the cross-shelf trough Norwegian Channel, the North Sea Fan is one of the largest through-mouth fans in the glaciated european margin with an area of approximately 142,000 km2. Submarine mass movement processed have occurred intermittenrly throughout the Quarternary history of the North Sea Fan, related to recurrent climate-related episodes of growth and retreat of the ice sheets. These processes can transport large amounts of sediment from the upper shelf up to the abyssal basins, playing an important role on the evolution of continental margins and can also reporesnet major geological hazards. This thesis uses mainly 3D seismic data to investigate the external geometry and internal structure of large-scale mass movement deposits. The high spatial resolution provided by the 3D seismic data has allowed a detailed geomorpholocial analysis of these deposits, This study involved the interpretation of the seismic data and the detailed pickling of key reflectors followed by tge extraction of both horizon and window-based seismic attributes. Digital elevation models of the key reflectors and their seismic attribute maps were then transferred to a geographical information system (GIS) where they were interactively interpreted using spatial analysis tools and the full visualisation potential of the software. The outcomes of this study highlight the importance of detailed horizon pickling and interactice interpretation followed by spatial analysis and visualisation in GIS environment. The identification of acoustic patterns within deposits that are normally described from 2D seismic as chaotic or acoustically transparent emphasizes the potential of detailed analysis of 3D seismic data. It gives an example of how this type of data can provide new insights into the mechanisms and processes associated with mass movements. In particular, amplitude and RMS amplitude maps provide remarkable detailed information of internal deformation structures whereas slope, shaded-relief and thickness maps allowed detailed characterisation of the external geometry. Various types of kinematic indicators can be recognized within the mass movement deposits through combined seismic analysis and detaield morphological mapping.

The fiber reinforced polymer (FRP) bars have been widely used in pre-stressing applications and reinforcing of the civil structures. High strength-to-weight ratio and high resistance to the corrosion make the FRP bars a good replacement for steel reinforcing bars in civil engineering applications. According to the CAN/CSA-S806-12 standard, the maximum recommended stress in FRP bars under service loads should not exceed 25% and 65% of the ultimate strength for glass FRP (GFRP) and carbon FRP (CFRP), respectively. These stress values are set to prevent creep failure in FRP bars. However, for in-service applications, there are few physical indicators that these values have been reached or exceeded. In this work analysis of acoustic emission (AE) signals is used. Two new techniques based on pattern recognition and frequency entropy of the isolated acoustic emission (AE) signal are presented for monitoring damage progression and prediction of failure in FRPs. / May 2017

Sophisticated power electronic apparatus and their digital control systems are finding increasing applications in electric power systems at generation, transmission, distribution and utilization levels. It is essential to carry out rigorous performance evaluation of such apparatus before commissioning. Field Programmable Gate Arrays (FPGAs) are becoming an attractive platform for accelerating computationally intensive applications. This thesis presents a FPGA-based real-time digital simulator for power electronic drives based on realistic device characteristics. A 3-level 12-pulse Voltage Source Converter (VSC) fed induction machine drive is implemented on the FPGA. The system components include the 3-level VSC, the induction machine, the direct field oriented controller, and the pulse width modulator. Both system-level and device-level IGBT models are utilized to implement the VSC. The VSC model is computed at a fixed time-step of 12:5ns allowing an accurate representation of the IGBT nonlinear switching characteristics. Altera Startix EP1S80 and EP3SL150F1152C2 FPGA boards utilized for the real-time simulation. All models were implemented in VHDL. The FPGA boards were interfaced to external DAC boards to display real-time results on the oscilloscope. The real-time results were validated using an off-line cosimulation set-up using the SABER and MATLAB/SIMULINK software. / Power Engineering and Power Electronics

No description available.