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Development of a High Speed, Robust System for Full Field-of-View 3D Shape MeasurementsZervas, Michael Jay 26 August 2011 (has links)
"3D shape measurements are critical in a range of fields, from manufacturing for quality measurements to art conservation for the everlasting archival of ancient sculptures. The most important factor is to gather quantitative 3D information from measurement devices. Currently, there are limitations of existing systems. Many of the techniques are contact methods, proving to be time consuming and invasive to materials. While non-contact methods provide opportunities, many of the current systems are limited in versatility. This project focuses on the development of a fringe projection based system for 3D shape measurements. The critical advantage of the fringe projection optical technique is the ability to provide full field-of-view (FOV) information on the order from several square millimeters to several square meters. In the past, limitations in speed and difficulties achieving sinusoidal projection patterns have restricted the development of this particular type of system and limited its potential applications. For this reason, direct coding techniques have been incorporated to the developed system that modulate the intensity of each pixel to form a sinusoidal pattern using a 624 nm wavelength MEMS based spatial light modulator. Recovered phase data containing shape information is obtained using varying algorithms that range from a single image FFT analysis to a sixteen image, phase stepping algorithm. Reconstruction of 3D information is achievable through several image unwrapping techniques. The first is a spatial unwrapping technique for high speed applications. Additionally, the system uses an optimized Temporal Phase Unwrapping (TPU) algorithm that utilizes varying fringe frequencies ranging from 4 to 512 pixels per fringe to recover shape information in the time domain. This algorithm was chosen based on its robustness and accuracy for high resolution applications [Burke et al., 2002]. Also, unwrapping errors are minimized by approximately 90% as the number of images used is increased from the minimum to maximum fringe density. Cxoontrary to other systems, the 3D shape measurement system developed in the CHSLT laboratories has unprecedented versatility to accommodate a variety of applications with the z-depth resolution of up to 25.4 µm (0.001 inches) and speeds close to 200 frames per second. Hardware systems are integrated into user-friendly software that has been customized for fringe projection. The system has been tested in two extreme environments. The first is for quantification of cracks and potholes in the surface of roads under dynamic conditions. The second application was digitization of an art sculpture under static conditions. The system shows promising results and the potential for high quality images via algorithm optimization. Most importantly, there is potential to present real time 3D information at video speeds."
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Double vision : a practice-based investigation of art and differential perceptionLyons, David January 2017 (has links)
<i>Double Vision: A practice- led investigation of art and differential perception</i> is a series of five interrelated practice-led research studies into artistic expression controlling perceptual experiences between audiences of varying visual acuities. Significant refinements occurred between the first and second, and second and third studies. The last four studies were conducted with the aim of understanding vision’s influence on perception. <i>Double Vision’s</i> lead methodological approach was artistic practice. Other methods were employed according to the needs of that practice. They included iteration, collaboration, exhibition and testing. The research questions of <i>Double Vision</i> were refined in response to the results of artistic practice. That evolution resulted in two interrelated questions: <i>Can artwork be intentionally created to be experienced differently dependent on one’s visual abilities? </i>and<i> If so, can those experiences be shared?</i> A further question, <i>‘Can an analogy to colour deficient vision be created that engages both those with colour vision deficiency and the typically sighted?’, </i>concludes the investigations. Artwork was realized through printmaking, animation and multimedia formats. Its context and content derived from many forms, notably the Ishihara <i>Test for Colour Deficiency</i>, writings of William Blake, contemporary music and philosophy. Augmented reality was employed to facilitate the translation of visual perceptions between targeted audiences. A number of exhibitions were held exploring these themes.
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Tendências de precipitação pluvial diária e projeção de cenários aplicados à nova curva IDF para Porto Alegre-RSWeschenfelder, Adriana Burin January 2017 (has links)
Neste estudo foram analisadas possíveis tendências de aumento da precipitação em nove estações pluviométricas na sub-bacia 87, incluindo Porto Alegre, no Estado do Rio Grande do Sul, para 50 anos de dados. Eventos extremos são responsáveis por muitos problemas, principalmente em áreas urbanas, e a frequência e a magnitude destes eventos podem aumentar com as alterações climáticas. No intuito de avaliar o impacto de alterações climáticas, em Porto Alegre, utilizou-se o modelo Long Ashton Research Station - Weather Generator (LARS-WG). O LARS-WG é um gerador estocástico capaz de simular cenários climáticos em escala local. Para cada série histórica das estações analisadas, na sub-bacia 87, foi aplicado o teste estatístico de Mann Kendall para identificar possíveis tendências nos dados anuais e trimestrais. Na estação de Porto Alegre também foi realizada pesquisa para identificar o aumento na frequência de ocorrência de alturas de precipitação em diferentes faixas e análise de tendência noshttp://www.bibliotecadigital.ufrgs.br/da.php?nrb=001053508&loc=2017&l=5219eb420c00bf62 dados sub-diários. A geração de séries sintéticas de precipitação para diferentes cenários teve como base os dados pluviométricos da série de Porto Alegre, que consistiu na utilização do período de 1974 a 2014 na geração da linha de base para calibração do LARS-WG. Após a geração de séries sintéticas de precipitação para um clima atual, foi selecionado o máximo diário anual e este foi desagregado em dados subdiários. Na sequência avaliou-se o impacto das alterações em três cenários do IPCC, A1B, A2 e B1. Em cada um dos arquivos de precipitação diária, geradas por projeção no LARS-WG, foi realizada a desagregação em precipitações sub-diárias Os resultados da aplicação do teste de Mann Kendall indicam tendência no aumento do total anual e no número de dias chuvosos (NDC). O trimestre que mais contribuiu para este aumento corresponde à primavera. Entretanto nas estações de Porto Alegre e Sapucaia do Sul, na região metropolitana de Porto Alegre, São Lourenço no Litoral Sul e Renânia e Serra do Pinto numa região de relevo acidentado próximo ao Litoral Norte também se identificou tendência de aumento no verão e no outono. Em Porto Alegre não foi verificada tendência na precipitação diária máxima anual, permitindo a utilização do LARS-WG que assume que as séries de dados diários observados são estacionárias e gera séries sintéticas com características estatísticas semelhantes à série de dados observados. Uma análise comparativa dos resultados entre as IDFs projetadas com o LARS-WG e a IDF definida por Weschenfelder et al. (2015) indica aumento das precipitações intensas. No primeiro período de projeção no cenário A1B, os desvios ficaram na faixa de 8 a 16% para quatro dos modelos, no cenário A2 os desvios ficaram na faixa de 9 a 19% e no cenário B1 de 7 a 19% em cinco modelos. Para o segundo período de projeção apresentou uma grande variabilidade com desvios entre -3 e 40%. O caminho para reduzir as incertezas é o monitoramento continuado das variáveis meteorológicas, pois a modelagem do clima só pode ser aprimorada com a incorporação de dados reais aos modelos. / This study analyzes possible trends of precipitation increase in nine rainfall stations in subbasin 87, including Porto Alegre, in the State of Rio Grande do Sul, for 50 years of data. Extreme events are responsible for many problems, especially in urban areas, and the frequency and magnitude of these events may increase with climate change. In order to evaluate the impact of climate change in Porto Alegre, the Long Ashton Research Station - Weather Generator (LARS-WG) model was used. The LARS-WG is a stochastic generator capable of simulating local scale climate scenarios. The Mann Kendall's statistical test was applied for each historical series of the analyzed stations in sub-basin 87 in order to identify possible trends in annual and trimestral data. At the Porto Alegre station, research was also conducted to identify the increase in the frequency of occurrence of precipitation heights in different bands and trend analysis in the sub-diary data. The generation of synthetic precipitation series for different scenarios was based on the pluviometric data of the Porto Alegre series, which consisted of the use of the period from 1974 to 2014 in the generation of the baseline for LARS-WG calibration After the generation of synthetic series of precipitation for a current climate, the maximum annual daily was selected and this was disaggregated in sub-diary data. The impact of the changes was then evaluated in three scenarios of the IPCC, A1B, A2 and B1. In each of the daily precipitation files generated by LARS-WG projection, disaggregation in sub-daily precipitation was conducted. The results of the Mann Kendall test indicate a trend in the annual total increase and in the number of rainy days (NDC). The trimester that contributed most to this increase is spring. However, in the Porto Alegre and Sapucaia do Sul stations, in the metropolitan area of Porto Alegre, São Lourenço in the South Coast and Renânia and Serra do Pinto, in an area of rugged relief near the North Coast, there was also a tendency to increase in summer and fall. In Porto Alegre, no trend was observed in the annual maximum daily precipitation, allowing the use of LARSWG, which assumes that the observed daily data series are stationary and generates synthetic series with similar statistical characteristics to the data series observed. A comparative analysis of the results between the IDFs projected with the LARS-WG and the IDF defined by Weschenfelder et al. (2015) indicates an increase in intense precipitation.
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Planejamento da qualidade para empresas prestadoras de serviço de transporte coletivo urbano por ônibus / Quality planning for urban collective transport service providers by busesAlves, Vanessa Teresinha January 2017 (has links)
Esta tese de doutorado parte do reconhecimento da essencialidade dos serviços públicos, em especial aos serviços de transporte coletivo. O objetivo principal é de cooperar com a inovação do processo de planejamento da qualidade do transporte coletivo urbano por ônibus e adequação destes serviços às suas demandas. Para a construção do método de planejamento da qualidade utilizou-se da metodologia construtivista. O framework foi elaborado a partir da combinação dos resultados da pesquisa teórica integrada às necessidades identificadas pela autora no ambiente em análise. As relações propostas foram estruturadas com base no método Quality Function Deployment (QFD), pois o interesse central foi incluir em um mesmo método de planejamento da qualidade, atributos importantes para os clientes usuários do sistema e o gerenciamento dos processos responsáveis pelo desempenho do serviço oferecido. Como forma de avaliar o método proposto, o mesmo foi aplicado em uma empresa prestadora do serviço de transporte coletivo urbano. A principal contribuição do artefato proposto está na ampliação das ações relacionadas à obtenção da qualidade, evidenciando que apenas o conhecimento sobre o nível de satisfação relacionado ao serviço de transporte coletivo urbano não permite oferecer um serviço de qualidade superior às expectativas dos clientes. É necessário adotar padrões de excelência e reconhecer qual a necessidade de investimentos para melhorar a qualidade e a eficiência no serviço de transporte coletivo urbano de forma contínua e sustentada. Através da aplicação, pôde-se concluir que o método atende as necessidades da empresa, servindo como guia para essencial melhoria da qualidade. / This doctoral thesis part of recognition of the essentiality of public services, particularly the collective urban transport services. The main objective is to cooperate with the innovation of quality planning process of urban collective transport by bus and adequacy of these services to their demands. For the construction of the method of projection of the quality it made use of the methodology constructivist. The framework was prepared from the combination of the results of the theoretical inquiry integrated to the necessities identified by the author in the environment in analysis.The proposed relations were structured on basis of the method Quality Function Deployment (QFD), since the central interest included in the same method of projection of the quality, important attributes for the users clients of the system and the management of the processes responsible for the performance of the offered service. Like the form of valuing the proposed method, the same thing was applied in a serviceable enterprise of the service of urbane collective transport. The main contribution of the proposed product is in the enlargement of the actions made a list to getting the quality, showing up that only the knowledge on the level of satisfaction made a list to the service of urbane collective transport does not allow offering a service of quality superior to the expectations of the clients. It is necessary to adopt standards of excellence and the investments necessity will recognize which to improve the quality and the efficiency in the service of urbane collective transport of continuous and supported form. Through the application, it was possible to end that the method attends the necessities of the enterprise, serving as a guide for effective improvement of the quality.
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Improving beamforming-based methodologies for seismological analysisTan, Fengzhou 10 April 2019 (has links)
We improved two beamforming-based methodologies for seismological analysis. The first one is a new Three-Dimensional Phase-Weighted Relative Back Projection (3-D PWBP) method to improve the spatial resolution of Back Projection results. We exploit both phase and amplitude of the seismogram signal to enhance the distinction of correlated signals. Also, we implement a 3-D velocity model to provide more accurate travel times. We vindicate these refinements with several synthetic tests and an analysis of the 1997 Mw 7.2 Zirkuh (Iran) earthquake, which we show ruptured mainly unilaterally southwards at a rupture speed of ∼3.0 km/s along its ∼125 km- long, mostly single-stranded surface rupture. Then, we apply the new method to the more complex case of the 2016 Mw 7.8 Kaikoura (New Zealand) earthquake, which we demonstrate is divided into two major stages separated by a gap of ∼8 s and ∼30–40 km. The overall rupture speed is ∼1.7 km/s and the overall duration is ∼84 s, considerably shorter than some earlier estimates. We see no clear evidence for continuous failure of the subduction interface that underlies the known, surface-rupturing crustal faults, though we cannot rule out its involvement in the second major stage in the northern part of the rupture area. The late (∼80 s) peak in relative energy is likely a high-frequency stopping phase, and the rupture appears to terminate southwest of the offshore Needles fault.
The second methodology is a novel workflow for earthquake detection and location, named Seismicity-Scanning based on Navigated Automatic Phase-picking (S-SNAP). By taking a cocktail approach that combines Source-Scanning, Kurtosis-based Phase-picking and the Maximum Intersection location technique into a single integrated workflow, this new method is capable of delineating complex spatiotemporal distributions of seismicity. It is automatic, efficiently providing earthquake locations with high comprehensiveness and accuracy. We apply S-SNAP to a dataset recorded by a dense local seismic array during a hydraulic fracturing operation to test this novel approach and to demonstrate the effectiveness of S-SNAP in comparison to existing methods. Overall, S-SNAP found nearly four times as many high-quality events as a template-matching based catalogue. All events in the previous catalogue are identi- fied with similar epicenter, depth and magnitude, while no false detections are found by visual inspection. / Graduate
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Noise and PSRR improvement technique for TPC readout front-end in CMOS. technology. / Técnica para melhoramento do ruído e PSRR para leitura de sinais do TPC em tecnologia CMOS.Hernández Herrera, Hugo Daniel 14 September 2015 (has links)
ALICE is one of four major experiments of particle accelerator LHC installed in the European laboratory CERN. The management committee of the LHC accelerator has just approved a program update for this experiment. Among the upgrades planned for the coming years of the ALICE experiment is to improve the resolution and tracking efficiency maintaining the excellent particles identification ability, and to increase the read-out event rate to 100 KHz. In order to achieve this, it is necessary to update the Time Projection Chamber detector (TPC) and Muon tracking (MCH) detector modifying the read-out electronics, which is not suitable for this migration. To overcome this limitation the design, fabrication and experimental test of new ASIC named SAMPA has been proposed . This ASIC will support both positive and negative polarities, with 32 channels per chip and continuous data readout with smaller power consumption than the previous versions. This work aims to design, fabrication and experimental test of a readout front-end in 130nm CMOS technology with configurable polarity (positive/negative), peaking time and sensitivity. The new SAMPA ASIC can be used in both chambers (TPC and MCH). The proposed front-end is composed of a Charge Sensitive Amplifier (CSA) and a Semi-Gaussian shaper. In order to obtain an ASIC integrating 32 channels per chip, the design of the proposed front-end requires small area and low power consumption, but at the same time requires low noise. In this sense, a new Noise and PSRR (Power Supply Rejection Ratio) improvement technique for the CSA design without power and area impact is proposed in this work. The analysis and equations of the proposed circuit are presented which were verified by electrical simulations and experimental test of a produced chip with 5 channels of the designed front-end. The measured equivalent noise charge was <550e for 30mV/fC of sensitivity at a input capacitance of 18.5pF. The total core area of the front-end was 2300?m × 150?m, and the measured total power consumption was 9.1mW per channel. / ALICE é um dos quatro grandes experimentos do acelerador de partículas LHC (Large Hadron Collider) instalado no laboratório europeu CERN. Um programa de atualizações desse experimento acaba de ser aprovado pelo comitê gestor do acelerador LHC. Dentro das atualizações planejadas para os próximos anos do experimento ALICE, está melhorar a resolução e eficiência de rastreamento de partículas produzidas em colisões entre íons pesados, mantendo a excelente capacidade de identificação de partículas para uma taxa de leitura de eventos significativamente maior da atual. Para se alcançar esse objetivo, entre outras ações, é preciso atualizar os detectores Time Projection Chamber (TPC), modificando a eletrônica de leitura de eventos, a qual não é adequada para esta migração. Para superar esta limitação tem sido proposto o projeto, simulação, fabricação, teste experimental e validação de um ASIC protótipo de aquisição de sinais e de processamento digital chamado SAMPA, que possa ser usado na eletrônica de detecção dos sinais no cátodo do TPC, que suporte polaridades negativas de tensão de entrada e leitura continua de dados, com 32 canais por chip, com menor consumo de potência comparado com a versão anterior do chip. Este trabalho tem como objetivo o projeto, fabricação, e teste experimental de um readout front-end em tecnologia CMOS 130nm, com polaridade configurable (positiva/ negativa), peaking time e sensibilidade, de forma que o novo SAMPA ASIC possa ser usada em ambos detectores. Para obter um ASIC integrando 32 canais por chip, o projeto do front-end proposto precisa ter baixa área e baixo consumo de potência, mas ao mesmo tempo requer baixo ruido. Neste sentido, uma nova técnica para melhorar a especificação de ruido e o PSRR (Power Supply Rejection Ratio) sem impacto no consumo de área e potência é proposta neste trabalho. A análise e as equações do circuito proposto são apresentadas as quais foram validadas por simulação e teste experimental de um circuito integrado com 5 canais do front-end projetado. O Equivalent Noise Charge medido foi <550e para uma capacitance do detector de 18.5pF. A área total do front-end foi de 2300?m × 150?m, e o consumo total de potencia medido foi de 9.1mW por canal.
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Visualização, kernels e subespaços: um estudo prático / Visualization, kernels and subspace: a practical studyBarbosa, Adriano Oliveira 16 December 2016 (has links)
Dados de alta dimensão são tipicamente tratados como pertencentes a um único subespaço do espaço onde estão imersos. Entretanto, dados utilizados em aplicações reais estão usualmente distribuídos entre subespaços independentes e com dimensões distintas. Um objeto de estudo surge a partir dessa afirmação: como essa distribuição em subespaços independentes pode auxiliar tarefas de visualização? Por outro lado, se o dado parece estar embaralhado nesse espaço de alta dimensão, como visualizar seus padrões e realizar tarefas como classificação? Podemos, por exemplo, mapear esse dado num outro espaço utilizando uma função capaz de o desembaralhar, de modo que os padrões intrínsecos fiquem mais claros e, assim, facilitando nossa tarefa de visualização ou classificação. Essa Tese apresenta dois estudos que abordam ambos os problemas. Para o primeiro, utilizamos técnicas de subspace clustering para definir, quando existente, a estrutura de subespaços do dado e estudamos como essa informação pode auxiliar em visualizações utilizando projeções multidimensionais. Para o segundo problema, métodos de kernel, bastante conhecidos na literatura, são as ferramentas a nos auxiliar. Utilizamos a medida de similaridade do kernel para desenvolver uma nova técnica de projeção multidimensional capaz de lidar com dados imersos no espaço de características induzido implicitamente pelo kernel. / High-dimensional data are typically handled as laying in a single subspace of the original space. However, data involved in real applications are usually spread around in distinct subspaces which may have different dimensions. We would like to study how the subspace structure information can be used to improve visualization tasks. On the other hand, what if the data is tangled in this high-dimensional space, how to visualize its patterns or how to accomplish classification tasks? One could, for example, map the data in another high-dimensional space using amapping capable of untangle the data making the patterns clear, rendering the visualization or classification an easy task. This dissertation presents an study for both problems pointed out above. For the former, we use subspace clustering techniques to define, when it exists, a subspace structure, studying how this information can be used to support visualization tasks based on multidimensional projections. For the latter problem we employ kernel methods, well known in the literature, as a tool to assist visualization tasks. We use a similarity measure given by the kernel to develop acompletely new multidimensional projection technique capable of dealing with data embedded in the implicit feature space defined by the kernel.
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Harnessing demographic data for cross-scale analysis of forest dynamicsNeedham, Jessica January 2016 (has links)
Forests are a critical biome but are under threat from unprecedented global change. The need to understand forest dynamics across spatial, temporal and biological scales has never been greater. Critical to this will be understanding how the demographic rates of individuals translate into patterns of species diversity, biomass and carbon turnover at much larger scales. In this thesis, I present a modelling framework focussed on demography. In Chapter 2, I introduce methods for translating forest inventory data into population models that account for the size-dependency of vital rates and persistent differences in individual performance. Outbreaks of forest pest and pathogens are increasing in frequency and severity, with consequences for biodiversity and forest structure. In Chapter 3, I explore the impact of ash dieback on the community dynamics of a British woodland, describing a spatially explicit individual based model that captures the effect of an opening of the canopy on local competitive interactions. Chapter 4 introduces methods to infer the impact of historical deer herbivory on the juvenile survival of forest trees. The approach is generalisable and could be applied to any forest in which patterns of regeneration and community structure have been impacted by periodic disturbance (e.g. forest fires). Finding meaningful ways of incorporating species diversity into global vegetation models is increasingly recognised as a research priority. In Chapter 5, I explore the diversity of demographic rates in a tropical forest community and identify groups of species with similar life history strategies. I discuss the potential of integrating demographic and physiological traits as a way to aggregate species for inclusion in global models. In summary, translating measurements of individuals into population dynamics provides opportunities to both explore small-scale community responses to disturbance events, and to feed into much larger scale vegetation models.
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Inventários do impalpável : uma coleção de sombras, temporalidades e projeçõesMadsen, Larissa January 2010 (has links)
O presente texto - Inventários do Impalpável: uma coleção de sombras, temporalidades e projeções -, resultado de pesquisa em poéticas visuais, tem como foco principal a análise de meu percurso artístico no qual a sombra foi o principal elemento constituinte. Interessa-me pensar na qualidade da imagem que, se por um lado fixa um momento, por outro lado remete ao movimento, à passagem do tempo e à sua fluidez: o tempo suspenso ou o tempo acumulado, mas sempre a passagem, o devir e o tempo. Por meio de desenhos e de fotografias realizo escrituras temporais. Durante a pesquisa, interessou-me ainda observar como se dá a percepção do tempo-espaço a partir de projeções e investigar, por meios plásticos, a operacionalidade de sua visualidade. O texto está ancorado em três conceitos implicados no processo artístico: temporalidade, materialidade e colecionismo. / This text, – Impalpable Inventories: a collection of shadows, temporalities and projections - the result of research into visual poetry is focused on an analysis of my artistic career in which shadow was the main constituent element. Interests me to think about the image quality which, if on one hand fixes a moment, on the other hand refers to movement, the passage of time and its fluidity: the suspended time or cumulative time, but always in transition, the becoming and the time. Through drawings and photographs I perform temporal scriptures. During the research, I was also interested in observing how the perception of space-time takes place from projections and investigate, by plastic means, the operation of its visuality. The text is anchored on three concepts involved in the artistic process: temporality, materiality and hoarding.
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Alternativní využití Szondiho testu / Alternative use of Szondi testVaňková, Martina January 2012 (has links)
The thesis analyzes the Szondi's test and its theory in the light of current knowledge. Its aim is to examine the potential of this diagnostic method and to consider the possibilities of its application. On the basis of the free-association research, the direction of interest has divided into two studies. The first of them verifies the relationship of Szondi's theory with personal characteristics that are attributed to individual photos (stimulus material) on the scale of the semantic differential. In most cases, the results confirm significant differences between the factors. In the second study, the narrative approach is selected, it means "telling stories" method will be used for discover the projective potential. Qualitative analysis indicates that stories have some similarities- in the context of given factors, however, in most cases, they do not follow Szondi's assumptions. In order to confirm the potential of the possibility to know the proband's personality or life, the data obtained has not proved sufficient. The data does suggest, however, that after further research, the benefit of its application could be confirmed. KEY WORDS: Szondi test, projection, semantic differential, stories analysis
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