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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
11

Caracterização do vento e estimativa do potencial eólico para a região de tabuleiros costeiros (Pilar, Alagoas) / Wind characterization and aeolian potential estimate to the coastal region (Pilar, Alagoas)

Silva, Juliane Kayse Albuquerque da 15 June 2007 (has links)
The aim of this study was to characterize the wind behavior (velocity, direction, turbulence index and gust factor), as well as a preliminary estimate of the aeolian potential in coastal region close to Maceió. The wind data utilized was collected during the MICROMA project (Micrometeorologia da Mata Atlântica Alagoana) installed at Vilanova Farm, Pilar Alagoas State (9º36 12 S, 35º53 46 W, 170 m), from July/1996 to September/1999. The results showed that the local wind is influenced by micro and macro scale phenomenon. The wind velocity (8,29m height) decreases in the winter and increases in the summer. In the two seasons the wind velocity is faster during daytime. Almost in a half of the case (46%) the wind velocity is between zero and 2,0 m.s-1. The wind direction showed a little variability and the predominant flow is from ocean to continent felt (66%). The behavior of the atmospheric turbulence is inverse to the wind velocity. The wind velocity (estimated to 75m height) in 99,5% of the cases was superior to the initial velocity to start the aero generator (2,5 m.s-1). The simulated average wind power potential value was 110,27±106,51 W.m-2. / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Este trabalho teve como objetivo a caracterização do comportamento do vento (velocidade, direção, índice de turbulência e fator de rajadas), bem como fazer uma estimativa preliminar do potencial eólico para a região de tabuleiros costeiros próximo a Maceió. Foram utilizados os dados de vento coletados durante a realização do projeto MICROMA (Micrometeorologia da Mata Atlântica Alagoana) montado na Fazenda Vilanova, Pilar AL (9º36 12 S, 35º53 46 W, 170 m), no período de julho de 1996 a setembro de 1999. Os resultados mostraram que o vento no local é influenciado pelos fenômenos locais e os de grande escala. A velocidade (8,29 m) diminui no inverno e aumenta no verão, e, em ambas as estações, é bem maior durante o dia. Quase metade (46%) dos casos são ventos na faixa de zero até 2,0 m.s-1. A direção apresenta pouca variabilidade e o fluxo predominante é no sentindo oceano-continente (66%). A turbulência atmosférica é inversamente proporcional a velocidade do vento. O vento estimado para 75m em 99,5% dos casos foi superior a velocidade de partida dos aerogeradores (2,5 m.s-1). O valor médio estimado para o potencial eólico foi de 110,27±106,51 W.m-2 com maior ocorrência na faixa entre 50-100 W.m-2 (38,6%).
12

AnÃlise de campos de ventos oceÃnicos em imagens SAR / ANALYSIS OF OCEAN WINDS FIELDS IN IMAGES SAR

Gladeston da Costa Leite 26 September 2011 (has links)
FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgico / Esta tese introduz uma nova metodologia para determinar a direÃÃo do vento sobre a superfÃcie dos oceanos utilizando tÃcnicas de processamento das imagens de Radar de Abertura SintÃtica (SAR, do inglÃs Synthetic Aperture Radar). A literatura relacionada demonstra um crescente interesse no processamento dessas imagens para detecÃÃo de alvos, classificaÃÃo de regiÃes, extraÃÃo de campos de ventos, monitoramento de derrames de Ãleo, aplicaÃÃes geofÃsicas e meteorolÃgicas. A extraÃÃo de campos de ventos em imagens SAR à uma tarefa desafiadora devido à contaminaÃÃo das mesmas por um ruÃdo oriundo do sistema de aquisiÃÃo, denominado speckle, que dificulta tarefas de processamento e interpretaÃÃo das mesmas. Portanto, esta tese propÃe metodologias de extraÃÃo da direÃÃo do vento por transformada de Fourier, transformadas wavelets e mÃtodos baseados em textura. As transformadas wavelets utilizadas para esta tarefa sÃo Gabor, ChapÃu Mexicano e o algoritmo à trous. Com relaÃÃo à anÃlise de textura utilizada, esta se baseia na informaÃÃo espacial da matriz de co-ocorrÃncia dos nÃveis de cinza para estimar a direÃÃo de padrÃes lineares em imagens contaminadas com speckle. Os experimentos foram realizados em imagens de textura sintÃticas, imagens do Ãlbum de Brodatz e imagens SAR sintÃticas e reais. Foi observado que os mÃtodos propostos foram capazes de estimar direÃÃes de padrÃes lineares e extrair campos de streaks de vento visÃveis em imagens SAR reais. As principais contribuiÃÃes desta tese sÃo: o mÃtodo proposto para estimaÃÃo de direÃÃo de ventos na superfÃcie do oceano e a extensÃo de tÃcnica jà existente na literatura, possibilitando assim a estimaÃÃo da velocidade dos ventos na faixa de 4 a 10 m/s. Os melhores resultados obtidos nesta tese foram alcanÃados utilizando o mÃtodo proposto que combina transformada wavelet e anÃlise de textura. / This thesis introduces a new methodology to determine the wind direction over the ocean surface using image processing techniques on SAR (Synthetic Aperture Radar) images. Related literature demonstrates a growing interest in processing these images for target detection, region classification, wind field extraction, oil spill monitoring, geophysical and meteorological applications. Wind field extraction in SAR images is a challenging task due to contamination acquisition system by speckle noise, which makes difficult processing and interpretation tasks. Thus, this thesis proposes methods for wind direction estimation by applying image transforms, such as Fourier and wavelets and furthermore texture-based methods. The wavelet transforms used for this task are Gabor, Mexican Hat and the à trous algorithm. Concerning the texture approach, it is based on the co-occurrence matrix to estimate direction of linear patterns in speckled images. The experiments were performed on synthetic texture, Brodatz album, synthetic and real SAR images. It was observed that the proposed methods were able to estimate directions of linear patterns and extract wind fields from visible wind-induced streaks on SAR images. The main contributions of this thesis are: to propose methods for wind direction estimation on the ocean surface and to extend existing techniques in the literature in order to provide wind vector estimation in the range of 4 to 10 m/s. The best results of this tese were achieved with the proposed method that combines wavelet transform and texture analysis.
13

Vyhodnocení spotřeby osobní lodi / Passenger vessel consumption computation

Drbohlav, Lukáš January 2012 (has links)
This thesis is focused on a design and an implementation of a power consumption computation for a passenger vessel using the industrial automation system Siemens Simatic S7-200 and the touch panel Weintek Easy View MT8150X. A part of the thesis represents a theoretical summary of features and parametres of the programmable logic controllers (PLC) and a way how they are programmed. The work includes a description of a computational algorithm, a block diagram of interconnections and a visualization software for testing. A greater part of this publication is devoted to a detailed decription of a program in the PLC and its visualization, especially the power consumption computation, a distance, an average speed and a wind speed and a direction. At the end, the thesis shows a procedure for an implementation and a measurement on the passenger ships at the Brno dam, including an evaluation of downloaded data.
14

Meteostanice / Weather Station

Beneděla, Pavel January 2013 (has links)
This thesis deals with conception of proposal and implementation of a weather station. Weather station is composed of three main parts which are measuring station, showing station and USB wireless receiving module. Measuring station measures basic meteorologic variables and sends measured variables through wireless communication. Showing station is designed to present measured data with graphics user interface and generate data for a web server.
15

Investigations of GNSS-R for Ocean Wind, Sea Surface Height, and Land Surface Remote Sensing

Park, Jeonghwan January 2017 (has links)
No description available.
16

Meteorologiska mätningar med drönare / Meteorological measurements with drones

Greenland, Christopher January 2019 (has links)
Studien handlade om att belysa hur UAV:s kan komma till nytta i meteorologisk forskning och att ta reda på hur bra drönare är på att mäta meteorologiska storheter. Drönare, som också kallas UAV:s (Unmanned Aerial Vehicle) är mindre obemmanade luftfartyg som kan flyga autonomt eller fjärrstyras. Idag används drönare alltmer i meteorologi vilket beror mycket på den tekniska utvecklingen. Exempel på meteorologiska applikationer är mätning av vindhastighet och koncentrationen av koldioxid i luften som kan användas för att studera de lägsta atmosfäriska skikten. Storheter som mättes i detta projekt var vindhastighet, vindriktning, temperatur och relativ fuktighet på olika höjder. Mätningarna gjordes två gånger i en mätstation i Marsta, som ligger utanför Uppsala. Efteråt jämfördes datan från drönaren med data från en instrumenterad mast vid väderstationen. Resultaten visade att drönarens vindprofiler stämde ganska väl överens med mastens vindprofiler och den logaritmiska vindlagen. Under den första fältmätningen uppskattade drönaren att vindhastigheten var 8.13 ± 1.33 m/s vid hovring på tio meters höjd medan masten angav 8.41 ± 0.958 m/s. Drönarens mätvärden för vindriktningen var ibland bra och ibland mindre bra. Mätvärdena för temperaturen och den relativa fuktigheten avvek med upp mot 1 ◦C respektive 10 procentenheter. / The aim of this report was to study how UAV:s can be applied in meteorological research and find out how good drones are at measuring meteorological parameters. A drone, also known as an UAV (Unmanned Aerial Vehicle) is a smaller unmanned aircraft that can fly autonomously or under remote control. Today, drones are used more frequently in meteorology, mostly due to the recent technological development. Examples of meteorological applications include measurements of wind speed and the amount of carbon dioxide in the air which can be used to analyze the lower parts of the atmosphere. In this project, the wind speed and its direction, the temperature and the relative humidity were measured at different heights. The measurements took place twice in Marsta which is a field station outside Uppsala. Then, the data from the drone was compared to the data from a weather tower at the instrumented station. The results showed that the drone’s wind profiles were relatively similar to the profiles according to the tower and the logarithmic wind profiles. For instance, during the first flight the drone estimated the wind speed to be 8.13 ± 1.33 m/s while hovering ten metres above the ground. The tower measured 8.41 ± 0.958 m/s at the same height. The drone’s estimations of the wind direction were sometimes accurate and sometimes not accurate. The temperature and relative humidity however was different by 1 ◦C and ten percentage units respectively.
17

Black Guillemots as indicators of change in the near-shore Arctic marine ecosystem

Harter, B. Britten 14 September 2007 (has links)
This study attempted to explain an apparent inverse relationship between pack ice proximity and breeding success of Black Guillemots (Cepphus grylle) on Cooper Island, a barrier island in the western Beaufort Sea near Barrow, AK. I elucidated the first linear relationship between energy density and body size for the elusive Arctic Cod (Boreogadus saida). I discovered and ground-truthed the existence of previously unknown guillemot foraging habitat on small 50 m2 ice floes distant from the pack ice. I developed new daily metrics for quantifying the provisioning to linear (8 d – 18 d) and Post-Linear (19 d – fledge) chicks. I found daily consensus between Linear and Post-Linear chicks about the level of provisioning at the colony. Finally, I explained those daily changes with significant correlations with wind speed and direction. / October 2007
18

Black Guillemots as indicators of change in the near-shore Arctic marine ecosystem

Harter, B. Britten 14 September 2007 (has links)
This study attempted to explain an apparent inverse relationship between pack ice proximity and breeding success of Black Guillemots (Cepphus grylle) on Cooper Island, a barrier island in the western Beaufort Sea near Barrow, AK. I elucidated the first linear relationship between energy density and body size for the elusive Arctic Cod (Boreogadus saida). I discovered and ground-truthed the existence of previously unknown guillemot foraging habitat on small 50 m2 ice floes distant from the pack ice. I developed new daily metrics for quantifying the provisioning to linear (8 d – 18 d) and Post-Linear (19 d – fledge) chicks. I found daily consensus between Linear and Post-Linear chicks about the level of provisioning at the colony. Finally, I explained those daily changes with significant correlations with wind speed and direction.
19

Black Guillemots as indicators of change in the near-shore Arctic marine ecosystem

Harter, B. Britten 14 September 2007 (has links)
This study attempted to explain an apparent inverse relationship between pack ice proximity and breeding success of Black Guillemots (Cepphus grylle) on Cooper Island, a barrier island in the western Beaufort Sea near Barrow, AK. I elucidated the first linear relationship between energy density and body size for the elusive Arctic Cod (Boreogadus saida). I discovered and ground-truthed the existence of previously unknown guillemot foraging habitat on small 50 m2 ice floes distant from the pack ice. I developed new daily metrics for quantifying the provisioning to linear (8 d – 18 d) and Post-Linear (19 d – fledge) chicks. I found daily consensus between Linear and Post-Linear chicks about the level of provisioning at the colony. Finally, I explained those daily changes with significant correlations with wind speed and direction.
20

Využití univerálního modulu LabJack\hindex{TM} pro podporu výuky fyziky / Application versatile module LabJack\hindex{TM} in education of physics

PŘIBYL, Vojtěch January 2012 (has links)
Theme of this thesis is using of universal module LabJack U3-HVTM as support for physics lessons. This thesis describes the universal module LabJack U3-HVTM and evaluation method of measured value on the computer screen using software eSimLab. To all physical tasks is described path of signal with measured string from developed sensor until evaluation of signal in the computer. In the thesis is specifically described a function of developed sensors of physical quantities, there are subscribed diagrams including PCB and parts list. The thesis is including designed physical tasks for monitoring of atmospheric pressure, temperature, wind direction, sunshine duration and the role of measurement of the signal on the optical transmitter using the developed sensors and universal module LabJack U3-HVTM.

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