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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.
21

Determinação da temperatura retal e frequência respiratória de suínos em fase de creche por meio da temperatura da superfície corporal em câmara climática / Determination of piglet\'s rectal temperature and respiratory rate through body surface temperature in a climatic chamber

Mostaço, Gustavo Marques 10 April 2014 (has links)
A constante influência humana em atividades de manejo animal, além de aumentar os custos de produção, torna-se uma adicional fonte geradora de estresse sobre os animais. Nesse sentido, é necessária a busca pelo desenvolvimento de métodos alternativos de acompanhamento, à distância e em tempo real, das condições físicas dos animais, em conjunto com o controle das instalações. Para a identificação da condição de conforto ou estresse calórico dos animais, alguns indicativos podem vir a auxiliar, tais como a temperatura retal (TR), sendo esse um bom indicador da temperatura do núcleo corporal, bem como, a frequência respiratória (FR). Porém, com a crescente preocupação em relação ao bem-estar animal, vários questionamentos são feitos acerca de métodos invasivos, motivando a busca por alternativas à mensuração da TR. Surge então, como variável alternativa, a temperatura da superfície corporal, buscando-se correlacioná-la com a TR e FR. Sendo assim, com essa pesquisa objetivou-se identificar a região mais adequada da superfície corporal dos suínos, em fase de creche, que apresente a melhor correlação com a TR e FR. Para tal, foi conduzido um experimento, dividido em duas etapas: etapa 1) pré-experimento, sendo conduzido com dois animais em câmara climática, variando-se as condições de temperatura e testando-se métodos de fixação de sensores e coleta de dados inicialmente propostos; e etapa 2) experimento principal. Este último foi conduzido em uma câmara climática, com cinco leitões da raça Landrace x Large White, com 30 dias de idade, provenientes de uma mesma ninhada e do mesmo sexo (fêmea). Variaram-se as condições de temperatura no interior da câmara climática de 14°C a 35,5°C, de modo a atingir situações de estresse tanto por frio quanto por calor, sendo calculada a entalpia para os propósitos do presente estudo. O delineamento estatístico utilizado foi o inteiramente casualizado, com um único fator, a entalpia ambiente, com sete níveis (31,26; 39,56; 51,12; 59,24; 74,82; 82,96; 94,26 kJ.kg de ar seco-1). Foram realizadas medidas repetidas em intervalos de 30 minutos, em seis diferentes regiões corporais: cabeça (A), paleta (B), lombo (C), pernil (D), orelha (E) e timpânica (F). Para as regiões de A a E foram utilizados dois métodos de medida diferentes: datalogger de temperatura Thermochron iButton® - DS1921G e outro via termômetro de infravermelho Fluke® 566. Para a região F, utilizou-se um termômetro de infravermelho de testa e ouvido G-Tech - T1000. Todos com cinco repetições das medidas para cada variável, em cada situação ambiente. Com os resultados obtidos foi possível propor equações de regressão múltipla para a TR e FR, sendo esta última apontada pela análise de componentes principais como a melhor candidata a correlações com as temperaturas da superfície corporal e por ser um bom indicador da situação de estresse térmico. Por meio desses resultados foi possível observar que a região timpânica mostrou-se como a melhor opção para acompanhamento tanto da TR quanto da FR via termômetro de infravermelho (TiF), enquanto que ao utilizar sensores de temperatura da superfície corporal, a melhor opção foi a orelha (TbE) para predição de TR, e a região do lombo (TbC) para predição de FR. / Human constant influence in handling activities, besides raising production costs, becomes another stress source for the animals. In this sense, it becomes necessary the development of alternative methods, that can remotely monitor, in real time, animal\'s physical conditions, together with remote facilities control. In terms of identifying comfort or stressful thermal situations for animals, some indicators can be handy, such as rectal temperature (RT), which is a good indicator of the core body temperature, as well as, the respiratory rate (RR). Although, with the raising concerns about animal welfare, several questions are raised against invasive methods, encouraging the search for alternatives to RT measuring. The determination of body surface temperature values, trying to correlate them to RT and RR, emerges as an alternative. Thus, it\'s aimed, with this research, to identify the most adequate swine body surface region, in nursery phase, which presents better correlation with RT and RR. For that, an experiment was conducted, divided in two stages: stage 1) pre-experiment, being conducted with two animals in a climate chamber, varying temperature conditions and testing sensor fixation and data collection methods previously proposed; and stage 2) main experiment. The last one was conducted in a climate chamber, with five Landrace x Large White piglets, 30 days aged, from the same litter and of the same sex (female). Temperature conditions inside the chamber were varied from 14°C to 35.5°C, attaining stressful situations both for cold and heat, being calculated the enthalpy for this study purposes. The statistical design used was the completely randomized, with one factor only, the ambient enthalpy, in seven levels (31.26; 39.56; 51.12; 59.24; 74.82; 82.96; 94.26 kJ.kg of dry air-1). Repeated measures were taken in 30 minutes intervals, in six different body regions: head (A), shoulder (B), loin (C), ham (D), ear (E) and tympanic (F). For regions from A to E, two different methods were used: temperature datalogger Thermochron iButton® - DS1921G and infrared thermometer Fluke® 566. For region F, a forehead and ear infrared thermometer G-Tech - T1000 was used. All of them had five replicates of measures for each variable, in each environment situation. With the obtained data, it was possible to propound multiple regression equations for RT and RR, the last one being shown by principal components analysis as a better candidate to correlate to body surface temperatures and because it\'s a good indicator of the animal\'s thermal stress situation. By means of these results it was possible to observe that the tympanic region arises as the better option for monitoring RT and RR through infrared thermometer (TiF), while when using body surface temperature sensors, the best option was the ear (TbE) for predicting RT, and the loin region (TbC) for predicting RR.
22

OBTENÇÃO DE COMPOSIÇÕES CERÂMICAS Mn-Ni-Co VIA SÍNTESE POR LIOFILIZAÇÃO E SUA CARACTERIZAÇÃO ELÉTRICA COMO SENSOR DE TEMPERATURA.

Silva, Edson José Lima da 22 December 2011 (has links)
Made available in DSpace on 2017-07-21T20:42:36Z (GMT). No. of bitstreams: 1 EDSON JOSE LIMA DA SILVA.pdf: 3364047 bytes, checksum: 8d0d1391435837a4f603477a06c59876 (MD5) Previous issue date: 2011-12-22 / This work describes the preparation of nanoparticles of spinel structure, made from oxides of Manganese, Nickel and Cobalt, via lyophilization process, which was compared to the process of obtaining conventional mixture of oxides, in order to analyze different forms of preparation and its influence on electrical properties (characteristic resistance, temperature coefficient, stability of the thermistor), through the measures obtained by applying a voltage of 5 volts on pads and subjecting them to a temperature range of 20 C to 300 C, measured with a thermocouple type K The microstructures were analyzed by scanning electron microscopy (SEM), the average particle size ranged from 60 to 93 nm. X-ray spectroscopy to determine the phases present in the samples and analysis of infrared to identify in the process, organic waste and the organic phase transitions were completely volatilized during the controlled heating pad on high-temperature furnace (with resistance molybdenum silicide) (Lindenberg). Through the obtained results it was noted a certain advantage at all temperatures of the samples had the composition Ni Mn and Co on the Mn Ni which had only giving larger values between 4335 and 4571 for samples made from the process liofilization. / Este trabalho descreve a preparação de nanoparticulas de estrutura espinélio, feitas a partir de óxidos de Manganês, Níquel e Cobalto, via processo de liofilização, o qual foi comparado ao processo de obtenção convencional, mistura de óxidos, afim de se analisar diferentes formas de preparação e sua influência nas propriedades elétricas (resistência característica, coeficiente de temperatura, estabilidade do termistor), através das medidas obtidas aplicando-se uma tensão de 5 volts nas pastilhas e submetendo-as a uma variação de temperatura de 20C a 300C, aferidos com um termopar tipo K. As Microestruturas foram analisadas por microscopia eletrônica de varredura (MEV), o tamanho médio das partículas ficaram entre 60 a 93 nm. Espectroscopia de raios X para determinação das fases presentes nas amostras e análise de infravermelho para se identificar em que fase do processo os resíduos orgânicos e as transições de fases orgânicas foram totalmente volatilizados ao longo do aquecimento controlado das pastilhas em forno de alta temperatura (com resistência de siliceto de molibdênio) (Lindenberg). Através dos resultados obtidos notou-se uma certa vantagem em todas as temperaturas das amostras que tinham na composição Mn Ni e Co sobre as que tinham apenas Mn Ni dando valores de maiores, entre 4335 e 4571 para as amostras feitas a partir do processo de liofilização.
23

Determinação da temperatura retal e frequência respiratória de suínos em fase de creche por meio da temperatura da superfície corporal em câmara climática / Determination of piglet\'s rectal temperature and respiratory rate through body surface temperature in a climatic chamber

Gustavo Marques Mostaço 10 April 2014 (has links)
A constante influência humana em atividades de manejo animal, além de aumentar os custos de produção, torna-se uma adicional fonte geradora de estresse sobre os animais. Nesse sentido, é necessária a busca pelo desenvolvimento de métodos alternativos de acompanhamento, à distância e em tempo real, das condições físicas dos animais, em conjunto com o controle das instalações. Para a identificação da condição de conforto ou estresse calórico dos animais, alguns indicativos podem vir a auxiliar, tais como a temperatura retal (TR), sendo esse um bom indicador da temperatura do núcleo corporal, bem como, a frequência respiratória (FR). Porém, com a crescente preocupação em relação ao bem-estar animal, vários questionamentos são feitos acerca de métodos invasivos, motivando a busca por alternativas à mensuração da TR. Surge então, como variável alternativa, a temperatura da superfície corporal, buscando-se correlacioná-la com a TR e FR. Sendo assim, com essa pesquisa objetivou-se identificar a região mais adequada da superfície corporal dos suínos, em fase de creche, que apresente a melhor correlação com a TR e FR. Para tal, foi conduzido um experimento, dividido em duas etapas: etapa 1) pré-experimento, sendo conduzido com dois animais em câmara climática, variando-se as condições de temperatura e testando-se métodos de fixação de sensores e coleta de dados inicialmente propostos; e etapa 2) experimento principal. Este último foi conduzido em uma câmara climática, com cinco leitões da raça Landrace x Large White, com 30 dias de idade, provenientes de uma mesma ninhada e do mesmo sexo (fêmea). Variaram-se as condições de temperatura no interior da câmara climática de 14°C a 35,5°C, de modo a atingir situações de estresse tanto por frio quanto por calor, sendo calculada a entalpia para os propósitos do presente estudo. O delineamento estatístico utilizado foi o inteiramente casualizado, com um único fator, a entalpia ambiente, com sete níveis (31,26; 39,56; 51,12; 59,24; 74,82; 82,96; 94,26 kJ.kg de ar seco-1). Foram realizadas medidas repetidas em intervalos de 30 minutos, em seis diferentes regiões corporais: cabeça (A), paleta (B), lombo (C), pernil (D), orelha (E) e timpânica (F). Para as regiões de A a E foram utilizados dois métodos de medida diferentes: datalogger de temperatura Thermochron iButton® - DS1921G e outro via termômetro de infravermelho Fluke® 566. Para a região F, utilizou-se um termômetro de infravermelho de testa e ouvido G-Tech - T1000. Todos com cinco repetições das medidas para cada variável, em cada situação ambiente. Com os resultados obtidos foi possível propor equações de regressão múltipla para a TR e FR, sendo esta última apontada pela análise de componentes principais como a melhor candidata a correlações com as temperaturas da superfície corporal e por ser um bom indicador da situação de estresse térmico. Por meio desses resultados foi possível observar que a região timpânica mostrou-se como a melhor opção para acompanhamento tanto da TR quanto da FR via termômetro de infravermelho (TiF), enquanto que ao utilizar sensores de temperatura da superfície corporal, a melhor opção foi a orelha (TbE) para predição de TR, e a região do lombo (TbC) para predição de FR. / Human constant influence in handling activities, besides raising production costs, becomes another stress source for the animals. In this sense, it becomes necessary the development of alternative methods, that can remotely monitor, in real time, animal\'s physical conditions, together with remote facilities control. In terms of identifying comfort or stressful thermal situations for animals, some indicators can be handy, such as rectal temperature (RT), which is a good indicator of the core body temperature, as well as, the respiratory rate (RR). Although, with the raising concerns about animal welfare, several questions are raised against invasive methods, encouraging the search for alternatives to RT measuring. The determination of body surface temperature values, trying to correlate them to RT and RR, emerges as an alternative. Thus, it\'s aimed, with this research, to identify the most adequate swine body surface region, in nursery phase, which presents better correlation with RT and RR. For that, an experiment was conducted, divided in two stages: stage 1) pre-experiment, being conducted with two animals in a climate chamber, varying temperature conditions and testing sensor fixation and data collection methods previously proposed; and stage 2) main experiment. The last one was conducted in a climate chamber, with five Landrace x Large White piglets, 30 days aged, from the same litter and of the same sex (female). Temperature conditions inside the chamber were varied from 14°C to 35.5°C, attaining stressful situations both for cold and heat, being calculated the enthalpy for this study purposes. The statistical design used was the completely randomized, with one factor only, the ambient enthalpy, in seven levels (31.26; 39.56; 51.12; 59.24; 74.82; 82.96; 94.26 kJ.kg of dry air-1). Repeated measures were taken in 30 minutes intervals, in six different body regions: head (A), shoulder (B), loin (C), ham (D), ear (E) and tympanic (F). For regions from A to E, two different methods were used: temperature datalogger Thermochron iButton® - DS1921G and infrared thermometer Fluke® 566. For region F, a forehead and ear infrared thermometer G-Tech - T1000 was used. All of them had five replicates of measures for each variable, in each environment situation. With the obtained data, it was possible to propound multiple regression equations for RT and RR, the last one being shown by principal components analysis as a better candidate to correlate to body surface temperatures and because it\'s a good indicator of the animal\'s thermal stress situation. By means of these results it was possible to observe that the tympanic region arises as the better option for monitoring RT and RR through infrared thermometer (TiF), while when using body surface temperature sensors, the best option was the ear (TbE) for predicting RT, and the loin region (TbC) for predicting RR.
24

Seebeck coefficient in organic semiconductors

Venkateshvaran, Deepak January 2014 (has links)
When a temperature differential is applied across a semiconductor, a thermal voltage develops across it in response. The ratio of this thermal voltage to the applied temperature differential is the Seebeck coefficient, a transport coefficient that complements measurements of electrical and thermal conductivity. The physical interpretation of the Seebeck coefficient is the entropy per charge carrier divided by its charge and is hence a direct measurement of the carrier entropy in the solid state. This PhD thesis has three major outcomes. The first major outcome is a demonstration of how the Seebeck coefficient can be used as a tool to quantify the role of energetic disorder in organic semiconductors. To this end, a microfabricated chip was designed to perform accurate measurements of the Seebeck coefficient within the channel of the active layer in a field-effect transistor (FET). When measured within an FET, the Seebeck coefficient can be modulated using the gate electrode. The extent to which the Seebeck coefficient is modulated gives a clear idea of charge carrier trapping and the distribution of the density of states within the organic semiconductor. The second major outcome of this work is the observation that organic semiconducting polymers show Seebeck coefficients that are temperature independent and strongly gate voltage modulated. The extent to which the Seebeck coefficient is modulated in the polymer PBTTT is found to be larger than that in the polymer IDTBT. Taken together with conventional charge transport measurements on IDTBT, the voltage modulated Seebeck coefficient confirms the existence of a vanishingly small energetic disorder in this material. In the third and final outcome of this thesis, the magnitude of the Seebeck coefficient is shown to be larger for organic small molecules as compared to organic polymers. The basis for this is not yet clear. There are reports that such an observation is substantiated through a larger contribution from vibrational entropy that adds to the so called entropy-of-mixing contribution so as to boost the magnitude of the Seebeck coefficient in organic small molecules. As of now, this remains an open question and is a potential starting point for future work. The practical implications of this PhD thesis lie in building cost-effective and environmentally friendly waste-heat to useful energy converters based on organic polymers. The efficiency of heat to energy conversion by organic polymers tends to be higher than that for conventional semiconductors owing to the presence of narrow bands in organic polymer semiconductors.
25

Système d'interrogation à distance de grandeurs physiques à base de capteurs à ondes élastiques de surface pour mesures paramétriques sur une gamme de température étendue (-196 / +650ºC) / Wireless surface acoustic wave (SAW) interrogation system for parametric measurement on an extended temperature range

Droit, Christophe 10 September 2013 (has links)
Ce mémoire présente l’étude et la conception d’électroniques d’interrogation de capteurs passifs de grandeurs physiques à base d’ondes élastiques se propageant à la surface de matériaux (SAW) piézoélectriques mono-cristallins. L’objectif consiste à réaliser une électronique d’interrogation capable de sonder la réponse d’un résonateur SAW au travers d’une liaison radiofréquence (RF) sans fils pour en extraire une information de température. [...] Les électroniques présentées dans ce manuscrit fonctionnent sur l’analyse de la puissance rétro-diffusée par le capteur en s’inspirant de l’architecture d’un analyseur de réseau à balayage de fréquence. Deux électroniques d’interrogation sont présentées. La première utilise une synthèse de fréquence directe. La souplesse de générer un signal RF pour exciter le résonateur a donnée naissance à divers algorithmes pour optimiser les performances de la mesure. La vitesse à laquelle le lecteur est capable de sonder le capteur permet l’interrogation de capteurs placés sur un support mobile (axe de moteur). La résolution de mesure obtenue atteint le dixième de degré Celsius. La seconde électronique vise à réaliser une électronique compacte dans le but de réduire le nombre et la consommation des composants en intégrant les chaînes d’émission et de réception. Cette électronique est construite autour d’un radio-modem : ce composant combinant fonctionnalités RF et numériques est détourné de sa fonction principale de communication numérique dansle but d’interroger un résonateur SAW. Les contraintes associées aux constantes de temps,à l’isolation nécessaire et à l’accès à l’étage de réception d’un radio-modem nécessitent une étude préalable approfondie. L’algorithme développé pour ce composant a nécessité l’utilisation de techniques de traitement RADAR pour obtenir la température résultante d’un capteur différentiel bi -résonateurs. Cette électronique a permis de mesurer une température / This report deals with the study and design of interrogation electronics for probing surface acoustic wave (SAW) transducers used as passive wireless sensors of physical quantities.The basic principle is to develop hardware aimed at probing the response of SAW resonators through a radiofrequency wireless link in order to extract a temperature information. Resonators whose operating frequency is centered on the 433.92 MHz ISM band are developed as part oft he SAWHOT project aimed at measuring high (650 oC) temperatures. SAW resonators load energy when stimulated at resonance frequency. Upon stopping emission, this power is returned as a radiofrequency signal. The presented electronic systems operate on the analysis of thepower returned by the sensor, based on a frequency-sweep network analyzer architecture. Twointerrogation units are presented. The former is based on a Direct Digital Synthesis frequency source : the flexibility of this digital approach allows for probing resonating sensors followings everal algorithms meeting various constraints including measurement speed and resolution.Sub-millisecond interrogation resonance frequency identification is compatible with probingthe response of sensors located on mobile targets such as a rotating motor axis. The achieved resolution lies in the 0.1 oC range. The latter approach aims at designing a compact readerwith a reduced number of components, including all the elements of the interrogation chain,and hence a lower power consumption. This approach is based around integrated, single chip,radiomodems : this components combines radiofrequency and digital functionalities and is diverted from its original digital communication purpose for probing SAW sensors. Timing andisolation constraints as well as accessing the analog receiver stage require a dedicated analysis of the functionalities of the various available chips[...]
26

Caracterização da sensibilidade de fibras de cristal fotônico à pressão e temperatura para aplicações em sensoriamento

Oliveira, Rafael Euzebio Pereira de 13 May 2010 (has links)
Made available in DSpace on 2016-03-15T19:38:17Z (GMT). No. of bitstreams: 1 Rafael Euzebio Pereira de Oliveira.pdf: 3969043 bytes, checksum: cfa66f3e9f3a18e9e86b364cd01a2c0a (MD5) Previous issue date: 2010-05-13 / In this dissertation the transmission properties of photonic crystal fibers are assessed under the influence of pressure and temperature for sensing applications. A review is given of the light propagation in conventional optical fibers and the effects of pressure and temperature on the refractive index of silica are studied. Photonic crystals in 1 and 2 dimensions are also studied. Then, microstructured fibers and photonic crystal fibers are addressed and their guidance properties and general applications are shown. A review is made of temperature and pressure sensors based on conventional fibers, Bragg gratings and microstructured and photonic crystal fibers described in the literature. Finally, results are shown and discussed of the experiments with the application of pressure on a hollow-core photonic crystal fiber, for which high-order bandgaps, in the visible spectral region, were identified and characterized for the first time. These bandgaps are shown to be pressure sensitive. Applying external hydrostatic pressure over the fiber, optical transmission variations of a few dB were observed for pressures of hundreds of kgf/cm², while when the fiber holes were internally pressurized a similar variation was achieved for units of kgf/cm². The response of light polarization, and hence of the fiber birefringence, to internal pressure was also analyzed.. In the other part of the experimental work, the temperature-induced bandgap spectral shift of photonic bandgap fibers was characterized. The response of a hollow-core fiber, a hybrid fiber and an all-solid fiber was characterized with bandgap shifts of up to 36 pm/°C in straight fibers. For the all-solid fiber the influence of bending over the bandgaps was characterized, as well as temperature-induced bandgaps shifts under these conditions. For a straight fiber, a simple model for the bandgap shift calculation is presented and showed good agreement with the experimental results. Closing the work, the conclusions are presented. / Nessa dissertação são avaliadas as propriedades de transmissão em fibras de cristal fotônico sob influência da pressão e da temperatura visando aplicações em sensoriamento. Antes é feita uma revisão da propagação da luz em fibras ópticas convencionais e os efeitos da pressão e temperatura sobre o índice de refração da sílica. Também são estudados os cristais fotônicos em 1 e 2 dimensões. Em seguida são estudadas as fibras microestruturadas e de cristal fotônico e são mostradas suas propriedades de guiamento e aplicações gerais. Em seguida é mostrada uma revisão sobre sensores de temperatura e pressão utilizando fibras convencionais, redes de Bragg e fibras de cristal fotônico. Finalmente são mostrados e discutidos os resultados dos experimentos com pressão em uma fibra de cristal fotônico de núcleo oco, para a qual foram identificados, caracterizados e reportados pela primeira vez bandgaps de ordem superior localizados na região visível do espectro, que são sensíveis à pressão. Aplicando-se pressão hidrostática na parte externa da fibra obteve-se variação de alguns dB na transmissão óptica para pressões de centenas de kgf/cm², enquanto que quando a pressão era aplicada no interior dos buracos da fibra obteve-se variação semelhante para unidades de kgf/cm². Também foi analisada a resposta da polarização da luz guiada, e portanto da birrefringência da fibra, à pressão interna. Em outra parte do trabalho experimental foi caracterizada a resposta à temperatura do deslocamento espectral dos bandgaps em fibras de bandgap fotônico. Foram caracterizadas as respostas de uma fibra de núcleo oco, uma fibra híbrida e uma fibra totalmente sólida com deslocamentos de até 36 pm/°C para fibras esticadas. Para a fibra totalmente sólida foi também caracterizada a influência da curvatura da fibra sobre os bandgaps e como o deslocamento devido à temperatura é afetado nessas condições. Para uma fibra esticada é apresentado um modelo para o cálculo aproximado do deslocamento dos bandgaps em função da temperatura obtendo-se resultados satisfatórios com o experimento. Na ultima parte do trabalho são apresentadas as conclusões finais.
27

Vestavěný systém pro automatizaci chovné stanice akvarijních ryb / Embedded System for Automation of Aquarium Fish Breeding Station

Moc, Filip January 2018 (has links)
This master's thesis is concerned about embedded system for automatic water renewal in aquariums. Besides water renewal system also controls lights and ventilation in aquarium fish breeding station. In this report you will find informtions about technology relevant to automation of aquarium fish breeding station. Also you will find here informations about design and implementation of my specific final working solution.
28

Meteorologická stanice se vzdáleným přístupem / Meteorological Station with Remote Access

Svoboda, Josef January 2010 (has links)
This thesis discusses design and realization of air temperature, pressure and relative humidity measuring device, transmission of measured data over internet and their presentation on a web site. First chapter introduces reader into principles of measuring air temperature, pressure and relative humidity and various types of sensors used for measuring . Next, the conception of designed system is described. Designed system must accomplish tasks from reading raw data from the sensor up to thein graphical presentation to the internet user. Second and third chapter describes hardware and software design of air temperature, pressure and relative humidity measuring unit. In next part one can find description of software used to transmit measured data over internet and software for generating web pages which are shown to users. The work is revieved in the final part of this thesis.
29

Representing Data Quality for Streaming and Static Data

Lehner, Wolfgang, Klein, Anja, Do, Hong-Hai, Hackenbroich, Gregor, Karnstedt, Marcel 19 May 2022 (has links)
In smart item environments, multitude of sensors are applied to capture data about product conditions and usage to guide business decisions as well as production automation processes. A big issue in this application area is posed by the restricted quality of sensor data due to limited sensor precision as well as sensor failures and malfunctions. Decisions derived on incorrect or misleading sensor data are likely to be faulty. The issue of how to efficiently provide applications with information about data quality (DQ) is still an open research problem. In this paper, we present a flexible model for the efficient transfer and management of data quality for streaming as well as static data. We propose a data stream metamodel to allow for the propagation of data quality from the sensors up to the respective business application without a significant overhead of data. Furthermore, we present the extension of the traditional RDBMS metamodel to permit the persistent storage of data quality information in a relational database. Finally, we demonstrate a data quality metadata mapping to close the gap between the streaming environment and the target database. Our solution maintains a flexible number of DQ dimensions and supports applications directly consuming streaming data or processing data filed in a persistent database.
30

Machine Learning of Heater Zone Sensors in Liquid Sodium Facility

Maria Pantopoulou (16494174) 06 July 2023 (has links)
<p>  </p> <p>Advanced high temperature fluid reactors (AR), such as sodium fast reactors (SFR) and molten salt cooled reactors (MSCR) are promising nuclear energy options, which offer lower levelized electricity costs compared to existing light water reactors (LWR). Increasing economic competitiveness of ARs in the open market involves developing strategies for reducing operation and maintenance (O&M) costs. Digitization of AR’s allows to implement continuous on-line monitoring paradigm to achieve early detection of incipient problems, and thus reduce O&M costs. Machine learning (ML) algorithms offer a number of advantages for reactor monitoring through anticipation of key performance variables using data-driven process models. ML model does not require detailed knowledge of the system, which could be difficult to obtain or unavailable because of commercial privacy restrictions. In addition, any data obtained from sensors or through various ML models need to be securely transmitted under all possible conditions, including those of cyber-attacks. Quantum information processing offers promising solutions to these threats by establishing secure communications, due to unique properties of entanglement and superposition in quantum physics. More specifically, quantum key distribution (QKD) algorithms can be used to generate and transmit keys between the reactor and a remote user. In one of popular QKD communication protocols, BB84, the symmetric keys are paired with an advanced encryption standard (AES) protocol protecting the information. Another challenge in sensor measurements is the noise, which can affect the accuracy and reliability of the measured values. The presence of noise in sensor measurements can lead to incorrect interpretations of the data, and therefore, it is crucial to develop effective signal processing techniques to improve the quality of measurements. </p> <p>In this study, we develop several variations of Recurrent Neural Networks (RNN) and test their ability to predict future values of thermocouple measurements. Data obtained by a heat-up experiment conducted in a liquid sodium experimental facility is used for training and testing the RNNs. The method of extrapolation is also explored using measurements of different sensors to train and test a network. We then examine through computer simulations the potential of secure real-time communication of monitoring information using the BB84 protocol. Finally, signal analysis is performed with Discrete Fourier Transform (DFT) sensor signals to analyze and correlate the prediction results with the results obtained by the analysis of the time series in the frequency domain. Using information from the frequency analysis, we apply cutoff filters in the original time series and test again the performance of the networks. Results show that the ML models developed in this work can be efficiently used for forecasting of thermocouple measurements, as they provide Root Mean Square Error (RMSE) values lower than the measurement uncertainty of the thermocouples. Extrapolation produces good results, with performance related to the Euclidean distance between the sets of time series. Moreover, the results from the utilization of the BB84 protocol to securely transmit the measurements prove the feasibility of secure real-time communication of monitoring information. The application of the cutoff filters provided more accurate predictions of the thermocouple measurements than in the case of the unfiltered signals.</p> <p>The suit of computational tools developed in this work is shown to be efficient and promises to have a positive impact on improving performance of an AR.</p>

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