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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.
1

Mensuração direta do pH do solo em campo por meio de eletrodos íon-seletivos / On-the-go soil sensing for pH determination using ion-selective electrodes

Silva, Fernanda Cristina de Souza 18 November 2013 (has links)
Um dos fatores mais limitantes da produtividade das culturas não somente no Brasil, mas em várias partes do mundo é a acidez do solo. Buscando-se a detecção automática da variação de elementos químicos do solo, além de velocidade e economia nas amostragens e análises, diversas técnicas de sensoriamento de solo têm sido estudadas. O presente trabalho estudou o desempenho de um conjunto sensor de íon seletivo de antimônio, para seus dois modos de funcionamento disponíveis, denominados de automático e manual, na determinação do potencial hidrogeniônico (pH) em tempo real em três áreas com solos de diferentes características físicas e químicas, as quais passaram por amostragem de solo em grade, com densidade de 4 amostras ha-1, tendo sido encaminhados a laboratório para a determinação do pH em água e cloreto de cálcio, os quais foram utilizados como referência. Sem intervenção do operador, seguindo-se configurações do fabricante, amostras foram coletadas em campo automaticamente. As amostras determinadas sob acionamento manual foram utilizadas para avaliações dos parâmetros de desempenho do conjunto, definidos como tempo, precisão e acurácia, por meio do cálculo da raiz quadrada do erro médio (RMSE). Um conjunto de amostras de solo foi utilizado na avaliação do grau de influência da umidade na determinação do pH. Diferentes retas de calibração utilizando os dados mensurados via sensoriamento e os valores obtidos em laboratório foram construídas, sendo uma delas elaborada especificamente por área e a outra abrangendo a totalidade de pontos numa reta universal. Por meio de análises geoestatísticas buscou-se definir e comparar a estrutura de dependência espacial dos dados com a construção de semivariogramas e ajuste do modelo para a variável em estudo. Os dados brutos coletados pelo sensor e os calibrados, juntamente àqueles com origem em laboratório foram utilizados na construção de mapas de superfície. Pontos de validação foram tomados para avaliar a qualidade das retas de calibração. As análises estatísticas apresentaram melhor resultado para o modo manual, porém, para ambos os modos de funcionamento foram verificados erros superiores aos determinados como limite, uma vez que as curvas de calibração não foram eficientes. O conjunto apresentou sensibilidade ao íon H+ para ambos os modos de acionamento, porém, verificou-se que a umidade do solo interferiu no resultado das leituras. Os parâmetros geoestatísticos mostraram que as amostragens atuais não exploram integralmente a variabilidade do pH das áreas, confirmando o potencial do sensoriamento em tempo real e a necessidade de aprimoramento dessas técnicas. Como primeiro passo sugere-se o acréscimo de um sensor de umidade ao conjunto e a utilização de ferramentas para padronização e homogeneização das amostras em campo. / One of the most limiting factors in crop not only in Brazil but in many parts of the world is soil acidity. Aiming to automatic detection of changes in soil chemical elements, as well as speed and economy in the sampling and analysis, various sensing techniques of soil have been studied. The present work studied the performance of a set of sensor selective ion antimony to its two available operating modes, automatic and manual called, in determining the hydrogen potential (pH) in real time on three areas with different soil physical characteristics and chemical, which passed soil sampling grid at a density of 4 samples ha-1 and was sent to the laboratory for the determination of the pH and calcium chloride, which were used as reference. Without operator intervention, following the manufacturer settings, samples were collected in the field automatically. The samples under certain manual actuation were used for evaluation of the performance parameters of the set, defined as time precision and accuracy by calculating the root mean square error (RMSE). A set of soil samples was used to assess the degree of influence of moisture in the pH determining. Different straight calibration using the measured data via sensing and the values obtained in the laboratory were built, one being designed specifically for the area and the other covering the whole of points on a straight universal. Through geostatistical analyzes sought to define and compare the spatial dependence structure of the data with the construction of semi-variograms and model fit for the variable under study. The raw data collected by the sensor and the calibrated along with those originated in the laboratory were used to make surface maps. Validation points were taken to assess the quality of the calibration straight. Statistical analysis showed better results for the manual mode, however, for both operation modes were checked for errors upper limit as determined, since calibration curves are not effective. The set had a sensitivity to the H+ ion for both activation modes, however, it was found that soil moisture affected the outcome of the readings. The geostatistical parameters showed that the samples do not exploit fully the current pH variability areas, confirming the potential of real-time sensing and the need for improvement of these techniques. Initially we suggest the addition of a humidity sensor and use of tools for standardization and homogenization of samples in the field.
2

Real-time Interrogation of Fiber Bragg Grating Sensors Based on Chirped Pulse Compression

Liu, Weilin 05 October 2011 (has links)
Theoretical and experimental studies of real-time interrogation of fiber Bragg grating (FBG) sensors based on chirped pulse compression with increased interrogation resolution and signal-to-noise ratio are presented. Two interrogation systems are proposed in this thesis. In the first interrogation system, a linearly chirped FBG (LCFBG) is employed as the sensing element. By incorporating the LCFBG in an optical interferometer as the sensor encoding system, employing wavelength-to-time mapping and chirped pulse compression technique, the correlation of output microwave waveform with a chirped reference waveform would provide an interrogation result with high speed and high resolution. The proposed system can provide an interrogation resolution as high as 0.25 μ at a speed of 48.6 MHz. The second interrogation system is designed to achieve simultaneous measurement of strain and temperature. In this system, a high-birefringence LCFBG (Hi-Bi LCFBG) is employed as a sensing element.
3

Real-time Interrogation of Fiber Bragg Grating Sensors Based on Chirped Pulse Compression

Liu, Weilin 05 October 2011 (has links)
Theoretical and experimental studies of real-time interrogation of fiber Bragg grating (FBG) sensors based on chirped pulse compression with increased interrogation resolution and signal-to-noise ratio are presented. Two interrogation systems are proposed in this thesis. In the first interrogation system, a linearly chirped FBG (LCFBG) is employed as the sensing element. By incorporating the LCFBG in an optical interferometer as the sensor encoding system, employing wavelength-to-time mapping and chirped pulse compression technique, the correlation of output microwave waveform with a chirped reference waveform would provide an interrogation result with high speed and high resolution. The proposed system can provide an interrogation resolution as high as 0.25 μ at a speed of 48.6 MHz. The second interrogation system is designed to achieve simultaneous measurement of strain and temperature. In this system, a high-birefringence LCFBG (Hi-Bi LCFBG) is employed as a sensing element.
4

Real-time Interrogation of Fiber Bragg Grating Sensors Based on Chirped Pulse Compression

Liu, Weilin 05 October 2011 (has links)
Theoretical and experimental studies of real-time interrogation of fiber Bragg grating (FBG) sensors based on chirped pulse compression with increased interrogation resolution and signal-to-noise ratio are presented. Two interrogation systems are proposed in this thesis. In the first interrogation system, a linearly chirped FBG (LCFBG) is employed as the sensing element. By incorporating the LCFBG in an optical interferometer as the sensor encoding system, employing wavelength-to-time mapping and chirped pulse compression technique, the correlation of output microwave waveform with a chirped reference waveform would provide an interrogation result with high speed and high resolution. The proposed system can provide an interrogation resolution as high as 0.25 μ at a speed of 48.6 MHz. The second interrogation system is designed to achieve simultaneous measurement of strain and temperature. In this system, a high-birefringence LCFBG (Hi-Bi LCFBG) is employed as a sensing element.
5

Mensuração direta do pH do solo em campo por meio de eletrodos íon-seletivos / On-the-go soil sensing for pH determination using ion-selective electrodes

Fernanda Cristina de Souza Silva 18 November 2013 (has links)
Um dos fatores mais limitantes da produtividade das culturas não somente no Brasil, mas em várias partes do mundo é a acidez do solo. Buscando-se a detecção automática da variação de elementos químicos do solo, além de velocidade e economia nas amostragens e análises, diversas técnicas de sensoriamento de solo têm sido estudadas. O presente trabalho estudou o desempenho de um conjunto sensor de íon seletivo de antimônio, para seus dois modos de funcionamento disponíveis, denominados de automático e manual, na determinação do potencial hidrogeniônico (pH) em tempo real em três áreas com solos de diferentes características físicas e químicas, as quais passaram por amostragem de solo em grade, com densidade de 4 amostras ha-1, tendo sido encaminhados a laboratório para a determinação do pH em água e cloreto de cálcio, os quais foram utilizados como referência. Sem intervenção do operador, seguindo-se configurações do fabricante, amostras foram coletadas em campo automaticamente. As amostras determinadas sob acionamento manual foram utilizadas para avaliações dos parâmetros de desempenho do conjunto, definidos como tempo, precisão e acurácia, por meio do cálculo da raiz quadrada do erro médio (RMSE). Um conjunto de amostras de solo foi utilizado na avaliação do grau de influência da umidade na determinação do pH. Diferentes retas de calibração utilizando os dados mensurados via sensoriamento e os valores obtidos em laboratório foram construídas, sendo uma delas elaborada especificamente por área e a outra abrangendo a totalidade de pontos numa reta universal. Por meio de análises geoestatísticas buscou-se definir e comparar a estrutura de dependência espacial dos dados com a construção de semivariogramas e ajuste do modelo para a variável em estudo. Os dados brutos coletados pelo sensor e os calibrados, juntamente àqueles com origem em laboratório foram utilizados na construção de mapas de superfície. Pontos de validação foram tomados para avaliar a qualidade das retas de calibração. As análises estatísticas apresentaram melhor resultado para o modo manual, porém, para ambos os modos de funcionamento foram verificados erros superiores aos determinados como limite, uma vez que as curvas de calibração não foram eficientes. O conjunto apresentou sensibilidade ao íon H+ para ambos os modos de acionamento, porém, verificou-se que a umidade do solo interferiu no resultado das leituras. Os parâmetros geoestatísticos mostraram que as amostragens atuais não exploram integralmente a variabilidade do pH das áreas, confirmando o potencial do sensoriamento em tempo real e a necessidade de aprimoramento dessas técnicas. Como primeiro passo sugere-se o acréscimo de um sensor de umidade ao conjunto e a utilização de ferramentas para padronização e homogeneização das amostras em campo. / One of the most limiting factors in crop not only in Brazil but in many parts of the world is soil acidity. Aiming to automatic detection of changes in soil chemical elements, as well as speed and economy in the sampling and analysis, various sensing techniques of soil have been studied. The present work studied the performance of a set of sensor selective ion antimony to its two available operating modes, automatic and manual called, in determining the hydrogen potential (pH) in real time on three areas with different soil physical characteristics and chemical, which passed soil sampling grid at a density of 4 samples ha-1 and was sent to the laboratory for the determination of the pH and calcium chloride, which were used as reference. Without operator intervention, following the manufacturer settings, samples were collected in the field automatically. The samples under certain manual actuation were used for evaluation of the performance parameters of the set, defined as time precision and accuracy by calculating the root mean square error (RMSE). A set of soil samples was used to assess the degree of influence of moisture in the pH determining. Different straight calibration using the measured data via sensing and the values obtained in the laboratory were built, one being designed specifically for the area and the other covering the whole of points on a straight universal. Through geostatistical analyzes sought to define and compare the spatial dependence structure of the data with the construction of semi-variograms and model fit for the variable under study. The raw data collected by the sensor and the calibrated along with those originated in the laboratory were used to make surface maps. Validation points were taken to assess the quality of the calibration straight. Statistical analysis showed better results for the manual mode, however, for both operation modes were checked for errors upper limit as determined, since calibration curves are not effective. The set had a sensitivity to the H+ ion for both activation modes, however, it was found that soil moisture affected the outcome of the readings. The geostatistical parameters showed that the samples do not exploit fully the current pH variability areas, confirming the potential of real-time sensing and the need for improvement of these techniques. Initially we suggest the addition of a humidity sensor and use of tools for standardization and homogenization of samples in the field.
6

Real-time Interrogation of Fiber Bragg Grating Sensors Based on Chirped Pulse Compression

Liu, Weilin January 2011 (has links)
Theoretical and experimental studies of real-time interrogation of fiber Bragg grating (FBG) sensors based on chirped pulse compression with increased interrogation resolution and signal-to-noise ratio are presented. Two interrogation systems are proposed in this thesis. In the first interrogation system, a linearly chirped FBG (LCFBG) is employed as the sensing element. By incorporating the LCFBG in an optical interferometer as the sensor encoding system, employing wavelength-to-time mapping and chirped pulse compression technique, the correlation of output microwave waveform with a chirped reference waveform would provide an interrogation result with high speed and high resolution. The proposed system can provide an interrogation resolution as high as 0.25 μ at a speed of 48.6 MHz. The second interrogation system is designed to achieve simultaneous measurement of strain and temperature. In this system, a high-birefringence LCFBG (Hi-Bi LCFBG) is employed as a sensing element.
7

Canadian homeless mobilities: relational perspectives on At Home/Chez Soi participants’ interurban migrations

Kaufman, Andrew 29 August 2016 (has links)
This thesis examines the mobility patterns of 613 participants from the At Home/Chez Soi Research Demonstration Project on Mental Health and Homelessness who were surveyed in five Canadian cities (Vancouver, Winnipeg, Toronto, Montréal, and Moncton). Participants’ mobility histories are treated as life courses: visualized using a GIS spatiotemporal analysis and complemented by examining their self-described reasons for movement (n=1,750). I contend that homeless mobilities are complex, entangled, and multiple. To better understand these mobilities, I apply relational theoretical perspectives to literature from the mobilities turn. I conceptualize mobility as composed of the relations between various actors. These relations coordinate amidst social differences, histories, and orderings of power. Together, actors and the relations between them, become more than the sum of their parts. To see mobility relationally, is to say that mobilities have emergent properties that reproduce, deepen, or ameliorate marginalization for those experiencing homelessness. I identify a series of actors and their relations composing homeless mobilities via time-space mapping, descriptive statistics, and the exploratory coding of survey data. I conclude by detailing a relational view of homeless mobilities while suggesting that expulsion is one emergent property of this system. / October 2016
8

Interaktive Stadtkarten als Instrumente der Erkenntnis

Bedö, Viktor 14 November 2011 (has links)
Dieser Dissertation liegt die Problematik des impliziten verkörperten Wissens im Erkennen und Entdecken mittels visueller Instrumente zu Grunde. Mit Entdeckung ist der Akt des allerersten Erkennens von etwas gemeint, über dessen Existenz oder Beschaffenheit dem Entdecker zuvor keine expliziten Kenntnisse zur Verfügung standen. Eine zentrale These dieser Arbeit besagt, dass dies durch den transmodalen Charakter der empirischen Begriffsbildung gesichert wird. Dieses erkenntnistheoretische Problem wird anhand des Entdeckens von emergenten Mustern urbaner Organisation ausgearbeitet, die aus der Vogelperspektive auf urbanen Echtzeitkarten erscheinen. In der Arbeit werden Trends interaktiver Kartierung aufgezeigt, bei denen unter anderem urbane Sensordaten, Daten aus der Verortung von Personen, Objekten und Information und anwendergenerierte Informationen visualisiert werden. Die Konklusion beinhaltet Ausblicke, an welchen Punkten die anhand der interaktiven Karten gewonnenen Erkenntnisse in Stadtentwicklungsprojekte und in die Entwicklung von ortssensitiven Technologien einfließen können. / This dissertation elaborates on the role of implicit embodied knowledge in recognition and discovery through the use of visual instruments. Discovery refers to the very first act of recognition of something, that''s existence or features were not explicitly known by the discovering person beforehand. According to a central thesis of this work discovery is enabled by the transmodal character of empirical concept formation. This epistemological question is elaborated based on the case of emergent patterns of urban organization that appear on urban real-time maps from the bird''s eye view. Trends of interactive mapping are shown where urban sensor-data, location data of persons, objects, and information, as well as user generated information is visualized. The conclusion contains outlooks how knowledge gained from interactive urban maps can be utilized in urban development projects and in the development of location sensitive technologies.
9

Sänka bundet kapital i ett mellanlager : -En studie utförd i syfte att finna orsaken till varför lager bildas för att därefter presentera en eller flera åtgärder som bidrar till minskat bundet kapital i lager / Decrease tied up capital in stock : -A case study conducted in purpose to find root causes to how stocks is formed and thereafter introduce one or many arrangements with intention to reduce tied up kapital in stock

Svensson, Gustav, Nilsson, Jesper January 2018 (has links)
Purpose – Globalization affects all producing companies with increased complexity in production, stock management and never ending customer demands. The customers of today have a greater range of suppliers than before with even more products to choose from which puts the customer in a strong position. One of many important subjects that companies need to work with to keep their competitiveness strong against each other is to work with continuous improvements in production- and inventory management. This study therefore reviews tied up capital in stock and suggest adequate procedures, which could be applied to decrease the tied up capital.   Method –In order to fulfil the purpose a case study is conducted. Two central research questions are chosen for the study to investigate in a case company. The data collected contains of secondary data, observations and interviews. To accomplish the purpose a theoretical framework has been put together.   Findings – Reducing variations in production and re-designing of the daily production plan is presented as the two procedures with the purpose to achieve a decrease in tied up capital for stock kept units. The study describes these two procedures in general in order to make the solution applicable into various manufacturing company. Further the study claims that gaining flow efficiency should be prioritized instead of resource efficiency, which could be accomplished by the two procedures.    Implications – The study contributes to verifying production theories, foremost about variations in production, Lean manufacturing and the technique of Lead-time mapping.   Limitations – In order to apply the procedures with precision and efficiency some further data and extended studies needs to be performed. This study is performed in a generalizing point of view, which may influence the results.  The study does not capture every aspect of affecting circumstances that might be needed for a successful implementation of suggested procedures.   Keywords – Tied up capital, Lead-time, Lean, Lead-time mapping, Variations, Flow efficiency, Postponement, Just-in-Time, Make-to-stock and Make-to-order. / Syfte – Globaliseringen har gjort att kunden har ett högre utbud att välja mellan och kan därmed ställa högre krav på tillverkande verksamheter. För att fortsatt vara konkurrenskraftig måste verksamheter ständigt utveckla den interna produktion- och materialstyrningen. Studiens ämnar därmed undersöka orsaken till uppkomsten av bundet kapital i lager samt finna potentiella åtgärder som kan vidtas inom verksamheten för att på ett hållbart sätt minska bundet kapital i lager.   Metod – För att uppfylla studiens syfte tillämpas fallstudie. Studien utgår från två frågeställningar som besvaras med hjälp av data från ett fallföretag. Data som samlas är hämtad från sekundärdata, observationer och intervjuer. Därtill har ett teoretiskt ramverk upprättats vilken studien utgår ifrån.   Resultat – Minska variationer samt utförande av en mer detaljerad planering presenteras som studiens två åtgärdsförslag för att minska bundet kapital i lager. Studien beskriver övergripande potentiella tillvägagångssätt för att åstadkomma förslagen. Studien konstaterar att flödeseffektivitet med fördel bör prioriteras framför resurseffektiviteten i verksamheten, vilket uppfylls med hjälp av åtgärdsförslagen.   Implikationer – Studien bidrar inte till nya teorier men verifierar befintliga teorier främst kring variationer i tillverkning, Lean och ledtidskartläggning.   Begränsningar – För att åtgärdsförslagen i studiens resultat ska kunna tillämpas krävs ytterligare data och fördjupade studier för att garantera att samtliga aspekter ska fångas in samt att orsak och påverkan av åtgärderna ska kunna kartläggas. Studien bygger på generaliserande antaganden vilket ger ett generaliserat resultat.   Nyckelord – Lean, Ledtid, Ledtidskartläggning, Variationer, Flödeseffektivitet, Senareläggning, Just-in-Time, Make-to-order och Bundet kapital.

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