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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.
161

How remote work affect employee productivity

Gegerfelt, Jakob, Sandström, Moa January 2023 (has links)
Due to the covid-19 pandemic, the world of remote work exploded. This study investigates how remote work affect employee productivity. The data is collected through a web-based questionnaire where Swedish employees and managers respond to questions related to remote work productivity. There are some previous studies of the topic, based on data from other countries. However, studies covering the Swedish market are limited, whereas this thesis contributes to that knowledge gap. The study includes the independent variables desire to work remotely, age, family situation, gender, educational background, collaboration, and support from management, to recognize what factors have an impact on employee productivity as dependent variable. The results indicate that both employees and managers recognize an average increase in employee productivity, where the factors desire to work remote, age and family situation are found to have a significant impact on productivity. Furthermore, the study also found that the vast majority of workers prefer a hybrid work solution where 40-60% is conducted remotely to utilize the benefits of both options.
162

Даљинско управљање дигиталном пнеуматиком у концепту Индустрије 4.0 / Daljinsko upravljanje digitalnom pneumatikom u konceptu Industrije 4.0 / Remote control of the digital pneumatics in a scope of Industry 4.0

Reljić Vule 28 August 2020 (has links)
<p>У овој докторској дисертацији, акценат је стављен на анализу даљински<br />управљаних дигиталних пнеуматских система у концепту Индустрије 4.0.<br />Доприноси тезе су сљедећи: 1) Показано је на који начин је могуће, постојеће<br />пнеуматске системе надградити тако да се омогући даљинско управљање<br />кретањем пнеуматских радних елемената, даљинска регулација притиска и<br />даљинска регулација протока. 2) Показано је на који начин је могуће развити<br />даљински управљан дигитални пнеуматски систем, који има могућност<br />даљинске промјене управљачких параметара (радног притиска и/или<br />протока) у току процеса рада, и који је искључиво софтверски<br />реконфигурабилан, те реализован на оптималан начин, чиме достиже ниво<br />флексибилности потребан да се задовољи основни концепт Индустрије 4.0.<br />Примјена добијених резултата могућа је у свим индустријским, а потом и<br />неиндустријским системима, у којима постоје пнеуматски радни елементи.</p> / <p>U ovoj doktorskoj disertaciji, akcenat je stavljen na analizu daljinski<br />upravljanih digitalnih pneumatskih sistema u konceptu Industrije 4.0.<br />Doprinosi teze su sljedeći: 1) Pokazano je na koji način je moguće, postojeće<br />pneumatske sisteme nadgraditi tako da se omogući daljinsko upravljanje<br />kretanjem pneumatskih radnih elemenata, daljinska regulacija pritiska i<br />daljinska regulacija protoka. 2) Pokazano je na koji način je moguće razviti<br />daljinski upravljan digitalni pneumatski sistem, koji ima mogućnost<br />daljinske promjene upravljačkih parametara (radnog pritiska i/ili<br />protoka) u toku procesa rada, i koji je isključivo softverski<br />rekonfigurabilan, te realizovan na optimalan način, čime dostiže nivo<br />fleksibilnosti potreban da se zadovolji osnovni koncept Industrije 4.0.<br />Primjena dobijenih rezultata moguća je u svim industrijskim, a potom i<br />neindustrijskim sistemima, u kojima postoje pneumatski radni elementi.</p> / <p>In this PhD thesis, the emphasis is placed on the analysis of remotely<br />controlled digital pneumatic systems in the scope of Industry 4.0. The<br />contributions of the thesis are the following: 1) The possibility of upgrading an<br />existing pneumatic systems to allow remote motion control of pneumatic<br />actuators, remote pressure control and remote flow control, is shown. 2) The<br />possibility of developing a remotely controlled digital pneumatic system, which<br />has the ability of remote change of the control parameters (the operating<br />pressure and/or the flow) during the operating process, and which is<br />exclusively software reconfigurable and optimally implemented, is shown. At<br />that way, it is achieving a level of flexibility needed to meet the basic concept<br />of Industry 4.0. The application of the obtained results is possible in all<br />industrial and then non-industrial systems, where pneumatic actuators exist.</p>
163

Tactical decision aid for unmanned vehicles in maritime missions

Duhan, Daniel P. 03 1900 (has links)
Approved for public release; distribution is unlimited / An increasing number of unmanned vehicles (UV) are being incorporated into maritime operations as organic elements of Expeditionary and Carrier Strike Groups for development of the recognized maritime picture. This thesis develops an analytically-based planning aid for allocating UVs to missions. Inputs include the inventory of UVs, sensors, their performance parameters, and operational scenarios. Operations are broken into mission critical functions: detection, identification, and collection. The model output assigns aggregated packages of UVs and sensors to one of the three functions within named areas of interest. A spreadsheet model uses conservative time-speed-distance calculations, and simplified mathematical models from search theory and queuing theory, to calculate measures of performance for possible assignments of UVs to missions. The spreadsheet model generates a matrix as input to a linear integer program assignment model which finds the best assignment of UVs to missions based on the user inputs and simplified models. The results provide the mission planner with quantitatively-based recommendations for unmanned vehicle mission tasking in challenging scenarios. / Lieutenant, United States Navy
164

Développement d'un capteur magnéto acoustique on-chip pour la caractérisation des matériaux complexes / Magneto-acoustic on-chip sensor design for the characterization of complex materials

Wang, Yu 13 October 2014 (has links)
Les ondes acoustiques et électromagnétiques offrent des méthodes de caractérisation des matériaux très peu invasives. Souvent utilisées à l'aide de capteurs indépendants, l'approche développée ici est de proposer un résonateur multimodal acoustique et électromagnétique. Afin de répondre à une grande variété d'applications, le choix de l'élément actif piézo-électrique s'est porté sur un disque de quartz de coupe AT. L'étude s'articule autour des étapes aboutissant in fine à un capteur magnéto acoustique on-chip à excitation sans contact.L'étude théorique d'un capteur magnéto-acoustique à excitation inductive est tout d'abord réalisée pour un capteur chargé par un fluide visqueux. Ce capteur est constitué de trois éléments : une sonde radiofréquence (RF), un résonateur RF à fort facteur de qualité et le quartz sur lequel ont été déposées deux électrodes en anneau. Cette étude montre comment déduire la viscosité complexe du matériau étudié à partir de l'impédance électrique du système complet. Les mesures effectuées sur des mélanges étalons montrent une très bonne correspondance avec les résultats théoriques.L'intégration du résonateur RF sur l'élément piézo-électrique s'effectuant via des électrodes circulaires, une étude préliminaire est menée sur les ondes acoustiques pouvant être générées sur le quartz et leur interaction avec les électrodes. Les mesures de vibration par vibrométrie laser montrent que des ondes de Lamb sont générées dans une large gamme de fréquence (de 100 kHz à 20 MHz). L'analyse de la réponse impulsionnelle spatiale par transformée de Gabor 3D localise la source de ces ondes sur le bord des électrodes. Par ailleurs, l'étude du disque au fondamental montre une grande non-linéarité mécanique du quartz.Le modèle de résonateur RF plan multi-tour puis son intégration sur le disque de quartz du capteur magnéto-acoustique on-chip sont ensuite étudiés. Les résultats expérimentaux par mesure d'impédance et vibrométrie laser valident le modèle. La gamme de fréquence sélectionnée (entre 5 et 20 MHz) permet d'envisager des mesures micro-rhéologiques. / Acoustic and electromagnetic waves are key probing candidates for characterizing their propagation media with minimum perturbation. Often used with independent sensors based on specialized transducing materials, the approach developed here provides an on-ship multimodal sensor using the same sensing material for probing the acoustic and electromagnetic properties of the material. To meet a wide range of applications, the choice of the active piezoelectric element is carried out on an AT cut quartz. The study focuses on the steps leading in fine to an on-chip magneto-acoustic sensor with a contactless excitation.The theoretical study of a magneto-acoustic sensor inductively excited and loaded by a viscous fluid is first carried out. This sensor consists of three elements: a radio frequency (RF) sensor, a high quality factor RF resonator and a quartz on which two ring electrodes have been deposited. The complex viscosity of the studied material is derived from the electrical impedance of the complete system. The measurements carried on etalon viscoelastic materials show a good agreement with the theoretical results.The integration of the RF resonator on the piezoelectric element being via circular electrodes, a preliminary study is performed for determining the acoustic waves that can be generated in the quartz and their interaction with the electrodes. The laser vibrometry measurements indicate that Lamb waves are generated in a wide frequency range, from 100 kHz to 20 MHz. The analysis of the spatial pulse response of the sensor surface by 3D Gabor transform locates the source of these waves on the edge of the electrodes. Furthermore, the study of the disk at it fundamental frequency points out the high nonlinear mechanical behavior of the quartz.The plane RF multi-turn resonator and its integration on the quartz disk of the magneto-acoustic on-chip sensor are then studied. The experimental results of impedance and laser vibrometry measurements validate the proposed theoretical model. The selected frequency range (between 5 and 20 MHz) allows one to consider micro rheological measurements.
165

Restabelecimento de energia por reconfiguração de redes em sistemas de distribuição de grande porte com priorização de chaves, consumidores e definição de sequência de chaveamento / Service restoration by network reconfiguration in large scale distribution systems with switches and consumers priorization and switching sequence definition

Marques, Leandro Tolomeu 29 August 2013 (has links)
Na ocorrência de uma ou de múltiplas faltas permanentes em sistemas de distribuição de energia elétrica é inevitável a ausência de fornecimento à algumas cargas. Contudo, devido à presença de chaves seccionadoras, após a localização e isolação do trecho sob falta, é possível restaurar o abastecimento de energia a estas cargas fora de serviço. Para tal é necessária a obtenção de um plano de restabelecimento adequado, no menor intervalo de tempo possível, capaz de informar as chaves que devem ser operadas a fim de reconectar estas cargas à rede e sem sobrecarregar nenhum equipamento. Neste sentido, têm sido propostas metodologias para auxiliar as atividades dos operadores de sistemas de distribuição por meio do fornecimento de planos de restabelecimento de energia em situações de contingência. Todavia, a aplicação da maioria destas técnicas restringe-se à redes pequenas, quando comparadas às redes reais que possuem milhares de barras e chaves. Em outras metodologias, na tentativa de superar esta limitação, são feitas simplificações na representação da rede, desconsiderando alguns dos seus elementos. Nestes casos, a solução fornecida para a rede simplificada pode não ter o mesmo desempenho na rede em operação, o que compromete a confiabilidade dessas metodologias. Em outros métodos, ainda, a rede é representada com todas as suas barras e chaves, no entanto, deixam de considerar a presença de consumidores especiais, que exigem prioridade de fornecimento, bem como de chaves existentes na rede que podem ser operadas remotamente. Face ao exposto, propõe-se uma metodologia para determinação, em tempo real, de planos de restabelecimento de energia elétrica em sistemas de distribuição de grande porte em situações de uma ou de múltiplas faltas. Para lidar com os múltiplos objetivos deste problema, sendo alguns dele conflitantes entre si, esta será baseada em Algoritmos Evolutivos Multi-Objetivo, enquanto que a representação computacional sem simplificações da rede será proporcionada por uma codificação de dados apoiada na teoria de grafos e denominada Representação Nó-Profundidade. A fim de diminuir o tempo e o custo de implementação dos planos obtidos, será considerada e dado prioridade de manobra às chaves controladas remotamente, que podem ser alteradas do centro de operações. Será dado prioridade também ao fornecimento de energia de consumidores especiais. Por fim, para cada plano de restabelecimento fornecido será definida uma sequência factível de chaves que, quando alteradas, reconectarão as cargas sãs fora de serviço e eliminarão sobrecargas ou perfis de tensão inadequados. Para validar a metodologia proposta serão realizadas simulações computacionais no sistema de distribuição real da cidade de São Carlos-SP, em operação no ano de 1994, e nas suas versões duplicada, quadruplicada e octuplicada. / The occurrence of one or multiple permanent faults in electric power distribution systems is inevitable the privation of the service to some loads. However, due to the presence of switches, after the location and isolation of the faulted section, you can restore the power supply to these out of service loads. To this it is necessary to obtain, as soon as possible, a suitable restoration plan. It must be able to inform the switches that must be operated in order to reconnect these loads without overloading on any network or equipment. In this sense, it has been proposed methods to assist the operators\' activities of the of distribution systems by providing plans to restore the service in contingency situations. However, the application of the most of these techniques is limited to small networks, when they are compared to real networks that have thousands of bars and keys. In other methodologies, in order to overcome this limitation, simplications are made in the representation of the network, ignoring some of its elements. In these cases, the solution provided for a simplied network may not have the same performance on the network in operation, which aects the reliability of these methodologies. In other methods, the network is represented with all of its bars and switches. However, these methodologies do not consider the presence of the special consumers that require service priority neither the switches that can be operated remotely. Given the above, we propose a methodology for determining, in real time, plans for service restoration in large-scale electric distribution systems in situations of one or multiple faults. To deal with the multiple objectives of this problem, some of them con icting, the proposed method will be based on Multi-Objective Evolutionary Algorithms. Moreover, the computational representation without simplications of the network will be provided by a data encoding based in graph theory and called Node-Depth Encoding. In order to reduce the time and cost of the implementation of the plans obtained, it will be considered and given priority to maneuvers in remotely controlled switches, which can be changed from the operation center. Priority will be given also to the power supply of special consumers. Finally, for each restoration plan provided will be gotten a feasible switching sequence that, when implemented, will reconnect the out of service loads and eliminate overloads or inadequate voltage proles. To validate the proposed methodology it will be performed computer simulations in the real distribution system of the São Carlos-SP city, in operation in 1994, and their doubled, quadruplicate and octuplicate versions.
166

MINERAÇÃO DE DADOS DE IMAGENS OBTIDAS COM AERONAVE REMOTAMENTE PILOTADA PARA ESTIMATIVA DE PRODUTIVIDADE DO TRIGO

Gerke, Tiago 03 February 2017 (has links)
Made available in DSpace on 2017-07-21T14:19:29Z (GMT). No. of bitstreams: 1 TIAGO GERKE.pdf: 2494737 bytes, checksum: 62b5d2787dcdebe0e9ccf39bfa75f626 (MD5) Previous issue date: 2017-02-03 / Wheat cultivation plays an important role to Brazil and the world economic development, as well as in the human diet. The wheat Brazilian production is insufficient to meet the national demand, making research needed in order to improve the yield of this cereal. The goal of this work was to estimate wheat yield, searching for a predictive model through the data mining techniques, with data obtained from high spatial resolution images collected by unmanned aerial vehicles (UAV). The work was carried out in two experimental areas at Ponta Grossa city, Parana state, where for each area eight images were taken, at different culture development stages, with spatial resolution of 3.4cm/px and two images with resolution 10cm/px and 20cm/px, using an eBee UAV with an RGB and a NIR camera. The image processing was done with the Pix4D software, and resulted in an orthomosaics with reflectance values at different wavelengths: Red, Green and Blue, from the RGB camera and Red, Greed and NIR from the NIR camera, besides an image with NDVI values obtained from the arithmetic of NIR and Red wavelengths. The georeferencing correction of each orthomosaic and the extraction of the reflectance values were done with Quantum GIS geographic information system (GIS). From the extracted reflectance values, databases in different proportions (10%, 20%, 40%, 70% and 100%) were created for data mining, using the SMOReg algorithm, based on a support vector machine (SVM) for regression (SVR). The georreferencing correction using 10 control points provided ortomosaics with mean square error (RSME) of distance of 0.35m, which did not show significant difference compared to the correction with 5 control points (RMSE = 0.38m). The reflectance values were different for each study area, making it difficult to indicate better periods for estimating wheat yield. The highest correlation were obtained with data from RGB camera images, followed by the NIR and NDVI camera, with correlations of 0.6168,0.5423 and 0.5324, respectively. The amount of information extracted from the images, reflected in the proportion of the databases, was not significant to generated predictive models, as well as in the correlation indexes, which were statistically the same. Better correlation indices were obtained from the data extracted from the images with spatial resolution of 20cm/px, which suggests that high spatial resolution images may not be adequate for wheat yield estimation. / O cultivo do trigo desempenha um papel importante no desenvolvimento econômico de várias regiões do Brasil e do mundo, bem como na dieta humana. A produção brasileira do trigo é insuficiente para atender à demanda nacional, tornando necessárias pesquisas com intuito de melhorar a produtividade desse cereal. O objetivo desse trabalho foi a estimativa de produtividade do trigo, a partir da criação de modelos preditivos por meio da mineração de dados obtidos em imagens de alta resolução espacial, coletadas por aeronave remotamente pilotada (RPA). O trabalho foi realizado em duas áreas experimentais na cidade de Ponta Grossa – PR, onde para cada área foram feitas oito coletas de imagens, em diferentes estádios de desenvolvimento da cultura, com resolução espacial de 3,4cm/px e duas coletas com resolução 10cm/px e 20cm/px, através de uma RPA eBee utilizando uma câmera RGB e outra NIR. O processamento das imagens foi feito a partir do software Pix4D, e resultou em um ortomosaicos com os valores de refletância em diferentes comprimentos de onda: R, G e B da câmera RGB e R, G e NIR da câmera NIR, além de uma imagem com valores de NDVI obtidos a partir da aritmética das bandas Nir e Red (vermelho). A correção de georreferenciamento de cada ortomosaico e a extração dos valores de refletância foram feitas com auxílio do sistema de informação geográfica (SIG) Quantum GIS. A partir dos valores de refletância extraídos, foram criadas bases de dados em diferentes proporções (10%, 20%, 40%, 70% e 100%) para mineração de dados por meio do algoritmo SMOReg, baseado em máquina de vetor de suporte (SVM) para regressão (SVR). A correção de georreferenciamento utilizando 10 pontos de controle proporcionou ortomosaicos com erro médio quadrático (RSME) de distância de 0,35m, o qual não mostrou diferença significativa para a correção com 5 pontos de controle (RMSE = 0,38m). Os valores de refletância foram diferentes para cada área de estudo, tornando difícil a indicação de melhores períodos para a estimativa de produtividade do trigo. Os maiores índices de correlação da produtividade com os comprimentos de onda, foram obtidos com os dados das imagens da câmera RGB, seguido da câmera NIR e NDVI, com as correlações de 0,6168, 0,5423 e 0,5324, respectivamente. A quantidade de informação extraída das imagens, refletida na proporção das bases de dados, não se mostrou significativa nos modelos preditivos gerados, bem como nos índices de correlação, os quais foram estatisticamente iguais. Índices de correlação melhores foram obtidos a partir dos dados extraídos das imagens com resolução espacial de 20cm/px, o que sugere que imagens de alta resolução espacial podem não ser adequadas para estimativa de produtividade do trigo.
167

Pratiques de la communication médiée à distance et en co-présence dans le cadre du travail collaboratif / Communication practices mediated distance and co-presence in collaborative work

Bracco Haulet, Manuella 24 November 2017 (has links)
Cette thèse a pour objectif de comprendre l’articulation des TIC dans l’activité communicationnelle des organisations. Ce qui nous intéresse, est d’analyser comment l’usage des objets mettent en relation, en tension les acteurs dans l’action collective. L’objectif étant d’analyser comment le travail de coopération se construit à travers l’usage des TIC. Il s’agira de saisir les règles et les mécanismes de l’ordre social dans les actes de communication médiée par ordinateur et de cerner la manière dont l’usager négocie ses interactions dans les relations d’interdépendance que suppose le travail collectif.Notre problématique est de comprendre comment le salarié s’approprie les technologies pour communiquer ? Comment il négocie dans ses interactions au sein de micros-réseaux ? Quels sont les rôles qu’il s’attribue dans la théâtralisation de lui-même ?Notre travail de recherche s’inscrit dans le champ de la communication des organisations et plus précisément dans l’étude des approches communicationnelles de la communication médiée par ordinateur au sein des organisations.Ce qui nous intéresse dans notre étude est de saisir, l’articulation entre TIC et travail coopératif, c’est-à-dire de comprendre comment les salariés ajustent leurs usages des technologies pour reconstruire des systèmes de coopération à partir des outils mis à leur disposition. / This thesis has for objective to understand the joints of information and communication technologies in the communication activity organizations. What interests us, is to analyze how the use of objects put in relation, in tension, the actors in the collective action. The objective being to analyze how the work of cooperation builds itself through the use information and communication technology. It will be a question of seizing rules and mechanisms of the social order in the acts of communication mediatized by computer and of encircling well the way the user negotiates his interactions in the relations of interdependence which supposes the collective work.Our problem is to understand how the employee appropriates information and communication technologies? How he negotiates in his interactions within microcomputing- networks? What are the roles that he appropriates in the dramatization of himself?Our research work joins in the field of the communication of organizations and more exactly in the study of the communication approaches of the communication mediatized by computer within organizations.What interests us in our study is to seize, the joint between information and communication technologies and cooperative Work, that is to understand how the employees adjust their practices information and communication technologies to reconstruct systems of cooperation from tools arrangement.
168

Assimilation de données et inversion bathymétrique pour la modélisation de l'évolution des plages sableuses

Birrien, Florent 14 May 2013 (has links)
Cette thèse présente une plateforme d'assimilation de données issues de l'imagerie vidéo et intégrée au modèle numérique d'évolution de profil de plage 1DBEACH. Le manque de jeux de données bathymétriques haute-fréquence est un des problèmes récurrents pour la modélisation morphodynamique littorale. Pourtant, des relevés topographiques réguliers sont nécessaires non seulement pour la validation de nos modèles hydro-sédimentaires mais aussi dans une perspective de prévision d'évolution morphologique de nos plages sableuses et d'évolution de la dynamique des courants de baïnes en temps réel. Les récents progrès dans le domaine de l'imagerie vidéo littorale ont permis d'envisager un moyen de suivi morphologique quasi-quotidien et bien moins coûteux que les traditionnelles campagnes de mesure. En effet, les images dérivées de la vidéo de type timex ou timestack rendent possible l'extraction de proxys bathymétriques qui permettent de caractériser et de reconstruire la morphologie de plage sous-jacente. Cependant, ces méthodes d'inversion bathymétrique directes sont limitées au cas linéaire et nécessitent, selon les conditions hydrodynamiques ambiantes, l'acquisition de données vidéo sur plusieurs heures voire plusieurs jours pour caractériser un état de plage. En réponse à ces différents points bloquants, ces travaux de thèse proposaient l'implémentation puis la validation de méthodes d'inversion bathymétrique basées sur l'assimilation dans notre modèle de différentes sources d'observations vidéo disponibles et complémentaires. A partir d'informations hétérogènes et non redondantes, ces méthodes permettent la reconstruction rapide et précise d'une morphologie de plage dans son intégralité pour ainsi bénéficier de relevés bathymétriques haute fréquence réguliers. / This thesis presents data-model assimilation techniques using video-derived beach information to improve the modelling of beach profile evolution.The acquisition of accurate and recurrent nearshore bathymetric data is a difficult and challenging task which limits our understanding of nearshore morphological changes. This is particularly true in the surf zone which exhibits the largest degree of morphological variability. In addition, surfzone bathymetric data are crucial from many perspectives such as numerical model validation, operational rip current prediction or real-time nearshore evolution modelling. In parallel, video imagery recently arose as a low-cost alternative to direct measurement in order to daily monitor beach morphological changes. Indeed, bathymetry proxies can be extracted from video-derived images such as timex or timestacks. These data can be then used to estimate underlying beach morphologies. However, simple linear depth inversion techniques still suffer from some restrictions and require up to a 3-day dataset to completely characterize a given beach morphology. As an alternative, this thesis presents and validates data-assimilation methods that combine multiple sources of available video-derived bathymetry proxies to provide a rapid, complete and accurate estimation of the underlying bathymetry and prevent from excessive information.
169

Restabelecimento de energia por reconfiguração de redes em sistemas de distribuição de grande porte com priorização de chaves, consumidores e definição de sequência de chaveamento / Service restoration by network reconfiguration in large scale distribution systems with switches and consumers priorization and switching sequence definition

Leandro Tolomeu Marques 29 August 2013 (has links)
Na ocorrência de uma ou de múltiplas faltas permanentes em sistemas de distribuição de energia elétrica é inevitável a ausência de fornecimento à algumas cargas. Contudo, devido à presença de chaves seccionadoras, após a localização e isolação do trecho sob falta, é possível restaurar o abastecimento de energia a estas cargas fora de serviço. Para tal é necessária a obtenção de um plano de restabelecimento adequado, no menor intervalo de tempo possível, capaz de informar as chaves que devem ser operadas a fim de reconectar estas cargas à rede e sem sobrecarregar nenhum equipamento. Neste sentido, têm sido propostas metodologias para auxiliar as atividades dos operadores de sistemas de distribuição por meio do fornecimento de planos de restabelecimento de energia em situações de contingência. Todavia, a aplicação da maioria destas técnicas restringe-se à redes pequenas, quando comparadas às redes reais que possuem milhares de barras e chaves. Em outras metodologias, na tentativa de superar esta limitação, são feitas simplificações na representação da rede, desconsiderando alguns dos seus elementos. Nestes casos, a solução fornecida para a rede simplificada pode não ter o mesmo desempenho na rede em operação, o que compromete a confiabilidade dessas metodologias. Em outros métodos, ainda, a rede é representada com todas as suas barras e chaves, no entanto, deixam de considerar a presença de consumidores especiais, que exigem prioridade de fornecimento, bem como de chaves existentes na rede que podem ser operadas remotamente. Face ao exposto, propõe-se uma metodologia para determinação, em tempo real, de planos de restabelecimento de energia elétrica em sistemas de distribuição de grande porte em situações de uma ou de múltiplas faltas. Para lidar com os múltiplos objetivos deste problema, sendo alguns dele conflitantes entre si, esta será baseada em Algoritmos Evolutivos Multi-Objetivo, enquanto que a representação computacional sem simplificações da rede será proporcionada por uma codificação de dados apoiada na teoria de grafos e denominada Representação Nó-Profundidade. A fim de diminuir o tempo e o custo de implementação dos planos obtidos, será considerada e dado prioridade de manobra às chaves controladas remotamente, que podem ser alteradas do centro de operações. Será dado prioridade também ao fornecimento de energia de consumidores especiais. Por fim, para cada plano de restabelecimento fornecido será definida uma sequência factível de chaves que, quando alteradas, reconectarão as cargas sãs fora de serviço e eliminarão sobrecargas ou perfis de tensão inadequados. Para validar a metodologia proposta serão realizadas simulações computacionais no sistema de distribuição real da cidade de São Carlos-SP, em operação no ano de 1994, e nas suas versões duplicada, quadruplicada e octuplicada. / The occurrence of one or multiple permanent faults in electric power distribution systems is inevitable the privation of the service to some loads. However, due to the presence of switches, after the location and isolation of the faulted section, you can restore the power supply to these out of service loads. To this it is necessary to obtain, as soon as possible, a suitable restoration plan. It must be able to inform the switches that must be operated in order to reconnect these loads without overloading on any network or equipment. In this sense, it has been proposed methods to assist the operators\' activities of the of distribution systems by providing plans to restore the service in contingency situations. However, the application of the most of these techniques is limited to small networks, when they are compared to real networks that have thousands of bars and keys. In other methodologies, in order to overcome this limitation, simplications are made in the representation of the network, ignoring some of its elements. In these cases, the solution provided for a simplied network may not have the same performance on the network in operation, which aects the reliability of these methodologies. In other methods, the network is represented with all of its bars and switches. However, these methodologies do not consider the presence of the special consumers that require service priority neither the switches that can be operated remotely. Given the above, we propose a methodology for determining, in real time, plans for service restoration in large-scale electric distribution systems in situations of one or multiple faults. To deal with the multiple objectives of this problem, some of them con icting, the proposed method will be based on Multi-Objective Evolutionary Algorithms. Moreover, the computational representation without simplications of the network will be provided by a data encoding based in graph theory and called Node-Depth Encoding. In order to reduce the time and cost of the implementation of the plans obtained, it will be considered and given priority to maneuvers in remotely controlled switches, which can be changed from the operation center. Priority will be given also to the power supply of special consumers. Finally, for each restoration plan provided will be gotten a feasible switching sequence that, when implemented, will reconnect the out of service loads and eliminate overloads or inadequate voltage proles. To validate the proposed methodology it will be performed computer simulations in the real distribution system of the São Carlos-SP city, in operation in 1994, and their doubled, quadruplicate and octuplicate versions.
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Índice de vegetação por diferença normalizada (NDVI) para definição de zonas de manejo e monitoramento da variabilidade da sucessão aveia preta/soja / Normalized differential vegetation index (NDVI) for the definition of management zone and monitoring of variability of succession black oats / soybean

Damian, Júnior Melo 18 January 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The no-tillage system (SPD) was one of the main innovations in Brazilian agriculture, but there are still discussions about how to achieve and maintain its quality and sustainability. The management of SPD areas through management zones presents great potential for this purpose, since it integrates different variables in order to facilitate and increase the technical and computerized management of agricultural practices and consequently the reduction of polluting potencies in environments. Among the main variables used to delimit management zones are the chemical attributes, yield maps and recently the NDVI index. In this sense, with Article I, the objective was to delimit management zones through yield maps and NDVIs derived from satellite images in historical series. To do this, in an area of 118 ha, three yield maps of different cultures between the years of 2010 to 2015 were selected and for each yield map we searched for the images from the Landsat 5 and 8 satellite that included a date in of the cycle of the crop in question from which the NDVI was calculated and also with the intention of verifying the stability of the NDVI generated in different crop cycles, four other satellite images were selected for four crops according to the historical of the study area, between the years 2007 and 2013. In article II, the objective was to verify the variability caused by the winter cover crop in the summer crop and if the NDVI index performed by land and with a RPAS is able to evidence this variability in the summer crop. In an area 73.96 there was applied a sampling grid of 70.71 x 70.71 m (0.5 ha), where soil sampling for chemical analysis and dry matter nutrients accumulated in the winter cover crop of black oats where soybean was sown in the summer, in which in the R5 and R5.5 stages evaluations were carried out with a portable sensor "by land" and with a RPAS for obtaining of the NDVI index and finally the grain yield of the soybean was determined, as well as the final population of plants. With the results, NDVI from satellite images can replace and/or compose the yield maps (article I) and that the dry mass and accumulated nutrients in the winter crop interfere with the yield of the summer crop and the NDVI index performed by land or with a RPAS was effective in expressing this variability (article II). / O Sistema Plantio Direto (SPD) foi uma das principais inovações na agricultura brasileira, contudo ainda há discussões sobre como alcançar e manter sua qualidade e sustentabilidade. A gestão de áreas sob SPD por meio de zonas de manejo, apresenta grande potencial para essa finalidade, pois integra diferentes variáveis afim de facilitar e incrementar a gestão tecnificada e informatizada das práticas agrícolas, e em consequência a redução de potencias poluidores no ambiente. Entre as principais variáveis utilizadas para delimitar zonas de manejo estão os atributos químicos, mapas de rendimento e recentemente o índice NDVI. Nesse sentido, com o artigo I objetivou-se delimitar zonas de manejo por meio de mapas de rendimento e NDVI oriundos de imagens de satélite em series históricas. Para isso, em uma área de 118 ha, selecionou-se três mapas de rendimento de diferentes culturas compreendidas entre os anos de 2010 a 2015 e para cada mapa de rendimento buscou-se selecionar as imagens satélite oriundas série Landsat que compreendessem uma data dentro do ciclo da cultura em questão a partir das quais procedeu-se o cálculo do NDVI e ainda com o intuito de verificar a estabilidade do NDVI gerado em diferentes ciclos de cultivo, foram selecionadas outras quatro imagens de satélites referentes a quatro cultivos, segundo o histórico de cultivo da área de estudo, compreendidos entre os anos de 2007 a 2013. Já no artigo II, o objetivo foi verificar a variabilidade causada pela cultura de cobertura de inverno na cultura de verão e se o índice de NDVI realizado “por terra” e com um RPAS é capaz de evidenciar essa variabilidade na cultura de verão. Em uma área 73,96 ha, aplicou-se uma malha amostral de 70,71 x 70,71 m (0,5 ha), onde realizou-se a amostragem de solo para a análise química e as avaliações de matéria seca e os nutrientes acumulados na cultura de cobertura inverno da aveia preta onde sobre esta, foi semeada no verão a cultura da soja, na qual nos estágios R5 e R5.5 foram realizadas avaliações com um sensor portátil “por terra” e com um RPAS para a obtenção do índice de NDVI e por final determinou-se o rendimento de grãos da soja, bem como, a população final de plantas. Com os resultados, constatou-se que O NDVI foi um bom parâmetro para delimitar duas zonas de manejo de alto e baixo potencial (artigo I) e que a matéria seca e os nutrientes acumulados na cultura de inverno interferem o rendimento da cultura de verão, sendo que o índice de NDVI realizado “por terra” ou com um RPAS foi eficaz em expressar essa variabilidade (artigo II).

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