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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

Ανάπτυξη συστήματος επεξεργασίας δεδομένων τηλεπισκόπησης για αυτόματη ανίχνευση και ταξινόμηση περιοχών με περιβαλλοντικές αλλοιώσεις

Χριστούλας, Γεώργιος 31 May 2012 (has links)
Η παρούσα διατριβή είχε σαν κύριο στόχο την ανάλυση και επεξεργασία των δεδομένων SAR υπό το πρίσμα του περιεχομένου υφής για την ανίχνευση περιοχών με περιβαλλοντικές αλλοιώσεις όπως είναι οι παράνομες εναποθέσεις απορριμμάτων. Τα δεδομένα που χρησιμοποιήθηκαν προέρχονταν από τον δορυφόρο ENVISAT και το όργανο ASAR του Ευρωπαϊκού Οργανισμού Διαστήματος με διακριτική ικανότητα 12.5m και 30m για τις λειτουργίες μονής και διπλής πολικότητας αντίστοιχα καθώς και από τον δορυφόρο Terra-SAR με διακριτική ικανότητα 3m και HH πολικότητα. Χρησιμοποιήθηκαν κλασσικές τεχνικές ανάλυσης και ταξινόμησης υφής όπως GLCM, Markov Random Fields, Gabor Filters και Neural Networks. Η μελέτη προσανατολίστηκε στην ανάπτυξη νέων μεθόδων ταξινόμησης υφής για αυξημένη αποτελεσματικότητα. Χρησιμοποιήθηκαν δεδομένα πολυφασματικά και SAR. Για τα πολυφασματικά δεδομένα προτάθηκε η χρήση της spectral co-occurrence ως χαρακτηριστικό υφής που χρησιμοποιεί πληροφορία φασματικού περιεχομένου. Για τα δεδομένα SAR αναπτύχθηκε μία νέα μέθοδος ταξινόμησης η οποία βασίζεται σε συνήθεις περιγραφείς υφής (GLCM, Gabor, MRF) οι οποίοι μελετώνται για την ικανότητά τους να διαχωρίζουν ζεύγη μεταξύ τάξεων. Για κάθε ζεύγος τάξεων προκύπτουν χαρακτηριστικά υφής που βασίζονται στις στατιστικές ιδιότητες της cumulative καθώς και της πρώτης και δεύτερης τάξης αυτής. Η μέθοδος leave one out χρησιμοποιείται για τον εντοπισμό των χαρακτηριστικών που μπορούν να διαχωρίσουν τα δείγματα ανά ζεύγη τάξεων στα οποία αντιστοιχίζεται και ένας ξεχωριστός και ανεξάρτητος γραμμικός ταξινομητής. Η τελική ταξινόμηση γίνεται με τη μέθοδο της πλειοψηφίας η οποία εφαρμόζεται στο πρόβλημα των δύο τάξεων και τριών τάξεων αλλά επεκτείνεται και στο πρόβλημα των N-τάξεων δεδομένης της ύπαρξης κατάλληλων χαρακτηριστικών. / Texture characteristics of MERIS data based on the Gray-Level Co-occurrence Matrices (GLCM) are explored as far as their classification capabilities are concerned. Classification is employed in order to reveal four different land cover types, namely: water, forest, field and urban areas. The classification performance for each cover type is studied separately on each spectral band, while the combined performance of the most promising spectral bands is explored. In addition to GLCM, spectral co-occurrence matrices (SCM) formed by measuring the transition from band-to-band are employed for improving classification results. Conventional classifiers and voting techniques are used for the classification stage. Furthermore, the properties of texture characteristics are explored on various types of grayscale or RGB representations of the multispectral data, obtained by means of principal components analysis (PCA), non-negative matrix factorization (NMF) and information theory. Finally, the accuracy of the proposed classification approach is compared with that of the minimum distance classifier. A simple and effective classification method is furthermore proposed for remote sensed data that is based on a majority voting schema. We propose a feature selection procedure for exhaustive search of occurrence measures resulting from fundamental textural descriptors such as Co-occurrence matrices, Gabor filters and Markov Random Fields. In the proposed method occurrence measures, that are named texture densities, are reduced to the local cumulative function of the texture representation and only those that can linearly separate pairs of classes are used in the classification stage, thus ensuring high classification accuracy and reliability. Experiments performed on SAR data of high resolution and on a Brodatz texture database have given more than 90% classification accuracy with reliability above 95%.
162

Scene Analysis and Interpretation by ICA Based Polarimetric Incoherent Target Decomposition for Polarimetric SAR Data / Analyse et interprétation des données Radar à Synthèse d’Ouverture polarimétriques par des outils de type ACP-ICTD

Guimaraes figueroa pralon, Leandro 27 October 2016 (has links)
Cette thèse comprend deux axes de recherche. D´abord, un nouveau cadre méthodologique pour évaluer la conformité des données RSO (Radar à Synthèse d’Ouverture) multivariées à haute résolution spatiale est proposé en termes de statistique asymptotique par rapport au modèle produit. Plus précisément, la symétrie sphérique est étudiée en appliquant un test d'hypothèses sur la structure de la matrice de quadri-covariance. Deux jeux de données, simulées et réelles, sont prises en considération pour étudier la performance du test obtenu par l’analyse qualitative et quantitative des résultats. La conclusion la plus importante, en ce qui concerne la méthodologie employée dans l'analyse des données RSO multivariées, est que, selon les différents cas d’usages, une partie considérable de données hétérogènes peut ne pas s’ajuster asymptotiquement au modèle produit. Par conséquent, les algorithmes de classification et/ou détection conventionnels développés sur la base de celui-ci deviennent sub-optimaux. Cette observation met en évidence la nécessité de développer de modèles plus sophistiqués comme l'Analyse en Composantes Indépendantes, ce qui conduit à la deuxième partie de cette thèse qui consiste en l’étude du biais d’estimation des paramètres TSVM (Target Scattering Vector Model) lorsque l’ACP est utilisée. Enfin, les performances de l'algorithme sont également évaluées sous l'hypothèse du bruit gaussien corrélé spatialement. L’évaluation théorique de l'ACI comme un outil de type ICTD (In Coherent Target Decomposition) polarimétrique permet une analyse plus efficace de l’apport d’information fourni. A ce but, deux espaces de représentation sont utilisé, notamment H /alpha et TSVM / This thesis comprises two research axes. First, a new methodological framework to assess the conformity of multivariate high-resolution Synthetic Aperture Radar (SAR) data with respect to the Spherically Invariant Random Vector model in terms of asymptotic statistics is proposed. More precisely, spherical symmetry is investigated by applying statistical hypotheses testing on the structure of the quadricovariance matrix. Both simulated and real data are taken into consideration to investigate the performance of the derived test by a detailed qualitative and quantitative analysis. The most important conclusion drawn, regarding the methodology employed in analysing SAR data, is that, depending on the scenario under study, a considerable portion of high heterogeneous data may not fit the aforementioned model. Therefore, traditional detection and classification algorithms developed based on the latter become sub-optimal when applied in such kind of regions. This assertion highlights for the need of the development of model independent algorithms, like the Independent Component Analysis, what leads to the second part of the thesis. A Monte Carlo approach is performed in order to investigate the bias in estimating the Touzi's Target Scattering Vector Model (TSVM) parameters when ICA is employed using a sliding window approach under different scenarios. Finally, the performance of the algorithm is also evaluated under Gaussian clutter assumption and when spatial correlation is introduced in the model. These theoretical assessment of ICA based ICTD enables a more efficient analysis of the potential new information provided by the ICA based ICTD. Both Touzi TSVM as well as Cloude and Pottier H/alpha feature space are then taken into consideration for that purpose. The combined use of ICA and Touzi TSVM is straightforward, indicating new, but not groundbreaking information, when compared to the Eigenvector approach. Nevertheless, the analysis of the combined use of ICA and Cloude and Pottier H/alpha feature space revealed a potential aspect of the Independent Component Analysis based ICTD, which can not be matched by the Eigenvector approach. ICA does not introduce any unfeasible region in the H/alpha plane, increasing the range of possible natural phenomenons depicted in the aforementioned feature space.
163

Conception de circuits analogique-numérique pour le conditionnement de micro-capteurs embarqués / Analogical-digital circuits conception for embedded micro-sensors conditioning

Regis, Guillaume 13 January 2011 (has links)
Le domaine de l'instrumentation des capteurs est en constante évolution. Ce travail propose la conception des éléments clefs qui constituent les chaines d'instrumentations de capteurs d'aujourd'hui au travers de 3 applications concrètes. La première application est la mesure de vitesse et de position, par exemple dans un roulement. Nous présentons la conception et la réalisation d'un circuit analogique pour le conditionnement d'un capteur de type magnétorésistif. Ce capteur mesure le champ magnétique généré par les pôles magnétiques d'une roue codeuse. Le circuit est optimisé en bruit, en consommation et travaille sur une bande passante de plusieurs kHz. Pour compenser la dispersion des capteurs, le circuit permet des réglages d'offset et une calibration de gains. Il contient également une mémoire de type OTP (One Time Programmable Memory) qui sauvegarde les réglages associés au capteur. La deuxième application est la mesure de signaux de type EcoG afin d'interfacer le cerveau humain. Nous décrivons la conception et la réalisation d'un convertisseur Analogique/Numérique de type SAR. Il possède un convertisseur numérique analogique capacitif avec une capacité d'atténuation afin de réduire le nombre total de condensateur et ainsi la consommation. Le comparateur possède une entrée rail-to-rail et un système de préamplification avec auto zéro pour diminuer l'offset. Sa consommation est de 86µW pour une vitesse de 24Ks/S et 12bits de résolution. Enfin la troisième application est la mesure de pression stationnaire sur la voilure des avions afin d'en connaître les contraintes. Nous décrivons l'étude architecturale d'un convertisseur sigma-delta permettant d'atteindre une grande résolution pour des signaux de faible fréquence. Il sera de type incrémentale et répondra à des applications de type instrumentation de capteur. Sa résolution est de 16bits ENOB pour une fréquence maximale d'entrée de 100Hz et minimale de sortie d'1Ks/S. Le mode incrémental permettra d'obtenir une sortie en réponse à une requête de manière asynchrone. Une modélisation de chaque élément du système complet convertisseur plus capteur a été effectuée sous Matlab. L'étude de la partie filtrage numérique du convertisseur et l'optimisation de son implémentation numérique sont présentées. Cette étude architecturale complète aboutit au dimensionnement de chaque élément pour répondre au cahier des charges de l'application . / The domain of sensors instrumentation is constantly evolving. The present work proposes the design of the key elements conception which constitute the instrumentations chains of current sensors through 3 concrete applications. The first application is speed and position measurement, for example in a wheel bearing. We present the design and realization of an analogical circuit for the conditioning of magneto resistive sensor. This sensor measures the magnetic field generated by the coding wheel magnetic poles inside the bearing. The circuit is noise and power consumption optimized on a bandwidth of few kHz. To compensate sensors variability, the circuit includes offset regulations and gains. It also contains an OTP (One Time Programmable) memory which backs up the associated sensor regulations. The second application is the measurement of EcoG's signals to interface with the human brain. We describe the design and realization of SAR ADC. It is composed of a capacitive DAC with an attenuation capacitor to reduce the total number of condensers and, in doing so, to reduce power consumption. The comparator is composed by a rail-to-rail input and multistage preamplification and output offset storage. ADC total power consumption is 86µW for 24Ks/S speed and 12bits resolution. Finally the third application is the pressure measurement on aircraft wings. We describe the architectural study sigma-delta incremental ADC which reaches high resolution for low band pass signals. Its resolution is 16bits ENOB for a maximal input frequency of 100Hz and an output speed of 1Ks/S. The incremental mode leads to obtain output code in answer to asynchronous requests. Each system element (converter plus sensors) has been matlab modelled. The converter digital filtering study and its digital implementation optimization are presented. This complete architectural study concludes with the sizing of each element in order to answer the technical specifications of the application.
164

Aplica??o do sensoriamento remoto e do sistema de informa??es geogr?ficas na detec??o de manchas de ?leo na Regi?o do P?lo de Explora??o de Guamar?, R.N.

Albuquerque, Renata Costa Leite de 14 October 2004 (has links)
Made available in DSpace on 2015-03-13T17:08:24Z (GMT). No. of bitstreams: 1 RenataCLA.pdf: 1406363 bytes, checksum: c23d0993b7ed86a192397c6e7f6d9580 (MD5) Previous issue date: 2004-10-14 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Objective to establish a methodology for the oil spill monitoring on the sea surface, located at the Submerged Exploration Area of the Polo Region of Guamar?, in the State of Rio Grande do Norte, using orbital images of Synthetic Aperture Radar (SAR integrated with meteoceanographycs products. This methodology was applied in the following stages: (1) the creation of a base map of the Exploration Area; (2) the processing of NOAA/AVHRR and ERS-2 images for generation of meteoceanographycs products; (3) the processing of RADARSAT-1 images for monitoring of oil spills; (4) the integration of RADARSAT-1 images with NOAA/AVHRR and ERS-2 image products; and (5) the structuring of a data base. The Integration of RADARSAT-1 image of the Potiguar Basin of day 21.05.99 with the base map of the Exploration Area of the Polo Region of Guamar? for the identification of the probable sources of the oil spots, was used successfully in the detention of the probable spot of oil detected next to the exit to the submarine emissary in the Exploration Area of the Polo Region of Guamar?. To support the integration of RADARSAT-1 images with NOAA/AVHRR and ERS-2 image products, a methodology was developed for the classification of oil spills identified by RADARSAT-1 images. For this, the following algorithms of classification not supervised were tested: K-means, Fuzzy k-means and Isodata. These algorithms are part of the PCI Geomatics software, which was used for the filtering of RADARSAT-1 images. For validation of the results, the oil spills submitted to the unsupervised classification were compared to the results of the Semivariogram Textural Classifier (STC). The mentioned classifier was developed especially for oil spill classification purposes and requires PCI software for the whole processing of RADARSAT-1 images. After all, the results of the classifications were analyzed through Visual Analysis; Calculation of Proportionality of Largeness and Analysis Statistics. Amongst the three algorithms of classifications tested, it was noted that there were no significant alterations in relation to the spills classified with the STC, in all of the analyses taken into consideration. Therefore, considering all the procedures, it has been shown that the described methodology can be successfully applied using the unsupervised classifiers tested, resulting in a decrease of time in the identification and classification processing of oil spills, if compared with the utilization of the STC classifier / Objetiva o estabelecimento de uma metodologia para monitoramento de derramamento de ?leo no mar, na ?rea de Explora??o Submersa do P?lo de Guamar?, no Estado do Rio Grande do Norte, utilizando imagens orbitais de radares de abertura sint?tica (SAR) integradas aos produtos meteoceanogr?ficos. A aplica??o do modelo metodol?gico foi composto pelas seguintes etapas: (1) a cria??o de um mapa base da ?rea de Explora??o; (2) o processamento de imagens NOAA/AVHRR e ERS-2 para gera??o de produtos meteoceanogr?ficos; (3) o processamento de imagens RADARSAT-1 para monitoramento das manchas de ?leo; (4) a integra??o da imagem RADARSAT-1 com os produtos de imagens NOAA/AVHRR e ERS-2; e (5) a estrutura??o de um banco de dados. A Integra??o da imagem RADARSAT-1 da Bacia Potiguar do dia 21.05.99 com o mapa base da ?rea de Explora??o do P?lo de Guamar? para a identifica??o das prov?veis fontes das manchas de ?leo, foi utilizada com sucesso na detec??o da prov?vel mancha de ?leo detectada pr?xima ? sa?da do emiss?rio submarino na ?rea de Explora??o do P?lo de Guamar?. Para subsidiar a integra??o da imagem RADARSAT-1 com os produtos de imagens NOAA/AVHRR e ERS-2, desenvolveu-se uma metodologia para a classifica??o das manchas de ?leo identificadas em imagens RADARSAT-1. Nesta metodologia, testou-se os seguintes algor?tmos de classifica??o n?o-supervisionada: K-means, Fuzzy k-means e Isodata, que s?o parte integrante do software PCI Geomatics, o qual foi utilizado para a filtragem das imagens RADARSAT-1. Para a avalia??o dos resultados, as manchas de ?leo submetidas ? classifica??o n?o-supervisionada foram comparadas aos resultados do Classificador Textural por Semivariograma (STC), o qual foi desenvolvido especificamente para esta finalidade e requer a utiliza??o do software PCI Geomatics para efetuar parte do processamento das imagens RADARSAT-1. Por fim, os resultados das classifica??es foram analisados atrav?s de An?lise Visual; C?lculo de Proporcionalidade de Grandezas e An?lise Estat?stica. Dentre os tr?s algoritmos de classifica??o testados n?o houve significantes altera??es em rela??o as manchas classificadas pelo STC, em nenhuma das an?lises efetuadas. Os procedimentos adotados demonstraram que a metodologia descrita aqui poder? ser aplicada com sucesso, utilizando os classificadores n?o supervisionados testados, o que acarretaria em diminui??o de tempo no processo de identifica??o e classifica??o de manchas de ?leo, em compara??o ? utiliza??o do classificador STC
165

Sistema inteligente para detec??o de manchas de ?leo na superf?cie marinha atrav?s de imagens de SAR

Souza, Danilo Lima de 24 July 2006 (has links)
Made available in DSpace on 2014-12-17T14:56:21Z (GMT). No. of bitstreams: 1 DaniloLS.pdf: 2499617 bytes, checksum: 328b5ce6d56f5a92a61ad220565411c7 (MD5) Previous issue date: 2006-07-24 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Oil spill on the sea, accidental or not, generates enormous negative consequences for the affected area. The damages are ambient and economic, mainly with the proximity of these spots of preservation areas and/or coastal zones. The development of automatic techniques for identification of oil spots on the sea surface, captured through Radar images, assist in a complete monitoring of the oceans and seas. However spots of different origins can be visualized in this type of imaging, which is a very difficult task. The system proposed in this work, based on techniques of digital image processing and artificial neural network, has the objective to identify the analyzed spot and to discern between oil and other generating phenomena of spot. Tests in functional blocks that compose the proposed system allow the implementation of different algorithms, as well as its detailed and prompt analysis. The algorithms of digital image processing (speckle filtering and gradient), as well as classifier algorithms (Multilayer Perceptron, Radial Basis Function, Support Vector Machine and Committe Machine) are presented and commented.The final performance of the system, with different kind of classifiers, is presented by ROC curve. The true positive rates are considered agreed with the literature about oil slick detection through SAR images presents / Derramamentos de ?leo sobre o mar, mesmo que acidentais, geram enormes conseq??ncias negativas para a ?rea afetada. Os preju?zos s?o ambientais e econ?micos, principalmente com a proximidade dessas manchas de ?reas de preserva??o e/ou zonas costeiras. O desenvolvimento de t?cnicas autom?ticas para a identifica??o de manchas de ?leo sobre a superf?cie marinha, capturadas atrav?s de imagens de Radar, auxiliam num completo monitoramento dos oceanos e mares. Contudo, manchas de diferentes origens podem ser visualizadas nesse tipo de produ??o de imagem, tornando o monitoramento dif?cil. O sistema proposto neste trabalho, baseado em t?cnicas de processamento digital de imagens e redes neurais artificiais, tem o objetivo de identificar a mancha analisada e discernir entre ?leo e os demais fen?menos geradores de mancha. Testes nos blocos funcionais que comp?em o sistema proposto permitem a implementa??o de diferentes algoritmos, assim como sua an?lise detalhada e pontual. Os algoritmos que tratam do processamento digital de imagem (filtragem do ru?do speckle e gradiente), assim como o de classifica??o (Perceptron de M?ltiplas Camadas, rede de fun??o de Base Radial, M?quina de Vetor de Suporte e M?quina de comit?) s?o apresentados e comentados.O desempenho final do sistema, com diferentes tipos de classificadores, ? apresentado atrav?s da curva ROC. As taxas de acertos s?o consideradas condizentes com o que a literatura de detec??o de manchas de ?leo na superf?cie oce?nica atrav?s de imagens de SAR apresenta
166

Modelos de mistura de distribuições na segmentação de imagens SAR polarimétricas multi-look / Multi-look polarimetric SAR image segmentation using mixture models

Michelle Matos Horta 04 June 2009 (has links)
Esta tese se concentra em aplicar os modelos de mistura de distribuições na segmentação de imagens SAR polarimétricas multi-look. Dentro deste contexto, utilizou-se o algoritmo SEM em conjunto com os estimadores obtidos pelo método dos momentos para calcular as estimativas dos parâmetros do modelo de mistura das distribuições Wishart, Kp ou G0p. Cada uma destas distribuições possui parâmetros específicos que as diferem no ajuste dos dados com graus de homogeneidade variados. A distribuição Wishart descreve bem regiões com características mais homogêneas, como cultivo. Esta distribuição é muito utilizada na análise de dados SAR polarimétricos multi-look. As distribuições Kp e G0p possuem um parâmetro de rugosidade que as permitem descrever tanto regiões mais heterogêneas, como vegetação e áreas urbanas, quanto regiões homogêneas. Além dos modelos de mistura de uma única família de distribuições, também foi analisado o caso de um dicionário contendo as três famílias. Há comparações do método SEM proposto para os diferentes modelos com os métodos da literatura k-médias e EM utilizando imagens reais da banda L. O método SEM com a mistura de distribuições G0p forneceu os melhores resultados quando os outliers da imagem são desconsiderados. A distribuição G0p foi a mais flexível ao ajuste dos diferentes tipos de alvo. A distribuição Wishart foi robusta às diferentes inicializações. O método k-médias com a distribuição Wishart é robusto à segmentação de imagens contendo outliers, mas não é muito flexível à variabilidade das regiões heterogêneas. O modelo de mistura do dicionário de famílias melhora a log-verossimilhança do método SEM, mas apresenta resultados parecidos com os do modelo de mistura G0p. Para todos os tipos de inicialização e grupos, a distribuição G0p predominou no processo de seleção das distribuições do dicionário de famílias. / The main focus of this thesis consists of the application of mixture models in multi-look polarimetric SAR image segmentation. Within this context, the SEM algorithm, together with the method of moments, were applied in the estimation of the Wishart, Kp and G0p mixture model parameters. Each one of these distributions has specific parameters that allows fitting data with different degrees of homogeneity. The Wishart distribution is suitable for modeling homogeneous regions, like crop fields for example. This distribution is widely used in multi-look polarimetric SAR data analysis. The distributions Kp and G0p have a roughness parameter that allows them to describe both heterogeneous regions, as vegetation and urban areas, and homogeneous regions. Besides adopting mixture models of a single family of distributions, the use of a dictionary with all the three family of distributions was proposed and analyzed. Also, a comparison between the performance of the proposed SEM method, considering the different models in real L-band images and two widely known techniques described in literature (k-means and EM algorithms), are shown and discussed. The proposed SEM method, considering a G0p mixture model combined with a outlier removal stage, provided the best classication results. The G0p distribution was the most flexible for fitting the different kinds of data. The Wishart distribution was robust for different initializations. The k-means algorithm with Wishart distribution is robust for segmentation of SAR images containing outliers, but it is not so flexible to variabilities in heterogeneous regions. The mixture model considering the dictionary of distributions improves the SEM method log-likelihood, but presents similar results to those of G0p mixture model. For all types of initializations and clusters, the G0p prevailed in the distribution selection process of the dictionary of distributions.
167

Avaliação dos efeitos das hipertermias magnética e fototérmica na síntese de heteroestruturas à base de nanopartículas de MnFe2O4 e Au / Evaluation of the effects of magnetic and photothermal hyperthermia on the synthesis of heterostructures based on MnFe2O4 and Au nanoparticles

Sousa Júnior, Ailton Antônio de 14 December 2015 (has links)
Submitted by Cássia Santos (cassia.bcufg@gmail.com) on 2017-03-03T10:47:21Z No. of bitstreams: 2 Dissertação - Ailton Antônio de Sousa Júnior - 2015.pdf: 8825071 bytes, checksum: 2c6c25961d11096534c7e36baa42c260 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2017-03-03T11:52:36Z (GMT) No. of bitstreams: 2 Dissertação - Ailton Antônio de Sousa Júnior - 2015.pdf: 8825071 bytes, checksum: 2c6c25961d11096534c7e36baa42c260 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2017-03-03T11:52:36Z (GMT). No. of bitstreams: 2 Dissertação - Ailton Antônio de Sousa Júnior - 2015.pdf: 8825071 bytes, checksum: 2c6c25961d11096534c7e36baa42c260 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-12-14 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Conselho Nacional de Pesquisa e Desenvolvimento Científico e Tecnológico - CNPq / Fundação de Amparo à Pesquisa do Estado de Goiás - FAPEG / The purpose of this project is to synthesize and characterize heterostructures composed by manganese ferrite nanoparticles (MnFe2O4 NPs) and gold nanoparticles (Au NPs) able to: 1) respond to external alternating magnetic fields, what would enable their use in cancer diagnostic as contrast agentes for magnetic resonance imaging, as well as in cancer treatment via magnetic hyperthermia; 2) respond to eletromagnetic radiation, what would enable their use in cancer diagnostic as contrast agents for X-ray computed tomography (CT), as well as in cancer treatment via photothermal hyperthermia. We evaluate four MnFe2O4-Au heterostructures synthesis protocols. On Protocol 1, we use part of the energy of a laser beam (808 nm, 800 mW) to promote the nucleation of Au NPs at the surface of previously synthesized MnFe2O4 NPs covered by DMSA (dimercaptosuccinic acid). On Protocol 2, we use part of the energy of an alternating magnetic field (333,8 kHz, 17 mT) to promote this nucleation. We also perform an analysis of the influence of MnFe2O4 NPs covering layer, by comparing the ionic surfactants DMSA and sodium citrate. On Protocols 3 and 4, both the magnetic cores (MnFe2O4 NPs) and the metalic cores (Au NPs) are previously synthesized. Therefore, three Au NPs synthesis methods are evaluated. On Protocol 3, we promote the coupling between Au NPs and MnFe2O4-DMSA NPs using part of the energy from the same laser beam used on Protocol 1. On Protocol 4, we promote the coupling between cysteine-covered Au NPs and lysine-covered MnFe2O4 NPs via peptidic reaction between these two aminoacids. Finally, we conduct a comparative analysis between magnetic and photothermal hyperthermia, proposing a method for the determination of the optical SLP (Specific Loss Power). Moreover, we submit some of our samples to CT imaging. Protocol 1 is the best one in terms of covering the magnetic core by Au NPs. Protocol 2 allows the nucleation of Au NPs with diameters greater than the ones obtained via Protocol 1. Protocols 3 and 4 offer nanostructures with better potential with respect to their use as contrast agents in CT. However, the final yield of all four protocols is very low. Comparing magnetic and photothermal hyperthermia, we verify that the optical SLP is two to three orders of magnitude greater than the magnetic SLP under the assessed conditions, what suggests that protocols using laser beams have more energy available for the nucleation/coupling of Au NPs at the surface of MnFe2O4 NPs than those using alternating magnetic fields or simple heating on hot plate. / Este trabalho tem por objetivo sintetizar e caracterizar heteroestruturas compostas por nanopartículas de ferrita de manganês (NPs de MnFe2O4) e nanopartículas de ouro (NPs de Au), capazes de: 1) responder à aplicação de um campo magnético alternado, podendo ser utilizadas no diagnóstico de cânceres enquanto agentes de contraste no imagiamento por ressonância magnética, bem como em seu tratamento via hipertermia magnética; 2) responder à aplicação de radiação eletromagnética, podendo ser utilizadas no diagnóstico de cânceres como agentes de contraste no imagiamento por tomografia computadorizada de raios-X (CT), bem como em seu tratamento via hipertermia fototérmica. Nesse sentido, avaliamos quatro protocolos de síntese de heteroestruturas MnFe2O4-Au. No Protocolo 1, utilizamos parte da energia de um feixe de luz laser (808 nm, 800 mW) para promover a nucleação de NPs de Au à superfície de NPs de MnFe2O4 previamente sintetizadas, recobertas por DMSA (ácido dimercaptosuccínico). No Protocolo 2, utilizamos parte da energia de um campo magnético alternado (333,8 kHz, 17 mT) para promover essa nucleação. Fazemos também uma análise da influência da camada de cobertura das NPs de MnFe2O4, comparando os surfactantes iônicos DMSA e citrato de sódio.Nos Protocolos 3 e 4, tanto os núcleos magnéticos (NPs de MnFe2O4) quanto os núcleos metálicos (NPs de Au) são previamente sintetizados. Para tanto, três métodos de síntese de NPs de Au são avaliados. No Protocolo 3, promovemos o acoplamento de NPs de Au a NPs de MnFe2O4-DMSA utilizando parte da energia proveniente do mesmo feixe de luz laser utilizado no Protocolo 1. No Protocolo 4, promovemos o acoplamento de NPs de Au recobertas por moléculas cisteína a NPs de MnFe2O4 recobertas por moléculas de lisina via reações peptídicas entre esses dois aminoácidos. Finalmente, fazemos um estudo comparativo entre hipertermia magnética e hipertermia fototérmica, sugerindo um método para determinação do SLP (Specific Loss Power) óptico. Além disso, submetemos algumas de nossas amostras ao imagiamento por CT. O Protocolo 1 é o melhor do ponto de vista do recobrimento do núcleo magnético por NPs de Au. O Protocolo 2 permite a nucleação de NPs de Au com diâmetros superiores àqueles obtidos via Protocolo 1. Os Protocolos 3 e 4 oferecem nanoestruturas com melhor potencial quanto à sua utilização como agentes de contraste em CT. Entretanto, o rendimento de todos os protocolos avaliados é muito baixo. Na comparação entre hipertermia magnética e fototérmica, verificamos que o SLP óptico é de duas a três ordens de grandeza superior ao SLP magnético nas condições avaliadas, o que indica que protocolos que fazem uso de luz laser dispõem de mais energia para a nucleação/acoplamento de NPs de Au à superfície de NPs de MnFe2O4 do que aqueles que fazem uso de campos magnéticos alternados ou simples aquecimento em chapa térmica.
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Contribuição ao estudo da vegetação da porção leste da Ilha de Marajó / Contribution to the vegetation\'s study of the eastern portion of Marajo Island

Carlos Tadeu de Carvalho Gamba 11 February 2010 (has links)
A manutenção dos ecossistemas florestais da Amazônia é, sem dúvida, de suma importância para preservação da biodiversidade do planeta. Utilizar e avaliar dados de última geração que forneçam informações sobre estes ecossistemas torna-se então fundamental para o gerenciamento dos mesmos. Projeto pioneiro realizado na década de 1970, o RADAM teve como objetivo levantar, a partir de imagens de RADAR obtidas na banda X, informações sobre os recursos naturais da Amazônia. O avanço dos sistemas sensores baseados nas tecnologias de RADAR (Radio Detection and Ranging), com a introdução de plataformas capazes de imagear a superfície em comprimentos de onda maiores e em mais de uma polarização, trouxe uma nova perspectiva no campo de estudo destes recursos. Este trabalho emergiu a partir da constatação da necessidade, e possibilidade, de se obter informações mais precisas e atualizadas sobre o ambiente amazônico, levando em conta, inclusive, a velocidade das transformações que recaem sobre essa região. O objetivo primário do estudo foi analisar o potencial das imagens produzidas pelos radares de abertura sintética (SAR) nas bandas L e nas polarizações HH, HV e VV, na avaliação de tipologias vegetais da porção leste da Ilha de Marajó. Entendemos que essa pequena parcela do ambiente amazônico nos cede uma chave de padrões de classificação que podem ser replicados em outras regiões da Amazônia Legal, ou mesmo, em novos projetos de mapeamento similares ao RADAM. Os resultados obtidos por meio de análises das imagens de radar e através do estudo de diversas propostas de classificação fitogeográfica, evidenciaram um alto potencial de utilização destes recursos, bem como a possibilidade de avançarmos na escala de análise, produzindo mapeamentos de maior detalhe e mais abrangentes do ponto de vista das classes vegetais. A tecnologia para incrementar o mapeamento da região amazônica, de forma mais criteriosa e precisa, já existe há algum tempo e está disponível às instituições nacionais. Dar esse salto, importantíssimo para o conhecimento, preservação e monitoramento daquele que é considerado hoje o bioma mais importante do mundo, só depende de uma mudança nos critérios e de uma atualização das ferramentas usadas até o momento. / The maintenance of forest ecosystems in the Amazon is undoubtedly of great importance to the preservation of the planets biodiversity. The utilization and analysis of last generation data about these ecosystems become fundamental for their management. A pioneer project in the 1970 decade, the RADAM project had the objective of gathering information about Amazon natural resources from RADAR images obtained in the band X. The progress in sensor systems based on RADAR (Radio Detection and Ranging) technologies, with the introduction of platforms capable of imaging the surface in bigger wavelengths and in more than one polarization, brought a new perspective in the study area of these resources. This work emerged from the constatation of the need and possibility of obtaining more precise and updated information about the Amazon environment, inclusive considering the speed of the transformations that occur in this region. The primary objective of the study was to analyze the potential of the produced images by Synthetic Aperture Radars (SAR) in bands L and in polarizations HH, HV and VV, for the evaluation of vegetal typology of the east portion of Marajo Island. We understand that this little portion of the Amazon environment gives us a key of classification patterns that can be reapplied in other regions of Legal Amazon, or even in new mapping projects similar to RADAM. The results obtained from radar images analysis and through the study of several propositions for phytogeographic classification evidenced a high potential for the utilization of these resources, as well as the possibility of making progresses in the analysis scale, producing more detailed and comprehensive mappings from the point of view of vegetal classes. The technology to improve the mapping of Amazon region in a more criterious and precise manner has already existed for some time now and is available for national institutions. Making this leap, greatly important to knowledge, preservation and monitoring of what is considered the most important biome in the world only depends on a change in criteria and an updating of the tools that have been used up to this moment.
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Cronologia e sedimentologia dos depósitos eólicos quaternários da costa catarinense entre Ouvidor e Florianópolis

Vinicius Ribau Mendes 04 May 2012 (has links)
Dentro da região litorânea central do Estado de Santa Catarina, compreendida entre as praias do Ouvidor e dos Ingleses, foram delimitadase estudadas cinco áreas que abrigam tanto campos de dunas ativos quanto estabilizados. Com base em dados meteorológicos obtidos de 1962 a 2010, como registros diários de precipitação e deintensidade e rumo de vento, inferiu-se que a tendência de estabilização recente, observada nos campos de dunas atuais por comparação de fotografias aéreas de diferentes datas, resulta da combinação de aumento da precipitação com redução da intensidade do vento. Este dois fatores inibem o transporte eólico de sedimentos para o campo de dunas, seja pelo efeito de aumento de coesão da areia exercido pela umidade seja pelo favorecimento da colonização vegetal nas zonas de deflação. Persistentes nas últimas três décadas, estes fatores têm reduzido gradualmente as áreas deareia expostas ao retrabalhamento eólico, o que diminui cada vez mais a deriva eólica efetiva, culminando na fixação dos campos de dunas. Os depósitos sedimentares de dunas e paleodunas eólicas foram agrupados, por critérios morfológicos, estratigráficos, granulométricos e mineralógicos, em quatro gerações (G1 a G4), correlatas às reconhecidas previamente na literatura. A geração mais antiga (G1) possui, todavia, distribuição de idades mais ampla do que se pensava, podendo portanto, por critérios geocronológicos, vir a ser subdividida. Os resultados sedimentológicos apontam para tendências de engrossamento, melhora de seleção granulométrica e assimetria mais positiva, da geração mais antiga para a mais nova, o que é atribuído a influência de sucessiva reciclagem de sedimentos entre as gerações, sem descartar o efeito, em paralelo, de mudanças de energia e/ou morfodinâmica costeira. As idades obtidas para as gerações antigas pelo método da luminescência opticamente estimulada (LOE) permitem observar certa coincidência com contextos de linha de costa estável e de clima em transição de menos úmido para mais úmido. A relação observada entre as idades LOE obtidas e as curvas de variação do nível relativo do mar (NRM) e de paleopluviosidade, associadas ao modelo de estabilização de dunas recentes por aumento de umidade e queda de energia eólica, permite sugerir que a iniciação dos campos de dunas costeiros da região, em suas diferentes gerações, seja favorecida por situações de NRM estável e/ou em inversão de tendência, e por clima menos úmido e mais ventoso. A estabilização dos campos de dunas, em contrapartida, seria favorecida pela subida de NRM, pelo aumento da chuva e pela diminuição da intensidade dos ventos. Do ponto de vista do controle climático, a condição de iniciação de campos de dunas mencionadacoincidiria com momentos de enfraquecimento do Sistema de Monções da América doSul (SMAS), correlatos a períodos mais quentes no hemisfério norte. E a condição favorávelà estabilização de campos de dunas ocorreria nos momentos de intensificação do SMAS, correlatos a períodos mais frios no hemisfério norte. / This master dissertation refers to five areas withactive and stabilized eolian dune fields in the central coast of the Santa Catarina State, southernBrazil. In this region, a recent tendency to stabilization of active dune fields is inferred from the comparison between aerial photographs of different years. Meteorological data obtained between 1962 and 2010, including daily records of rainfall, wind intensity and wind direction, indicate increasing precipitation and weakening wind to this period. The combination of these two factors inhibits the eolian sediment transport to the dune field, as effect of increasing sand cohesion by wetting and vegetal colonization in deflation zones. Being persistent in the last three decades, these factorshave reduced gradually the sand areas exposed to eolian reworking and decreased more and more the effective eolian drift, culminating in the stabilization of dune fields. The sedimentary deposits of eolian dunes and paleodunes were grouped, by morphological, stratigraphic, granulometric and mineralogical criteria in four generations (G1 to G4), analogous to that previously recognized in the literature. The older generation (G1) has a wider age distribution than previously thought and can be subdivided regarding the geochronological aspect. The grain-size analysis data indicate trends of sediment coarsening, better sorting and more positive skewness, from the older to the younger generation,what is attributed to the influence of successive reworking of sediments between generations, withoutdiscarding the effect of changes in the transport energy and/or beach morphodynamics. The ages of the three older generations obtained by optically stimulated luminescence (OSL) method show coincidence with contexts of stable coastline and with climate in transition from less to more wet. The observed relationship between the OSL ages andthe relative sea level (RSL) and paleoprecipitation curves, besides the model of recent dune stabilization by the wet increasing and wind energy decreasing, allow us to suggest that the initiation of the dune fields in their different generations, in this coastal region, can be favoredby moments of stable and / or in reversal trend RSL, as well by less humid and more windy weather. In other hand, the stabilization of the dune fields would be favored by higher RSL, increasing rain and decreasing wind intensity. From the perspective of climate control, the mentioned condition to initiation of dune fields agree with moments of weakening of the South America Summer Monsoon System (SASM), related to warmer periods in the northern hemisphere. Analogously, the favorablecondition for the stabilization of dune fields would coincide with moments of intensification of the SASM, related to colder periods in the northern hemisphere.
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Ácido Salicílico, abcísico e jasmônico em videiras submetidas ou não à aplicação da tecnologia TPC (Thermal Pest Control) / Salicylic acid, abscisic acid and jasmonic acid in vines submitted or not to the application of TPC technology (Thermal Pest Control)

Bruno Alves Domingues 16 May 2013 (has links)
A aplicação de ar quente em videiras foi primeiramente realizada na fazenda do Sr. Florenzo Lazo, localizada no Chile, onde havia a necessidade de combater os efeitos negativos das freqüentes geadas que resultava em severos danos à lavoura. Por este motivo o Sr. Florenzo inventou uma máquina que aplicava ar quente com baixa umidade e tinha por objetivo dispersar o ar frio proveniente das geadas. Após certo tempo, foi observado pelo produtor que no local onde a máquina havia operado com maior frequência as plantas apresentavam-se com uma coloração mais escura e com sinais de maior vitalidade. Seguindo estas observações, relacionamos estes efeitos a um possível aumento nos fito-hormônios relacionados ao estresse vegetal e à SAR (Systemic Resistence Adquired), como o ácido salicílico (AS), ácido jasmônico (AJ) e ácido abscísico (ABA), além de fazer uma correlação com alguns resultados de pós-colheita importantes para a comercialização, como: Sólidos solúveis, firmeza e coloração. Para isso foi montado um experimento que foi conduzido em duas parcelas, sendo uma com tratamento TPC e outra apenas com o tratamento convencional com distância padronizada em 3,2 metros entre linhas por 2,0 metros entre planta. As amostras eram coletadas diariamente e devidamente acondicionadas. Ao final da safra, as amostras foram transportadas para o laboratório de estresse e neurofisiologia da universidade de São Paulo (LEPSE), onde foram novamente armazenadas em um Ultra-freezer - 86ºC. As analises fisiológicas de pós-colheita foram realizadas no departamento de pós-colheita da universidade de São Paulo onde foram analisados os teores de sólidos solúveis, coloração e firmeza das bagas de uva. As amostras de folhas foram maceradas e uniformizadas no LEPSE e enviadas para o laboratório de ecotoxicologia do Centro de Energia Nuclear na Agricultura (CENA) onde foram mensurados os teores dos fito-hormônios pelo método de espectrometria de massa. Para ambas as analises foram feitos testes estatísticos utilizando o programa SAS®. Não houve alteração de SS e firmeza entre os dois tratamentos para as características fisiológicas de póscolheita. Entretanto foi notado uma redução na coloração avermelhada para os cachos tratados com TPC seguindo o sistema de colorimetria proposto pelo CIE. Não houve alterações significantes para as variáveis ABA, AJ e AS para o efeito tratamento e para a analise de correlação. Entretanto notou-se significância entre o efeito dias para as variáveis ABA e AJ. Não foi notada significância para o efeito dias para a variável AS. Por se tratar de um estresse rápido, a TPC parece não causar estresse imediato nas plantas, entretanto notou-se indução de estresse ao longo do tempo, possivelmente devido à resposta lenta de ABA que aparentemente está envolvida com RNA e à síntese de proteínas S e R- ABA que são igualmente efetivas. Já para o AJ sugere-se que houve a produção de H2O2 por derivados de oligogalacturonideos, liberados por ação da enzima poligalacturonase, e um segundo mensageiro que ativam genes defensivos (genes tardios). O aumento na biossíntese do ABA e do AJ parece ter suprimido genes envolvidos na biossíntese do AS. / The application of hot air in grapevines was first held on the farm of Mr. Florenzo Lazo, located in Chile, to combat the negative effects of frequent frosts that resulted in severe damage to the crop. For this reason Mr. Florenzo invented a machine that applied hot air with low humidity and aimed to disperse the cold air from the frost. After a while, it was observed by the producer that where the machine had operated more frequently plants showed up with a darker and more signs of vitality. Following these observations, these effects relate to a possible increase in phytohormones related to plant stress and SAR (Systemic Resistance Adquired), such as salicylic acid (AS), jasmonic acid (AJ) and abscisic acid (ABA), besides making a correlation with results of some important postharvest for marketing, such as soluble solids, firmness and color. For this experiment was created that was conducted in two installments, the first one was treated with TPC and second one was applied only conventional treatment with standardized distance of 3.2 meters between lines by 2.0 meters between plant . The samples were collected daily and properly packed. At the end of the season, samples were transported to the laboratory stress and neurophysiology from the University of São Paulo (LEPSE), where they were again stored in an Ultra-freezer - 86 degrees. The physiological analyses of post-harvest were performed at the Department of Postharvest in University of Sao Paulo where we analyzed the levels of soluble solids, firmness and color in grape berries. The leaf samples were uniform macerated at LEPSE and sent to the laboratory of ecotoxicology in the Center for Nuclear Energy in Agriculture (CENA) where we measured the levels of the phytohormones by the method of mass spectrometry. For both analyzes were performed statistical tests using SAS ® program. There wasn`t change between the two treatments on physiological post-harvest characteristics. There was no change of SS and firmly between the two treatments for the physiological of post-harvest characteristics. However it was noted a reduction in red color for bunches treated with TPC following the colorimetry system by CIE. There were no significant changes to the variables ABA, AJ and AS for the treatment effect and to analyze the correlation. However significance was noted between the effect variables ABA days and AJ. No significant effect was noted for days variable for AS. Since it is a stress fast TPC does not seem to cause immediate stress in plants but it was noticed induction of stress over time, possibly due to slow response to ABA which apparently is involved in the synthesis of RNA and proteins S and R-ABA that are equally effective. As for AJ suggests that there was the production of H2O2 by derivatives of oligogalacturonides, released by action of the enzyme polygalacturonase, and a second messenger that activates defensive genes (late genes). The increase in ABA biosynthesis and AJ appears to have deleted genes involved in the biosynthesis of AS.

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