Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal. / Le genre Aster (Asteraceae, Astereae) contient approximativement 250 espèces, dont 150 d'origine nord-américaine. L'Eurasie, l'Amérique du Sud et l'Afrique se partagent le reste du genre (Brouillet, 1981). Aster cordifolius L. appartient à la sous-section Heterophylli (x=8), section Dumosi (x=8), du sous-genre Aster (x=7, 8, 9) (Semple & Brouillet, 1980a, b). C'est une espèce indigène de l'Amérique du Nord confinée à la région appalachienne du continent (Rousseau, 1974). Quatre taxons infraspécifiques sont rapportés au Québec : A. cordifolius L. var. cordifolius, var. polycephalus Porter, var. racemiflorus Fern. et var. Furbishiae Fern. (Fernald, 1950). Deux races chromosomiques (2n=16, 32) sont connues chez l'espèce (Jones, 1977) et leur patron de distribution est fort complexe (Brouillet, 1983a). Le but de cette étude est de définir la distribution des cytotypes de Aster cordifolius L. au Québec et de vérifier la validité des taxons infraspécifiques décrits par Fernald (1950). Nos travaux de cytologie, la morphométrie et les comparaisons sur le terrain nous permettent de tirer les conclusions suivantes : Au Québec, Aster cordifolius L. est constitué de deux cytotypes (2n=16, 32). Les diploïdes sont significativement différents des tétraploïdes pour 6 des variables étudiées. Les variétés Furbishiae Fern., racemiflorus Fern. et polycephalus Porter décrites dans la littérature sont des phénotypes environnementaux et ne méritent pas le statut de variété.

Die folgende Arbeit ist Teil des multidisziplinären Projektes DESERT (DEad SEa Rift Transect), welches seit dem Jahr 2000 im Nahen Osten durchgeführt wird. Dabei geht es primär um die Struktur der südlichen Dead Sea Transform (DST; Tote-Meer-Transformstörung), Plattengrenze zwischen Afrika (Sinai) und der Arabischen Mikroplatte. Seit dem Miozän beträgt der sinistrale Versatz an dieser bedeutenden aktiven Blattverschiebung mehr als 100 km. Das steilwinkelseismische (NVR) Experiment von DESERT querte die DST im Arava Tal zwischen Rotem Meer und Totem Meer, wo die Hauptstörung auch Arava Fault genannt wird. Das 100 km lange Profil erstreckte sich von Sede Boqer/Israel im Nordwesten nach Ma'an/Jordanien im Südosten und fällt mit dem zentralen Teil einer weitwinkelseismischen Profillinie zusammen. <br><br> Steilwinkelseismische Messungen stellen bei der Bestimmung der Krustenstruktur bis zur Krusten/Mantel-Grenze ein wichtiges Instrument dar. Obwohl es kaum möglich ist, steilstehende Störungszonen direkt abzubilden, geben abrupte Veränderungen des Reflektivitätsmuster oder plötzlich endende Reflektoren indirekte Hinweise auf Transformbewegung. Da bis zum DESERT Experiment keine anderen reflexionsseismischen Messungen über die DST ausgeführt worden waren, waren wichtige Aspekte dieser Transform-Plattengrenze und der damit verbundenen Krustenstruktur nicht bekannt. Mit dem Projekt sollte deshalb untersucht werden, wie sich die DST sowohl in der oberen als auch in der unteren Kruste manifestiert. Zu den Fragestellungen gehörte unter anderem, ob sich die DST bis in den Mantel fortsetzt und ob ein Versatz der Krusten/Mantel-Grenze beobachtet werden kann. So ein Versatz ist von anderen großen Transformstörungen bekannt. <br><br> In der vorliegenden Arbeit werden zunächst die Methode der Steilwinkelseismik und die Datenverarbeitung kurz erläutert, bevor die Daten geologisch interpretiert werden. Bei der Interpetation werden die Ergebnisse anderer relevanter Studien berücksichtigt. Geologische Geländearbeiten im Gebiet des NVR Profiles ergaben, dass die Arava Fault zum Teil charakterisiert ist durch niedrige Steilstufen in den neogenen Sedimenten, durch kleine Druckrücken oder Rhomb-Gräben. Ein typischer Aufbau der Störungszone mit einem Störungskern, einer störungsbezogenen Deformationszone und einem undeformierten Ausgangsgestein, wie er von anderen großen Störungszonen beschrieben worden ist, konnte nicht gefunden werden. Deshalb wurden zur Ergänzung der Reflexionsseismik, welche vor allem die tieferen Krustenstrukturen abbildet, ASTER (Advanced Spacebourne Thermal Emission and Reflection Radiometer) Satellitendaten herangezogen, um oberflächennahe Deformation und neotektonische Aktivität zu bestimmen. / Following work is embedded in the multidisciplinary study DESERT (DEad SEa Rift Transect) that has been carried out in the Middle East since the beginning of the year 2000. It focuses on the structure of the southern Dead Sea Transform (DST), the transform plate boundary between Africa (Sinai) and the Arabian microplate. The left-lateral displacement along this major active strike-slip fault amounts to more than 100 km since Miocene times. The DESERT near-vertical seismic reflection (NVR) experiment crossed the DST in the Arava Valley between Red Sea and Dead Sea, where its main fault is called Arava Fault. The 100 km long profile extends in a NW&mdash;SE direction from Sede Boqer/Israel to Ma'an/Jordan and coincides with the central part of a wide-angle seismic refraction/reflection line. <br><br> Near-vertical seismic reflection studies are powerful tools to study the crustal architecture down to the crust/mantle boundary. Although they cannot directly image steeply dipping fault zones, they can give indirect evidence for transform motion by offset reflectors or an abrupt change in reflectivity pattern. Since no seismic reflection profile had crossed the DST before DESERT, important aspects of this transform plate boundary and related crustal structures were not known. Thus this study aimed to resolve the DST's manifestation in both the upper and the lower crust. It was to show, whether the DST penetrates into the mantle and whether it is associated with an offset of the crust/mantle boundary, which is observed at other large strike-slip zones. <br><br> In this work a short description of the seismic reflection method and the various processing steps is followed by a geological interpretation of the seismic data, taking into account relevant information from other studies. Geological investigations in the area of the NVR profile showed, that the Arava Fault can partly be recognized in the field by small scarps in the Neogene sediments, small pressure ridges or rhomb-shaped grabens. A typical fault zone architecture with a fault gauge, fault-related damage zone, and undeformed host rock, that has been reported from other large fault zones, could not be found. Therefore, as a complementary part to the NVR experiment, which was designed to resolve deeper crustal structures, ASTER (Advanced Spacebourne Thermal Emission and Reflection Radiometer) satellite images were used to analyze surface deformation and determine neotectonic activity.

Submitted by Setor de Tratamento da Informa??o - BC/PUCRS (tede2@pucrs.br) on 2015-04-24T14:07:47Z No. of bitstreams: 1 467627 - Texto Completo.pdf: 2210744 bytes, checksum: aad8668a5522012bd1f3603c51df5d00 (MD5) / Made available in DSpace on 2015-04-24T14:07:47Z (GMT). No. of bitstreams: 1 467627 - Texto Completo.pdf: 2210744 bytes, checksum: aad8668a5522012bd1f3603c51df5d00 (MD5) Previous issue date: 2015-03-25 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / The Baccharis genus has more than 500 species discribed and 90% occur in South America. It has highlighted important feature in the folk medicine being used for digestive problems. Studies report the presence of phenolic compounds and phenolic acids in its non-volatile extracts. Non-volatile extracts are obtained by infusion and/or maceration of parts of the plant in solvent. One way to obtain pure extracts without the need of evaporation of the solvent is the extraction by supercritical fluid. The aim of the present study was to obtain non-volatile compounds of seven Baccharis species: Baccharis microdonta, B. megapotamica, B. vulneraria, B. usteri, B. trimera, B. tridentata, B. uncinella by supercritical extraction in different conditions of operation, analyze them in different chromatographic methods and test its biological activities such as antioxidant and antimicrobial. As it shows high antioxidant potencial and high availability in the nature, the B. uncinella species were selected to continue our studies in order to perform the supercritical impregnation of the extract in sutures, one polymer matrix of PLGA. The antioxidant activity was the chosen characteristic to aggregate in the suture with the objective to enhance the healing were it is used. The results obtained shows that the impregnated material was not visualized through image analysis, but quantification and liberation tests as well as antioxidant activity shows that the impregnation has occurred. The impregnation condition at 150 bar showed superior results in relation to the impregnation at 200 bar, about 50% more mass impregnated and a 30% higher antioxidant activity. / O g?nero Baccharis possui mais de 500 esp?cies descritas sendo que 90% destas ocorrem na Am?rica do Sul. Possui importante destaque na medicina popular sendo utilizadas para problemas digestivos. Estudos reportam a presen?a de compostos fen?licos como flavonoides e ?cidos fen?licos em seus extratos n?o vol?teis. Extratos n?o vol?teis normalmente s?o obtidos por infus?o e/ou macera??o de partes de planta em solvente. Uma forma de obten??o de extratos puros sem necessidade de evapora??o do solvente ? a extra??o por fluido supercr?tico. O objetivo do presente estudo foi obter compostos n?o vol?teis de sete esp?cies de Baccharis: Baccharis microdonta, B. megapotamica, B. vulneraria, B. usteri, B. trimera, B. tridentata, B. uncinella por extra??o supercr?tica em diferentes condi??es de opera??o, analis?-los por diferentes m?todos cromatogr?ficos e testar suas atividades biol?gicas tais como atividade antioxidante e antimicrobiana. Por apresentar um potencial antioxidante elevado e grande disponibilidade na natureza, a esp?cie B. uncinella foi selecionada para dar continuidade aos estudos e realizar a impregna??o supercr?tica do extrato selecionado em fios de sutura, uma matriz polim?rica de PLGA. A atividade antioxidante foi a caracter?stica escolhida para agregar ao fio de sutura com o objetivo de potencializar a cicatriza??o do local onde for aplicado. Os resultados obtidos mostram que o material impregnado n?o foi visualizado atrav?s da an?lise de imagens, mas testes de quantifica??o e libera??o, assim como de atividade antioxidante, comprovaram que ocorre a impregna??o do extrato. A condi??o de impregna??o a 150 bar apresentou resultados superiores em rela??o a impregna??o a 200 bar, aproximadamente 50% mais massa impregnada e e uma atividade antioxidante 30% maior.

Orientador: Rubens Augusto Camargo Lamparelli / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Agricola / Made available in DSpace on 2018-08-13T09:46:25Z (GMT). No. of bitstreams: 1 Nery_LuisAntonio_M.pdf: 111375957 bytes, checksum: 05f2b3dc3fe0dece107d3e34a24a5a3e (MD5) Previous issue date: 2009 / Resumo: A importância econômica da produção brasileira de café no mercado mundial é notória e contribui com uma grande parcela na balança comercial de exportação do país. Minas Gerais se destaca como o centro da atual produção cafeeira no Brasil e tem na região sul do estado a grande concentração da lavoura de café (Coffea arabica), onde o seu cultivo é realizado em pequenas propriedades bastante dispersas pela região montanhosa. A necessidade de adequação da agricultura cafeeira por meio do planejamento, controle de custos e melhoria da produtividade, tem acelerado a procura por técnicas e ferramentas para a previsão da produção agrícola passando, necessariamente, pela localização e quantificação das áreas cultivadas. Neste contexto, o objetivo desta pesquisa foi avaliar o fornecimento de informações dos dados do sensor TM/Landsat 5 utilizando as técnicas de Análise por Principais Componentes (APC) e separação de classes de iluminação sobre as áreas de lavoura de café em região montanhosa. A área de estudo escolhida foi o município de Guaxupé/MG por conter uma forte lavoura cafeeira mantida sob um organizado sistema cooperativo. Foram utilizadas imagens dos satélites Landsat 7, Landsat 5 e do sensor MODIS para a aplicação das técnicas de processamento digital, para correção atmosférica e normalização radiométrica, visando a análise do cafeeiro nas datas de 15/08/2001, 05/12/2001 e 12/04/2002, que caracterizam os estágios fenológicos do cafeeiro como períodos de colheita (repouso e senescência dos ramos), florada e início do crescimento da gemas florais, respectivamente. Também foi utilizada uma máscara da área cafeeira obtida por método de interpretação visual extraído de imagens Ikonos. A utilização de um modelo digital de elevação gerado por imagens do sensor ASTER/TERRA possibilitou a aplicação da técnica de determinação do fator de iluminação, que consistiu na criação de classes de iluminação que contribuíram na identificação de áreas de lavoura e áreas de mata sombreadas pelo relevo. Dados de campo foram levantados para auxiliar na identificação da lavoura cafeeira, separadas pelas classes amostrais de café adensado e café adulto em função dos espaçamentos de ruas e linhas adotados no plantio. A Análise por Principais Componentes (APC) foi aplicada com o objetivo de reduzir a redundância dos dados obtidos das imagens orbitais de maneira a permitir a seleção de amostras de treinamento para a utilização em classificação supervisionada. Utilizando o método da Distância de Mahalanobis como classificador, as imagens nas datas selecionadas para a pesquisa, mostraram dados importantes quando comparados os resultados das classificações com a máscara da área de café extraída das imagens Ikonos do município. Os resultados dessas classificações foram validados por meio da determinação da Exatidão Global e coeficiente Kappa que mostraram os valores de EG= 0,78 e K= 0,40 para a imagem de 15/08/2001, EG= 0,81 e K= 0.29 para a imagem de 05/12/2001 e, EG= 0,76 e K= 0,24 para a data de 12/04/2002, confirmando que o período seco (maio até outubro) é favorável para a classificação do cafeeiro que, neste período está sob processo de colheita onde, a queda de folhas e remoção de frutos ocorre, diferenciando das outras coberturas do solo como as matas. Os maiores valores atingidos na validação dos dados ocorreram na classificação da imagem gerada pela composição dos resultados das três datas, atingindo valores de EG = 0,81 e Kappa = 0,56. O valor da área, quantificada como sendo da cultura do café, encontrado pelo método de soma dos resultados das classificações em cada data, produziu um valor 73,06 % do total de área quantificada na máscara de café, utilizada como referência. Neste sentido a metodologia se mostrou bem adequada na quantificação de áreas de café em relevo montanhoso. / Abstract: The economic importance of Brazilian coffee growing in the world market is notorious and makes up significant portion of the country's foreign trade exports. Minas Gerais stands out as the core of Brazilian coffee growing, with most of the planting areas (Coffea arabica) concentrated in the south, where it is grown in small plots widely spread throughout the hills. The need to adequate coffee agriculture by planning, cost control and productivity improvement has increased the search for techniques and tools for the prediction of agricultural production, necessarily involving the location and quantification of cultivated areas. In this context, the goal of this research has been to evaluate data from the TM/Landsat-5 remote sensor, providing information about coffee growing areas in hilly regions. The city of Guaxupé/MG/Brazil was chosen for this study due to its strong coffee growing, kept under an organized cooperate system. Images from the Landsat-7 and Landsat-5 satellites and from the MODIS sensor have been employed for the purpose of using digital processing tools for atmospheric correction and radiometric normalization, in order to analyze coffee crops in three dates: 08/15/2001, 12/05/2001 and 04/12/2002, characterizing phenological stages such as harvesting periods (rest and senescence of boughs), flowering and beginning of flower bud growing, respectively. The use of a digital elevation model generated from ASTER/TERRA sensor enabled the use of a lighting factor determination technique, consisting in the creation of lighting classes that contributed in the identification of crop areas and terrain-shadowed vegetated areas. Field data were gathered to help identifying coffee plantation separated by sample classes of dense coffee and adult coffee as a function of the spacing of the field foods and lines used in planting. PCA (Principal Component Analysis) was applied in order to reduce the redundancy of the data obtained from orbital imaging in a way that allows the selection of training samples for use in supervised classification. Using the Mahalanobis Distance as a classifier, the images in the selected dates showed highly positive result when the classification was compared to the coffee area mask extracted from Ikonos images. The results of these classifications were validated through the determination of Global Accuracy and Kappa Index, which showed values of GA= 0.78 and K= 0.40 for the 08/15/2001 image, GA= 0.81 and K= 0.29 for the 12/05/2001 image, and GA= 0.76 and K= 0.24 for 04/12/2002, confirming that the dry season (May through October) is favorable for the classification of coffee, which is under the harvesting process in this period, during which the falling of leaves and remotion of fruit separates it from other ground cover such as vegetation. The spectral data obtained from satellite imaging through digital processing have proven themselves adequate for the location of coffee-growing areas in hilly regions when aided by a digital elevation model. The value of the area as being coffee crop, calculated by sum of the areas found from each date classification, produced 73,06% of the agreement with coffee mask considered as a reference data. Due this the methodology showed very suitable to quantify coffee areas in hilly region. / Mestrado / Planejamento e Desenvolvimento Rural Sustentável / Mestre em Engenharia Agrícola

Presented diploma thesis was created in cooperation with Siemens s.r.o., and deals with the analysis of the bending of aluminium sheets which are later used as a conductors of high voltage electrical energy. These parts are completed into assemblies which serves as connectors of particular segments of an electrical network. The problem occurs as a result of incorrect bend, because it is impossible to join these sections properly. The customer would like to verify if the defined tolerances of semi-finished products are sufficient for proper bend and in case they are not, the tolerances should be modified. Due to the requirement for running numerical simulation in one of the open source software, the Salome-Meca program environment was used.

No description available.

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Οι δασικές πυρκαγιές αποτελούν αναπόσπαστο κομμάτι των Μεσογειακών οικοσυστημάτων επηρεάζοντας το φυσικό κύκλο διαδοχής της βλάστησης, αλλά και τη δομή και λειτουργία τους. Τα τελευταία χρόνια παρατηρείται αύξηση των δασικών πυρκαγιών αυξάνοντας ιδιαίτερα το επιστημονικό ενδιαφέρον. Η χρησιμοποίηση της δορυφορικής τηλεπισκόπησης στη χαρτογράφηση των καμένων εκτάσεων έχει τριάντα χρόνια ιστορία ως εργαλείο χαρτογράφησης αλλά και παρακολούθησης της εξέλιξης των καμένων εκτάσεων. Η χαρτογράφηση των δασικών πυρκαγιών με τη χρήση δορυφορικών δεδομένων είναι και σήμερα ένα εν ενεργεία αντικείμενο έρευνας της τηλεπισκόπησης. Πολλά χαρακτηριστικά παραδείγματα υπάρχουν στη διεθνή βιβλιογραφία με ερευνητικό αντικείμενο τη χαρτογράφηση των καμένων εκτάσεων με τη χρήση πολλαπλών τύπων δορυφορικών δεδομένων, όμως ο αριθμός αυτών που διαπραγματεύονται για την ίδια πυρκαγιά πολλούς τύπους δεδομένων είναι περιορισμένος. Στην παρούσα διδακτορική διατριβή επιχειρείται για πρώτη φορά η χαρτογράφηση των καμένων εκτάσεων με εκτεταμένη χρήση διαφόρων τύπων δορυφορικών εικόνων πολλαπλής φασματικής και χωρικής διακριτικής ικανότητας που έχουν αποκτηθεί για την ίδια πυρκαγιά (Πάρνηθα, 2007). Πιο συγκεκριμένα, αντικείμενο έρευνας αποτέλεσε η χαρτογράφηση των άκαυτων νησίδων εσωτερικά της περιμέτρου της πυρκαγιάς, καθώς και η διερεύνηση των παραγόντων που διαμορφώνουν την ακρίβεια της χαρτογράφησης, η διερεύνηση της ευαισθησίας των τιμών ανάκλασης σε διαφορετικές αναλογίες καμένου/βλάστησης, καθώς και η εφαρμογή και αξιολόγηση διαφόρων δεικτών βλάστησης. Τα δορυφορικά δεδομένα που αξιολογήθηκαν προέρχονται από τους δορυφορικούς ανιχνευτές IKONOS, LANDSAT, ASTER και MODIS. Παράλληλα με τα αρχικά δεδομένα δημιουργήθηκε ένα σύνολο εικόνων πολλαπλής φασματικής και χωρικής κλίμακας. Αρχικά, εφαρμόστηκαν κλασικοί αλγόριθμοι επεξεργασίας εικόνας για τη γεωμετρική, ραδιομετρική και ατμοσφαιρική διόρθωση των δορυφορικών εικόνων. Στη συνεχεία, επεξεργάστηκε η υψηλής ανάλυσης εικόνα IKONOS, η οποία αποτέλεσε τη βάση για τον υπολογισμό του ποσοστού κάλυψης των καμένων εκτάσεων, της βλάστησης και του γυμνού εδάφους σε επίπεδο εικονοστοιχείου. Λαμβάνοντας υπόψη διαφορετικούς συνδυασμούς φασματικών και χωρικών αναλύσεων πραγματοποιήθηκαν συνολικά 420 ταξινομήσεις. Επιπλέον, οι φασματικοί δίαυλοι καθώς και 57 δείκτες βλάστησης που υπολογίστηκαν, συσχετίστηκαν με περιοχές διαφορετικών αναλογιών καμένης και άκαυτης βλάστησης, με σκοπό τη διερεύνηση της ευαισθησίας τους στην εκτίμηση του ποσοστού των καμένων και μη καμένων περιοχών. Συμπερασματικά, η χωρική διακριτική ικανότητα αποδεικνύεται ως ο σημαντικότερος παράγοντας για την αποτύπωση των άκαυτων νησίδων εσωτερικά της περιμέτρου της πυρκαγιάς, ενώ διαπιστώθηκε ότι συσχετίζεται άμεσα με τον αριθμό των χαρτογραφημένων νησίδων. Επιπλέον, το κοντινό και μέσο υπέρυθρο τμήμα του φάσματος αποδείχτηκαν σημαντικά για την εκτίμηση του ποσοστού του καμένου, ενώ το κόκκινο και κοντινό υπέρυθρο για την εκτίμηση του ποσοστού της βλάστησης. Το τελευταίο φαίνεται ότι διαδραματίζει σημαντικό ρόλο στον υπολογισμό του ποσοστού των καμένων εκτάσεων, ενώ το μέσο υπέρυθρο στον υπολογισμό του ποσοστού της βλάστησης. Οι δείκτες βλάστησης ελαχιστοποιούν τις επιδράσεις εξωτερικών παραγόντων, όπως είναι η επίδραση του εδάφους. Έτσι, οι ενδιάμεσες κατηγορίες κρίθηκαν πιο σύμφωνες φασματικά με τις διαφορετικές αναλογίες καμένου/βλάστησης, σε σχέση με τους αρχικούς φασματικούς δίαυλους, βάσει των οποίων υπολογίζονται οι δείκτες. Οι κλασικοί δείκτες, οι οποίοι ενσωματώνουν το κόκκινο και κοντινό υπέρυθρο μήκος κύματος έδειξαν καλύτερη προσαρμογή στην εκτίμηση του ποσοστού της βλάστησης. Αντίθετα, η τροποποιημένη εκδοχή τους, αντικαθιστώντας το κόκκινο με το μέσο υπέρυθρο τμήμα του φάσματος έδειξαν καλύτερη προσαρμογή στην εκτίμηση του ποσοστού των καμένων περιοχών, ταυτόχρονα με την υψηλή προσαρμογή για την εκτίμηση της βλάστησης. Τέλος, πραγματοποιήθηκε η ανασύσταση της πρόσφατης ιστορίας των πυρκαγιών (1984-2011) για την Αττική, εφαρμόζοντας πρόσφατα ανεπτυγμένες (ημι)αυτόματες τεχνικές χαρτογράφησης σε διαχρονικά LANDSAT δορυφορικά δεδομένα μεσαίας χωρικής διακριτικής ικανότητας. Τα αποτελέσματα αυτής της διαδικασίας οδήγησαν στη χαρτογράφηση των περιμέτρων των πυρκαγιών με σχετικά μεγάλη ακρίβεια, ενώ από τα μοντέλα παλινδρόμησης διαπιστώθηκε ότι οι διαφορές μεταξύ της καμένης έκτασης που υπολογίζεται από τα δορυφορικά δεδομένα και αυτά τα οποία καταγράφονται από τη Δασική Υπηρεσία αποδίδονται στον αριθμό των δορυφορικών εικόνων που χρησιμοποιούνται καθώς και στην ημερομηνία απόκτησης της πρώτης δορυφορικής εικόνας. / Forest fires, an integral part of Mediterranean ecosystems, affect the natural cycle of vegetation succession and the ecosystem’s structure and function. Recently, the increment in frequency of fires has increased the concern of the scientific community. The use of remote sensing in burned land mapping has a 30 year long history as tool in mapping and monitoring of forest fire. Despite this long period, burned land mapping using satellite data is still an active research topic in satellite remote sensing. Many characteristic examples of satellite remote sensing studies of burned land mapping and monitoring can be found in the literature, however studies dealing with a multisource data set for the same fire event are limited. The present thesis attempted to map burned surfaces using a multisource satellite data set of multiple spectral and spatial resolution acquired for the same fire event (Parnitha, 2007). In particular, the aims of the thesis were to delineate the unburned patches within fire scar perimeter and explore the factors influence the classification accuracy, to explore the sensitivity of spectral reflectance values to different burn and vegetation ratios, as well as to examine and evaluate some vegetation indices. The satellite data used were acquired from IKONOS, LANDSAT, ASTER and MODIS. Along with the basic data set, a spatially degraded satellite data over a range of coarser resolutions were created. Firstly, classical image processing algorithms were applied to correct geometrically, radiometrically and atmospherically the satellite images used. The pan-sharpened IKONOS served as the basis to estimate the percent of cover of burned areas, vegetation and bare land, at pixel level. Totally 420 classifications have been implemented considering different combinations of spectral and spatial resolutions. Additionally, the spectral bands and 57 versions of some classical vegetation indices were correlated with different burned and vegetation ratios in order to explore their sensitivity. Conclusively, spatial resolution is the most important factor for the delineation of the unburned patches within the fire scar perimeter, while proved to be strongly correlated with the number of the mapped islands. Moreover, the near and middle infrared channels were the most important ones to estimate the percentage of burned area, while the red and near infrared were the most important channels to estimate the percentage of vegetation. The latter, seemed to play a more significant role in estimating the percent of burned area while the middle infrared seemed to play a more significant role in estimating the percent of vegetation. Vegetation indices are less sensitive to external parameters of the vegetation by minimizing external effects, such as soil impact. Thus, the semi-burned classes were spectrally more consistent to their different fractions of scorched and non-scorched vegetation, than the original spectral channels based on which these indices are estimated. The classical indices, which incorporate the red-near infrared space showed better performance to estimate the percent of the vegetation. In contrast, the modified version of the classical indices, by replacing the red with the middle infrared channel showed the highest performance to estimate the percent of burned areas, apart from the high performance in the estimation of the vegetation. Finally, in the present thesis maps with the reconstruction of the recent fire history of Attica region were created, in a spatially explicit mode using (semi)automated image processing techniques in a series of multi-temporal medium-resolution LANDSAT images. The results showed that the fire-scar perimeters were captured with considerably high accuracy, while regression modeling showed that the differences between the area burned estimated from satellite data and that recorded by the forest service can be explained by the number of satellite images used followed by the acquisition date of the first image.

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