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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.
41

Erosão hídrica influenciada pelo uso da terra e manejo do solo / Water erosion influenced by land use and management of soil

Souza, Vinicius Ferreira Chaves de 23 June 2016 (has links)
Submitted by Claudia Rocha (claudia.rocha@udesc.br) on 2018-03-07T13:14:32Z No. of bitstreams: 1 PGCS16MA147.pdf: 1188975 bytes, checksum: 7fb2079dde5dc53eb4de7d465ebc2539 (MD5) / Made available in DSpace on 2018-03-07T13:14:32Z (GMT). No. of bitstreams: 1 PGCS16MA147.pdf: 1188975 bytes, checksum: 7fb2079dde5dc53eb4de7d465ebc2539 (MD5) Previous issue date: 2016-06-23 / Water erosion is the main soil degradation factor, which is influenced by rain, soil, relief, land use and management and coverage and conservation practices. The land use, coverage and soil management is not always adequate, resulting in significant erosion due also to the lack of cultivation and conservation practices adapted systems. As a result, the water and soil loss by water erosion were quantified in Haplumbrept soil in two experiments. In one, the treatments without replicate were differentiated by doses of fertilizer applied to the soil surface in no-tillage condition. In another experiment, with a replicate, the treatments consisted of no-tillage, burned natural pasture and native pasture. In no-tillage treatments were cultivated radish, black beans, vetch, corn, oats and soybeans in rotation. Treatments with crops, with natural pasture and burned natural pasture were compared to a control treatment where the soil was kept uncultivated and unfertilized. Increases fertilizer dose applied on the soil surface cultivated by direct seeding condition increased the production of plant biomass and grain and reduced water loss and soil erosion by water. Increases fertilizer dose applied on the soil surface cultivated by direct seeding condition increased the phosphorus content in the soil surface and, thus, increased the content of the erosion sediments, but decreased the total amount of the element lost by water erosion. The loss of soil and water erosion by water related exponentially decreasing manner with the amount of fertilizer applied on the soil surface in no-tillage condition. The loss of soil by erosion is changed with the change of land use; It were lower in the native field condition, intermediate in native pasture submitted to the annual and largest growing native field in which the aerial biomass is regularly burned; water losses are not modified. The water losses by runoff are less influenced than soil loss by water erosion, both in different conditions of soil management, as in different forms of land use / A erosão hídrica é o principal fator de degradação do solo, a qual é influenciada pela chuva, solo, relevo, uso da terra e manejo e cobertura e práticas de conservação. O uso da terra, a cobertura e manejo do solo nem sempre é adequado, o que resulta em grande erosão, devido, ainda, à falta de sistemas de cultivo e de práticas conservacionistas adaptadas. Em função disso, as perdas de água e solo pela erosão hídrica foram quantificadas num Cambissolo Húmico alumínico léptico, em dois experimentos. Em um, os tratamentos, sem repetição, foram diferenciados por doses de adubo aplicado na superfície do solo em condição de semeadura direta. Em outro experimento, com uma repetição, os tratamentos consistiram de semeadura direta, campo nativo queimado e campo nativo. Nos tratamentos de semeadura direta foram cultivados nabo forrageiro, feijão preto, ervilhaca comum, milho, aveia preta e soja, em rotação. Os tratamentos com cultivo e os de campo foram comparados a um tratamento testemunha em que o solo foi mantido sem cultivo e sem adubação. O aumento da dose de adubos aplicados na superfície do solo cultivado em condição de semeadura direta aumentou a produção de biomassa vegetal e de grãos e diminui as perdas de água e solo por erosão hídrica. O aumento da dose de adubos aplicados na superfície do solo cultivado em condição de semeadura direta aumentou o teor de fósforo na superfície do solo e, com isso, aumenta o teor nos sedimentos da erosão, mas diminuiu a quantidade total do elemento perdido por erosão hídrica. As perdas de solo e de água por erosão hídrica se relacionaram exponencialmente, de modo decrescente, com a quantidade de adubos aplicados na superfície do solo em condição de semeadura direta. A perda de solo por erosão hídrica foi modificada com a mudança de uso da terra; foi menor na condição de campo nativo, intermediária em campo nativo submetido ao cultivo anual e maior em campo nativo em que a biomassa da parte aérea é regularmente queimada; as perdas de água não foram modificadas. As perdas de água por escoamento superficial foram menos influenciadas do que as perdas de solo por erosão hídrica, tanto em diferentes condições de manejo do solo, quanto, em distintas formas de uso da terra
42

O Índice de Haines como indicador de desenvolvimento de focos de calor no Brasil através do modelo “Eta”

Lemos, Carlos Fernando 23 March 2016 (has links)
Submitted by Biblioteca de Pós-Graduação em Geoquímica BGQ (bgq@ndc.uff.br) on 2016-03-23T17:52:26Z No. of bitstreams: 1 TESE CARLOS FERNANDO LEMOS COMPLETO PDF (2).pdf: 11612325 bytes, checksum: 67b79cc3654416003380c8d20e2b911f (MD5) / Made available in DSpace on 2016-03-23T17:52:26Z (GMT). No. of bitstreams: 1 TESE CARLOS FERNANDO LEMOS COMPLETO PDF (2).pdf: 11612325 bytes, checksum: 67b79cc3654416003380c8d20e2b911f (MD5) / Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro / Universidade Federal Fluminense. Instituto de Química. Programa de Pós-Graduação em Geociências-Geoquímica. Niterói, RJ / Através do modelo de área limitada Eta, que foi desenvolvido pela Universidade de Belgrado em conjunto com o Instituto de Hidrometeorologia da Iugoslávia, aplicou-se a este modelo o Índice de Haines que é especialmente um índice de estabilidade atmosférica desenvolvido para uso previsão de desenvolvimento de queimadas. Este índice é determinado combinando a estabilidade atmosférica e a umidade do ar de níveis pré-determinados da atmosfera resultando em valores de propagação de fogo. Para estabelecer e discutir sobre as queimadas no Brasil, é necessário saber as condições atmosféricas favoráveis para que ocorra este fenômeno. Assim foram feitas análises dinâmicas e sinóticas de grande escala sobre a América do Sul e do Brasil. Foram observadas imagens de satélite e também foram coletados dados de normais climatológicas para obter-se uma visão geral do escoamento da atmosfera, direção dos ventos, sistemas sinóticos dominantes e os fenômenos atmosféricos que influenciam o tempo, clima e microclima de cada região do Brasil. Para tal, foram gerados mapas do Índice de Haines durante os anos de 2003 e 2004, reanálise e gráficos comparativos matriciais entre os focos de calor com as imagens de satélite NOAA-12, para verificar a validade deste índice para o Brasil. O Índice de Haines é usado em vários países como o Canadá, Estados Unidos, Austrália, países da União Européia e no Sudeste Asiático. O número de focos de incêndios cresce a cada ano, assim este estudo visa estabelecer mais uma ferramenta para as medidas de prevenção e de controle dos focos de calor no Brasil / Through the model of limited area Eta, that was developed by the University of Belgrade together with the Institute of Hidrometeorology of Yugoslavia, was applied to this model the Index of Haines that is especially an index of Atmospheric stability developed for use forecast of development of burning. This index is determined combining the atmospheric stability and of the humidity of the air in the lowest level of the atmosphere resulting in values of fire propagation for other levels of the atmosphere. To establish and to discuss on the burning in Brazil, it was necessary to know the favorable atmospheric conditions so that it happens this phenomenon, they were made like this dynamic analyses and sinotics of great scale on South America and of Brazil, satellite images were observed and also data of climatological normal were collected, to obtain a general vision of the drainage of the atmosphere, direction of the winds, systems dominant sinotics and the atmospheric phenomena that influence the weather, climate and microclimatic of each area of Brazil. Maps of the Index of Haines were generated during the years of 2003 and 2004, reanalisys and graphs comparative matrix among the burning with the satellite images NOAA-12, to verify the validity of this index to Brazil. The Index of Haines is used at several countries as Canada, United States, Australia, countries of the European Union and in the Asian Southeast. The number of focuses of fires grows every year. This study seeks to establish one more tool for the prevention measures and of control of the focuses of heat in Brazil
43

De quelques livres brûlés : la représentation d'autodafés de livres au Siècle des Lumières

Leduc, Diane 08 1900 (has links)
Ce mémoire étudie les autodafés de livres représentés dans trois textes français de la seconde moitié du XVIIIe siècle : l’article « Bibliomanie » (1752) de l’Encyclopédie, écrit par Jean le Rond D’Alembert, le roman l’An deux mille quatre cent quarante. Rêve s’il en fut jamais (1770) de Louis Sébastien Mercier et la comédie le Bureau d’esprit (1776-1777) de Jean-Jacques Rutlidge. Il révèle, chez ces auteurs, une critique du livre qui paradoxalement s’accompagne de sa défense. Le premier chapitre décrit succinctement la croissance de l’imprimé en France, à l’époque, l’évolution des goûts en matière de lecture, et un imaginaire du livre dans lequel entrent une impression d’envahissement et une grande admiration pour l’écrit. Les trois chapitres subséquents suivent l’ordre chronologique de parution des textes retenus et analysent les scènes de livres brûlés qu’ils contiennent. D’Alembert et Mercier, non sans réserves, aimeraient jeter au feu la majorité des livres qui les entourent. Rutlidge constitue un cas particulier : l’autodafé vise un ouvrage précis, soit une traduction française de Shakespeare. Le mémoire, en conclusion, évoque quatre textes plus récents où sont rapportés des autodafés de livres : le poème « À qui la faute ? » de Victor Hugo, le roman Fahrenheit 451 de Ray Bradbury, la pièce les Combustibles d’Amélie Nothomb et le roman les Corpuscules de Krause de Sandra Gordon. Reprenant des idées présentes chez D’Alembert, Mercier et Rutlidge, ces œuvres illustrent leur richesse. / This thesis studies the burning of books as depicted in three French texts from the second half of the 18th century : the article “ Bibliomanie ” (1752) from the Encyclopédie, written by Jean le Rond D’Alembert, the novel l’An deux mille quatre cent quarante. Rêve s’il en fut jamais (1770) by Louis Sébastien Mercier, and the comedy le Bureau d’esprit by Jean-Jacques Rutlidge (1776-1777). These authors criticize books, but paradoxically defend their value. The first chapter is a succinct description of the growth of printed matter in France and of the changing tastes in reading. There is then a sense of being overwhelmed by the sheer volume of material, but at the same time a real admiration for writing itself. The next three chapters discuss the texts in chronological order, paying particular attention to the passages where books are burned. D’Alembert and Mercier, with some ambivalence, would like to commit to the flames most of the books which surround them. Rutlidge shows the ritual sacrifice of one work, a contemporary French translation of Shakespeare. In conclusion this thesis briefly considers four more recent texts dealing with the destruction of books : the poem “ À qui la faute ? ” by Victor Hugo, the novel Fahrenheit 451 by Ray Bradbury, the play les Combustibles by Amélie Nothomb, and the novel les Corpuscules de Krause by Sandra Gordon. These works develop ideas seen in D’Alembert, Mercier and Rutlidge, showing their worthiness.
44

De quelques livres brûlés : la représentation d'autodafés de livres au Siècle des Lumières

Leduc, Diane 08 1900 (has links)
Ce mémoire étudie les autodafés de livres représentés dans trois textes français de la seconde moitié du XVIIIe siècle : l’article « Bibliomanie » (1752) de l’Encyclopédie, écrit par Jean le Rond D’Alembert, le roman l’An deux mille quatre cent quarante. Rêve s’il en fut jamais (1770) de Louis Sébastien Mercier et la comédie le Bureau d’esprit (1776-1777) de Jean-Jacques Rutlidge. Il révèle, chez ces auteurs, une critique du livre qui paradoxalement s’accompagne de sa défense. Le premier chapitre décrit succinctement la croissance de l’imprimé en France, à l’époque, l’évolution des goûts en matière de lecture, et un imaginaire du livre dans lequel entrent une impression d’envahissement et une grande admiration pour l’écrit. Les trois chapitres subséquents suivent l’ordre chronologique de parution des textes retenus et analysent les scènes de livres brûlés qu’ils contiennent. D’Alembert et Mercier, non sans réserves, aimeraient jeter au feu la majorité des livres qui les entourent. Rutlidge constitue un cas particulier : l’autodafé vise un ouvrage précis, soit une traduction française de Shakespeare. Le mémoire, en conclusion, évoque quatre textes plus récents où sont rapportés des autodafés de livres : le poème « À qui la faute ? » de Victor Hugo, le roman Fahrenheit 451 de Ray Bradbury, la pièce les Combustibles d’Amélie Nothomb et le roman les Corpuscules de Krause de Sandra Gordon. Reprenant des idées présentes chez D’Alembert, Mercier et Rutlidge, ces œuvres illustrent leur richesse. / This thesis studies the burning of books as depicted in three French texts from the second half of the 18th century : the article “ Bibliomanie ” (1752) from the Encyclopédie, written by Jean le Rond D’Alembert, the novel l’An deux mille quatre cent quarante. Rêve s’il en fut jamais (1770) by Louis Sébastien Mercier, and the comedy le Bureau d’esprit by Jean-Jacques Rutlidge (1776-1777). These authors criticize books, but paradoxically defend their value. The first chapter is a succinct description of the growth of printed matter in France and of the changing tastes in reading. There is then a sense of being overwhelmed by the sheer volume of material, but at the same time a real admiration for writing itself. The next three chapters discuss the texts in chronological order, paying particular attention to the passages where books are burned. D’Alembert and Mercier, with some ambivalence, would like to commit to the flames most of the books which surround them. Rutlidge shows the ritual sacrifice of one work, a contemporary French translation of Shakespeare. In conclusion this thesis briefly considers four more recent texts dealing with the destruction of books : the poem “ À qui la faute ? ” by Victor Hugo, the novel Fahrenheit 451 by Ray Bradbury, the play les Combustibles by Amélie Nothomb, and the novel les Corpuscules de Krause by Sandra Gordon. These works develop ideas seen in D’Alembert, Mercier and Rutlidge, showing their worthiness.
45

Vliv volejbalu na zdravotní stav hráčů / Health Effects of volleyball players

Hrbáčková, Markéta January 2021 (has links)
Title: The influence of volleyball on sports and after sports life of players Objectives: The aim of this work is to find out in a comprehensive way the extent to which players are affected by long-term performance in an active volleyball team, how it affects the psychosomatic state of players and the possible impact of the game on the life of the player even after their sports career. Methods: The thesis uses many-case exploratory studies with data collection through structured questionnaire forms and supplementary interviews. A total of 60 respondents participated in this qualitative research. The obtained data was examined by using the thematic analysis method. Tables and accompanying reports were used as an output form, formulating the researched phenomena and connecting the research with the theoretical part of the work. Results: The collected data emphasized the importance of respecting the personalities of the players in all aspects. They confirmed the importance of harmony between the physical and mental aspects of the approach to training and game, and thus emphasized the psychosomatic unity that must be respected by the coach if the goal is a top notch game of the team as a whole. The research further confirmed that the background of the players lies not only in the broader social context...
46

Contribution à la validation d’un outil informatique pour l’évaluation des surfaces corporelles brûlées

Matei, Svetlana 08 1900 (has links)
INTRODUCTION L’évaluation de la surface corporelle brûlée, essentielle pour établir la réanimation volémique et statuer sur le pronostic, se base actuellement sur la transposition des brûlures observées sur des diagrammes en papier représentant des mannequins standard. Le but de ce projet est de contribuer à la validation d’un outil pour l’évaluation des ratios brûlés. Deux outils ont été proposés, un numériseur portable et les mesures anthropométriques. MÉTHODES Quatre mannequins commerciaux avec différentes morphologies ont été sélectionnés. Chaque mannequin a été numérisé 10 fois avec un numériseur portable et une fois avec un numériseur de référence. Les surfaces corporelles totales ont été calculées et comparées. Dans un deuxième temps, 14 volontaires ont estimé la surface coporelle brûlée en utilisant les diagrammes papier et en dessinant sur un logiciel. RÉSULTATS Les valeurs des surfaces corporelles totales obtenues avec le numériseur portable sont 0,812; 1,581; 1,711 et 1,916 m2 pour les mannequins enfant, femme I, femme II et homme. Les résultats du numériseur de référence sont 0,815; 1,588; 1,716 et 1,918 m2. Les ratios des surfaces brûlées des mannequins correspondent à 23,33; 22,67, 32,63 et 26,07 % pour les mannequins. Les estimations des surfaces brûlées obtenues avec les diagrammes en papier représentent 29,9; 32,5; 40,4 et 35,7 %. Les résultats obtenus avec le logiciel sont 23,5; 22,6; 32,1 et 25,1 %. CONCLUSION Le numériseur portable reproduit avec précision et exactitude la surface corporelle totale. L’utilisation des données anthropométriques pour le calcul du pourcentage brûlé représente un outil plus précis et exact que les diagrammes papier. / PURPOSE Total body surface area burned assessment is currently based on the transpositon of burns seen on paper charts representing standard models. The purpose of this project is to contribute to the validation of a tool for TBSA assessment. A handheld 3D scanner and anthropometrical measurements have been proposed. METHODS Four commercial mannequins with different body shapes were selected. Each model was scanned 10 times with a handhed, white light scanner and once with a gold standard scanner. The images were transferred to a modelling software allowing to assess the total body surface. Total body surfaces were calculated and compared. Secondly, 14 volunteers estimated the total burned surface using paper charts and drawing on 3D virtual models. RESULTS Values of the total body surface obtained with the handheld scanner are 0.812; 1.581; 1.711 and 1.916 m2 for the child, female I, female II and male mannequins. The results of the gold standard scanner are 0.815 ; 1.588 ; 1.716 and 1.918 m2. Burn extent ratios correspond to 23.33 ; 22.67 ; 32.63 and 26.07 % for the same mannequins. Estimated burned surfaces obtained with paper diagrams are the following : 29.9 ; 32.5 ; 40.4 and 35.7 %. Results obtained with the software are 23.5 ; 22.6 ; 32.1 and 25.1 %. CONCLUSION The handheld scanner is a precise and accurate tool for the assessment of the total surface. Use of anthropometric data for the calculation of the body burned surface is a more accurate tool and less variable than the conventional paper charts.
47

PREDICTION OF PREMIXED INTERNAL COMBUSTION ENGINE MASS FRACTON BURNED PROFILES USING A PHYSICAL FORM OF THE WIEBE FUNCTION AND THE THEORY OF TURBULENT FLAME BRUSH THICKNESS DYNAMICS

Aquino, Phillip A. January 2020 (has links)
No description available.
48

Multispectral Remote Sensing and Deep Learning for Wildfire Detection / Multispektral fjärranalys och djupinlärning för upptäckt av skogsbränder

Hu, Xikun January 2021 (has links)
Remote sensing data has great potential for wildfire detection and monitoring with enhanced spatial resolution and temporal coverage. Earth Observation satellites have been employed to systematically monitor fire activity over large regions in two ways: (i) to detect the location of actively burning spots (during the fire event), and (ii) to map the spatial extent of the burned scars (during or after the event). Active fire detection plays an important role in wildfire early warning systems. The open-access of Sentinel-2 multispectral data at 20-m resolution offers an opportunity to evaluate its complementary role to the coarse indication in the hotspots provided by MODIS-like polar-orbiting and GOES-like geostationary systems. In addition, accurate and timely mapping of burned areas is needed for damage assessment. Recent advances in deep learning (DL) provides the researcher with automatic, accurate, and bias-free large-scale mapping options for burned area mapping using uni-temporal multispectral imagery. Therefore, the objective of this thesis is to evaluate multispectral remote sensing data (in particular Sentinel-2) for wildfire detection, including active fire detection using a multi-criteria approach and burned area detection using DL models.        For active fire detection, a multi-criteria approach based on the reflectance of B4, B11, and B12 of Sentinel-2 MSI data is developed for several representative fire-prone biomes to extract unambiguous active fire pixels. The adaptive thresholds for each biome are statistically determined from 11 million Sentinel-2 observations samples acquired over summertime (June 2019 to September 2019) across 14 regions or countries. The primary criterion is derived from 3 sigma prediction interval of OLS regression of observation samples for each biome. More specific criteria based on B11 and B12 are further introduced to reduce the omission errors (OE) and commission errors (CE).        The multi-criteria approach proves to be effective in cool smoldering fire detection in study areas with tropical &amp; subtropical grasslands, savannas &amp; shrublands using the primary criterion. At the same time, additional criteria that thresholds the reflectance of B11 and B12 can effectively decrease the CE caused by extremely bright flames around the hot cores in testing sites with Mediterranean forests, woodlands &amp; scrub. The other criterion based on reflectance ratio between B12 and B11 also avoids the effects of CE caused by hot soil pixels in sites with tropical &amp; subtropical moist broadleaf forests. Overall, the validation performance over testing patches reveals that CE and OE can be kept at a low level  (0.14 and 0.04) as an acceptable trade-off. This multi-criteria algorithm is suitable for rapid active fire detection based on uni-temporal imagery without the requirement of multi-temporal data. Medium-resolution multispectral data can be used as a complementary choice to the coarse resolution images for their ability to detect small burning areas and to detect active fires more accurately.        For burned area mapping, this thesis aims to expound on the capability of deep DL models for automatically mapping burned areas from uni-temporal multispectral imagery. Various burned area detection algorithms have been developed using Sentinel-2 and/or Landsat data, but most of the studies require a pre-fire image, dense time-series data, or an empirical threshold. In this thesis, several semantic segmentation network architectures, i.e., U-Net, HRNet, Fast- SCNN, and DeepLabv3+ are applied to Sentinel-2 imagery and Landsat-8 imagery over three testing sites in two local climate zones. In addition, three popular machine learning (ML) algorithms (LightGBM, KNN, and random forests) and NBR thresholding techniques (empirical and OTSU-based) are used in the same study areas for comparison.        The validation results show that DL algorithms outperform the machine learning (ML) methods in two of the three cases with the compact burned scars,  while ML methods seem to be more suitable for mapping dispersed scar in boreal forests. Using Sentinel-2 images, U-Net and HRNet exhibit comparatively identical performance with higher kappa (around 0.9) in one heterogeneous Mediterranean fire site in Greece; Fast-SCNN performs better than others with kappa over 0.79 in one compact boreal forest fire with various burn severity in Sweden. Furthermore, directly transferring the trained models to corresponding Landsat-8 data, HRNet dominates in the three test sites among DL models and can preserve the high accuracy. The results demonstrate that DL models can make full use of contextual information and capture spatial details in multiple scales from fire-sensitive spectral bands to map burned areas. With the uni-temporal image, DL-based methods have the potential to be used for the next Earth observation satellite with onboard data processing and limited storage for previous scenes.    In the future study, DL models will be explored to detect active fire from multi-resolution remote sensing data. The existing problem of unbalanced labeled data can be resolved via advanced DL architecture, the suitable configuration on the training dataset, and improved loss function. To further explore the damage caused by wildfire, future work will focus on the burn severity assessment based on DL models through multi-class semantic segmentation. In addition, the translation between optical and SAR imagery based on Generative Adversarial Network (GAN) model could be explored to improve burned area mapping in different weather conditions. / Fjärranalysdata har stor potential för upptäckt och övervakning av skogsbränder med förbättrad rumslig upplösning och tidsmässig täckning. Jordobservationssatelliter har använts för att systematiskt övervaka brandaktivitet över stora regioner på två sätt: (i) för att upptäcka placeringen av aktivt brinnande fläckar (under brandhändelsen) och (ii) för att kartlägga den brända ärrens rumsliga omfattning ( under eller efter evenemanget). Aktiv branddetektering spelar en viktig roll i system för tidig varning för skogsbränder. Den öppna tillgången till Sentinel-2 multispektral data vid 20 m upplösning ger en möjlighet att utvärdera dess kompletterande roll i förhållande till den grova indikationen i hotspots som tillhandahålls av MODIS-liknande polaromloppsbanesystem och GOES-liknande geostationära system. Dessutom krävs en korrekt och snabb kartläggning av brända områden för skadebedömning. Senaste framstegen inom deep learning (DL) ger forskaren automatiska, exakta och förspänningsfria storskaliga kartläggningsalternativ för kartläggning av bränt område med unitemporal multispektral bild. Därför är syftet med denna avhandling att utvärdera multispektral fjärranalysdata (särskilt Sentinel- 2) för att upptäcka skogsbränder, inklusive aktiv branddetektering med hjälp av ett multikriterietillvägagångssätt och detektering av bränt område med DL-modeller. För aktiv branddetektering utvecklas en multikriteriemetod baserad på reflektionen av B4, B11 och B12 i Stentinel-2 MSI data för flera representativa brandbenägna biom för att få fram otvetydiga pixlar för aktiv brand. De adaptiva tröskelvärdena för varje biom bestäms statistiskt från 11 miljoner Sentinel-2 observationsprover som förvärvats under sommaren (juni 2019 till september 2019) i 14 regioner eller länder. Det primära kriteriet härleds från 3-sigma-prediktionsintervallet för OLS-regression av observationsprover för varje biom. Mer specifika kriterier baserade på B11 och B12 införs vidare för att minska utelämningsfel (OE) och kommissionsfel (CE). Det multikriteriella tillvägagångssättet visar sig vara effektivt när det gäller upptäckt av svala pyrande bränder i undersökningsområden med tropiska och subtropiska gräsmarker, savanner och buskmarker med hjälp av det primära kriteriet. Samtidigt kan ytterligare kriterier som tröskelvärden för reflektionen av B11 och B12 effektivt minska det fel som orsakas av extremt ljusa lågor runt de heta kärnorna i testområden med skogar, skogsmarker och buskage i Medelhavsområdet. Det andra kriteriet som bygger på förhållandet mellan B12 och B11:s reflektionsgrad undviker också effekterna av CE som orsakas av heta markpixlar i områden med tropiska och subtropiska fuktiga lövskogar. Sammantaget visar valideringsresultatet för testområden att CE och OE kan hållas på en låg nivå (0,14 och 0,04) som en godtagbar kompromiss. Algoritmen med flera kriterier lämpar sig för snabb aktiv branddetektering baserad på unika tidsmässiga bilder utan krav på tidsmässiga data. Multispektrala data med medelhög upplösning kan användas som ett kompletterande val till bilder med kursupplösning på grund av deras förmåga att upptäcka små brinnande områden och att upptäcka aktiva bränder mer exakt. När det gäller kartläggning av brända områden syftar denna avhandling till att förklara hur djupa DL-modeller kan användas för att automatiskt kartlägga brända områden från multispektrala bilder i ett tidsintervall. Olika algoritmer för upptäckt av brända områden har utvecklats med hjälp av Sentinel-2 och/eller Landsat-data, men de flesta av studierna kräver att man har en förebränning. bild före branden, täta tidsseriedata eller ett empiriskt tröskelvärde. I den här avhandlingen tillämpas flera arkitekturer för semantiska segmenteringsnätverk, dvs. U-Net, HRNet, Fast- SCNN och DeepLabv3+, på Sentinel- 2 bilder och Landsat-8 bilder över tre testplatser i två lokala klimatzoner. Dessutom används tre populära algoritmer för maskininlärning (ML) (Light- GBM, KNN och slumpmässiga skogar) och NBR-tröskelvärden (empiriska och OTSU-baserade) i samma undersökningsområden för jämförelse. Valideringsresultaten visar att DL-algoritmerna överträffar maskininlärningsmetoderna (ML) i två av de tre fallen med kompakta brända ärr, medan ML-metoderna verkar vara mer lämpliga för kartläggning av spridda ärr i boreala skogar. Med hjälp av Sentinel-2 bilder uppvisar U-Net och HRNet jämförelsevis identiska prestanda med högre kappa (omkring 0,9) i en heterogen brandplats i Medelhavet i Grekland; Fast-SCNN presterar bättre än andra med kappa över 0,79 i en kompakt boreal skogsbrand med varierande brännskadegrad i Sverige. Vid direkt överföring av de tränade modellerna till motsvarande Landsat-8-data dominerar HRNet dessutom på de tre testplatserna bland DL-modellerna och kan bevara den höga noggrannheten. Resultaten visade att DL-modeller kan utnyttja kontextuell information fullt ut och fånga rumsliga detaljer i flera skalor från brandkänsliga spektralband för att kartlägga brända områden. Med den unika tidsmässiga bilden har DL-baserade metoder potential att användas för nästa jordobservationssatellit med databehandling ombord och begränsad lagring av tidigare scener. I den framtida studien kommer DL-modeller att undersökas för att upptäcka aktiva bränder från fjärranalysdata med flera upplösningar. Det befintliga problemet med obalanserade märkta data kan lösas med hjälp av en avancerad DL-arkitektur, lämplig konfiguration av träningsdatasetet och förbättrad förlustfunktion. För att ytterligare utforska de skador som orsakas av skogsbränder kommer det framtida arbetet att fokusera på bedömningen av brännskadornas allvarlighetsgrad baserat på DL-modeller genom semantisk segmentering av flera klasser. Dessutom kan översättningen mellan optiska bilder och SAR-bilder baserad på en GAN-modell (Generative Adversarial Network) undersökas för att förbättra kartläggningen av brända områden under olika väderförhållanden. / <p>QC 20210525</p>
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Microsatellite Constellation for Wildfire Monitoring / Mikrosatellitkonstellation för övervakning av skogsbränder

Bruce Rosete, Citlali January 2022 (has links)
I flera års tid har antalet svåra och okontrollerade skogsbränder ökat i antal. Det finns ett behov av att detektera skogsbränder med hjälp av satelliter som har högre tidsupplösning samt högre geometrisk upplösning än de satelliter som är i bruk idag. I detta examensarbete utfördes dels en studie av bildframställningen hos, och dels designen av omloppsbanan till en mikrosatellitkonstellation, som använder sig av nära-infraröd (NIR) och kortvågig infraröd (SWIR) avbildningsteknik med förstärkt geometrisk upplösning och tidsupplösning för övervakning av skogsbränder. En översikt av den nuvarande tekniken visade olika alternativ för kamera: två kommersiella sensorer med ett spektralområde på 0.7 till 1.7 μm och geometrisk upplösning på 140 m respektive 112 m; en kommersiell sensor med ett spektralområde på upp till 2.2 μm och geometrisk upplösning på 168 m; samt ett förslag till sensor med högre geometrisk upplösning på 20 m eller 50 m, som erhålls genom att öka brännvidden. Flera slutsatser nåddes med hänsyn till avbildningen: lämpligheten hos linserna som hittades till respektive sensor verifierades, och det upptäcktes att förvrängningen till följd av jordens rotation ökade med förlängd exponeringstid, vilket även skedde för förhållandet mellan signal och störningar. Ett förslag till en cirkulär, solsynkron, polär omloppsbana med ett dagligen upprepande mönster lades fram. En förenklad metod för beräkning av halva storaxeln tillämpades, och därmed bestämdes en höjd på 561 km och lutning på 97.64°. I enlighet med detta uppskattades antalet satelliter som krävs för både global och regional (Sverige) täckning för alla avbildningsalternativ. För global täckning beräknades antalet satelliter som krävs för att uppnå en geometrisk upplösning på 140.25 m till 15 stycken, medan en geometrisk upplösning på 50 m krävde 84 stycken satelliter. För regional täckning (Sverige) krävdes å andra sidan endast 6 stycken satelliter för att uppnå en geometrisk upplösning på 140.25 m, och 32 stycken för en geometrisk upplösning på 50 m. Detta examensarbete har visat hur många satelliter som behövs för antingen global eller regional täckning så att skogsbränder kan detekteras med högre geometrisk upplösning samt högre tidsupplösning. / For several years, the occurrence of more severe and uncontrolled wildfires has been increasing. There is a need to detect wildfires with a higher spatial and temporal resolution than the ones currently provided by operational satellites. In this thesis, an imager study and orbital design of a microsatellite constellation using near infrared (NIR) and shortwave infrared (SWIR) imagers for wildfire monitoring, with enhanced spatial and temporal resolution, was conducted. After a state of the art review, different alternatives of imaging systems were discerned: two commercial sensors with spectral range of 0.7 to 1.7 μm and spatial resolution of 140 m and 112 m, respectively; one commercial sensor with spectral range up to 2.2 μm and spatial resolution of 168 m; and one sensor proposal with higher spatial resolution of 20 m or 50 m, achieved by increasing the focal length. Several conclusions were reached with regards to the imagers: the appropriateness of lenses found for each sensor was confirmed, the Earth rotation distortion was found to increase as the exposure time is extended, as did the signal-to noise ratio. A proposal for a circular sun-synchronous polar orbit with a daily repeating pattern was made. Applying a simplified method to calculate the semi-major axis, an altitude of 561 km and inclination of 97.64° were determined. Accordingly, the number of satellites for both global and regional (Sweden) coverage was estimated for all imager alternatives. For global coverage, the necessary number of satellites to achieve a spatial resolution of 140.25 m was calculated to be 15 satellites, whereas for a spatial resolution of 50 m the number of satellites increased to 84. On the other hand, for regional coverage (Sweden), the number of satellites to achieve a spatial resolution of 140.25 m were 6, and for a spatial resolution of 50 m the number of satellites was 32. This thesis shows how many satellites are required for either global or regional coverage, considering different imager configurations, to detect wildfires with a higher spatial and temporal resolution.
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POGOREL'ŠČINA (TERRA BRUCIATA) DI N.A. KLJUEV: TRADUZIONE E COMMENTO DEL POEMA / POGOREL'SHCHINA (THE BURNED RUINS) BY N.A. KLYUEV: TRANSLATION INTO ITALIAN AND COMMENTARY

SARRACCO, ROBERTO 28 April 2014 (has links)
Il lavoro propone la traduzione annotata del poema “Pogorel'ščina“ (Terra bruciata, 1928), una delle ultime opere di Nikolaj Alekseevič Kljuev (1884-1937), inedita fino al 1954, e mai apparsa in lingua italiana. La traduzione si mantiene il più possibile aderente al testo originale, che accosta il registro basso del canto popolare e quello alto letterario, liturgico ed epico. Le note al testo illustrano gli arcaismi e i localismi, tipici del linguaggio kljueviano, e approfondiscono alcuni motivi legati al folklore e alla tradizione ortodossa così come a quella vecchio-credente e settaria. Completano il lavoro i dati relativi alla storia redazionale del poema, la cronologia della vita e delle opere dell'autore, fra i protagonisti della cosiddetta “Età d’argento” della poesia russa novecentesca, e un’appendice iconografica. / Our work offers a commented translation of the poem “Pogorel'shchina“ (The Burned Ruins, 1928), one of Nikolai Alekseevich Klyuev’s (1884-1937) last works. It was composed in 1928, remained unpublished until 1954 and was never translated into Italian. In our translation, we have endeavoured to adhere to the original lexicon and syntax of the original text, which combines the low register of the folk songs with the upper, liturgical and epic register. In our notes to the text we illustrate the archaisms and localisms that are typical of Klyuev’s language and explore motifs related to the folklore, to the Orthodox tradition as well as to the Old Believers’ and sectarian tradition. Finally, our work includes the redactional history of the poem, the chronology of the life and works of the author, one of the protagonists of the so called “Silver Age“ of XXth century Russian poetry, and an iconographic appendix.

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