Le but de ce travail de recherche est de contribuer à une meilleure compréhension de la dynamique de propagation et de la miscibilité de jets gravitaires au-dessous d’un liquide ambiant. Des expériences ont été réalisées en laboratoire à l’aide d’une plateforme expérimentale constituée d’un bassin parallélépipédique contenant de l’eau douce et d’un canal d’injection de section rectangulaire de jets gravitaires de concentration constante initiale fixée. Les calculs mathématiques et numériques sont basés sur les modèles RANS (Reynolds-Averaged Navier Stokes equations), k-ε (K-epsilon) et DCE (Diffusion-Convective Equation) de la fraction volumique de l’eau salée pour décrire la propagation et le mélange du jet gravitaire. L’évolution du front du jet obtenue expérimentalement est utilisée pour valider le modèle numérique. Par ailleurs, la comparaison des résultats obtenus sur l’écoulement moyen (z⁄z0.5 =U/Umax) avec ceux des études 2D expérimentales et numériques antérieures ont montré des similarités. La simulation numérique des champs hydrodynamiques montre que la vitesse maximale est atteinte à la position 0.18 z0.5, où z0.5 est la hauteur d’eau pour laquelle la vitesse moyenne u est égale à la moitié de la vitesse maximale Umax. / The aim of this investigation is to contribute to a better understanding of the propagation dynamics and the mixing process of dense gravity currents. The Laboratory experiments proceeded with a fixed initial gravity current concentration in one experimental set-up. The gravity currents are injected using a rectangular injection channel into a rectangular basin containing the ambient lighter liquid. The injection studied is said in unsteady state volume, as the Reynolds number lies in the range 1111 - 3889. The experiments provided the evolution of the boundary interface of the jet, and it is used to validate the numerical model. The numerical model depends on the Reynolds-Averaged Navier Stokes equations (RANS). The k-ε (K-epsilon) and the Diffusion-Convective Equation (DCE) of the saline water volume fraction were used to model the mixing and the propagation of the gravity current jet. On the other hand, comparison of the mean flow (z⁄z0.5 =U/Umax) with previous two-dimensional numerical simulations and experimental measurements have shown similarities. The numerical simulations of the hydrodynamic fields indicate that the velocity maximum at 0.18 z0.5, where z0.5 is the height at which the mean velocity u is the half of the maximum velocity Umax.

La variation spatiale du mouvement sismique a des effets significatifs sur la réponse dynamique des structures de génie civil de grandes dimensions. Dans la pratique courante, l'excitation du mouvement sismique le long de la fondation de la structure est considérée uniforme, approche cependant inadéquate pour les structures de large portance au sol localisées à proximité des failles ou sur des sites présentant une structure du sous-sol latéralement hétérogène. Cette thèse se propose donc de comprendre les facteurs clefs contrôlant localement la variabilité spatiale du mouvement sismique, avec en ligne de mire la mise en place de recommendations en vue d'incorporer ces effets dans l'estimation de l'aléa sismique et le dimensionnement des structures. La première partie de cette thèse s'intéresse à la composante intra-évènement de l'écart-type de la distribution du mouvement sismique en champ proche à l'aide de simulations numériques du mouvement sismique pour des sources étendues présentnat une cinématique de rupture réaliste. Les résultats suggèrent que la variabilité intra-évènement dépend significativement du type de rupture, cette variabilité augmentant avec la distance pour les ruptures bilatérales et diminuant pour les ruptures unilatérales. La seconde partie traite de la caractérisation de la composition du champ d'onde dans la vallée de Koutavos-Argostoli, qui est une vallée de petite dimension et d'épaisseur sédimentaire faible, située sur l'île – sismiquement active - de Céphalonie en Grèce. Les champs d'onde générés par 46 séismes, ayant des magnitudes variant entre 2 et 5 et des distances épicentrales jusqu'à 200 km, ont été analysés à partir de l'enregistrement par deux réseaux denses de capteurs sismologiques. L'algorithme de traitement d'antenne MUSIQUE est utilisé pour extraire la vitesse, l'azimut, le type et la polarisation des ondes dominantes se propageant à travers le réseau. Les résultats montrent clairement d'importantes diffractions d'ondes de surface aux bords de vallée au-delà de la fréquence de résonance de la vallée. Tandis que les ondes de Love dominent clairement le champ d'ondes proche de la fréquence de résonance, les ondes de Rayleigh dominent à plus haute fréquence dans des gammes de fréquences étroites. Par ailleurs, un excellent accord est observé entre les champs d'onde de surface diffractés localement et les caractéristiques d'amplification du site. La “cohérence décalée” de la partie la plus énergétique du signal a été quantifiée pour chaque paire de stations du réseau. En général, la cohérence calculée sur les composantes horizontales diminue avec la distance entre stations et la fréquence. La cohérence sur la composante verticale indique des valeurs relativement fortes à haute fréquence. Les valeurs de cohérence apparaissent très faiblement corrélées à la magnitude, l'azimut et la distance épicentrale du séisme, mais sont au contraire liées aux caractéristiques géométriques de la vallée. La coherence est systématiquement plus forte pour les couples de capteurs orientés selon la direction parallèle à l'axe de la vallée, et moins forte pour des couples de capteurs orientés dans la direction perpendiculaires. Cette observation est en accord avec les résultats du traitement d'antenne: la prédominance d'ondes de surface diffractées sur les bords de la vallée conduit à des mouvements en phase le long de la direction parrallèle à l'axe de la vallée. Les résultats de cette thèse apporte des elements de compréhension sur la variabilité spatiale du movement sismique et ouvrent de nombreuses perspectives d'application. / Spatial variation of earthquake ground motion over short distances significantly affects the dynamic response of engineered structures with large dimensions. In current practices, the ground motion excitation across the foundation of a structure is assumed to be spatially uniform, which becomes inadequate for spatially extended structures in the near-fault region or on sites with lateral inhomogeneity. This PhD thesis seeks to understand the key parameters that locally control the ground motion spatial variability with the intent of putting forth practical propositions for incorporating such effects in seismic design and hazard assessment. The first part of the thesis addresses the within-event component of the standard deviation of ground-motion distribution in near source region by means of numerical simulation of ground motions for extended sources with realistic rupture kinematics. The results suggest that the within-event variability significantly depends on the rupture type, depicting an increase with distance for bilateral ruptures and a decrease for unilateral ruptures. The second part deals with the characterization of seismic wave field at the Koutavos-Argostoli site, a small-size, shallow, alluvial valley located in the seismically active Cephalonia Island in Western Greece. The seismic wave field was investigated from the recordings of a dense seismological array for a set of 46 earthquakes, with magnitude 2 to 5 and epicentral distance up to 200 km. The MUSIQUE array analysis algorithm was used to extract the phase velocity, back-azimuth, type and polarization of the dominant waves crossing the array. The results clearly indicate dominant scattering of seismic surface waves, mainly from the valley-edge directions, beyond the fundamental frequency of the valley. While Love surface waves clearly dominate the wave field close to the resonance frequency, Rayleigh waves strongly dominate only in relatively narrow frequency bands at higher frequency. Besides, an excellent consistency is observed between the dominance of the identified surface wave type in the wave field and the site amplification. The "lagged coherency" of the most energetic part of the ground motion has been quantified for each station-pair within the array. In general, spatial coherency estimated from the horizontal components exhibit decays with frequency and interstation distance. Estimates from the vertical component exhibit rather larger values at some higher frequencies. Although coherency does not show any consistent trend indicating dependence on the magnitude, back-azimuth or site-to-source distance of the event, it seems to be primarily controlled by the site geometry. Larger coherency is systematically observed when the station pair is oriented parallel to the valley axis, while lower values are observed in the perpendicular direction. This observation proves to be consistent with the MUSIQUE analysis results: the predominance of scattered surface waves propagating across the valley implies an in-phase motion along valley-parallel direction and out-of-phase motion along valley-perpendicular direction. The findings of the present research are expected to contribute in enhancing our understanding of spatial variability of ground motion and improving the coherency models used in engineering. This work also opens up new insights and many questions in need of further investigation.

A tese versa sobre a detecção e avaliação de padrões de coexistência de espécies arbóreas, buscando esclarecer as relações entre a diversidade fito-estrutural e os fatores condicionantes em escalas local e regional em uma zona de contato entre duas regiões fitoecológicas (Florestas Ombrófilas Mista e Densa). O trabalho está dividido em duas abordagens; a primeira trata de um inventário fitossociológico de comunidades definidas como “sítios”, onde o grau de singularidade local é avaliado através da identidade das espécies com maior valor de importância (VI) estrutural e de suas possíveis conexões fitogeográficas, bem como através de indicadores de diversidade alfa e beta. Na segunda abordagem, comunidades são definidas estatisticamente (Multivariada, Análise do Valor Indicador das Espécies) com base na composição e abundância de espécies (área basal dos troncos), testando-se a hipótese de que comunidades distintas devem diferir pelo menos na diversidade específica, fertilidade do solo e ou produtividade primária (produção de serrapilheira PS). O estudo foi realizado no Centro de Pesquisas e Conservação da Natureza Pró-Mata, localizado na borda sudeste do Planalto Meridional Brasileiro (29o30’S; 50o11’W). Cinco sítios de 100m x 100m (dois sítios no planalto, dois na encosta e um na borda planalto-encosta) foram selecionados, onde em cada sítio as árvores (DAP>10 cm) foram medidas e determinadas em vinte e uma unidades amostrais de 100m2 (regularmente distribuídas). Sessenta e seis espécies foram levantadas, no conjunto Cabralea canjerana e Myrcia retorta tiveram os maiores valores de importância. A primeira caracteriza a encosta e a segunda o planalto, sendo ambas co-dominantes no sítio da borda do planalto-encosta. Riqueza e diversidade foram maiores nessa borda, menor no planalto e intermediária na encosta. A beta-diversidade apresenta-se maior com medidas de abundância do que apenas com a composição de espécie, em função da diferenciação das dominantes, caracterizando comunidades discretas, indicando ao mesmo tempo um contínuo gradiente florístico. As análises de ordenação e agrupamento foram utilizadas com dois tamanhos de unidade amostral (100 m2 e 500 m2), das quais somente a última apresentou padrões interpretáveis, similares aos obtidos fitossociologicamente nos sítios, onde dois principais tipos de vegetação apresentam afinidades fitogeográficas e riqueza de espécies peculiares. Os subgrupos refletiram processos histórico-ecológicos mais recentes, como a perturbação antrópica e condições locais especiais. A determinação de espécies com valores indicadores significativos é útil para a diferenciação ecológica dos tipos de comunidades. Apenas uma comunidade diferiu significativamente das demais na fertilidade do solo, devido à condição especial topográfica e litológica. A produção de serrapilheira destas florestas foi similar aos valores médios das florestas brasileiras tropicais e subtropicais. Conclui-se que, na zona de transição estudada, tende a ter um ecótono da vegetação associado à transição geomorfológica planalto-encosta. Algumas considerações sobre o alcance metodológico de detecção de biodiversidade e das perspectivas de pesquisas integradas sobre os processos ecossistêmicos são apresentadas. / This thesis searches to detect patterns of the arboreal species coexistence on a transition zone of two phyto-ecological regions, Mixed and Dense Rainforests, contributing to the knowledge of ecological processes on the local to regional scale. The work is divided in two approaches; the first is a phytosociological inventories aiming to answer if in this zone exists a set of local communities with similar floristic-structural patterns, or not, and what are their phytogeographical affinities; the second tests the hypothesis that the communities types statistically defined have indicator species and differs in specific diversity attributes, soil fertility and the primary productivity (litterfall). The study was carried out at CPCN Pró-Mata, a research center located on the southeastern border of the Meridional Brazilian Plateau (29o30’S; 50o11’W). Five sites of 100 x 100m (two plateau sites, two slope sites, and one plateau-slope site) were selected; the trees (DBH>10cm) were measured and determined and twenty-one sampling units of 100m2 (regularly distributed), in each site. Sixty-six species were surveyed. Cabralea canjerana and Myrcia retorta had the highest importance value indexes. The first species characterizes the slope; the second species characterizes the plateau; and both are co-dominant at the slope-plateau site. Richness and diversity (Shannon index) were higher at slope-plateau transition, lower at the plateau and intermediate at the slopes. The Beta diversity shows that the sharpness between slope and plateau communities is more associated to species abundance than to species composition only. The Ordination and Cluster analyses were used with two sized sampling units (100 m2 and 500m2), which only the latter showed interpretable patterns, similar to those phytosociological results, where emerges the two main vegetation types indicated the broader regional floristic affinities and its influence on species richness. The sub-groups reflected more recent local historical-ecological processes, mainly identified as anthropic disturbance regime and special local conditions. The Indicator Species Analysis was very responsive to the present objective helping to define the best indicative species and ecological context. Soils differ significantly only for one group, differentiated by special topographic condition and lithologic origin. The annual litterfall of these forests were equivalent among sites and they are similar to register for average the tropical and subtropical Brazilian forests. Conclude that in this transition zone trends to have a vegetation ecotone is associated to the geomorphologic transition slope-plateau. Then, communities types statistically defined reflect hierarchically phytoecological regional affinities and particular ecological conditions. Some considerations about methodological biodiversity detection integrated to researches about ecosystem process are shown.

As we navigate the world, for example when driving a car from our home to the work place, we continuously perceive the 3D structure of our surroundings and intuitively recognise the objects we see. Such capabilities help us in our everyday lives and enable free and accurate movement even in completely unfamiliar places. We largely take these abilities for granted, but for robots, the task of understanding large outdoor scenes remains extremely challenging. In this thesis, I develop novel algorithms for (near) real-time dense 3D reconstruction and semantic segmentation of large-scale outdoor scenes from passive cameras. Motivated by "smart glasses" for partially sighted users, I show how such modeling can be integrated into an interactive augmented reality system which puts the user in the loop and allows her to physically interact with the world to learn personalized semantically segmented dense 3D models. In the next part, I show how sparse but very accurate 3D measurements can be incorporated directly into the dense depth estimation process and propose a probabilistic model for incremental dense scene reconstruction. To relax the assumption of a stereo camera, I address dense 3D reconstruction in its monocular form and show how the local model can be improved by joint optimization over depth and pose. The world around us is not stationary. However, reconstructing dynamically moving and potentially non-rigidly deforming texture-less objects typically require "contour correspondences" for shape-from-silhouettes. Hence, I propose a video segmentation model which encodes a single object instance as a closed curve, maintains correspondences across time and provide very accurate segmentation close to object boundaries. Finally, instead of evaluating the performance in an isolated setup (IoU scores) which does not measure the impact on decision-making, I show how semantic 3D reconstruction can be incorporated into standard Deep Q-learning to improve decision-making of agents navigating complex 3D environments.

LIRA, Daniely Lidiany Costa. Assoreamento em densas redes de reservatórios: o caso da bacia hidrográfica da barragem Pereira de Miranda, Ce. 2012. 86 f. Dissertação (mestrado) - Universidade Federal do Ceará, Departamento de Engenharia Agricola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2012. / Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-20T16:12:24Z No. of bitstreams: 1 2012_dis_dlclira.pdf: 3463400 bytes, checksum: ace09712a6d5128d789c8d04b03b5bd0 (MD5) / Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-20T16:13:06Z (GMT) No. of bitstreams: 1 2012_dis_dlclira.pdf: 3463400 bytes, checksum: ace09712a6d5128d789c8d04b03b5bd0 (MD5) / Made available in DSpace on 2016-06-20T16:13:06Z (GMT). No. of bitstreams: 1 2012_dis_dlclira.pdf: 3463400 bytes, checksum: ace09712a6d5128d789c8d04b03b5bd0 (MD5) Previous issue date: 2012 / The present study aims at analyzing the impacts of the dense reservoir network of the Pereira de Miranda catchment in its sediment yield and water storage capacity of the system. The studied area is located in the Brazilian Semiarid region, in the State of Ceará, with an area of approximately 3230 km2. It has an average annual rainfall of 854 mm and an annual potential evaporation of 1464 mm. The predominant soil and vegetation type are luvissolo and open shrub caatinga. Satellite imageries from wet years were used to identify the reservoirs of the catchment. Erosion units were identified derived from map overlay of the parameters of the Universal Soil Loss Equation (USLE), which enables the estimation of sediment yield and the identification of areas with high sediment production. A simplified model was used to simulate the sediment routing through the dense reservoir network of the basin. For the estimation of sedimentation at the Pereira de Miranda Reservoir, different scenarios of the system structure were considered. A mean erosion rate of 59 t.ha-1.year-1 was estimated for the basin, in which 42% of the basin area presents a moderate degree of erosion. According to the model, silting of the Pereira de Miranda reservoir may vary from 1.1 to 2.6 %.decade-1, depending on the scenario considered. One may observe that upstream reservoirs are able to retain until 58% of the sediments that would reach the Pereira de Miranda reservoir. The very small reservoirs, with storage capacity below 100,000 m³, are able to retain almost 8% of the generated sediments, although they represent just 1.83% of the system water storage capacity. Sensitivity analysis shows that the sediment retention capacity of the upstream reservoirs may vary from 20 to 58%, depending on the system structure concerning the presence of upstream reservoirs from different size classes. One may still conclude that the reduction rate of water storage capacity at the system as a function of reservoir siltation is relatively larger then that observed for the Pereira de Miranda reservoir, due to the upstream sediment retention. / O presente estudo tem como objetivo analisar os impactos da densa rede de reservatórios da bacia hidrográfica do açude Pereira de Miranda (Pentecoste) na produção de sedimentos e capacidade de armazenamento hídrica do sistema. A bacia estudada localiza-se no Nordeste Brasileiro, no Estado do Ceará, com uma área de aproximadamente 3.230 km2. Possui uma precipitação média anual de 854 mm e evaporação potencial média observada em tanque do tipo classe A é de 1.464 mm. O solo e a vegetação predominante são do tipo luvissolo e caatinga arbustiva aberta. Imagens de satélite de anos úmidos foram utilizadas para levantamento da açudagem na bacia. Foram identificadas unidades de erosão derivadas da sobreposição de mapas dos parâmetros da Equação Universal de Perdas do Solo (EUPS), o que permitiu a estimativa da erosão localizada na bacia e identificação de áreas potencialmente produtoras de sedimento. Um modelo simplificado foi utilizado para simular a propagação de sedimentos pela densa rede de reservatórios da bacia. Para estimativa do assoreamento no reservatório Pereira de Miranda, diferentes cenários de estrutura do sistema foram considerados. Foi estimada uma taxa de erosão média na bacia de 59 t.ha-1.ano-1, sendo que 42% da área da bacia apresenta grau de erosão moderado. De acordo com o modelo, o assoreamento do reservatório Pentecoste pode variar de 1,1 a 2,6% por década, dependendo do cenário considerado. Observa-se ainda que os reservatórios de montante podem reter até 58% do sedimento que chegaria ao açude Pereira de Miranda. Os reservatórios muito pequenos, com capacidade de até 100.000 m³, embora representem apenas 1,83% da disponibilidade hídrica do sistema, são capazes de reter quase 8% do total de sedimento produzido. Análises de sensibilidade mostram que a capacidade de retenção de sedimentos nos reservatórios de montante pode variar de 20 a 58%, dependendo da estrutura do sistema quanto à existência de reservatórios de diferentes classes de tamanho. Constata-se ainda que a taxa de redução da capacidade de armazenamento hídrica do sistema em função do assoreamento dos reservatórios de montante é relativamente maior do que a observada para o açude Pereira de Miranda, devido à retenção de sedimentos a montante.

In the paper [HSS] Herrlich, Salicrup and Strecker were able to show that Kuratowski / Mrowka's Theorem concerning compactness for topological spaces could be applied to a wider setting. In this dissertation, which is based on the paper [F subscript 1], we interpret Kuratowski / Mrowka's result in the category R-Mod. Chapter One deals mainly with the preliminary definitions and results and we also show that there is a 1-1 correspondence between torsion theories and standard factorisation systems. In Chapter Two we, obtain for every torsion theory T, a theory of T-compactness which is an extension of the definition of compactness found in [HSS]. We then obtain a characterisation of T-compactness under certain conditions on the ring R and torsion theory T. In Chapter Three we examine the class of T-compact R-modules more closely when the ring R is T-hereditary and T-noetherian. We also obtain further characterisation of T-compactness under these additional conditions. In Chapter Four we show that many topological results have analogues in R-Mod. / Mathematical Sciences / M. Sc. (Mathematics)

A tese versa sobre a detecção e avaliação de padrões de coexistência de espécies arbóreas, buscando esclarecer as relações entre a diversidade fito-estrutural e os fatores condicionantes em escalas local e regional em uma zona de contato entre duas regiões fitoecológicas (Florestas Ombrófilas Mista e Densa). O trabalho está dividido em duas abordagens; a primeira trata de um inventário fitossociológico de comunidades definidas como “sítios”, onde o grau de singularidade local é avaliado através da identidade das espécies com maior valor de importância (VI) estrutural e de suas possíveis conexões fitogeográficas, bem como através de indicadores de diversidade alfa e beta. Na segunda abordagem, comunidades são definidas estatisticamente (Multivariada, Análise do Valor Indicador das Espécies) com base na composição e abundância de espécies (área basal dos troncos), testando-se a hipótese de que comunidades distintas devem diferir pelo menos na diversidade específica, fertilidade do solo e ou produtividade primária (produção de serrapilheira PS). O estudo foi realizado no Centro de Pesquisas e Conservação da Natureza Pró-Mata, localizado na borda sudeste do Planalto Meridional Brasileiro (29o30’S; 50o11’W). Cinco sítios de 100m x 100m (dois sítios no planalto, dois na encosta e um na borda planalto-encosta) foram selecionados, onde em cada sítio as árvores (DAP>10 cm) foram medidas e determinadas em vinte e uma unidades amostrais de 100m2 (regularmente distribuídas). Sessenta e seis espécies foram levantadas, no conjunto Cabralea canjerana e Myrcia retorta tiveram os maiores valores de importância. A primeira caracteriza a encosta e a segunda o planalto, sendo ambas co-dominantes no sítio da borda do planalto-encosta. Riqueza e diversidade foram maiores nessa borda, menor no planalto e intermediária na encosta. A beta-diversidade apresenta-se maior com medidas de abundância do que apenas com a composição de espécie, em função da diferenciação das dominantes, caracterizando comunidades discretas, indicando ao mesmo tempo um contínuo gradiente florístico. As análises de ordenação e agrupamento foram utilizadas com dois tamanhos de unidade amostral (100 m2 e 500 m2), das quais somente a última apresentou padrões interpretáveis, similares aos obtidos fitossociologicamente nos sítios, onde dois principais tipos de vegetação apresentam afinidades fitogeográficas e riqueza de espécies peculiares. Os subgrupos refletiram processos histórico-ecológicos mais recentes, como a perturbação antrópica e condições locais especiais. A determinação de espécies com valores indicadores significativos é útil para a diferenciação ecológica dos tipos de comunidades. Apenas uma comunidade diferiu significativamente das demais na fertilidade do solo, devido à condição especial topográfica e litológica. A produção de serrapilheira destas florestas foi similar aos valores médios das florestas brasileiras tropicais e subtropicais. Conclui-se que, na zona de transição estudada, tende a ter um ecótono da vegetação associado à transição geomorfológica planalto-encosta. Algumas considerações sobre o alcance metodológico de detecção de biodiversidade e das perspectivas de pesquisas integradas sobre os processos ecossistêmicos são apresentadas. / This thesis searches to detect patterns of the arboreal species coexistence on a transition zone of two phyto-ecological regions, Mixed and Dense Rainforests, contributing to the knowledge of ecological processes on the local to regional scale. The work is divided in two approaches; the first is a phytosociological inventories aiming to answer if in this zone exists a set of local communities with similar floristic-structural patterns, or not, and what are their phytogeographical affinities; the second tests the hypothesis that the communities types statistically defined have indicator species and differs in specific diversity attributes, soil fertility and the primary productivity (litterfall). The study was carried out at CPCN Pró-Mata, a research center located on the southeastern border of the Meridional Brazilian Plateau (29o30’S; 50o11’W). Five sites of 100 x 100m (two plateau sites, two slope sites, and one plateau-slope site) were selected; the trees (DBH>10cm) were measured and determined and twenty-one sampling units of 100m2 (regularly distributed), in each site. Sixty-six species were surveyed. Cabralea canjerana and Myrcia retorta had the highest importance value indexes. The first species characterizes the slope; the second species characterizes the plateau; and both are co-dominant at the slope-plateau site. Richness and diversity (Shannon index) were higher at slope-plateau transition, lower at the plateau and intermediate at the slopes. The Beta diversity shows that the sharpness between slope and plateau communities is more associated to species abundance than to species composition only. The Ordination and Cluster analyses were used with two sized sampling units (100 m2 and 500m2), which only the latter showed interpretable patterns, similar to those phytosociological results, where emerges the two main vegetation types indicated the broader regional floristic affinities and its influence on species richness. The sub-groups reflected more recent local historical-ecological processes, mainly identified as anthropic disturbance regime and special local conditions. The Indicator Species Analysis was very responsive to the present objective helping to define the best indicative species and ecological context. Soils differ significantly only for one group, differentiated by special topographic condition and lithologic origin. The annual litterfall of these forests were equivalent among sites and they are similar to register for average the tropical and subtropical Brazilian forests. Conclude that in this transition zone trends to have a vegetation ecotone is associated to the geomorphologic transition slope-plateau. Then, communities types statistically defined reflect hierarchically phytoecological regional affinities and particular ecological conditions. Some considerations about methodological biodiversity detection integrated to researches about ecosystem process are shown.

This thesis explores motion trajectory-based approaches to recognize human actions in real-world, unconstrained videos. Recognizing actions is an important task in applications such as video retrieval, surveillance, human-robot interactions, analysis of sports videos, summarization of videos, behaviour monitoring, etc. There has been a considerable amount of research done in this regard. Earlier work used to be on videos captured by static cameras where it was relatively easy to recognise the actions. With more videos being captured by moving cameras, recognition of actions in such videos with irregular camera motion is still a challenge in unconstrained settings with variations in scale, view, illumination, occlusion and unrelated motions in the background. With the increase in videos being captured from wearable or head-mounted cameras, recognizing actions in egocentric videos is also explored in this thesis. At first, an effective motion segmentation method to identify the camera motion in videos captured by moving cameras is explored. Next, action recognition in videos captured in normal third-person view (perspective) is discussed. Further, the action recognition approaches for first-person (egocentric) views are investigated. First-person videos are often associated with frequent unintended camera motion. This is due to the motion of the head resulting in the motion of the head-mounted cameras (wearable cameras). This is followed by recognition of actions in egocentric videos in a multicamera setting. And lastly, novel feature encoding and subvolume sampling (for “deep” approaches) techniques are explored in the context of action recognition in videos. The first part of the thesis explores two effective segmentation approaches to identify the motion due to camera. The first approach is based on curve fitting of the motion trajectories and finding the model which best fits the camera motion model. The curve fitting approach works when the trajectories generated are smooth enough. To overcome this drawback and segment trajectories under non-smooth conditions, a second approach based on trajectory scoring and grouping is proposed. By identifying the instantaneous dominant background motion and accordingly aggregating the scores (denoting the “foregroundness”) along the trajectory, the motion that is associated with the camera can be separated from the motion due to foreground objects. Additionally, the segmentation result has been used to align videos from moving cameras, resulting in videos that seem to be captured by nearly-static cameras. In the second part of the thesis, recognising actions in normal videos captured from third-person cameras is investigated. To this end, two kinds of descriptors are explored. The first descriptor is the covariance descriptor adapted for the motion trajectories. The covariance descriptor for a trajectory encodes the co-variations of different features along the trajectory’s length. Covariance, being a second-order encoding, encodes information of the trajectory that is different from that of the first-order encoding. The second descriptor is based on Granger causality. The novel causality descriptor encodes the “cause and effect” relationships between the motion trajectories of the actions. This type of interaction descriptors captures the causal inter-dependencies among the motion trajectories and encodes complimentary information different from those descriptors based on the occurrence of features. The causal dependencies are traditionally computed on time-varying signals. We extend it further to capture dependencies between spatiotemporal signals and compute generalised causality descriptors which perform better than their traditional counterparts. An egocentric or first-person video is captured from the perspective of the personof-interest (POI). The POI wears a camera and moves around doing his/her activities. This camera records the events and activities as seen by him/her. The POI who is performing actions or activities is not seen by the camera worn by him/her. Activities performed by the POI are called first-person actions and third-person actions are those done by others and observed by the POI. The third part of the thesis explores action recognition in egocentric videos. Differentiating first-person and third-person actions is important when summarising/analysing the behaviour of the POI. Thus, the goal is to recognise the action and the perspective from which it is being observed. Trajectory descriptors are adapted to recognise actions along with the motion trajectory ranking method of segmentation as pre-processing step to identify the camera motion. The motion segmentation step is necessary to remove unintended head motion (camera motion) during video capture. To recognise actions and corresponding perspectives in a multi-camera setup, a novel inter-view causality descriptor based on the causal dependencies between trajectories in different views is explored. Since this is a new problem being addressed, two first-person datasets are created with eight actions in third-person and first-person perspectives. The first dataset is a single camera dataset with action instances from first-person and third-person views. The second dataset is a multi-camera dataset with each action instance having multiple first-person and third-person views. In the final part of the thesis, a feature encoding scheme and a subvolume sampling scheme for recognising actions in videos is proposed. The proposed Hyper-Fisher Vector feature encoding is based on embedding the Bag-of-Words encoding into the Fisher Vector encoding. The resulting encoding is simple, effective and improves the classification performance over the state-of-the-art techniques. This encoding can be used in place of the traditional Fisher Vector encoding in other recognition approaches. The proposed subvolume sampling scheme, used to generate second layer features in “deep” approaches for action recognition in videos, is based on iteratively increasing the size of the valid subvolumes in the temporal direction to generate newer subvolumes. The proposed sampling requires lesser number of subvolumes to be generated to “better represent” the actions and thus, is less computationally intensive compared to the original sampling scheme. The techniques are evaluated on large-scale, challenging, publicly available datasets. The Hyper-Fisher Vector combined with the proposed sampling scheme perform better than the state-of-the-art techniques for action classification in videos.

Made available in DSpace on 2016-12-12T20:12:28Z (GMT). No. of bitstreams: 1 PGEF13MA004.pdf: 2086804 bytes, checksum: 908b42e640408298b84be4a9a2cef57c (MD5) Previous issue date: 2013-11-20 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The Family Agriculture in the State of Santa Catarina corresponds to 87% of agricultural establishments. This high percentage shows the relevance of the activity in the State. In the municipality of Biguaçu , SC , where family farming is present in a striking and effective way, farmers use the derived energy resources of the secondary formations of the Ombrophilous Dense Forest, through the system " roça-de-toco". The production of charcoal becomes tool of great socio-economic importance for families in these areas. Thus, studies that characterize and evaluate the quality of coal produced from the main species used for charcoal production on family farms are of paramount importance as it will allow farmers to improve production process and add value and quality to the product. Therefore the aim of this study was to determine the quality of wood and charcoal produced by five forest species used by farmers in the municipality of Biguaçu, SC. To determine the quality of wood, five trees were collected from each species. From the same nine disks each, for the analysis of physical properties,analysis of the energetic properties and charring in the laboratory. For carbonization procedure used three of the five tree species studied, which consisted of making an average of seven specimens for each tree, varying according to the diameter of the tree, with approximate dimensions of 2 x 2 x 2.5 cm. Subsequently, the specimens were wrapped in aluminum paper identified, and placed in a muffle furnace with a final temperature of 450 ° C. After carbonization were certain the physical, energetic and anatomical properties of the coal. The results revealed by global analysis of the physical and energetic properties of the wood, the Mimosa scabrella (MEB = 0.578 g/cm³ and PCS = 4,400 Kcal/Kg), Hieronyma alchorneoides (MEB = 0.530 g/cm³ and PCS = 4,346 Kcal/Kg), Miconia cinnamomifolia (MEB = 0.561 g/cm³ and PCS = 4,268 Kcal/Kg) and Pera glabrata (MEB = 0,639 g/cm³ and PCS = 4,311 Kcal/Kg) will perform better for the production of coal. There was strong correlation between basic density of wood and apparent density of coal; highlighting the M. scabrella, H. alchorneoides, M. cinnamomifolia and P. glabrata. In general the coal produced by farmers showed better energy characteristics (PCS = 7.215 Kcal/Kg; TV = 26,66 %; TC = 2,56 % e CF = 71,04 %). Anatomical analysis of coal indicated that the anatomical structure of the wood is maintained during the carbonization process used, with a final temperature of 450 °C, allowing the identification of the material on the basis of cell components / A Agricultura Familiar no Estado de Santa Catarina corresponde a 87% dos estabelecimentos agropecuários. Este elevado percentual mostra a relevância da atividade no Estado. No município de Biguaçu, SC, onde a Agricultura Familiar se faz presente de forma marcante e efetiva, os agricultores utilizam os recursos energéticos oriundos das formações secundárias da Floresta Ombrófila Densa, através do sistema roça-de-toco . A produção de carvão vegetal torna-se ferramenta de grande importância socioeconômica para as famílias inseridas nestas áreas. Desta forma, trabalhos que caracterizem e avaliem a qualidade do carvão produzido a partir das principais espécies utilizadas para a produção de carvão vegetal na agricultura familiar são de suma importância, pois permitirão aos agricultores melhorar o processo produtivo e agregar valor e qualidade ao produto. Portanto o objetivo deste trabalho foi determinar a qualidade da madeira e do carvão vegetal produzido por cinco espécies florestais utilizadas pelos agricultores familiares do município de Biguaçu, SC. Para a determinação da qualidade da madeira, coletaram-se cinco árvores de cada espécie. A partir das mesmas foram serrados nove discos de cada uma, destinados às análises das propriedades físicas, análises das propriedades energéticas e carbonização em laboratório. O procedimento de carbonização utilizou três árvores das cinco espécies estudadas, onde consistiu na confecção de em média sete corpos de prova para cada árvore, variando conforme o diâmetro da árvore, com dimensões aproximadas de 2 x 2 x 2,5 cm. Posteriormente, os corpos de prova foram envolvidos com papel alumínio, identificados, e colocados em forno mufla com temperatura final de 450ºC. Após a carbonização foram determinadas as propriedades físicas, energéticas e anatômicas do carvão. Os resultados revelaram através da análise global das propriedades físicas e energéticas da madeira, que a Mimosa scabrella (MEB = 0,578 g/cm³ e PCS = 4.400 Kcal/Kg), Hieronyma alchorneoides (MEB = 0,530 g/cm³ e PCS = 4.346 Kcal/Kg), Miconia cinnamomifolia (MEB = 0,561 g/cm³ e PCS = 4.268 Kcal/Kg) e Pera glabrata (MEB = 0,639 Kcal/Kg e PCS = 4.311 Kcal/Kg) terão melhor desempenho para a produção de carvão. Existiu forte correlação entre massa específica básica da madeira e massa específica aparente do carvão; destacando-se a M. scabrella, H. alchorneoides, M. cinnamomifolia e P. glabrata. Em termos gerais o carvão produzido pelos agricultores apresentou melhores características energéticas (PCS = 7.215 Kcal/Kg; TV = 26,66 %; TC = 2,56 % e CF = 71,04 %). A análise anatômica do carvão indicou que a estrutura anatômica da madeira se mantém durante o processo de carbonização utilizado, com temperatura final de 450ºC, podendo-se identificar o material com base nas células componentes

Le Piégeage et le Stockage du dioxyde de Carbone (PSC) est reconnu comme ayant un rôle important dans la lutte contre le changement climatique et la réduction d’émissions de dioxyde de carbone (CO2). Ce processus consiste à capturer le CO2 des sources anthropiques, et le transporter vers des sites de stockage appropriés. Le transport de telles quantités de CO2 entraîne de nouveaux défis pour les concepteurs et les opérateurs des gazoducs. Parmi ces défis, nous citons : le comportement de phase du CO2, la température atteinte lors de la décompression, la présence des différentes impuretés et la pression de service très élevée. Malgré l’enjeu important, et contrairement au gazoduc de transport de gaz naturel et de pétrole, peu d’études ont été consacrées à la sûreté et la rentabilité des gazoducs de transport du CO2. À l’égard de ces défis industriels, cette étude a été menée pour identifier et comprendre les mécanismes de rupture des gazoducs, à haute pression, transportant du CO2 supercritique. Ce travail a engagé la mise au point d’une nouvelle approche qui anticipe l’éclatement du gazoduc. Pour répondre à cette problématique, nous avons utilisé en premier lieu une approche théorique basée sur les fondamentaux de la Mécanique de la Rupture. En second lieu, et en conjonction avec la méthode des éléments finis, nous avons développé un outil numérique robuste. L’ultime objectif de ces travaux de recherche est d’enrichir les codes de dimensionnement des gazoducs, souvent restreints au transport de gaz naturel et au matériau à faible ténacité. De plus, cette thèse apporte une large base de données d’essais de ténacité à basse température liés à des séries d’analyses par éléments finis sous le code de calcul Abaqus 12.6. La finalité de notre recherche réside dans la proposition d’une méthodologie complète d’évaluation des risques d’éclatement des gazoducs en fonction du matériau et de la nature du fluide transporté / Capture, transport, and storage of Carbon dioxide are well-known applications for their key role in the field of climate change and reduction of CO2 emissions. This process involves the use of some particular technologies, not only to collect and concentrate the CO2 emitted by the anthropogenic sources but also to transport it to a suitable storage location. The transport of such a big quantity of CO2 creates new challenges for designers and pipeline operators. For instance, CO2 phase behavior, the temperature reached during the decompression phase, the presence of various impurities as well as the high operating pressure. Contrary to natural gas and oil transportation structures, a very few studies have raised the issue of the integrity of CO2 pipeline. In order to meet the industry needs particularly in this CO2 integrity application, the present research was conducted to identify and to better comprehend pipeline failure mechanisms at high pressures. This work includes the development of a new numerical approach about running ductile fracture arrest for high pressure gas pipeline. To address this issue, we have initially used a theoretical approach based on the fundamental knowledge of Fracture Mechanics. Based on the crack-tip opening angle (CTOA) fracture criterion and the finite element method along with the node release technique, a new two-curve method (TCM) was proposed for the prediction of gas pipelines’ crack arrestability. The results of this newly developed method were discussed and compared to those obtained by using other methods commonly employed in the Fracture mechanics, for instance, Battelle-TCM, HLP and HLP-Sumitomo method