In large scale entity-level military force-on-force simulations it is essential to know when one entity can visibly see another entity. This visibility determination plays an important role in the simulation and can affect the outcome of the simulation. When virtual Computer Generated Forces (CGF) are introduced into the simulation these intervisibilities must now be calculated by the virtual entities on the battlefield. But as the simulation size increases so does the complexity of calculating visibility between entities. This thesis presents an algorithm for performing these visibility calculations using Graphical Processing Units (GPU) instead of the Central Processing Units (CPU) that have been traditionally used in CGF simulations. This algorithm can be distributed across multiple GPUs in a cluster and its scalability exceeds that of CGF-based algorithms. The poor correlations of the two visibility algorithms are demonstrated showing that the GPU algorithm provides a necessary condition for a "Fair Fight" when paired with visual simulations.

Devido às dificuldades encontradas na Medicina Veterinária com relação à circulação extracorpórea, despertou-se o interesse pela técnica de parada circulatória total (\"Inflow Occlusion\") para correção cirúrgica de algumas patologias cardíacas, principalmente estenose de valvas semi-lunares. O objetivo deste trabalho consistiu em comparar as possíveis alterações hemodinâmicas que podem ocorrer em cães submetidos à parada circulatória total através da técnica do \"Inflow Occlusion\" por diferentes períodos de tempo. Utilizou-se neste estudo, doze cães, subdivididos em dois grupos, sendo submetidos à parada circulatória total, por sete ou oito minutos. Realizou-se análise hemodinâmica durante quatro momentos do período transoperatório. Os parâmetros de oxigenação foram obtidos por meio da conjunção dos dados fornecidos pelo cateter de artéria pulmonar e pela análise hemogasométrica. Diferença estatisticamente significativa foi encontrada na comparação entre os grupos avaliados, cinco minutos após a restituição da circulação (momento M3), para a pressão arterial média (PAM) e para o índice de trabalho sistólico do ventrículo direito (ITSVD) e do ventrículo esquerdo (ITSVE). Ocorreram dois óbitos transoperatórios no grupo de animais submetidos à oito minutos de parada circulatória total, devido a fibrilação ventricular. Frente aos óbitos ocorridos, conclui-se que o \"Inflow Occlusion\" foi exequível em cães sadios por sete minutos, sendo contra-indicado para períodos de oito minutos. Entretanto, estudos clínicos envolvendo a técnica em questão, precisam ser realizados para que a referida técnica possa ser aplicada, seguramente, em animais portadores de disfunções cardiovasculares. / Because of difficulties related to extracorporeal circulation in Veterinary Medicine, more interest occurred about circulatory arrest trough \"Inflow Occlusion\" technique to correct surgically some cardiac pathologies, such as semilunar valves stenosis. The aim of this study was to compare possible hemodynamic alterations that can occur in dogs submitted to circulatory arrest using \"Inflow Occlusion\" technique for different periods of time. Twelve mongrel dogs were used in this study divided in two groups, each one submitted to seven or eight minutes of total circulatory arrest. Hemodynamic evaluation was realized during four moments on transoperatory period. Oxygenation parameters were obtained trough pulmonary artery catheter data and hemogasometric analysis. Statistical difference between groups were found on M3 moment, five minutes after circulatory arrest, for mean arterial pressure (MAP), right ventricular systolic stroke index (RVSSI) and left ventricular systolic stroke index (LVSSI). There were two transoperatory deaths on group B, because ventricular fibrillation. Because these deaths, we can say that \"Inflow Occlusion\" can be realized up to seven minutes on healthy dogs and is contra-indicated for periods of eight minutes. However, clinical studies should be performed in order to use this technique routinely with safe in dogs presenting cardiovascular abnormalities.

De nos jours, les logiciels doivent continuellement évoluer et intégrer toujours plus de fonctionnalités pour ne pas devenir obsolètes. C'est pourquoi, la maintenance représente plus de 60% du coût d'un logiciel. Pour réduire les coûts de programmation, les fonctionnalités sont programmées plus rapidement, ce qui induit inévitablement une baisse de qualité. Comprendre l’évolution du logiciel est donc devenu nécessaire pour garantir un bon niveau de qualité et retarder le dépérissement du code. En analysant à la fois les données sur l’évolution du code contenues dans un système de gestion de versions et les données quantitatives que nous pouvons déduire du code, nous sommes en mesure de mieux comprendre l'évolution du logiciel. Cependant, la quantité de données générées par une telle analyse est trop importante pour être étudiées manuellement et les méthodes d’analyses automatiques sont peu précises. Dans ce mémoire, nous proposons d'analyser ces données avec une méthode semi automatique : la visualisation. Eyes Of Darwin, notre système de visualisation en 3D, utilise une métaphore avec des quartiers et des bâtiments d'une ville pour visualiser toute l'évolution du logiciel sur une seule vue. De plus, il intègre un système de réduction de l'occlusion qui transforme l'écran de l'utilisateur en une fenêtre ouverte sur la scène en 3D qu'il affiche. Pour finir, ce mémoire présente une étude exploratoire qui valide notre approche. / Software must continuously evolve and integrate more functionalities to remain useful. Consequently, more than 60% of a software system's cost is related to maintenance. To reduce this cost, programming must performed faster, witch leads to a decrease of the system code's quality. Therefore, understanding software evolution is becoming a necessity to prevent code decay and to increase the system life span. To ease software understanding, we perform a cross analysis of the historical data extracted from a version control system, with quantitative data that we obtain from the source code. However, the significant amount of data generated by this kind of analysis makes it necessary to have tools to support the maintainer’s analysis. First, tools help because examining them manually is impossible. Second, they help because automatics methods are not accurate enough. We present a new semiautomatic approach to help analysis. Our 3D visualization system, Eyes Of Darwin, uses a cityscape metaphor to show software's evolution on a single view. It integrates an occlusion reduction system, witch turns the screen to an open window on the 3D world. We conclude, with an exploratory study in order to validate our approach.

O sistema cardiovascular está estrutural e funcionalmente disposto de modo “circular”. Situações de obstrução do fluxo sanguíneo determinam o aparecimento de mecanismos que visam suplantar tais interrupções e manter a circularidade íntegra. À nível molecular, o principal elemento envolvido nestes mecanismos é o Vascular Endothelial Growth Factor (VEGF). A expressão do VEGF quando há oclusão arterial está bem documentada, faltando elementos com relação à oclusão venosa. Neste estudo objetivamos verificar se a oclusão à nível arterial determina uma expressão do VEGF diferente daquela que ocorre se a oclusão acontecer à nível venoso. Para isso randomizamos dois grupos de ratos de experimentação. Em um grupo realizamos a oclusão da aorta infra-renal e em outro a oclusão da veia cava infra-renal. Posteriormente medimos a expressão do VEGF através da contagem do número de células marcadas imunoistoquimicamente no omento destes ratos. O resultado demonstrou que a expressão do VEGF, quando analisada pelo método proposto foi igual no grupo da oclusão venosa e no grupo da oclusão arterial. / The cardiovascular system is structurally and functionally circular. Situations in which there is obstruction to blood flow trigger mechanisms to bypass these blockages and maintenance the integrity of the circularity. At the molecular level the main factor involved is the Vascular Endothelial Growth Factor (VEGF). The VEGF expression associated with arterial occlusion is well documented but is lacking evidence when venous occlusion occurs. This study aimed to verify if the expression of VEGF when an occlusion occurs at venous level is the same or different from that caused at the arterial level. Two groups of rats were randomized by infra-renal aortic occlusion or inferior vena cava occlusion. VEGF was measured by counting the immunohistochemistry method marked cells at the omentum level. It was demonstrated that the VEGF expression is the same in the venous group obstruction as the arterial obstruction group.

O sistema cardiovascular está estrutural e funcionalmente disposto de modo “circular”. Situações de obstrução do fluxo sanguíneo determinam o aparecimento de mecanismos que visam suplantar tais interrupções e manter a circularidade íntegra. À nível molecular, o principal elemento envolvido nestes mecanismos é o Vascular Endothelial Growth Factor (VEGF). A expressão do VEGF quando há oclusão arterial está bem documentada, faltando elementos com relação à oclusão venosa. Neste estudo objetivamos verificar se a oclusão à nível arterial determina uma expressão do VEGF diferente daquela que ocorre se a oclusão acontecer à nível venoso. Para isso randomizamos dois grupos de ratos de experimentação. Em um grupo realizamos a oclusão da aorta infra-renal e em outro a oclusão da veia cava infra-renal. Posteriormente medimos a expressão do VEGF através da contagem do número de células marcadas imunoistoquimicamente no omento destes ratos. O resultado demonstrou que a expressão do VEGF, quando analisada pelo método proposto foi igual no grupo da oclusão venosa e no grupo da oclusão arterial. / The cardiovascular system is structurally and functionally circular. Situations in which there is obstruction to blood flow trigger mechanisms to bypass these blockages and maintenance the integrity of the circularity. At the molecular level the main factor involved is the Vascular Endothelial Growth Factor (VEGF). The VEGF expression associated with arterial occlusion is well documented but is lacking evidence when venous occlusion occurs. This study aimed to verify if the expression of VEGF when an occlusion occurs at venous level is the same or different from that caused at the arterial level. Two groups of rats were randomized by infra-renal aortic occlusion or inferior vena cava occlusion. VEGF was measured by counting the immunohistochemistry method marked cells at the omentum level. It was demonstrated that the VEGF expression is the same in the venous group obstruction as the arterial obstruction group.

Le coeur de cette thèse porte sur la modélisation géométrique et introduit une méthode robuste d'extraction de formes tubulaires à partir de nuages de points. Nous avons choisi de tester nos méthodes dans le contexte applicatif de la foresterie pour mettre en valeur la robustesse de nos algorithmes.Nos méthodes intègrent les normales aux points, il est donc nécessaire de les pré-calculer. Notre premier développement a alors consisté à présenter une méthode rapide d'estimation de normales. Pour ce faire nous avons approximé localement la géométrie du nuage de points en utilisant des "patchs" lisses dont la taille s'adapte à la complexité locale des nuages de points.Nos travaux se sont ensuite concentrés sur l’extraction robuste de formes tubulaires dans des nuages de points occlus, bruités et de densité inhomogène. Nous avons développé une variante de la transformée de Hough que nous avons couplé à une proposition de contours actifs indépendants de leur paramétrisation. Notre méthode a été validée en environnement forestier pour reconstruire des troncs d'arbre afin d'en relever les qualités par comparaison à des méthodes existantes.La reconstruction de troncs d'arbre ouvre d'autres questions dont la segmentation des arbres d'une placette forestière. Nous proposons également une méthode de segmentation pour isoler les différents objets d'un jeu de données.Durant nos travaux nous avons utilisé des approches de modélisation pour répondre à des questions géométriques, et nous les avons appliqué à des problématiques forestières. Il en résulte un pipeline de traitements cohérent qui, bien qu'illustré sur des données forestières, est applicable dans des contextes variés. / The core of this thesis concerns geometric modelling and introduces a fast and robust method for the extraction of tubular shapes from point clouds. We chose to test our method in the difficult applicative context of forestry in order to highlight the robustness of our algorithms.Our methods integrate normal vectors, thus they have to be pre-computed. Our first development consisted in the development of a fast normal estimation method on point cloud. To do so, we locally approximated the point cloud geometry using smooth "patches" of points which size adapts to the local complexity of the point cloud geometry.We then focused our work on the robust extraction of tubular shapes from dense, occluded, noisy point clouds suffering from non-homogeneous sampling density. We developed a variant of the Hough transform and combined this research with a new definition of parametrisation-invariant active contours. We validated our method in complex forest environments with the reconstruction of tree stems to emphasize its advantages and compare it to existing methods.Tree stem reconstruction also opens new perspectives halfway in between forestry and geometry such as the segmentation of trees from a forest plot. Therefore we propose a segmentation approach capable of isolating objects inside a point cloud.During our work we used modelling approaches to answer geometric questions and we applied our methods to forestry problems. Therefore, our studies result in a processing pipeline adapted to forest point cloud analyses, but the general geometric algorithms we propose can also be applied in various contexts.

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O sistema cardiovascular está estrutural e funcionalmente disposto de modo “circular”. Situações de obstrução do fluxo sanguíneo determinam o aparecimento de mecanismos que visam suplantar tais interrupções e manter a circularidade íntegra. À nível molecular, o principal elemento envolvido nestes mecanismos é o Vascular Endothelial Growth Factor (VEGF). A expressão do VEGF quando há oclusão arterial está bem documentada, faltando elementos com relação à oclusão venosa. Neste estudo objetivamos verificar se a oclusão à nível arterial determina uma expressão do VEGF diferente daquela que ocorre se a oclusão acontecer à nível venoso. Para isso randomizamos dois grupos de ratos de experimentação. Em um grupo realizamos a oclusão da aorta infra-renal e em outro a oclusão da veia cava infra-renal. Posteriormente medimos a expressão do VEGF através da contagem do número de células marcadas imunoistoquimicamente no omento destes ratos. O resultado demonstrou que a expressão do VEGF, quando analisada pelo método proposto foi igual no grupo da oclusão venosa e no grupo da oclusão arterial. / The cardiovascular system is structurally and functionally circular. Situations in which there is obstruction to blood flow trigger mechanisms to bypass these blockages and maintenance the integrity of the circularity. At the molecular level the main factor involved is the Vascular Endothelial Growth Factor (VEGF). The VEGF expression associated with arterial occlusion is well documented but is lacking evidence when venous occlusion occurs. This study aimed to verify if the expression of VEGF when an occlusion occurs at venous level is the same or different from that caused at the arterial level. Two groups of rats were randomized by infra-renal aortic occlusion or inferior vena cava occlusion. VEGF was measured by counting the immunohistochemistry method marked cells at the omentum level. It was demonstrated that the VEGF expression is the same in the venous group obstruction as the arterial obstruction group.

Devido às dificuldades encontradas na Medicina Veterinária com relação à circulação extracorpórea, despertou-se o interesse pela técnica de parada circulatória total (\"Inflow Occlusion\") para correção cirúrgica de algumas patologias cardíacas, principalmente estenose de valvas semi-lunares. O objetivo deste trabalho consistiu em comparar as possíveis alterações hemodinâmicas que podem ocorrer em cães submetidos à parada circulatória total através da técnica do \"Inflow Occlusion\" por diferentes períodos de tempo. Utilizou-se neste estudo, doze cães, subdivididos em dois grupos, sendo submetidos à parada circulatória total, por sete ou oito minutos. Realizou-se análise hemodinâmica durante quatro momentos do período transoperatório. Os parâmetros de oxigenação foram obtidos por meio da conjunção dos dados fornecidos pelo cateter de artéria pulmonar e pela análise hemogasométrica. Diferença estatisticamente significativa foi encontrada na comparação entre os grupos avaliados, cinco minutos após a restituição da circulação (momento M3), para a pressão arterial média (PAM) e para o índice de trabalho sistólico do ventrículo direito (ITSVD) e do ventrículo esquerdo (ITSVE). Ocorreram dois óbitos transoperatórios no grupo de animais submetidos à oito minutos de parada circulatória total, devido a fibrilação ventricular. Frente aos óbitos ocorridos, conclui-se que o \"Inflow Occlusion\" foi exequível em cães sadios por sete minutos, sendo contra-indicado para períodos de oito minutos. Entretanto, estudos clínicos envolvendo a técnica em questão, precisam ser realizados para que a referida técnica possa ser aplicada, seguramente, em animais portadores de disfunções cardiovasculares. / Because of difficulties related to extracorporeal circulation in Veterinary Medicine, more interest occurred about circulatory arrest trough \"Inflow Occlusion\" technique to correct surgically some cardiac pathologies, such as semilunar valves stenosis. The aim of this study was to compare possible hemodynamic alterations that can occur in dogs submitted to circulatory arrest using \"Inflow Occlusion\" technique for different periods of time. Twelve mongrel dogs were used in this study divided in two groups, each one submitted to seven or eight minutes of total circulatory arrest. Hemodynamic evaluation was realized during four moments on transoperatory period. Oxygenation parameters were obtained trough pulmonary artery catheter data and hemogasometric analysis. Statistical difference between groups were found on M3 moment, five minutes after circulatory arrest, for mean arterial pressure (MAP), right ventricular systolic stroke index (RVSSI) and left ventricular systolic stroke index (LVSSI). There were two transoperatory deaths on group B, because ventricular fibrillation. Because these deaths, we can say that \"Inflow Occlusion\" can be realized up to seven minutes on healthy dogs and is contra-indicated for periods of eight minutes. However, clinical studies should be performed in order to use this technique routinely with safe in dogs presenting cardiovascular abnormalities.

Background: To investigate whether vaccination against SARS-CoV-2 is associated with the onset of retinal vascular occlusive disease (RVOD). Methods: In this multicentre study, data from patients with central and branch retinal vein occlusion (CRVO and BRVO), central and branch retinal artery occlusion (CRAO and BRAO), and anterior ischaemic optic neuropathy (AION) were retrospectively collected during a 2-month index period (1 June–31 July 2021) according to a defined protocol. The relation to any previous vaccination was documented for the consecutive case series. Numbers of RVOD and COVID-19 vaccination were investigated in a case-by-case analysis. A case– control study using age- and sex-matched controls from the general population (study participants from the Gutenberg Health Study) and an adjusted conditional logistic regression analysis was conducted. Results: Four hundred and twenty-one subjects presenting during the index period (61 days) were enrolled: one hundred and twenty-one patients with CRVO, seventy-five with BRVO, fifty-six with CRAO, sixty-five with BRAO, and one hundred and four with AION. Three hundred and thirty-two (78.9%) patients had been vaccinated before the onset of RVOD. The vaccines given were BNT162b2/BioNTech/Pfizer (n = 221), followed by ChadOx1/AstraZeneca (n = 57), mRNA- 1273/Moderna (n = 21), and Ad26.COV2.S/Johnson & Johnson (n = 11; unknown n = 22). Our case–control analysis integrating population-based data from the GHS yielded no evidence of an increased risk after COVID-19 vaccination (OR = 0.93; 95% CI: 0.60–1.45, p = 0.75) in connection with a vaccination within a 4-week window. Conclusions: To date, there has been no evidence of any association between SARS-CoV-2 vaccination and a higher RVOD risk.