A method for modifying segmented human voxel models is depicted. The method is a practical approach to set up voxel models for dose calculations in medical physics. It could also be applied in other fields requiring human voxel models. The basic strategy of the method is: 1. Generate triangulated surfaces from voxel representations of the objects (organs, bones, or tissues) of a segmented human voxel model. 2. Perform surface deformations and/or rearrangements. 3. Reconstruct voxel representations from the triangulated surfaces and put them back into the segmented human voxel model. The voxel volume of the modified organs can be adjusted up to the volume of half a voxel. The practicability of the method is demonstrated by means of the spleen of a leukaemia patient. / Es wird eine praktische Methode zum Verändern von segmentierten menschlichen Voxel-Modellen dargelegt. Die Methode kann in der Medizinphysik im Zusammenhang mit Strahlendosisberechnungen angewendet werden. Sie kann jedoch auch in anderen Gebieten benutzt werden, bei denen menschliche Voxel-Modelle zur Anwendung kommen. Die grundlegende Strategie der Methode besteht aus den folgenden Schritten: 1. Erzeugung triangulierter Oberflächen aus Objekten (Organen, Knochen, Geweben) eines segmentierten menschlichen Voxel-Modells. 2. Durchführung interaktiver Oberflächendeformationen und/oder Verschiebungen. 3. Re-Überführung der triangulierten Oberflächen in Voxel-Darstellungen der Organe und Rückschreibung in das segmentierte menschliche Voxel-Modell. Das Voxel-Volumen der modifizierten Organe kann mindestens bis auf ein halbes Voxel genau eingestellt werden. Die Anwendbarkeit der Methode wird anhand der Milz einer Leukämie-Patientin demonstriert.

Concepción is the most active composite volcano in Nicaragua, and is located on Ometepe Island, within Lake Nicaragua. Moderate to small volcanic explosions with a volcanic explosivity index (VEI) of 1-2 have been characteristic of this volcano during the last four decades. Although its current activity is not violent, its volcanic deposits reveal stages of violent activity involving Plinian and sub-Plinian eruptions that deposited vast amounts of volcanic tephra in the Atlantic Ocean. These observations, together with the 31,000 people living on the island, make Concepción volcano an important target for volcanological research. My research focuses on the investigation of the stability of the volcano edifice of Concepción, using geophysical data such as gravity, geodetic global positioning system (GPS), sulphur dioxide (SO2) flux, real-time seismic amplitude (RSAM), and satellite remotely-sensed data. The integration of these data sets provides information about the short-term behavior of Concepción, and some insights into the volcano's long-term behavior. This study has provided, for the first time, information about the shallow dynamics of Concepción on time scales of days to weeks. I furnish evidence that this volcano is not gravitationally spreading in a continuous fashion as previously thought, that its bulk average density is comparable to that of a pile of gravel, that the volcano edifice is composed of two major distinctive lithologies, that the deformation field around the volcano is recoverable in a matter of days, and that the deformation source is located in the shallow crust. This source is also degassing through the relatively open magmatic conduit. There are, however, several remaining questions. Although the volcano is not spreading continuously there is the possibility that gravitational spreading may be taking place in a stick-slip fashion. This has important implications for slope stability of the volcano, and the associated hazards. The factors influencing the long term slope stability of the volcano are still not fully resolved, but internal volcanic processes and anthropogenic disturbances appear to be the major factors.

The Surface Deformation Prediction System (SDPS) program has been developed as an engineering tool for the prediction of subsidence deformation indices through the implementation of an influence function. SDPS provides reliable predictions of mining induced surface displacements, strains, and tilt for varying surface topography. One of the key aspects in obtaining reliable ground deformation prediction is the determination of the edge effect offset. The value assigned to the edge effect corresponds to a virtual offsetting of boundary lines delineating the extracted panel to allow for roof cantilevering over the mined out area. The objective of this thesis is to describe the methods implemented in updating the edge effect offset algorithm within SDPS. Using known geometric equations, the newly developed algorithm provides a more robust calculation of the offset boundary line of the extracted panel for simplistic and complex mining geometries. Assuming that an extracted panel is represented by a closed polyline, the new edge offset algorithm calculates a polyline offset into the extracted panel by the user defined edge effect offset distance. Surface deformations are then calculated using this adjusted panel geometry. The MATLAB® program was utilized for development and testing of the new edge effect offset feature.

A storage and enhanced coalbed methane (CO2-ECBM) test will store up to 20,000 tons of carbon dioxide in a stacked coal reservoir in southwest Virginia. The test involves two phases of CO2 injection operations. Phase I was conducted from July 2, 2015 to April 15, 2016, and injected a total of 10, 601 tons of CO2. After a reservoir soaking period of seven months, Phase II is scheduled to begin Fall 2016. The design of the monitoring program for the test considered several site-specific factors, including a unique reservoir geometry, challenging surface terrain, simultaneous CBM production activities which complicate the ability to attribute signals to sources. A multi-scale approach to the monitoring design incorporated technologies deployed over different, overlapping spatial and temporal scales selected for the monitoring program include dedicated observation wells, CO2 injection operations monitoring, reservoir pressure and temperature monitoring, gas and formation water composition from offset wells tracer studies, borehole liquid level measurement, microseismic monitoring, surface deformation measurement, and various well logs and tests. Integrated interpretations of monitoring results from Phase I of the test have characterized enhanced permeability, geomechanical variation with depth, and dynamic reservoir injectivity. Results have also led to the development of recommended injection strategy for CO2-ECBM operations. The work presented here describes the development of the monitoring program, including design considerations and rationales for selected technologies, and presents monitoring results and interpretations from Phase I of the test. / Ph. D.

En animation de personnages 3D, la déformation de surface, ou skinning, est une étape cruciale. Son rôle est de déformer la représentation surfacique d'un personnage pour permettre son rendu dans une succession de poses spécifiées par un animateur. La plausibilité et la qualité visuelle du résultat dépendent directement de la méthode de skinning choisie. Sa rapidité d'exécution et sa simplicité d'utilisation sont également à prendre en compte pour rendre possible son usage interactif lors des sessions de production des artistes 3D. Les différentes méthodes de skinning actuelles se divisent en trois catégories. Les méthodes géométriques sont rapides et simples d'utilisation, mais leur résultats manquent de plausibilité. Les approches s'appuyant sur des exemples produisent des résultats réalistes, elles nécessitent en revanche une base de données d'exemples volumineuse, et le contrôle de leur résultat est fastidieux. Enfin, les algorithmes de simulation physique sont capables de modéliser les phénomènes dynamiques les plus complexes au prix d'un temps de calcul souvent prohibitif pour une utilisation interactive. Les travaux décrits dans cette thèse s'appuient sur Implicit Skinning, une méthode géométrique corrective utilisant une représentation implicite des surfaces, qui permet de résoudre de nombreux problèmes rencontrés avec les méthodes géométriques classiques, tout en gardant des performances permettant son usage interactif. La contribution principale de ces travaux est un modèle d'animation qui prend en compte les effets des muscles des personnages et de leur interactions avec d'autres éléments anatomiques, tout en bénéficiant des avantages apportés par Implicit Skinning. Les muscles sont représentés par une surface d'extrusion le long d'axes centraux. Les axes des muscles sont contrôlés par une méthode de simulation physique simplifiée. Cette représentation permet de modéliser les collisions des muscles entre eux et avec les os, d'introduire des effets dynamiques tels que rebonds et secousses, tout en garantissant la conservation du volume, afin de représenter le comportement réel des muscles. Ce modèle produit des déformations plus plausibles et dynamiques que les méthodes géométriques de l'état de l'art, tout en conservant des performances suffisantes pour permettre son usage dans une session d'édition interactive. Elle offre de plus aux infographistes un contrôle intuitif sur la forme des muscles pour que les déformations obtenues se conforment à leur vision artistique. / Surface deformation, or skinning is a crucial step in 3D character animation. Its role is to deform the surface representation of a character to be rendered in the succession of poses specified by an animator. The quality and plausiblity of the displayed results directly depends on the properties of the skinning method. However, speed and simplicity are also important criteria to enable their use in interactive editing sessions. Current skinning methods can be divided in three categories. Geometric methods are fast and simple to use, but their results lack plausibility. Example-based approaches produce realistic results, yet they require a large database of examples while remaining tedious to edit. Finally, physical simulations can model the most complex dynamical phenomena, but at a very high computational cost, making their interactive use impractical. The work presented in this thesis are based on, Implicit Skinning, is a corrective geometric approach using implicit surfaces to solve many issues of standard geometric skinning methods, while remaining fast enough for interactive use. The main contribution of this work is an animation model that adds anatomical plausibility to a character by representing muscle deformations and their interactions with other anatomical features, while benefiting from the advantages of Implicit Skinning. Muscles are represented by an extrusion surface along a central axis. These axes are driven by a simplified physics simulation method, introducing dynamic effects, such as jiggling. The muscle model guarantees volume conservation, a property of real-life muscles. This model adds plausibility and dynamics lacking in state-of-the-art geometric methods at a moderate computational cost, which enables its interactive use. In addition, it offers intuitive shape control to animators, enabling them to match the results with their artistic vision.

A method for modifying segmented human voxel models is depicted. The method is a practical approach to set up voxel models for dose calculations in medical physics. It could also be applied in other fields requiring human voxel models. The basic strategy of the method is: 1. Generate triangulated surfaces from voxel representations of the objects (organs, bones, or tissues) of a segmented human voxel model. 2. Perform surface deformations and/or rearrangements. 3. Reconstruct voxel representations from the triangulated surfaces and put them back into the segmented human voxel model. The voxel volume of the modified organs can be adjusted up to the volume of half a voxel. The practicability of the method is demonstrated by means of the spleen of a leukaemia patient. / Es wird eine praktische Methode zum Verändern von segmentierten menschlichen Voxel-Modellen dargelegt. Die Methode kann in der Medizinphysik im Zusammenhang mit Strahlendosisberechnungen angewendet werden. Sie kann jedoch auch in anderen Gebieten benutzt werden, bei denen menschliche Voxel-Modelle zur Anwendung kommen. Die grundlegende Strategie der Methode besteht aus den folgenden Schritten: 1. Erzeugung triangulierter Oberflächen aus Objekten (Organen, Knochen, Geweben) eines segmentierten menschlichen Voxel-Modells. 2. Durchführung interaktiver Oberflächendeformationen und/oder Verschiebungen. 3. Re-Überführung der triangulierten Oberflächen in Voxel-Darstellungen der Organe und Rückschreibung in das segmentierte menschliche Voxel-Modell. Das Voxel-Volumen der modifizierten Organe kann mindestens bis auf ein halbes Voxel genau eingestellt werden. Die Anwendbarkeit der Methode wird anhand der Milz einer Leukämie-Patientin demonstriert.

Dans cette thèse, nous nous sommes intéressés à la statique et la dynamique du mouillage de gouttes d’eau sur des substrats mous tels que des gels, encore connu sous le nom d’élastomouillage. Pour ce faire, nous avons d'abord développé une méthode quantitative de visualisation par strioscopie permettant de mesurer la déformation de la surface d'un film de gel transparent avec une précision élevée. Nous montrons que la déformation superficielle de films mous de silicone (PDMS) dépend de la taille des gouttelettes déposées ainsi que de l'épaisseur et de l’élasticité de ces films. Nous avons construit un modèle basé sur la théorie de l'élasticité linéaire tenant compte de la tension superficielle des gels qui prédit bien la forme et l’amplitude de la déformation de surface. Nous apportons aussi la preuve expérimentale et l'analyse théorique de l’importance de l'hystérèse de l’angle de contact dans la description de la déformation en démontrant que la force tangentielle due à la tension superficielle entre liquide et vapeur à la ligne de contact, souvent négligé, contrôle la déformation de la surface. La dynamique de mouillage est étudiée en dégonflant des gouttelettes sur des films de PDMS avec une épaisseur bien contrôlée. Il est démontré que la dissipation d'énergie dans le gel dépend fortement de l'épaisseur lorsque cette dernière est inférieure à 100 μm). L'effet de freinage viscoélastique et l'effet d'épaisseur sont bien rationalisés avec un modèle basé sur la viscoélasticité linéaire et une simple loi l'échelle qui tient compte de l'effet d'épaisseur capture très bien nos expériences. Enfin, nous démontrons que nous pouvons dériver et guider les gouttelettes en mouvement avec la conception de surfaces couvertes de couches de gels ayant des gradients d'épaisseur. / In this thesis, we aim at obtaining a better understanding of the statics and dynamics of the wetting of liquids on soft gels, otherwise known as elastowetting. First, we develop a quantitative Schlieren optics to measure the surface deformation of a transparent gel film with a high precision over large areas in real time. The long-range surface deformation of soft PDMS films is found to be dependent on the sessile droplet size, and the thickness and elasticity of the soft films. We build a model based on linear elasticity theory with the integration of the surface tension of soft materials that predicts the long-range surface deformation in excellent agreement with the data. We also bring the experimental proof and theoretical analysis of the importance of contact angle hysteresis in the description of the deformation of the surface of the gel. We demonstrate that the tangential component of the liquid-vapor surface tension at the contact line, whose contribution are often neglected, significantly affects the surface deformation. Wetting dynamics is investigated by deflating droplets on PDMS films with well-controlled thickness. It is shown that energy dissipation in the soft gel depends on the thickness when the latter is smaller than 100 μm. The viscoelastic braking effect and the thickness effect are both well rationalized with a model based on the theory of linear viscoelasticity and a simple scaling law accounting for the thickness effect captures very well our experiments. Finally, we demonstrate that we are able to guide moving droplets with coatings having a gradient of their thickness.

The end-member types of shallow magmatic intrusions comprise cone sheets and dykes. These propagate from their source magma chamber towards the Earth’s surface. The propagation of magma within the shallow part of the volcano plumbing system produces surface deformation and seismicity, signs of volcanic unrest. Studying surface displacement using GPS and InSAR, geodetic modelling, fitting modelled data to real displacements, and inversion is regularly used to understand the processes in the subsurface. There is no possibility in nature to validate the assumptions of these models. However, using analogue modelling, it is possible to reproduce cone sheets and dykes in a controlled environment and study the associated surface deformation. This thesis tests the hypothesis that the two end-member types of magmatic sheet intrusions produce specific patterns of surface deformation. The analogue model surface is documented using two different monitoring setups: moiré monitoring and photogrammetry. The moiré method (dataset 1) consists of 43 experiments, 19 of which were dykes, 22 were cone sheets, and 2 were classified as hybrids. Photo- grammetry (dataset 2) was applied in 8 experiments, 3 of which produced cone sheets and 5 dykes. Dataset 1 successfully identified surface deformation patterns specific to the two intrusion types. Cone sheets develop in a gradual linear fashion, while the dykes exhibit a two-phase behaviour. The first phase shows little deformation until about halfway through the experiment duration when rapid deformation starts to occur. The point of maximum uplift, in both intrusion types, indicates the area of eruption from an early stage. Dataset 2 primarily evaluated the benefits of using the photogrammetric method. It successfully resolved horizontal components of displacement making it possible to study brittle defor- mation. As Dataset 2 consists of a limited amount of experiments, the results cannot be considered conclusive. However, they indicate that characteristic patterns of brittle deformation exist for the two types. Future improvements in this field include studying effects of topography and anisotropy on the surface deformation of the analogue models. Improvements in temporal and spatial resolution in the monitoring methods used to study surface displacement in nature is needed to perform analyses, similar to the ones presented here, on real surface deformation. The misfit of the surface deformation seen in numerical models compared to analogue models indicate that sheet intrusion propagation is not yet fully understood. / När magma rör sig från magmakammare mot jordytan i den ytliga delen av det underjordiska system av magma som finns under vulkaner, bildas ytdeformation. Genom att studera ytdeformationen med hjälp av GPS och InSAR samt numerisk modellering försöker forskare förstå dessa underjordiska processer för att förutspå framtida utbrott. Dessvärre finns ingen möjlighet att undersöka huruvida dessa numeriska modeller faktiskt överensstämmer med naturen. I gamla utdöda vulkaner som eroderats ner kan man se vulkanens inre där det finns stelnade, magmafyllda sprickor, så kallade gångar. Tyvärr ger detta dock ingen inblick i hur gångarnas bildning återspeglades i ytan. Detta kan man undersöka med hjälp av analoga modeller där det är möjligt att skapa likartade intrusioner i en kontrollerad labb-miljö och studera den tillhörande ytdeformationen. Denna avhandling undersöker hypotesen att de två huvudsakliga typerna av ytliga magmatiska gångar skapar specifika identifierbara mönster av ytdeformation. Detta testas genom att dokumentera den analoga modellens yta alltjämt som intrusionerna bildas med hjälp av två olika övervaknings- metoder. Den första metoden lyckades identifiera mönster som är specifika för de två olika typerna. Den högsta punkten på den deformerade ytan kan användas för att förutspå den plats där framtida utbrott kommer att ske i båda typerna. Den andra metoden lyckades urskilja dem horisontella komponenterna av förskjutning som gör det möjligt att studera den spröda deformation som utvecklas på ytan. Resultaten tyder på att karakteristiska mönster av spröd deformation existerar för de två typerna. För att förbättra de analoga modellerna måste man undersöka hur en mer topografiskt varierad yta påverkar den bildade deformation samt en skorpa som inte är helt homogen. Vid jämförelse mellan numeriska modeller och analoga modeller sågs en stor skillnad som tyder på att vi ännu inte förstår hur magma rör sig genom jordskorpan. Framtida användning av analyserna presenterade i denna avhandling kräver en förbättring av upplösningen på systemen som används till vulkanövervakning i naturen.

Biometric identification systems have several distinct advantages over other authentication technologies, such as passwords, in reliably recognising individuals. Iris based recognition is one such biometric recognition system. Unlike other biometrics such as fingerprints or face images, the distinct aspect of the iris comes from its randomly distributed features. The patterns of these randomly distributed features on the iris have been proved to be fixed in a person's lifetime, and are stable over time for healthy eyes except for the distortions caused by the constriction and dilation of the pupil. The distortion of the iris pattern caused by pupillary activity, which is mainly due changes in ambient lighting conditions, can be significant. One important question that arises from this is: How closely do two different iris images of the same person, taken at different times using different cameras, in different environments, and under different lighting conditions, agree with each other? It is also problematic for iris recognition systems to correctly identify a person when his/her pupil size is very different from the person's iris images, used at the time of constructing the system's data-base. To date, researchers in the field of iris recognition have made attempts to address this problem, with varying degrees of success. However, there is still a need to conduct in-depth investigations into this matter in order to arrive at more reliable solutions. It is therefore necessary to study the behaviour of iris surface deformation caused by the change of lighting conditions. In this thesis, a study of the physiological behaviour of pupil size variation under different normal indoor lighting conditions (100 lux ~ 1,200 lux) and brightness levels is presented. The thesis also presents the results of applying Elastic Graph Matching (EGM) tracking techniques to study the mechanisms of iris surface deformation. A study of the pupil size variation under different normal indoor lighting conditions was conducted. The study showed that the behaviour of the pupil size can be significantly different from one person to another under the same lighting conditions. There was no evidence from this study to show that the exact pupil sizes of an individual can be determined at a given illumination level. However, the range of pupil sizes can be estimated for a range of specific lighting conditions. The range of average pupil sizes under normal indoor lighting found was between 3 mm and 4 mm. One of the advantages of using EGM for iris surface deformation tracking is that it incorporates the benefit of the use of Gabor wavelets to encode the iris features for tracking. The tracking results showed that the radial stretch of the iris surface is nonlinear. However, the amount of extension of iris surface at any point on the iris during the stretch is approximately linear. The analyses of the tracking results also showed that the behaviour of iris surface deformation is different from one person to another. This implies that a generalised iris surface deformation model cannot be established for personal identification. However, a deformation model can be established for every individual based on their analysis result, which can be useful for personal verification using the iris. Therefore, analysis of the tracking results of each individual was used to model iris surface deformations for that individual. The model was able to estimate the movement of a point on the iris surface at a particular pupil size. This makes it possible to estimate and construct the 2D deformed iris image of a desired pupil size from a given iris image of another different pupil size. The estimated deformed iris images were compared with their actual images for similarity, using an intensitybased (zero mean normalised cross-correlation). The result shows that 86% of the comparisons have over 65% similarity between the estimated and actual iris image. Preliminary tests of the estimated deformed iris images using an open-source iris recognition algorithm have showed an improved personal verification performance. The studies presented in this thesis were conducted using a very small sample of iris images and therefore should not be generalised, before further investigations are conducted.

Laser welding is commonly used in the automotive-, steel- and aerospace industry. It is a highly non-linear and coupled process where the weld geometry is strongly affected by the flow pattern in the melt pool. Experimental observations are challenging since the melt pool and melt flow below the surface are not yet accessible during welding. Improved process control would allow maintaining, or improving, product quality with less material and contribute further to sustainability by reducing production errors. Numerical modelling with Computational Fluid Dynamics, CFD, provides complementary understanding with access to process properties that are not yet reachable with experimental observation. However, the existing numerical models lack predictability when considering the weld shape. The work presented here is the development of a model for conduction laser welding. The solver upon which the model is based is first described in detail. Then different validation cases are applied in order to test specific parts of the physics implemented. Two cases focus on thermocapillary convection in two-phase and three-phase flows with surface deformation. Finally, a third case considers the melt pool flow during conduction mode welding.It is concluded that the convection of fusion enthalpy, which was neglected in former studies, should be included in the model. The implementation of the thermo capillary force is recommended to be consistent with the other surface forces to avoid unphysical solution. Free surface oscillations, known from experimental observations, are also computed numerically. However, further investigation is needed to check that these oscillations are not disturbed b ynumerical oscillations.