Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

Les engins autonomes suivent un plan de mission donné, parfois réactualisé par l'opérateur. La durée des missions et la limitation des communications poussent à développer des engins pourvus d'autonomie décisionnelle. Ce travail porte sur la replanification embarquée, illustrée sur une mission d'observation effectuée par un drone. Il vise à élaborer un planificateur de mission intégré dans une architecture embarquée. <br /><br />Le formalisme proposé décrit la sélection d'objectifs associés à des récompences variables et l'optimisation sous contraintes de leur réalisation dans le temps et l'espace. <br />Le cadre algorithmique, inspiré du A*, et des méthodes d'évaluation de coût, d'élagage et de rangement sont décrits. <br />Une architecture hybride hiérarchisée en 4 niveaux d'autonomie intègre le planificateur. <br />36 scénarios simulés sur 16 combinaisons de méthodes testent la partie alorithmique. L'analyse des résultats permet de dégager les méthodes obtenant les meilleurs compromis qualité/temps de calcul.

This thesis describes how a pipeline was obtained to reconstruct an urban environment from terrestrial laser scanning and photogrammetric 3D maps of Norrköping, visualized in first prison and real-time. Together with LIU University and the city planning office of Norrköping the project was carried out as a preliminary study to get an idea of how much work is needed and in what accuracy we can recreate a few buildings. The visualization is intended to demonstrate a new way of exploring the city in virtual reality as well as visualize the geometrical and textural details in a higher quality comparing to the 3D map that Municipality of Norrköping uses today. Before, the map has only been intended to be displayed from a bird’s eye view and has poor resolution from closer ranges. In order to improve the resolution, HDR photos were used to texture the laser scanned model and cover a particular area of the low res 3D map. This thesis will explain which method was used to process a point based environment for texturing and setting up an environment in Unreal using both the 3d map and the laser scanned model.

Polycrystalline geological materials are not normally single phase materials and commonly contain second phases which are known to influence the grain size and mechanical properties of bulk material. Despite the well documented significance of second phases, there are relatively few detailed systematic experimental studies of the effect of second phases on isostatic high temperature grain growth in geological materials. Grain growth is a process that is fundamental to our understanding of how rocks behave in the lower crust / upper mantle where grain size is considered to play an important role in the localization of deformation in addition to determining the strength of materials at these pressure and temperature conditions. Furthermore, the effect that the spatial distribution and grain size of the second phases have on the mechanical properties of rocks is generally acknowledged, but it is not well constrained. Spatial variation is particularly significant in geological systems where a strength contrast exists between phases. With these two things in mind, a two-part study is presented in which the influence of a pore second phase on the microstructural evolution of halite during grain growth (Part I), and the influence of a calcite second phase on the mechanical behaviour of two phase calcite + halite aggregates (Part II), is investigated. In Part I, high temperature (330 °-600 °C), high confining pressure (200 MPa) isostatic grain growth experiments were carried out on 38-125 μm reagent grade halite (99.5%+ NaCl) powder over durations of 10 secs up to 108 days. After hot-pressing, the halite displays a foam texture. Some porosity remained along the grain boundaries, the size and distribution of which appears to impact significantly on the resulting grain size, growth mechanism and kinetics of halite grain growth. Halite grain growth was found to be well described by the normal grain growth equation: d^(1/n)-d0^(1/n)=k0(t-t0)exp(-H/RT) where t is the duration of the growth period, t0 is the time at which normal growth begins, d is the grain size, d0 is the grain size at t0, k0 is a constant, H is the activation enthalpy for the growth controlling process, R is the universal gas constant,T is temperature and n is a growth constant. At 330 °-511 °C, the data is best described by n = 0.25 indicating growth controlled by surface diffusion around pores that lie on the grain boundaries. An activation enthalpy of 122±34 kJ/mol was obtained using the grain size data from these data sets. At 600 °C the data is best described by n = 0.5, suggesting that a transition to interface controlled growth takes place between 511 °C and 600 °C. To investigate the impact of porosity, the Zener parameter (Z = pore size/pore volume fraction) was determined for individual grains in 10 samples. A general trend of increasing with increasing halite grain size is observed, indicating pore elimination keeps pace with pore accumulation in the growing grains. In some samples, the largest grains display a decrease in the Zener parameter corresponding with an increase in pore volume fraction. These grains are interpreted as having experienced a short-lived, abnormal growth phase shortly after t0 during which pore accumulation outpaced pore elimination. A model of pore controlled grain growth is proposed with a view to explaining these observations. In Part II, calcite + halite aggregates of constant volume fraction (0.60 calcite : 0.40 halite) and varying calcite clast size (6 μm 361 μm) were axially deformed to <1% bulk strain at room temperature in a neutron diffraction beamline. Elastic strain and stress in each phase was determined as a function of load from the neutron diffraction data. The strain (and stress) behaviour correlates well with the microstructural parameters: 1) halite mean free path and 2) calcite contiguity. Both phases behaved elastically up to aggregate axial stresses of 20-37 MPa, above these stresses the halite yielded plastically while the calcite remained elastic. Once yielding began, the rate of enhanced load transfer from halite to calcite with increasing applied load decreased with halite mean free path and increased calcite with contiguity. A Hall-Petch relationship between halite mean free path and aggregate yield stress was observed.