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

The airline industry is crucial to economic growth and the number of passengers is expected to increase by approximately 250 million from 2017 to 2018. IATA believes it is imperative to increase airline efficiency to maintain sustainability. Passenger boarding is known to constitute 60% of airplane turnaround time, identifying this step as rate determining. In this study, we investigate passenger boarding strategies utilized by airline companies and strategies simulated by existing literature. We propose more efficient passenger boarding methods for the Airbus A320/ Boeing 737 and Airbus A380-800/ Boeing 777-300ER airline classes. We use GNU Octave to construct a cellular automaton model that operates on the interaction of a 2-dimensional matrix, representing passenger attributes, and a 4-dimensional matrix, representing the cells of the airplane in consideration. We consider row interferences, aisle interferences, luggage stow away time, and general passenger delays. We find that boarding strategies which minimize passenger interferences are the most efficient for both airline classes. Interestingly, some boarding strategies for the Airbus A320/ Boeing 737 are more efficient when boarding at 30 passengers/ min instead of 60 passengers/ min. However, the Airbus A380-800/ Boeing 777-300ER shows slower boarding rates for any boarding frequency less than 60 passengers/ min, suggesting the size of the airplane layout determines sensitivity to boarding frequency. With the Airbus A380-800/ Boeing 777-300ER having limited documentation, we define and propose new boarding strategies, OBFOIZ and OBFOISA, that improve on the passenger boarding times in the existing literature for this double-aisled airplane. / Thesis / Master of Science (MSc) / The airline industry is crucial to economic growth and the number of passengers is increasing every year, reaching increases of 250 million. In light of this, the International Air Transport Association believes it is imperative to increase airline efficiency. Since airplanes generate revenue while they are in the air, we look to minimize the time they are on the tarmac, also known as airplane turnaround time. Passenger boarding has shown to constitute 60% of airplane turnaround time, identifying this step as a bottleneck. In this study, we investigate passenger boarding strategies utilized by airline companies and documented by existing literature. We then propose more efficient passenger boarding methods for the Airbus A320/ Boeing 737 and Airbus A380-800/ Boeing 777-300ER airline classes. With the Airbus A380-800/ Boeing 777-300ER having limited documentation, we define and propose new boarding strategies that improve the passenger boarding time.

Le travail de cette thèse s’inscrit dans le cadre du développement du programme S.E.T.U.P. (Simulations Expérimentale et Théorique Utiles à la planétologie) dont l’objectif est d’effectuer des simulations représentatives de l’atmosphère de Titan et de déterminer les processus physico-chimiques qui y sont impliqués. Pour ce faire, un dispositif expérimental combine deux types de dépôts d’énergie (électrons et photons) représentatifs des processus de dissociation des molécules N2 et CH4 qui composent majoritairement l’atmosphère de Titan. De plus, une technique d’analyse par spectroscopie laser doit permettre d’identifier et de quantifier des produits et donc de suivre l’évolution du mélange réactionnel in situ en temps réel.La méthodologie adoptée pour la mise en œuvre des expériences de simulations a été de caractériser l’ensemble des étapes depuis les sources énergétiques jusqu’à l’analyse des produits et de développer les outils de modélisation nécessaires à l’interprétation des expériences.Dans un premier temps, il s’est agit de mieux caractériser les deux types de photolyse du méthane envisagés. En effet, il est prévu d’utiliser soit une lampe UV délivrant un rayonnement à Lyman-α (121,6 nm) soit un laser excimère KrF pulsé délivrant un rayonnement à 248 nm. Ce dernier doit en effet permettre des études cinétiques concernant les espèces à courte durée de vie. Des expériences d’irradiation de CH4 et d’un mélange N2/CH4 aux deux longueurs d’onde ont été menées puis simulées grâce à un modèle 0D.L’analyse fine des résultats issus des irradiations de CH4 à Lyman-α montre que des travaux complémentaires sont nécessaires pour comprendre les différences entre les expériences et le modèle chimique. En particulier, une caractérisation de l’émission de la lampe s’est avérée indispensable et a été réalisée afin d’améliorer la compréhension de la chimie mise en jeu. Les résultats obtenus lors de l’irradiation à 248 nm suggèrent que la source laser utilisée pourrait provoquer l’ionisation de CH4 et induire une chimie ionique qui n’était pas envisagée au départ. Ce type d’irradiation pourrait se révéler intéressant pour étudier les processus ionosphériques de l’atmosphère de Titan. En revanche, cette source doit être abandonnée pour l’étude de la chimie des neutres. Une source pulsée à Lyman-α devra être développée.Dans un deuxième temps, trois types d’expériences préliminaires de simulations de l’atmosphère de Titan ont été effectuées. Afin de mieux comprendre l’importance relative de chaque source énergétique, des expériences dites de « plasma » où N2 et CH4 sont dissociés simultanément dans un plasma crée par décharge microonde, ont tout d’abord été menées. Ensuite, des expériences dites de « post-décharge » où CH4 est introduit dans l’enceinte après la dissociation de N2 par plasma, ont été conduites. Et enfin, des expériences dites de « couplage », censées mieux représenter les processus de l’atmosphère de Titan où CH4, toujours introduit en post-décharge, est cette fois photodissocié à Lyman-α, ont été réalisées.Lors des expériences « plasma », dix composés sont identifiés : HCN, NH3, HC3N, C2H2, C2H4, C2H6, C3H4, C4H2, HC5N et C6H2. Leur abondance est globalement en bon accord avec celle déterminée par les observations de la haute atmosphère de Titan dans la zone comprise entre 900 et 1200 km d’altitude validant ainsi le module plasma du dispositif. Lors des expériences « post-décharge » et « couplage », seuls les composés azotés HCN et NH3 sont formés et cela indépendamment du fait que le CH4 subisse ou pas une irradiation UV. Ce résultat s’explique par le fait que le taux de photodissociation du CH4 se révèle très inférieur à la dissociation de N2 par les électrons, ce qui empêche une complexification chimique des hydrocarbures dans les simulations. Il s’avère donc indispensable de modifier la source de rayonnement à Lyman-α afin d’être beaucoup plus efficace en terme de flux.Les résultats acquis grâce à cette méthodologie « étape par étape » ont permis de mettre en évidence les paramètres qu’il faut impérativement maîtriser pour la mise en œuvre de simulations pertinentes de l’atmosphère de Titan. Ils définissent aussi l’orientation des futurs développements du projet SETUP / The work of this thesis enters in the frame of the development of a scientific program named S.E.T.U.P. (a french acronym for Theoretical and Experimental Simulations Useful for Planetology) whose objective is to perform representative laboratory simulations of Titan's atmosphere. The study seeks to highlight the mechanisms responsible for the evolution of region of the stratosphere where a neutral chemistry is involved. With this aim, an experimental device has been built. The coupled N2/CH4 chemistry is initiated, in a flow reactor, by both electrons (microwave plasma discharge) and photons (irradiation by a continuous lamp or a excimer pulsed laser). In addition, laser spectroscopy technique is used in order to identify and quantify the products allowing the in situ analysis of the evolution of the resulting gas phase. First, I have studied methane photolysis at two different wavelengths. Indeed, in simulation experiments, methane photo-dissociation could involve photons either at 121.6 nm (Lyman-α) or at 248 nm respectively delivered by a H2/He lamp or a pulsed KrF excimer laser (this latter should enable kinetic studies of transient species). Irradiation experiments of pure CH4 and of N2/CH4 mixtures at both wavelengths have been conducted; afterwards, they have been simulated by a 0D photochemical model. Results obtained from the CH4 irradiations at Lyman-α indicate that additional works were needed to understand the differences between experimental and theoretical profiles for all the species formed during irradiation. In particular, the emission spectrum of the UV lamp has to be recorded, then, it turns out that its particular shape, as the intensity is not centered at but is spread in a wide range of wavelengths, has to be taken-Lyman- into account in the model. The latter has thus be improved allowing to better reconcile experimental and theoretical data. Results obtained for the 248 nm irradiations suggest that CH4 is not only dissociated but also ionized. Therefore, although this radiation could be interesting to study ionospheric processes held in Titan’s atmosphere, it is definitely not suitable to study the neutral chemistry we are interested in, therefore, the use of a laser delivering, this time, a radiation should be then considered if we want to pursue with -Lyman- fast kinetic studies. Secondly, I have implemented three types of preliminary experimental simulations of Titan's atmosphere: i) N2/CH4 discharge simulation experiments ii) N2/CH4 post-discharge simulation experiments, i.e. CH4 is introduced downstream of the flowing afterglow of a pure N2 discharge iii) coupled simulation simulations i.e. CH4, introduced downstream of the flowing afterglow of pure N2 microwave discharge is irradiated by a H2/He lamp (121.6 nm). Ex-situ qualitative and quantitative analysis of the resulting gas mixture recovered in a cold trap has been performed, for the first time, by IRTF spectroscopy. In N2/CH4 discharge experiments, more or less similar to those commonly conducted (the difference lies in the type of plasma used), the obtained products are HCN, NH3, HC3N, HC5N, C2H2, C2H4, C2H6, C3H4, C4H2 and C6H2 with abundances compatible with those retrieved from observations of Titan’s high atmosphere in the range between 900 to 1200 km. More surprisingly, in the N2/CH4 post discharges experiments, only HCN and NH3 are observed and this regardless the fact that methane is photolyzed or not. This result is explained by the fact that CH4’s photodissociation appears to be less efficient than N2’s dissociation in the plasma preventing the formation of hydrocarbons. It is therefore necessary to increase the radiation flux of radiation. The use of a radiation would allow reaching thislaser delivering a Lyman- objective. The results obtained with this “step by step” methodology helped to highlight the essential parameters that we have to master for the implementation of relevant experimental simulations of Titan's atmosphere. They also define the direction for the future developments of SETUP project

La tendance dans la conception de cartes électroniques imprimées est de remplacer les traditionnels bus parallèles par des liens série rapides dont le débit peut atteindre plusieurs dizaines de Gigabit par seconde (Gbps). Cette thèse proposée par THALES Communications & Security en collaboration avec le laboratoire SATIE de l'ENS de Cachan a pour objectif de définir une approche adaptée au traitement des problèmes de liens multi-gigahertz, de manière à garantir le fonctionnement d’une carte numérique complexe (multicouches, haute densité d'intégration, ...) sans qu’une phase de prototypage ne soit nécessaire. Après un état de l’art, ce travail s’est organisé en trois parties : La première partie porte sur l'étude du canal de propagation. La décomposition spectrale des liens multi-gigabits couvrant plusieurs gigahertz voir plusieurs dizaines de gigahertz montre la nécessité d'employer des logiciels de simulations spécifiques au domaine des hyperfréquences. Une évaluation de certains solveurs électromagnétiques 3D parmi les plus récents a été réalisée afin d'extraire les paramètres S du canal de propagation de façon précise et rapide a partir des informations issues des logiciels de CAO utilisés à THALES. La seconde partie traite de la prise en compte des émetteurs, des récepteurs et des traitements numériques associés dans la simulation afin de réaliser des calculs de diagrammes de l'œil, de taux d’erreurs binaires (BER) et de jitter. L’utilisation de la norme IBIS-AMI, très récente, et la comparaison des performances aves d’autres outils, tel que HSPICE, a demandé l'évaluation de simulateurs circuit de dernière génération. Cette étape a été réalisée en étroite collaboration avec les éditeurs des logiciels car certains outils ne sont pas suffisamment matures pour s'inscrire dans un flot global de conception. Enfin, la chaîne de simulation complète ayant été validée par la mesure, nous avons effectué une analyse approfondie des différentes composantes du jitter en fonction des phénomènes physiques plus ou moins destructeurs pour la qualité du signal. Cela nous a ensuite permis d’établir les règles et la méthodologie de conception, en tenant compte des marges allouées à partir des résultats de l’analyse du jitter. / The designers of Printed Circuit Board (named “board” below) tend to use more and more multi-gigabit serial links rather than traditional parallel buses. It enables to push back the density limitations and to increase embedded functionalities of the board. This thesis is the result of collaboration with THALES Communications & Security and the SATIE laboratory of ENS Cachan. The goal of the thesis was to define an approach dedicated to the study of Multi-GigaHertz (MGH) signals in order to assure that digital complex boards work without costly multiple prototype designs. After an inventory of the state of the arts, this work was conducted in three parts: The firt part relates to the study of the propagation channel. The spectral power distribution of the multi-gigabit links ranges from DC to several dozens of gigahertz, it is the reason why specific simulation softwares usually used in the hyper-frequency field have to be used A benchmark of several most recent 3D ElectroMagnetic (EM) solvers has been achieved in order to quickly and accurately extract the S Parameter matrix of the propagation channel thanks to information from CAO softwares used in THALES The second part consisted to take into account the transmitters, the receivers and the digital treatments associated in the circuit simulation in order to calculate eye diagrams, Bit Error Rate (BER) and Jitter separation. The benchmark of the latest generation of channel simulators was needed for the use of the recent norm IBIS-AMI and the comparison of the performances with other tools, such as HSPICE. This step has been led in close collaboration with the simulation software suppliers because some tools are not mature enough to fit into a global design flow. Finally, thanks to the validation of the simulation flow with measurements, a deep sudy of the different components of the jitter has been conducted depending on the physical phenomenon being more or less destructive for the quality of the transmission. This study enabled to define design rules and design methodology taking into account the margins allocated from the results of the jitter analysis.

Bergkvist insjön AB is a sawmill yard which is capable of producing 350,000 cubic meter of timber every year this requires lot of internal resources. Sawmill operations can be classified as unloading, sorting, storage and production of timber. In the company we have trucks arriving at random they have to be unloaded and sent back at the earliest to avoid queuing up of trucks creating a problem for truck owners. The sawmill yard has to operate with two log stackers that does several tasks including transporting the logs from trucks to measurement station where the logs will be sorted into classes and dropped into pockets from pockets to the sorted timber yard where they are stored and finally from there to sawmill for final processing. The main issue that needs to be answered here is the lining up trucks that are waiting to be unload, creating a problem for both sawmill as well as the truck owners and given huge production volume, it is certain that handling of resources is top priority. A key challenge in handling of resources would be unloading of trucks and finding a way to optimize internal resources.To address this problem i have experimented on different ways of using internal resources, i have designed different cases, in case 1 we have both the log stackers working on sawmill and measurement station. The main objective of having this case is to make sawmill and measurement station to work all the time. Then in case 2, i have divided the work between both the log stackers, one log stacker will be working on sawmill and pocket_control and second log stacker will be working on measurement station and truck. Then in case 3 we have only one log stacker working on all the agents, this case was designed to reduce cost of production, as the experiment cannot be done in real-time due to operational cost, for this purpose simulation is used, preliminary investigation into simulation results suggested that case 2 is the best option has it reduced waiting time of trucks considerably when compared with other cases and it showed 50% increase in optimizing internal resources.

Performing simulations of large-scale bio-molecular systems has long been one of the great challenges of molecular biophysics. Phenomena, such as the folding and conformational rearrangement of proteins, often takes place over the course milliseconds-to-seconds. The methods of traditional molecular dynamics used to simulate such systems are on the other hand typically limited to giving trajectories of nanosecond-to-microsecond duration. The failure of traditional methods has thus motivated the development of many special purpose techniques that propose to capture the essential characteristics of systems over conventionally inaccessible timescales. This dissertation first focuses on presenting a set of advances made on one such technique, Milestoning. Milestoning gives a statistical procedure for recovering long trajectories of the system based on observations of many short trajectories that start and end on hypersurfaces in the system’s phase space. Justification of the method’s validity typically relies on the assumption that trajectories of the system lose all memory between crossing successive milestones. We start by giving a modified milestoning procedure in which both the memory loss assumption is relaxed and reaction mechanisms are more easily extracted. We follow with numerical examples illustrating the success of new procedure. Then we show how milestoning may be used to compute an experimentally relevant timescale known as the transit time (also known as the reaction path time). Finally, we discuss how time reversal symmetry may be exploited to improve sampling of the trajectory fragments that connect milestones. After discussing milestoning, the dissertation shifts focus to a different way of approaching the problem of simulating long timescales. We consider two polymers models that are sufficiently simple to permit numerical integration of the desired long trajectories of the system. In some limiting cases, we see their simplicity even permits some questions about the dynamcis to be answered analytically. Using these models, we make a series of experimentally verifiable predictions about the dynamics of unfolded polymers. / text

Magnetic nanostructures provide the opportunity to investigate a number ofmagnetic phenomena, and are of interest for their possible future applicationsin technology. In this project, the ferromagnetic response (FMR) of magnetic nanostructures to an electromagnetic excitation has been investigated using the micromagnetic simulations program Mumax3. The magnetic nanostructures in question were lattices of stadium shaped magnetic islands known as square articial spin ice. They are often characterized by the vortex in which four islands meet. Depending on the number of magnetic moment directed inwards or outwards from the vortex, four main vortex types can be created according to their magnetic energy. Lattices of square articial spin ice can exhibit articial magnetic monopoles connected by Dirac strings. Four congurations of square articial spin ice were investigated: a single stadium shaped island, two single vertices of different types, a lattice of 24 magnetic islands with two different spacings and types of center vertices, and a lattice of 60 magnetic islands for the case of inserted Dirac strings. The FMR spectra of these structures reveal several resonant modes of different intensities and frequencies. Of particular interest is the relationship between the intensity of a particular resonant mode and the number of inserted stings of reversed magnetization for the 4-by-4 lattice.

In our everyday life, turbulence is an omnipresent phenomenon and yet remains poorly understood. Its random and chaotic nature makes it a subject almost impossible to treat from the mathematical point of view and, at present, there is no real prospect of a simple analytic theory. Scientists have therefore regarded the numerical simulation as an alternative to compute the relevant properties of turbulent flows. In this context, our thesis aims at developing and using accurate computational methods, namely pseudo-spectral methods, for studying hydrodynamic (1st part) and magnetohydrodynamic (2nd part) turbulence. In the hydrodynamic part, Chapter I introduces the governing equations of fluid mechanics as well as the main issues related to the numerical study of turbulent flows. In particular, the Direct Numerical Simulations (DNS) of turbulence, in which accurate numerical solutions of the Navier-Stokes equations are obtained, are shown to be limited to moderately turbulent flows. Chapter II introduces the Large Eddy Simulation (LES) technique which aims at simulating highly turbulent flows and which is based on a separation of scales. In practice, it consists of simulating the large - resolved - scales of the flow explicitly while modelling the small - unresolved - scales. Two different approaches for modelling the kinetic energy of the unresolved scales are proposed and their respective advantages and drawbacks are discussed. Chapter III is devoted the study of the mixing-layer using both DNS and LES. It consists of an inhomogeneous turbulent flow which has been studied experimentally and for which well-documented measurements are available. A highly accurate DNS mimicking the same experiment has been produced. It allows to study the inhomogeneity and anisotropy properties of this flow. Also, LES of the same flow, using different models, have been evaluated. In Chapter IV, we explore a pseudo-spectral method to investigate turbulence in a pipe. In this case, the method has to take into account two additional difficulties: i) the presence of the boundary and ii) the axis singularity. We detail how to circumvent these issues. The second part of the thesis is devoted to magnetohydrodynamic (MHD) turbulence. It concerns phenomena where electrically conducting flows interact with electromagnetism and for which governing equations are derived in Chapter V. In Chapter VI, a detailed analysis of the energy transfers between the magnetic and velocity fields is performed thanks to a high resolution database of homogeneous MHD turbulence. It provides some insights to understand the physics of the nonlinear interactions and is also a valuable diagnostic in the framework of LES modelling. Finally, the inhomogeneous configuration studied in Chapter III has been extended to MHD. Several statistics related to the kinetic and magnetic energies are measured and LES of this flow are performed and presented in Chapter VII.

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