In this thesis, we attempt to obtain a class of generalized bilinear differential equations in (3+1)-dimensions by Dp-operators with p = 5, which have resonant solutions. We construct resonant solutions by using the linear superposition principle and parameterizations of wave numbers and frequencies. We test different values of p in Maple computations, and generate three classes of generalized bilinear differential equations and their resonant solutions when p = 5.

L’électronique de puissance est un domaine en mutation. Les environnements et les conditions de fonctionnement des modules de puissance sont de plus en plus sévères : hautes températures, tension et courant élevés. De plus, le frittage d’argent a été introduit dans les modules, en remplacement des joints brasés principalement composés de plomb. C’est la combinaison de ces évolutions qui ont motivés nos travaux. Dans l’objectif d’améliorer la conception des modules de puissance, ces travaux proposent d’augmenter la dissipation des modules grâce aux structures verticales-3D. Un onduleur triphasé vertical-3D a été conçut avec des puces Si reportées par frittage d’argent. Des caractérisations électriques et thermiques ont été réalisées et ont permis de montrer l’apport de cette technologie. Cette étude est couplée à des simulations numériques thermiques et électrostatiques permettant de mettre en lumière les enjeux de cette méthode d’assemblage. / Power electronics is a changing field. The environments and operating conditions of power modules are more severe: higher temperature, higher voltage and higher current. In addition, silver sintering was introduced in power modules to replace solders composed by lead. The combinations of these developments have motivated our work. In order to improve the design of the power modules our researches purpose to increase the dissipation of power modules with a3D-vertical structure. A three-phase inverter with3D-vertical structure has been designed with a Si dice sintered. Thermal and electrical characterizations were performed and allowed to show the contribution of this technology. This study is coupled to thermal and electrostatic Finite Element Method simulations to highlight and improve the possible issues of this assembly.

Network visualizations have been used for quit long time. Different disciplines use this visualization to compare a given dataset. Identifying better comparison approach that is used for information visualization is indispensable both for the people who are using it and for developers who are looking for a better way of visualizing huge data. In this thesis a task based approach has been used to analyze two different network comparison approaches namely Juxtaposition (showing different objects compared in separate space or time) and Superposition (overlaying objects in the same space). Thirty students at Linnaeus University have participated in the questionnaire to evaluate the usability of the two approaches. SPSS tool is used to analyze the data collected from the participants and the result explicitly indicates that there is no significant variation between Juxtaposition and Superposition comparison approaches. The result can be used as a recommendation for domain specific professionals and developers in their quest for better network comparison for their audience.

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<p>In this thesis, a practical superposition coding scheme based on multilevel low-density parity-check (LDPC) codes is proposed for discrete memoryless broadcast channels. The simulation results show that the performance of the proposed scheme approaches the information-theoretic limits. We also propose a method for optimizing the degree distribution of multilevel LDPC codes based on the analysis of EXIT functions.</p> / Master of Applied Science (MASc)

Polymeric adhesives play an increasingly critical role in today's engineering designs. When used, adhesively bonded components reduce or eliminate the need for bolted or welded connections. In many cases, this can reduce stress concentrations and weight. With energy dissipating adhesives, noise and vibration reduction are possible, as is the use of unique or complicated designs that could not otherwise be constructed. Adhesive properties however, can vary greatly with time, temperature, and environmental exposure conditions such as moisture. It is therefore critical, to understand the behavior of adhesives over the range of conditions that a bonded component might experience. In this work, the behavior of a urethane-based adhesive was characterized and long-term durability predictions were developed as a result of the data collected. The popular T-peel sample geometry has been used extensively in this study to explore the mechanics of a bonded system and the resulting impact on adhesive durability. The T-peel specimens used, consist of two aluminum sheets or adherends bonded together, with tabs bent back in the shape of a "T" for gripping in a universal load frame. Unlike some other test geometries, T-peel samples are often made with relatively thin adherends that may experience significant plastic deformation during testing. This extraneous energy dissipation greatly complicates the analysis to extract meaningful fracture properties of the adhesive. During testing, the load required to propagate a crack in the adhesive layer is measured at fixed displacement rates. The total system energy can then be partitioned into the energy dissipated within the adhesive (fracture energy), and the energy dissipated through plastic work in bending of the adherends. By performing these tests at different temperatures and rates, the calculated fracture energies span a wide range of possible material behavior. Using the principles of Time Temperature Superposition (TTS), the collected data can be shifted to different times or temperatures. This behavior is well understood in polymer physics, and is made possible with material specific "shift factors". By using the principles of TTS, data collected in in a relatively short experimental window, can be used to accurately predict the behavior of the adhesive in years or even decades. In this work, nearly 200 T-peel samples were tested in four different studies. A preliminary set of unaged specimens was used to develop testing and data analysis methodologies. A second set of unaged samples was tested over a wide range of temperatures and rates, in addition to a third group, subjected to constant moisture and cyclically varying temperature. The final set of specimens, was exposed to 20 separate isothermal aging conditions. The experimental data showed that the 400+ cycles, were insufficient to statistically distinguish these samples from their unaged counterparts. Additionally, samples aged for up to 2000 hours in a dry environment, or 500 hours in a wet environment, showed no reduction in fracture energies in comparison with unaged samples. Specimens aged for more than 500 hours however, were observed to have a significant decrease in fracture energy values. Strong correlations between the thickness of the adhesive layer and estimated fracture energy values were found in this study. As adhesive thickness varied substantially due to manufacturing differences in the specimens tested, new analysis techniques were developed to deal with the variations in adhesive thickness. A MATLAB code based on the ICPeel program, was written to provide a spatial variation of parameters such as adhesive thickness, peel load, and fracture energy. This provided additional insights into the behavior of these T-peel coupons, and prompted the investigation of the Universal Peel Diagram concept. While this diagram was not found to be applicable to the adhesive tested in this study, the analysis indicated that T-peel coupons could be multivalued. That is, a single measured load value does not always describe an adhesive's fracture energy (as is widely believed). Depending on the sample's geometry and material properties, several measured loads could cause debonding. This has potentially far reaching implications on the selection of appropriate T-peel test geometries, as a single measured load is often assumed to correlate to an adhesive's true fracture energy. In this work, both aged and unaged T-peel specimens were tested and the basis of the Universal Peel Diagram investigated. Given sufficient exposure times to moisture, elevated temperatures were found to significantly reduce the amount of energy dissipated in the urethane-based adhesive. Additionally, the Universal Peel Diagram indicated that for some systems, the load required for debond is in fact, multivalued. Therefore, care should be taken when designing a T-peel test configuration to avoid the multivalued regions. / Master of Science / Polymeric adhesives play an increasingly critical role in today's engineering designs. When used, adhesively bonded components reduce or eliminate the need for bolted or welded connections, reducing their weight in the process. With adhesives, noise and vibration reduction are possible, as is the use of unique or complicated designs that could not otherwise be constructed. Adhesive properties, however, can vary greatly with time, temperature, and other environmental exposure conditions such as moisture. It is therefore critical to understand the behavior of adhesives over the range of conditions that a bonded component might experience. In this work, the behavior of a urethane-based adhesive was characterized in order to develop long-term durability predictions. Numerous test methods have been developed to characterize the behavior of adhesively bonded joints. In this work, T-peel specimens were used consisting of two aluminum sheets (the adherends), bonded together with tabs bent back in the shape of a "T" for gripping in a universal load frame. During testing, the load required to propagate a crack in the adhesive layer is measured. An outcome of this measurement and subsequent data analysis is the fracture energy—a measure of the effectiveness of the adhesive in transferring loads. If we perform these tests at different temperatures and loading rates, we can determine fracture energy values which span a wide range of possible material behavior. Using principles from basic polymer physics, the collected data can be shifted to different times or temperatures enabling us to accurately predict the behavior of the adhesive over years or even decades. In this work, nearly 200 T-peel samples were tested in four different studies. A preliminary set of unaged specimens was used to develop testing and data analysis methodologies. Unaged and cyclically (temperature) aged samples were tested over a wide range of temperatures and rates. The fourth set of specimens was subjected to 20 separate isothermal aging conditions and also tested at different temperatures and rates. The experimental data showed that the 400+ temperature cycles were insufficient to damage these samples significantly. Additionally, samples aged for up to 2000 hours in a dry environment, or 500 hours in a wet environment showed no reduction in performance in comparison with unaged samples. Specimens aged for more than 500 hours in a wet environment however, demonstrated a significant decreases in fracture energy values. Strong correlations between the thickness of the adhesive layer and estimated fracture energy values were found in this study, and new analysis techniques were developed to analyze the effect of these thickness variations on the joint performance.

This thesis presents the results of testing and modeling conducted to characterize the performance of 3M™ VHB™ structural glazing tape in both shear and tension. Creep rupture testing results provided the failure time at a given static load and temperature, and ramp-to-fail testing results provided the ultimate load resistance at a given rate of strain and temperature. Parallel testing was conducted on three structural silicone sealants to compare performance. Using the time temperature superposition principle, master curves of VHB tape storage and loss moduli in shear and tension were developed with data from a dynamic mechanical analyzer (DMA). The thermal shift factors obtained from these constitutive tests were successfully applied to the creep rupture and ramp-to-fail data collected at 23°C, 40°C, and 60°C (73°F, 104°F, and 140°F), resulting in master curves of ramp-to-fail strength and creep rupture durability in shear and tension. A simple linear damage accumulation model was then proposed to examine the accumulation of wind damage if VHB tape is used to attach curtain wall glazing panels to building facades. The purpose of the model was to investigate the magnitude of damage resulting from the accumulation of sustained wind speeds that are less than the peak design wind speed. The model used the equation derived from tensile creep rupture testing, extrapolated into the range of stresses that would typically be generated by wind loading. This equation was applied to each individual entry in the data files of several real wind speed histories, and the fractions of life used at each entry were combined into a total percentage of life used. Although the model did not provide evidence that the established design procedure is unsafe, it suggested that the accumulation of damage from wind speeds below the peak wind speed could cause a VHB tape mode of failure that merits examination along with the more traditional peak wind speed design procedure currently recommended by the vendor. / Master of Science

Les nuages de points en trois dimensions sont un format de données très commun en robotique mobile. Ils sont souvent produits par des capteurs spécialisés de type lidar. Les nuages de points générés par ces capteurs sont utilisés dans des tâches impliquant de l’estimation d’état, telles que la cartographie ou la localisation. Les algorithmes de recalage de nuages de points, notamment l’algorithme ICP (Iterative Closest Point), nous permettent de prendre des mesures d’égo-motion nécessaires à ces tâches. La fusion des recalages dans des chaînes existantes d’estimation d’état dépend d’une évaluation précise de leur incertitude. Cependant, les méthodes existantes d’estimation de l’incertitude se prêtent mal aux données en trois dimensions. Ce mémoire vise à estimer l’incertitude de recalages 3D issus d’Iterative Closest Point (ICP). Premièrement, il pose des fondations théoriques desquelles nous pouvons articuler une estimation de la covariance. Notamment, il révise l’algorithme ICP, avec une attention spéciale sur les parties qui sont importantes pour l’estimation de la covariance. Ensuite, un article scientifique inséré présente CELLO-3D, notre algorithme d’estimation de la covariance d’ICP. L’article inséré contient une validation expérimentale complète du nouvel algorithme. Il montre que notre algorithme performe mieux que les méthodes existantes dans une grande variété d’environnements. Finalement, ce mémoire est conclu par des expérimentations supplémentaires, qui sont complémentaires à l’article. / Three-dimensional point clouds are an ubiquitous data format in robotics. They are produced by specialized sensors such as lidars or depth cameras. The point clouds generated by those sensors are used for state estimation tasks like mapping and localization. Point cloud registration algorithms, such as Iterative Closest Point (ICP), allow us to make ego-motion measurements necessary to those tasks. The fusion of ICP registrations in existing state estimation frameworks relies on an accurate estimation of their uncertainty. Unfortunately, existing covariance estimation methods often scale poorly to the 3D case. This thesis aims to estimate the uncertainty of ICP registrations for 3D point clouds. First, it poses theoretical foundations from which we can articulate a covariance estimation method. It reviews the ICP algorithm, with a special focus on the parts of it that are pertinent to covariance estimation. Then, an inserted article introduces CELLO-3D, our data-driven covariance estimation method for ICP. The article contains a thorough experimental validation of the new algorithm. The latter is shown to perform better than existing covariance estimation techniques in a wide variety of environments. Finally, this thesis comprises supplementary experiments, which complement the article.

Dans les dernières années, beaucoup de progrès a été fait dans le domaine des voitures autonomes. Plusieurs grandes compagnies travaillent à créer un véhicule robuste et sûr. Pour réaliser cette tâche, ces voitures utilisent un lidar pour la localisation et pour la cartographie. Iterative Closest Point (ICP)est un algorithme de recalage de points utilisé pour la cartographie basé sur les lidars. Ce mémoire explore des approches pour améliorer le minimisateur d’erreur d’ICP. La première approche est une analyse en profondeur des filtres à données aberrantes. Quatorze des filtres les plus communs (incluant les M-estimateurs) ont été testés dans différents types d’environnement, pour un total de plus de 2 millions de recalages. Les résultats expérimentaux montrent que la plupart des filtres ont des performances similaires, s’ils sont correctement paramétrés. Néanmoins, les filtres comme Var.Trim., Cauchy et Cauchy MAD sont plus stables à travers tous les types environnements testés. La deuxième approche explore les possibilités de la cartographie à grande échelle à l’aide de lidar dans la forêt boréale. La cartographie avec un lidar est souvent basée sur des techniques de Simultaneous Localization and Mapping (SLAM) utilisant un graphe de poses, celui-ci fusionne ensemble ICP, les positions Global Navigation Satellite System (GNSS) et les mesures de l’Inertial Measurement Unit (IMU). Nous proposons une approche alternative qui fusionne ses capteurs directement dans l’étape de minimisation d’ICP. Nous avons réussi à créer une carte ayant 4.1 km de tracés de motoneige et de chemins étroits. Cette carte est localement et globalement cohérente. / In recent years a lot of progress has been made in the development of self-driving cars. Multiple big companies are working on creating a safe and robust autonomous vehicle . To make this task possible, theses vehicles rely on lidar sensors for localization and mapping. Iterative Closest Point (ICP) is a registration algorithm used in lidar-based mapping. This thesis explored approaches to improve the error minimization of ICP. The first approach is an in-depth analysis of outlier filters. Fourteen of the most common outlier filters (such as M-estimators) have been tested in different types of environments, for a total of more than two million registrations. The experimental results show that most outlier filters have a similar performance if they are correctly tuned. Nonetheless, filters such as Var.Trim., Cauchy, and Cauchy MAD are more stable against different environment types. The second approach explores the possibilities of large-scale lidar mapping in a boreal forest. Lidar mapping is often based on the SLAM technique relying on pose graph optimization, which fuses the ICP algorithm, GNSS positioning, and IMU measurements. To handle those sensors directly within theICP minimization process, we propose an alternative technique of embedding external constraints. We manage to create a crisp and globally consistent map of 4.1 km of snowmobile trails and narrow walkable trails. These two approaches show how ICP can be improved through the modification of a single step of the ICP’s pipeline.