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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
491

Utvärdering av gränssnitt i en helikoptersimulator : En taktil, en visuell samt en bimodal display som visar horisontell och vertikal drift

Norén, Caroline January 2014 (has links)
Föreliggande studie har undersökt flera gränssnitt i en helikoptersimulator som visar horisontell och vertikal drift; en taktil, en visuell och en bimodal display. Syftet med studien var att undersöka om det är med fördel att använda displayer som visar på drift horisontellt och vertikalt. Dessutom var syftet att undersöka om taktil display leder till lika bra prestation som med en visuell display, eller kommer kunna användas som komplement till den visuella i en bimodal kombination. I studien deltog 12 försöksdeltagare som fick i uppgift att i en helikoptersimulator försöka stå stilla i luften (s.k. hovra) på en höjd på 8000 fot med hjälp av varje driftdisplay under två minuter. Förutom de tre driftdisplayerna skulle även försöksdeltagarna hovra utan några hjälpmedel som visar på drift. Resultatet visade att det är med fördel att använda alla tre driftdisplayer för att minska drift horisontellt. Resultatet visade dessutom att det är med fördel att använda en visuell display och en bimodal display för att minska drift vertikalt. Slutsatsen av studien är således att det är med fördel att använda driftdisplayer för att minska på drift. Den taktila displayen fungerar inte lika bra som den visuella i undvikandet av drift, men går att användas som komplement i en bimodal kombination.
492

Etude des effets des hétérogénéités spatiales tridimensionnelles des nuages sur les observables lidar et radar embarqués sur plateforme satellite / Study of the effects of three-dimensional spatial heterogeneities of clouds on lidar and radar observables embedded on a satellite platform

Alkasem, Alaa 11 May 2017 (has links)
Les nuages montrent des variabilités tridimensionnelles complexes (3D) dans leurs propriétés géométriques, optiques et microphysiques horizontales et verticales. Généralement et pour des raisons pratiques, les nuages sont supposés être homogènes et parallèles dans les algorithmes de calcul du signal lidar/radar (problème direct) et dans les algorithmes de récupération des propriétés des nuages (problème inverse). L'objectif de ce travail est d'évaluer les effets de l'hétérogénéité des nuages et de la diffusion multiple sur des caractéristiques mesurées directement par le lidar/radar, nous ne traitons que les sources d'erreurs liées au problème direct. Nos évaluations sont basées sur l'échantillonnage aléatoire et sur la comparaison entre les profils moyens des nuages 3D et des nuages 1D équivalents plan-parallèles. Nous avons développé et validé un outil à cet effet. Le simulateur lidar/radar/radar Doppler (McRALI). Il est basé sur le modèle 3DMCPOL (Cornet et al., 2010). Les nuages 3D utilisés sont générés par le générateur de champs de nuages 3D (3DCLOUD_V2) (Szczap et al., 2014). Les comparaisons avec des publications et des codes de référence, ont montré de bonnes cohérences entre le code McRALI et les résultats publiés. On a étudié les effets de l'hétérogénéité 3D des nuages sur trois échelles 333 m, 1 km et 5 km. Les résultats obtenus ont montré que les biais sur le coefficient de rétrodiffusion β, sur le coefficient de rétrodiffusion intégré γ et sur le facteur de dépolarisation δ augmentent avec l’augmentation de l’échelle et l’épaisseur optique. L’étude sur un nuage de type cirrus de cristaux de glace plaquette ont montré que les profils moyens de β ainsi que de γ sont statistiquement égaux à l’échelle de 333 m. Au contraire, à l’échelle de 1 km les biais sont statistiquement significatifs. Le biais sur δ est statistiquement significatif pour les deux échelles. Les tests sur les mesures de radar CPR Doppler EarthCARE ont montré qu’il y a un écart sur la vitesse Doppler mesuré proche de la discontinuité dans un nuage discontinu, cet écart dépond le degré de la discontinuité, les propriétés optiques et géométriques du nuage et la géométrie du système radar. Ce travail contribue à une meilleure compréhension des effets de l'hétérogénéité des nuages sur les caractéristiques mesurées directement par le lidar / radar. / Clouds display complex three-dimensional (3D) variability in their horizontal and vertical geometric, optical and microphysical properties. Generally and for practical reasons, the clouds are supposed to be homogeneous and parallel in the algorithms for calculating the lidar / radar signal (direct problem) and in the algorithms for the retrieval of the properties of the clouds (inverse problem). The objective of this work is to evaluate the effects of cloud heterogeneity and multiple scattering on the characteristics measured directly by the lidar / radar. In this study, we only deal with the sources of errors related to the direct problem. Our assessments are based on random sampling and comparison between the average profiles of 3D clouds and 1D equivalent plane-parallel clouds. Therefore, we developed and validated a tool called the lidar / radar / Doppler radar simulator (McRALI). The latter tool is based on the 3DMCPOL model (Cornet et al., 2010). The 3D clouds, used in the current study, were generated by the 3D cloud field generator (3DCLOUD_V2) (Szczap et al., 2014). The tested McRALI code revealed good coherence with earlier published studies. We studied the effects of 3D cloud heterogeneity on three scales 333 m, 1 km and 5 km. The results obtained showed that the biases on the backscattering coefficient β, on the integrated backscattering coefficient γand on the depolarization factor δ increase with increasing the scale and the optical thickness. The study of a cirrus cloud of ice crystals showed that the average profiles of β as well as the γ are statistically equal to the 333 m scale. On the contrary, the biases are statistically significant at 1 km scale. The bias on δ is statistically significant for both scales. The tests carried out on the EarthCARE Doppler CPR radar measurements showed that there is a difference in the measured Doppler velocity close to the discontinuity in a discontinuous cloud. This difference is due to the degree of the discontinuity, the optical, the geometrical properties of the cloud and the geometry of the radar system. This work contributes to better understanding of the effects of cloud heterogeneity on the characteristics measured directly by the lidar / radar.
493

Méthodologie pour l'évaluation et la restitution des couleurs : application à la simulation de conduite / Methodology for the evaluation and the return of colors : application in the simulation of conduct

Vidal, Quentin 23 September 2016 (has links)
À l'heure actuelle, la voiture n'est plus un objet qui permet seulement de transporter une personne d'un endroit à un autre et il suffit de regarder les publicités automobiles pour en avoir la certitude. En effet, le champ lexical utilisé dans ces dernières se rapproche plus des sens, voire du rêve, que de la mobilité. La voiture n'est donc plus reléguée au simple rang de transporteur, mais à celui de véritable habitat dans lequel nous sommes amenés à découvrir de nouvelles sensations. Dans ce cadre, la réalité virtuelle est l'un des outils qui est utilisé dans l'industrie automobile afin de vérifier, en amont, l'ergonomie d'un prototype. En effet, en immergeant partiellement un usager dans cette autre réalité, il est possible d'avoir des retours pertinents quant à une maquette numérique, une interface, etc. Cela permet ainsi de tester différentes pièces avant même leur production ce qui est un gain notable en temps et en argent. Cependant, l'utilisation de cette technologie pose des questions quant au photo-réalisme de la reproduction virtuelle, et ce, tout particulièrement lorsque des pièces tels que les blocs optiques de la voiture sont analysés. Sur cette thématique, des études antérieures ont montré que le système reproduisait correctement les intensités lumineuses, mais pas la couleur des phares. Ainsi, dans le contexte du rendu de phare photoréaliste, nous avons tout d'abord proposé deux échelles colorimétriques afin d'analyser à quel point nous pouvions nous éloigner de la réalité sans que la différence de couleur ne gêne l'utilisateur final. À la suite de cela, nous avons proposé un système qui suit, au jour le jour, le vieillissement du simulateur dans le but de corriger ladite différence colorimétrique. Enfin, dans une étude exploratoire, nous avons souhaité regarder comment le comportement des conducteurs pouvait être influencé par la couleur des phares de voiture. Nous supposions que ce facteur pouvait avoir un impact sur la perception des distances et donc sur la distance intervéhiculaire à laquelle le conducteur se positionnait. / Nowadays, a car is not limited to the transportation of one or many people. Indeed, if we take a look at some automobile advertisement, it's more the idea of desir or even dream that is conveyed. Therefore, a car is no longer related to the simple rank of carrier but is a real new habitat in which we will discover new sensations. In this context, the car company that offers the best experience at the better price should be the one that dominates the market. For that purpose, virtual reality is one of the tools that is used by the automotive industry. Indeed, by partially immerging a user in this "other" reality, it is possible to get a relevent feedback for a digital model, Human-Machine Interface, etc. This allows to test different pieces before their production which is a significant gain in time and money. However, the use of this technology raises questions about the fidelity of the reproduction. Do the virtual reproduction of an object is close enough to the original ? If there is a difference, how could it impact the judgment of a person ? Those questions are even more important when it comes to the virtual evaluation of car headlight because they must respect international standard in term of color and light intensity. For these points, previous studies have shown that the system correctly reproduced the light intensities but not the headlights color. Thus, in the context of rendering photorealistic headlights, we first investigate on how a color difference can affect, discomfort the headlight specialist. To this end, we lead psychometric experiments and proposed two color difference scales (one for a naïve population and the other for an expert one). With this first result, we have proposed a system that follows, day by day, the aging simulator in order to correct the said color difference. Finally, in an exploratory study, we wanted to look at how the driver behavior could be influenced by the color of the car headlights. We assumed that this factor could affect depth perception and therefore the distance intercar in which the driver was positioning.
494

Contribution à la modélisation et à la prédiction de défaillances sur les moteurs diesel marins / Contribution on modeling and prediction of failures on marine diesel engines

Moussa-Nahim, Hassan 22 February 2016 (has links)
Ce travail présente un modèle orienté vers le développement d’un simulateur pour un moteur diesel marin. Dans le but d’avoir un simulateur qui répond aux besoins du moteur étudié au niveau de l’efficacité, la rapidité, et la prise en considération des défauts, le modèle étudié est basé sur des modélisations physiques, semi physique, empirique, mathématique et thermodynamique. Le modèle du moteur est divisé en plusieurs sous-modèles chacun présente un système réel, ces systèmes sont : le refroidissement, la lubrification, l’air, l’injection, la combustion et les émissions. Les sous-modèles et les caractéristiques dynamiques du chaque bloc sont conçus en respectant les équations principales du fonctionnement du moteur ainsi que les données expérimentales collectées du banc d’essai du moteur marin diesel fabriqué par la société SIMB sous la référence 6M26SRP1. Ce modèle a été implémenté sur Matlab/Simulink, et la simulation calcule les variables suivantes : pression, température, efficacité, échange de chaleur, angle de vilebrequin, débit du fuel et émissions, et ceci dans les différentes sous-blocs. Le simulateur est utilisé pour montrer la performance du moteur lors de l’occurrence des défauts et peut aider dans l’application des stratégies d’optimisation pour le dimensionnement, de diagnostic et de pronostic. / This work presents a simulator model of a marine diesel engine based on physical, semi-physical, mathematical and thermodynamic equations, allowing fast predictive simulations. The whole engine system is divided into several functional blocs: cooling, lubrication, air, injection, combustion and emissions. The sub-models and dynamic characteristics of individual blocs are established according to engine working principles equations and experimental data collected from a marine diesel engine test bench for SIMB Company under the reference 6M26SRP1. The overall engine system dynamics is expressed as a set of simultaneous algebraic and differential equations using sub-blocs and S-Functions of Matlab/Simulink. The simulation of this model, implemented on Matlab/Simulink has been validated and can be used to obtain engine performance, pressure, temperature, efficiency, heat release, crank angle, fuel rate, emissions at different sub-blocs. The simulator is used to study the engine performance in faulty conditions, and can be used also to assist marine engineers in FDI (fault detection and isolation) as well as designers to predict the behavior of the cooling system, lubrication system, injection system, combustion, emissions, in order to optimize the dimensions of different components.
495

[en] GEOMECHANICAL EFFECTS ON PETROLEUM RESERVOIR SIMULATIONS / [pt] EFEITOS GEOMECÂNICOS NA SIMULAÇÃO DE RESERVATÓRIOS DE PETRÓLEO

FLAVIA DE OLIVEIRA LIMA FALCAO 01 November 2002 (has links)
[pt] Simuladores de escoamento em reservatórios são ferramentas importantes na otimização do desenvolvimento de um campo de petróleo. Estes simuladores modelam o escoamento multifásico através de meios porosos compressíveis, levando em conta as equações de equilíbrio de fases, as leis de fluxo e a variação volumétrica do meio poroso associada à variação da pressão de poros do sistema. As tensões in situ são consideradas através da aplicação de tensões constantes no contorno do reservatório. Este trabalho descreve a utilização de um simulador convencional de reservatório, baseado em diferenças finitas com e sem um módulo geomecânico, e a utilização de um simulador acoplado, que resolve as equações de escoamento e de tensão num mesmo código de elementos finitos. Nesta dissertação são feitas comparações entre os modelos geomecânicos aproximado e rigoroso oferecidos pelos simuladores comerciais, além de ser apresentada uma análise de situações em que esta última forma deve ser realmente considerada. O objetivo deste trabalho é analisar a influência das tensões in situ em reservatórios de petróleo com base na comparação entre os campos de poropressões obtidos a partir da modelagem de um mesmo sistema com os dois simuladores geomecânicos. São apresentadas as formas de acoplamento e a formulação utilizada em cada um dos modelos. Os modelos geomecânicos utilizados em cada um dos simuladores são comparados. É feita uma comparação entre os resultados obtidos pelos dois simuladores a partir de um modelo bidimensional. / [en] Numerical simulators for reservoir flow analysis are important tools for the optimization of oil field development. These simulators model the multiphase flow through compressible porous medium taking into account the phase equilibrium equations, flow laws and the rock volumetric change associated to the pore pressure change during production. Some simulators have been associated with stress analysis modules in order to use the pore pressure field obtained by the flow simulator and update the stress field within the reservoir. This dissertation describes the use of a conventional reservoir simulator based on finite differences that models multiphase flow in porous media, with and without a geomechanical module, and the use of a fully-coupled simulator that solves both the flow and stress equations in a single finite element code. This dissertation compares the two geomechanical modules, the approximated and the precise, offered by commercial simulators, and analyses the situations in which the rigorous form should be considered, or not. The aim of this dissertation is to investigate the influence of in situ stresses in petroleum reservoirs based on the comparison of the pore pressure fields obtained from the modeling of the same system with both geomechanical simulators. The coupling and formulation used in each model are presented. The geomechanical models of both simulators are described. A comparison of the simulators is made using a bidimensional model.
496

From high level architecture descriptions to fast instruction set simulators

Wagstaff, Harry January 2015 (has links)
As computer systems become increasingly complex and diverse, so too do the architectures they implement. This leads to an increase in complexity in the tools used to design new hardware and software. One particularly important tool in hardware and software design is the Instruction Set Simulator, which is used to prototype new architectures and hardware features, verify hardware, and test and debug software. Many Architecture Description Languages exist which facilitate the description of new architectural or hardware features, and generate a tools such as simulators. However, these typically suffer from poor performance, are difficult to test effectively, and may be limited in functionality. This thesis considers three objectives when developing Instruction Set Simulators: performance, correctness, and completeness, and presents techniques which contribute to each of these. Performance is obtained by combining Dynamic Binary Translation techniques with a novel analysis of high level architecture descriptions. This makes use of partial evaluation techniques in order to both improve the translation system, and to improve the quality of the translated code, leading a performance improvement of over 2.5x compared to a naïve implementation. This thesis also presents techniques which contribute to the correctness objective. Each possible behaviour of each described instruction is used to guide the generation of a test case. Constraint satisfaction techniques are used to determine the necessary instruction encoding and context for each behaviour to be produced. It is shown that this is a significant improvement over benchmark-driven testing, and this technique has led to the discovery of several bugs and inconsistencies in multiple state of the art instruction set simulators. Finally, several challenges in ‘Full System’ simulation are addressed, contributing to both the performance and completeness objectives. Full System simulation generally carries significant performance costs compared with other simulation strategies. Crucially, instructions which access memory require virtual to physical address translation and can now cause exceptions. Both of these processes must be correctly and efficiently handled by the simulator. This thesis presents novel techniques to address this issue which provide up to a 1.65x speedup over a state of the art solution.
497

Conception et mise à l’épreuve d’une fonctionnalité de rétroaction d’un simulateur sur écran destiné aux personnes étudiantes en sciences infirmières / Conception and testing of feedback functionality in a screen simulator designed for nursing students

Westover, Stephany January 2017 (has links)
Introduction : La rétroaction sur la performance des personnes étudiantes infirmières lors de l’utilisation de simulateur de patients sur ordinateur contribuerait à l’apprentissage et au développement du raisonnement clinique en supportant la métacognition (Zary et al., 2006). Or à notre connaissance, la forme et le contenu de ce type de rétroaction demeure peu discuté dans les écrits scientifiques. Objectif : Ce projet de recherche comportait trois objectifs. Le premier était de contribuer au développement d’une fonctionnalité de rétroaction dans un simulateur sur écran, le second visait à documenter la perception de son utilité à la suite d’une expérimentation guidée en laboratoire auprès de personnes étudiantes infirmières et, enfin, le troisième objectif visait à décrire l’appréciation générale du simulateur par les personnes participantes. Méthodes : Un devis de recherche descriptif avec méthodes mixtes auprès d’un échantillon de convenance constitué d’étudiantes et étudiants en sciences infirmières d’une université québécoise a été retenu pour cette étude. Le modèle de rétroaction PROMPTED (Rudland et al., 2013) a été retenu pour orienter la conception de la rétroaction dans le simulateur sur écran. L’accès au simulateur s’est fait par un lien web et, par la suite, les personnes participantes devaient compléter un questionnaire web autoadministré pour documenter leur appréciation de la rétroaction fournie pendant la simulation et du simulateur sur écran en soi. De plus, des entrevues ont été réalisées pour enrichir la description de l’utilité perçue de la rétroaction offerte dans le simulateur sur écran. Résultats : La rétroaction intégrée dans le simulateur sur écran selon les principes du modèle PROMPTED a permis de guider et de bien renseigner les étudiantes au cours de l’activité. Les données recueillies suggèrent l’appréciation de l’utilisation de la rétroaction en cours d’activité plutôt que d’avoir seulement un solutionnaire à la fin de l’exercice. Conclusion : En plus d’apporter une plus-value au simulateur sur écran par rapport à ce qui se retrouve sur le marché, ce projet contribue à l’avancement des connaissances sur l’utilité de la présence de rétroaction dans les simulateurs sur écran lors de la formation infirmière. / Abstract : Background: Feedback on nursing students’ performance when using a screen simulator could contribute to the learning and development of clinical reasoning by supporting metacognition (Zary et al., 2006). To our knowledge, the form and content of this type of feedback remains slightly discussed in scientific literature. Objective: This research project had three objectives. The first was to contribute to the development of a feedback functionality in a screen simulator, the second was to document the perception of its usefulness following a laboratory-guided experimentation with nursing students, and finally, the third objective aimed to describe its overall appreciation of the simulator. Methods: A descriptive research design with mixed methods was used with a convenience sample of nursing students of a university in Quebec. The PROMPTED feedback model (Rudland et al., 2013) was chosen to guide the conception of feedback in the screen simulator. Access to the simulator was via a web link and subsequently, the participants had to complete a self-administered web questionnaire of their appreciation of the feedback provided during the simulation as well as the screen simulator per se. In addition, interviews were conducted to enrich the description of the perceived usefulness of the feedback provided in the screen simulator. Results: Feedback integrated into the screen simulator in accordance with the PROMPTED Model has helped to guide and to inform the students during the activity. The data collected suggest the use of reel-time continuous feedback rather than only giving the answers at the end of the exercise. Conclusion: In addition to the value upgrade of the screen simulator compared to what is on the market, this project has contributed to the advancement of knowledge on the usefulness of feedback in screen simulators in nursing education.
498

Automatic Generation Of Compiled Cycle Level Microarchitecture Simulators For Superspeculative Processors

Chandran, Priya 06 1900 (has links) (PDF)
No description available.
499

Design and Development of an Intelligent Energy Controller for Home Energy Saving in Heating/Cooling System

Abaalkhail, Rana January 2012 (has links)
Energy is consumed every day at home as we perform simple tasks, such as watching television, washing dishes and heating/cooling home spaces during season of extreme weather conditions, using appliances, or turning on lights. Most often, the energy resources used in residential systems are obtained from natural gas, coal and oil. Moreover, climate change has increased awareness of a need for expendable, energy resources. As a result, carbon dioxide emissions are increasing and creating a negative effect on our environment and on our health. In fact, growing energy demands and limited natural resource might have negative impacts on our future. Therefore, saving energy is becoming an important issue in our society and it is receiving more attention from the research community. This thesis introduces a intelligent energy controller algorithm based on software agent approach that reduce the energy consumption at home for both heating and cooling spaces by considering the user’s occupancy, outdoor temperature and user’s preferences as input to the system. Thus the proposed approach takes into consideration the occupant’s preferred temperature, the occupied and unoccupied spaces, as well as the time spent in each area of the home. A Java based simulator has been implemented to simulate the algorithm for saving energy in heating and cooling systems. The results from the simulator are compared to the results of using HOT2000, which is Canada’s leading residential energy analysis and rating software developed by CanmetENERGY’s Housing, Buildings, Communities and Simulation (HBCS) group. We have calculated how much energy a home modelled will use under emulated conditions. The results showed that the implementation of the proposed energy controller algorithm can save up to 50% in energy consumption in homes dedicated to heating and cooling systems compared to the results obtained by using HOT2000.
500

Tribological evaluation of joint fluid and the development of a synthetic lubricant for use in hip joint simulators

Opperman, Tertius 28 July 2005 (has links)
Over the years, different lubricants have been used to operate hip simulators. The current applicable ISO standard (ISO 14242-1:2002) recommends the use of 25% calf serum diluted with deionised water. The standard further recommends that the fluid be changed and the acetabular cup be weighed every 500 000 cycles. This procedure results in a loss of both the third body wear particles and the wear pattern. The purpose of this study was to develop a synthetic lubricant that would map the viscosity and lubricity properties of joint fluid (“synovial fluid”) over the whole duration of a simulator test, which is typically five million cycles. The first objective of this study was to find the effect of temperature increase on the viscous and lubricative properties of joint fluid retrieved from both primary and revision patients prior to surgery. The lubricity tests were done on a Linear-Oscillation Test Machine (SRV machine). Three test temperatures were used namely 38ºC, 50ºC and 60ºC. The load at failure and the average coefficient of friction were parameters measured during these tests. A decrease in the load at failure was found for an increase in test temperature, while the coefficient of friction stayed relatively stable. The viscosity tests were done using a Brookfield Viscometer. The three test temperatures mentioned above, were copied. The joint fluid tested showed pseudoplastic flow behaviour. An increase in the viscosity as a function of test temperature increase and a magnitude of shear rate was observed. The second objective of this study was to develop a synthetic lubricant that had the same average properties than that found for the retrieved joint fluid. A mixture of three different chemicals, namely Poloxamer 188, Xanthan Gum and Lube Boosterâ II was used to map the viscous and lubricative properties of the joint fluid. A comparative test using the synthetic lubricant and bovine serum was performed in a custom-built simulator. Wear debris was sampled at 500 000 cycle intervals up to 4 500 000 cycles. During these intervals the bovine serum stations were drained and washed with deionised water, but not stripped and weighed as specified in the ISO standard. This was done intentionally to preserve the wear pattern during the entire test. The synthetic lubricant stations were not stripped or drained during these intervals. This ensured that the wear pattern was maintained and that the effect of accumulative wear could be investigated throughout the duration of the test. The wear debris from the test was then compared to wear debris retrieved from scar tissue of revision patients. The wear debris that was found in the scar tissue retrieved from patients was similar in shape and size to that which was found in the simulator using bovine serum and the synthetic lubricant. It can thus be concluded that an acceptable lubricant had been developed to replace the current test medium in the simulators. / Dissertation (MEd (Mechanical Engineering))--University of Pretoria, 2006. / Mechanical and Aeronautical Engineering / unrestricted

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