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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.
61

Robotique nomade pour la restauration des écosystèmes dégradés / Nomadics robotics for restoring degraded ecosystems

Zaoui, Mohammed 17 September 2015 (has links)
La dégradation des terres dans le monde affecte directement plus d’un milliard d’hectares. Elle menace près de 35% des terres de la planète ainsi que les moyens de subsistance de deux milliards d’individus. Les estimations des pertes financières sont considérables chaque année. La dégradation des terres arides et semi-arides est une entrave au développement des pays concernés. Ce problème demeure insoluble et la communauté internationale organisée au sein de plusieurs instances n’ayant pas trouvé de solution pérenne, assiste impuissante à la progression du fléau malgré les efforts et expérimentations menées à travers le monde. L’urgence est de mise pour trouver des solutions qui soient à la fois techniques, sociales, économiques et culturelles.Ce constat appelle des réponses et la nécessité d’exploiter des approches basées sur les avancées des nouvelles techniques. La robotique mobile est une piste qui peut contribuer dans un avenir proche à freiner ce phénomène. Cette technologie recèle d’immenses possibilités dans plusieurs domaines : médical, aide à la personne, militaire, agricole et bien entendu dans la restauration des écosystèmes. La thèse s’inscrit dans le projet R-Stepps pour évaluer les capacités de résilience d’une solution basée sur les techniques robotiques. Elle expérimente une flotte de robots pour lutter contre la dégradation des terres et l’avancée de la désertification. Nous avons étudié et exploré les moyens de mettre au point une flotte de robots nomades pour remplir des missions de restauration des écosystèmes dégradés. Pour construire des systèmes mécatroniques simples et robustes nous avons mis au point des robots limités à une seule tâche.Nous avons développé une plateforme expérimentale composée de cinq robots capables de se coordonner et d’accomplir chacun une tâche spécifique (forage, plantage, arrosage, surveillance, guidage). Le démonstrateur sert à valider les modèles de navigation, de localisation, de planification ainsi que les procédures de plantation et de surveillance de l’environnement / Land degradation directly affects over a billion hectares throughout the world. It is a threat to almost 35% of the planet’s land as well as to the means of subsistence of two billion people. Estimations of heavy financial losses are increasing year after year. The degradation of arid and semi-arid lands is a serious drawback to the development of the countries concerned. This problem is today unsolved and since a number of organizations within the international community have not found an appropriate, perennial solution, we are powerlessly witnessing the progression of this plague despite the efforts and experiments carried out all over the world. It has become extremely urgent to find solutions that are not only technical, but also social, economic and cultural.This assessment calls for action and the need to exploit different approaches based on the most recent advanced technology. Mobile robotics are a lead to explore and may well contribute to slowing down this phenomenon in the near future. This technology offers endless possibilities in many fields: healthcare, personal assistance, military, agriculture and of course the restoring of ecosystems. It will therefore be necessary to follow the evolution of this sector and observe its effects on the environment and society in general in those regions affected by the phenomenon. Our findings aim to propose a technical solution, and the more general questions regarding societal consequences are not examined; our main concern is to demonstrate and evaluate the resilience capacity of a solution based on robotic techniques. This document is part of the R-Stepps project to experiment a fleet of robots to combat land degradation and reverse the progress of desertification. Its main mission is reforestation, maintenance and surveillance of such zones. The fleet of robots is composed of various platforms, each with a specific function. By limiting each robot to one task, this will ensure their solidity and simple design
62

A linguistic and cultural analysis of localisation practices on oil and gas company websites

Umoh, Idara Enobong January 2015 (has links)
Oil and Gas companies have the inevitable need to operate in a global environment and therefore have a global reach. This thesis seeks to understand the nature and degree of localisation of the websites in this industry. This thesis introduces two notions of ‘global’, and seeks to examine the relationship between them: the first of which is the Global reach or operations of companies and the second is where a company’s communication is localised in language and cultural terms. A company can be seen to be ‘global’ in one of these two notions and it is this relationship that this thesis seeks to explore. The contribution of this thesis firstly, is that it adds to previous studies of website localisation, which have focused primarily on consumer goods and the retail industry, by examining a different kind of industry. Secondly, it takes into account the important semiotic and symbolic dimensions of language and culture when looking at localisation practices. The thesis thus contributes to the growing literature on website localisation and practices in Multinational companies. This study was carried out on 387 corporate and country specific websites of 16 Oil and Gas Companies to understand the extent and nature of their localisation practises particularly the way that language and culture are presented. The websites were studied using a qualitative and quantitative research design which involved carrying out a linguistic/semiotic analysis and a cultural analysis to give a balanced perspective of localisation practices. The conclusions of the study were that the companies operated a ‘glocal’ strategy, a combination of both a localised and a globalised (standardised) strategy. The companies had a combination of globally standardised features such as the website layouts, images, colour schemes, logos and the use of global celebrities on their websites and a limited degree of localisation where the ‘local’ is signified by local country websites, local news stories, local languages, local celebrities, images of local sights, images of company’s local office buildings and local petrol stations.
63

Drivkrafter bakom svenska fastighetsmäklarföretags lokaliseringsbeslut / The driving forces behind Swedish real estate companies localisation decision

Karlsson, Marko, Liam, Bernmarker January 2022 (has links)
The real estate agent's main task is to be the intermediary actor between seller and buyer, to this task handling of practical elements such as contract writing, access and customer contact is added. These practical elements are usually handled at the real estate companies' offices, which are often located in different places in the cities. In Helsingborg, the business climate is among one of the foremost in the country, and in comparison with the average in Skåne and the country, the real estate industry is larger in Helsingborg. In addition, there are real estate companies scattered in different places in Helsingborg, whereupon the natural question becomes why? This study therefore aims to investigate the driving forces that may lie behind the localisation decision for the real estate companies in Helsingborg. The study has used a qualitative approach where the empirical material has been obtained through semi-structured interviews that have been transcribed and then summarized in the empirical section. The selection of respondents has been goal-oriented to cover the whole of Helsingborg and gain a broader perspective. The interview questions and the analysis are based on and have been formulated according to the theoretical material on which the study is based. The results of the study show that the main driving forces behind the localisation decision for the real estate companies in Helsingborg are accessibility and visibility towards their customers. / Fastighetsmäklarens huvudsakliga uppgift är att vara den förmedlande aktören mellan säljare och köpare, till denna uppgift tillkommer hantering av praktiska moment såsom bland annat kontraktsskrivningar, tillträden och kundkontakt. Dessa praktiska moment hanteras oftast på fastighetsmäklarföretagens kontor som ofta finns lokaliserade på olika platser i städerna. I Helsingborg är företagsklimatet bland ett av de främsta i landet och i jämförelse med snittet i Skåne och riket är branschen fastighetsverksamhet större i Helsingborg. Dessutom finns fastighetsmäklarföretagen utspridda på olika platser i Helsingborg, varpå den naturliga frågan blir varför? Denna studie syftar därav till undersöka vilka drivkrafter som kan ligga bakom lokaliseringsbeslutet för fastighetsmäklarföretagen i Helsingborg. Studien har nyttjat en kvalitativ ansats där det empiriska materialet har inhämtats genom semistrukturerade intervjuer som transkriberats för att sedan blivit sammanfattade i avsnittet empiri. Urvalet av respondenter har varit målstyrt för att täcka hela Helsingborg och få ett bredare perspektiv. Intervjufrågorna och analysen bygger på och har formulerats utefter det teoretiska material som ligger till grund för studien. Studiens resultat visar på att de främsta drivkrafterna bakom lokaliseringsbeslutet för fastighetsmäklarföretagen i Helsingborg är tillgänglighet och synlighet gentemot sina kunder
64

Indoor localisation by using wireless sensor nodes

Koyuncu, Hakan January 2014 (has links)
This study is devoted to investigating and developing WSN based localisation approaches with high position accuracies indoors. The study initially summarises the design and implementation of localisation systems and WSN architecture together with the characteristics of LQI and RSSI values. A fingerprint localisation approach is utilised for indoor positioning applications. A k-nearest neighbourhood algorithm (k-NN) is deployed, using Euclidean distances between the fingerprint database and the object fingerprints, to estimate unknown object positions. Weighted LQI and RSSI values are calculated and the k-NN algorithm with different weights is utilised to improve the position detection accuracy. Different weight functions are investigated with the fingerprint localisation technique. A novel weight function which produced the maximum position accuracy is determined and employed in calculations. The study covered designing and developing the centroid localisation (CL) and weighted centroid localisation (WCL) approaches by using LQI values. A reference node localisation approach is proposed. A star topology of reference nodes are to be utilized and a 3-NN algorithm is employed to determine the nearest reference nodes to the object location. The closest reference nodes are employed to each nearest reference nodes and the object locations are calculated by using the differences between the closest and nearest reference nodes. A neighbourhood weighted localisation approach is proposed between the nearest reference nodes in star topology. Weights between nearest reference nodes are calculated by using Euclidean and physical distances. The physical distances between the object and the nearest reference nodes are calculated and the trigonometric techniques are employed to derive the object coordinates. An environmentally adaptive centroid localisation approach is proposed. Weighted standard deviation (STD) techniques are employed adaptively to estimate the unknown object positions. WSNs with minimum RSSI mean values are considered as reference nodes across the sensing area. The object localisation is carried out in two phases with respect to these reference nodes. Calculated object coordinates are later translated into the universal coordinate system to determine the actual object coordinates. Virtual fingerprint localisation technique is introduced to determine the object locations by using virtual fingerprint database. A physical fingerprint database is organised in the form of virtual database by using LQI distribution functions. Virtual database elements are generated among the physical database elements with linear and exponential distribution functions between the fingerprint points. Localisation procedures are repeated with virtual database and localisation accuracies are improved compared to the basic fingerprint approach. In order to reduce the computation time and effort, segmentation of the sensing area is introduced. Static and dynamic segmentation techniques are deployed. Segments are defined by RSS ranges and the unknown object is localised in one of these segments. Fingerprint techniques are applied only in the relevant segment to find the object location. Finally, graphical user interfaces (GUI) are utilised with application program interfaces (API), in all calculations to visualise unknown object locations indoors.
65

Étude et conception d'un système de personnalisation et d'aide fonctionnelle multi-agents permettant d'assister simultanément de manière transparente les activités de vie quotidienne de multiples personnes dans un Habitat Intelligent pour la Santé

Castebrunet, Matthieu January 2011 (has links)
The application domains of this thesis are Health Smart Homes, and the research is more precisely centered on the improvement of daily-living for cognitively impaired persons and theirs caregivers.The proposed system can observe the context of each person, personalize the environment and assist the tasks detected if they need to be. Every action of the system is as unobtrusive as possible and takes into consideration the presence of more than one person. To personalize and assist the daily-living activities of a lone person, we need to know his personal context. This context is the conjunction of the preferences and habits, the illness or impairment, the movements in the smart home and the state of the various sensor and electrical devices, and the current activities that are detected for one person. To be able to assist many persons simultaneously, we need to compute the overall conjunction of each and every person's context since every presence can influence the global context and every personal one. This complexity brings a lot of problems like the multiple person localization and identification, or the personalization and assistance of multiple persons in the same space with various activities. Those problems are even more interesting since, following an ethical choice to ensure inhabitant's privacy, this project avoid the use of some intrusive technologies.
66

Mise en oeuvre et évaluation d'un système de localisation dans un habitat intelligent

Rahal, Youcef January 2008 (has links)
Dans les sociétés occidentales, la proportion de personnes âgées est en croissance. Une des conséquences de cette évolution est l'augmentation de la prévalence des maladies dégénératives qui se traduisent souvent par l'apparition d'une déficience cognitive. Dans un contexte de ressources limitées dans les services de santé, et afin de préserver au maximum la qualité de vie de ces personnes, le maintien à domicile est une solution qui doit être privilégiée. Ceci ne peut se faire qu'en assurant un niveau d'autonomie et de sécurité suffisant dans le milieu de vie de ces personnes. Le laboratoire DOMUS vise à apporter des solutions à ce problème en concevant une maison intelligente qui peut à la fois assister ses occupants et préserver leur qualité de vie. Évidemment, l'aptitude à surveiller correctement les activités de l'occupant, et ainsi de lui fournir l'aide pertinente, dépend grandement de l'information sur la position de la personne à l'intérieur de l'habitat intelligent. Ce mémoire propose une solution afin de localiser l'occupant grâce au filtrage bayésien et à un réseau de capteurs anonymes disséminés à l'intérieur de la maison. Le système de localisation est conçu pour une personne unique dans la maison. Il peut cependant être utilisé en conjonction avec d'autres systèmes de localisation dans le cas où plusieurs personnes sont présentes. La solution est fonctionnelle dans des conditions réelles. Une expérimentation est conçue afin d'estimer avec précision sa performance et d'évaluer sa robustesse. L'expérimentation consiste en un scénario de routine quotidienne pensé pour maximiser les mouvements de l'occupant dans la maison en des activités pertinentes. Il a été exécuté par 14 sujets, un sujet à la fois. Les résultats sont satisfaisants: la précision du système excède 85% et est indépendante du profil de l'occupant. Le système fonctionne en temps réel et se comporte bien en présence de bruit.
67

Interaction of CysLT1 receptor with importin [alpha] proteins

Duta, Dana-Nicoleta January 2004 (has links)
Dans cette étude, nous avons démontré par des essais de type Pull-Down la capacité de la queue C-terminale du CysLT1 d'interagir in vitro avec les importines [alpha]1, [alpha]4 et [alpha]5. Cette interaction est comparable à celle du NLS de l'antigène grand T du SV40 et du NLS de la nucléoplasmine de Xenopus laevis avec les mêmes importines. Nos études démontrent aussi que les déterminants structuraux de l'interaction ne sont pas limités seulment au NLS: des mutations dirigées contre les résidus-clé qui forment le NLS n'ont pas empêché l'interaction entre la queue C-terminale et les importines. Nos résultats suggèrent que d'autres résidus que ceux qui forment le NLS potentiel sont impliqués dans la liaison avec les importines. Nous avons démontré pour la première fois la phosphorylation in vitro de la queue C-terminale du CysLT1 par la PKA, et que cette phosphorylation peut moduler la capacité d'interaction avec l'importine [alpha]4. Nos travaux visaient aussi l'étude de l'expression cellulaire du récepteur CysLT1 et de son comportement suite à une stimulation au LTD[indice inférieur 4] .--Résumé abrégé par UMI.
68

Modélisation non locale de l'endommagement dans les structures composites

Germain, Norbert 16 November 2006 (has links) (PDF)
De nouvelles lois de comportement ont récemment été développées afin de prédire le comportement et la rupture des composites à matrice organiques. Coupler à la méthode des éléments finis, ces lois doivent permettre de prédire la dégradation de structures en composite. Cependant, le couplage de ces lois à la méthode des éléments finis est à l'origine de défaillances (instabilités, localisation, . . .) pouvant remettre en cause les résultats obtenus. Une des solutions consiste à travailler dans un cadre thermodynamique non local. La première partie de cette thèse est consacrée à l'étude de ces méthodes originales dans un cas simplifié (matériau homogène isotrope) ainsi qu'à leur couplage avec les méthodes de résolution par longueurs d'arc et de calculs parallèles. Ensuite, des extensions de la formulation à gradient implicite, au cas des composites stratifiés, sont proposées afin de prendre en compte les spécificités de ces matériaux. Un élément fini spécifique est également développé afin de modéliser le stratifié à l'échelle mésoscopique sans explicitement mailler les plis et sans utiliser de méthodes de changement d'échelle. Enfin, une comparaison entre les résultats expérimentaux et ceux issus de simulation par éléments finis est réalisée afin d'étudier l'efficacité de ces méthodes et la nature du nouveau paramètre induit par le modèle non local.
69

Investigation of micro- and macro-phenomena in densely packed granular media using the discrete element method

Zhou, Chong January 2011 (has links)
Granular materials are in abundance in nature and are estimated to constitute over 75% of all raw materials passing through the industry. Granular or particulate solids are thus of considerable interest to many industrial sectors and research communities, where many unsolved challenges still remain. This thesis investigates the micro- and macro-phenomena in densely packed particulate systems by means of the Discrete Element Method (DEM), which is a numerical tool for analysing the internal complexities of granular material as the mechanical interactions are considered at the grain scale. It presents an alternative approach to phenomenological continuum approaches when studying localisation problems and finite deformation problems in granular materials. In order to develop a comprehensive theoretical understanding of particulate matter and to form a sound base to improve industrial processes, it is desirable to study the mechanical behaviour of granular solids subject to a variety of loading conditions. In this thesis, three loading actions were explored in detail, which are biaxial compression, rigid object penetration and progressive formation of granular piles. The roles of particle shape and contact friction in each of these loading scenarios were investigated. The resulting packing structures were compared and studied to provide a micromechanical insight into the development of contact force network which governs the collective response. The interparticle contact forces and displacements were then used to evaluate the equivalent continuum stress and strain components thus providing the link between micro- and macroscopic descriptions. The information collected from the evolution of strong contact network illustrates the underlying mechanism of force transmission and propagation. DEM simulations presented in this thesis demonstrate strong capability in predicting the bulk behaviour as well as capturing local phenomenon occurring in the system. The research first simulates a testing environment of biaxial compression in DEM, in which the phenomenon of strain localisation was investigated, with special attention given to the interpretation of underlying failure mechanism. Several key micromechanical quantities of interest were extracted to understand the bifurcation instability, such as force chains, contact orientation, particle rotation and void ratio. In the simulation of progressive formation of granular piles, a counterintuitive pressure profile with a significant pressure dip under the apex was predicted for three models under certain conditions. Both particle shape and preparation history were shown to be important in the resulting pressure distribution. During the rigid body penetration into a granular sample, the contact forces were used to evaluate the equivalent continuum stress components. Significant stress concentration was developed around the punch base which further led to successive collapse and reformation of force chains. Taking the advantage of micromechanical analysis at particle scale, two distinct bearing failure mechanisms were identified as the penetration proceeded. To further quantify the nature of strain mobilisation leading to failure, Particle Image Velocimetry (PIV) was employed to measure the deformation over small strain interval in association with shear band propagation in the biaxial test and deformation pattern in the footing test. The captured images from DEM simulation and laboratory experiments were evaluated through PIV correlation. This optical measuring technique is able to yield a significant improvement in the accuracy and spatial resolution of the displacement field over highly strained and localised regions. Finally, a series of equivalent DEM simulations were also conducted and compared with the physical footing experiments, with the objective of evaluating the capability of DEM in producing satisfactory predictions.
70

Caractérisation de la thérapie photodynamique avec le bleu de toluidine dans l'élimination sélective des cellules leucémiques de la moelle osseuse

Dussault, Sylvie January 2002 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.

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