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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.
21

Geração de espécies reativas de oxigênio e neuroinflamação induzidas por enucleação ocular no sistema visual de ratos. / Reactive oxygen species generation and neuroinflammation induced by ocular enucleation in the rat visual system.

Marina Sorrentino Hernandes 29 April 2011 (has links)
O modelo de enucleação ocular em roedores é frequentemente empregado para o estudo dos efeitos da desaferentação de estruturas retinorrecipientes. Avaliamos a geração de espécies reativas de oxigênio (EROs), no colículo superior (CS) e núcleo geniculado lateral dorsal do tálamo (GLD) após enucleação ocular. A oxidação da dihidroetidina revelou o aumento da geração de EROs no CS e no GLD após a lesão. Os resultados de RT-PCR revelaram aumento da expressão gênica de Nox 2 em ambas as estruturas avaliadas. Em contrapartida, observou-se aumento da expressão gênica de Nox 1 e 4 apenas no CS. Com a finalidade de avaliarmos o envolvimento de EROs no remodelamento estrutural após a lesão, animais foram tratados com apocinina e ensaios de imuno-histoquímica foram realizados utilizando-se anticorpos contra neurofilamentos (NFs) e proteínas associadas a microtúbulos-2 (MAP-2). Os resultados revelaram que a enucleação ocular produz um aumento na imunorreatividade para NFs e MAP-2 no CS e GLD, o que foi atenuado pelo tratamento com apocinina. / Unilateral ocular enucleation represents a useful model to study visual system plasticity. We evaluated the reactive oxygen species (ROS) generation in the main visual relays of the mammalian brain, namely the superior colliculus (SC) and the dorsal lateral geniculate nucleus (DLG), after ocular enucleation. Dihydroethidium oxidation revealed increased ROS generation in SC and DLG. ROS generation was decreased by the Nox inhibitors DPI and apocynin. Real-time PCR results revealed that Nox 2 was upregulated in both retinorecipient structures after deafferentation, whereas Nox 1 and Nox 4 were upregulated only in the SC. To evaluate the role of ROS in structural remodeling after the lesions, apocynin was given to enucleated rats and immunohistochemistry was conducted for markers of neuronal remodeling into SC and DLG. Immunohistochemical data showed that ocular enucleation produces an increase of neurofilament and microtubule-associated protein-2 immunostaining in both SC and DLG, which was markedly attenuated by apocynin treatment.
22

Vision system i utmanande miljöer / Vision systems in challenging environments : Developing guidelines for implementation of vision systems in the metal casting industry

Bohlin, Oskar, Hawil, Steven January 2023 (has links)
Companies strive to optimize their processes to increase productivity, efficiency, and quality in the production system. The complexity of different operations in a production system can vary, the level of complexity impacts the automation approach. The requirements of an automated solution increases with the level of complexity. A vision system is a type of automation solution which can improve the quality inspection process in many companies where the inspection process is performed manually. A challenge with implementing a vision system in different industries is that there are no general solutions. Depending on the requirements of an industry, the implementation of a vision system needs to be tailored to suit that industry. In this thesis, a case study is conducted in a foundry setting where empirical data is gathered through observations and interviews conducted with several departments. Nine parameters are identified which can affect the performance of a vision system in a metal casting environment. The identified parameters are analysed using relevant literature to find possible solutions. The result of the analysis is a set of guidelines which can be used when implementing vision systems in the metal casting industry and aims to mitigate possible negative effects of each parameter. A conceptual layout of a vision cell used to inspect cylinder heads based on the guidelines is also presented.
23

Prototype an integrated 3D camera in a gripper

Barón Suárez, Julia, Roldán Cobos, Almudena January 2023 (has links)
In today´s interconnected world, our lives are inextricably linked with technology, a trend set to continue. Robots, pivotal to global industry and commerce, have made an significant impact since their inception. This report proposes an approach to enhance robotic functionality by integrating a 3D camera into a gripper´s case. This integration improves robotic functions and refines how robots perform tasks, mirroring human-like capabilities. This paper outlines the design and creation process of the prototype, including considerations for its development. Extensive research was conducted on current grippers, 3D vision systems, and available 3D cameras. Moreover, the design process using CAD tools is shown and explained in detail, followed by the creation of a physical prototype through 3D printing. The study underscores the significance of such advancements in shaping the future of robotics. It emphasizes that the innovative design of these products will play a crucial role in advancing automation technology.
24

The Use of Image and Point Cloud Data in Statistical Process Control

Megahed, Fadel M. 18 April 2012 (has links)
The volume of data acquired in production systems continues to expand. Emerging imaging technologies, such as machine vision systems (MVSs) and 3D surface scanners, diversify the types of data being collected, further pushing data collection beyond discrete dimensional data. These large and diverse datasets increase the challenge of extracting useful information. Unfortunately, industry still relies heavily on traditional quality methods that are limited to fault detection, which fails to consider important diagnostic information needed for process recovery. Modern measurement technologies should spur the transformation of statistical process control (SPC) to provide practitioners with additional diagnostic information. This dissertation focuses on how MVSs and 3D laser scanners can be further utilized to meet that goal. More specifically, this work: 1) reviews image-based control charts while highlighting their advantages and disadvantages; 2) integrates spatiotemporal methods with digital image processing to detect process faults and estimate their location, size, and time of occurrence; and 3) shows how point cloud data (3D laser scans) can be used to detect and locate unknown faults in complex geometries. Overall, the research goal is to create new quality control tools that utilize high density data available in manufacturing environments to generate knowledge that supports decision-making beyond just indicating the existence of a process issue. This allows industrial practitioners to have a rapid process recovery once a process issue has been detected, and consequently reduce the associated downtime. / Ph. D.
25

Modelos de negócio para geradores incentivados atuando no ambiente de contratação livre do Brasil. / Business models for incentivized generator acting in the freee market electricity of Brazil.

Guimarães, Matheus Thomé Albano 26 October 2016 (has links)
Made available in DSpace on 2017-07-10T16:41:35Z (GMT). No. of bitstreams: 1 Dissert Matheus Albano.pdf: 3597659 bytes, checksum: 7090061e73fc33981468aa62be2a4560 (MD5) Previous issue date: 2016-10-26 / The Incentivized Generator (IG) is a small agent that acts on the retail segment of the Electricity Market (EM) in Brazil. It receives incentives, as discounts on wire rates, when negotiates its energy either directly with special costumers or indirectly through a retail trader. The dynamic behavior of this agent on the complex EM results in an extremely uncertain environment for itself, hindering the growth of the retail market. Thus, the purpose of the study is to identify, characterize and describe the forms of GI relationship, putting them in the form of a business model, showing how you can create, provide and receive value of the medium. For the development of the business model, we propose the use of methodologies Busmod and Business Model Generation, the first by the great relationship with the proposed objective and the second by most of the application. The interrelations of the generator encouraged with other agents as well as the value changes and the uncertainties associated with the commercialization process are identified from a systemic approach to generator operation encouraged the ACL. These relationships are classified into three broad groups, physical, financial and institutional relationships. The analysis was segmented to consider the period of study and of implantation and operation. In this way it is possible to clearly understand the marketing process and the environment in which the GI is inserted, as well as the characteristics necessary for the elaboration of business models. / O Gerador Incentivado (GI) é um agente de pequeno porte que atua no segmento varejista do Mercado de Energia Elétrica (MEE) do Brasil. O mesmo recebe incentivo, na forma de descontos nas tarifas de fio, ao negociar sua energia diretamente com os consumidores especiais ou através de uma comercializadora. A dinâmica que envolve o complexo MEE resulta em um ambiente extremamente incerto para a atuação desse agente, dificultando o crescimento do mercado varejista. Assim, o propósito do trabalho é identificar, caracterizar e descrever as formas de relacionamento do GI, colocando-as na forma de um modelo de negócio, mostrando de que forma é possível criar, fornecer e receber valor do meio. Para a elaboração do modelo de negócio, é proposta a utilização das metodologias Busmod e Business Model Generation. As inter-relações do gerador incentivado com os demais agentes, assim como as trocas de valor e as incertezas associadas ao processo de comercialização, são identificadas a partir de uma abordagem sistêmica da atuação do gerador incentivado no ACL. Essas relações são classificadas em três grandes grupos, relações físicas, financeiras e institucionais. A análise foi segmentada para considerar o período de estudo e de implantação e operação. Desse modo é possível compreender de forma clara o processo de comercialização e o ambiente no qual está inserido o GI, assim como as características necessárias para a elaboração de modelos de negócio.
26

Optimisation du fonctionnement d'un générateur de hiérarchies mémoires pour les systèmes de vision embarquée / Optimization of the operation of a generator of memory hierarchies for embedded vision systems

Hadj Salem, Khadija 26 April 2018 (has links)
Les recherches de cette thèse portent sur la mise en oeuvre des méthodes de la rechercheopérationnelle (RO) pour la conception de circuits numériques dans le domaine du traitementdu signal et de l’image, plus spécifiquement pour des applications multimédia et de visionembarquée.Face à la problématique de “Memory Wall”, les concepteurs de systèmes de vision embarquée,Mancini et al. (Proc.DATE, 2012), ont proposé un générateur de hiérarchies mémoiresad-hoc dénommé Memory Management Optimization (MMOpt). Cet atelier de conception estdestiné aux traitements non-linéaires afin d’optimiser la gestion des accès mémoires de cestraitements. Dans le cadre de l’outil MMOpt, nous abordons la problématique d’optimisationliée au fonctionnement efficace des circuits de traitement d’image générés par MMOpt visantl’amélioration des enjeux de performance (contrainte temps-réel), de consommation d’énergieet de coût de production (contrainte d’encombrement).Ce problème électronique a été modélisé comme un problème d’ordonnancement multiobjectif,appelé 3-objective Process Scheduling and Data Prefetching Problem (3-PSDPP), reflétantles 3 principaux enjeux électroniques considérés. À notre connaissance, ce problème n’apas été étudié avant dans la littérature de RO. Une revue de l’état de l’art sur les principaux travauxliés à cette thèse, y compris les travaux antérieurs proposés par Mancini et al. (Proc.DATE,2012) ainsi qu’un bref aperçu sur des problèmes voisins trouvés dans la littérature de RO,a ensuite été faite. En outre, la complexité de certaines variantes mono-objectif du problèmed’origine 3-PSDPP a été établie. Des approches de résolution, y compris les méthodes exactes(PLNE) et les heuristiques constructives, sont alors proposées. Enfin, la performance de cesméthodes a été comparée par rapport à l’algorithme actuellement utilisé dans l’outil MMOpt,sur des benchmarks disponibles dans la littérature ainsi que ceux fournis par Mancini et al.(Proc.DATE, 2012).Les solutions obtenues sont de très bonne qualité et présentent une piste prometteuse pouroptimiser les performances des hiérarchies mémoires produites par MMOpt. En revanche, vuque les besoins de l’utilisateur de l’outil sont contradictoires, il est impossible de parler d’unesolution unique en optimisant simultanément les trois critères considérés. Un ensemble debonnes solutions de compromis entre ces trois critères a été fourni. L’utilisateur de l’outilMMOpt peut alors décider de la solution qui lui est la mieux adaptée. / The research of this thesis focuses on the application of the Operations Research (OR)methodology to design new optimization algorithms to enable low cost and efficient embeddedvision systems, or more generally devices for multimedia applications such as signal and imageprocessing.The design of embedded vision systems faces the “Memory Wall” challenge regarding thehigh latency of memories holding big image data. For the case of non-linear image accesses, onesolution has been proposed by Mancini et al. (Proc. DATE 2012) in the form of a software tool,called Memory Management Optimization (MMOpt), that creates an ad-hoc memory hierarchiesfor such a treatment. It creates a circuit called a Tile Processing Unit (TPU) that containsthe circuit for the treatment. In this context, we address the optimization challenge set by theefficient operation of the circuits produced by MMOpt to enhance the 3 main electronic designcharacteristics. They correspond to the energy consumption, performance and size/productioncost of the circuit.This electronic problem is formalized as a 3-objective scheduling problem, which is called3-objective Process Scheduling and Data Prefetching Problem (3-PSDPP), reflecting the 3 mainelectronic design characteristics under consideration. To the best of our knowledge, this problemhas not been studied before in the OR literature. A review of the state of the art, including theprevious work proposed by Mancini et al. (Proc.DATE, 2012) as well as a brief overview onrelated problems found in the OR literature, is then made. In addition, the complexity of someof the mono-objective sub-problems of 3-PSDPP problem is established. Several resolutionapproaches, including exact methods (ILP) and polynomial constructive heuristics, are thenproposed. Finally, the performance of these methods is compared, on benchmarks available inthe literature, as well as those provided by Mancini et al. (Proc.DATE, 2012), against the onecurrently in use in the MMOpt tool.The results show that our algorithms perform well in terms of computational efficiency andsolution quality. They present a promising track to optimize the performance of the TPUs producedby MMOpt. However, since the user’s needs of the MMOpt tool are contradictory, such aslow cost, low energy and high performance, it is difficult to find a unique and optimal solutionto optimize simultaneously the three criteria under consideration. A set of good compromisesolutions between these three criteria was provided. The MMOpt’s user can then choose thebest compromise solution he wants or needs.
27

Design, modeling and control of a convertible mini airplane having four tiliting rotors / Conception, modélisation et commande d'un drone convertible à quatre hélices pivotantes

Flores Colunga, Gerardo Ramón 31 October 2014 (has links)
Cette thèse étudie certains problèmes plus importants dans le sens de guidage, navigation et contrôle présentés dans une catégorie particulière de mini véhicules aériens (MVA) : le MVA convertible avec des ailes fixes et disques pendulaires. Cet aéronef est capable de changer sa configuration de vol, du vol stationnaire au vol palier et vice versa, au moyen d’une manœuvre de transition. Motivé par des applications civiles, on étudie théoriquement et expérimentalement les principes de contrôle en fonction de Lyapunov pour les dynamiques présentées dans le MVA convertible. Des résultats de convergence asymptotique sont obtenus sur l’enveloppe de vol complet du véhicule : d’un vol vertical à basse vitesse à un vol vers l’avant à grande vitesse. Cette thèse est divisée en quatre parties principales : l’étude de 1) les aéronefs à voilure fixe ; 2) le quadrirotor (avion équipe de quatre moteurs) ; 3) l’aéronef convertible ; 4) les applications de vision en utilisant l’aéronef convertible. Dans la première partie, un principe de contrôle en fonction de Lyapunov est développé pour diriger un mini véhicule aérien à voilure fixe tout au long d’un chemin d’accès souhaité. En outre, un générateur de chemin d’accès est proposé. Le résultant de la stratégie du contrôle donne une convergence globale du chemin actuel du MVA au chemin d’accès souhaité. Dans la deuxième partie, un contrôle en fonction de Lyapunov à l’aide de la théorie de la perturbation du singulier est proposé et appliqué sur la dynamique du MVA. En effet, dans cette partie on a abordé le problème diagnostic et la détection de pannes fault detection and diagnosis (FDD) pour un quadrirotor. Dans la troisième partie une nouvelle stratégie de contrôle pour effectuer la transition d’un avion convertible entre le mode avion et le mode hélicoptère, et vice versa, est présenté. L’analyse est effectuée pour le modèle longitudinal du PVHAT (Planar Vertical Helicopter-Airplane Transition) aéronef, lequel est un avion ayant disques pendulaires afin de réaliser la manœuvre de transition. L’algorithme de contrôle de boucle fermée qui en résulte, est prouvé être globalement asymptotiquement stable. Finalement, dans la quatrième partie de cette thèse, le problème de l’estimation et suivi d’un chemin à l’aide de vision système embarqué dans l’avion PVHAT est résolu. La stabilité globale exponentielle de la position sous-système ainsi que le contrôleur de commutation est démontrée. Des simulations illustratives et résultats expérimentaux sont obtenus sur plusieurs plateformes expérimentales développées dans cette thèse, pour évaluer l’applicabilité des principes contrôle proposés et mettre en valeur les mérites de l’approche. / This thesis studies some of the most relevant problems in the sense of guidance,navigation and control presented in a particular class of mini aerial vehicles (MAV) : the convertible MAV with fixed wings and tilting rotors. This aircraft is able to change its flight configuration from hover to level flight and vice-versaby means of a transition maneuver. Motivated by civilian applications, we theoretically and experimentally study Lyapunov-based control laws for dynamics presented in the convertible MAV. Results of asymptotic convergence are obtained over the complete flight envelope of the vehicle : from low-speed vertical flight through high-speed forward flight. We have divided this thesis in four main parts : the study of 1) the fixed-wingaircraft; 2) the quadrotor; 3) the convertible aircraft and 4) vision applications by using the convertible aircraft. In a first part, a Lyapunov-based controllaw is developed to steer a fixed wing mini aerial vehicle along a desired path. Furthermore a path generator is proposed. The resulting control strategy yields global convergence of the current path of the MAV to the desired path. In a second part, a Lyapunov-based control using singular perturbation theory is proposed and applied on dynamics of the MAV. Furthermore, in this part we address the problem of fault detection and diagnosis (FDD) for a quad-rotor. In the third part a new control strategy for the transition between airplane and helicopter mode, and vice versa, in convertible planes is presented. The analysis is carried out for the longitudinal model of the PVHAT (Planar VerticalHelicopter-Airplane Transition) aircraft, which is an airplane having tilting rotors in order to achieve the transition maneuver. The resulting closed loop control algorithm is proved to be globally asymptotically stable. Finally in thefourth part of this thesis the problem of estimation and tracking of a road using avision embedded system in the PVHAT aircraft is solved. The global exponential stability of the position subsystem together with the switching controller is demonstrated. Illustrative simulations and experimental results obtained on several experimental platforms developed in this thesis, assess the implementability of the proposed control laws and highlight the merits of the approach.
28

Optimized information processing in resource-constrained vision systems. From low-complexity coding to smart sensor networks

MORBEE, MARLEEN 14 October 2011 (has links)
Vision systems have become ubiquitous. They are used for traffic monitoring, elderly care, video conferencing, virtual reality, surveillance, smart rooms, home automation, sport games analysis, industrial safety, medical care etc. In most vision systems, the data coming from the visual sensor(s) is processed before transmission in order to save communication bandwidth or achieve higher frame rates. The type of data processing needs to be chosen carefully depending on the targeted application, and taking into account the available memory, computational power, energy resources and bandwidth constraints. In this dissertation, we investigate how a vision system should be built under practical constraints. First, this system should be intelligent, such that the right data is extracted from the video source. Second, when processing video data this intelligent vision system should know its own practical limitations, and should try to achieve the best possible output result that lies within its capabilities. We study and improve a wide range of vision systems for a variety of applications, which go together with different types of constraints. First, we present a modulo-PCM-based coding algorithm for applications that demand very low complexity coding and need to preserve some of the advantageous properties of PCM coding (direct processing, random access, rate scalability). Our modulo-PCM coding scheme combines three well-known, simple, source coding strategies: PCM, binning, and interpolative coding. The encoder first analyzes the signal statistics in a very simple way. Then, based on these signal statistics, the encoder simply discards a number of bits of each image sample. The modulo-PCM decoder recovers the removed bits of each sample by using its received bits and side information which is generated by interpolating previous decoded signals. Our algorithm is especially appropriate for image coding. / Morbee, M. (2011). Optimized information processing in resource-constrained vision systems. From low-complexity coding to smart sensor networks [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/12126 / Palancia
29

Architectures et apports de systèmes de vision light-field pour la vision par ordinateur / Designs and contributions of light-field vision systems for computer vision

Riou, Cécile 13 December 2017 (has links)
Cette thèse traite des caméras light-field en tant que caméra ayant des capacités 3D. Les images brutes, acquises avec ces systèmes, sont généralement inexploitables directement. L’obstacle majeur concernant l'utilisation de ces caméras réside dans la complexité du traitement des images acquises. Cette thèse vise à dépasser ces limitations en s'intéressant aux dispositifs multi-vues et multi-caméras. De plus, comme l'un des domaines d'application envisagé est la vision industrielle, les images sont acquises en lumière naturelle afin de conserver la possibilité d'effectuer des traitements conventionnels par vision sur les images. Le travail de thèse repose sur trois axes : l'étude et la conception optique de systèmes light-field multi-caméras et multi-vues, le calibrage de ces dispositifs et le développement d’algorithmes et enfin leur mise en application pour montrer les intérêts de ces caméras dans divers domaines. / This thesis deals with light-field cameras as cameras having 3D capacities. The raw images. acquired with these systems, are generally unusable directly. The main obstacle about their use lies in the complex processing of the recorded images. This thesis aims to overcome these limitations by focusing on multi-views and multi-camera devices. Morcover, as one of the application domains is the industrial vision, the images are acquired in natural lightning in order to conserve the possibility to make conventional treatments by vision on the images. The work is based on three axis: the study and'the optical desien of light-field systems, the calibration of these devices and the development of algorithms to show the intercsts of these cameras in various fields.

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