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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.
201

Creating a Raspberry Pi-Based Beowulf Cluster

Bleeker, Ellen-Louise, Reinholdsson, Magnus January 2017 (has links)
This thesis summarizes our project in building and setting up a Beowulf cluster. The idea of the project was brought forward by the company CGI in Karlstad, Sweden. CGI’s wish is that the project will serve as a starting point for future research and development of a larger Beowulf cluster. The future work can be made by both employees at CGI and student exam projects from universities. The projects main purpose was to construct a cluster by using several credit card sized single board computers, in our case the Raspberry Pi 3. The process of installing, compiling and con- figuring software for the cluster is explained. The MPICH and TensorFlow software platforms are reviewed. A performance evaluation of the cluster with TensorFlow is given. A single Raspberry Pi 3 can perform neural network training at a rate of seven times slower than an Intel system (i5-5250U at 2.7 GHz and 8 GB RAM at 1600 MHz). The performance degraded significantly when the entire cluster was training. The precise cause of the performance degradation was not found, but is ruled out to be in software, either a programming error or a bug in TensorFlow.
202

Matériaux magnétiques et solutions innovantes de filtrage CEM pour applications aéronautiques / Magnetic materials and innovative solutions for EMC filters in avionics applications

Mesmin, Fanny 28 September 2012 (has links)
L'industrie aéronautique, dans le cadre de l'avion plus électrique, met en oeuvre le remplacement d'actionneurs pneumatiques ou hydrauliques par des actionneurs électromécaniques. Cela permet de réduire le nombre de réseaux de distribution présents dans l'avion, de faciliter la maintenance et d'améliorer le rendement. Le but final est de réduire la masse et d'améliorer l'efficacité énergétique globale d'un avion pour réduire sa consommation en carburant. Les travaux de ce mémoire de thèse s'inscrivent donc la logique de réduction de la masse des convertisseurs tout en assurant des critères de perturbations CEM (Compatibilité ElectroMagnétique). En effet, les normes CEM sont de plus en plus contraignantes, en particulier les domaines sensibles tel que l'aéronautique. Les filtres CEM sont donc de plus en plus nombreux. Dans ces filtres, les composants magnétiques occupent plus de 50 % de la place et surtout de la masse. L'objectif de cette thèse est de faire émerger des solutions innovantes, en dotant les filtres CEM passifs d'un composant magnétique unique pour les perturbations de mode conduites afin de réduire sa masse. Afin de comprendre leur fonctionnement, suite à une étude bibliographique, nous avons réalisé une étude comparative de topologies à composant magnétique unique. Nous avons développé un outil de modélisation fréquentielle du composant magnétique unique. A partir d'une modélisation <<système>> nous avons pu prendre en compte l'environnement du composant magnétique (Réseau Stabilisateur d'Impédance de Ligne (RSIL), Source de perturbations, Capacités) et une modélisation plus fine des propriétés magnétiques du composant. Grâce à un modèle gyrateur-capacité, nous avons pu prédire les performances du filtre complet dans son environnement et l'optimiser. Cette étude nous a permis de réaliser une topologie de composant magnétique unique plus compacte et plus performante que la topologie existante. Par ailleurs, nous avons démontré la faisabilité de l'intégration sur PCB (Printed Board Circuit) d'alliage nanocristallin en réalisant une autre topologie de composant unique basée sur les mêmes facteurs que la précédente mais intégrée dans un PCB. Les verrous technologiques auxquels nous avons été confrontés et les solutions que nous avons proposées pour les résoudre sont détaillés dans le mémoire. / In the context of the more electric aircraft, the industry replaces pneumatic or/and hydraulic actuators for electromechanicalactuators. The ultimate goal is to reduce the weight and improve the overall energy efficiency of an aircraft to reduce fuelconsumption. This thesis aims the mass reduction converters while providing criteria EMC interference (electromagneticcompatibility). In fact, EMC standards are becoming more stringent, particularly in sensitive areas such as aeronautics. EMCfilters are more numerous. In these filters, the magnetic components have more than 50% of the space and weigth. Theobjective of this thesis is to design innovative EMC filters solutions, using a single magnetic component, to reduce conducted disturbances (common and differential modes). Following a review of the literature, we conducted a comparative study of single magnetic component topologies. We have developed a modeling tool frequency magnetic single component. From a modeling <<system>> we have to take into account the environment of the magnetic component (Impedance Stabilization Network Line (LISN), Source disturbances and capacities) and a finer modeling of magnetic properties of component. With a gyrator-capacitor model, we could predict the performance of the complete filter in its environment and optimize it. This study has allowed us to achieve a unique magnetic topology component more compact and efficient than the existing topology. In addition, we have demonstrated the feasibility of integrating PCB (Printed Circuit Board) of nanocrystalline alloy by performing another single component topology based on the same factors as above but integrated into a PCB. The technological obstacles which we faced and solutions we have proposed to solve them are detailed in the report.
203

A control unit for a Digitizer System for the PANDA Electromagnetic Calorimeter

Borrami, Sina January 2020 (has links)
PANDA is the next generation hadron physics detector under construction at the Facility for Antiproton and Ion Research (FAIR) in Darmstadt, Germany to accurately detect and parameterize particles with kinetic energies from 1MeV to 8GeV. PANDA is a 4π detector and due to its unique shape, all the readout electronic from ADC modules, power supplies, and a controller unit is housed in the liquid-cooled crates mounted inside the detector. Therefore, the readout electronics are exposed to a high level of magnetic field and radiation. The controller unit as the critical component of the digitization system with adequate radiation resiliency governs the crate. The control unit manages power supplies, monitors the radiation damages of each ADC modules, offer a mechanism to re-program the ADC module firmware, and finally features a redundant communication for the crate over fiber optics. The purpose of this thesis is to study and design the controller unit hardware that meets the specification of the PANDA experiment.
204

Design of a Printed Circuit Board for a Sensorless Three-Phase Brushless DC Motor Control System

Castle, Joshua 01 June 2020 (has links)
The use of brushless motors has increased in recent years due to superior performance characteristics compared with alternatives. The operation of a brushless motor is dependent upon a separate controller which is often in the form of a printed circuit board. As such, the size and performance capability of the controller can restrict the performance of the overall motor control system so advancements of these controllers further the potential use of BLDC motors. This project outlines the design of a PCB based, sensorless motor controller for operation of a three-phase BLDC motor powered by a 24 V, high current external supply. Components used were selected to withstand an ambient temperature environment of 125 degrees C. The design for this PCB based motor control system was completed but fabrication and testing of the system was prevented by COVID-19 related restrictions that prohibited the use of necessary facilities and equipment. The detailed design including component selection, board layout, and software development is included in addition to a plan for fabrication and fundamental functional testing. Although no results are available for analysis to bring about any conclusions, a variety of design strategies and corresponding learnings hold the potential to be a source of valuable reference to the further study and development of future designs.
205

Automatická expoziční jednotka pro výrobu DPS / Automatic exposure unit for PCB production

Blahút, Jozef January 2017 (has links)
This diploma thesis deals with the issue of fast high-quality prototype production of printed circuit boards for the needs of the mechatronics lab. Within the scope of this thesis a prototype machine was proposed and created together with control software, which by the help of DLP projector and two stage axis allows to produce printed circuit board in relatively short period of time.
206

Návrh a konstrukce CNC routeru pro DPS / CNC router for PCB

Gerják, Rastislav January 2017 (has links)
In mechanical industry, both additive and subtractive manufacturing methods are controlled by instructions in G-code, making it possible to utilize both technologies in one modular device. Main objective is to design, construct, and calibrate multipurpose machine based on RepRap 3D printer, which will be able to use attached spindle to precisely mill light materials. Particular emphasis is given to ability to carve a pattern and drill holes in plated substrate in order to create functional PCB by incision.
207

Regulátor solárního ohřevu bazénu / Solar pool heater

Jablončík, Lukáš January 2017 (has links)
The master´s thesis deals with the design of the solar heating regulator of the swimming pool. The basis was to study the available solutions for the solar pool controllers, to define the requirements, to design the concept and the block diagram of the own thermostat. The thesis also provides a description of several for the Internet of Things. The most suitable is used to control the thermostat. The resulting thermostat regulates two power outputs for filtration and the pump, it can be set using the keyboard and graphic display. At the end of the work is practically verified functionality on the model and on the real pool with solar heating.
208

Porovnání pájecích past z pohledu spolehlivosti pájeného spoje / Solder Paste Comparison from Solder Joint Reliability Point of View

Dokoupil, Jakub January 2018 (has links)
This thesis deals with the teoretical description of the solder during reflow soldering the solder paste and describing the defects arising during this process. Practical part of the thesis describes the testing of two solder pastes with different silver content before and after the accelerated temperature cycle.
209

Nízkoteplotní bizmutové pájecí pasty / Bismuth Low Temperature Solder Pastes

Švéda, Miloš January 2019 (has links)
This master´s thesis deals with bismuth low temperature solder pastes. Describes the properties of bismuth solder pastes. It shows the process of manufacturing a printed circuit board for test. The thesis also characterizes laboratory temperature profile setting for the BiSn soldering pastes. Solder paste printing and placement 0 ohm rezistors to printed circuit boards with different surface finishes in the manufacturing plant. Setting of solder profiles for low soldering pastes in reflow oven. Testing resistence of mounted zero resistor on the test board at different aging temperature were analysed. Resistance measurement after a specified time. Testing of solder joint strenght of printed circuit boards for different surface treatments. Changes in structure wereanalysed on microsections for solder pastes.
210

Modul pro řízení stejnosměrných motorů / DC motor controller module

Duz, Aleksei January 2020 (has links)
This thesis focuses on the design and creation of control unit for DC motors drives. A principle on which the DC motor is based, a method of its control and a possibility to obtain current information about the position are briefly described in this work. After that, the different types of buses for communication with a superior system and justification of the chosen one, are presented. In the next section, there is a special emphasis on creation of the suitable driver model and a design of the elecrical schematic and PCB. The end of the thesis contains a description of commission a PCB and testing the main functions.

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