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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.
31

Injection de fautes par impulsion laser dans des circuits sécurisés / Fault injections by laser impulsion in secured microcontrollers

Sarafianos, Alexandre 17 September 2013 (has links)
De tout temps, l’Homme s’est vu contraint de protéger les fruits de sa créativité et les domaines concernant sa sécurité. Ses informations sont souvent sensibles, dans les relations politiques et commerciales notamment. Aussi, la nécessité de les protéger en les rendant opaques au regard d’adversaires ou de concurrents est vite survenue. Depuis l’Antiquité, les procédés de masquages et enfin de cryptages furent nombreux. Les techniques de protection, depuis l’époque industrielle n’ont fait que croître pour voir apparaître, durant la seconde guerre mondiale, l’archétype des machines électromécaniques (telle l’Enigma), aux performances réputées inviolables. De nos jours, les nouveaux circuits de protection embarquent des procédés aux algorithmes hyper performants. Malgré toutes ces protections, les produits restent la cible privilégiée des « pirates » qui cherchent à casser par tous les moyens les structures de sécurisation, en vue d’utilisations frauduleuses. Ces « hackers » disposent d’une multitude de techniques d’attaques, l’une d’elles utilise un procédé par injections de fautes à l’aide d’un faisceau laser. Dès le début de ce manuscrit (Chapitre I), l’état de l’art de l’injection de fautes sera développé, en se focalisant sur celles faite à l’aide d’un faisceau laser. Ceci aidera à bien appréhender ces procédés intrusifs et ainsi protéger au mieux les microcontrôleurs sécurisés contre ces types d’attaques. Il est nécessaire de bien comprendre les phénomènes physiques mis en jeu lors de l’interaction entre une onde de lumière cohérente, tels les lasers et le matériau physico-chimique qu’est le silicium. De la compréhension de ces phénomènes, une modélisation électrique des portes CMOS sous illumination laser a été mise en oeuvre pour prévoir leurs comportements (chapitre II). De bonnes corrélations ont pu être obtenues entre mesures et simulations électrique. Ces résultats peuvent permettre de tester la sensibilité au laser de portes CMOS au travers de cartographies de simulation. De cette meilleure compréhension des phénomènes et de ce simulateur mis en place, de nombreuses contre-mesures ont été imaginées. Les nouvelles techniques développées, présentées dans ce manuscrit, donnent déjà des pistes pour accroître la robustesse des circuits CMOS contre des attaques laser. D’ores et déjà, ce travail a permis la mise en oeuvre de détecteurs lasers embarqués sur les puces récentes, renforçant ainsi sensiblement la sécurité des produits contre une attaque de type laser. / From time immemorial, human beings have been forced to protect the fruits of their creativity and ensure the security of their property. This information is very often strategic, in particular in political and commercial relationships. Also the need to protect this information by keeping it concealed in regards to enemies or competitors soon appeared. From ancient times, the methods used for masking and eventually encrypting information were numerous. Protection techniques have only advanced grown since the industrial era and have led to the precursor of electro-mechanic machines (such as the famous Enigma machine). Nowadays, new protection circuitry embeds very efficient algorithms. Despite these protections, they remain a prime target for « attackers » who try to break through all means of securing structures, for fraudulent uses. These « attackers » have a multitude of attack techniques. One of them uses a method of fault injections using a laser beam. From the beginning (Chapter I), this manuscript describes the state of the art of fault injections, focusing on those made using a laser beam. It explains these intrusive methods and provides information on how to protect even the most secure microcontrollers against these types of attacks. It is necessary to understand the physical phenomena involved in the interaction between a coherent light wave, such as lasers, and the physicochemical material that makes up a microcontroller. To better understanding these phenomena, an electrical modeling of CMOS gates under laser illumination was implemented to predict their behavior (Chapter II). Good correlations have been obtained between measurements and electrical simulation. These results can be used to test the laser sensitivity of CMOS gates through electrical cartographies. Due to the better understanding of the phenomena and the developed simulator, many countermeasures have been developed. The techniques presented in this manuscript offer new possibilities to increase the robustness of CMOS circuits against laser attacks. This work has already enabled the implementation of efficient counter-measures on embedded laser sensors and significantly enhanced product security against different laser attacks.
32

Telemetria de dados e imagens para plataforma autônoma para coleta de dados hidrológicos / Image and data telemetry for an autonomous water quality monitoring platform

Alex Ayres Stavarengo 22 August 2006 (has links)
A aquisição de dados das variáveis químicas e físicas da água de lagos e reservatórios é de extrema importância. Monitorando a qualidade da água distribuída e consumida em nossas cidades estamos protegendo o nosso recurso natural mais valioso e conseqüentemente nossas próprias vidas. Esse monitoramento na atualidade ainda se realiza de forma bastante convencional e trabalhosa. Esta dissertação apresenta o desenvolvimento de um sistema de telemetria de dados e vídeo completo entre uma plataforma autônoma para coleta de dados hidrológicos e uma estação de trabalho em terra. Este sistema fará uma composição com outros projetos já desenvolvidos nesta área de pesquisa, como a embarcação convencional utilizada como plataforma autônoma com seus motores, sensores e atuadores; a sonda de coleta de dados, responsável pela aquisição das variáveis químicas e físicas da água; sistema de posicionamento, que utiliza um GPS e bússola eletrônica para orientação, atuando e coletando dados dos sensores da embarcação; e sistema de gerenciamento, responsável por definir e orientar quais os pontos de coletas a serem pesquisados. Foram desenvolvidos algoritmos de comunicação entre os dispositivos de hardware existentes, efetivou-se a comunicação da plataforma autônoma e do microcomputador na estação terrestre através de um enlace de rádio freqüência, desenvolveu-se um programa visual que permite o acompanhamento do estado dos sensores/atuadores do sistema em terra em tempo mínimo e habilita para o usuário um controle remoto de navegação da embarcação autônoma de forma manual e completa se ocorrer a falha de algum equipamento de posicionamento. O programa armazena todas as variáveis referentes ao processo de coleta em um banco de dados, permitindo a análise e comparação das diferentes medições realizadas em diferentes períodos. / The data acquisition of the water chemical and physical variables in lakes and reservoirs is of extreme importance. Monitoring the quality of water supplied and consumed in our cities we are protecting the most valuable of our natural resources, and consequently our own lifes. Monitoring data quality, still in our days, is done in a conventional and hard manner. This work presents the development of a data and video telemetry system between an autonomous platform for water monitoring and a ground base. This system will complement the following already developed projects in this area, the autonomous platform constructed from a conventional boat with its engines, sensors and actuators; the data collecting probe, responsible for the acquisition of the water chemical and physical variables; the positioning system based on GPS and an electronic compass, responsible for navigation to the data collecting points in the reservoir. Communication algorithms between all the hardware were developed, radio frequency links were used to transmit data between the ground and the autonomous platform. A visual software application, that allows to visualize the state off the system variables, was developed. A remote control mode of the platform allows full manual navigation control of the platform, being of extreme importance in case of system crash. The visual software application developed allows to store all the important research variables in a data bank, allowing further analysis of the collected data.
33

Telemetria de dados e imagens para plataforma autônoma para coleta de dados hidrológicos / Image and data telemetry for an autonomous water quality monitoring platform

Stavarengo, Alex Ayres 22 August 2006 (has links)
A aquisição de dados das variáveis químicas e físicas da água de lagos e reservatórios é de extrema importância. Monitorando a qualidade da água distribuída e consumida em nossas cidades estamos protegendo o nosso recurso natural mais valioso e conseqüentemente nossas próprias vidas. Esse monitoramento na atualidade ainda se realiza de forma bastante convencional e trabalhosa. Esta dissertação apresenta o desenvolvimento de um sistema de telemetria de dados e vídeo completo entre uma plataforma autônoma para coleta de dados hidrológicos e uma estação de trabalho em terra. Este sistema fará uma composição com outros projetos já desenvolvidos nesta área de pesquisa, como a embarcação convencional utilizada como plataforma autônoma com seus motores, sensores e atuadores; a sonda de coleta de dados, responsável pela aquisição das variáveis químicas e físicas da água; sistema de posicionamento, que utiliza um GPS e bússola eletrônica para orientação, atuando e coletando dados dos sensores da embarcação; e sistema de gerenciamento, responsável por definir e orientar quais os pontos de coletas a serem pesquisados. Foram desenvolvidos algoritmos de comunicação entre os dispositivos de hardware existentes, efetivou-se a comunicação da plataforma autônoma e do microcomputador na estação terrestre através de um enlace de rádio freqüência, desenvolveu-se um programa visual que permite o acompanhamento do estado dos sensores/atuadores do sistema em terra em tempo mínimo e habilita para o usuário um controle remoto de navegação da embarcação autônoma de forma manual e completa se ocorrer a falha de algum equipamento de posicionamento. O programa armazena todas as variáveis referentes ao processo de coleta em um banco de dados, permitindo a análise e comparação das diferentes medições realizadas em diferentes períodos. / The data acquisition of the water chemical and physical variables in lakes and reservoirs is of extreme importance. Monitoring the quality of water supplied and consumed in our cities we are protecting the most valuable of our natural resources, and consequently our own lifes. Monitoring data quality, still in our days, is done in a conventional and hard manner. This work presents the development of a data and video telemetry system between an autonomous platform for water monitoring and a ground base. This system will complement the following already developed projects in this area, the autonomous platform constructed from a conventional boat with its engines, sensors and actuators; the data collecting probe, responsible for the acquisition of the water chemical and physical variables; the positioning system based on GPS and an electronic compass, responsible for navigation to the data collecting points in the reservoir. Communication algorithms between all the hardware were developed, radio frequency links were used to transmit data between the ground and the autonomous platform. A visual software application, that allows to visualize the state off the system variables, was developed. A remote control mode of the platform allows full manual navigation control of the platform, being of extreme importance in case of system crash. The visual software application developed allows to store all the important research variables in a data bank, allowing further analysis of the collected data.
34

Design And Realization Of A Step Motor Driver With Micro-stepping Capability

Hizal Ates, Emel 01 May 2011 (has links) (PDF)
Step motors are motion control mechanisms that convert digital pulses into mechanical shaft rotation. They provide high precision positioning and repeatability of movement without a closed loop control, which is preferable for industrial applications in which accurate positioning control is needed. In this thesis, design and realization of a step motor driver will be performed using micro-stepping, which is based on controlling the current of each winding of the motor continuously and solves noise and resonance problems as well as providing an increase in accuracy and resolution.
35

Ανάπτυξη εκπαιδευτικού συστήματος (Η/W, S/W) για δικτυακές εφαρμογές, βασισμένου σε μικροελεγκτή AVR

Παπαπαύλου, Χρήστος 30 April 2014 (has links)
Στην παρούσα διπλωματική εργασία σχεδιάστηκε και υλοποιήθηκε ένα δίκτυο πραγματικού χρόνου με σκοπό την διασύνδεση μιας ομάδας μικροελεγκτών. Bασισμένος στο δίκτυο, αναπτύχθηκε ένας δικτυακός bootloader για μικροελεγκτές AVR και σχεδιάστηκε desktop εφαρμογή για την διεπαφή του χρήστη με το δίκτυο. Απώτερος σκοπός του εγχειρήματος αυτού είναι η χρήση του συστήματος από φοιτητές στο πλαίσιο των μαθημάτων μικροϋπολογιστών και συγκεκριμένα να διευκολύνει την ανάπτυξη δικτυακών εφαρμογών με μικροελεγκτές. / At this diploma thesis a real-time network protocol was designed and implemented in order to interconnect a group of microcontrollers. Based at this protocol, a network bootloader was developed for AVR microcontrollers and a desktop application for the interface of the user with the network was developed. Ultimate goal of this work is to be used from students of microcomputer courses and specifically to facilitate the development of network applications with microcontrollers.
36

Μελέτη και κατασκευή φορτιστή συσσωρευτών, με διόρθωση του συντελεστή ισχύος, ελεγχόμενου από μικροελεγκτή

Καλαρίδης, Στυλιανός 18 June 2014 (has links)
Η παρούσα διπλωματική εργασία πραγματεύεται το σχεδιασμό και την κατασκευή ενός μετατροπέα ανόρθωσης και υποβιβασμού τάσης, με διόρθωση του συντελεστή ισχύος. Η χρήση αυτού του μετατροπέα προορίζεται για τη φόρτιση των μπαταριών ενός ηλεκτροκίνητου οχήματος. Η εργασία αυτή εκπονήθηκε στο Εργαστήριο Ηλεκτρομηχανικής Μετατροπής Ενέργειας του Τμήματος Ηλεκτρολόγων Μηχανικών και Τεχνολογίας Υπολογιστών της Πολυτεχνικής Σχολής του Πανεπιστημίου Πατρών. Κύριος σκοπός της διπλωματικής εργασίας είναι η κατασκευή μιας τριφασικής ανορθωτικής διάταξης υποβιβασμού τάσης η οποία θα πληρεί τις προδιαγραφές περί αρμονικών που θεσπίζονται από τους διεθνείς κανονισμούς. Η δυνατότητα λειτουργίας υπό μοναδιαίο συντελεστή ισχύος πηγάζει από τη μεθοδολογία ελέγχου του μετατροπέα ο οποίος παράλληλα θα πρέπει να επιτελεί το έργο ενός φορτιστή μπαταριών προσφέροντας τη δυνατότητα ελέγχου του ρεύματος και της τάσης εξόδου και προσαρμόζοντας τη λειτουργία του στο εκάστοτε προφίλ φόρτισης των μπαταριών τις οποίες διαχειρίζεται. Αρχικά αναλύεται η σημασία της διόρθωσης του συντελεστή ισχύος στα σύγχρονα ηλεκτρικά συστήματα και παρουσιάζονται τόσο μεθοδολογίες ελέγχου όσο και ανορθωτικές διατάξεις για λειτουργία υπό μοναδιαίο συντελεστή ισχύος. Στη συνέχεια γίνεται μια σύντομη αναφορά στις μπαταρίες ως μέσο αποθήκευσης ενέργειας, παρουσιάζονται μέθοδοι και διατάξεις φόρτισης συσσωρευτών ενώ παράλληλα αναλύονται θέματα που αφορούν την ταχύτητα φόρτισης και την διάρκεια ζωής των μπαταριών με τελικό στάδιο την παρουσίαση των μπαταριών του ηλεκτροκίνητου οχήματος του εργαστηρίου και την επιλογή του κατάλληλου προφίλ φόρτισής με βάση τα τεχνικά χαρακτηριστικά και τις προδιαγραφές τους από τον κατασκευαστή. Το επόμενο βήμα είναι η παρουσίαση του τριφασικού μετατροπέα, που θα υλοποιεί το προφίλ φόρτισης που έχει επιλεγεί, αλλά και της μεθοδολογίας ελέγχου για επίτευξη ημιτονοειδούς ρεύματος εισόδου. Τόσο ο ηλεκτρονικός μετατροπέας ισχύος ως φορτιστής μπαταριών όσο και το κύκλωμα ελέγχου κλειστού βρόχου προσομοιώνονται στο λογισμικό Simulink του Matlab. Επίσης περιγράφονται η ανάλυση, ο σχεδιασμός και η κατασκευή όλων των ηλεκτρικών και ηλεκτρονικών κυκλωμάτων που απαιτούνται για την ορθή λειτουργία του μετατροπέα και παρουσιάζεται η λογική λειτουργίας του μικροϋπολογιστικού συστήματος που συντονίζει τον έλεγχο. Τέλος πραγματοποιούνται οι πειραματικές δοκιμές προκειμένου να διαπιστωθεί η ορθή λειτουργία του συνολικού συστήματος που κατασκευάστηκε αλλά και για να διαπιστωθούν τυχούσες αποκλίσεις μεταξύ θεωρίας και πράξης. / This diploma thesis deals with the design and construction of a buck type, unity power factor rectifier intended for electric vehicle battery charging. The work was conducted in the Electromechanical Energy Conversion Laboratory, placed at the Department of Electrical and Computer Engineering of the University of Patras. The main purpose of this thesis is to construct a three-phase buck-type rectifier which meets with the requirements for low input current harmonics established by international regulations. The ability to operate under unity power factor derives from the control method of the converter. The converter will be also performing the task of a battery charger. Therefore, the overall system should be able to provide control of the output voltage and current and adjust its operation to the charging profile and the type of the battery used. Initially, the significance of power factor correction in modern electrical systems is mentioned and control methods as well as the most commonly used rectifiers for unity power factor operation are presented. Then, a brief reference to the batteries as energy storage means is made and charging methods and devices are presented. Certain issues related to charging speed and battery life are approached. The final stage is the presentation of the batteries installed in the electric vehicle of the Laboratory and the selection of the appropriate charging profile based on the technical specifications of the manufacturer. The next step is the presentation of the three-phase rectifier which realizes the selected charging profile and the control method in order to achieve sinusoidal input currents .Both the electronic power converter as a battery charger and the closed-loop control circuit are simulated using Simulink of Matlab .The analysis, design and the construction of all electrical and electronic circuits required for the proper operation of the converter is described and the programming logic of the microcontroller that coordinates the control is presented. Finally, experimental tests are performed in order to check the proper functioning of the overall constructed system and detect any deviations between theory and practice.
37

Υλοποίηση συστήματος ασύρματων αισθητήρων για έλεγχο δομικής ακεραιότητας μέσω ακουστικής εκπομπής

Παλληκάρης, Αλέξιος 01 August 2014 (has links)
Ο Έλεγχος Δομικής Ακεραιότητας (ΕΔΤ) μέσω Ακουστικής Εκπομπής, αποτελεί ένα σημαντικό εργαλείο της μηχανικής στην έγκαιρη διάγνωση δομικών σφαλμάτων και στην αύξηση της διάρκειας ζωής κτηρίων. Οι σύγχρονες εφαρμογές συστημάτων ΕΔΤ χαρακτηρίζονται από μεγάλο κόστος εφαρμογής και συντήρησης. Χρησιμοποιώντας νέες τεχνολογίες ολοκληρωμένων συστημάτων χαμηλής κατανάλωσης ισχύος, ασύρματης επικοινωνίας, καθώς επίσης και τεχνικών ψηφιακής επεξεργασίας σημάτων και αναγνώρισης προτύπων, μπορεί να δημιουργηθεί ένα σύστημα ΕΔΤ φθηνό και αποδοτικό. Στόχος μας σε αυτή την διπλωματική είναι η υλοποίηση ενός συστήματος ασύρματων αισθητήρων, ικανών να επιτελέσουν έλεγχο δομικής ακεραιότητας μέσω ακουστικής εκπομπής, χρησιμοποιώντας μικροελεγκτές LPC2148 και πομποδέκτες nRF24L01. / Structural health monitoring with acoustic emission techniques is an important engineering tool in the diagnosis of structural faults. Modern applications of SHM systems are difficult to implement and cost inefficient. By using new integrated systems technologies, wireless communications, coupled with better techniques in signal processing and pattern recognition, a much more cheap and efficient SHM system may be build. Our target in this thesis, is to implement a wireless sensor system, capable of SHM with acoustic emission, by using LPC2148 microcontrollers and nRF24L01 transceivers.
38

"A Computer for the Rest of You": Human-Computer Interaction in the Eversion

Macpherson, Shaun Gordon 25 April 2014 (has links)
With the increasing ubiquity of networked “smart” devices that read and gather data on the physical world, the disembodied, cognitive realm of cyberspace has become “everted,” as such technologies migrate the communications networks and data collection of the Internet into the physical world. Popular open-source “maker” practices—most notably the practice of physical computing, which networks objects with digital environments using sensors and microcontrollers—increasingly push human-computer interaction (HCI) into the physical domain. Yet such practices, as political theorists and some philosophers of technology argue, bypass the very question of subjectivity, instead lauding the socioeconomic liberation of the individual afforded by open-source hardware practices. What is missing across these discourses is a technocultural framework for studying the material ways that everted technologies articulate subjects. I argue that examining the various, contradictory forms of interface that emerge from physical computing provides such a framework. To support this claim, I focus on several case studies, drawn from popular physical computing practices and communities, and analyze the particular ways that these devices articulate subjectivity. I conclude by linking my technocultural framework with various feminist theories of boundary transgression and hybridity, and end by suggesting that, in an everted landscape, the subject is politically constituted by a proximity to present time and space. / Graduate / 0585 / shaunmac@uvic.ca
39

"A Computer for the Rest of You": Human-Computer Interaction in the Eversion

Macpherson, Shaun Gordon 25 April 2014 (has links)
With the increasing ubiquity of networked “smart” devices that read and gather data on the physical world, the disembodied, cognitive realm of cyberspace has become “everted,” as such technologies migrate the communications networks and data collection of the Internet into the physical world. Popular open-source “maker” practices—most notably the practice of physical computing, which networks objects with digital environments using sensors and microcontrollers—increasingly push human-computer interaction (HCI) into the physical domain. Yet such practices, as political theorists and some philosophers of technology argue, bypass the very question of subjectivity, instead lauding the socioeconomic liberation of the individual afforded by open-source hardware practices. What is missing across these discourses is a technocultural framework for studying the material ways that everted technologies articulate subjects. I argue that examining the various, contradictory forms of interface that emerge from physical computing provides such a framework. To support this claim, I focus on several case studies, drawn from popular physical computing practices and communities, and analyze the particular ways that these devices articulate subjectivity. I conclude by linking my technocultural framework with various feminist theories of boundary transgression and hybridity, and end by suggesting that, in an everted landscape, the subject is politically constituted by a proximity to present time and space. / Graduate / 2015-04-21 / 0585 / shaunmac@uvic.ca
40

Softwaremethoden zur Senkung der Verlustenergie in Microcontrollersystemen /

Hildebrandt, Ralf. January 2007 (has links)
Zugl.: Dresden, Techn. Universiẗat, Diss., 2007.

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