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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

Synchronisation Behaviour of Viscoelastically Coupled Self-Sustained Oscillators as Models for Oscillations of Premature Cardiomyocytes

Stein, Sebastian 16 October 2017 (has links)
No description available.
202

Contribution à la réalisation d’un oscillateur push-push 80GHz synchronisé par un signal subharmonique pour des applications radars anticollisions

Ameziane El Hassani, Chama 06 May 2010 (has links)
Ce travail de thèse s’inscrit dans le cadre d’un projet Français « VéLo » qui est une collaboration entre l’industriel STMicroelectronics et plusieurs laboratoires dont les laboratoires IMS-bordeaux et LAAS. Le but du projet est de concevoir un prototype de radar anticollision millimétrique. Dans ce travail un synthétiseur de fréquence est implémenté. Ce dernier sera intégré dans la chaine de réception du démonstrateur. Une étude bibliographique des architectures classiques de système de radiocommunication a été réalisée. Des exemples d’architectures rencontrées dans le domaine millimétrique ont été étudiés.L’objet principal de cette thèse est l’étude des oscillateurs synchronisés par injection ILO. L’objectif est de réaliser un oscillateur verrouillé par injection qui sera piloté par un oscillateur de fréquence plus basse possédant des caractéristiques de stabilité et de bruit meilleures.Dans ce travail de thèse, le mécanisme de verrouillage des oscillateurs par injection a été décrit. Un modèle de synchronisation par injection série, basé sur la théorie de Huntoon Weiss et inspiré du travail de Badets réalisé sur les oscillateurs synchrones verrouillés par injection parallèle, est proposé. La théorie établie a permis d’exprimer la plage de synchronisation en fonction de la topologie utilisée et des composants de la structure. La validité de la théorie a été évaluée par la simulation de la structure. Les résultats présentés montrent une bonne concordance entre la simulation et la théorie et permettent de valider le principe de synchronisation par injection. La faisabilité de l’intégration d’un ILO millimétrique synchronisé par l’harmonique d’un signal de référence de fréquence plus basse a été démontrée expérimentalement. Le synthétiseur de fréquence est réalisé en technologie BiCMOS 130nm pour des applications millimétriques de STMicroelectronics. Ce dernier opère dans une plage de 2GHz autour de la fréquence 82,5GHz. Les performances en bruit du synthétiseur sont satisfaisantes. Le bruit de phase de l’ILO recopie celui du signal injecté. Les équipements de mesures utilisés, le bruit de phase de l’oscillateur atteint des valeurs inférieures à -110dBc/Hz à 1MHz de la porteuse. / This thesis is a part of a French project "VELO". The project is collaboration between STMicroelectronics and several laboratories including IMS-Bordeaux and LAAS laboratories. The aim of this project is to achieve a prototype of millimeter anti-collision radar. In this work a frequency synthesizer is implemented. This circuit will be incorporated in the reception chain of the demonstrator. A bibliographical study of classical architecture was completed. Examples of architectures encountered in the millimeter frequency range have been studied. The purpose of this thesis is to study the phenomena of synchronization in oscillators. The objective is to design an injection locked oscillator ILO driven by another oscillator, the second oscillator operates at lower frequency and offers better stability and noise characteristics.In this thesis, the injection locking mechanism of the oscillators has been described. A model of synchronization by series injection is proposed. The model is based on the theory of Huntoon and Weiss and inspired by Badets’ work performed on parallel injection. The theory expresses the synchronized frequency range depending on the used topology and the values of the components. The validity of the theory was evaluated by simulation. The results show good agreement between simulation and theory and validate the principle of synchronization by injection.The feasibility of a millimeter ILO synchronized by the harmonic of a reference signal operating at lower frequency has been demonstrated experimentally. The synthesizer was implemented in BiCMOS technology for 130nm applications millimeter of STMicroelectronics. The oscillator operates at 82.5 GHz and performs a frequency range of 2GHz. The noise performance of the synthesizer is satisfactory. The phase noise of the ILO depends on the reference phase noise, and reaches values of -110dBc/Hz at 1MHz from the carrier frequency.
203

Analyse des limites de résolution fréquentielle des capteurs vibrants de type MEMS / Analysis of the frequency resolution limits of MEMS vibrating sensors

Papin, Guillaume 18 December 2014 (has links)
Les capteurs de type MEMS (Micro Electro Mechanical Systems) sont des microsystèmes mettant en œuvre différents domaines de la physique (électronique, mécanique, chimie, optique,...) et permettant de mesurer différentes grandeurs physiques (accélération, pression, température...). Parmi ces micro-capteurs, les MEMS vibrants se caractérisent par leur structure présentant un micro-résonateur mis en vibration à sa fréquence de résonance et la variation de cette fréquence est représentative du mesurande. Cette thèse s'intéresse principalement à analyser et identifier les limites de résolution fréquentielle de ces capteurs vibrants en effectuant une modélisation multiphysique. Dans un premier temps, nous avons modélisé le comportement multiphysique d'un capteur MEMS vibrant en détaillant trois types de transduction (piézoélectrique, électrostatique et optique). La seconde partie a permis de valider les équations développées en se basant sur les simulations sous Cadence (langage multiphysque Verilog-A) et en les validant par des mesures expérimentales. La dernière partie traite de l'optimisation d'un micro-accéléromètre de type VIA (Vibrating Inertial Accelerometer) et l'étude de l'annulation des non linéarités permettant d'améliorer la résolution d'un capteur MEMS vibrant / MEMS (Micro Electro Mechanical Systems) sensors are micro-systems implementing various fields of physics (electronical, mechanical, chemical, optical, ...) and measuring various physical quantities (acceleration, pressure, temperature ...). The vibrating MEMS are characterized by a micro-resonator vibrating at its resonant frequency. The frequency variation is proportional to the measurand. This thesis is concerned with analyzing and identifying the frequency resolution limits of these vibrating sensors by performing multiphysics modeling. The first step is to model the multiphysics behavior of a vibrating MEMS sensor with three transduction types (piezoelectrical, electrostatical and optical). Secondly, the equations developed are validated, based on simulations with Cadence (multiphysique language Verilog-A) and their comparaison with experimental measurements. The last section presents the micro-accelerometer VIA (Vibrating Inertial Accelerometer) optimization and the nonlinearities cancellation study for improving the resolution of vibrating MEMS sensor
204

Arrays of magnetic nanostructures : a dynamical and structural study by means of X-ray experiments

Heldt, Georg January 2014 (has links)
The work in this PhD thesis covers two strands of x-ray experiments: firstly, the characterisation of large arrays of dense structures by means of x-ray scattering, and, secondly, the investigation of hybrid anisotropy square structures with x-ray microscopy. The ability to accurately characterise large arrays of nanoscale magnetic structures is a key requirement for both scientific understanding and technological advance such as bit patterned recording media (BPM). In this work small angle x-ray scattering (SAXS) was investigated as a characterisation technique for large arrays of patterned structures. Dense arrays of magnetic nanostructures were prepared on x-ray transparent membranes and measured. The SAXS data was then modelled to obtain structure parameters such as the mean structure diameter, the diameter distribution and the mean position variance with statistical significance. Arrays (500 x 500 μm2) of nominally uniform nanostructures with centre-to-centre distances between 250 nm-50 nm were structurally characterised and compared to structure diameters obtained by optical scanning electron microscopy measurements. The mean structure diameter was found to be between 39 nm-15nm and agree within the errors with the diameter obtained from SEM measurements. This work provides accurate data on the distribution (variance) of nanostructure sizes which is key for modelling these arrays for applicationin BPM. In the second part of the work, the static and dynamic properties of patterned hybrid anisotropy square structures ([Co/Pd]-Py) were investigated by using time-resolved scanning transmission X-ray microscopy (STXM). In these patterned structures the magnetisation in the layers change both in magnitude and direction and gives rise to interesting new domain configurations. The reciprocal interaction between magnetic vortices in the Py layer and locally circular stripe domains in the Co/Pd was investigated and a mutual domain imprint between the layer was observed. In dynamic excitation experiments the precession of the vortex core is studied and showed good agreement with micromagnetic simulations made by Hrkac and Bryan. As demonstrated patterned hybrid anisotropy square structures have promising magnetic properties with potential applications in data storage (vortex switching) or spintronics (vortex oscillators).
205

Modeling System Bath Hamiltonian with a Machine Learning Approach / 機械学習的アプローチによる系・熱浴ハミルトニアンのモデリング

Ueno, Seiji 24 September 2021 (has links)
京都大学 / 新制・論文博士 / 博士(理学) / 乙第13434号 / 論理博第1576号 / 新制||理||1682(附属図書館) / 京都大学大学院理学研究科 / (主査)教授 谷村 吉隆, 教授 林 重彦, 教授 渡邊 一也 / 学位規則第4条第2項該当 / Doctor of Science / Kyoto University / DGAM
206

Investiční strategie pro obchodování akcií na americkém trhu / Investment Strategies for Stock Trading in the US Market

Janičko, Adam January 2017 (has links)
This master thesis aims at creating automatic trading system, which consists of design, implementation, optimization and testing, on U.S stock market. The algorithm is based on trend identification using falling and rising price minimums and maximums over a certain time interval. Based on the identified trend, the algorithm places buy or sell orders on the stock exchange, which parameters are calculated using Keltner Channel and Stochastic Oscillator indicators.
207

Přijímač signálů DRM / DRM signal receiver

Mik, Šimon January 2011 (has links)
The master’s thesis deals with the design of DRM (Digital Radio Mondiale) receiver. The block diagram of receiver was chosen and particular blocks were theoretically analyzed. After that followed design and production of each block. The synthesizer was programmed and the receiver properties were verified. The last part of thesis deals with real receiving of DRM broadcast.
208

Návrh smyčky fázového závěsu / Design of the PLL

Hejlek, Pavel January 2013 (has links)
This work is dealing with phase lock loop design. In the theoretical part is principal description. In the practical part is detailed mathematical description, choice of various blocks, design calculation and optimalization of final solution. Designed solution is simulated and final result are commented.
209

Elektronicky řiditelné aktivní prvky k realizaci oscilátorů a funkčních generátorů / Electronically adjustable active elements for the realization of oscillators and function generators

Bokůvka, Tomáš January 2014 (has links)
This thesis is focused on the design, analysis and realization of new oscillator and generator circuits using electronically adjustable active elements. In the opening discussion the aspects of distribution, proposal, properties and oscillation conditions of generators and oscillators are theoretically described. Next, there are presented some electronically adjustable active elements which appear to be suitable for construction of the oscillators and generators. This covers in particular the Operational Transconductance Amplifier OTA, Voltage Control Amplifier VCA and Digitally Adjustable Current Amplifier DACA. Using these elements the six oscillators and two functional generators are presented. Simulation results and design methods are included. Next part is focused on practical realization and measurement. At the end of the thesis the measurement and simulation results are discussed and compared.
210

Aktivní obvodové prvky s proudovými vstupy a výstupy a jejich aplikace / Current-Input Current-Output Active Circuit Elements and their Applications

Vávra, Jiří January 2012 (has links)
The thesis deals with definitions of new current- or mixed-mode circuit elements and their implementations and applications. Based on the analysis of the state-of-the-art, novel application circuits employing the above circuit elements are designed. For the purpose of the experimental verification, the active elements are implemented via commercial integrated circuits, and their applications are simulated via PSpice. The application circuits are focused on frequency filters, rectifiers, oscillators, and current-copy circuits. Selected applications are analyzed with respect on real influences, and measurements on circuit prototypes are also performed.

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