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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.
1

Χρησιμοποίηση τεχνικών δειγματοληψίας για την πρόβλεψη της συμπεριφοράς των προγραμμάτων

Τραχάνης, Γεώργιος 20 October 2010 (has links)
Το να παρατηρήσουμε τη συμπεριφορά ενός προγράμματος με τις ταχύτητες των σημερινών συστημάτων είναι μία πολύ δύσκολη εργασία όταν το μόνο που είναι διαθέσιμο είναι η κύκλο προς κύκλο εξέταση. Σκοπός ήταν η κατανόηση της φιλοσοφίας των μηχανισμών ανίχνευσης φάσεων ενός προγράμματος και στη συνέχεια η ανάπτυξη ενός τέτοιου μηχανισμού που να λειτουργεί κατά τη διάρκεια εκτέλεσης ενός προγράμματος. Η λειτουργία του μηχανισμού που αναπτύχθηκε βασίζεται στη δειγματοληψία που κάνουμε από το access stream του επεξεργαστή. Ο μηχανισμός μου προσπάθησε να προσεγγίσει το μηχανισμό ανίχνευσης φάσης BBV που είναι ο πιο αξιόπιστος που υπάρχει μέχρι τώρα. Ως εφαρμογή για τη χρησιμότητα του μηχανισμού μου, έγινε σύγκριση των miss ratio που παίρνουμε με σταθερή και με προσαρμοσμένη δειγματοληψία σ’ ένα πρόγραμμα, με βάση τη αλλαγή ή μη της φάσης ενός προγράμματος κατά τη διάρκεια της εκτέλεσης. / To observe the behavior of a program with the speeds of current systems is a very difficult task when all that is available is cycle to cycle test. The aim was to understand the philosophy of mechanisms for the detection phase of a program and then develop such a mechanism that operates during the execution of a program. The operation of the mechanism was developed based on sampling we do through the access stream of the processor. The device I tried to approach, the BBV phase detection mechanism, is the most reliable there so far. As implementation of the usefulness of the mechanism, I was comparing the miss ratio we get of a stable and of adaptive sampling in a program, based on the change or not to stage a program during execution.
2

Physiological analysis of the circatidal rhythm in the mangrove cricket, Apteronemobius asahinai / マングローブスズの概潮汐リズムの生理学的解析

Sakura, Kazuki 23 March 2021 (has links)
京都大学 / 新制・課程博士 / 博士(理学) / 甲第23042号 / 理博第4719号 / 新制||理||1676(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 沼田 英治, 教授 曽田 貞滋, 准教授 森 哲 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM
3

Análise teórica e experimental de um método interferométrico de detecção de fase óptica, auto-consistente e com elevada faixa dinâmica, aplicado à caracterização de atuadores piezoelétricos flextensionais

Menezes, João Paulo Crivellaro de [UNESP] 25 May 2009 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:22:31Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-05-25Bitstream added on 2014-06-13T18:08:24Z : No. of bitstreams: 1 menezes_jpc_me_ilha.pdf: 3284910 bytes, checksum: c8578da11e5d14cfc4d1f4eaaafb100b (MD5) / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / Atuadores piezoelétricos convertem energia elétrica em energia mecânica, sendo amplamente utilizados como transdutores de deslocamento micrométricos ou sub-micrométricos de elevada precisão. Neste trabalho, atuadores piezoelétricos flextensionais (APFs), projetados pelo método de otimização topológica, são caracterizados em termos de linearidade entre a tensão de excitação e o deslocamento gerado, bem como em termos de resposta em frequência, utilizando-se um interferômetro de Michelson homódino e em malha aberta. Interferômetros homódinos não realimentados têm seu desempenho prejudicado pelo fenômeno de desvanecimento, causado por perturbações ambientais espúrias que incidem aleatoriamente entre seus braços. Nesta dissertação, enfatizam-se métodos de demodulação de fase óptica baseados em relações envolvendo as componentes espectrais do sinal de saída do interferômetro que são imunes ao problema do desvanescimento. Dentre estes, destacam-se métodos clássicos como J1... J4, J1... J4 modificado, J1... J6 neg e J1... J6 pos. Estes métodos permitem a medição direta de deslocamentos microscópicos, sem a necessidade de qualquer procedimento de calibração. Além disso, não são afetados por instabilidades da fonte óptica, da responsividade do fotodiodo e da visibilidade das franjas de interferência. Contudo, apresentam reduzidas faixas dinâmicas de demodulação de fase. A fim de superar esta deficiência, investiga-se um método adicional de detecção direta, baseado na análise do espectro do sinal fotodetectado, exibindo todas as vantagens dos demais métodos, mas que é capaz de estender a faixa dinâmica de demodulação a valores tão elevados quanto 100 rad. Simulações computacionais são executadas com este método, levando-se em consideração o efeito do desvanecimento e tensões de ruído eletrônico do tipo 1/f, evidenciando... / Piezoelectric actuators convert electrical energy into mechanical energy, being widely used as micrometric or sub-micrometric displacement transducer of high accuracy. In this work, piezoelectric flextensional actuators (PFA’s), designed by the topology optimization method, are characterized in terms of linearity between the drive voltage and the corresponding displacement, as well as in terms of frequency response, using a homodyne, open-loop, Michelson interferometer. Homodyne interferometers without feedback have their performance spoiled by signal fading, caused by spurious environmental disturbances that occur randomly between their arms. This thesis emphasizes methods of optical phase demodulation, based on relations involving the spectral components of the interferometer output signal, which are immune to signal fading. Among these methods, it is detailed here the classical ones, such as J1... J4, modified J1... J4, J1... J6 neg e J1... J6 pos. These methods allow direct measurements of microscopic displacements, free of calibration procedures. Besides, they are not affected by optical source oscillations, photodiode responsivity and interferometric fringe visibility. However, they have reduced dynamic range for phase demodulation. In order to overcome this, this work investigates an additional method for direct detection, based on spectral analysis drawback of the photodetected signal. The method has all the advantages of the others, but it is able to span its demodulation dynamic range to values as high as 100 rad. Numerical simulations are done using this method (considering the signal fading and the 1/f electronic noise voltage), showing its viability to characterize PFA’s. Experiments are performed in laboratory, involving tests with different PFA’s. The method validation is carried out with the aid of an electrooptic intensity modulator, whose phase characteristics can... (Complete abstract click electronic access below)
4

Photolithographic surface functionalization for spatio-temporally controlled protein immobilization

Bhagawati, Maniraj 27 January 2012 (has links)
Exploiting the functional diversity of proteins for fundamental research and biotechnological applications requires their functional organization into micro- and nanostructures while preserving their functional integrity to the highest possible level. My PhD research aimed to establish generic techniques based on photolithography which could be used to control the spatial as well as temporal organization of recombinantly expressed proteins on surfaces. My thesis describes in detail four strategies that I developed for achieving this goal. In the first approach a photo-induced Fenton reaction was used to selectively destroy tris(nitrilotriacetic acid) (tris-NTA) moieties on a surface. UV-irradiation through a photomask allowed localized photo-destruction and targeting of His-tagged proteins to non-irradiated regions. Photo-destruction could also be achieved by scanning selected regions with the UV laser of a confocal laser scanning microscope (CLSM) thus allowing flexible creation and modification of protein patterns. The second strategy was based on the photosensitive nitroveratryloxycarbonyl (NVOC) protection group, which was used to cage amine groups on a surface. Sequential uncaging by UV-irradiation through a photomask followed by reactions with biotin and coenzyme A was used to pattern streptavidin and ybbR-tagged proteins into microstructures. In the third approach a photo-fragmentable Histidine peptide was used to block tris-NTA surfaces against binding of His-tagged proteins. UV-irradiation through a photomask or by using a UV laser in a CLSM cleaved the peptide into short fragments which quickly dissociated from the surface due to loss in multivalency. His-tagged proteins could be efficiently targeted into irradiated regions even from a complex cell lysate. Sequential uncaging and immobilization allowed the construction of multiplexed protein patterns with a high degree of temporal control. The fourth strategy used combined peptide tags comprising of a His-tag as well as a Halo- or ybbR-tag to achieve rapid covalent immobilization of recombinant fusion proteins on surfaces functionalized with specific ligands. In combination with a photo-fragmentable histidine peptide as described above, stable spatio-temporal organization of proteins carrying these combined tags was possible. The techniques developed in this thesis enabled the photolithographical micropatterning of recombinant proteins carrying specific peptide or protein tags on surfaces in a functional manner. Owing to the generic nature of immobilization strategies, coupled with the ease of patterning, highly versatile applications of these methods both in fundamental research as well as bio-technological and analytical applications can be envisioned.
5

Design and Testing of a Prototype High Speed Data Acquisition System for Nasa

Vijayendra, Vishwas Tumkur 01 January 2011 (has links) (PDF)
Modern radar and signal processing applications require data acquisition systems capable of high-speed analog data reception and processing. These systems need to support sophisticated signal processing algorithms and reliable high-speed interfaces. The objective of this project is to develop a prototype of a state of the art data acquisition system to aid NASA’s Surface Water and Ocean Topography (SWOT) mission. The SWOT mission aims at monitoring water levels of various water bodies to predict and avoid any catastrophic events. The principal instrument is a Ka-band Radar Interferometer (KaRIN) that is used for the measurement of water levels. The collected data need to be digitized and processed using an FPGA based-data acquisition system housed in a satellite. The scope of this project involves the design, implementation and test of a high-speed printed circuit board (PCB) that serves as the prototype data acquisition system. A lot of emphasis is placed on layout design, as the PCB needs to support data rates up to three Giga samples per second. The goal of this research is to provide Jet Propulsion Laboratory (JPL), NASA with a prototype version of the high- speed acquisition system that can be integrated with the KaRIN system in future.
6

Análise teórica de uma nova técnica de processamento de sinais interferométricos baseada na modulação triangular da fase óptica /

Takiy, Aline Emy. January 2010 (has links)
Orientador: Cláudio Kitano / Banca: Ricardo Tokio Higuti / Banca: Luiz Antonio Perezi Marçal / Resumo: Neste trabalho estuda-se a interferometria laser, a qual constitui uma técnica adequada para determinar grandezas físicas com sensibilidade extremamente elevada. Basicamente, no interferômetro óptico, a informação a respeito do dispositivo sob teste é inserida na fase da luz. Utilizando-se o fotodiodo, promove-se a transferência de informação, do domínio óptico para o elétrico, no qual pode ser demodulada usando-se as várias técnicas disponíveis na literatura para detectar sinais modulados em fase. Ênfase é dada a um novo método de demodulação de fase óptica auto-consistente e de grande sensibilidade. Neste método, utiliza- se a modulação dada por uma forma de onda triangular e é baseado na análise do espectro do sinal fotodetectado, sendo capaz de estender a faixa dinâmica de demodulação a valores tão elevados quanto às dos métodos clássicos. Simulações dinâmicas computacionais de interferômetros ópticos são executadas em Simulink juntamente com este método, levando-se em consideração tensões de ruído eletrônico do tipo ruído branco, evidenciando a eficiência do método quando comparados com dados teóricos obtidos em Matlab. A validação experimental do método é realizada com o auxílio de um modulador eletro-óptico de amplitudes, cujas características de fase podem ser previstas analiticamente. Trata-se de um sensor polarimétrico baseado em cristal de Niobato de Lítio, em que a diferença de fase óptica induzida pela tensão elétrica aplicada pode ser determinada através de análise espectral, tal como o novo método descrito neste trabalho. Um interferômetro de Michelson homódino de baixo custo é implementado e a eficiência do novo método de demodulação de fase óptica é avaliada através de testes com atuadores e manipuladores piezoelétricos flextensionais, cujas características de linearidade são conhecidas... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: In this work, has been done a study the laser interferometer, which is a technique for determining physical quantities with extremely high sensitivity. Basically, in the optical interferometer, information about the device under test modulates the phase of light. Using a photodiode, promotes the transfer of information from the optical domain for the electric, which can be demodulated using the various techniques available in literature to detect modulated signals in phase. Emphasis is given to a new method of phase demodulation of optical self-consistent and high sensitivity. The method employs a linear modulation given by a triangular waveform, and is based on analysis of the spectrum of the photodetected signal, being able to extend the dynamic range of the demodulation values as high as the classical methods. Dynamic computational simulations of optical interferometers are implemented in Simulink with this method, taking into account strains of electronic noise like white noise, indicating the efficiency of the method compared with theoretical data obtained in Matlab workspace. The experimental validation of the method is performed with the aid of an electro- optic amplitude modulator, whose phase characteristics can be analytically predicted. This is a polarimetric sensor based on lithium niobate crystal, in which the optical phase difference induced by electric voltage can be determined by spectral analysis, using new method described in this work. A low cost homodyne Michelson interferometer is implemented and the efficiency of the new method of optical phase demodulation is evaluated by testing with piezoelectric flextensional actuators whose characteristics of linearity are well known.The experimental results agree with theoretical analysis and reveal this method is more efficient than the classical methods / Mestre
7

Local optical phase detection probes with an application to a high speed boundary layer

Perret, Matias Nicholas 01 August 2016 (has links)
This thesis presents the continued development of micro optical phase detection instrumentation capable of measuring void fraction, interfacial area density, interfacial velocity and bubble sizes and their application to measurements in a high speed boundary layer. The instrumentation consists of micro sized sapphire tipped probes tailored to measure in the two-phase flow of air bubbles in water. Probe tips with geometries intended to maximize field life while minimizing intrusiveness were designed, fabricated and characterized. The characterization revealed that the active region of a probe tip can go beyond the highly sensitive 45 degree tip. Controlling the active length of the tips can be achieved through a combination of taper angles and 45 degree tip size, with larger tips having shorter active lengths. The full scale bubbly flow measurements were performed on a 6 m flat bottom survey boat. The aforementioned quantities were measured on bubbles naturally entrained at the bow of the boat. Probes were positioned at the bow of the boat, near the entrainment region and at the stern where the bubbles exit after having interacted with the high shear turbulent boundary layer. Experiments were conducted in fresh water, at the Coralville Lake, IA, and salt water, at the St. Andrews Bay and Gulf Coast near Panama City, FL. The results indicate that the bubbles interact significantly with the boundary layer. At low speeds, in fresh water, bubble accumulation and coalescence is evident by the presence of large bubbles at the stern. At high speeds, in both fresh and salt water, bubble breakup dominates and very small bubbles are produced near the hull of the boat. It was observed that salt water inhibits coalescence, even at low boat speeds. Void fraction was seen to increase with boat speeds above 10 knots and peaks near the wall. Bubble velocities show slip with the wall at all speeds and exhibit large RMS fluctuations, increasing near the wall.
8

Full-scale two-phase flow measurements using optical probes on Athena II research vessel

Johansen, James Paul 01 May 2010 (has links)
Measurements of gas volume fraction, bubble velocity, chord length and bubble size distributions were performed in the research vessel Athena II operating in Saint Andrew Bay in the gulf coast near Panama City, FL. Double tipped sapphire optical local phase-detection probes were used to acquire indicator functions downstream of the breaking bow wave, behind the masker and at the stern. These indicator functions were also taken at different depths, distances from the hull, operating speeds and headings respect to the waves. The data processing includes the computation of velocity of individual bubbles and chord lengths, resulting in chord length distributions. These chord length distributions are used to obtain bubble size distributions using a novel procedure described in detail. Uncertainty analysis is performed for gas volume fraction, average bubble velocity and chord length. The results indicate that air entrainment increases with ship speed and sailing against the waves at all positions. The bow wave exhibits unsteady breaking that creates bubble clouds, which were characterized and identified by signal processing. At the stern a very strong dependence of bubble size with depth was found, with evidence that bubbles smaller than 500 micrometers are transported through the bottom of the hull and reach the transom. The roller present at the transom, the associated strong unsteadiness and bubble entrainment are well captured, as indicated by the stern results, showing the frothy nature of the upper layer.
9

Grid phase and harmonic detection using cascaded delayed signal cancellation technique

Wang, Yifei Unknown Date
No description available.
10

Análise teórica e experimental de um método interferométrico de detecção de fase óptica, auto-consistente e com elevada faixa dinâmica, aplicado à caracterização de atuadores piezoelétricos flextensionais /

Menezes, João Paulo Crivellaro de. January 2009 (has links)
Orientador: Cláudio Kitano / Banca: Aparecido Augusto de Carvalho / Banca: Demartonne Ramos França / Resumo: Atuadores piezoelétricos convertem energia elétrica em energia mecânica, sendo amplamente utilizados como transdutores de deslocamento micrométricos ou sub-micrométricos de elevada precisão. Neste trabalho, atuadores piezoelétricos flextensionais (APFs), projetados pelo método de otimização topológica, são caracterizados em termos de linearidade entre a tensão de excitação e o deslocamento gerado, bem como em termos de resposta em frequência, utilizando-se um interferômetro de Michelson homódino e em malha aberta. Interferômetros homódinos não realimentados têm seu desempenho prejudicado pelo fenômeno de desvanecimento, causado por perturbações ambientais espúrias que incidem aleatoriamente entre seus braços. Nesta dissertação, enfatizam-se métodos de demodulação de fase óptica baseados em relações envolvendo as componentes espectrais do sinal de saída do interferômetro que são imunes ao problema do desvanescimento. Dentre estes, destacam-se métodos clássicos como J1... J4, J1... J4 modificado, J1... J6 neg e J1... J6 pos. Estes métodos permitem a medição direta de deslocamentos microscópicos, sem a necessidade de qualquer procedimento de calibração. Além disso, não são afetados por instabilidades da fonte óptica, da responsividade do fotodiodo e da visibilidade das franjas de interferência. Contudo, apresentam reduzidas faixas dinâmicas de demodulação de fase. A fim de superar esta deficiência, investiga-se um método adicional de detecção direta, baseado na análise do espectro do sinal fotodetectado, exibindo todas as vantagens dos demais métodos, mas que é capaz de estender a faixa dinâmica de demodulação a valores tão elevados quanto 100 rad. Simulações computacionais são executadas com este método, levando-se em consideração o efeito do desvanecimento e tensões de ruído eletrônico do tipo 1/f, evidenciando... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Piezoelectric actuators convert electrical energy into mechanical energy, being widely used as micrometric or sub-micrometric displacement transducer of high accuracy. In this work, piezoelectric flextensional actuators (PFA's), designed by the topology optimization method, are characterized in terms of linearity between the drive voltage and the corresponding displacement, as well as in terms of frequency response, using a homodyne, open-loop, Michelson interferometer. Homodyne interferometers without feedback have their performance spoiled by signal fading, caused by spurious environmental disturbances that occur randomly between their arms. This thesis emphasizes methods of optical phase demodulation, based on relations involving the spectral components of the interferometer output signal, which are immune to signal fading. Among these methods, it is detailed here the classical ones, such as J1... J4, modified J1... J4, J1... J6 neg e J1... J6 pos. These methods allow direct measurements of microscopic displacements, free of calibration procedures. Besides, they are not affected by optical source oscillations, photodiode responsivity and interferometric fringe visibility. However, they have reduced dynamic range for phase demodulation. In order to overcome this, this work investigates an additional method for direct detection, based on spectral analysis drawback of the photodetected signal. The method has all the advantages of the others, but it is able to span its demodulation dynamic range to values as high as 100 rad. Numerical simulations are done using this method (considering the signal fading and the 1/f electronic noise voltage), showing its viability to characterize PFA's. Experiments are performed in laboratory, involving tests with different PFA's. The method validation is carried out with the aid of an electrooptic intensity modulator, whose phase characteristics can... (Complete abstract click electronic access below) / Mestre

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