Dissertations / Theses: 'High Speed Probes'

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Hadizadeh, Rameen. "Novel probe structures for high-speed atomic force microscopy." Thesis, Georgia Institute of Technology, 2009. http://hdl.handle.net/1853/37203.

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Atomic Force Microscopy (AFM) has become an indispensable metrology tool for nanoscale surface characterization. Today, research and industry demand faster and more accurate metrology and these demands must be met expediently. Traditional AFM cantilevers and associated actuators (i.e. piezoelectric) are limited in regards to actuation speed and resonance frequency presenting the user with an undesired trade-off of speed versus resolution. Based on a pre-existing technology known as the FIRAT (Force Sensing Integrated Readout and Active Tip) AFM probe, this work aims to remedy actuation and response issues by implementing a cantilever-on-cantilever probe as well as a novel seesaw probe. Both cases implement electrostatic actuation, eliminating the need for piezoelectrics while demonstrating large - micron scale - actuation and sensitive displacement detection. These new probe designs can potentially demonstrate a wide bandwidth frequency response (e.g. 100 kHz) ideal for high-speed video-rate imaging. Unlike traditional AFM cantilevers, this is realized by mechanically coupling two physically separate structures to provide a soft resonator sensor atop a stiff actuator structure. Common surface-micromachining techniques are utilized to solve the logistical challenge of fabricating these stacked structures. By manipulating the viscous damping and mechanical mode coupling it becomes feasible to attain the aforementioned desired dynamic characteristics.

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Perret, Matias Nicholas. "Local optical phase detection probes with an application to a high speed boundary layer." Diss., University of Iowa, 2016. https://ir.uiowa.edu/etd/2129.

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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.

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Pollard, Mark Robert. "The development of novel force probes, high speed imaging and electronics to enhance optical trapping experiments." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.544018.

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Wu, Xiaohua. "Field simulation and calibration in external electro-optic sampling /." *McMaster only, 1996.

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Jeong, Younkoo. "HIGH SPEED ATOMIC FORCE MICROSCOPY." The Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1236701109.

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Lebel, David. "Statistical inverse problem in nonlinear high-speed train dynamics." Thesis, Paris Est, 2018. http://www.theses.fr/2018PESC2189/document.

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Ce travail de thèse traite du développement d'une méthode de télédiagnostique de l'état de santé des suspensions des trains à grande vitesse à partir de mesures de la réponse dynamique du train en circulation par des accéléromètres embarqués. Un train en circulation est un système dynamique dont l'excitation provient des irrégularités de la géométrie de la voie ferrée. Ses éléments de suspension jouent un rôle fondamental de sécurité et de confort. La réponse dynamique du train étant dépendante des caractéristiques mécaniques des éléments de suspension, il est possible d'obtenir en inverse des informations sur l'état de ces éléments à partir de mesures accélérométriques embarquées. Connaître l'état de santé réel des suspensions permettrait d'améliorer la maintenance des trains. D’un point de vue mathématique, la méthode de télédiagnostique proposée consiste à résoudre un problème statistique inverse. Elle s'appuie sur un modèle numérique de dynamique ferroviaire et prend en compte l'incertitude de modèle ainsi que les erreurs de mesures. Les paramètres mécaniques associés aux éléments de suspension sont identifiés par calibration Bayésienne à partir de mesures simultanées des entrées (les irrégularités de la géométrie de la voie) et sorties (la réponse dynamique du train) du système. La calibration Bayésienne classique implique le calcul de la fonction de vraisemblance à partir du modèle stochastique de réponse et des données expérimentales. Le modèle numérique étant numériquement coûteux d'une part, ses entrées et sorties étant fonctionnelles d'autre part, une méthode de calibration Bayésienne originale est proposée. Elle utilise un métamodèle par processus Gaussien de la fonction de vraisemblance. Cette thèse présente comment un métamodèle aléatoire peut être utilisé pour estimer la loi de probabilité des paramètres du modèle. La méthode proposée permet la prise en compte du nouveau type d'incertitude induit par l'utilisation d'un métamodèle. Cette prise en compte est nécessaire pour une estimation correcte de la précision de la calibration. La nouvelle méthode de calibration Bayésienne a été testée sur le cas applicatif ferroviaire, et a produit des résultats concluants. La validation a été faite par expériences numériques. Par ailleurs, l'évolution à long terme des paramètres mécaniques de suspensions a été étudiée à partir de mesures réelles de la réponse dynamique du train
The work presented here deals with the development of a health-state monitoring method for high-speed train suspensions using in-service measurements of the train dynamical response by embedded acceleration sensors. A rolling train is a dynamical system excited by the track-geometry irregularities. The suspension elements play a key role for the ride safety and comfort. The train dynamical response being dependent on the suspensions mechanical characteristics, information about the suspensions state can be inferred from acceleration measurements in the train by embedded sensors. This information about the actual suspensions state would allow for providing a more efficient train maintenance. Mathematically, the proposed monitoring solution consists in solving a statistical inverse problem. It is based on a train-dynamics computational model, and takes into account the model uncertainty and the measurement errors. A Bayesian calibration approach is adopted to identify the probability distribution of the mechanical parameters of the suspension elements from joint measurements of the system input (the track-geometry irregularities) and output (the train dynamical response).Classical Bayesian calibration implies the computation of the likelihood function using the stochastic model of the system output and experimental data. To cope with the fact that each run of the computational model is numerically expensive, and because of the functional nature of the system input and output, a novel Bayesian calibration method using a Gaussian-process surrogate model of the likelihood function is proposed. This thesis presents how such a random surrogate model can be used to estimate the probability distribution of the model parameters. The proposed method allows for taking into account the new type of uncertainty induced by the use of a surrogate model, which is necessary to correctly assess the calibration accuracy. The novel Bayesian calibration method has been tested on the railway application and has achieved conclusive results. Numerical experiments were used for validation. The long-term evolution of the suspension mechanical parameters has been studied using actual measurements of the train dynamical response

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Casadei, Francesco. "Experimental investigation of the flow behind a probe rake: a similarity analysis for high speed applications." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4887/.

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Haag, Maria. "Problems concerning pantograph collection of current during winter for high speed trains." Thesis, KTH, Maskinkonstruktion (Inst.), 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-99339.

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The idea of making this report was to try and shed light on the many problems of pantograph collection of current during winter time for high speed trains. The greatest difference between Sweden and other countries who already have built high speed rails is our yearly severe winter conditions. The problem about pantograph collection during winter is that the contact between the pantograph and the contact wire gets worse if ice isolates in between those two. That creates electric arcs that can harm both the pantograph and the overhead contact wire. For a high speed track the problems are expected to be even greater. It’s important that the Swedish Transport Administration, at an early stage, learns what causes the delays and the unwanted stops. My work started by doing a thorough literature study, where I tried to summon the overhead contact line theory from a winter perspective. After this a number of attempts have been made to illustrate different solutions on how to avoid that ice stays on the overhead contact line or the pantograph. In the first attempt I examined the thickness the ice would get on the contact wire if the air temperature suddenly fell from 0 C till  5 C and super cooled rain would fall for an entire 24-hour period. In my second attempt I tried the possibility to use a heated pantograph combined with an ice scraper. I used an American ice scraper as basic idea, but modified the contact strip part and made its shape cylindrical and hollow. The idea was that the scraper would reduce the ice on the wire and that the heated brass contact strip would melt the rest. In attempt three I looked into other materials that would be more suited for winter climate. As suspected the already existing materials, are not good enough and the futuristic ones are too expensive at the present time. Attempt number four was all about heating the contact wire with a magnetron that was going to be assembled on the pantograph. Unfortunately this result was not a success as it turned out that ice does not heat very well from microwaves. In the fifth attempt I focused on ice scrapers by studying tribology. Using an ice scraper may work, but probably best in combination with some of the other methods. Testing how this would be done in the best way will take some time. In the sixth attempt I looked into the possibility of heating the contact wire by adding extra current to the system. This is the way of handling the problem that I believe to be the most promising. In addition to these approaches, a simulation was made to show a phase change in the computer program Comsol.
Syftet med examensarbetet är att belysa problematiken kring strömavtagning vintertid för hög-hastighetståg. De största skillnaderna mellan Sverige och många andra länder som redan byggt höghastighetsbanor är, att vi årligen drabbas av kraftig vinter och de länder som har vinter oftast har annan kraftförsörjning. Problemet med strömavtagning vintertid är att kontakten mellan strömavtagare och kontaktledning försämras om det ligger is emellan. Då skapas överslag i form av ljusbågar som då sliter hårt på både strömavtagare och kontaktledning. För en höghastig-hetsbana förväntas problemen öka ytterligare. En stor del av poängen med att bygga en sådan är att vinna tid, så om banan drabbas av frekventa störningar under vinterhalvåret är vitsen borta. Det är viktigt att Trafikverket redan i ett tidigt skede får klart för sig orsaken. Arbetet började med en grundlig litteraturstudie där jag försökte sammanställa kontaktlednings-teorin med utgångspunkten vinter med fokus på åtgärder. Jag använde därefter sex olika ansatser, på olika sätt att förhindra isbildning på kontakttråd och slitskena. I den första undersökningen tog jag reda på vilken istjocklek det skulle bli på kontaktledningen om lufttemperaturen sjönk momentant från till och det kontinuerligt skulle regna underkylt under 1 dygn. C 0 C  5 I den andra undersökningen utredde jag möjligheten att använda en varm strömavtagare kombin-erad med isskrapa. Jag använde en amerikansk grundidé men modifierade mässingslitdelen samt gjorde den cylindrisk och ihålig. Tanken var sedan att skrapan skulle reducera isen till max 3 mm på tråden och att det uppvärmda mässingsröret skulle klara att smälta resten. I undersökning tre tittade jag på möjligheten att välja bättre material ur vintersynpunkt. Som jag misstänkte har de alternativa, redan befintliga materialen idag stora nackdelar och de framtida en tid kvar innan de blir prisvärda. Fjärde undersökningen gick ut på att värma kontakttråden med en magnetron monterad på slitskenan. Detta försök var inte helt lyckat, eftersom is inte värms speciellt bra av mikrovågor. I undersökning fem fokuserade jag på isskrapor och för detta krävdes en fördjupning inom ämnet tribologi. En isskrapa skulle kunna användas, men då troligen i kombination till någon av de övriga metoderna. Att testa ut hur detta skulle göras på bästa sätt kommer att ta lång tid. Den sjätte ansatsen behandlade uppvärmning av kontaktledningen med hjälp av krypström. Denna lösning är nog den jag personligen tror mest på. Dessutom modellerade jag en fasomvandling och förutspådde dess påverkan på värmeöver-föringsförmågan genom att göra en simulering i dataprogrammet Comsol.

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Tong, Tsz Kin Jimmy. "A finite element approach to the planing problem of high speed craft." Thesis, University of Southampton, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.278920.

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Raavi, Venkata Suresh. "A Novel Approach to Dilemma Zone Problem for High Speed Signalized Intersections." University of Akron / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=akron1268252216.

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Pantaloni, Luigi. "Experimental analysis of the flow behind a probe rake in a high speed subsonic wind tunnel." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2013. http://amslaurea.unibo.it/4882/.

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Doležal, Pavel. "Rozšíření aplikace DPDK DNS Probe." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2019. http://www.nusl.cz/ntk/nusl-399183.

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This master's thesis is focused on extension of the DPDK DNS Probe application that monitors DNS traffic in high speed networks. It presents framework DPDK, which can be used for fast packet processing. General architecture of the DNS system is described as well as details of its components. Basic principles of transport protocol TCP are described. It introduces an effective design and implementation of DNS packet parsing to optimize DPDK DNS Probe's performance. It also introduces a design and implementation of processing DNS messages sent over TCP for export of traffic statistics. The application's performance was tested using a high speed traffic generator Spirent.

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Duan, G. (Guoyong). "Three-dimensional effects and surface breakdown addressing efficiency and reliability problems in avalanche bipolar junction transistors." Doctoral thesis, Oulun yliopisto, 2013. http://urn.fi/urn:isbn:9789526200859.

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Abstract Although avalanche switching has been known since the 1950s, a trustworthy one-dimensional physical interpretation of the practically interesting high-current mode ("secondary breakdown") in a Si avalanche transistor has appeared only within the last decade and thanks to numerical one-dimensional and two-dimensional physics-based device modelling. A good fit with experimental waveforms has been achieved only for high-current, long-duration pulses (~100 A/7 ns), however, and modelling fails in the case of shorter pulses in a range that is of greater practical importance. One significant finding in this thesis is that reliable modelling of a Si avalanche transistor is in general impossible without taking account of three-dimensional effects. The task is a challenging one, as it is being put forward for the first time and state-of-the-art simulators are unable to model three-dimensional avalanche dynamics with an external circuit included (i.e. in “MixedMode”). Thus a smart approach was adopted which allowed the main features of the three-dimensional transient to be explained using a two-dimensional simulator and compared with the experimental data. The focus was on a trade-off of between high switching efficiency in an avalanche transistor (high-speed switching with a lower residual voltage as occurs at extremely high current densities) and device reliability as determined by local overheating during a single pulse, similarly resulting from high current density. This denotes the practical importance of the work performed here, as the current density is directly affected by three-dimensional dynamic processes. The second task performed in this thesis concerns the reliability of the GaAs avalanche transistors developed recently in the Electronics Laboratory and demonstrated of unique (superfast) switching and high-power-density sub-THz emission for mm-wave imaging and radars. Critically important for this new device is the limitation originating from premature breakdown at the surface of the GaAs p-n junction with a high density of surface states. Two of the results of this work are also fairly challenging: (i) the mechanism of "soft" surface breakdown intrinsic to all GaAs transistor mesas was interpreted in terms of the surface trapping of avalanche-generated electrons as suggested here, and (ii) passivation of the surface with a chalcogenide glass was suggested, as this allows the premature surface breakdown to be suppressed completely, an effect that has proved to be caused by a large negative surface charge formed on the “U centres” intrinsic to a chalcogenide glass
Tiivistelmä Vaikka avalanche läpilyönti pii-transistoreissa on tunnettu jo 1950-luvulta lähtien, luotettava 1-dimensionaalinen fysikaalinen tulkinta ilmiöstä käytännön sovellusten kannalta kiinnostavilla suurilla virtatasoilla (ns. “secondary breakdown”) on esitetty vasta viime vuosikymmenen aikana 1- ja 2-dimensionaalisiin numeerisiin simulointeihin ja fysikaaliseen mallinnukseen perustuen. Kokeellisten mittausten ja simulointien välille on saatu hyvä sovitus kuitenkin vain sellaisessa ohjaustilanteessa, jossa transistori toimii suurella virtatasolla ja tuottaa leveitä virtapulsseja (~100 A / 7 ns); mallinnus ei vastaa mittaustuloksia lyhyillä virtapulsseilla, jotka kuitenkin ovat tärkeitä käytännön sovellusten kannalta. Yksi tämän työn keskeisiä havaintoja on se, että piipohjaisen avalanche transistorin luotettava mallintaminen ei ole käytännössä yleisesti mahdollista ottamatta huomioon 3-dimensionaalisia (3D) efektejä. Tällainen mallinnus, jota tässä työssä on kehitetty ensimmäistä kertaa, on vaikeaa, koska kaupalliset simulointiohjelmistot eivät kykene käsittelemään avalanche ilmiön dynamiikka 3-dimensionaalisesti tilanteessa, jossa transistoriin on kytketty ulkoinen piiri (ns. mixed-mode -simulointitilanne). Tähän kehitettiin tekniikka, joka mahdollistaa 3-dimensionaalisen kytkentätransientin tärkeimpien piirteiden selittämisen ja mittaustuloksiin vertaamisen 2-dimensionaalisten simulointien perusteella. Erityisesti pyrittiin selvittämään avalanche transistorin korkean kytkentähyötysuhteen (kollektori-emitterin ns. residual-jännitteen käyttäytyminen virrantiheystason mukaan) ja komponentin luotettavuuden välistä riippuvuutta. Luotettavuuteen vaikuttaa olennaisesti komponentin sisäinen, lokalisoitunut lämpötilamaksimi, joka myös riippuu keskeisesti komponentin virrantiheystasosta kytkentäpulssin aikana. Toisaalta virrantiheyteen vaikuttavat juuri komponentin 3-dimensionaaliset dynaamiset prosessit, joten työn käytännöllinen merkitys on suuri. Työn toisen osa käsittelee elektroniikan laboratoriossa äskettäin kehitetyn GaAs-avalanche transistorin luotettavuutta. Tällaisella transistorilla on demonstroitu olevan erityislaatuinen supernopea kytkeytymisefekti, ja se emittoi korkealla tehotasolla sähkömagneettista säteilyä n. 0,1–1 THz taajuusalueella. GaAs-avalanche transistoria voidaan täten potentiaalisesti hyödyntää mm-alueen kuvantamisessa ja tutkissa. Tämän uuden transistorin luotettavuuteen vaikuttaa ratkaisevasti rajoitus, joka aiheutuu ennenaikaisen, GaAs-pn-liitoksen pinnassa vaikuttavasta suuresta pintatilatiheydestä johtuvan läpilyönnin mahdollisuudesta. Työn kaksi keskeistä tulosta ovat: (i) kaikilla GaAs-transistoreilla ilmenevä ns. ”pehmeä”-läpilyönti aiheutuu avalanche ilmiön synnyttämien elektronien loukkuuntumisesta pinta-tiloihin, ja (ii) pinnan passivointi kalkopyriittilasilla estää läpilyönnin kokonaan, koska kalkopyriittilasille luonteenomaiset ”U-tilat” aiheuttavat liitoksen pintaan korkean negatiivisen pintavarauksen

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Lestoille, Nicolas. "Stochastic model of high-speed train dynamics for the prediction of long-time evolution of the track irregularities." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1094/document.

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Les voies ferrées sont de plus en plus sollicitées: le nombre de trains à grande vitesse, leur vitesse et leur charge ne cessent d'augmenter, ce qui contribue à la formation de défauts de géométrie sur la voie. En retour, ces défauts de géométrie influencent la réponse dynamique du train et dégradent les conditions de confort. Pour garantir de bonnes conditions de confort, les entreprises ferroviaires réalisent des opérations de maintenance de la voie, qui sont très coûteuses. Ces entreprises ont donc intérêt à prévoir l'évolution temporelle des défauts de géométrie de la voie pour anticiper les opérations de maintenance, et ainsi réduire les coûts de maintenance et améliorer les conditions de transport. Dans cette thèse, on analyse l'évolution temporelle d'une portion de voie par un indicateur vectoriel sur la dynamique du train. Pour la portion de voie choisie, on construit un modèle stochastique local des défauts de géométrie de la voie à partir d'un modèle global des défauts de géométrie et de big data de défauts mesurés par un train de mesure. Ce modèle stochastique local prend en compte la variabilité des défauts de géométrie de la voie et permet de générer des réalisations des défauts pour chaque temps de mesure. Après avoir validé le modèle numérique de la dynamique du train, les réponses dynamiques du train sur la portion de voie mesurée sont simulées numériquement en utilisant le modèle stochastique local des défauts de géométrie. Un indicateur dynamique, vectoriel et aléatoire, est introduit pour caractériser la réponse dynamique du train sur la portion de voie. Cet indicateur dynamique est construit de manière à prendre en compte les incertitudes de modèle dans le modèle numérique de la dynamique du train. Pour identifier le modèle stochastique des défauts de géométrie et pour caractériser les incertitudes de modèle, des méthodes stochastiques avancées, comme par exemple la décomposition en chaos polynomial ou le maximum de vraisemblance multidimensionnel, sont appliquées à des champs aléatoires non gaussiens et non stationnaires. Enfin, un modèle stochastique de prédiction est proposé pour prédire les quantités statistiques de l'indicateur dynamique, ce qui permet d'anticiper le besoin en maintenance. Ce modèle est construit en utilisant les résultats de la simulation de la dynamique du train et consiste à utiliser un modèle non stationnaire de type filtre de Kalman avec une condition initiale non gaussienne
Railways tracks are subjected to more and more constraints, because the number of high-speed trains using the high-speed lines, the trains speed, and the trains load keep increasing. These solicitations contribute to produce track irregularities. In return, track irregularities influence the train dynamic responses, inducing degradation of the comfort. To guarantee good conditions of comfort in the train, railways companies perform maintenance operations of the track, which are very costly. Consequently, there is a great interest for the railways companies to predict the long-time evolution of the track irregularities for a given track portion, in order to be able to anticipate the start off of the maintenance operations, and therefore to reduce the maintenance costs and to improve the running conditions. In this thesis, the long-time evolution of a given track portion is analyzed through a vector-valued indicator on the train dynamics. For this given track portion, a local stochastic model of the track irregularities is constructed using a global stochastic model of the track irregularities and using big data made up of experimental measurements of the track irregularities performed by a measuring train. This local stochastic model takes into account the variability of the track irregularities and allows for generating realizations of the track irregularities at each long time. After validating the computational model of the train dynamics, the train dynamic responses on the measured track portion are numerically simulated using the local stochastic model of the track irregularities. A vector-valued random dynamic indicator is defined to characterize the train dynamic responses on the given track portion. This dynamic indicator is constructed such that it takes into account the model uncertainties in the train dynamics computational model. For the identification of the track irregularities stochastic model and the characterization of the model uncertainties, advanced stochastic methods such as the polynomial chaos expansion and the multivariate maximum likelihood are applied to non-Gaussian and non-stationary random fields. Finally, a stochastic predictive model is proposed for predicting the statistical quantities of the random dynamic indicator, which allows for anticipating the need for track maintenance. This modeling is constructed using the results of the train dynamics simulation and consists in using a non-stationary Kalman-filter type model with a non-Gaussian initial condition. The proposed model is validated using experimental data for the French railways network for the high-speed trains

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Pasciak, Alexander Samuel. "The development of a high speed solution for the evaluation of track structure Monte Carlo electron transport problems using field programmable gate arrays." [College Station, Tex. : Texas A&M University, 2007. http://hdl.handle.net/1969.1/ETD-TAMU-2558.

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Perrin, Guillaume. "Random fields and associated statistical inverse problems for uncertainty quantification : application to railway track geometries for high-speed trains dynamical responses and risk assessment." Phd thesis, Université Paris-Est, 2013. http://pastel.archives-ouvertes.fr/pastel-01001045.

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Les nouvelles attentes vis-à-vis des nouveaux trains à grande vitesse sont nombreuses: on les voudrait plus rapides, plus confortables, plus stables, tout en étant moins consommateur d'énergie, moins agressif vis-à-vis des voies, moins bruyants... Afin d'optimiser la conception de ces trains du futur, il est alors nécessaire de pouvoir se baser sur une connaissance précise de l'ensemble des conditions de circulations qu'ils sont susceptibles de rencontrer au cours de leur cycle de vie. Afin de relever ces défis, la simulation a un très grand rôle à jouer. Pour que la simulation puisse être utilisée dans des perspectives de conception, de certification et d'optimisation de la maintenance, elle doit alors être tout à fait représentative de l'ensemble des comportements physiques mis en jeu. Le modèle du train, du contact entre les roues et le rail, doivent ainsi être validés avec attention, et les simulations doivent être lancées sur des ensembles d'excitations qui sont réalistes et représentatifs de ces défauts de géométrie. En ce qui concerne la dynamique, la géométrie de la voie, et plus particulièrement les défauts de géométrie, représentent une des principales sources d'excitation du train, qui est un système mécanique fortement non linéaire. A partir de mesures de la géométrie d'un réseau ferroviaire, un paramétrage complet de la géométrie de la voie et de sa variabilité semblent alors nécessaires, afin d'analyser au mieux le lien entre la réponse dynamique du train et les propriétés physiques et statistiques de la géométrie de la voie. Dans ce contexte, une approche pertinente pour modéliser cette géométrie de la voie, est de la considérer comme un champ aléatoire multivarié, dont les propriétés sont a priori inconnues. En raison des interactions spécifiques entre le train et la voie, il s'avère que ce champ aléatoire n'est ni Gaussien ni stationnaire. Ce travail de thèse s'est alors particulièrement concentré sur le développement de méthodes numériques permettant l'identification en inverse, à partir de mesures expérimentales, de champs aléatoires non Gaussiens et non stationnaires. Le comportement du train étant très non linéaire, ainsi que très sensible vis-à-vis de la géométrie de la voie, la caractérisation du champ aléatoire correspondant aux défauts de géométrie doit être extrêmement fine, tant du point de vue fréquentiel que statistique. La dimension des espaces statistiques considérés est alors très importante. De ce fait, une attention toute particulière a été portée dans ces travaux aux méthodes de réduction statistique, ainsi qu'aux méthodes pouvant être généralisées à la très grande dimension. Une fois la variabilité de la géométrie de la voie caractérisée à partir de données expérimentales, elle doit ensuite être propagée au sein du modèle numérique ferroviaire. A cette fin, les propriétés mécaniques d'un modèle numérique de train à grande vitesse ont été identifiées à partir de mesures expérimentales. La réponse dynamique stochastique de ce train, soumis à un très grand nombre de conditions de circulation réalistes et représentatives générées à partir du modèle stochastique de la voie ferrée, a été ainsi évaluée. Enfin, afin d'illustrer les possibilités apportées par un tel couplage entre la variabilité de la géométrie de la voie et la réponse dynamique du train, ce travail de thèse aborde trois applications

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17

Villafañe, Roca Laura. "Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers." Doctoral thesis, Universitat Politècnica de València, 2014. http://hdl.handle.net/10251/34774.

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The path to future aero-engines with more efficient engine architectures requires advanced thermal management technologies to handle the demand of refrigeration and lubrication. Oil systems, holding a double function as lubricant and coolant circuits, require supplemental cooling sources to the conventional fuel based cooling systems as the current oil thermal capacity becomes saturated with future engine developments. The present research focuses on air/oil coolers, which geometrical characteristics and location are designed to minimize aerodynamic effects while maximizing the thermal exchange. The heat exchangers composed of parallel fins are integrated at the inner wall of the secondary duct of a turbofan. The analysis of the interaction between the three-dimensional high velocity bypass flow and the heat exchangers is essential to evaluate and optimize the aero-thermodynamic performances, and to provide data for engine modeling. The objectives of this research are the development of engine testing methods alternative to flight testing, and the characterization of the aerothermal behavior of different finned heat exchanger configurations. A new blow-down wind tunnel test facility was specifically designed to replicate the engine bypass flow in the region of the splitter. The annular sector type test section consists on a complex 3D geometry, as a result of three dimensional numerical flow simulations. The flow evolves over the splitter duplicated at real scale, guided by helicoidally shaped lateral walls. The development of measurement techniques for the present application involved the design of instrumentation, testing procedures and data reduction methods. Detailed studies were focused on multi-hole and fine wire thermocouple probes. Two types of test campaigns were performed dedicated to: flow measurements along the test section for different test configurations, i.e. in the absence of heat exchangers and in the presence of different heat exchanger geometries, and heat transfer measurements on the heat exchanger. As a result contours of flow velocity, angular distributions, total and static pressures, temperatures and turbulence intensities, at different bypass duct axial positions, as well as wall pressures along the test section, were obtained. The analysis of the flow development along the test section allowed the understanding of the different flow behaviors for each test configuration. Comparison of flow variables at each measurement plane permitted quantifying and contrasting the different flow disturbances. Detailed analyses of the flow downstream of the heat exchangers were assessed to characterize the flow in the fins¿ wake region. The aerodynamic performance of each heat exchanger configuration was evaluated in terms of non dimensional pressure losses. Fins convective heat transfer characteristics were derived from the infrared fin surface temperature measurements through a new methodology based on inverse heat transfer methods coupled with conductive heat flux models. The experimental characterization permitted to evaluate the cooling capacity of the investigated type of heat exchangers for the design operational conditions. Finally, the thermal efficiency of the heat exchanger at different points of the flight envelope during a typical commercial mission was estimated by extrapolating the convective properties of the flow to flight conditions.
Villafañe Roca, L. (2013). Experimental Aerothermal Performance of Turbofan Bypass Flow Heat Exchangers [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/34774
TESIS

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O'Dowd, Devin Owen. "Aero-thermal performance of transonic high-pressure turbine blade tips." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:e7b8e7d0-4973-4757-b4df-415723e7562f.

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Durán, Alcaide Ángel. "Development of high-performance algorithms for a new generation of versatile molecular descriptors. The Pentacle software." Doctoral thesis, Universitat Pompeu Fabra, 2010. http://hdl.handle.net/10803/7201.

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The work of this thesis was focused on the development of high-performance algorithms for a new generation of molecular descriptors, with many advantages with respect to its predecessors, suitable for diverse applications in the field of drug design, as well as its implementation in commercial grade scientific software (Pentacle). As a first step, we developed a new algorithm (AMANDA) for discretizing molecular interaction fields which allows extracting from them the most interesting regions in an efficient way. This algorithm was incorporated into a new generation of alignmentindependent molecular descriptors, named GRIND-2. The computing speed and efficiency of the new algorithm allow the application of these descriptors in virtual screening. In addition, we developed a new alignment-independent encoding algorithm (CLACC) producing quantitative structure-activity relationship models which have better predictive ability and are easier to interpret than those obtained with other methods.
El trabajo que se presenta en esta tesis se ha centrado en el desarrollo de algoritmos de altas prestaciones para la obtención de una nueva generación de descriptores moleculares, con numerosas ventajas con respecto a sus predecesores, adecuados para diversas aplicaciones en el área del diseño de fármacos, y en su implementación en un programa científico de calidad comercial (Pentacle). Inicialmente se desarrolló un nuevo algoritmo de discretización de campos de interacción molecular (AMANDA) que permite extraer eficientemente las regiones de máximo interés. Este algoritmo fue incorporado en una nueva generación de descriptores moleculares independientes del alineamiento, denominados GRIND-2. La rapidez y eficiencia del nuevo algoritmo permitieron aplicar estos descriptores en cribados virtuales. Por último, se puso a punto un nuevo algoritmo de codificación independiente de alineamiento (CLACC) que permite obtener modelos cuantitativos de relación estructura-actividad con mejor capacidad predictiva y mucho más fáciles de interpretar que los obtenidos con otros métodos.

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Lee, Yi-Chang, and 李宜璋. "The Study of MEMS Probes for High-Speed, High-Frequency, and High-Parallel Wafer-Level Testing." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/16473957322483328268.

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碩士
國立成功大學
微電子工程研究所碩博士班
92
The current trend is towards device miniaturization. In other words, there will be placed more devices in the same area. Besides, the current trend is towards high frequency. In the process of wafer-level testing, we can find the tarnish from these small and quick devices to ensure the yield of the products and then save cost. This is why the probe card manufacturers are willing to study or act for the high-speed, high-frequency, and high-parallel probe card. 　　In this paper, we realize the probe card and probe approximately. In the process of study and fabrication, we decide the scale of the structure for HFSS in the first place. Second, we realize the initial procedure of the probe fabrication by the material characteristics and mechanical properties, and study the feasibility of probe fabrication by the cooperation and comparison of the simulation parameters and fabrication techniques.

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Sri, Ram Shankar R. "A Probing System for Dynamic Mode Atomic Force Microscopy Based on Specialized Probes." Thesis, 2017. http://etd.iisc.ac.in/handle/2005/4292.

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The dynamic mode atomic force microscope (AFM) is a versatile tool that uses a resonantly excited micro-cantilever probe to obtain a sample’s topography and to characterize its material properties. While a number of useful techniques have been developed for interacting with the sample, conventional AFM probes and AFM systems do not facilitate their effective implementation. This thesis investigates the design of specialized AFM probes and the development of a novel probing system that improves the speed of imaging and enhances the sensitivity to material properties in dynamic mode AFM. In order to perform high speed imaging, an integrated high-bandwidth magnetic actuation system, comprising a special probe and an actuator, is designed and developed. Subsequently, the actuation system is fabricated and evaluated using an in-house developed measurement system to possess an eigen-frequency of 104 kHz and a range of 225 nm. In aqueous medium, the probe is shown to suffer 3 times lesser reduction in eigen-frequency compared to a conventional probe of similar eigen-frequency in air. In order to achieve enhanced sensitivity to material properties, a systematic approach is proposed to design and fabricate probes with specified eigen-frequencies. The proposed approach is employed to design and develop a flexural harmonic probe with eigen-frequencies in the ratio 1:2 and a torsional harmonic probe with eigen-frequencies in the ratio 1:2:3. The experimentally evaluated eigen-frequency ratios are shown to match the specifications to within 0.4% and 2% respectively. Further, harmonic probes with exchangeable tips are proposed and a prototype probe is fabricated and evaluated. The developed harmonic probes are shown to be significantly more sensitive to tip-sample forces. To effectively exploit the high speed and sensitivity of the developed probes, a custom AFM system is designed and developed in-house. The AFM includes a novel Z-magnetic actuation system having bandwidth in excess of 3 MHz and an XY nano-positioning system suitable for video-rate imaging. A novel measurement system based on optical beam deflection is developed and evaluated to measure XY-motion of the positioner. High speed control hardware based on Field Programmable Gate Array (FPGA) has been used for data acquisition and real-time control, with update rates of more than 5 MHz. The developed system is demonstrated to enhance the positioning bandwidth of the high-speed AFM probe, and subsequently employed in high-speed dynamic mode AFM imaging at rates upto 1.25 frames/second. Finally, the potential of the developed system for video-rate dynamic mode AFM imaging, and in-situ material characterization is discussed.

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Hung, Mei-Xin, and 黃眉欣. "High Speed Grinding Small Angle Micro Probe." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/976kf7.

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碩士
國立虎尾科技大學
機械與機電工程研究所
98
In response to the characteristics of different probe material, this experiment used a processing method which was not affected by any material properties, to make the probe achieve micron level and facilitate more accurate measurement. This paper used multiple pneumatic grinding spindles to combine with micro cutting-edge technology, and applied to palladium alloy, pure tungsten, and zirconium oxide. By this system, with the experiment which chose the 25μm and 5μm granularity of diamond grinding wheels, with 32,000rpm, 50,000rpm, and 53,000rpm of rotation speeds, and the 13°and 10°of the offset grinding angle between grinding wheel and bar to grind out three grinding parameters of micro sophisticated probes, which were granularity, rotation speed, and the offset grinding angle of grinding wheel and bar, respectively. By this system, it could also grind out various shapes probes, such as cone, cylinder and disc. From the experimental results, it could be known that the big angle of grinding, high rotation speed, and small granularity could grind out better micro sophisticated probes; and by adding the cutting agent during the grinding process could reduce the chip interference and increase the success rate of grinding out micro sophisticated probes. Therefore, the experiment could grinding out the 0.62μm of cone-shaped probe by using the 5μm granularity of diamond grinding wheel, with 50,000rpm of rotational speed and 13°of grinding angle; it could also make 66.0μm diameter of cylinder and 56.0μm thickness of the disc-shaped.

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Wu, Shin-Kuan, and 吳信寬. "High speed trace design for probe head applications." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/95923211314137973615.

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碩士
國立成功大學
微電子工程研究所碩博士班
91
In order to manufacture traces on the probe head, we compared the three kinds of traces, microstrip line, embedded line and symmetry stripline to find the minimum trace standards on polyimide and Silicon substrate. In this way, we know the width of embedded line can be decrease to 12μm. If line space is 30μm as for the probe substrate in 50mm×50mm, each side can have 1190 probe circuit pads. For the parallel traces, we can use U-type traces to decrease the crosstalk. Using microstrip lines and embedded lines in double-deck structure can increase more traces. In this experiment, we use polyimide to complete the probe head. In the future, we can also use other dielectric materials to achieve the goal.

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24

Κωτσόπουλος, Ανδρέας. "Σπειροειδής κίνηση και έλεγχος σε μικρο/νανο-ηλεκτρομηχανικά συστήματα αποθήκευσης πληροφορίας." Thesis, 2012. http://hdl.handle.net/10889/5956.

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Οι τεχνικές Μικροσκοπίας Ατομικής Δύναμης που χρησιμοποιούν ακίδες σάρωσης έχουν την ικανότητα όχι μόνο να παρατηρούν επιφάνειες σε ατομικό επίπεδο αλλά και να τις τροποποιούν σε πολύ μικρή κλίμακα. Αυτό αποτελεί και το κίνητρο για τη χρησιμοποίηση των τεχνικών αυτών στη δημιουργία συσκευών αποθήκευσης με πολύ μεγαλύτερη πυκνότητα από τις συμβατικές συσκευές. Σε διάφορα ερευνητικά προγράμματα αποθήκευσης δεδομένων τεχνολογίας MEMS/NEMS με ακίδες, η σχετική τροχιά κίνησης της ακίδας ως προς το αποθηκευτικό μέσο ακολουθεί ένα μοτίβο raster. Παρά την απλή υλοποίησή της, η προαναφερθείσα κίνηση σάρωσης έχει σημαντικά μειονεκτήματα. Στο πλαίσιο της εργασίας αυτής προτείνεται μια εναλλακτική τοπολογία σπειροειδούς κίνησης. Η προτεινόμενη μέθοδος μπορεί να εφαρμοσθεί σε οποιοδήποτε σύστημα που βασίζεται σε διαδικασίες σάρωσης, όπως συστήματα αποθήκευσης και AFM συστήματα απεικόνισης. Στην εργασία αυτή μελετάται η περίπτωση των συσκευών αποθήκευσης με ακίδες, όπου η τροχιά που διαγράφει η ακίδα σε σχέση με το επίπεδο x/y που ορίζεται από το μέσο αποθήκευσης, είναι η σπειροειδής καμπύλη του Αρχιμήδη. Η χρήση μιας τέτοιας σπειροειδούς τροχιάς οδηγεί σε σήμα θέσης αναφοράς με εξαιρετικά στενό συχνοτικό περιεχόμενο, το οποίο ολισθαίνει πολύ αργά στον χρόνο. Για πειραματική επιβεβαίωση, ο προτεινόμενος τρόπος σπειροειδούς κίνησης εφαρμόστηκε σε σύστημα αποθήκευσης πληροφορίας με ακίδες με δυνατότητες θερμομηχανικής εγγραφής και ανάγνωσης δεδομένων σε φιλμ πολυμερούς. Επιπλέον, μελετήθηκε η αξιοποίηση των ιδιοτήτων του νέου τύπου κίνησης από αρχιτεκτονικές ελέγχου ειδικά σχεδιασμένες και βελτιστοποιημένες για τη συγκεκριμένη οικογένεια τροχιών αναφοράς, με στόχο την επίτευξη πολύ υψηλότερων συχνοτήτων σάρωσης για την ίδια ακρίβεια θέσης. Προς επιβεβαίωση των θεωρητικών αναλύσεων, παρουσιάζονται αποτελέσματα εξομοιώσεων καθώς και πειραματικά αποτελέσματα από πειραματική διάταξη. Στο πλαίσιο της διατριβής πραγματοποιήθηκε και η μοντελοποίηση του καναλιού θερμομηχανικής αποθήκευσης με ακίδες σε μεμβράνες πολυμερούς υλικού. Ενώ η θεωρητική μορφή των θερμομηχανικά εγγεγραμμένων κοιλωμάτων είναι κωνική, στην πράξη η μορφή του απέχει πολύ από το θεωρητικό μοντέλο. Για τον λόγο αυτό, αναπτύχθηκε μοντέλο του συμβόλου ως προς την ταχύτητα σάρωσης κατά τη διαδικασία εγγραφής, με βάση πειραματικά δεδομένα. Στο πλαίσιο της διατριβής μελετήθηκε επίσης η δυνατότητα ανάπτυξης συνδυασμένων αρχιτεκτονικών ελέγχου παρακολούθησης και ανάκτησης χρονισμού συμβόλου, όπου η πληροφορία για τη στιγμιαία ταχύτητα του σαρωτή παρέχεται από το μέσο αποθήκευσης μέσω των κυκλωμάτων συγχρονισμού. Τα αποτελέσματα των εξομοιώσεων επιβεβαιώνουν την δυνατότητα αυτή, και επιπλέον δείχνουν ότι υπό προϋποθέσεις η ακρίβεια παρακολούθησης του συστήματος βελτιώνεται. Τέλος, διερευνήθηκε η απόδοση των προτεινόμενων μεθόδων στην περίπτωση φορητών συσκευών, τα οποία υπόκεινται σε εξωτερικές διαταραχές. Στο πλαίσιο της διερεύνησης αυτής, συλλέχθηκαν πειραματικά αποτελέσματα και αναλύθηκαν μετρήσεις τυπικών εξωτερικών διαταραχών.
The AFM techniques using scanning probes have the capacity not only to observe surfaces in atomic level but also to modify them at a very small scale. This feature motivates the use of these techniques to create storage devices capable of storing data in a much higher density than conventional devices. In various MEMS/NEMS-based data storage technology research projects with probes, the relative trajectory follows a raster pattern or similar. Despite its simple implementation, the aforementioned scanning pattern has significant disadvantages. In this work, an alternative spiral motion topology is proposed. The proposed method can be applied to any system based on scanning probes, such as storage systems and AFM imaging systems. In this work, the case of storage devices with probes is studied, in which the trajectory of the probe with respect to the x/y plane of the storage medium, is the spiral curve of Archimedes. The use of such a spiral trajectory leads to a reference position signal with extremely narrowband frequency content, which slides very slowly in time. For experimental verification, the proposed method of spiral motion was applied on a single probe experimental setup, with read and writes data thermomechanical capabilities on very thin polymer films. The aforementioned inherent properties of the proposed approach enable system designs with improved tracking performance and with non-intermittent, high-speed storage capabilities. Thus, the exploitation of these properties by architectures specifically designed and optimized for the particular reference trajectory is studied, in order to achieve much higher scanning frequencies for the same positioning accuracy. To verify the theoretical analysis, simulation results are presented as well as experimental results from the application of the proposed techniques and architectures in experimental AFM systems with a single probe. In this dissertation the modeling of the thermomechanical storage channel with probes in thin polymer films was also carried out. While the theoretical form of thermomechanically engraved indentations is conical, in practice its form is far from this theoretical model. Hence, a symbol model was developed in respect to the scanning speed during the write process, based on experimental data. This model can be used to properly design the equalization circuits depending on the motion speed of operation. Moreover, the possibility of developing combined architectures of tracking control and symbol timing recovery was also investigated, where the information regarding the scanner speed is provided from the storage medium via symbol timing synchronization circuits. The simulation results confirm this approach and, furthermore, show that, under certain conditions, the system’s tracking accuracy is improved. Finally, the performance of the proposed methods in the case of portable storage devices was investigated, where the systems are subjected to external disturbances. As part of this investigation, experimental results were collected and measurements of external disturbances, typical for such devices, were analyzed.

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25

Schade, Dennis K. "High speed signal processing for an opto-electronic probe." 1986. http://catalog.hathitrust.org/api/volumes/oclc/14908375.html.

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Thesis (M.S.)--University of Wisconsin--Madison, 1986.
Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 163-164).

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26

Larson, David J. "Developments toward a high speed, high mass resolution three-dimensional atom probe." 1996. http://catalog.hathitrust.org/api/volumes/oclc/35731604.html.

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27

Shiung, Kuo-Fu, and 熊國甫. "Electrical Characterization of High-Parallel Probe Cards for High-Speed and High-Frequency Application." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/01007847535453120870.

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碩士
國立成功大學
微電子工程研究所碩博士班
92
Recently, the clock rate of 64MB DDR SDRAM has been reached to 200MHz. In this condition, the cost and time of testing might be increased. In order to overcome these problems, many Probe Card manufacturing companies follow the high-speed and high-frequency issues to design the better products, and increasing the number of high-parallel probe card. But many interferences such as reflection, cross-talk, and simultaneous switching noise (SSN), influence the Probe Card testing. 　　　The design of Interposer and Probe head on Probe Card, testing 32 die DDR SDRAM simultaneously are proposed in this dissertation. Design the specifications of transmission line and via by IE3D and Ansoft HFSS; then, by using Maxwell Q3D to do Signal Integrity, we can sure that the signal is correct on Interposer and Probe head. Finally, the testing of the “DDR SDRAM” can be cost down by our self-aligned technology.

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28

Lien, Chia-Hao, and 連家顥. "Development of an intellectualized symmetric high-speed dual-spindle grinding machine and study on LED tungsten carbide probe speedy grinding." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/5vkf97.

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29

Maroufi, Mohammad. "MEMS-based nanopositioning for on-chip high-speed scanning probe microscopy." Thesis, 2015. http://hdl.handle.net/1959.13/1309594.

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Research Doctorate - Doctor of Philosophy (PhD)
Nanopositioners constitute a crucial component of numerous emerging scientific instruments due to their ability to produce displacements with nanometer or sub-nanometer precision. In particular, these devices are predominantly used in scanning probe microscopes (SPMs) to position samples beneath the probe. The positioning precision of an incorporated nanopositioner directly affects the imaging quality of these microscopes. Since SPMs are mechanical microscopes, their imaging frame rate also depends on the speed of the implemented nanopositioner. In this research, the micro electromechanical system (MEMS) technology, as an alternative to macroscale technology, is used to realize high-speed on-chip nanopositioners for SPMs. Atomic force microscopes (AFMs), as an important subset of SPMs, are also used to test the capability of these nanopositioners in imaging. A comprehensive study is conducted on previously reported MEMS nanopositioners proposed for different applications. Various actuation and sensing techniques, which are viable to be incorporated in MEMS nanopositioners, are presented and their characteristics are thoroughly discussed. The design concerns relevant to electrostatic MEMS nanopositioners are discussed using analytical models. These models are later used as the baseline for designing novel electrostatic MEMS nanopositioners. These nanopositioners are fabricated and fully characterized as explained in different chapters in this thesis. All proposed nanopositioners are also used within an AFM for imaging. In addition, closed-loop feedback controllers are implemented for a number of the nanopositioners to attain raster and non-raster scans with a superior tracking performance. Both serial and parallel kinematic mechanisms are attempted for the implementation of the proposed nanopositioners. Various performance parameters relevant to the use of either of these mechanisms are investigated using experimental results. Displacement sensing bandwidth in some of the proposed nanopositioners is identified as a restricting factor to achieve higher scanning speeds. Hence, a novel high-bandwidth on-chip sensing mechanism for measuring stage displacement is introduced. The sensor is implemented in a single-degree-of-freedom MEMS nanopositioner as a test bench. Both analytical models and experimental data are provided for the sensor to investigate its static and dynamic features. To achieve a wider bandwidth, the on-chip configuration of the sensor is also modified, and the modified version is implemented in a novel two-degree-of-freedom MEMS nanopositioner. The performance results obtained from the proposed nanopositioners highlight their potential utility in a miniaturized high-speed AFM. The proposed nanopositioners demonstrate outstanding characteristics in terms of bandwidth, cross coupling rejection, and displacement range. All designs have the potential to be used in high accuracy positioning applications, particularly in on-chip AFMs.

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30

(10942896), Soumendu Majee. "HIGH SPEED IMAGING VIA ADVANCED MODELING." Thesis, 2021.

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There is an increasing need to accurately image objects at a high temporal resolution for different applications in order to analyze the underlying physical, chemical, or biological processes. In this thesis, we use advanced models exploiting the image structure and the measurement process in order to achieve an improved temporal resolution. The thesis is divided into three chapters, each corresponding to a different imaging application.

In the first chapter, we propose a novel method to localize neurons in fluorescence microscopy images. Accurate localization of neurons enables us to scan only the neuron locations instead of the full brain volume and thus improve the temporal resolution of neuron activity monitoring. We formulate the neuron localization problem as an inverse problem where we reconstruct an image that encodes the location of the neuron centers. The sparsity of the neuron centers serves as a prior model, while the forward model comprises of shape models estimated from training data.

In the second chapter, we introduce multi-slice fusion, a novel framework to incorporate advanced prior models for inverse problems spanning many dimensions such as 4D computed tomography (CT) reconstruction. State of the art 4D reconstruction methods use model based iterative reconstruction (MBIR), but it depends critically on the quality of the prior modeling. Incorporating deep convolutional neural networks (CNNs) in the 4D reconstruction problem is difficult due to computational difficulties and lack of high-dimensional training data. Multi-Slice Fusion integrates the tomographic forward model with multiple low dimensional CNN denoisers along different planes to produce a 4D regularized reconstruction. The improved regularization in multi-slice fusion allows each time-frame to be reconstructed from fewer measurements, resulting in an improved temporal resolution in the reconstruction. Experimental results on sparse-view and limited-angle CT data demonstrate that Multi-Slice Fusion can substantially improve the quality of reconstructions relative to traditional methods, while also being practical to implement and train.

In the final chapter, we introduce CodEx, a synergistic combination of coded acquisition and a non-convex Bayesian reconstruction for improving acquisition speed in computed tomography (CT). In an ideal ``step-and-shoot'' tomographic acquisition, the object is rotated to each desired angle, and the view is taken. However, step-and-shoot acquisition is slow and can waste photons, so in practice the object typically rotates continuously in time, leading to views that are blurry. This blur can then result in reconstructions with severe motion artifacts. CodEx works by encoding the acquisition with a known binary code that the reconstruction algorithm then inverts. The CodEx reconstruction method uses the alternating direction method of multipliers (ADMM) to split the inverse problem into iterative deblurring and reconstruction sub-problems, making reconstruction practical. CodEx allows for a fast data acquisition leading to a good temporal resolution in the reconstruction.

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Chang, Chiu Sen, and 張秋森. "A Study of Cycle Compression Problem on CRMA High Speed Networks." Thesis, 1994. http://ndltd.ncl.edu.tw/handle/61808610946468451498.

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碩士
國立清華大學
資訊科學學系
82
Cyclic-Reservation Multiple-Access (CRMA) is an access scheme for high-speed local and metropolitan area networks based on a dual-bus configuration. CRMA provides high throughput efficiency and fairness independent of the network speed or distance. In CRMA, the headend generates the reserve commands periodically. Each station reserves a number of slots in each reserve command if necessary. The headend will generate a sequence of cycles each of which is used to service the reservations on the corresponding reserve command. The length of each cycle is equal to the total number of slots reserved by the stations in the corresponding reserve command. Generally, a longer cycle length will conduct a longer access delay and a lower slots utilization. It is desirable to have a scheme to make the cycle length as short as possible. In this dissertation, we prove that the problem of finding a shortest cycle for a CRMA reservation (called as cycle compression problem) is NP-complete by showing that it is equivalent to the interval coloring problem. We also propose an O(n^2) approximation algorithm to solve this problem; where n is the number of stations in the network. The effectiveness of the algorithm is evaluated via simulation. Simulations results show that compared to the traditional CRMA reservation scheme, the new scheme makes a much shorter cycle length and hence the obtained throughput is much better than the traditional scheme.

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Shin, Bonghun. "High-Speed Probe Card Analysis Using Real-time Machine Vision and Image Restoration Technique." Thesis, 2013. http://hdl.handle.net/10012/7803.

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There has been an increase in demand for the wafer-level test techniques that evaluates the functionality and performance of the wafer chips before packaging them, since the trend of integrated circuits are getting more sophisticated and smaller in size. Throughout the wafer-level test, the semiconductor manufacturers are able to avoid the unnecessary packing cost and to provide early feedback on the overall status of the chip fabrication process. A probe card is a module of wafer-level tester, and can detect the defects of the chip by evaluating the electric characteristics of the integrated circuits(IC's). A probe card analyzer is popularly utilized to detect such a potential probe card failure which leads to increase in the unnecessary manufacture expense in the packing process. In this paper, a new probe card analysis strategy has been proposed. The main idea in conducting probe card analysis is to operate the vision-based inspection on-the- y while the camera is continuously moving. In doing so, the position measurement from the encoder is rstly synchronized with the image data that is captured by a controlled trigger signal under the real-time setting. Because capturing images from a moving camera creates blurring in the image, a simple deblurring technique has been employed to restore the original still images from blurred ones. The main ideas are demonstrated using an experimental test bed and a commercial probe card. The experimental test bed has been designed that comprises a micro machine vision system and a real-time controller, the con guration of the low cost experimental test bed is proposed. Compared to the existing stop-and-go approach, the proposed technique can substantially enhance the inspection speed without additional cost for major hardware change.

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Teo, Yik Ren. "Damping and tracking controllers for nanopositioning systems: applications for high-speed scanning probe microscopy." Thesis, 2017. http://hdl.handle.net/1959.13/1351738.

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Research Doctorate - Doctor of Philosophy (PhD)
Nanopositioning systems are electromechanical devices that provide displacement with atomic- scale accuracy over a range of 10 to 1000 um. They are essential in a variety of scientific and industrial applications, such as in biological cell microinjection, nanoassembly and scanning probe microscopy. The wide application range introduces challenges for the design and control of nanopositioning systems, where the goals are a long travel range, high resonance frequency, high resolution and high bandwidth. However, as these goals are contradictory, compromises are inevitable. The first section of the study focusses on the control design methodologies that improve the perfor- mances of nanopositioning systems. The main limitation is due to the lightly damped resonance modes in the system which results in a low gain margin. A new damping control scheme is proposed to deal with the lightly damped resonance modes. This is paired with a Structured PI controller, and the tracking performance outperforms a standard PID controller when tested on a commercial objective lens positioner. Periodic references are commonly applied to nanopositioning systems. Hence, the tracking per- formances of such references are of interest. Improvements to Repetitive Control (RC), a popular controller for period reference, are described. RC schemes are normally paired with inverse and ro- bustness filters to maximise the tracking performance. A new method for synthesising the inverse filters is presented which is simpler, consistent and more efficient than the existing methods in the literature. In addition, the design process of the robustness filter is at present ad-hoc. This process is replaced with an automated process based on a convex optimisation and an uncertainty model. Experimental results are presented throughout to clarify and validate the concepts presented. The second section of the study focuses on scanning methods for scanning probe microscopy. The scanning method is shown to directly affect the accuracy of the positioning and the image quality. Hence, the scanning methods in the literature are reviewed and quantitatively analysed for performance. The relationships between the imaging quality and the scanning method are also examined. The theoretical predictions are accompanied by simulation and experimental results from a commercial atomic force microscope.

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Than, Van-The, and 申文勢. "On an inverse method for analyzing thermal problems in a high-speed spindle." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/naks88.

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博士
逢甲大學
機械與航空工程博士學位學程
105
Because of continuously working for long time, a high-speed spindle with angular contact ball bearings may be heated and further lead to failure under thermal effects. Typically, heat sources in the spindle come from bearing friction torque and built-in motor. To estimate heat sources of the spindle, this thesis intends to develop an inverse method combined finite element (FE) model and conjugate gradient method (CGM). In the method, traditional mathematical equations are replaced by the FE model which appropriates for modeling a complex structure and consisting different materials as the high-speed spindle. The present method features a high efficiency solution to direct and inverse problems, in which the embedded algorithm is simplified by elimination of solving adjoint and sensitivity problems. A discussion of computational time and mesh size for the model is given. Some simulation cases are performed to demonstrate the inverse method. Results show that based on only two measurement points, the method can accurately obtain inverse results that agree well with exact solutions even if measurement noise is involved. Experimental temperatures are then employed to carry out and validate the inverse solutions. A well correlation between the measured and estimated temperatures is displayed. In addition, the heat generation prediction is satisfactory, and temperatures from the proposed inverse method are consistent with measured temperatures at the verification points. These results demonstrate that the proposed method has a strong potential for estimating the heat sources in a complex structure which is blended different materials. High-speed ball bearing plays an important role in high-speed spindles. However, its characteristics are often influenced by speed and thermal effects. An approach that combines an inverse method with a high-speed ball bearing model to determine characteristics of a high-speed spindle bearing under constant preload in actual working conditions is presented. With temperature distribution in the entire spindle obtained by the experimental inverse heat transfer model from the results of chapter 3, the change in bearing parameters is then calculated and subsequently replaced in the bearing model to analyze the change in bearing characteristics. As a result, thermal effects on a bearing’s dynamic contact angles, contact forces, contact stress, stiffness and lubricant film thickness are presented. Moreover, analysis results indicate that a bearing’s stiffness and lubricant film thickness nonlinearly vary with the increase in speed, and the thermal effect significantly affects the lubricant film thickness. The results presented herein may be applied to develop a dynamic model for a high-speed spindle using a constant preload and provide useful information to avoid failure in lubrication. There are two kinds of preload employed in the spindle that are constant and fixed-position preloads. Therefore, the bearing characteristics are continuously investigated for case of fixed-position preload. A new algorithm based on high-speed bearing model and finite different method is established to completely analyze the change of thermal contact resistance, bearing parameters, heat sources, and bearing stiffness. The bearing parameters and lubricant viscosity affected by time-varying temperature are updated in each time step. As a result, the thermal effects on contact angles, contact forces, the preload, and stiffness of the bearing are found. Moreover, analysis results show that the estimated preload and bearing stiffness nonlinearly vary with the increase in temperature. Thus, it can conclude that bearing characteristics change due to nonlinear thermal effects. Present results can be adopted to gain the precision of the high-speed spindle model. To broaden the consideration of thermal influence, prediction of axial thermal error is further carried out for a micro high-speed motorized spindle. Based on measured temperatures, an inverse method is applied to obtain the heat source and temperature field in the spindle. The temperature results demonstrate that there exists a uniform temperature distribution along the axial direction within the motor range. Hence, a simple one-dimensional heat transfer model is established to acquire the temperature and resulting thermal errors. Displacement jumps when the spindle starts and stops; the nonlinear deformation on the bearings is satisfactorily treated in the model. The results show that the estimated thermal errors agree with the measured data for both constant and various speeds. In addition, the results reveal that spindle speed significantly affects the maximum thermal error. A short processing time is an advantage of the proposed method. The model promises effective integration in machine tools for compensating thermal errors.

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Tsai, Tzung-Yi, and 蔡宗益. "A high speed, high resolution Hand-held Probe Based Optical Coherence Tomographic System for in vivo Microstructure and Angiographic Imaging." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/aamkdm.

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碩士
國立陽明大學
生醫光電研究所
105
Clinically, there uses a biopsy to detect oral cancer. However, this is too painful for the patient and often mistaken for inflammation rather than cancer. The disadvantage will reduce the patient's willingness to keep treatment. Thus, the goal of this study is to develop an advanced diagnostic instrument for earlier detection of oral cancer. We developed a hand-held oral probe system for in vivo ultrahigh speed optical coherence tomography (OCT) and angiographic imaging of the oral tissue without any contrast agents. Using a 1310 nm swept source laser, the system has a 100 kHz A-scan rate and ~12.11 um axial resolution in air. The system enables two-dimensional imaging of the sample at 100 frames per second (fps) with a ~8.77 um lateral resolution. Volumetric data consisting of 370 two-dimensional images of 1,000 A-scans each over a 3 mm length, covering a ~9 mm2 area is acquired in ~30 seconds. OCT angiography (OCTA) is computed using intensity decorrelation between sequential pairs of two-dimensional scans and enables three-dimensional visualization of micro-vasculature. Volumetric OCT, OCTA imaging and tissue thickness of the mice tongue, wound healing of mice ears with angiogenesis, human lip in vivo were demonstrated.

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Hsieh, Yu-Cheng, and 謝宇程. "The Exploration of the Interaction Problems of Online Ticketing Systems ─ An Example of Taiwan High Speed Rail." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/25156311008323434308.

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碩士
國立屏東科技大學
工業管理系所
97
Due to the rapid development of Internet technology and the popular of using Internet, more and more travelers take advantage of online ticketing systems buying tickets. The media and the statistics show that there are many problems on using Taiwan High Speed Railway（THSR） online ticketing systems and its utilization rate is extreme low. The previous researches of online ticketing systems based on quantitative methods of measured interface usability. This study based on qualitative methods（observation and focus groups） explores the interaction between travelers and the THSR online ticketing systems. This study found most traveler did not favorite this systems due to difficulties and problems on using online ticketing systems. The results of this study show that "ask-answer interaction" between traveler and the online ticketing systems is the underlying problem.

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37

Tsai, Che-Yi, and 蔡徹逸. "The Exploration of the Interaction Problems of Ticket Vending Machines ─ An Example of Taiwan High Speed Rail." Thesis, 2009. http://ndltd.ncl.edu.tw/handle/13953782588933970846.

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碩士
國立屏東科技大學
工業管理系所
98
Due to the rapid development of automation technology, more and more travelers take advantage of ticket vending machines (TVMs) to buy tickets. According to the statistics of newspaper and media reports, the TVMs of Taiwan High Speed Railway Company have usability problems and their utilization rate is low. In order to explore the reasons for the ticket vending machine problem, this study uses observation and focus groups to explore the interaction between traveler and TVM. The results show that the key problem of traveler-TVM interaction is "one question-and-one answer" approach. The design approach causes difficulties and problems when travelers using TVMs. Finally, design principles for TVM design are proposed: (1) to prevent errors and to strengthen management; (2) information content label and hardware should be complete; (3) to avoid inconsistencies in design; (4) to provide safe and effective system function; (5) layout and process make proper arrangements.

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38

Feng, Chen-I., and 馮正義. "Performance Analysis of DCS-1800 in the Environment of High Speed Railway with Application of Satellite Transmission for Solving the Fast Fading Problems." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/75810670133485379787.

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碩士
國立東華大學
電機工程學系
94
Abstract Taiwan High Speed Rail will become operational at the end of this year, and the maximum operating speed of the train can reach up to 300 kilometers per hour. Therefore, there is no doubt to be a serious challenge for mobile wireless communications industry to maintain a reliable communication quality under high speed ambiance for commuter of the bullet train. Global System for Mobile (GSM) has been widely adopted since 1992 and offers voicemail, instant message and GPRS functions. Although the vigorous construction of third generation mobile systems (3G) and its base stations are setting out like wildfire amongst the telecommunication corporation in nowadays Taiwan, according to studies, 70% of cellular phone users still use GSM systems since 3G has not been widely accepted because of higher fare rate and less-popularized network. The 3G network is still not prevalent on the island; people mainly use the voice service through GSM service because the rates are less expensive. Moreover, GSM has already set up a compact network on the island and it is therefore still the mainstream of nowadays mobile telecommunication system. This thesis will test the DCS-1800(GSM-1800) under high speed conditions and to overcome the problems of the DCS-1800 in the Taiwan High Speed Rail ambiance. Foremost among these solutions is that the base station should be located on the train. We will connect BTS and BSC via the satellite communication under the Abis interface to solve the problems of connection under high speed rail conditions. At the same time, we must consider that using a geostationary satellite and the feasibilities to estimate the analysis. We have concluded the argument put forth in this thesis will demonstrate a framework that will provide the better system solution, if the satellite have no shielding, no inter-symbol interference and under the ideal weather conditions. The Abis interface overall Eb/No is about 13 dB and analysis results of the receiver signal bit error rate is less than which exhibits that transmission from BTS to BSC via GEO satellite is feasible on this framework.

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Chen, Kuei-Yen, and 陳奎言. "A Study on Investigating Resource Combination Problem of Supply Chain Model of FPLM Using Dynamic Simulation Analysis- A Case Study C260 of Taiwan High Speed Rail Project." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/00767969892223317592.

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碩士
國立雲林科技大學
營建工程系碩士班
93
Full-span Precast Launching Method (FPLM) is a brand new construction technic that imported by Taiwan High Speed Rail Co.. It is produced by pre-concreted completely so that the FPLM is not affected by the weather during the production. However it is depend on the substructure construction/curing completed before the deck launched that FPLM could be developed smoothly or not. You can find out it is the major temporary work, such as formwork, rebar jig, equipment etc. during the FPLM construction, in which the cost of the inner mould and outer form of box girder, the steel form of pier and pierhead of substructure, the rebar jig as well as the launching equipments are quite high. The quantity of those equipments was always depended on experience in the pass time. Therefore the more of the form quantity is used the higher of direct costs would be spent. On the other hand it would be reduced the capacity of production if the equipments are insufficient. What we concern is how to choose the best combination from thousands of different arrangements, that can both increase the production capacity and reduce the direct cost. The research is focus on the supply behavior from the manufacture and production of substructure and box girder to the precast yard and the material supplier under the satisfaction of safety stock of precast yard. Besides, the research also used software of SIMPROCESS for dynamic simulation tool to display the production process and supply behavior, Further more, the research also try to find out major affected factor of whole system to compare the difference between span numbers and progress. Finally, the research will try to use the solution of optimization for the purpose of quick searching of solution to find the best combination of resource and cost of FPLM for the decision of strategic importance of user in the future.

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Dissertations / Theses on the topic 'High Speed Probes'

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