Tesis sobre el tema "Frequency transfer"
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Butler, Brandon. "Reliable data transfer via frequency transmission". Thesis, Butler, Brandon (2017) Reliable data transfer via frequency transmission. Honours thesis, Murdoch University, 2017. https://researchrepository.murdoch.edu.au/id/eprint/40398/.
Texto completoIlvedson, Corinne Rachel 1974. "Transfer function estimation using time-frequency analysis". Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/50472.
Texto completoIncludes bibliographical references (p. 135-136).
Given limited and noisy data, identifying the transfer function of a complex aerospace system may prove difficult. In order to obtain a clean transfer function estimate despite noisy data, a time-frequency analysis approach to system identification has been developed. The method is based on the observation that for a linear system, an input at a given frequency should result in a response at the same frequency, and a time localized frequency input should result in a response that is nearby in time to the input. Using these principles, the noise in the response can be separated from the physical dynamics. In addition, the impulse response of the system can be restricted to be causal and of limited duration, thereby reducing the number of degrees of freedom in the estimation problem. The estimation method consists of finding a rough estimate of the impulse response from the sampled input and output data. The impulse response estimate is then transformed to a two dimensional time-frequency mapping. The mapping provides a clear graphical method for distinguishing the noise from the system dynamics. The information believed to correspond to noise is discarded and a cleaner estimate of the impulse response is obtained from the remaining information. The new impulse response estimate is then used to obtain the transfer function estimate. The results indicate that the time-frequency transfer function estimation method can provide estimates that are often less noisy than those obtained from other methods such as the Empirical Transfer Function Estimate and Welch's Averaged Periodogram Method.
by Corinne Rachel Ilvedson.
S.M.
Lawson, James. "High frequency electromagnetic links for wireless power transfer". Thesis, Imperial College London, 2017. http://hdl.handle.net/10044/1/54841.
Texto completoForeman, Seth M. "Femtosecond frequency combs for optical clocks and timing transfer". Connect to online resource, 2007. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3273700.
Texto completoZhao, Rui. "Double resonant high-frequency converters for wireless power transfer". Thesis, University of Sheffield, 2018. http://etheses.whiterose.ac.uk/22958/.
Texto completoMarra, Giuseppe. "Transfer of optical frequency combs over optical fibre links". Thesis, University of Southampton, 2013. https://eprints.soton.ac.uk/350220/.
Texto completoBoaventura, Alírio de Jesus Soares. "Efficient wireless power transfer and radio frequency identification systems". Doctoral thesis, Universidade de Aveiro, 2016. http://hdl.handle.net/10773/17374.
Texto completoIn the IoT context, where billions of connected objects are expected to be ubiquitously deployed worldwide, the frequent battery maintenance of ubiquitous wireless nodes is undesirable or even impossible. In these scenarios, passive-backscatter radios will certainly play a crucial role due to their low cost, low complexity and battery-free operation. However, as passive-backscatter devices are chiefly limited by the WPT link, its efficiency optimization has been a major research concern over the years, gaining even more emphasis in the IoT context. Wireless power transfer has traditionally been carried out using CW signals, and the efficiency improvement has commonly been achieved through circuit design optimization. This thesis explores a fundamentally different approach, in which the optimization is focused on the powering waveforms, rather than the circuits. It is demonstrated through theoretical analysis, simulations and measurements that, given their greater ability to overcome the built-in voltage of rectifying devices, high PAPR multi-sine (MS) signals are capable of more efficiently exciting energy harvesting circuits when compared to CWs. By using optimal MS signals to excite rectifying devices, remarkable RF-DC conversion efficiency gains of up to 15 dB with respect to CW signals were obtained. In order to show the effectiveness of this approach to improve the communication range of passive-backscatter systems, a MS front-end was integrated in a commercial RFID reader and a significant range extension of 25% was observed. Furthermore, a software-defined radio RFID reader, compliant with ISO18000-6C standard and with MS capability, was constructed from scratch. By interrogating passive RFID transponders with MS waveforms, a transponder sensitivity improvement higher than 3 dB was obtained for optimal MS signals. Since the amplification and transmission of high PAPR signals is critical, this work also proposes efficient MS transmitting architectures based on space power combining techniques. This thesis also addresses other not less important issues, namely self-jamming in passive RFID readers, which is the second limiting factor of passive-backscatter systems. A suitable self-jamming suppression scheme was first used for CW signals and then extended to MS signals, yielding a CW isolation up to 50 dB and a MS isolation up 60 dB. Finally, a battery-less remote control system was developed and integrated in a commercial TV device with the purpose of demonstrating a practical application of wireless power transfer and passive-backscatter concepts. This allowed battery-free control of four basic functionalities of the TV (CH+,CH-,VOL+,VOL-).
No contexto da internet das coisas (IoT), onde são esperados bilhões de objetos conectados espalhados pelo planeta de forma ubíqua, torna-se impraticável uma frequente manutenção e troca de baterias dos dispositivos sem fios ubíquos. Nestes cenários, os sistemas radio backscatter passivos terão um papel preponderante dado o seu baixo custo, baixa complexidade e não necessidade de baterias nos nós móveis. Uma vez que a transmissão de energia sem fios é o principal aspeto limitativo nestes sistemas, a sua otimização tem sido um tema central de investigação, ganhando ainda mais ênfase no contexto IoT. Tradicionalmente, a transferência de energia sem-fios é feita através de sinais CW e a maximização da eficiência é conseguida através da otimização dos circuitos recetores. Neste trabalho explora-se uma abordagem fundamentalmente diferente, em que a otimização foca-se nas formas de onda em vez dos circuitos. Demonstra-se, teoricamente e através de simulações e medidas que, devido à sua maior capacidade em superar a barreira de potencial intrínseca dos dispositivos retificadores, os sinais multi-seno (MS) de elevado PAPR são capazes de excitar os circuitos de colheita de energia de forma mais eficiente quando comparados com o sinal CW tradicional. Usando sinais MS ótimos em circuitos retificadores, foram verificadas experimentalmente melhorias de eficiência de conversão RF-DC notáveis de até 15 dB relativamente ao sinal CW. A fim de mostrar a eficácia desta abordagem na melhoria da distância de comunicação de sistemas backscatter passivos, integrou-se um front-end MS num leitor RFID comercial e observou-se um aumento significativo de 25% na distância de leitura. Além disso, desenvolveu-se de raiz um leitor RFID baseado em software rádio, compatível com o protocolo ISO18000-6C e capaz de gerar sinais MS, com os quais interrogou-se transponders passivos, obtendo-se ganhos de sensibilidade dos transponders maiores que 3 dB. Uma vez que a amplificação de sinais de elevado PAPR é uma operação crítica, propôs-se também novas arquiteturas eficientes de transmissão baseadas na combinação de sinais em espaço livre. Esta tese aborda também outros aspetos não menos importantes, como o self-jamming em leitores RFID passivos, tido como o segundo fator limitativo neste tipo de sistemas. Estudou-se técnicas de cancelamento de self-jamming CW e estendeu-se o conceito a sinais MS, tendo-se obtido isolamentos entre o transmissor e o recetor de até 50 dB no primeiro caso e de até 60 dB no segundo. Finalmente, com o objetivo de demonstrar uma aplicação prática dos conceitos de transmissão de energia sem fios e comunicação backscatter, desenvolveu-se um sistema de controlo remoto sem pilhas, cujo protótipo foi integrado num televisor comercial a fim de controlar quatro funcionalidades básicas (CH+,CH-,VOL+,VOL-).
Hopper, David J. "Investigation of laser frequency stabilisation using modulation transfer spectroscopy". Thesis, Queensland University of Technology, 2008. https://eprints.qut.edu.au/16667/1/David_John_Hopper_Thesis.pdf.
Texto completoHopper, David J. "Investigation of laser frequency stabilisation using modulation transfer spectroscopy". Queensland University of Technology, 2008. http://eprints.qut.edu.au/16667/.
Texto completoHeikkinen, Jouko. "TELEMETRY AND RADIO FREQUENCY IDENTIFICATION". International Foundation for Telemetering, 1999. http://hdl.handle.net/10150/607334.
Texto completoComparison of short-range telemetry and radio frequency identification (RFID) systems reveals that they are based on very similar operating principles. Combining the identification and measurement functions into one transponder sensor offers added value for both RFID and telemetry systems. The presence of a memory (e.g. FRAM) in the transponder, required for ID information, can also be utilized for storing measurement results. For passive transponders low power consumption is one of the main objectives. Wireless power transfer for passive transponder sensors together with above aspects concerning a combined telemetry and identification system are discussed.
Andrews, Seth Dixon. "Extensions to Radio Frequency Fingerprinting". Diss., Virginia Tech, 2019. http://hdl.handle.net/10919/95952.
Texto completoDoctor of Philosophy
Radio frequency fingerprinting allows uniquely identifying a transmitter based on characteristics of the signal it emits. In this dissertation several extensions to current fingerprinting techniques are given. Together, these allow identification of transmitters which have changed the signal sent, identifying using different measurement types, and compensating for variation in a transmitter's behavior due to changes in temperature.
Terassa, Laura Anna Maria [Verfasser], Christian [Akademischer Betreuer] Mair y Bernd [Akademischer Betreuer] Kortmann. "Morphological simplification in Asian Englishes : : frequency, substratum transfer, and institutionalization". Freiburg : Universität, 2019. http://d-nb.info/1178321495/34.
Texto completoOyeka, Dumtoochukwu Obiora. "Digitally fabricated epidermal transfer tattoo UHF radio frequency identification tags". Thesis, University of Kent, 2015. https://kar.kent.ac.uk/56651/.
Texto completoKapoor, Gaurav. "Secure ownership transfer and authentication protocols for Radio Frequency Identification (RFID)". [Gainesville, Fla.] : University of Florida, 2008. http://purl.fcla.edu/fcla/etd/UFE0022783.
Texto completoMaschino, Tyler Stephen. "FREQUENCY-SELECTIVE DESIGN OF WIRELESS POWER TRANSFER SYSTEMS FOR CONTROLLED ACCESS APPLICATIONS". Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1461787114.
Texto completoDroste, Stefan [Verfasser]. "Optical frequency transfer via telecommunication fiber links for metrological applications / Stefan Droste". Hannover : Technische Informationsbibliothek und Universitätsbibliothek Hannover (TIB), 2014. http://d-nb.info/1065397607/34.
Texto completoCaldas, Fernando Pinto. "Drying of granulated products by conventional heat transfer and high-frequency techniques". Thesis, Loughborough University, 1988. https://dspace.lboro.ac.uk/2134/35994.
Texto completoDodson, Kathryn Kristine. "Transfer Frequency of CMY-2-Encoding Plasmids Among Fecal Flora of Pigs". The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1395851225.
Texto completoSchulte, Walter B. III. "The frequency response, impulse response, and transfer function of an ocean waveguide". Thesis, Monterey, California. Naval Postgraduate School, 2004. http://hdl.handle.net/10945/1516.
Texto completoIn this thesis, the ocean was modeled as a waveguide with an ideal pressure - release surface, and an ideal rigid bottom. The ocean waveguide was then treated as a linear, time - invariant, space - variant (TISV) filter or communication channel. The filter is time - invariant because no motion was modeled and because the properties of the ocean were assumed to be constant. The filter is space - variant because of the presence of the two boundaries, that is, the ocean surface and ocean bottom. This thesis investigates the ocean as a linear TISV filter by evaluating 1) the complex frequency response, 2) the impulse response, and 3) the transfer function of the ocean with respect to depth. It is shown that the TISV impulse response of the ocean contains information that can be used to help localize a target in range and whether the target is above or below the receiver. Computer simulation results were obtained by evaluating the three filter functions for several different test cases.
Ensign, United States Navy
Schulte, Walter B. "The frequency response, impulse response, and transfer function of an ocean waveguide /". Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FSchulte.pdf.
Texto completoThesis advisor(s): Lawrence J. Ziomek. Includes bibliographical references (p. 47). Also available online.
Djurberg, Axel, Fredrik Forsberg, Anton Lind y Ludvig Snihs. "Wireless Power Transfer in Cavity Resonator". Thesis, Uppsala universitet, Fasta tillståndets elektronik, 2021. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-444250.
Texto completoPANDEY, AJIT K. "RADIO-FREQUENCY ABLATION IN A RECONSTRUCTED REALISTIC HEPATIC TISSUE". University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1061210342.
Texto completoMcCune, Robert E. "Identification of Continuous-Time and Discrete-Time Transfer Function Models from Frequency Response Measurements". Ohio University / OhioLINK, 1989. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1239731009.
Texto completoLalonde, Jasmin. "Task-dependent transfer of perceptual to memory representations during delayed spatial frequency discrimination". Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=33911.
Texto completoAlagappan, Azhagammai. "Studies of collisional energy transfer in the CN radical by frequency-modulated spectroscopy". Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/62.
Texto completoSenturk, Sabri. "Experimental Determination Of Transfer Functions For A Car Body-in-white". Master's thesis, METU, 2004. http://etd.lib.metu.edu.tr/upload/12604899/index.pdf.
Texto completos dynamic characteristics that act as vibration transfer channels. In the previous study, a finite element model has been created for a car body-in-white available in Automotive Laboratory (Mechanical Engineering Department, Middle East Technical University, Ankara) and its natural frequencies and mode shapes have been determined using finite element analysis software. In this study, vibration tests have been performed on actual car body-in-white. Frequency response functions between 34 response locations and force application point have been measured. Using these frequency response functions, natural frequencies and mode shapes of the body-in-white have been determined. Finite element analysis and experimental results have been compared to evaluate the finite element model reliability.
Zhao, Yanzhu. "Metal-transfer-molding (MTM) technique for micromachined RF components". Diss., Atlanta, Ga. : Georgia Institute of Technology, 2008. http://hdl.handle.net/1853/24750.
Texto completoCommittee Chair: Mark G. Allen; Committee Member: J. Stevenson Kenney; Committee Member: Joy Laskar; Committee Member: Oliver Brand; Committee Member: Peter Hesketh.
Fotopoulou, Kyriaki. "Inductive wireless power transfer for RFID & embedded devices : coil misalignment analysis and design". Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/10907.
Texto completoYang, Shuai. "Alternative power transfer for passive RFID systems in challenging applications". Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/270885.
Texto completoSharma, Ragahv. "Behavioral Modeling and FPGA Synthesis of IEEE 802.11n Orthogonal Frequency Division Multiplexing (OFDM) Scheme". Scholar Commons, 2016. http://scholarcommons.usf.edu/etd/6584.
Texto completoPathmanathan, Shaetrun. "Development and analysis of wireless power transfer communication systems for left Ventricular Assist Devices". Thesis, Queensland University of Technology, 2022. https://eprints.qut.edu.au/229220/1/Shaetrun_Pathmanathan_Thesis.pdf.
Texto completoBabendreier, Justin Eric. "Near aggregation: a time and frequency domain analysis using state trajectories and transfer function residues". Thesis, Virginia Polytechnic Institute and State University, 1987. http://hdl.handle.net/10919/91080.
Texto completoM.S.
He, Shujian. "A TRANSFER MATRIX APPROACH TO DETERMINE THE LOW FREQUENCY INSERTION LOSS OF ENCLOSURES INCLUDING APPLICATIONS". UKnowledge, 2017. https://uknowledge.uky.edu/me_etds/104.
Texto completoFayon, Lucile. "Instrumentation sismologique spatiale : Fonction de transfert du sismomètre 6 axes InSight et développement d'un capteur de déplacement picométrique par interférométrie". Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC099/document.
Texto completoThe understanding of the Solar System formation and its evolution is deeply connected to the knowledge on the planet interior structures. In situ studies with seismometers are therefore crucial to probe the internal structure (distribution and thickness of layers) and composition of the telluric planets. Indeed, SEIS (Seismic Experiment for Interior Structure) will land on Mars in 2018 (NASA InSight mission). Both types of sensors of the SEIS instrument, the VBB (Very Broad Band) and SP (Short Period), are mounted on the LVL (a mechanical levelling system) for which the purpose is twofold: ensure a level placement of the sensors on the Martian ground under yet unknown local conditions and provide the mechanical coupling of the seismometers to the ground. In this thesis, we developed a simplified analytical model of the LVL structure in order to reproduce its mechanical behaviour by predicting its resonances and transfer function. This model will allow to estimate the LVL effect on the VBB and SP data recorded on Mars. It is first implemented numerically and its validation is then guaranteed thanks to the observation of a lot of similarities between our results and those of the laboratory experiments with the LVL flight model. These comparisons prove the model fidelity with reality. After some simulations, we noticed a clear influence of the mechanical coupling between the LVL feet and the ground in the resonances found. For this reason, an inversion study has been realized in order to study if this model could allow to estimate the ground properties of the InSight site. Another work consists in modeling the 3 VBB sensors and the 3 SP sensors on the LVL and to observe the response of the global SEIS instrument in translation and rotation. Indeed, some rotation effects at short period can disturb the seismic measurements. This study can also allows to estimate the performances of SEIS, especially in rotation that can be one important information to recover the phase velocity of the surface seismic waves, highly dependent of the ground composition. This can be realized on Mars with an active seismic experiment thanks to the other main instrument of InSight mission: HP3. Today, new projects are also considered for a seismic return on the Moon. Indeed, the Apollo seismometers had a good resolution in ground displacement but were however unable to detect the Lunar ground seismic noise, named "meteoritic hum". This noise is possibly due to the continuous fall of micro-meteorites and its amplitude has been estimated to be about 1/100 of the resolution of the Apollo sensors at a certain frequency. Core seismic phases, although detected through stacking, have not also been individually recorded. A new generation of broadband seismometers, 100 to 1000 times more sensitive than the Apollo ones are therefore requested in order to reach the lunar seismic noise floor. This sensitivity will allow to take benefit of all the seismic waves generated by the Moon seismic activity. The core of such seismometer will be the proof mass displacement sensors, with extreme improvement in performances, linearity and noise level. During this thesis, we developed an optical readout prototype, based on the use of gravitational waves detectorsÕ technology which is the reference in term of interferometric measurements at low frequency and very low noise levels. This prototype is based on the "Pound-Drever-Hall" laser frequency stabilization technique. The objective is to improve the sensitivity by 2 orders of magnitude compared to the current seismometers performances
Feng, Junjie. "6.78MHz Omnidirectional Wireless Power Transfer System for Portable Devices Application". Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/101839.
Texto completoDoctor of Philosophy
Wireless power transfer (WPT) is a promising solution to deliver power to a battery in a variety of applications. Due to its convenience, wireless power transfer technology with loosely coupled coils has become popular in consumer electronics. In such system, the receiving coil embedded in the receiving device picks up magnetic field induced by the transmitter coil; therefore, energy is transferred through the magnetic field and contactless charging is achieved. Thus far, the majority of the coupled coils in these systems are planar structure, and the magnetic field induced by the transmitter coil is in one direction, meaning that the energy power transfer capability degrades greatly when there is some angle misalignment between the coupled coils. To improve the charging flexibility, a three–dimensional (3D) coils structure is proposed to transfer energy in different directions, also known as in omnidirectional manner. With omnidirectional magnetic field, the charging platform can provide energy transfer in any direction; therefore, the angle alignment between the transmitter coil and receiver coil is no longer needed. In a WPT system with loosely coupled coils, the energy transfer capability suffers from weak coupling condition. To improve the power transfer capability, the electrical resonance concept between the inductor and capacitor at the power transfer frequency is adopted. A novel compensation network is proposed to form a resonant tank with the loosely coupled coils and maximize the power transfer at the operating frequency. As for the WPT system with loosely coupled coils, the energy transfer capability is also proportional to the operating frequency. Therefore, Megahertz (MHz) WPT systems are used to improve the charging spatial freedom. 6.78 MHz is selected as the system operation in AirFuel standard, a wireless charging standard for commercial electronics. The zero voltage switching (ZVS) operation of the switching devices is essential in reducing the switching loss and the switching related electromagnetic interference (EMI) issue in a MHz system; therefore, a comprehensive evaluation of ZVS condition in an omnidirectional WPT system is performed. The big hurdle of the WPT technology is the safety concern related to human exposure of electromagnetic fields (EMF). Therefore, a double layer shield structure is first applied in a three dimensional charging setup to confine the electromagnetic fields effectively. The stray field level in our charging platform is well below the safety level required by the regulation agent. Although the energy can be transferred in an omnidirectional manner in the proposed charging platform, the energy should be directed to the target loads to avoid unnecessary energy waste. Therefore, a smart detection method is proposed to detect the receiver coil's orientation and focus the energy transfer to certain direction preferred by the receiver in the setup. The energy beaming strategy greatly improves the charging speed of the charging setup.
Mohieldin, Ahmed Nader. "High performance continuous-time filters for information transfer systems". Texas A&M University, 2003. http://hdl.handle.net/1969/233.
Texto completoDöringshoff, Klaus. "Optical frequency references based on hyperfine transitions in molecular iodine". Doctoral thesis, Humboldt-Universität zu Berlin, 2018. http://dx.doi.org/10.18452/19156.
Texto completoThis thesis deals with the development and investigation of optical absolute frequency references based on rovibronic transitions in molecular iodine. Doppler-free saturation spectroscopy methods are employed to resolve individual transitions of the hyperfine structure with linewidths below 1 MHz in the B-X system of molecular iodine at 532 nm with the second harmonic of Nd:YAG lasers. Electronic feedback control systems are employed for laser frequency stabilization to the line center of the optical transitions with a line splitting of 10^5. With the goal of a space qualified optical absolute frequency reference for future laser-interferometric space missions, two spectroscopy setups were designed and realized in quasi-monolithic, glass-ceramic setups as so called elegant bread board model and engineering model. These iodine references were characterized in detail with respect to their frequency stability and reproducibility and the engineering model was subject to environmental tests, including vibrations and thermal cycling to verify its applicability in future space missions. For the investigation of the frequency instability of these iodine references, a frequency stabilized laser system was realized based on a temperature controlled high Finesse ULE cavity for direct frequency comparisons at 1064 nm. Analysis of the frequency stability of the iodine references revealed exceptionally low fractional frequency instability of 6x10^−15 at 1 s, averaging down to less than 2×10^−15 at 100 s integration time, constituting the best reported stability achieved with iodine references to date. With the demonstrated performance, these absolute frequency references enable precision laser systems required for future space missions that are dedicated to, e.g., the detection of gravitational waves, mapping of the Earth’s gravitational field or precision test of fundamental physics.
Wang, Ce. "Study on Novel Rectifiers for Microwave Wireless Power Transfer System". Kyoto University, 2020. http://hdl.handle.net/2433/253503.
Texto completoDeLong, Brock J. "Integration of Radio Frequency Harvesting with Low Power Sensors". The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu152408949118599.
Texto completoBihl, Trevor Joseph. "State Variable System Identification through Frequency Domain Techniques". Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1307128475.
Texto completoRoa, Rodríguez Rodrigo y Robert Lundin. "Heatmap Visualization of Neural Frequency Data". Thesis, KTH, Skolan för datavetenskap och kommunikation (CSC), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186860.
Texto completoKomplexa spatiala mo ̈nster och fo ̈rh ̊allanden i multivariat data a ̈r rel- ativt sv ̊ara att identifiera via bera ̈kningar men simpla att identifiera vi- suellt. Att visualisera data fo ̈r denna typ av data-analys anva ̈nds ofta i m ̊anga olika typer av fa ̈lt. Detta motiverade utvecklingen av Anivis; ett interaktivt verktyg fo ̈r visuell utforskning av multivariat kvantitativ data av neural aktivitet. Anivis anva ̈nder sig av dataset baserade p ̊a experi- mentell data fr ̊an en forskningsgrupp p ̊a Karolinska Institutets Institution fo ̈r Neurovetenskap. Dessa fyrdimensionella dataset best ̊ar av ma ̈tningar fr ̊an neuroner i form av deras position, aktivitet i form av frekvens och tidpunkt. Denna data anva ̈nds fo ̈r att generera en animerad heatmap, da ̈r neuroners frekvensva ̈rden visas i form av f ̈arg. Frekvensva ̈rdena om- vandlades till fa ̈rgva ̈rden via ̈overg ̊angsfunktioner som kopplar numeriska va ̈rden till fa ̈rgva ̈rden via parametriserade kurvor. Anivis lyckades imple- mentera tv ̊a olika metoder f ̈or att generera heatmap, viktade summor och dekonvolution. Dessa tv ̊a metoder ja ̈mfo ̈rdes med varandra, varav dekon- volution visade sig vara den teoretiskt och praktiskt e↵ektivaste meto- den. Utvecklingen av Anivis visade a ̈ven behovet fo ̈r ett punktdiagram fo ̈r att visualisera f ̈orh ̊allandet mellan ma ̈tta frekvensv ̈arden och spatial frekvensfo ̈rdelning i heatmappen.
Shin, Yoon Shik. "Modifications to a two-control-volume, frequency dependent, transfer-function analysis of hole-pattern gas annular seals". Thesis, Texas A&M University, 2005. http://hdl.handle.net/1969.1/4751.
Texto completoHolmberg, David G. "A frequency domain analysis of surface heat transfer/free-stream turbulence interactions in a transonic turbine cascade". Diss., This resource online, 1996. http://scholar.lib.vt.edu/theses/available/etd-06062008-154531/.
Texto completoBirchfield, Neal Spencer. "STRUCTURAL MODIFICATION OF A COUPLED ROTORDYNAMIC SYSTEM FROM TRANSFER FUNCTIONS". Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1376320545.
Texto completoYang, Taeyoung. "Fundamental Limits on Antenna Size for Frequency and Time Domain Applications". Diss., Virginia Tech, 2012. http://hdl.handle.net/10919/39334.
Texto completoPh. D.
Thomas, Edward John. "A C++ class library capable of handling matrix, polynomial, transfer function, state space, and frequency response data types". Ohio : Ohio University, 1995. http://www.ohiolink.edu/etd/view.cgi?ohiou1178902180.
Texto completoSun, Keyao. "Protection, Control, and Auxiliary Power of Medium-Voltage High-Frequency SiC Devices". Diss., Virginia Tech, 2021. http://hdl.handle.net/10919/103743.
Texto completoDoctor of Philosophy
The wide bandgap semiconductor enables next-generation power electronics systems with higher efficiency and higher power density which will reduce the space, weight, and cost for power supply and conversion systems, especially for renewable energy. However, by pushing the system voltage level higher to medium-voltage of tens of kilovolts, although the system has higher efficiency and simpler control, the reliability drops. This dissertation, therefore, focusing on solving the possible overcurrent, overvoltage, and gate failure issues of the power electronics system that is caused by the high voltage and high electromagnetic interference environment. By utilizing the inductance of the device, a dual-protection method is proposed to prevent the overcurrent problem. The overcurrent fault can be detected within tens of nanoseconds so that the device will not be destroyed because of the huge fault current. When multiple devices are connected in series to hold higher voltage, the voltage sharing between different devices becomes another issue. The proposed modeling and control method for series-connected devices can balance the shared voltage, and make the control system stable so that no overvoltage problem will happen due to the non-evenly distributed voltages. Besides the possible overcurrent and overvoltage problems, losing control of the devices due to the unreliable auxiliary power supply is another issue. This dissertation proposed a scalable auxiliary power network with high efficiency, high immunity to electromagnetic interference, and high reliability. In this network, a wireless power transfer converter is designed to provide enough insulation and isolation capability, while a switched capacitor converter is designed to transfer voltage from several kilovolts to tens of volts. With the proposed overcurrent protection method, voltage sharing control, and reliable auxiliary power network, systems utilizing medium-voltage wide-bandgap semiconductor will have higher reliability to be implemented for different applications.
Arias, Diego Alejandro Guzman. "Hydrological risk transfer planning under the drought \"severity-duration-frequency\" approach as a climate change impact mitigation strategy". Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/18/18138/tde-21062018-104407/.
Texto completoAs mudanças climáticas e o incremento na demanda de água priorizam a necessidade de implementar estratégias de planejamento para a segurança hídrica urbana no longo e mediano prazo. No entanto, o planejamento dos riscos exige um suporte financeiro robusto e oportuno durante e após do desastre. Portanto, as ferramentas de transferência de risco, como os seguros, emergem como uma estratégia efetiva para garantir a resiliência financeira e como um elemento que poderia incentivar a implementação de mecanismos de redução do risco hidrológico. Entre os principais problemas no planejamento de seguros, estão a falta de informações sobre os impactos reais das secas e a incerteza climática, que podem levar a seleção adversa e/ou perigo moral como as problemáticas mais comuns na prática dos seguros. Atualmente, a maior parte da renda das empresas de serviços de água é baseada na gestão do recurso hídrico; portanto, durante períodos prolongados de seca, essas economias podem ser fortemente afetadas, apesar de ter sistemas de armazenamento robustos como suporte. Assim, esta tese propõe um plano de seguro para a empresa de serviços de água do Estado de São Paulo (SABESP), para enfrentar as reduções de receita durante longos períodos de seca. A metodologia é implementada no modelo MTRH-SHS, desenvolvido no cálculo \"ex-ante\" de custos de dano, através da abordagem baseada em risco. A abordagem sintética (\"what-if\"), usa um \"conjunto de drivers de mudança\" para estimar o prêmio ótimo através de um contrato de seguro plurianual (SPA). A metodologia integra os procedimentos de simulação hidrológica, sob cenários de forçamento climático radiativo RCP 4.5 e 8.5, do modelo de clima regional Eta-HadGEM e Eta-MIROC5, com horizontes temporais de 2007-2040, 2041-2070 e 2071-2099, vinculados ao modelo hidrológico do sistema de avaliação e planejamento da água (WEAP) e sob pressupostos de demanda como abastecimento de água estacionária e não estacionária. A estrutura do modelo é aplicada ao Sistema de Abastecimento de Água de Cantareira na Região Metropolitana de São Paulo, Brasil, região com alta vulnerabilidade às secas. Como resultado, os índices de rendimento do seguro avaliados mostraram que os contratos plurianuais com cobertura para secas superiores a 240 dias, oferecem melhor desempenho financeiro do que os contratos com coberturas mais amplas. Além, o SPA adotado para o risco residual do armazenamento instalado, gera um nível mais alto de solvência para o fundo de seguros no longo prazo com prêmios médios anuais mais próximos das reduções de receita esperadas por cenário. Finalmente, a abordagem pode ajudar na avaliação sistemática do risco moral e na seleção adversa. No primeiro caso, a avaliação progressiva deve gerar informações úteis para mudar ou manter o comportamento de segurados e seguradoras considerando riscos futuros relacionados à mudança climática. No segundo caso, a valoração de múltiplos cenários pode ajudar a estabelecer limiares de preços, oferecendo opções de cobertura diferencial de risco no valor prêmio de seguro.
Powers, Alex D. "A Study of Constant Voltage Anemometry Frequency Response". DigitalCommons@CalPoly, 2016. https://digitalcommons.calpoly.edu/theses/1570.
Texto completoAllu, Pareekshith. "A Hybrid Ballistic-Diffusive Method to Solve the Frequency Dependent Boltzmann Transport Equation". The Ohio State University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=osu1451998769.
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