Rozprawy doktorskie na temat „Wave localization”
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Rimal, Nischal. "Impact Localization Using Lamb Wave and Spiral FSAT". University of Toledo / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1388672483.
Pełny tekst źródłaVidiyala, Sai Krishna. "Simultaneous localization and mapping with radio signals". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021. http://amslaurea.unibo.it/24138/.
Pełny tekst źródłaLotti, Marina, i Marina Lotti. "Experimental characterization of millimeter-wave radars for mapping and localization". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/19891/.
Pełny tekst źródłaWoolard, Americo Giuliano. "Supplementing Localization Algorithms for Indoor Footsteps". Diss., Virginia Tech, 2017. http://hdl.handle.net/10919/78698.
Pełny tekst źródłaPh. D.
Bordiga, Giovanni. "Homogenization of periodic lattice materials for wave propagation, localization, and bifurcation". Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259019.
Pełny tekst źródłaBordiga, Giovanni. "Homogenization of periodic lattice materials for wave propagation, localization, and bifurcation". Doctoral thesis, Università degli studi di Trento, 2020. http://hdl.handle.net/11572/259019.
Pełny tekst źródłaReinwald, Michael. "Wave propagation in mammalian skulls and its contribution to acoustic source localization". Thesis, Sorbonne université, 2018. http://www.theses.fr/2018SORUS244.
Pełny tekst źródłaThe spatial accuracy of source localization by dolphins has been observed to be equally accurate independent of source azimuth and elevation. This ability is counter-intuitive if one considers that humans and other species have presumably evolved pinnae to help determine the elevation of sound sources, while cetaceans have actually lost them. In this work, 3D numerical simulations are carried out to determine the influence of bone-conducted waves in the skull of a short-beaked common dolphin on sound pressure in the vicinity of the ears. The skull is not found to induce any salient spectral notches, as pinnae do in humans, that the animal could use to differentiate source elevations in the median plane. Experiments are conducted in a water tank by deploying sound sources on the horizontal and median plane around a skull of a dolphin and measuring bone-conducted waves in the mandible. Their full waveforms, and especially the coda, can be used to determine source elevation via a correlation-based source localization algorithm. While further experimental work is needed to substantiate this speculation, the results suggest that the auditory system of dolphins might be able to localize sound sources by analyzing the coda of biosonar echoes. 2D numerical simulations show that this algorithm benefits from the interaction of bone-conducted sound in a dolphin's mandible with the surrounding fats
LaPenta, Jason Michael. "Real-time 3-d localization using radar and passive surface acoustic wave transponders". Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/41738.
Pełny tekst źródłaIncludes bibliographical references (p. 141-150).
This thesis covers ongoing work into the design, fabrication, implementation, and characterization of novel passive transponders that allow range measurements at short range and at high update rates. Multiple RADAR measurement stations use phase-encoded chirps to selectively track individual transponders by triangulation of range and/or angle measurements. Nanofabrication processes are utilized to fabricate the passive surface acoustic wave transponders used in this thesis. These transponders have advantages over existing solutions with their small size (mm x mm), zero-power, high-accuracy, and kilohertz update rates. Commercial applications such as human machine interfaces, virtual training environments, security, inventory control, computer gaming, and biomedical research exist. A brief review of existing tracking technologies including a discussion of how their shortcomings are overcome by this system is included. Surface acoustic wave (SAW) device design and modeling is covered with particular attention paid to implementation of passive transponders. A method under development to fabricate SAW devices with features as small as 300nm is then covered in detail. The electronic design of the radar chirp transmitter and receiver are covered along with the design and implementation of the test electronics. Results from experiments conducted to characterize device performance are given.
by Jason Michael LaPenta.
S.M.
Kondrath, Andrew Stephen. "Frequency Modulated Continuous Wave Radar and Video Fusion for Simultaneous Localization and Mapping". Wright State University / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=wright1347715085.
Pełny tekst źródłaCheung, Sai-Kit. "The study of weak localization effects on wave dynamics in mesoscopic media in the diffusive regime and at the localization transition /". View abstract or full-text, 2006. http://library.ust.hk/cgi/db/thesis.pl?PHYS%202006%20CHEUNG.
Pełny tekst źródłaEvers, Martin [Verfasser]. "Two antagonizing aspects of spin transport : spin-wave localization and spin superfluidity / Martin Evers". Konstanz : KOPS Universität Konstanz, 2019. http://d-nb.info/1230323309/34.
Pełny tekst źródłaHanley, Thomas Harry. "On the exploitation of mode localization in surface acoustic wave MEMS for sensing applications". Thesis, University of Newcastle upon Tyne, 2017. http://hdl.handle.net/10443/3711.
Pełny tekst źródłaPark, Won Hyun, i Won Hyun Park. "Acoustic Source Localization in an Anisotropic Plate Without Knowing its Material Properties". Diss., The University of Arizona, 2016. http://hdl.handle.net/10150/622963.
Pełny tekst źródłaChen, Xin. "Load-enhanced lamb wave methods for the in situ detection, localization and characterization of damage". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54859.
Pełny tekst źródłaSamarawickrama, Mahendra. "Acceleration Techniques for Sparse Recovery Based Plane-wave Decomposition of a Sound Field". Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17302.
Pełny tekst źródłaChan, Man Leong. "Optimization of electromagnetic follow up observations and localization of gravitational wave signals from compact binary coalescences". Thesis, University of Glasgow, 2018. http://theses.gla.ac.uk/31007/.
Pełny tekst źródłaGhatak, Gourab. "Millimeter wave multi-RAT small cells for heterogeneous mobile services : performance analysis and optimization". Thesis, Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT010/document.
Pełny tekst źródłaFuture wireless applications anticipate an explosion in the plethora of use-cases and services, which cannot be sustained by incremental improvements on the existing communication schemes. For this, two research directions are particularly attractive: network densification using small cells and millimeter wave (mm-wave) wave communications. In this thesis, we model and evaluate cellular networks consisting of multi-radio access technique (RAT) mm-wave small cells deployed on top of the legacy macro-architecture. First, we mathematically model a homogeneous deployment of multi-RAT small cells and characterize the user and network performance in terms of signal to interference plus noise ratio (SINR) coverage probability, downlink throughput, and the cell overloading probability. Then, we study users association to different tiers and optimal selection of different RATs, so as to optimize these performance metrics. Generally, cellular network models that assume homogeneous deployments of small cells fail to take into account the nuances of urban blockage characteristics. To address this, we model the small cell locations along the roads of a city, and subsequently, we take into consideration the signal blockages due to buildings or moving vehicles on the roads. In this network, we assume that the operator supports three types of services v.i.z., ultra-reliable low-latency communications (URLLC), massive machine-type communications (mMTC), and enhanced mobile broadband (eMBB) with different requirements. Consequently, we study the optimal RAT selection for these services with varying vehicular blockages. Finally, based on the on-road deployment model of mm-wave small cells, we study a network designed to support positioning and data services simultaneously. We characterize the positioning accuracy based on the localization bounds and then study optimal resource partitioning and beamwidth selection strategies to address varied positioning and data-rate requirements
Khames, Imene. "Nonlinear network wave equations : periodic solutions and graph characterizations". Thesis, Normandie, 2018. http://www.theses.fr/2018NORMIR04/document.
Pełny tekst źródłaIn this thesis, we study the discrete nonlinear wave equations in arbitrary finite networks. This is a general model, where the usual continuum Laplacian is replaced by the graph Laplacian. We consider such a wave equation with a cubic on-site nonlinearity which is the discrete φ4 model, describing a mechanical network of coupled nonlinear oscillators or an electrical network where the components are diodes or Josephson junctions. The linear graph wave equation is well understood in terms of normal modes, these are periodic solutions associated to the eigenvectors of the graph Laplacian. Our first goal is to investigate the continuation of normal modes in the nonlinear regime and the modes coupling in the presence of nonlinearity. By inspecting the normal modes of the graph Laplacian, we identify which ones can be extended into nonlinear periodic orbits. They are normal modes whose Laplacian eigenvectors are composed uniquely of {1}, {-1,+1} or {-1,0,+1}. We perform a systematic linear stability (Floquet) analysis of these orbits and show the modes coupling when the orbit is unstable. Then, we characterize all graphs for which there are eigenvectors of the graph Laplacian having all their components in {-1,+1} or {-1,0,+1}, using graph spectral theory. In the second part, we investigate periodic solutions that are spatially localized. Assuming a large amplitude localized initial condition on one node of the graph, we approximate its evolution by the Duffing equation. The rest of the network satisfies a linear system forced by the excited node. This approximation is validated by reducing the discrete φ4 equation to the graph nonlinear Schrödinger equation and by Fourier analysis. The results of this thesis relate nonlinear dynamics to graph spectral theory
Blomqvist, Anneli. "Millimeter Wave Radar as Navigation Sensor on Robotic Vacuum Cleaner". Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-288146.
Pełny tekst źródłaHar radar med millimetervågor förutsättningar att vara navigationsutrustning för en robotdammsugare i ett hem? Electrolux robotdammsugare använder för närvarande en ljussensor för att navigera genom hemmet medan den städar. Nyligen släppte Texas Instruments en ny radarsensor med vågor i frekvensområdet 60-64 GHz. Denna studie syftar till att svara om radarsensorn är användbar för inomhusnavigering. Studien testar sensorn med avseende på noggrannhet och upplösning av vinklar och avstånd i områden som är relevanta för inomhusnavigering. Den testar om olika föremål tillverkade av plast, tyg, papper, metall och trä kan detekteras av sensorn. Slutligen testas vad sensorn kan se om den rör sig medan den mäter. Radarsensorn kan positionera roboten, men hinderdetektering omkring roboten är begränsad. För det mesta ligger sensorns absoluta noggrannhet inom 3° för vinklar och omkring 1dm för avstånd över 0,5 m. Upplösningen för en förflyttning av ett objekt är 1° respektive 5 cm, och två objekt måste placeras minst 14° eller 15 cm ifrån varandra för att båda kunna upptäckas. Kommande utmaningar är att ta bort antennstörningar som ger sämre reflektioner inom 0,5 meter och ta reda på det bästa sättet att förflytta sensorn för att förbättra upplösningen.
Ghatak, Gourab. "Millimeter wave multi-RAT small cells for heterogeneous mobile services : performance analysis and optimization". Electronic Thesis or Diss., Université Paris-Saclay (ComUE), 2019. http://www.theses.fr/2019SACLT010.
Pełny tekst źródłaFuture wireless applications anticipate an explosion in the plethora of use-cases and services, which cannot be sustained by incremental improvements on the existing communication schemes. For this, two research directions are particularly attractive: network densification using small cells and millimeter wave (mm-wave) wave communications. In this thesis, we model and evaluate cellular networks consisting of multi-radio access technique (RAT) mm-wave small cells deployed on top of the legacy macro-architecture. First, we mathematically model a homogeneous deployment of multi-RAT small cells and characterize the user and network performance in terms of signal to interference plus noise ratio (SINR) coverage probability, downlink throughput, and the cell overloading probability. Then, we study users association to different tiers and optimal selection of different RATs, so as to optimize these performance metrics. Generally, cellular network models that assume homogeneous deployments of small cells fail to take into account the nuances of urban blockage characteristics. To address this, we model the small cell locations along the roads of a city, and subsequently, we take into consideration the signal blockages due to buildings or moving vehicles on the roads. In this network, we assume that the operator supports three types of services v.i.z., ultra-reliable low-latency communications (URLLC), massive machine-type communications (mMTC), and enhanced mobile broadband (eMBB) with different requirements. Consequently, we study the optimal RAT selection for these services with varying vehicular blockages. Finally, based on the on-road deployment model of mm-wave small cells, we study a network designed to support positioning and data services simultaneously. We characterize the positioning accuracy based on the localization bounds and then study optimal resource partitioning and beamwidth selection strategies to address varied positioning and data-rate requirements
Kiorpelidis, Ioannis-Markos. "Wave phenomena in one-dimensional space or time varying media". Electronic Thesis or Diss., Le Mans, 2023. https://cyberdoc-int.univ-lemans.fr/Theses/2023/2023LEMA1032.pdf.
Pełny tekst źródłaThe interaction of waves with media possessing spatial or/and temporal fluctuations leads tointeresting phenomenology. Within this framework, in the present thesis four wave phenomena arestudied: two occurring in spatially-varying media and two in time-varying media. We begin byexploring wave scattering by a finite spatially-periodic setup that is subject to perturbation. Ourfocus is on perfect transmission resonances (PTRs) and we develop a method for preserving themunder asymmetric perturbations. The performed analysis reveals a pairwise connection betweenPTRs of a spatially-periodic scattering setup with mirror symmetric cells. In the same contextof spatially varying media, we compute the localization length of the topological edge modes thatare supported in a mechanical mass-spring chain possessing random fluctuations of its stiffnessparameters. In the presence of strong chiral disorder the localization length diverges, implying atopological phase transition that is induced purely by disorder. As a next step we consider thecase where the couplings of the mechanical mass-spring chain vary with time in a deterministicway. Then this time-varying system can serve as a platform for transferring a topological edgemode. Going beyond the adiabatic limit, we design a protocol for the time-varying couplingsthat results in a fast and robust transfer and even more leads to amplification of the transferrededge mode. To shed light into the phenomenon of amplification in a time-varying platform, weexplore the propagation of a wave in a medium with time-periodic refractive index and with wavedynamics governed by the Mathieu equation. The wave exhibits transient amplification due to thenon normal nature of the propagator matrix and we provide numerical evidence that the globalamplifying features are provided merely by the monodromy matrix
Obeidat, Huthaifa A. N. "Investigation of Indoor Propagation Algorithms for Localization Purposes: Simulation and Measurements of Indoor Propagation Algorithms for Localization Applications using Wall Correction Factors, Local Mean Power Estimation and Ray Tracing Validations". Thesis, University of Bradford, 2018. http://hdl.handle.net/10454/17385.
Pełny tekst źródłaKim, Hyunki. "Spatial variability in soils stiffness and strength /". Diss., Available online, Georgia Institute of Technology, 2005, 2005. http://etd.gatech.edu/theses/available/etd-07132005-194445/.
Pełny tekst źródłaMayne, Paul, Committee Member ; Frost, David, Committee Member ; Santamarina, Carlos, Committee Chair ; Rix, Glenn, Committee Member ; Ruppel, Carolyn, Committee Member.
El, Khatib Muammar. "Characterization of metallic and insulating properties of low-dimensional systems". Thesis, Toulouse 3, 2015. http://www.theses.fr/2015TOU30198/document.
Pełny tekst źródłaI carried out a theoretical study to characterize metallic and insulating properties of low-dimensional systems using wave function methods. Low-dimensional systems are particularly important because they allow an understanding that can be extrapolated to higher dimensional systems. We have employed a new tool based on the theory of conductivity of Kohn that we have named: total position-spread tensor (TPS). The TPS is defined as the second moment cumulant of the total position operator: ? = - 2 . The tensor divided by the number of electrons diverges when the wave function is delocalized (high fluctuation of electrons' positions), and it takes finite values for localized ones. In this way, the electrical conductivity is related to the proper delocalization of the wave function. In addition, the tensor can be divided in spin-summed (SS-TPS) and spin-partitioned tensors (SP-TPS). The latter one becomes a powerful tool to the study of strongly correlated systems. In this dissertation, we started to investigate at full configuration interaction (FCI) level diatomic molecules showing different types of bond. The TPS presented a marked maximum before the bond was broken and in the asymptotic limit one recovers the TPS values of isolated atoms (size consistency). For the case of diatomic systems showing avoided-crossing electronic states, the TPS diverges evidencing the high delocalization of the wave function. Therefore, the SS-TPS is capable of monitoring and characterizing molecular wave functions. We considered mixed-valence systems that are often distinguished by a double-well potential energy surface presenting an avoided-crossing. Thus, such a configuration possesses a strongly multireference nature involving at least two states of the same symmetry. Two different systems were investigated: i) two weakly interacting hydrogen dimers that were investigated at Full CI level, and ii) a spiro like molecule where the TPS tensor was evaluated in a CAS-SCF state-averaged wave function using our implementation of the SS- TPS formalism in MOLPRO. We found that the tensor's component in the direction of the electron transfer (ET) shows a marked maximum in the avoided-crossing region, evidencing the presence of a high electron mobility. The formalisms of the SS- and SP-TPS was applied to one dimensional systems composed by three types of half-filled hydrogen chains: i) equally-spaced chains, ii) fixed-bond dimerized chains, and iii) homothetic dimerized chains. Both the SS- and SP-TPS showed different signatures associated to the three types of systems. Equally-spaced chains have metallic wave functions and a high spin delocalization in the strongly correlated regime. In contrast, fixed-bond dimerized chains have an insulating character and a restricted spin delocalization. Finally, homothetic dimerized chains dissociate very quickly which renders them in the insulating state but with a high spin delocalization. We also studied half-filled chains by using the Hubbard and the Heisenberg Hamiltonians. On the one hand, we were able to depict the response of the SS- and SP-TPS by varying the ratio between the hopping and electron-electron repulsion (-t/U parameter) of topological connected sites. On the other hand, the ferromagnetic and anti-ferromagnetic character of the wave functions were evaluated by varying the coupling constant (J) in the strongly correlated systems. A theoretical study of closed polyacenes (PAH) structures was performed at CAS-SCF and NEVPT2 level. Our methodology for choosing the active space using the Hückel Hamiltonian was able to characterize the ground state of the systems that indeed fulfilled the Ovchinnikov rule. Finally, we applied the SS-TPS to understand the nature of the wave functions of these PAHs
Denechaud, Vincent. "Vers une étude spectroscopique de la transition d'Anderson". Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLO002/document.
Pełny tekst źródłaThis manuscript summarizes the work of a thesis on Anderson's localization and transport of ultra-cold matter waves in disordered media. This is an experimental work aiming to study the Anderson transition separating the energy states of a quantum particle placed in a disordered potential into two phases: localized states and diffusive states.First, we will recall some fundamental concepts about wave localization and how such phenomenon is linked with some interference effects. Then, we will give a global description of the experimental set-up allowing to prepare the ultra-cold atomic samples used as a source of quantum matter waves, and to generate the speckle field used as disordered potential for the atoms.At the end of this introductory work, the concepts of localization introduced previously will be applied to the transport of cold atoms in a speckle field. A brief state of the art of cold-atom experiments dealing with the Anderson transition will allow us to set the limits of these works in terms of energy control on the atomic states. These limitations will then motivate the implementation of a new experimental "spectroscopic" method allowing a complete control of the energy of the atoms placed in disorder.The concept of spectral function will then be presented as a fundamental tool for characterizing energy states and for calibrating the energy reliability of the spectroscopic method. Finally, the experimental results on the measurement of spectral functions by this new spectroscopic method will show that it would be indeed possible to study the Anderson transition with a much higher energy resolution than the previous experiments
Amiot, Nicolas. "Design of simulation platform joigning site specific radio propagation and human mobility for localization applications". Phd thesis, Université Rennes 1, 2013. http://tel.archives-ouvertes.fr/tel-00971809.
Pełny tekst źródłaHildebrand, William Kurt. "Ultrasonic waves in strongly scattering disordered media: understanding complex systems through statistics and correlations of multiply scattered acoustic and elastic waves". American Physical Society, 2014. http://hdl.handle.net/1993/30843.
Pełny tekst źródłaOctober 2015
Rodrigues, Cunha Leandro. "Robust bandgaps for vibration control in periodic structures". Thesis, Bourgogne Franche-Comté, 2017. http://www.theses.fr/2017UBFCD060.
Pełny tekst źródłaIn this thesis, a simple methodology to find robust bandgaps is presented. Four different periodic structures are used as numerical examples for infinite and finite models. The first two are related to attenuation zones created for longitudinal waves using spring-mass and stepped rod unit cells. The Transfer Matrix method is used to model the unit cell. With this method, it is possible to obtain the frequency responses, using a spectral method, and dispersion constants, solving an eigenvalue prob-lem. The most influential physical and geometrical parameters are determined by performing partial derivative and finite difference sensitivity analysis through an infinite model. Therein, for the second example, the cross-section area of half-cell is considered as a stochastic variable represented by a probability density function with specific deviation properties for a probabilistic analysis. The third example concerns the bandgaps for flexural waves using stepped beams unit cells. For this case, the classical Transfer Matrix method cannot be used to obtain finite structures response in low frequency because of the presence of ill-conditioned matrices. Therefore, a recursive method termed Translation Matrix, which avoid matrix multiplication, is used and the corresponding probabilistic analysis is per-formed using the half-cell thickness as a random variable. An experimental analysis is also performed for this case, but considering half-cell length as uncertain. The last example is a periodic truss that is considered with and without smart components. The unit cell of this lattice structure can present pas-sive and active members. As long as the type of unit cell is more complex, the finite element method is used. However, this kind of structure does not have impedance mismatches strong enough to open bandgaps although the presence of repetitive substructures. In virtue of this, eight scenarios are inves-tigated considering the introduction of concentrated mass on joints and piezoelectric actuators in reso-nant shunt circuit which are considered as stochastic for specific cases. For each structure model, a Monte Carlo Simulation with Latin Hypercube sampling is carried out, the distinctions between the corresponding uncertain attenuation zones for finite and infinite models are exposed and the relation with localized modes is clarified. These results lead to conclude that the finite models present a larger stop zone considering stochastic parameters than infinite models. In other words, the uncertainties be-tween neighbors’ cells compensate each other and the finite structures is naturally more robust. Final-ly, the effect of increasing the uncertainty level, by varying a stochastic coefficient, is analyzed and the concept of robust band gap is presented
Prat, Tony. "Localisation d'Anderson avec des atomes froids : dynamique dans le désordre et perspectives avec des modèles chaotiques". Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066232/document.
Pełny tekst źródłaThis thesis theoretically investigates several effects related to Anderson localization, focusing on the context of disordered and chaotic cold-atomic systems. In cold-atomic systems, optical speckle patterns are often used to create the disorder. The resulting potentials felt by the atoms differ from Gaussian random potentials, commonly assumed in the description of condensed-matter systems. In the first part of the thesis, we discuss their specificities, with an emphasis on the spectral properties. Atom-optics experiments offer interesting possibilities, such as the possibility to directly probe the atoms inside the disordered potential. In view of these possibilities, we consider in the second part of the thesis the spreading of matter wave packets initially launched with a non-zero velocity. We find that after an initial ballistic motion, the packet center-of-mass experiences a retroreflection and slowly returns to its initial position, mimicking a boomerang. Atom-atom interactions are then introduced in a third part. We consider dilute condensed bosonic gases, and treat the interactions at the mean-field (Gross-Pitaevskii) level. Various situations are studied numerically, in particular the quantum boomerang scenario, and the dynamical spreading both in momentum and energy of matter waves prepared as plane waves. In the last part, we show that chaotic models offer interesting prospects for the study of Anderson localization. On the one hand, we present strong evidences in favor of a spinless kicked rotor in the sympletic ensemble. On the other hand, a second look at a commonly studied quasi-periodically modulated kicked rotor reveals intriguing results
Koirala, Remun. "Fonctions conjointes de localisation et de communication dans les réseaux 5G en bandes millimétriques". Thesis, Rennes 1, 2020. http://www.theses.fr/2020REN1S005.
Pełny tekst źródłaIn this thesis, we investigate different facets of localization and communication services motivated by the symbiosis between them in the millimeter wave (mm-Wave) context for the fifth generation (5G) of wireless communications. Our aim is twofold: first, show that this duality is mutually beneficial to both services, and second, aim towards a co-existence to capture these benefits in order to bring forth mm-Wave as a strong contender for 5G. First, we look into how beamforming, an integral part of mm-Wave communications, can aid in improving the localization performance. After characterizing the localization performance in terms of Cramer-Rao lower bound (CRLB), we show that with optimized beamforming, the estimation of localization variables (delay, angle of departure (AoD) and angle of arrival (AoA)) improves. Then we consider the problem of co-existence of the two services together in the same system while sharing time and frequency resources. We study the non-trivial trade-off between the performances of the two services during this resource budgeting. Then, relying on this trade-off, we design an optimal resource allocation scheme while also optimizing the beamwidth in order to ascertain high performance in terms of both localization and communication. In the same context, we also look into different applications of this improved location information namely initial access, channel estimation and simultaneous localization and communication (SLAM). We show that the related performances improve in terms of quality, latency and/or complexity in comparison to the conventional methods
Costa, Alex Emanuel Barros. "Deslocalização de ondas acústicas em sistemas unidimensionais não periódicos". Universidade Federal de Alagoas, 2011. http://www.repositorio.ufal.br/handle/riufal/1663.
Pełny tekst źródłaCoordenação de Aperfeiçoamento de Pessoal de Nível Superior
Nesta dissertação de mestrado estudamos numericamente a propagação de ondas acústicas em meios não periódicos unidimensionais. Nós nos concentramos em dois tipos de meios: (1) com distribuição da elasticidade possuindo correlação de longo alcance e (2) com distribuição aperiódica pseudo-aleatória. No primeiro caso, a elasticidade da distribuição aleatória é assumida ter um espectro de potência S(k)~1/kª. Usando o método de matriz de transferência resolvemos a versão discreta da equação da onda escalar e calculamos o comprimento de localização. Além disso, aplicamos o método de diferença infinita de segunda ordem para as variáveis temporal e espacial e estudamos a natureza das ondas que se propagem na cadeia. Nossos dados numéricos indicam a presença de ondas acústicas estendidas para alto grau de correlação. Em contraste com correlação local, demonstramos numericamente que correlações de livre-escala promovem uma fase estável com ondas acústicas livres no limite termodinâmico. No outro caso, a distribuição das constantes elásticas foram geradas usando uma função senoidal cuja faze varia como uma lei de potência, ϕ α nv , onde n rotula as posições ao longo da rede. Ao considerar novamente uma versão unidimensional discretizada da equação de onda e uma reformulação da matriz recursiva nós calculamos o comprimento de localização dentro da faixa de frequências permitidas. Nossos dados indicam a presença de ondas acústicas propagantes com frequência diferente de zero para um suficiente grau de aperiodicidade.
Rüdiger, Benz. "Localization of notches with lamb waves". Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/21510.
Pełny tekst źródłaRazo, López Luis Alberto. "Localisation des ondes électromagnétiques au-delà d'Anderson : rôle des corrélations, des symétries et de la topologie". Electronic Thesis or Diss., Université Côte d'Azur, 2024. http://www.theses.fr/2024COAZ5013.
Pełny tekst źródłaIn a broad sense, the term wave localization refers to a phenomenon where waves are spatially confined in small regions of the space without any bounding material barriers.In this Thesis, we investigate (analytically, numerically and experimentally) different physical collective mechanisms to spatially localize, and therefore, to control electromagnetic waves. Specifically, we focus on the role of uncorrelated and correlated potentials, as well as of topological effects to achieve wave confinement. Analytical and numerical studies are accomplished in the framework of a recent approach in the modeling of Anderson localization called localization landscape theory. On the other hand, experiments are performed using a microwave platform composed by small dielectric cylinders placed inside a cavity made of two metallic plates. The cavity implements a propagative wave system, where we can efficiently control the local permittivity by means of the cylinders acting as scatterers, or as an analogic tight-binding system, where, in this case, the dielectric cylinders play the role of resonators.First, we extend the scope of the localization landscape approach to a wide class of one and two dimensional tight-binding systems in the presence of uncorrelated disorder, where localized eigenfunctions appear in both band-edges. We demonstrate how the landscape theory is able to predict accurately not only the locations, but also the energies of localized eigenfunctions in the low- and high-energy regimes. Later, by using our experimental cavity as a propagative system, we perform microwave transport experiments in two dimensional planar arrays. Experiments are carried out on a disordered lattice and on an aperiodic Vogel spiral from where we characterize the electromagnetic modal structures in real space. Our results reveals that aperiodic systems can carry a rich variety of long-lived modes—with Gaussian, exponential, and power law spatial decays—which are able to survive even in a three-dimensional environment. This is supported by different transport quantities such as the density of states, the characteristic decay time, and the Thouless conductance that are also experimentally accessible. On the contrary, we show that the eigenstates in traditional disordered media are always limited to exponential radial decays with leaking features beyond two-dimensions.Finally, we use the experimental tight-binding configuration to investigate the propagation of topological helical states. Particularly, we experimentally analyze a set of honeycomb-like structures built using a triangular lattice with an hexagonal unit cell, which are characterized by the Z_2 topological invariant. By recovering the modal structure in real space and the density of states, our results reveal the possibility to open a topological gap, dwelt by edge states that lives in the border of the structure.We demonstrate the unidirectional counterpropagative features of such helical edge states.Taken together, our results demonstrate that it is possible to model, control and localize electromagnetic waves not only within, but beyond Anderson's conception. Thanks to the crossroads we have taken, we have mapped out an itinerary that brings us closer to the main avenue leading perhaps to Anderson localization of three dimensional electromagnetic waves
Agred, Kahina. "Localisation automatique des aciers et caractérisation de la teneur en eau du béton armé par radar double-offset à grand rendement". Thesis, Toulouse 3, 2017. http://www.theses.fr/2017TOU30194/document.
Pełny tekst źródłaSince budgets for the maintenance and repair of built heritage structures are very high, it is essential to implement reliable techniques for monitoring and diagnosis of structures to reduce these costs. There are many non-destructive testing (NDT) methods employing different technologies which are more or less expensive. The NDT methods allow the determination of the properties of the material giving also information about the condition of the structure, and the detection of inclusions or defects in the concrete. These techniques are known for their fast implementation and their high performance in-situ, but also by their non-intrusive nature, which makes it possible to limit the number of samples for destructive assessment. This makes them relevant for the monitoring and inspection of built heritage, since they can provide information related to the condition of a structure without any damage. In a reinforced concrete structure, the concrete cover is the most prone to multiple aggressions. The majority of the chemical reactions which cause the degradation of the structure occur in this layer, since with the presence of water this coating is considered as the penetration, transfer and fixing zone of aggressive agents present in the environment of the structure, thus enhancing for example the corrosion of the reinforcements. The water content of concrete is considered as a very important factor in the diagnosis of reinforced concrete structures, since it conditions the development of most pathologies related to structural degradation, thus affecting the durability of concrete. The precise location of the reinforcement in the construction is also an essential element for the diagnosis, but also to check the conformity of the constructive dispositions with the execution plans. In this research, we use GPR technology for the geometrical and physical characterization of reinforced concrete elements, through the development of an automatic algorithm, fast and without pre-requisites. The objectives of this study are to locate the rebars of the first reinforcing layer in the plane and depth and to determine the propagation velocity of the electromagnetic waves in the coating layer to estimate the water content of concrete
Laptyeva, Tetyana V. "Nonlinear waves in random lattices: localization and spreading". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-107881.
Pełny tekst źródłaGrataloup, Géraldine Léonie 1979. "Localization of nonlinear water waves over a random bottom". Thesis, Massachusetts Institute of Technology, 2003. http://hdl.handle.net/1721.1/16918.
Pełny tekst źródłaIncludes bibliographical references (p. 87-90).
This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
by Géraldine Léonie Grataloup.
S.M.
Larcher, Marco. "Localization and spreading of matter waves in disordered potentials". Doctoral thesis, Università degli studi di Trento, 2013. https://hdl.handle.net/11572/367883.
Pełny tekst źródłaLarcher, Marco. "Localization and spreading of matter waves in disordered potentials". Doctoral thesis, University of Trento, 2013. http://eprints-phd.biblio.unitn.it/889/2/Thesis_Larcher.pdf.
Pełny tekst źródłaPodbielski, Jan. "Localization, coupling and interference of spin waves in ferromagnetic nanostructures". München Verl. Dr. Hut, 2008. http://d-nb.info/988228904/04.
Pełny tekst źródłaLyu, Pengfei. "Numerical and Experimental Indoor Channel Analysis for LOS-NLOS Identification at 60 GHz". Electronic Thesis or Diss., Sorbonne université, 2020. http://www.theses.fr/2020SORUS186.
Pełny tekst źródłaWith the emergence of connected objects, potential applications requiring indoor location or location continuity have reappeared and have been the subject of numerous studies and researches for several years now. The IEEE 802.11ad standard, operating around 60 GHz, is a potential candidate to solve the localization problem while allowing high data rate communication. However, this promising standard is particularly subject to blockage of direct waves. Indeed, no calculation of spatial coordinates can be undertaken if the processed signals do not come from a line of sight propagation (LOS). This limitation consequently induces a new problem which consists in ensuring, in the signals of interest, the presence of the LOS contribution. It also comes down to identifying the NLOS components brought by the multipath phenomenon. NLOS path identification uses beam-learning methods that provide access to the angular spectrum of a channel. A first classification, by clusters, is carried out, then a statistical analysis using the fourth standardized moment, is conducted on each cluster. The use of this "kurtosis" signature allows a second classification discriminating clusters induced by LOS contributions from those induced by NLOS contributions
Torrents, Verdaguer Genís. "New insights into holography from supersymmetric localization". Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/398760.
Pełny tekst źródłaAquesta tesi estudia les lliçons que hom pot extreure, des del punt de vista de la dualitat hologràfica, de l'anomenada localització supersimètrica. La conjunció d'aquests dos formalismes ha estat utilitzada anteriorment per verificar els resultats del primer, però aquesta tesi va un pas més enllà i qüestiona fins a quin punt els resultats exactes oferts per la localització poden ser útils per extendre l'aplicabilitat de l'holografia gravitatòria. L'anàlisi d'aquests resultats en diferents règims posa de relleu diversos aspectes d'interès. Una primera observació és que la dependència funcional exacta que hom pot llegir dels resultats de la localització ofereixen, quan són utilitzats amb cura, una guia per estendre les prediccions holgràfiques des del seu règim de validesa a un rang de gauge finit mitjançant la qual es pot obtenir resultats plausibles. Complementàriament, l'estudi d'aquesta dependència paramètrica per teories maximalment super-simètriques amb grups de Lie clàssics presenta dos patrons suggerents: d'una banda, el desenvolupa-ment de 't Hooft té, almenys per càrregues en representació fonamental, una estructura subjacent que relaciona els sectors amb diferent nombre d'inversions topològiques entre ells. De l'altra, l'estructura dels models de matrius obtinguts en localitzar pot ésser interpretada en termes d'una mecànica quàntica de fermions, que encaixa amb l'estructura dels "universos de bombolles" de Lin, Lunin i Maldacena al límit de 't Hooft, però que manté la seva forma a qualsevol rang finit. Per últim, es compara resultats de localització entre ells en un marc de teories més generals, en què algunes admeten dual semiclàssic i d'altres no és d'esperar que ho facin. Les prediccions supersimètriques en aquest cas presenten diferències qualitatives que permeten distingir aquests dos grups de teories, suggerint una possible connexió entre la codificació de l'estructura gravitatòria a la teoria de camps i el model de matrius que s'obté en localitzar que complementa altres indicis en el mateix sentit obtinguts a la literatura. En definitiva, doncs, es posa de manifest en aquesta tesi que, tot i haver restringit l'anàlisi a sectors i observables específics, els resultats obtinguts per mitjà de la localització supersimètrica ofereixen una rica gamma de suggeriments sobre l'estructura hologràfica.
Glaister, A. J., Amri R. Al i David P. Spicer. "Talent management: managerial sense making in the wake of Omanization". Routledge, 2018. http://hdl.handle.net/10454/17818.
Pełny tekst źródłaWe examine how managers in Oman make sense of localization policies (Omanization) through their use of talent management (TM). Through an institutional logics (IL) lens, it is possible to examine how organizations confront institutional complexity and understand the interplay between state, market and societal logics. The paper analyses twenty-six interviews with managers in the Petroleum and Banking sector and is the first to examine TM within the context of Omanization using a layered, IL perspective. The paper finds that punitive state logics encourage organizations to focus on the societal wellbeing of their TM measures and inspires a sense of corporate social responsibility. Yet, the market logic dictates a stratified and differentiated approach that manages impressions of inclusivity while safeguarding organizational interests.
Draper, Brandon J. "Long-range outdoor monocular localization with active features for ship air wake measurement". Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/122504.
Pełny tekst źródłaCataloged from PDF version of thesis.
Includes bibliographical references (pages 85-87).
Monocular pose estimation is a well-studied aspect of computer vision with a wide array of applications, including camera calibration, autonomous navigation, object pose tracking, augmented reality, and numerous other areas. However, some unexplored areas of camera pose estimation remain academically interesting. This thesis provides a detailed description of the system hardware and software that permits operation in one application area in particular: long-range, precise monocular pose estimation in feature-starved environments. The novel approach to pose extraction uses special hardware, including active LED features and a bandpass-interference optical filter, to significantly simplify the image processing step of the Perspective-n-Point (PnP) problem. The PnP problem describes the calculation of pose from n extracted image points corresponding to n known 3D world points. The proposed application method operates in tandem with a tethered unmanned aerial vehicle (UAV) and mobile ground control station (GCS). The integrated localization and flight system serves as a platform for future U.S. Navy air flow research. Indoor tests at the RAVEN flight space of MIT's Aerospace Controls Lab and outdoor tests at a grass strip runway demonstrate the system's efficacy in providing an accurate and precise pose estimate of the UAV relative to the mobile GCS.
"Sources of funding for the project and my educational pursuits at MIT: Creare, LLC., the Small Business Technology Transfer (STTR), and the Office of Naval Research"--Page 5
by Brandon J. Draper.
S.M.
S.M. Massachusetts Institute of Technology, Department of Aeronautics and Astronautics
Kuehnert, Julian. "Simulation of High Frequency Seismic Waves generated by Rockfalls on Real Topography". Thesis, Université de Paris (2019-....), 2019. https://theses.md.univ-paris-diderot.fr/KUEHNERT_Julian_va2.pdf.
Pełny tekst źródłaRockfall hazard has to be evaluated and monitored in order to prevent loss of life and infrastructure. In this regard it is important to create event catalogs and understand rockfall dynamics. Seismic waves can help for this purpose as they carry valuable information of the event. They are generated when rockfalls impact the ground and can be used to detect, classify and locate events. Beyond that, rockfall properties such as their volume and their dynamic behavior can be inferred. Yet, high frequency seismic signals (>1Hz) are poorly understood. This is because they are associated to complex seismic sources which are spatially distributed and can rapidly vary over time. On top of this, high frequency seismic waves are prone to be scattered and diffracted due to interactions with soil heterogeneities or surface topography. This thesis takes an important step forward to enhance understanding of high frequency rockfall seismic signals by simulating seismic wave propagation on domains with realistic velocity profiles and 3D surface topographies using the Spectral Element Method (SEM). The influence of the topography on the seismic wave field is investigated. It is found that topography induced amplification is substantially different between deep sources and sources located at the surface. This is because surface waves generated by shallow sources are exposed to constant scattering and diffraction when traveling along the surface. The energy decay along the surface is investigated for different velocity models and equations are derived to back-calculate the total seismic energy radiated by the source. This is of interest as the rockfall seismic energy is related to the rockfall volume. In order to account for topography effects, a correction factor is proposed which can be introduced in the energy calculation. Observed seismic signals generated by rockfall at Dolomieu crater on Piton de la Fournaise volcano, La Réunion, are analyzed. Synthetic seismograms are used to identify and interpret observed signals generated by single impacts. The influence of topography on the waveforms is demonstrated and the sensitivity on source location as well as source direction is evaluated. Signal characteristics such as amplitudes and frequency content are explained based on Hertz contact theory. Additionally, inter-station spectral ratios computed from rockfall seismic signals are shown to be characteristic of the source position. Comparison with simulated spectral ratios suggest that they are dominated by the propagation along the topography rather than the mechanism of the source. Based on these findings, a method is proposed for the localization of rockfalls using simulated inter-station energy ratios. The method is applied to localize rockfalls at Dolomieu crater. The implementation of the method involves a sliding time window which allows a straightforward application on continuous seismic signals. The potential of the method to monitor rockfall activity in real-time is emphasized
Harley, Joel B. "Data-Driven, Sparsity-Based Matched Field Processing for Structural Health Monitoring". Research Showcase @ CMU, 2014. http://repository.cmu.edu/dissertations/392.
Pełny tekst źródłaKotol, Martin. "Neuronové modelování elektromegnetických polí uvnitř automobilů". Doctoral thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2018. http://www.nusl.cz/ntk/nusl-390291.
Pełny tekst źródłaRayanov, Kristian. "Coherence of Matter and Light Waves in Localizing Media". Master's thesis, Universitätsbibliothek Chemnitz, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-qucosa-88015.
Pełny tekst źródłaDie Phänomene von Kohärenz und Lokalisierung haben sich in den letzten Jahrzehnten zum Schwerpunkt zahlreicher Forschungsinteressen entwickelt. Erst kürzlich wurden theoretische Vorhersagen von Lokalisierung in verschiedensten Experimenten in den Bereichen der Festkörperphysik und Optik bestätigt. In dieser Arbeit wird das häufig angewendete Modell der eindimensionalen diskreten nichtlinearen Schrödingergleichung betrachtet, welches die Untersuchung der Lokalisierung von linearen und nichtlinearen Wellen ermöglicht. Eine generelle Verbindung zwischen Kohärenz und Lokalisierung wird gezeigt, wonach lokalisierte Lösungen notwendigerweise kohärent sind. Die Auswirkungen eines Verlustes von Kohärenz werden numerisch durch Anwendung unterschiedlicher Methoden eines zufälligen Dephasierens untersucht. Ein permanentes Dephasieren führt stets zum Auftreten eines diffusiven Regimes, welches letztlich die Zerstörung von Lokalisierung bedingt. Nach einer endlichen Integrationszeit wird jedoch eine maximale Delokalisierung nur durch eine bestimmte Rate und Stärke des Dephasierens bewirkt, resultierend aus einem Wettstreit zwischen möglichst schneller Zerstörung des ursprünglichen Wellenpaketes auf der einen Seite und nicht zu starker Behinderung des Zerfließens auf der anderen. Wird das Dephasieren nach einer bestimmten Zeit abgeschaltet, so entspricht ein folglicher Verlust oder Zugewinn an Kohäarenz in einem linearen Wellenpaket direkt einem Verlust oder Zugewinn von Lokalisierung. Dabei treten im allgemeinen stabile teil-kohärente Wellenpakete auf. Im Gegensatz dazu ist Lokalisierung nichtlinearer Wellenpakete stets mit den Bemühungen verbunden, vollständige Kohärenz wiederherzustellen, zumindest für asymptotisch lange Zeiten. Auf mittleren Zeitskalen können jedoch verschiedene interessante teil-kohärente Strukturen beobachtet werden
Carrara, Matteo. "Fourier-based design of acoustic transducers". Diss., Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54925.
Pełny tekst źródłaSchulte, 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.
Pełny tekst źródłaIn 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
Stellin, Filippo. "Anderson localization in interacting quantum systems". Thesis, Université de Paris (2019-....), 2020. http://www.theses.fr/2020UNIP7004.
Pełny tekst źródłaIn this thesis we theoretically investigate the behaviour of quantum particles (electrons, atoms, photons, etc.) moving in a random medium and undergoing Anderson localization. For noninteractingparticles, the energy spectrum can possess one or more critical points, where the nature of the single-particle wavefunctions changes from extended to localized leading to a undergoes a metal-insulator phase transition, also known as Anderson transition.A fundamental question is whether and how Anderson transitions survive in interacting quantum systems. Here we study a minimal model of two particles moving in a disordered lattice and subject to short-range mutual interactions. By combining large-scale numerics with Green’s functions techniques, we show that two-particle Anderson transitions do occur in three dimensions and explore the phase diagram in the space of energy, disorder and interaction strength. The latter presents a rich structure, characterized by a doubly reentrant behavior, caused by the competition between scattering and bound states of the pair. We also show that previous claims of 2D Anderson transitions of the pair are essentially due to finite-size effects.A second problem that we address in this thesis is the occurrence of 2D metal-insulator transitions for a single particle in the presence of a spatially correlated potential and subject to spin-orbit interactions, described by Rashba-Dresselhaus couplings. We illustrate that, irrespective of the properties of the disorder, there is a regime where the critical energy depends linearly on the disorder strength. The slope and the intercept are studied in the vicinity of the spin-helix point, where the SU(2) symmetry is restored and the 2D metal-insulator transition disappears