Dissertations / Theses on the topic 'Scattering signal'
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Jussila, Adam P. "Simulating Pulsar Signal Scattering in the Interstellar Medium with Two Distinct Scattering Phenomena." Oberlin College Honors Theses / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=oberlin1528814998720461.
Full textYeo, Richard Fraser. "The three dimensional simulation of VLF signal scattering." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.286749.
Full textCall, John B. "Large-signal characterization and modeling of nonlinear devices using scattering parameters." Thesis, Virginia Tech, 2002. http://hdl.handle.net/10919/35548.
Full textMaster of Science
Hamilton, Shaun Ashley, and mikewood@deakin edu au. "A technique for improving the reception of scattering signal behind an obstacle." Deakin University. School of Sciences, 1991. http://tux.lib.deakin.edu.au./adt-VDU/public/adt-VDU20060726.151839.
Full textBowen, Stephen Gerard. "Forward scattering of a pulsed continuous wave signal through laminar and turbulent thermal plumes." Thesis, Springfield, Va. : Available from the National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA271210.
Full textThesis advisor(s): Catipovic, Josko. September 1993. Bibliography: p. 72-74. Also available online.
Alkhafaji, Nasr Nomas Hussein. "UHF and Microwave Phase-Modulated Scattering Array." PDXScholar, 2019. https://pdxscholar.library.pdx.edu/open_access_etds/4998.
Full textMillar, Alexander Paul. "Plasma diagnostic signal analysis : a Bayesian based genetic algorithm approach." Thesis, University of Glasgow, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.326472.
Full textDuffy, Christopher. "Stimulated Brillouin Scattering In Monomode Optical Fibres For Sensing And Signal Processing Applications." Thesis, Cranfield University, 1994. http://dspace.lib.cranfield.ac.uk/handle/1826/4550.
Full textRiley, Douglas J. "Single and multiple electromagnetic scattering by dielectric obstacles from a resonance perspective." Diss., Virginia Polytechnic Institute and State University, 1986. http://hdl.handle.net/10919/71273.
Full textPh. D.
Walsh, Norman J. "Bandwidth and signal-to-noise ratio enhancement of the NPS Transient Electromagnetic Scattering Laboratory." Thesis, Monterey, California. Naval Postgraduate School, 1989. http://hdl.handle.net/10945/25710.
Full textRobertson, Lain Elisabeth. "The fundamental role of spectral scattering in the ocean colour Phytoplankton Functional Type signal." Doctoral thesis, University of Cape Town, 2018. http://hdl.handle.net/11427/27856.
Full textKummer, Joseph W. "Signal processing methods to quantify scattering of angle-beam shear waves from through-holes in plates." Thesis, Georgia Institute of Technology, 2015. http://hdl.handle.net/1853/54411.
Full textCooper, Ian Philip. "Coherence as a Measure of Body-Wave Signal to Noise Ratio in the Northeastern United States and Southeastern Canada:." Thesis, Boston College, 2021. http://hdl.handle.net/2345/bc-ir:109210.
Full textDetermination of the source parameters of a local earthquake from full seismic waveforms requires seismograms with clear body-wave signals from the earthquake source. Coherence of the earthquake body-wave seismograms recorded at two different receivers can be used to estimate the signal-to-noise ratio (SNR) of the body-wave energy radiated by the source. In this study, the coherence of earthquake body waves recorded in the Northeastern United States and Southeastern Canada (NEUSSEC) is measured as a function of frequency, interstation distance, and ambient SNR, and then used as an estimate of body-wave SNR. Seismograms from the CN, IU, LD, N4, NE, TA, and US arrays were used to measure coherence between stations with a mean separation of 70 km. Seismograms from the Acton Littleton Seismic Array (ALSA) were used to measure coherence at 5 km mean station separation. Coherence is measured at frequencies between 0.05-10 Hz for Pn and Sn phases from NEUSSEC earthquakes with magnitudes (M) between 0.0 and 4.7 at epicentral distances between 180-1800 km as well as at frequencies between 0.05-10 Hz for the first arrivals of P and S waves from earthquakes M>6 at distances >2500 km. The teleseismic P waves display values of coherence greater than 0.9 out to interstation distances of 1500 km at frequencies <0.8 Hz, but as frequency increases, the interstation distance at which coherence falls below 0.9 decreases. Teleseismic S and regional Pn and Sn waves display coherence values around 0.5, suggesting the amplitudes of the body-waves are smaller than those of the noise, which likely is the result of converted and reflected or refracted P waves and/or smaller signal amplitudes. These coherence values are compared to the coherence values of ambient noise. For any two P, S, Pn or Sn waveforms recorded in the NEUSSEC at 3-5 Hz there is a 50% or greater chance of those two waveforms containing coherent energy that is not ambient noise; these frequencies are where this percent chance is greatest for all seismic phases. At frequencies between 3-5 Hz the effects of scattering are most pronounced on the coherence values of regional seismic phases, suggesting that most scattering in the crust of the NEUSSEC takes place at these frequencies. Teleseismic seismic phases do not include as much scattered energy as the regional seismic phases at 3-5 Hz, and must therefore encounter fewer scattering heterogeneities along their travel path than the regional seismic phases
Thesis (MS) — Boston College, 2021
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Earth and Environmental Sciences
Nguyen, Linh Trung. "Estimation and separation of linear frequency- modulated signals in wireless communications using time - frequency signal processing." Queensland University of Technology, 2004. http://eprints.qut.edu.au/15984/.
Full textVan, den Broeck Samuel. "Optique statistique appliquée à la granulométrie submicronique : simulation d'un signal gaussien lorentzien." Rouen, 1998. http://www.theses.fr/1998ROUES020.
Full textGachet, David. "Microscopie CARS (Coherent anti-Stokes Raman scattering). Génération du signal au voisinage d'interfaces et à l'intérieur d'une cavité Fabry-Perot." Aix-Marseille 3, 2007. http://www.theses.fr/2007AIX30060.
Full textCoherent anti-Stokes Raman scattering ("CARS") is a spectroscopic technique that gives access to intra-molecular vibrational information. It was first proposed as a contrast mechanism in microscopy in 1982, and was implemented under a convenient colinear configuration in 1999. Since then, the signal generation in CARS microscopy has been studied in the litterature on some simple configurations. In this PhD dissertation, we extend the CARS signal generation study in isotropic media using a full-vectorial formalism. In particular, we introduce CARS signal dependency on the Raman depolarisation ratio and study theoretically its influence on far-field radiation patterns. In another part, we investigate the CARS signal generation in the vicinity of transverse and axial interfaces. On the one hand, a very simple method to obtain background free CARS spectra (i. E. Similar to pure Raman spectra) near transverse interfaces, with conventional excitation, is presented. One the other hand, we show theoretically and experimentally how the excitation detuning modifies the contrast of axial interfaces. These effects are tightly bound to the coherent and resonant nature of CARS. Finally, in order to enhance CARS microscopy sensitivity, we propose to generate the CARS signal near a resonant structure. In this purpose, we lead theoretical and experimental studies of CARS signal generation in a Fabry-Perot cavity. We show how this cavity enhances signal, increases its directivity and symetrise Fwd-CARS and Epi-CARS signals. Such effects are interesting for CARS microscopy. This last study illustrates the electromagnetic environment influence on light emission
Guerrero, prado Patricio. "Reconstruction tridimensionnelle des objets plats du patrimoine à partir du signal de diffusion inélastique." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLV035/document.
Full textThree-dimensional characterization of flat ancient material objects has remained a challenging activity to accomplish by conventional X-ray tomography methods due to their anisotropic morphology and flattened geometry.To overcome the limitations of such methodologies, an imaging modality based on Compton scattering is studied in this work. Classical X-ray tomography treats Compton scattering data as noise in the image formation process, while in Compton scattering tomography the conditions are set such that Compton data become the principal image contrasting agent. Under these conditions, we are able to avoid relative rotations between the sample and the imaging setup. Mathematically this problem is addressed by means of the conical Radon transform. A model of the direct problem is presented where the output of the system is the spectral image obtained from an input object. The inverse problem is addressed to estimate the 3D distribution of the electronic density of the input object from the spectral image. The feasibility of this methodology is supported by numerical simulations
Van, Nevel Alan J. "Wavelet based noise removal for ultrasonic non-destructive evaluation /." free to MU campus, to others for purchase, 1996. http://wwwlib.umi.com/cr/mo/fullcit?p9737876.
Full textBhatia, Navnina. "Scattering correction in cone beam tomography using continuously thickness-adapted kernels." Thesis, Lyon, 2016. http://www.theses.fr/2016LYSEI092.
Full textAdvanced Cone Beam Computed Tomography (CBCT) typically uses a divergent conebeam source and a large area detector. As a result, there an inevitable increase in the size area of illumination causing an increase in the intensity of X-ray scatter signal, both from the object and the detector. This leads to the violation of prime assumption of reconstruction process which is based on straight line integrals path followed by the photons. Consequently scatter artifacts appear in the reconstruction images as steaks, cupping effect and thus produce wrong reconstruction values. Due to the severity of the reconstruction artifact caused by scatter, many scatter corrections methods have been adopted in literature. The first part of this study, reviews most of the existing scatter correction methods. The effect of scattering becomes more prominent and challenging in case of X-ray source of high energy which is used in industrial Non Destructive Testing (NDT), due to higher scatter to primary ratio (SPR). Therefore, in this study, we propose a continuously thickness-adapted deconvolution approach based on improvements in the Scatter Kernel Superposition (SKS) method. In this method, the scatter kernels are analytically parameterized over the whole thickness range of the object under study to better sample the amplitude and shape of kernels with respect to the thickness. The method is tested for both homogeneous and heterogeneous objects as well as simulated and experimental data. Another important aspect of this study is the comprehensive evaluation of contribution of the detector scatter performed using continuous method by separating the contribution of scatter due to the object and the detector. This is performed by modeling the scatter kernels using a four-Gaussian model. In the first approach, we performed this evaluation based on simulation of kernels from Monte Carlo simulations and the corrections are performed on typical industrial experimental data. The results obtained prove that the scatter correction only due to the object is not sufficient to obtain reconstruction image, free from artifacts, as the detector also scatters considerably. In order to prove this point experimentally and to have a better modeling of the detector, we describe a method based on combination of experiments and simulations to calculate the scatter kernels. The results obtained also prove, the contribution of the detector scattering becomes important and the PSF of the detector is not constant as considered in the studies so far, but it varies to a great extend with the energy spectrum
Matzner, Shari. "Model-Based Information Extraction From Synthetic Aperture Radar Signals." PDXScholar, 2011. https://pdxscholar.library.pdx.edu/open_access_etds/248.
Full textR, S. Umesh. "Algorithms for processing polarization-rich optical imaging data." Thesis, Indian Institute of Science, 2004. http://hdl.handle.net/2005/96.
Full textVaraprasad, K. S., and K. S. R. Murthy. "HELICOPTER BORNE TELEMETRY DATA ACQUISITION SYSTEM FOR DOWN RANGE APPLICATIONS." International Foundation for Telemetering, 2005. http://hdl.handle.net/10150/604927.
Full textThe terminal phase telemetry data acquisition has always been a challenging task especially for long and medium range test launches. The task becomes more complicated if the article under test describes a very low altitude cruise terminal phase trajectory. Generally, for long and medium range missions test fired into sea the terminal phase data is acquired by deploying instrumented ships in the vicinity of impact point but beyond the safety corridor. But for long range missions with low altitude cruise terminal phase trajectory and wide safety corridor this conventional approach will not work out because of limitation of LOS from the ship platforms. Hence, for such applications an air borne telemetry receiving system is also to be added to the down range instrumentation network. This paper describes a typical and cost effective air borne system realized utilizing the Commercial Off The Shelf (COTS) products and technology. This paper also addresses as to how the signal scattering problems are tackled in the design implementation.
Mokadem, Azza. "Analysis of scattering by urban areas in the frame of NLOS target detection in SAR images." Thesis, Supélec, 2014. http://www.theses.fr/2014SUPL0004/document.
Full textSynthetic Aperture Radar (SAR) systems have been used since many years for military applications such as the detection of hidden targets. With improved resolutions of these systems, high level of details can be distinguished in the corresponding images. However, some difficulties are encountered when analyzing the SAR images of urban areas. In particular, in these areas, many physical phenomena and interactions occur that make the detection of a target a challenging task. In this framework, the goal of the thesis is to investigate the feasibility of detecting Non Line Of Sight targets inside a simple and representative scene: the urban canyon. A study of the electromagnetic (EM) phenomenology of propagation inside urban canyons has been performed using indoor data at a reduced scale. These data allowed the validation of an EM commercial tool that studies the EM propagation at a real scale. Based on the results of simulation of this code, an in-house code was developed dedicated to predict the detection of a target inside an urban canyon and to analyze the corresponding EM signature. Moreover, this code contributed to a full interpretation of InSAR data of a real complex urban scene with targets
Yoo, Thomas. "Application of a Multimodal Polarimetric Imager to Study the Polarimetric Response of Scattering Media and Microstructures." Thesis, Université Paris-Saclay (ComUE), 2018. http://www.theses.fr/2018SACLX106/document.
Full textThe work carried out during this thesis was aimed to study the interaction of polarized light from the scattering media and particles. This work is part of a strong collaborative context between the LPICM and various private and public laboratories. A wide variety of aspects have been treated deeply, including instrumental development, advanced numerical simulation and the creation of measurement protocols for the interpretation of complex data.The instrumental part of the thesis was devoted to the development of an innovative instrument, suitable for taking polarimetric images at different scales (from millimeters to microns) that can be quickly reconfigured to offer different imaging modes of the same sample. The two main aspects that characterize the instrument are i) the possibility of obtaining real polarimetric images of the sample and the angular distribution of light scattered by an illuminated zone whose size and position can be controlled, ii) the total control of the polarization state, size and divergence of the beams. These two aspects are not united on any other commercial or experimental apparatus today.The first object of the study using the multimodal imaging polarimeter was to study the effect of the thickness from a scattering medium on its optical response. In medical imaging, there is a broad consensus on the benefits of using different polarimetric properties to improve the effectiveness of optical screening techniques for different diseases. Despite these advantages, the interpretation of the polarimetric responses in terms of the physiological properties of tissues has been obscured by the influence of the unknown thickness of the sample.The objective of the work was, therefore, to better understand the dependence of the polarimetric properties of different scattering materials with the known thickness. In conclusion, it is possible to show that the polarimetric properties of the scattering media vary proportionally with the optical path that the light has traveled inside the medium, whereas the degree of polarization depends quadratically on the optical path. This discovery could be used to develop a method of data analysis that overcomes the effect of thickness variations, thus making the measurements very robust and related only to the intrinsic properties of the samples studied.The second object of study was to study the polarimetric responses from particles of micrometric size. The selection of the particles studied by analogy to the size of the cells that form the biological tissues, and which are responsible for the dispersion of light. By means of the polarimetric measurements, it has been discovered that when the microparticles are illuminated with an oblique incidence with respect to the optical axis of the microscope, they appear to behave as if they were optically active. Moreover, it has been found that the value of this apparent optical activity depends on the shape of the particles. The explanation of this phenomenon is based on the appearance of a topological phase of the beam. This topological phase depends on the path of the light scattered inside the microscope. The unprecedented observation of this topological phase has been done by the fact that the multimodal polarimetric imager allows illumination of the samples at the oblique incidence. This discovery can significantly improve the efficiency of optical methods for determining the shape of micro-objects
Zhang, Yuxiang. "Contrôle de santé des matériaux et structures par analyse de la coda ultrasonore." Thesis, Le Mans, 2013. http://www.theses.fr/2013LEMA1014/document.
Full textWith their long and complex propagation paths, coda waves can probe the propagation medium repeatedly and show a high sensitivity to the perturbations to the medium, i.e. variations in propagation velocity. Since such variations may indicate the modification of elastic properties and Coda Wave interferometry (CWI) can determine it precisely (relative resolution of 0.001%), CWI is considered a promising method for non destructive testing and evaluation (NDT&E). An experimental test is presented as an example of the CWI use on concrete for NDT&E purpose. For solving the experimental repeatability issue revealed in this test, a bias-control protocol is designed to reduce the experimental bias in CWI results. It is experimentally confirmed that this protocol can remarkably improve the reliability of CWI results and the experimental repeatability. Together with this bias-control protocol, the CWI is used to study the behaviors of concrete under uni-axial load in direct tension. Both elastic (acoustoealstic effect) and inelastic (Kaiser effect) behaviors are observed via CWI results. Effective value of acoustoelastic coefficient is then determined from CWI results and used for the detection of an early-stage damage that artificially induced to the concrete specimen. A defect-detection method of an initially linear medium (glass) is then developed by using the CWI. Due to the nonlinearity brought by the defects, acoustic mixing effect occurred, and the observation of such effect is the indication of damage. The use of a broadband pump wave and the CWI makes possible to 1) detect the damage globally without blind zone and 2) assess the damage level in an effective manner
Rodeghiero, Giacomo. "Complex Anisotropic Panels and Fast Electromagnetic Imaging – CAP-FELIM." Thesis, Paris 11, 2015. http://www.theses.fr/2015PA112223.
Full textNon-Destructive Testing/Evaluation (NdT/E) of multi-layered composite materials for problems of quality, viability, safety and availability of systems involving manufactured parts (in aeronautics and in automotive industry, as a good example) has become an interesting and challenging task nowadays. The focus of the PhD thesis is on the electromagnetic (EM) imaging of complex anisotropic multi-slab composite panels as increasingly encountered in applications, yet source of strong challenges at modeling stage and even more at often-in-infancy imaging stage. From eddy-currents to microwaves, there is a strong need to make available modeling and imaging procedures that are robust, fast, accurate and useful to potential end-users’ decision about potential defects both at low-frequency (LF) (conductive materials, carbon-fiber like) and high-frequency (HF) (dielectric materials, glass-fiber like). Moreover, it is important to get the results in close-to-real-time. However, this requires an accurate response to external sources of the multilayers, considering the layers which these composite structures are made of as undamaged or damaged. The modeling at forward stage is managed via a first-order solution involving the dyadic Green’s functions (DGF) of the layers along with the depolarization tensor of the assumed defects when they are small enough vis-à-vis the skin depth (LF case) or the wavelength (HF case). The accuracy of the DGF has to be ensured even if the sources lie far away from the origin, which yields a fast-oscillating spectrum of the dyads. The Padua-Domínguez interpolation-integration technique is introduced herein in order to evaluate in an effective fashion fast-oscillating integrals.Damages or disorders, which these composite structures may suffer from, are of many kinds. One could mention voids, fluid-filled cavities or uniaxial defects with obvious impacts on the electromagnetic and geometric parameters of the multilayers. That is, the task to make available to end-users imaging algorithms tailored to detect the presence of defects. The well-known standard MUltiple SIgnal Classification (MUSIC) algorithm, which is based on the Singular Value Decomposition (SVD) of such DGF, is here applied to localize the positions of small multiple defects with weak interaction embedded in anisotropic uniaxial media. The main drawback of MUSIC is its sensitivity with respect to the noise. Therefore, MUSIC with enhanced resolution and Recursively Applied and Projected (RAP) MUSIC are introduced to overcome such a drawback of the standard algorithm and to provide quality results with better resolution
Laleg, Taous-Meriem. "Analyse de signaux par quantification semi-classique. Application à l'analyse des signaux de pression artérielle." Phd thesis, Université de Versailles-Saint Quentin en Yvelines, 2008. http://tel.archives-ouvertes.fr/tel-00357309.
Full textWeser, Robert. "Erfassung und Auswertung von Ultraschallechosignalen zur Charakterisierung konzentrierter disperser Stoffsysteme." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-158895.
Full textWeston, Luke John Henry. "Signals for supersymmetry in photon photon scattering." Thesis, University of Southampton, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.368118.
Full textBouchikhi, Abdelkhalek. "Analyse des signaux AM-FM par Transformation d'Huang Teager: application à l'acoustique sous marine." Phd thesis, Université Rennes 1, 2010. http://tel.archives-ouvertes.fr/tel-00818032.
Full textMeirelles, Gabriela Vaz. "Estudos estruturais e funcionais das proteínas cinases humanas Nek1 e Nek6." [s.n.], 2011. http://repositorio.unicamp.br/jspui/handle/REPOSIP/314351.
Full textTese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia
Made available in DSpace on 2018-08-18T17:04:45Z (GMT). No. of bitstreams: 1 Meirelles_GabrielaVaz_D.pdf: 11269390 bytes, checksum: bfd22a079ffc68a78b96b3e50dd60b1c (MD5) Previous issue date: 2011
Resumo: A proteína NIMA foi identificada e caracterizada funcionalmente em Aspergillus nidulans como sendo uma serina/treonina cinase critica para a progressão do ciclo celular. As Neks (NIMA-related kinases) constituem uma família de cinases composta por 11 membros em mamíferos, que compartilham 40-45% de identidade com a proteína NIMA no domínio catalítico N-terminal. As Neks estão associadas a funções do ciclo celular e diversas patologias, o que as torna potenciais alvos quimioterápicos. Mutações no gene da Nek1 levam ao desenvolvimento da doença renal policistica e ao aparecimento de diversos efeitos pleiotrópicos, sugerindo sua participação em vias reguladoras de vários processos celulares. A Nek6, por sua vez, e ativada durante a mitose, e a super-expressão de mutantes inativos ou a sua depleção por RNAi produz células exibindo defeitos no fuso, anormalidades nucleares, parada na metáfase e apoptose. A Nek6 humana foi recentemente associada a carcinogênese, mas, assim como para a maioria das Neks, sua estrutura molecular, parceiros de interação e vias de sinalização permanecem ainda desconhecidos. Nesse trabalho, introduzimos a hNek6 como uma hub no interactoma humano. Uma extensa comparação de bancos de dados baseada em analises de conectividade mostrou que o quinoma humano e enriquecido em hubs. Nossas redes de interação incluem um amplo espectro de novos parceiros de interação para a hNek6 identificados em screenings de duplo - hibrido em levedura, classificados em 18 categorias funcionais. Alguns novos parceiros de interação da hNek6 são também possíveis substratos e, ainda, colocalizam com a hNek6 e ?-tubulina em células humanas, apontando para uma possível interação centrossomal. Os diversos parceiros de interação conectam a hNek6 a novas vias, como a sinalização de Notch e a regulação do citoesqueleto de actina, ou fornecem novas pistas de como a hNek6 poderia regular vias previamente propostas, como ciclo celular, reparo de DNA e sinalização do NF-?B. Alem disso, obtivemos o primeiro modelo estrutural de baixa resolução para a hNek6 a partir de SAXS. Analises estruturais revelaram que a hNek6 e um monômero em solução, apresentando uma conformação predominantemente globular, mas levemente alongada. Particularmente, a curta região N-terminal desordenada da hNek6 e importante para mediar as interações com seus parceiros. No caso da hNek1, observamos que ela interage com Fez1 e Clasp2 através de seus motivos coiled-coil, e colocaliza com essas proteínas em uma região candidata ao centrossomo
Abstract: NIMA was identified and functionally characterized in Aspergillus nidulans as a critical Ser/Thr kinase for cell cycle progression. The mammalian Neks (NIMA-related kinases) represent an evolutionarily conserved family of 11 serine/threonine kinases that share 40-45% identity with NIMA N-terminal domain. Neks are associated to cell cyclerelated functions and diverse pathologies, which highlight them as potential chemotherapeutic targets. Nek1 gene mutations lead to the development of polycystic kidney disease and the emergence of several pleiotropic effects, suggesting its involvement in pathways regulating various cellular processes. Nek6, in turn, is activated during mitosis, and overexpression of inactive mutants or its depletion by iRNA produces cells exhibiting mitotic spindle defects, nuclear abnormalities, metaphase arrest and apoptosis. Human Nek6 was recently found to be linked to carcinogenesis, but as for the majority of Neks, the molecular structure, interacting partners and signaling pathways remain elusive. Here we introduce hNek6 as a hub kinase in the human interactome. We performed a broad databank comparison based on degree distribution analysis and found that the human kinome is enriched in hubs. Our networks include a large set of novel hNek6 interactors identified in our yeast two-hybrid screens, classified into 18 functional categories. Some novel interactors are also putative substrates and colocalized with hNek6 and ?-tubulin in human cells, pointing to a possible centrosomal interaction. The interacting proteins link hNek6 to novel pathways, e.g. Notch signaling and actin cytoskeleton regulation, or give new insights on how hNek6 may regulate previously proposed pathways such as cell cycle, DNA repair and NF-?B signalings. Furthermore, we obtained the first low-resolution structural model of hNek6 by SAXS. Structural analysis revealed that hNek6 is a monomer in solution with a mostly globular, though slightly elongated conformation. Notably, we found that hNek6 unfolded short N-terminal region is important to mediate the interactions with its partners. In the case of hNek1, we found that it interacts with Fez1 and Clasp2 through coiled-coil motifs and colocalizes with these proteins in a candidate centrosomal region
Doutorado
Bioquimica
Doutor em Biologia Funcional e Molecular
McGuire, John Andrew. "Femtosecond nonlinear spectroscopy at surfaces Second-harmonic probing of hole burning at the Si(111)7x7 surface and fourier-transform sum-frequency vibrational spectroscopy." Berkeley, Calif. : Oak Ridge, Tenn. : Lawrence Berkeley National Laboratory ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/836810-xRj01W/native/.
Full textPublished through the Information Bridge: DOE Scientific and Technical Information. "LBNL--56751" McGuire, John Andrew. USDOE Director. Office of Science. Office of Basic Energy Sciences. Materials Science and Engineering Division (US) 11/24/2004. Report is also available in paper and microfiche from NTIS.
Luo, Linqing. "Time-frequency localisation of distributed Brillouin Optical Time Domain Reflectometry." Thesis, University of Cambridge, 2018. https://www.repository.cam.ac.uk/handle/1810/274568.
Full textBelmonte, Rivas Maria. "Bistatic scattering of global positioning system signals from Arctic sea ice." 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:3273661.
Full textDiong, Mouhamadou. "Développement d'outils statistiques pour l'amélioration de dispositifs d'imagerie acoustique et micro-onde." Thesis, Aix-Marseille, 2015. http://www.theses.fr/2015AIXM4771/document.
Full textImproving the performance of diffraction based imaging systems constitutes a major issue in both acoustic and electromagnetic scattering. To solve this problem, two main approaches can be explored. The first one consists in improving the inversion algorithms used in diffraction based imaging. However, while this approach generally leads to a significant improvement of the performance of the imaging system, it remains limited by the initial amount of information available within the measurements. The second one consists in improving the measurement system in order to maximize the amount of information within the experimental data. This approach does require a quantitative mean of measuring the amount of information available. In estimation problems, the {appraisal of the} performance of the system is often used for that purpose. In this Ph.D. thesis, we use the Cramer Rao bound to assess the performance of the imaging system. In fact, this quantity has the advantage of providing an assessment which is independent from the inversion algorithm used. Two main analysis are discussed in this thesis. The first analysis explores the influence on the system's performance, of several experimental conditions such as the antennas positions, the radiation pattern of the source, the properties of the background medium, etc. Two classes of objects are considered: 2D homogeneous circular cylindrical objects and 2D cylindrical objects with defect. The second analysis studies the performance of an estimator based on Born approximation with the Cramer Rao Bound as reference. The aim of this second analysis is to showcase other possible applications for the Cramer Rao Bound
Ben, Zid Maha. "Emploi de techniques de traitement de signal MIMO pour des applications dédiées réseaux de capteurs sans fil." Thesis, Grenoble, 2012. http://www.theses.fr/2012GRENT017/document.
Full textThe aim of this work is to study from a signal processing point of view the use of MIMO (Multiple Input Multiple Output) communication systems for algorithms dedicated to wireless sensor networks. We investigate energy-constrained wireless sensor networks and we focus on cluster topology of the network. This topology permits for the use of MIMO communication system model. First, we review different aspects that characterize the wireless sensor network. Then, we introduce the existing strategies for energy conservation in the network. The basic concepts of MIMO systems are presented in the second chapter and numerical results are provided for evaluating the performances of MIMO techniques. Of particular interest, polarization diversity over rich scattering environment is studied. Thereafter, beamforming approach is proposed for the development of an original localization algorithm in wireless sensor network. The novel algorithm is described and performances are evaluated by simulation. We determine the optimal system configuration between a pair of clusters that permits for the highest capacity to energy ratio in the fourth chapter. The final chapter is devoted to sensor nodes selection in wireless sensor network. The aim of using such technique is to make energy conservation in the network
Bellomo, Lucio. "Étude et réalisation d'un radar ULB à conjugaison de phase en micro-ondes." Phd thesis, Toulon, 2012. http://tel.archives-ouvertes.fr/tel-00703376.
Full textRouth, H. F. "Scattering of ultrasound by blood with reference to the analysis of doppler signals." Thesis, Bucks New University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380271.
Full textJones, Benjamin A. "Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis /." Thesis, Online version, 2006. http://hdl.handle.net/1912/1283.
Full text"September 2006." Bibliography: p. 89-96.
Jones, Benjamin A. (Benjamin Aaron). "Acoustic scattering of broadband echolocation signals from prey of Blainville's beaked whales : modeling and analysis." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/39228.
Full textThis electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.
Includes bibliographical references (p. 89-96).
Blainville's beaked whales (Mesoplodon densirostris) use broadband, ultrasonic echolocation signals (27 to 57 kHz) to search for, localize, and approach prey that generally consist of mid-water and deep-water fishes and squid. Although it is well known that the spectral characteristics of broadband echoes from marine organisms are a strong function of size, shape, orientation and anatomical group, little is known as to whether or not these or other toothed whales use spectral cues in discriminating between prey and non-prey. In order to study the prey-classification process, a stereo acoustic tag was mounted on a Blainville's beaked whale so that emitted clicks and corresponding echoes from prey could be recorded. A comparison of echoes from prey selected by the whale and those from randomly chosen scatterers suggests that the whale may have, indeed, discriminated between echoes using spectral features and target strengths. Specifically, the whale appears to have favored prey with one or more deep nulls in the echo spectra as well as ones with higher target strength. A three-dimensional, acoustic scattering model is also developed to simulate broadband scattering from squid, a likely prey of the beaked whale.
(cont.) This model applies the distorted wave Born approximation (DWBA) to a weakly-scattering, inhomogeneous body using a combined ray trace and volume integration approach. Scatterer features are represented with volume elements that are small (less than 1=12th of the wavelength) for the frequency range of interest (0 to 120 kHz). Ranges of validity with respect to material properties and numerical considerations are explored using benchmark computations with simpler geometries such as fluid-filled spherical and cylindrical fluid shells. Modeling predictions are compared with published data from live, freely swimming squid. These results, as well as previously published studies, are used in the analysis of the echo spectra of the whale's ensonified targets.
by Benjamin A. Jones.
S.M.
Bel, kamel Emna. "Modélisation du canal en ondes millimétriques pour des applications radar automobile." Thesis, Ecole nationale supérieure Mines-Télécom Atlantique Bretagne Pays de la Loire, 2017. http://www.theses.fr/2017IMTA0042/document.
Full textImproving road safety as well as the development of intelligent transport systems are issues of the future in the automotive sector with a considerable rise of the semi-autonomous and autonomous vehicle. The active safety systems that increasingly equip commercial vehicles use radar sensors (long and short range) operating in the 24 GHz or 77GHz bands. The study and development of such sensors can be facilitated through the use of a generic simulation platform to simulate a radar system coupled to its environment according to predefined standard scenarios. It is then necessary to have a reliable and realistic representation of the environment as well as targets. This thesis deals with the characterization and modelling of the propagation channel for radar applications, in terms of propagation phenomena (multipath, reflection, diffraction …) and electrically large targets. A combination of asymptotic methods was developed for the analysis of electrically large problems in W band, while reducing the requirements in CPU time and memory. The accuracy of the simulator was evaluated with radar cross section measurement of canonical and complex small targets (not exceeding 6 cm) in an anechoic chamber. The developed bench measurement also made it possible to validate an experimental procedure for determining the radar signature. Indeed, the experimental characterization was generalized to characterize various automotive related targets in an “indoor” environment. Measurement results matched well with the results presented in the literature. Moreover, the experimental data allows the extraction of a simple target description in terms of scattering points which model the diffusion and specular reflection phenomena. The high frequency response of a target can be approached by the sum of the responses of its scattering centres. It is thus proposed to simplify the measured signatures in order to increase the computation efficiency. Compared to detailed geometrical representation of a complex target, scattering centre model leads to better efficiency of ray-based propagation simulations of road scenarios. The model also takes into account the scattering centre anisotropy (in the azimuth plan) by modelling their amplitudes by Gaussian ones
Nounouh, Soufiane. "Protocoles de mesure et de calibrage de champs électromagnétiques en vue de l'imagerie par diffraction d'objets faiblement enfouis." Thesis, Aix-Marseille, 2013. http://www.theses.fr/2013AIXM4750/document.
Full textThis thesis is devoted to the development of a microwave system dedicated to subsurface imaging applications. The analysis of the measured wave after the interaction with the medium allows to retrieve the electromagnetic properties of the probed structure. Here, we choose a single frequency operating mode combined with a multistatic configuration in order to improve the information diversity.Quantitative imaging requires a high-precision calibration of the measured data even after a careful correction of experimental errors. Thus, a calibration method is proposed, exploiting the measurement in free-space of the radiation pattern of each antenna. These patterns are quantitatively modeled thanks to an optimized linear combination of elementary sources positioned on the antenna's aperture. This simple and efficient calibration avoids additional measurements with calibration objects. This method provides successful results in a 2D free space scattering problem, as well as in the shallowly buried targets case.The calibrated data serve as inputs to inversion algorithms. As localization is concerned, very satisfactory detection results are obtained. Regarding the characterization aspects, the results indicate that the stratified configuration is less suitable than the free space configuration, due to its lack of spatial information. In order to improve the signal-to-noise ratio, some amendments are made to the experimental configuration (different antennas with or without orientation). Although the permittivity reconstructions are perfectible, the first results are promising especially since no a-priori on the targets has been inserted in the inversion algorithm so far
Ge, Xunyou. "Imagerie ultrarapide à l’échelle nanométrique par diffraction XUV cohérente." Thesis, Paris 11, 2012. http://www.theses.fr/2012PA112361/document.
Full textUltrafast imaging of isolated objects with nanometric spatial resolution is a great challenge in our time. The lensless imaging techniques have shown great potential to answer this challenge. In lensless imaging, one can reconstruct sample images from their diffraction patterns with computational algorithms, which replace the conventional lens systems. Using ultrafast and coherent light sources, such as free electron laser and high order harmonics, one can investigate dynamic phenomena at the femtosecond time scale. In this thesis work, I present the lenless imaging experiments using XUV radiation provided by a laser driven high order harmonic beamline. The manuscript is composed of an introduction, a chapter of theoretical background, three chapters of main research work and a general conclusion with perspectives. The first part of this work concerns the development of the harmonic beamline to optimize the illumination condition for lensless imaging. The second part concentrates on the imaging techniques: the Coherent Diffraction Imaging (CDI), the Fourier Transform Holography (FTH) and the Holography using extended references (HERALDO). The reconstructions have achieved 78 nm spatial resolution in case of CDI and 112 nm resolution in case of HERALDO, both in single-shot regime corresponding to a temporal resolution of 20 fs. The third part presents the first physical application on the harmonic beamline using the lensless imaging. Samples with magnetic nano-domains have been studied with sub-100 nm spatial resolution, which paves the way for ultrafast magnetic dynamic studies. At the end, single-shot 3D imaging and further beamline development have been discussed
DiBenedetto, Michael Francis. "Development of critical-area criteria for protecting microwave landing system azimuth and elevation antenna guidance signals." Ohio University / OhioLINK, 1999. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1175268091.
Full textAlmehmadi, Fares Saleh S. "Secure Chaotic Transmission of Digital and Analog Signals Under Profiled Beam Propagation in Acousto-Optic Bragg Cells with Feedback." University of Dayton / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1426781250.
Full textBlanchette-Guertin, Jean-François. "Seismic energy propagation in highly scattering environments and constraints on lunar interior structure from the scattered signals of the Apollo passive seismic experiment." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/50090.
Full textScience, Faculty of
Earth, Ocean and Atmospheric Sciences, Department of
Graduate
Hennig, Andreas [Verfasser]. "Study of Proton-Neutron Mixed-Symmetry Excitations in 96Ru by Means of Inelastic Proton Scattering and Digital Pulse Processing of Semiconductor Detector Signals / Andreas Hennig." München : Verlag Dr. Hut, 2014. http://d-nb.info/1063221986/34.
Full textKovac, Philip. "Exploring time-dependent approaches towards the calculation of dynamics and spectroscopic signals: A mixed quantum/semiclassical wave packet method and the theory of transient absorption and femtosecond stimulated Raman scattering." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23124.
Full textBoisot, Olivier. "Étude de la rétrodiffusion des surfaces d'eau en bande Ka à faible incidence." Thesis, Toulon, 2015. http://www.theses.fr/2015TOUL0008/document.
Full textThe evolution of the altimetric techniques from Ku-band to Ka-band and the wide swath al-timetry in the context of the SWOT mission (« Surface Water Ocean Topography », CNES/NASA) raises new scientific questions about the validity of the backscattering models from water sur-faces in such a frequency band and errors in estimating water heights from time-evolving water surfaces. A backscattering model (GO4) adapted to the SWOT configuration is introduced. It preserves the accuracy of the referencial Physical Optics model while maintaining the simplicity of the clas-sical Optical Geometrics model. In addition to the classical slope parameter, it introduces another parameter called as « effective curvature » (msc). This model allows the inverson of the surface slope and curvature parameters under certain conditions which are developped in this manus-cript. The joint validity of the backscattering models in Ka-band and from water surfaces is che-cked from controlled wind-wave tank radar measurements . In a last part, the temporal properties of the backscattered signal is studied, in particular the correlation time and the Doppler shift induced by waves motion. Influence of the latters on the non focused SAR synthesis is studied in the context of the SWOT system
Ben, Khadhra Kais. "Surface Parameter Estimation using Bistatic Polarimetric X-band Measurements." Doctoral thesis, Universitätsbibliothek Chemnitz, 2008. http://nbn-resolving.de/urn:nbn:de:bsz:ch1-200801439.
Full textAktuell sind nur sehr wenige Messungen mit bistatischem Radar durchgeführt worden, sei es von Flugzeuggetragenen Systemen oder durch spezielle Aufbauten im Labor. Deshalb basieren die meisten der bekannten Methoden zur Fernerkundung mit Radar auf monostatis-chen Messungen der Rückstreuung des Radarsignals. Diese Methoden, die auf theoretischen, empirischen oder halb-empirischen Modellen basieren, ermöglichen die Schätzung der Oberfächenrauhigkeit und die Bodenfeuchtigkeit (Dielektrizitätskonstante). Im bistatischen Fall wurden bisher nur theoretische Modelle entworfen, die mittels monostatischer Messungen getestet wurden. Aus diesem Grund ist es von großer Bedeutung, Erfahrung und Wissen über die physikalischen Effekte in bistatischen Konfigurationen zu sammeln. Das Hauptziel der vorliegenden Dissertation ist es, anhand vollpolarimetrischer, bistatischer Radarmessungen die Oberfächenrauhigkeit und Bodenfeuchtigkeit zu bestimmen. Im experimentellen Teil der Arbeit werden die Ergebnisse bistatischer Messungen präsentiert, die in der Bistatic Measurement Facility (BMF) des DLR Oberpfaffenhofen aufgenommen wurden. Die Datensätze umfassen Messungen von Böden unterschiedlicher statistischer Rauhigkeit und Feuchtigkeit, die mittels eines Time Domain Reflectivity (TDR) Systems bestimmt werden. Zur Kalibration des BMF wurde die Isolated Antenna Calibration Technique (IACT) verwendet und anhand der Messung der Reflektivität von Wasser überprüft. Im zweiten Teil der vorliegenden Arbeit wird anhand der kalibrierten Daten eine Analyse der Oberflächenstreuung in bistatischen Konfigurationen vorgenommen. Im Anschluss daran wird mittels des Specular Algorithm eine Schätzung der Bodenfeuchte zweier Proben unter- schiedlicher Rauhigkeit (rau und fein) durchgeführt. Ein neues Verfahren zur Schätzung der Oberfächenrauhigkeit, das auf dem kohärenten Term der Integral Equation Method (IEM) basiert, wurde eingeführt. Daneben wird die Empfindlichkeit der Phase sowie der Reflektivität des vorwärtsgestreuten Signals gegenüber Veränderungen der Bodenfeuchtigkeit analysiert. Schließlich werden erste Ergebnisse und Validierungen bistatischer Radarpolarimetrie für den Fall der Vorwärtsstreuung präsentiert