Dissertations / Theses on the topic 'Three-dimensional inversion'
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Debens, Henry Alexander. "Three-dimensional anisotropic full-waveform inversion." Thesis, Imperial College London, 2015. http://hdl.handle.net/10044/1/32407.
Full textBen, Hadj Ali Hafedh. "Three dimensional visco-acoustic frequency domain full waveform inversion." Nice, 2009. http://www.theses.fr/2009NICE4111.
Full textIn seismic exploration, it is crucial to extract from the recorded data the physical of the subsurface in order to correctly locate the potential reservoirs. In this context, seismic imaging is an important step in this quest. The imaging process has been for a long time based on a two-scale strategy : the first step consists in building a smooth velocity model, which correctly explains the kinematics, and the second step in taking into account the dynamics through a migration process to detect reflectivity contrasts. In the eighties, a quantitative imaging method, called waveform inversion, has been proposed to bring together the two stages in an integrated approach. The objective of waveform inversion is to build the whole spectrum of wavenumbers by exploiting all the recorded arrivals acquired by wide aperture acquisitions. The method is formulated as a least squares optimization problem which aims to minimize the differences between the recorded and the modelled data. During the last few years, the waveform inversion method has been a main research topic in the academic and industrial communities. Many issues related to the starting anisotropy and elasticity, and the transition from 2-D to 3-D have been investigated. In this context, the objective of this thesis is to investigate and to develop a waveform inversion approach in the frequency domain and within the visco-acoustic approximation for the reconstruction of a 3-D subsurface model where the model is parametrized by the P-waves velocity, density and attenuation
Commer, Michael. "Three-dimensional inversion of transient electromagnetic data a comparative study /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969850174.
Full textShi, Weiqun 1965. "Advanced modeling and inversion techniques for three-dimensional geoelectrical surveys." Thesis, Massachusetts Institute of Technology, 1998. http://hdl.handle.net/1721.1/9878.
Full textVieira, da Silva Nuno Miguel. "Three-dimensional modelling and inversion of controlled source electromagnetic data." Thesis, Imperial College London, 2011. http://hdl.handle.net/10044/1/9120.
Full textHeath, Philip John. ""Algorithms for the three-dimensional inversion of potential field tensor data" /." Title page, contents and abstract only, 2002. http://web4.library.adelaide.edu.au/theses/09SB/09sbh438.pdf.
Full textFeng, Le. "An in-depth examination of two-dimensional Laplace inversion and application to three-dimensional holography." University of Dayton / OhioLINK, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=dayton1406814392.
Full textGrayver, Alexander [Verfasser]. "Three-dimensional controlled-source electromagnetic inversion using modern computational concepts / Alexander Grayver." Berlin : Freie Universität Berlin, 2013. http://d-nb.info/1036872815/34.
Full textGrayver, Alexander V. [Verfasser]. "Three-dimensional controlled-source electromagnetic inversion using modern computational concepts / Alexander Grayver." Berlin : Freie Universität Berlin, 2013. http://nbn-resolving.de/urn:nbn:de:kobv:188-fudissthesis000000094631-2.
Full textQin, Jizeng. "Three-dimensional DC resistivity forward modeling and inversion by finite-element method." Diss., The University of Arizona, 1995. http://hdl.handle.net/10150/187064.
Full textWilhelms, Wenke. "Development of a three-dimensional all-at-once inversion approach for the magnetotelluric method." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-207548.
Full textHobro, James William Douglas. "Three-dimensional tomographic inversion of combined reflection and refraction seismic travel-time data." Thesis, University of Cambridge, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621515.
Full textWeißflog, Julia. "Three-dimensional individual and joint inversion of direct current resistivity and electromagnetic data." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-220995.
Full textZiel der vorliegenden Arbeit ist die gemeinsame Inversion (\"joint inversion\") elektromagnetischer und geoelektrischer Daten zur Verbesserung des rekonstruierten Leitfähigkeitsmodells. Dabei nutzen wir die verschiedenartigen Sensitivitäten der Methoden aus, um die Auflösung zu erhöhen und ein zuverlässigeres Ergebnis zu erhalten. Um die Arbeit mit mehr als einer Methode zu vereinfachen und eine flexible Softwarebasis auf dem neuesten Stand der Forschung zu etablieren, wurden zwei Codes zur Modellierung und Inversion geoelektrischer als auch elektromagnetischer Daten neu entwickelt, die mit finiten Elementen zweiter Ordnung auf unstrukturierten Gittern arbeiten. Die Vorwärtsoperatoren werden mithilfe analytischer Lösungen und Konvergenzstudien verifiziert, bevor wir ein regularisiertes Gauß-Newton-Verfahren zur Inversion synthetischer Datensätze anwenden. Im Gegensatz zur meistgenutzten \"joint inversion\"-Strategie, bei der verschiedene Daten in einem einzigen Minimierungsproblem kombiniert werden, was in einem großen Gleichungssystem resultiert, stellen wir schließlich einen sequentiellen Ansatz vor, der zyklisch durch die einzelnen Methoden iteriert. So vermeiden wir u.a. eine komplizierte Wichtung der verschiedenen Daten und die Bestimmung aller Regularisierungsparameter in einem Schritt. Der sequentielle Ansatz wird über die Anwendung einer Glättungsregularisierung umgesetzt, bei der die Abweichung der Modellparameter zu einem gegebenen Referenzmodell bestraft wird. Wir nutzen das Ergebnis der vorangegangenen Einzelinversion als Referenzmodell für die folgende Inversion. Der Ansatz wird erfolgreich auf synthetische Datensätze angewendet und wir zeigen, dass die Kombination von mehreren Methoden eine erhebliche Verbesserung des Inversionsergebnisses im Vergleich zu den Einzelinversionen liefert
Pirttijärvi, M. (Markku). "Numerical modeling and inversion of geophysical electromagnetic measurements using a thin plate model." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:951427119X.
Full textMackie, Randall Lee. "Three-dimensional magnetotelluric modeling and inversion with applications to the California Basin and Range Province." Thesis, Massachusetts Institute of Technology, 1991. http://hdl.handle.net/1721.1/13753.
Full textCherevatova, M. (Maria). "Electrical conductivity structure of the lithosphere in western Fennoscandia from three-dimensional magnetotelluric data." Doctoral thesis, Oulun yliopisto, 2014. http://urn.fi/urn:isbn:9789526207100.
Full textTiivistelmä Olemme tutkineet litosfäärin sähkönjohtavuutta Fennoskandian länsiosassa magnetotelluurisen (MT) menetelmän avulla. Fennoskandian länsireuna muokkautui merkittävästi paleotsooisena aikana Kaledonidien vuorijonopoimutuksessa sekä myöhemmin mesotsooisena aikana Laurentia-mantereen repeytyessä ja Atlantin valtameren syntyessä noin 80 miljoonaa vuotta sitten. MT-tutkimukset tehtiin Etelä-Norjassa ja Fennoskandian luoteisosassa. Ensimmäisessä tutkimuksessa kallioperän sähkönjohtavuutta kuvattiin kaksiulotteisilla (2-D) johtavuusmalleilla, jotka ulottuvat Oslosta Norjan rannikolle. Mallien tulkinta viittaa siihen, että maan kuori on pääosin hyvin eristävä lukuun ottamatta muutamaa kuoren ylä- ja keskiosassa olevaa johdekerrosta. Yläkuoren johteet edustavat alunaliuskeita ja keskikuoren johteet todennäköisesti suljetuissa merialtaissa syntyneitä hiilipitoisia sedimenttikerrostumia. Laajempi MT-tutkimus tehtiin ”Magnetotellurics in the Scandes” -hankkeessa. Mittauksia tehtiin 279 mittauspisteessä kesinä 2011–2013. Saadun aineiston avulla voitiin laatia 2-D inversiomallit kuoresta ja ylävaipasta sekä 3-D inversiomalli kuoresta. Tulosten mukaan täällä kuoren yläosa on eristävä kun taas kuoren alaosa on sähköä hyvin johtava. Edellisen lisäksi malleissa näkyy yläkuoren johtavat muodostumat Skellefteån ja Kittilän alueilla, korkean johtavuuden alunaliuskeet Kaledonidien alueella sekä johde Lofoottien alla. Litosfäärin paksuus on noin 200 km mittausverkon pohjoisosassa ja noin 300 km lounaassa. Tämän mukaan litosfääri on paksuin varhaisproterotsooisen litosfäärin alueella, ei arkeeisen litosfäärin alueella vastoin yleistä hypoteesia. Tutkimuksen teoreettisessa osassa kehitettiin sähkömagneettiseen mallinnukseen uusi monitasoiseen diskretisointiin perustuva menetelmä. MT-aineiston 3-D käänteisongelman ratkaisu ja siihen liittyvä suora mallintaminen vaativat suuren laskennallisen kapasiteetin, koska havaintojen ja mallin kuvaamiseen tarvittavien parametrien määrä on erittäin suuri. Moniresoluutio-algoritmi perustuu siihen, että mallin hienojakoisempaa diskretisointia tarvitaan yleensä lähellä maan pintaa kun taas syvemmälle edettäessä, sähkömagneettisen aallon diffuusin etenemisen vuoksi, malli voi olla karkeampi. Tietokonesimulaatioiden mukaan suoritusaika on viidennes ja muistitarve kolmannes verrattuna tavanomaiseen suoran laskennan ”staggered grid” -diskretisointiin
Pritchard, Geoffrey Michael. "Electromagnetic induction in a heterogeneous sphere : a three dimensional inversion for the electrical conductivity of the mantle." Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620942.
Full textKAWAI, HISASHI, KIMINORI BOKURA, SHINJI NAGANAWA, and MASAHIRO YAMAZAKI. "VISUALIZATION OF BRAIN WHITE MATTER TRACTS USING HEAVILY T2-WEIGHTED THREE-DIMENSIONAL FLUID-ATTENUATED INVERSION-RECOVERY MAGNETIC RESONANCE IMAGING." Nagoya University School of Medicine, 2014. http://hdl.handle.net/2237/20547.
Full textIwaki, Asako. "Study on Seismic Wave Propagation Characteristics in a Sedimentary Basin and Waveform Inversion for Three-dimensional Basin Boundary Shape." 京都大学 (Kyoto University), 2011. http://hdl.handle.net/2433/142385.
Full textRhoades, Joshua L. "Characterizing the Distribution of Hydraulic Properties in the Glacial Lake Agassiz Peatlands Using a Three-Dimensional Numerical Model and Regularized Inversion." Fogler Library, University of Maine, 2009. http://www.library.umaine.edu/theses/pdf/RhoadesJL2009.pdf.
Full textZhang, Ting. "Electromagnetic wave imaging of targets buried in a cluttered medium using an hybrid Inversion-DORT method." Phd thesis, Ecole centrale de Marseille, 2014. http://tel.archives-ouvertes.fr/tel-01037906.
Full textChristodoulou, Apostolos A. "Etude sismotectonique et inversion tridimensionnelle en Grèce du Nord." Grenoble 1, 1986. http://www.theses.fr/1986GRE10086.
Full textWeißflog, Julia [Verfasser], Klaus [Akademischer Betreuer] Spitzer, Klaus [Gutachter] Spitzer, Oliver G. [Gutachter] Ernst, and Yuguo [Gutachter] Li. "Three-dimensional individual and joint inversion of direct current resistivity and electromagnetic data / Julia Weißflog ; Gutachter: Klaus Spitzer, Oliver G. Ernst, Yuguo Li ; Betreuer: Klaus Spitzer." Freiberg : Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2017. http://d-nb.info/1221068652/34.
Full textWilhelms, Wenke [Verfasser], Klaus [Akademischer Betreuer] Spitzer, Klaus [Gutachter] Spitzer, Michael [Gutachter] Eiermann, and Dmitry [Gutachter] Avdeev. "Development of a three-dimensional all-at-once inversion approach for the magnetotelluric method / Wenke Wilhelms ; Gutachter: Klaus Spitzer, Michael Eiermann, Dmitry Avdeev ; Betreuer: Klaus Spitzer." Freiberg : Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://d-nb.info/1220912778/34.
Full textHering, Philip [Verfasser], Andreas [Akademischer Betreuer] Junge, Colin [Akademischer Betreuer] Brown, Andreas [Gutachter] Junge, and Colin [Gutachter] Brown. "Advances in magnetotelluric data processing, interpretation and inversion, illustrated by a three-dimensional resistivity model of the Ceboruco volcano / Philip Hering ; Gutachter: Andreas Junge, Colin Brown ; Andreas Junge, Colin Brown." Frankfurt am Main : Universitätsbibliothek Johann Christian Senckenberg, 2019. http://d-nb.info/1226180604/34.
Full textIsmail, Nazli. "Controlled Source Radiomagnetotelluric (CSRMT) Applications in Environmental and Resource Exploration." Doctoral thesis, Uppsala universitet, Geofysik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-102750.
Full textCarcolé, Carrubé Eduard. "Three-dimensional spatial distribution of scatterers in the crust by inversion analysis of s-wave coda envelopes. A case study of Gauribidanur seismic array site (Southern india) and Galeras volcano (South-western Colombia)." Doctoral thesis, Universitat Ramon Llull, 2006. http://hdl.handle.net/10803/9321.
Full textFBP and SIRT are then used to determine the SDS in southern India. Results are almost independent of the inversion method used and they are frequency dependent. They show a remarkably uniform distribution of the scattering strength in the crust around GBA. However, a shallow (0-24 km) strong scattering structure, which is only visible at low frequencies, seems to coincide with de Closepet granitic batholith which is the boundary between the eastern and western parts of the Dharwar craton.
Also, the SDS is estimated for the Galeras volcano, Colombia. Results reveal a highly non-uniform SDS. Strong scatterers show frequency dependence, which is interpreted in terms if the scale of the heterogeneities producing scattering. Two zones of strong scattering are detected: the shallower one is located at a depth from 4 km to 8 km under the summit whereas the deeper one is imaged at a depth of ~37 km from the Earth's surface. Both zones may be correlated with the magmatic plumbing system beneath Galeras volcano. The second strong scattering zone may be probably related to the deeper magma reservoir that feeds the system.
Kubo, Hisahiko. "Study on rupture processes of large interplate earthquakes estimated by fully Bayesian source inversions using multi period-band strong-motion data -The 2011 Tohoku-oki and the 2011 Ibaraki-oki earthquakes-." 京都大学 (Kyoto University), 2015. http://hdl.handle.net/2433/199110.
Full textGuilbaud, Claude. "Étude des inversions thermiques : application aux écoulements atmospghériques dans des vallées encaissées." Université Joseph Fourier (Grenoble), 1996. http://www.theses.fr/1996GRE10068.
Full textBazin, Sara. "Three-dimensional crustal structure of East Pacific rise discontinuities from tomographic inversions /." Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2000. http://wwwlib.umi.com/cr/ucsd/fullcit?p3035403.
Full textToomey, Douglas R. "The tectonics and three-dimensional structure of spreading centers--microearthquake studies and tomographic inversions." Thesis, Massachusetts Institute of Technology, 1987. http://hdl.handle.net/1721.1/58497.
Full textSupervised by Mike Purdy, Sean C. Solomon.
Includes bibliographical references.
Two-thirds of the Earth's surface has been formed along a global system of spreading centers that are presently manifested in several different structural forms, including the classic rift valley of the Mid-Atlantic Ridge, the more morphologically subdued East Pacific Rise, and the pronounced en echelon structure of the Reykjanes Peninsula within southwestern Iceland. In this thesis, each of these different spreading centers is investigated with microearthquake studies or tomographic inversion of travel times. Results of these studies are used to constrain the spatial variability of physical properties and processes beneath the axis of spreading and, together with other observations, the temporal characteristics of crustal accretion and rifting. In Chapter 2 the theoretical basis of seismic body-wave travel-time tomography and techniques for the simultaneous inversion for hypocentral parameters and velocity structure are reviewed. A functional analysis approach assures that the theoretical results are independent of model parameterization. An important aspect of this review is the demonstration that travel time anomalies due to path and source effects are nearly independent. The discussion of the simultaneous inverse technique examines theoretically the dependence of tomographic images on the parameterization of the velocity model. In particular, the effects of parameterization on model resolution are examined, and it is shown that an optimum set of parameters averages velocity over localized volumes. Chapter 2 ends with the presentation of the results of tomographic inversions of synthetic data generated for a model of the axial magma chamber postulated to exist beneath the East Pacific Rise. These inversions demonstrate the power of the tomographic method for imaging three-dimensional structure on a scale appropriate to heterogeneity along a spreading ridge axis. Chapter 3 is the first of two chapters that present the results of a microearthquake experiment carried out within the median valley of the Mid-Atlantic Ridge near 230 N during a three week period in early 1982. In this chapter, the experiment site, the seismic network, the relocation of instruments by acoustic ranging, the hypocenter location method, and the treatment of arrival time data are described. Moreover, hypocentral parameters of the 26 largest microearthquakes are reported; 18 of these events have epicenters and focal depths which are resolvable to within ±1 km formal error at the 95% confidence level. Microearthquakes occur beneath the inner floor of the median valley and have focal depths generally between 5 and 8 km beneath the seafloor. Composite fault plane solutions for two spatially related groups of microearthquakes beneath the inner floor indicate normal faulting along fault planes that dip at angles of 300 or more.
Douglas Ray Toomey.
Ph.D.
Migliari, Wellington. "From the effectiveness of the right to housing to the right to the city: a three-dimensional rationality for Brazil and Spain." Doctoral thesis, Universitat de Barcelona, 2018. http://hdl.handle.net/10803/664047.
Full textEl conflicto entre el sistema de propiedad y el derecho a la vivienda se ha convertido en una investigación más compleja desde el comienzo del presente trabajo. Nuestro análisis inicial sobre la efectividad de la función social de la propiedad identificó en decisiones de tribunales un ejercicio de comprensión muy estricto del concepto de propiedad. La percepción liberal de la no injerencia en la economía del mercado inmobiliario redujo el debate legal sobre los límites internos de la propiedad a una relación binaria financiera, por ejemplo, individuos afectados por hipotecas e instituciones de crédito, inquilinos y propietarios no residenciales, familias que viven en condiciones de vulnerabilidad socioeconómica e inversores. Sin embargo, la vivienda causa todavía cierta inquietud jurídica, ya que el número de propiedades no ocupadas y el costo de los alquileres siguen aumentando en Brasil y España. Examinando los datos disponibles para ambos países, encontramos una variable macroeconómica en el desarrollo urbano y el acceso a la vivienda íntimamente vinculados a los mercados bursátiles. Además, la noción absoluta de derecho de propiedad sigue siendo un obstáculo heredado de la civil law que impide la apertura del sistema de propiedad en su dimensión social. El objetivo de nuestra tesis es contribuir a la defensa efectiva del derecho a la vivienda como instrumento jurídico asociado a la función social de la propiedad y como factor de conexión con otros derechos en el contexto urbano. Nuestra hipótesis requiere una racionalidad tridimensional para juicios adecuados más allá de la tarea de los tribunales. Un conjunto de razones de cómo las dos sociedades pueden limitar la especulación inmobiliaria transnacional, superar la tradición del civil law en tensión inerte con las soberanías democráticas y utilizar la función social como categoría jurídica para que la efectividad del derecho a la vivienda sirva de punto de inflexión para el derecho a la ciudad.
O conflito entre o sistema de propriedade e o direito à moradia tornou-se uma indagação mais complexa desde o início da presente pesquisa. Nossa análise inicial sobre a eficácia da função social da propriedade identificou em decisões judiciais um exercício de compreensão muito estreita sobre o conceito de propriedade. A percepção liberal da não interferência na economia do mercado imobiliário reduziu o debate jurídico sobre os limites internos da propriedade para vínculos financeiros binários, por exemplo, pessoas afetadas por inadimplência de suas hipotecas versus instituições de crédito, inquilinos contra propriedades de pessoas jurídicas, famílias em condições de vulnerabilidade socioeconômica contra investidores. No entanto, a habitação ainda causa alguma inquietude legal, já que o número de imóveis desocupados e o custo de aluguéis continuam a aumentar no Brasil e na Espanha. Com base em análise de dados disponíveis para ambas realidades, encontramos uma variável macroeconômica no desenvolvimento urbano e o acesso a moradias intimamente ligados aos mercados de ações. Além disso, a noção absoluta sobre o direito de propriedade continua a ser um obstáculo herdado da tradição do direito civil que impede a abertura do sistema de propriedade a dimensões sociais. O objetivo da nossa tese é contribuir para a defesa efetiva do direito à moradia como instrumento jurídico associado à função social da propriedade e como fator de conexão para outros direitos em contexto urbano. Nossa hipótese requer uma racionalidade tridimensional para julgamentos adequados além da tarefa dos tribunais. Um conjunto de razões sobre como as duas sociedades podem limitar a especulação imobiliária transnacional, superar a tradição do direito civil em tensão inerte com soberanias democráticas e usar a função social como uma categoria legal para que a efetividade do direito à habitação sirva enquanto ponto de inflexão para o direito à cidade.
Lima, Frederico Romagnoli Silveira. "Modelagem tridimensional de problemas inversos em condução de calor: aplicação em problemas de usinagem." Universidade Federal de Uberlândia, 2001. https://repositorio.ufu.br/handle/123456789/14793.
Full textThis work proposes a methodology to obtain the transient cutting tool temperature. The physical phenomenon is treated by a three-dimensional analysis. The inverse heat conduction technique is proposed to estimate the generated heat flux on the rake face of the tool. This technique is based on conjugate gradient method with adjoint equation. The machining process is instrumented with thermocouples at the bottom face of the tool, opposite to its main rake face. The signals are automatically received and processed using a data acquisition system and a PC-Pentium. The direct solution is numerically solved using finite volumes method with the heat flux estimated. The experimental data are processed using a computational algorithm developed specifically for inverse heat flux estimation in machining processes. Experimental temperatures are obtained during several cutting tests using cemented carbide and ceramic tools. The influence of the cutting parameters on the temperature distribution is verified. An error analysis of the results is also presented.
O objetivo deste trabalho é propor uma metodologia para a obtenção da distribuição da temperatura na superfície de corte da ferramenta em um processo de usinagem por torneamento. Nesse sentido, o problema térmico de usinagem é caracterizado de maneira bem realista através de uma abordagem tridimensional. Para a obtenção dos campos térmicos na região de corte propõe-se o uso de técnicas de problemas inversos em condução de calor. Assim, a solução do problema térmico é obtida em duas etapas: solução inversa e solução direta. A solução inversa baseia-se no método do gradiente conjugado e da equação adjunta para a estimar o fluxo de calor gerado na região de corte que flui para a ferramenta. Nesse caso, são usados termopares soldados na face oposta da ferramenta que fornecem a informação necessária para que a solução inversa consiga estimar o fluxo de calor. Com a obtenção do fluxo de calor que flui para a ferramenta utiliza-se a solução direta do problema térmico para o cálculo da temperatura na região de corte. A implementação computacional da solução inversa e da solução direta é apresentada sob a forma de um programa de computador intitulado GRAD3D 1.0. Nesse programa, além da solução proposta para o problema térmico de usinagem é possível simular numericamente problemas térmicos correlatos. Testes experimentais unidimensionais e tridimensionais com condições controladas são apresentados para a validação do algoritmo computacional. Nos testes experimentais de usinagem, a aplicabilidade da técnica proposta é avaliada para o processo de usinagem por torneamento de uma barra de ferro fundido cinzento usando-se ferramentas de metal duro (WC) e de cerâmica (Si3N4). Apresenta-se ainda uma análise dos erros que podem estar presentes nos resultados obtidos.
Doutor em Engenharia Mecânica
Lizar, Jéssica Caroline. "Comparação dosimétrica 3D de tratamentos de câncer de mama com técnica conformacional 3D usando filtros e com IMRT direto e inverso na presença do movimento respiratório." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/59/59135/tde-30082017-152201/.
Full textExternal postoperative radiotherapy in women diagnosed with early stage breast cancer is considered as a standard procedure, however during planning for target volume irradiation as possible dosimetric uncertainties reabsorption of the patient\'s intrinsic respiratory movement are disregarded. This study evaluates not only the influence of respiration on the three-dimensional distribution of the dose but how this distribution is modified due to the radiotherapy technique used for treatment. Three planning techniques were analyzed: three-dimensional conformational radiotherapy (3D-RT) with filters, intensity-modulated radiotherapy (IMRT) using direct planning and inverse IMRT. In order to simulate the movement of contraction and expansion of the chest wall, a platform with predetermined oscillation amplitudes was used, the oscillation frequency was provided by a variable voltage source. To simulate the breast, semi-spherical simulator objects filled with dosimetric gel (MAGIC-f) were used. The plannnings for each technique were performed on the computerized tomography (CT) of the simulator object filled with water in static mode. Three batches of gel dosimeters were prepared for the project, each batch was irradiated with a different radiothermic technique and comprised five simulator objects and a set of nine calibration tubes filled with MAGIC-f gel. The first simulator objects is used as reference, the second is irradiated in the static mode, the others are irradiated using different amplitudes, respectively: 0,34 cm, 0,88 cm and 1,22 cm. Volumetric dose information was obtained using Nuclear Magnetic Resonance Imaging, each batch was scanned with a multi spin echo sequence and the dose-related relaxometry maps were extracted in a software developed and improved by our Group of research. The quantitative comparison of the relaxometry maps of the moving simulator objects with respect to the static mode was performed by the three-dimensional gamma index (3% / 3mm / 15% threshold). For the 3D-RT, the percentage of approved points of the static object with respect to the oscillator in the amplitude of 0.34 cm was 96.44%, for amplitude of 0.88 cm was 93.23% and for amplitude of 1.22 cm was 91.65%. For the direct IMRT the percentage of approved points of the static object in relation to the oscillator in the amplitude of 0.34 cm was 98.42%, for amplitude of 0.88 cm was 95.66% and for amplitude of 1.22 cm was 94.31%. For the inverse IMRT, the percentage of approved points of the static object in relation to the oscillator in the amplitude of 0.34 cm was 94.49%, for amplitude of 0.88 cm was 93.51% and for amplitude of 1.22 cm was 86.62%. From the results, it is inferred that a low-amplitude respiratory movement, for breast cancer treatments, is not a worrying factor for clinical routine, however, increasing the amplitude of the oscillation increases the inomogeneity of the dose and this affects the dosimetry parameters of the target volume coverage. It was observed that the dose distribution changes with the technique in use and in the case of the inverse IMRT for amplitude of oscillation of 1.22 cm, less than 90% of points were approved in the gamma index evaluation
Carvalho, Solidônio Rodrigues de. "Determinação do campo de temperatura em ferramentas de corte durante um processo de usinagem por torneamento." Universidade Federal de Uberlândia, 2005. https://repositorio.ufu.br/handle/123456789/14729.
Full textDuring machining, high temperatures are generated in the region of the tool cutting edge, and these temperatures have a controlling influence on the wear rate of the cutting tool and on the friction between the chip and the tool. However, direct measurement of temperature using contact type sensors at the tool-work interface is difficult to implement due to the rotating movement of the workpiece and the presence of the chip. Therefore, the use of inverse heat conduction techniques represents a good alternative since these techniques takes into account temperatures measured from accessible positions. This work proposes a new experimental methodology to determine the thermal fields and the heat generated in the chiptool interface during machining process using inverse problems techniques. This work develops a numerical 3-D transient thermal model that takes into account both the tool and toolholder assembly. The thermal model represents the direct problem and is solved using finite volume techniques on a non uniform mesh. The related inverse problem is solved by using the golden section technique. The experimental data and inverse technique are processed using a computational algorithm developed specifically for inverse heat flux estimation in manufacturing processes called INV3D. An error analysis of the results and the experimental procedures to determine the cut area and the tool holder temperature are also presented. Besides the machining problem, INV3D is also able to solve different thermal problems. As an example of its generality, this work also presents an application of this software in the thermal fields study during a welding process.
Durante a usinagem de metais, altas temperaturas são geradas na interface de cavacoferramenta. Essas temperaturas, por sua vez, têm forte influência no controle da taxa de remoção de material e no atrito entre o cavaco e a ferramenta de corte. Observa-se, entretanto que a medição direta de temperaturas nessa região é de difícil execução devido ao movimento da peça e a presença do cavaco. Assim, o uso de técnicas inversas em condução de calor se apresenta como uma boa alternativa para a obtenção dessas temperaturas uma vez que essas técnicas permitem o uso de dados experimentais obtidos em regiões acessíveis. Este trabalho propõe uma nova metodologia experimental para a determinação dos campos térmicos e do fluxo térmico gerado em ferramentas de corte durante um processo de torneamento. Uma das inovações apresentadas é o desenvolvimento de um modelo térmico tridimensional transiente que considera além da ferramenta de corte, o conjunto ferramenta, calço e porta-ferramenta. O problema direto é então resolvido numericamente usando-se diferenças finitas a partir de uma malha de discretização não uniforme. O problema inverso, por sua vez, é resolvido por meio da técnica de otimização da seção áurea. Para a solução dos problemas envolvidos, desenvolveu-se um código computacional específico, denominado INV3D. O programa INV3D contém ainda uma série de funções que auxiliam na aquisição dos dados experimentais, na geração da malha tridimensional e na análise em ambiente gráfico. O trabalho apresenta também os procedimentos experimentais usados na medição das temperaturas na ferramenta, calço e porta-ferramenta e na identificação da área de interface de corte. Os resultados obtidos são validados por meio de experimentos controlados em laboratório e de análises qualitativas. Além do problema de usinagem investigado, como exemplo da generalidade do Inv3D na solução de problemas térmicos, apresenta-se também uma aplicação deste software no estudo de campos térmicos decorrentes de um processo de soldagem TIG em alumínio.
Doutor em Engenharia Mecânica
Li, Yaoguo. "Inversion of three-dimensional direct current resistivity data." Thesis, 1992. http://hdl.handle.net/2429/3142.
Full textBender, Christopher Matthew. "Three-dimensional geoacoustic perturbative inverse technique for the shallow ocean water column." 2012. http://hdl.handle.net/2152/19707.
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Weißflog, Julia. "Three-dimensional individual and joint inversion of direct current resistivity and electromagnetic data." Doctoral thesis, 2016. https://tubaf.qucosa.de/id/qucosa%3A23113.
Full textZiel der vorliegenden Arbeit ist die gemeinsame Inversion (\"joint inversion\") elektromagnetischer und geoelektrischer Daten zur Verbesserung des rekonstruierten Leitfähigkeitsmodells. Dabei nutzen wir die verschiedenartigen Sensitivitäten der Methoden aus, um die Auflösung zu erhöhen und ein zuverlässigeres Ergebnis zu erhalten. Um die Arbeit mit mehr als einer Methode zu vereinfachen und eine flexible Softwarebasis auf dem neuesten Stand der Forschung zu etablieren, wurden zwei Codes zur Modellierung und Inversion geoelektrischer als auch elektromagnetischer Daten neu entwickelt, die mit finiten Elementen zweiter Ordnung auf unstrukturierten Gittern arbeiten. Die Vorwärtsoperatoren werden mithilfe analytischer Lösungen und Konvergenzstudien verifiziert, bevor wir ein regularisiertes Gauß-Newton-Verfahren zur Inversion synthetischer Datensätze anwenden. Im Gegensatz zur meistgenutzten \"joint inversion\"-Strategie, bei der verschiedene Daten in einem einzigen Minimierungsproblem kombiniert werden, was in einem großen Gleichungssystem resultiert, stellen wir schließlich einen sequentiellen Ansatz vor, der zyklisch durch die einzelnen Methoden iteriert. So vermeiden wir u.a. eine komplizierte Wichtung der verschiedenen Daten und die Bestimmung aller Regularisierungsparameter in einem Schritt. Der sequentielle Ansatz wird über die Anwendung einer Glättungsregularisierung umgesetzt, bei der die Abweichung der Modellparameter zu einem gegebenen Referenzmodell bestraft wird. Wir nutzen das Ergebnis der vorangegangenen Einzelinversion als Referenzmodell für die folgende Inversion. Der Ansatz wird erfolgreich auf synthetische Datensätze angewendet und wir zeigen, dass die Kombination von mehreren Methoden eine erhebliche Verbesserung des Inversionsergebnisses im Vergleich zu den Einzelinversionen liefert.
Commer, Michael [Verfasser]. "Three-dimensional inversion of transient electromagnetic data : a comparative study / vorgelegt von Michael Commer." 2003. http://d-nb.info/969850174/34.
Full textFathi, Arash. "Full-waveform inversion in three-dimensional PML-truncated elastic media : theory, computations, and field experiments." Thesis, 2015. http://hdl.handle.net/2152/30515.
Full textChen, Wan-Li, and 陳宛勵. "On Three-Dimensional Stress Altered Hole Inversion-Layer Mobility in (001) and (110) p-MOSFETs." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/56506337595782478085.
Full text國立交通大學
電子研究所
101
Hole inversion-layer mobility under three-dimensional stresses in (001)/<110> and (110)/<110> of p-MOSFETs is investigated by using a self-consistent six-band k‧p solver. The three significant scattering mechanisms are included: optical phonon scattering, acoustic phonon scattering, and surface roughness scattering with the screening effect taken into account. This leads to a clearer physical insight into 3-D-stress-induced hole mobility change in terms of three parts: (1) effect of strained k‧p deformation potentials a, b, and d; (2) phonon-limited and/or surface-roughness-limited mobility change; and (3) scattering-time-limited and conductivity-effective-mass-limited mobility change. Finally, the conclusions indicate that (1) for the effect of the hole mobility change, a is weak, b is moderate, and d is strong, particularly for the uniaxial compressive stress in the <110> direction. The experimentally-calibrated values are: a = 2.46eV, b = -1.6 ~ -2.1eV, and d = -3.1eV; (2) the phonon-limited mobility change is more stress-sensitive than the surface-roughness-limited one; and (3) the mobility change ratio can be related to the reversely proportional conductivity effective mass and density-of-states effective mass in the absence of the surface roughness mobility change.
Hole, John A. "Structure of the Queen Charlotte Basin and underlying crust from modelling and inversion of three-dimensional seismic refraction data." Thesis, 1993. http://hdl.handle.net/2429/2180.
Full textBai, Chao-Ying. "Three dimensional seismic kinematic inversion with application to reconstruction of the velocity structure of Rabaul volcano / by Chao-ying Bai." 2004. http://hdl.handle.net/2440/22132.
Full textBibliography: leaves 215-230.
viii, 230 leaves : ill., maps ; 30 cm.
Title page, contents and abstract only. The complete thesis in print form is available from the University Library.
Thesis (Ph.D.)--University of Adelaide, School of Chemistry and Physics, Discipline of Physics, 2004
Bai, Chao-ying. "Three dimensional seismic kinematic inversion with application to reconstruction of the velocity structure of Rabaul volcano / by Chao-ying Bai." Thesis, 2004. http://hdl.handle.net/2440/22132.
Full textSoeffky, P. "Delineating the deep crustal fluid link between the Paralana Enhanced Geothermal System and the Beverley Uranium Mine using magnetotellurics." Thesis, 2012. http://hdl.handle.net/2440/95486.
Full textThe global demand for clean energy alternatives is constantly increasing, creating significant interest for more sustainable energy resources such as uranium and geothermal. Australia is host to over 25% of the world's known uranium resources as well as having significant geothermal potential. The Mount Painter Domain, in the Northern Flinders Ranges in South Australia, is in a region of anomalously high heat flow generated by radiogenic decay of uranium and thorium rich granites. Two distinct uranium deposits have formed from dissolved uranium carried from the ranges by fluids, being deposited where reduction in sediment pH precipitates uranium. In May 2012 a magnetotelluric profile was collected, extending from the Northern Flinders Ranges to the Lake Frome embayment to help constrain existing resistivity models. Precipitation of uranium at the Beverley Mine site is anomalous as no surface water flow is present, suggesting the presence of subsurface processes. This pathway is linked to a 50m conductive body at the brittle-ductile boundary of the mid-crust, directly under the Paralana geothermal prospect. 3D modelling of the Paralana geothermal prospect suggests deep conductive features connecting with features at the surface.
Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Earth and Environmental Sciences, 2012
Lee, Chien-Chih, and 李建志. "A New In-House Fast Sophisticated Quantum Simulator for Silicon Hole Band Structure and Inversion-Layer Mobility under Three-Dimensional GPa-Level Stresses." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/10883282420260933054.
Full text國立交通大學
電子研究所
101
The continuously scaled electronic devices encounter not only the extra quantum confinement (no matter from the field confinement or from the space confinement) but also the complicated mechanical stresses (no matter the intentional or unintentional stressors along the arbitrary directions). Both of these two phenomena cause the crucial impacts on the valence-band structure which can greatly alter the hole electrical properties. In other words, these lead to the extra complexities and the heavy computation burden in the theoretical work. Since the evaluation of the hole electrical properties such as hole mobility fully rely on the valence subband structures, with no surprise the precise and fine quality of valence subband structures are urgently required to achieve the satisfactory calculations. With the six-band k•p Schrödinger-Poisson self-consistent method this dissertation will focus on the hole electrical properties in p-type inversion layer of the electronic devices via the self-developed simulator, p-NEP (abbreviation of p-type Nano Electronics Physics). The main purpose of the dissertation is to investigate the hole electrical properties in silicon inversion layer beneath on the significant quantum confinement and the complicated mechanical stresses. Based on this main topic, the organization of this dissertation is described below. First, an introduction to the valence band structures in p-type inversion layer is described. Then, the dissertation is focused on the numerical techniques and physical models of p-NEP. However, according to the algorithm of p-NEP, the CPU time is extraordinarily long. To overcome the issue, we present a novel computational accelerator to intrinsically boost a self-consistent six-band k•p Schrödinger-Poisson simulation. This accelerator comprises a triangular potential based six-band k•p simulator, a hole effective mass approximation (EMA) technique, and an electron analogue version of the self-consistent Schrödinger and Poisson’s equations solver. The outcome of the accelerator furnishes the initial solution of the confining electrostatic potential and is likely to be close to the realistic one, valid for different temperatures, substrate doping concentrations, inversion hole densities, and surface orientations. The results on (001) and (110) substrates are supported by those published in the literature. The overall CPU time is reduced down to around 8% of that without the accelerator. The application of the proposed accelerator to more general situations is projected as well. Secondly, according to three distinct sets of the bulk oriented Luttinger parameters γ1, γ2, and γ3, the validity of the bulk oriented Luttinger parameters in the six-band k•p Schrödinger-Poisson self-consistent method is confirmed. With the the bulk oriented Luttinger parameters, the realistic hole subband structures in (110) p-MOSFETs can be well reproduced in comparison with the recent Shubnikov-de Haas (SdH) oscillation experiment by Takahashi, et al. Thirdly, the hole mobility change for GPa-level uniaxial stresses along each of three crystallographic directions are distinguished into four contributing componds: (i) phonon-limited, (ii) surface-roughness-limited, (iii) scattering-time-limited, and (iv) conductive-mass-limited mobility changes. It is also dedicated to three key strain-related material parameters, namely the Bir-Pikus deformation potentials a□, b, and d, which are widespread in magnitude. To improve such large discrepancies, we conduct sophisticated calculations on <110>/(001) and <110>/(110) hole inversion-layer mobility. We find that, to affect the calculated hole mobility enhancement, a□ is weak, b is moderate, and d is strong, particularly for the uniaxial compressive stress along the <110> direction. This provides guidelines for an experimental determination of the primary factor, d, and the secondary factor, b, with the commonly used values for a□. The user interface (UI) and simulation process of p-NEP are further demonstrated. The resulting subbnad structures, threshold voltage, capacitance, and gate direct tunneling current are all addressed. Finally, we summarize the conclusions of our works.
Hsieh, Ming-Che, and 謝銘哲. "Efficient waveform inversions for finite-source models of moderate and large earthquakes in three-dimensional structures." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/06919330181140364420.
Full text國立中央大學
地球科學學系
103
For hazard mitigation and risk assessment, an efficient and well-designed algorithm to determine earthquake rupture properties in a short time is on demand. It is also important to account for effects of surface and subsurface structures to wave propagation and predict ground motion more accurately. In this thesis, we have developed an efficient three-step process which is used in solving for a finite-source model: A point-source focal mechanism is determined in the first step. Then, the two nodal planes in the point-source solution are used as trial candidates to solve for an average finite-rupture model and identify the actual fault plane. In the final step, a full slip distribution inversion is carried out based on the identified fault plane. We have adopted the source determination scheme to earthquakes near Nantou in central Taiwan for tectonic interpretations. We solved for the rupture properties of a series of moderate events (MW≈6), which show similar focal mechanisms but with different focal depths. Our determination on the rupture planes of these earthquakes suggest that the most of the shallow-focus ruptures occur on the low-angle plane, but on the high-angle plane for most of the deeper events, consistent with the background seismicity and support the existence of tectonically co-located active conjugate faulting system in central Taiwan. We also demonstrated the slip distribution inversion of a moderate earthquake in eastern Taiwan by our three-step procedure. Both broadband and strong motion stations are included in the inversion. Our results show that three-dimensional velocity model could provide better waveform fittings than one-dimensional model, and slip distribution is much more concentrated. Applications to moderate events (MW≈6) in southeastern and eastern Taiwan show that our source inversion technique is effective for semi-automatic, near real-time determinations of finite-source parameters for seismic hazard mitigation purposes.