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1
Wu, Hsiao-hung Iris. "Generalized inversion and theory of agree." Thesis, Massachusetts Institute of Technology, 2008. http://hdl.handle.net/1721.1/45894.
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Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Linguistics and Philosophy, 2008.Includes bibliographical references (leaves 158-165).
In this thesis I examine some of the fundamental questions surrounding inversion structures. I first provide an analysis of Locative Inversion. I show that the mixed A- and A- syntactic behavior of the fronted PP in English could be derived once we understand how the featural composition of locative phrases influences on the Probe-Goal relation between C and the postverbal DP. In particular, I argue that there is a correlation between syntactic categories of locative phrases and typological differences in the syntactic patterns in Locative Inversion: in Mandarin Chinese, Chichewa, Kinande and Gungbe, locatives are (or can be) represented by nominal categories (i.e. equipped with complete cp-features) and these locatives exhibit pure A-properties in Locative Inversion; in English and Sesotho, however, they are characteristically represented by non-nominal categories and the locative phrases are thus forced to undergo two-step movement from an Aposition to an A-position as avoidance of intervention effects in the Agree system.I also discuss a variety of (generalized) inversion constructions, including English Quotative Inversion, Sentential Subject and French Stylistic Inversion. In these constructions I show that since a cp-deficient constituent moves to [Spec, TP], additional operations (such as topicalization) have to take place so as to destroy the potentially offending structure created by the fronted defective elements.
(cont.) Specifically, I suggest that these are related constructions because they all display a mixture of A- and A- properties.Finally I focus on the generalization concerning the placement restrictions of arguments by Spell-Out, in particular the principles that force argument externalization from the vP and VP. I argue that argument externalization is motivated by Case-related concerns.
by Hsiao-hung Iris Wu.
Ph.D.
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Wilson, Adam. "Theory and methods of frequency-dependent AVO Inversion." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4740.
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Amplitude-versus-offset, AVO, approximations allow the estimation of various properties from pre-stack seismic gathers. Recently it has been suggested that fluid mobility is a controlling factor in pore pressure equalisation and can result in anomalous velocity dispersion in the seismic bandwidth. However, current approximations all assume an elastic subsurface and are unable to account for velocity dispersion. I have applied existing methodologies to a real dataset to qualitatively detect and interpret spectral amplitude anomalies. Three areas had AVO and spectral signature consistent with frequency-dependent AVO theory. The results suggest that it is feasible to measure such effects on real data in the presence of random noise. It would imply that the relaxation parameter, tau, is larger in the field than has been measured in water-saturated real and synthetic sandstones in the laboratory. I extended a two-term AVO approximation by accounting for velocity dispersion and showed how the resultant reflection coefficient becomes frequency-dependent. I then used this to measure P- and S-wave reflectivity dispersion using spectrally-balanced amplitudes. The inversion was able to quantify the affect of the P-wave velocity dispersion as an instantaneous effect on the reflection. NMO stretch was an issue at the far offsets and I limited myself to the near offsets and effectively measured only the P-wave reflectivity dispersion. I showed how the P-wave reflectivity dispersion signs depend on the AVO classification of the reflection whilst the magnitude depends on the crack density of my model. I showed how the effect of noise and thin-bed tuning can enter uncertainties into the interpretation of spectral anomalies. Whilst it is possible to detect frequency-dependent AVO signatures on pre-stack gathers, the interpretation remains non-unique. I have quantitatively measured a new physical property, reflectivity dispersion, from pre-stack seismic data. I have presented a method of detecting and measuring velocity dispersion in pre-stack gathers but there remain ambiguities in the interpretation of such results. The approach incorporates spectrally decomposed data in an extended AVO inversion scheme. Future work should investigate the application of the methodology to a real seismic dataset.
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Hashemi-Zahan, Saeid. "Inversion of non-minimum phase systems in signal processing." Thesis, University of Southampton, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.266944.
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Rattan, Amarpreet. "Character Polynomials and Lagrange Inversion." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1029.
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In this thesis, we investigate two expressions for symmetric group characters: Kerov?s universal character polynomials and Stanley?s character polynomials. We give a new explicit form for Kerov?s polynomials, which exactly evaluate the characters of the symmetric group scaled by degree and a constant. We use this explicit expression to obtain specific information about Kerov polynomials, including partial answers to positivity questions. We then use the expression obtained for Kerov?s polynomials to obtain results about Stanley?s character polynomials.
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Zou, Qingze. "Preview-based system-inversion for output-tracking : theory & application /." Thesis, Connect to this title online; UW restricted, 2003. http://hdl.handle.net/1773/7136.
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Schkoda, Ryan F. "Dynamic inversion of underactuated systems via squaring transformation matrix /." Online version of thesis, 2007. http://hdl.handle.net/1850/5282.
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Healy, David. "Fracture prediction and the inversion of fault parameters using elastic dislocation theory." Thesis, University of Liverpool, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.402306.
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Zbinden, Dominik. "Inversion of 2D Magnetotelluric and Radiomagnetotelluric data with Non-Linear Conjugate Gradient techniques." Thesis, Uppsala universitet, Geofysik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-256900.
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I implemented and tested the method of Non-Linear Conjugate Gradients (NLCG) to invert magnetotelluric (MT) and radiomagnetotelluric (RMT) data in two dimensions. The forward problem and the objective function gradients were computed using finite-difference methods. The NLCG algorithm was applied to three field data sets to test the performance of the code. It was then compared to the inversion techniques of Occam and damped Occam considering the quality of the output resistivity models and the computation times. The implemented code was further investigated by testing two line search techniques to reduce the objective function along a given search direction. The first line search procedure was constrained to the first Wolfe condition, leading to a rather inexact line search. The second, more thorough line search, was additionally constrained to the second Wolfe condition. Three preconditioners were applied to the NLCG algorithm and their performance was analysed. The first preconditioner was set to the diagonal of the approximate Hessian matrix and updated every 20-th iteration. Preconditioners two and three were updated with the Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm using the identity matrix and the diagonal of the approximate Hessian matrix as start preconditioners, respectively. The tests showed that the method of NLCG is more efficient pertaining to computation times compared to the Gauss-Newton (GN) based techniques (Occam and damped Occam). For the two smaller data sets that were inverted, the NLCG inversion was two to four times faster than Occam and damped Occam. For the larger data set, the NLCG inversion converged more than one order of magnitude faster than the GN based inversion techniques. This is because GN methods require to evaluate the entire sensitivity matrix to update the model, whereas NLCG only needs to compute a matrix-vector product of the Jacobian. Moreover, expensive operations such as matrix products and direct inversions of linearised systems are avoided by NLCG. A limitation of the NLCG algorithm is that it is prone to converge to local minima due to the fixed Lagrange multiplier that is used in the penalty function. Occam inversion, which determines the optimal Lagrange multiplier as part of the inversion, did not show such problems. The line search tests of the NLCG algorithm showed that an inexact line search yields higher convergence per CPU time than a more exact line search. In accordance to previous studies, preconditioning accelerated the convergence of the NLCG algorithm considerably. The preconditioners updated with the BFGS algorithm achieved highest convergence. Choosing the identity matrix as a start preconditioner led to fast but unstable convergence. The reasons for that could not be determined completely. Taking the diagonal of the approximate Hessian as a start preconditioner instead of the identity matrix led to slower convergence for most of the inversion tests, but convergence could be stabilised. All the tests performed within this project led to a robust implementation of the NLCG algorithm. A default set-up pertaining to line search and preconditioning could be established. However, the NLCG set-up can be adjusted by the user to improve convergence for a specific data set. This makes the algorithm implemented in this thesis more flexible than previously introduced NLCG codes. Preconditioning can certainly still be improved with further tests. Moreover, a future project will be to extend the 2D code to 3D, where NLCG should perform especially well, because the number of model parameters is usually higher in 3D.
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Fu, Shuai. "Inversion probabiliste bayésienne en analyse d'incertitude." Phd thesis, Université Paris Sud - Paris XI, 2012. http://tel.archives-ouvertes.fr/tel-00766341.
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Ce travail de recherche propose une solution aux problèmes inverses probabilistes avec des outils de la statistique bayésienne. Le problème inverse considéré est d'estimer la distribution d'une variable aléatoire non observée X a partir d'observations bruitées Y suivant un modèle physique coûteux H. En général, de tels problèmes inverses sont rencontrés dans le traitement des incertitudes. Le cadre bayésien nous permet de prendre en compte les connaissances préalables d'experts surtout avec peu de données disponibles. Un algorithme de Metropolis-Hastings-within-Gibbs est proposé pour approcher la distribution a posteriori des paramètres de X avec un processus d'augmentation des données. A cause d'un nombre élevé d'appels, la fonction coûteuse H est remplacée par un émulateur de krigeage (méta-modèle) H chapeau. Cette approche implique plusieurs erreurs de nature différente et, dans ce travail, nous nous attachons a estimer et réduire l'impact de ces erreurs. Le critère DAC a été proposé pour évaluer la pertinence du plan d'expérience (design) et le choix de la loi a priori, en tenant compte des observations. Une autre contribution est la construction du design adaptatif adapté a notre objectif particulier dans le cadre bayésien. La principale méthodologie présentée dans ce travail a été appliquée a un cas d' étude d'ingénierie hydraulique.
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Vigo, Eugenio M. "Copular inversion and non-subject agreement." Doctoral thesis, Universitat Pompeu Fabra, 2016. http://hdl.handle.net/10803/397778.
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In this thesis I propose an explanation for the facts of copular inversion in Spanish, Catalan, and other Romance languages, as well as in German. Copular inversion is a phenomenon found in some languages, in which, at least superficially, the copula may be found agreeing with the postverbal DP instead of the preverbal DP. At first sight it appears that the agreeing postverbal DP is the subject of the sentence, but in this work I provide evidence that this is not the case: the agreeing postverbal DP is, in fact, the complement of the copula. This yields a singular case of non-subject agreement in Spanish, Romance and the rest of copular inversion languages that is not found in the rest of the grammar of these very same languages (e.g. they do not ever show object-agreement in transitive sentences). This requires an explanation that is integrated with the rest of the grammars of the languages. I claim that coreference is the driving force behind the presence of copular inversion: in copular inversion languages, all verbs actually seek agreement with it and all those grammatical functions that are coreferential with the subject. In intransitive and transitive sentences, the only possible candidate is the subject, but in copular sentences the complement is usually coreferential with the subject. The choice of the agreeing function among the possible candidates is decided with respect to a Person-Number Hierarchy: the copula will always agree with the function that has the most marked person and number agreement features with respect to it. This requires challenging the standard view of LFG by which the lexical entries of verbs determine the person and number features of the subject: the solution requires accepting that the person and number features of the verb must be represented in a function-independent “bundle” that is unified with the right grammatical function according to syntactic well-formedness constraints in an OT setting. Additionally to explain the facts of copular inversion languages, the proposed OT-LFG hypothesis predicts why other languages do not have copular inversion. Moreover, the proposed hypothesis can easily be extended to other phenomena of non-subject agreement, e.g. Catalan cleft sentences, Icelandic non-subject agreement in “quirky case” constructions, English locative inversion and agreement phenomena in the Dargwa family of languages.En la presente tesis doctoral expongo una explicación para la inversión copulativa –presente en la mayoría de las lenguas romances como también en alemán–. Este fenómeno consiste, superficialmente, en que la cópula concuerda con el sintagma nominal posverbal en vez del preverbal. A primera vista, esto puede parecer simplemente que el sujeto se encuentra en posición posverbal, pero la evidencia que se presenta en este trabajo demuestra que ese sintagma posverbal no es el sujeto, sino el complemento del verbo. Por tanto, esta es una construcción singular en la que un verbo concuerda con un no-sujeto, con la misma morfología empleada para la concordancia con el sujeto, cosa absolutamente inusitada para la gramática de las lenguas analizadas –que carecen de cualquier tipo de concordancia verbo-objeto, por ejemplo–. Así pues, defiendo que la inversión copulativa es consecuencia del hecho de que la concordancia en estas lenguas es, en realidad, entre el verbo y alguna función gramatical que sea correferente con el sujeto, incluido el propio sujeto. Naturalmente, solo las oraciones copulativas poseen dos funciones correferentes con el sujeto –el sujeto y el complemento–, debido al significado de la cópula; en otros tipos de oraciones, la única función disponible es el sujeto, por lo cual el verbo solo puede concordar con este. La función con la cual se concuerda será aquella correferente con el sujeto cuyos rasgos de persona y número sean los más marcados según una Jerarquía de Persona y Número. Para ello, es absolutamente necesario abandonar la premisa de la Gramática Léxico-Funcional por la cual la concordancia del verbo se establece en su entrada léxica como una determinación de los rasgos de las funciones gramaticales concordantes. Aquí defiendo que los verbos simplemente determinan sus rasgos de concordancia, independientes de toda función gramatical, y que estos son unificados con los rasgos de una u otra función o funciones según restricciones formales de la gramática que, en este trabajo, se estipulan en un marco teórico inspirado en la Teoría de la Optimidad. Esto me permite explicar por qué existen lenguas como el inglés que carecen de dicha construcción e, incluso, explicar fácilmente otros fenómenos de concordancia verbal con no-sujetos en otras lenguas, como, por ejemplo, en islandés en construcciones de sujeto en caso oblicuo, en la inversión locativa presente en inglés y en general en las lenguas dargwa.
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Bhattarai, Bishal. "Ab initio Structure Inversion for Amorphous Materials." Ohio University / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1537349044469989.
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Wu, Ying. "Inversion-based feedforward-feedback control theory and implementation to high-speed atomic force microscope imaging /." [Ames, Iowa : Iowa State University], 2009. 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:3396982.
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Downs, M. L. N. "Mobius inversion of some classical groups and their application to the enumeration of regular hypermaps." Thesis, University of Southampton, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.381232.
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Kozlovskaya, E. (Elena). "Theory and application of joint interpretation of multimethod geophysical data." Doctoral thesis, University of Oulu, 2001. http://urn.fi/urn:isbn:9514259602.
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Abstract
This work is devoted to the theory of joint interpretation of multimethod geophysical data and its
application to the solution of real geophysical inverse problems. The targets of such joint interpretation
can be geological bodies with an established dependence between various physical properties that cause
anomalies in several geophysical fields (geophysical multiresponse). The establishing of the relationship
connecting the various physical properties is therefore a necessary first step in any joint interpretation
procedure. Bodies for which the established relationship between physical properties is violated
(single-response bodies) can be targets of separate interpretations. The probabilistic (Bayesian) approach
provides the necessary formalism for addressing the problem of the joint inversion of multimethod
geophysical data, which can be non-linear and have a non-unique solution. Analysis of the lower limit of
resolution of the non-linear problem of joint inversion using the definition of e-entropy demonstrates that
joint inversion of multimethod geophysical data can reduce non-uniqueness in real geophysical inverse
problems. The question can be formulated as a multiobjective optimisation problem (MOP), enabling the
numerical methods of this theory to be employed for the purpose of geophysical data inversion and for
developing computer algorithms capable of solving highly non-linear problems. An example of such a problem
is magnetotelluric impedance tensor inversion with the aim of obtaining a 3-D resistivity distribution. An
additional area of application for multiobjective optimisation can be the combination of various types of
uncertain information (probabilistic and non-probabilistic) in a common inversion scheme applicable to
geophysical inverse problems. It is demonstrated how the relationship between seismic velocity and density
can be used to construct an algorithm for the joint interpretation of gravity and seismic wide-angle
reflection and refraction data. The relationship between the elastic and electrical properties of rocks,
which is a necessary condition for the joint inversion of data obtained by seismic and electromagnetic
methods, can be established for solid- liquid rock mixtures using theoretical modelling of the elastic and
electrical properties of rocks with a fractal microstructure and from analyses of petrophysical data and
borehole log data.
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Horn, Alan James. "The enigma of the inversion : a study in the dialectics of Hegel and Marx." Thesis, University of Glasgow, 2003. http://theses.gla.ac.uk/1776/.
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The thesis is a contribution to the understanding of the relationship of the dialectical thought and method of G. W. F. Hegel and K. Marx. The aim of the thesis is to ascertain what the relation and the difference between the contrary forms, of the idealist and the materialist dialectic, actually is. The thesis consequently attempts to make sense of Marx’s view that his application of the dialectical method was not only different from but also the “direct opposite” of his idealist predecessor. This theme, itself the source for the enigmatic nature of the inversion, is developed by ascertaining some of the core elements that lie behind and underpin Marx’s own comment; that the rational kernel of Hegel’s mystical form of dialectic could be discovered if it was “turned right side up again”. The thesis also explored the relationship between the early Marx’s critique of Hegel, contained in the 1844 Paris Manuscripts, with the later Marx’s comments on his view of the relation of his dialectic to Hegel’s. As such, the thesis argues that there is both a continuity and a development in Marx’s critical attitude to Hegel’s dialectical thought. The core elements of the rational kernel of Hegel’s dialectic for Marx lies, as the thesis will argue, in the Hegelian account of the general form of working of the dialectic, and in Hegel’s explication of the laws of dialectics. The thesis thus explore the intimate relation of these two interconnected themes from the point of view of Hegel’s systematic idealism, and in Marx’s materialist application of these rational elements to his critique of political economy. This involves endeavouring to elucidate, both the nature of a dialectical account of contradiction, and the related explanation of nomological activity or law from a dialectical perspective. The thesis also attempts to explore the fundamental contrast of the materialist from the idealist elucidation of these core elements.
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Hennenfent, Gilles, Felix J. Herrmann, and Ramesh Neelamani. "Seismic deconvolution revisited with curvelet frames." European Association of Geoscientists & Engineers, 2005. http://hdl.handle.net/2429/503.
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We propose an efficient iterative curvelet-regularized deconvolution algorithm that exploits continuity along reflectors in seismic images. Curvelets are a new multiscale transform that provides sparse representations for images (such as seismic images) that comprise smooth objects separated by piece-wise smooth discontinuities. Our technique combines conjugate gradient-based convolution operator inversion with noise regularization that is performed using non-linear curvelet coefficient shrinkage (thresholding). The shrinkage operation leverages the sparsity of curvelets representations. Simulations demonstrate that our algorithm provides improved resolution compared to the traditional Wiener-based deconvolution approach.
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Jordan, Michael. "JI-3D - a new approach to high resolution regional seismic tomography theory and applications /." Doctoral thesis, [S.l.] : [s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=96850681X.
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Mullen, Jon. "FILTERED-DYNAMIC-INVERSION CONTROL FOR FIXED-WING UNMANNED AERIAL SYSTEMS." UKnowledge, 2014. http://uknowledge.uky.edu/me_etds/45.
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Instrumented umanned aerial vehicles represent a new way of measuring turbulence in the atmospheric boundary layer. However, autonomous measurements require control methods with disturbance-rejection and altitude command-following capabilities. Filtered dynamic inversion is a control method with desirable disturbance-rejection and command-following properties, and this controller requires limited model information. We implement filtered dynamic inversion as the pitch controller in an altitude-hold autopilot. We design and numerically simulate the continuous-time and discrete-time filtered-dynamic-inversion controllers with anti-windup on a nonlinear aircraft model. Finally, we present results from a flight experiment comparing the filtered-dynamic-inversion controller to a classical proportional-integral controller. The experimental results show that the filtered-dynamic-inversion controller performs better than a proportional-integral controller at certain values of the parameter.
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Xu, Weijun. "Inverting the signature of a path." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:954ff1e3-9162-456a-91a3-39734854cde2.
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This thesis consists of two parts. The first part (Chapters 2-4) focuses on the problem of inverting the signature of a path of bounded variation, and we present three results here. First, we give an explicit inversion formula for any axis path in terms of its signature. Second, we show that for relatively smooth paths, the derivative at the end point can be approximated arbitrarily closely by its signature sequence, and we provide explicit error estimates. As an application, we give an effective inversion procedure for piecewise linear paths. Finally, we prove a uniform estimate for the signatures of paths of bounded variations, and obtain a reconstruction theorem via that uniform estimate. Although this general reconstruction theorem is not computationally efficient, the techniques involved in deriving the uniform estimate are useful in other situations, and we also give an application in the case of expected signatures for Brownian motion. The second part (Chapter 5) deals with rough paths. After introducing proper backgrounds, we extend the uniform estimate above to the context of rough paths, and show how it can lead to simple proofs of distance bounds for Gaussian iterated integrals.
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Aldaoudeyeh, Al Motasem. "Weak Power Grid Analysis for Renewable Energy Sources Integration." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/31536.
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Weakness analysis based on grid strength assessment is useful for identifying potential weak grid issues. However, when taking into account the impact of the interactions among Renewable Energy Sources (RESs), the weakness analysis becomes computationally challenging. Different combinations of PointsofInterconnections (POIs) of RESs may have different impacts on grid strength at each POI. Due to the combination nature, such weakness analysis may be time-consuming when identifying the weakest combination of POIs from a large number of potential candidate locations in realistic power grids. This dissertation addresses the topic of determination of the weakest RESs combinations. Based on impedance ratios as a criterion, the dissertation shows that the impacts of impedance ratios magnitudes and angles are ?quasi-mutually exclusive?. Such a concept is then used to reduce the computational burden with a fast screening algorithm.
To further understand the impact of network components on grid strength, vector-based interaction analysis is developed based on the concepts of operational transfer impedances and operational interaction operators. In particular, this dissertation shows how mathematical models of interaction of multiple RESs can be simplified by replacing them with equivalent impedances, allowing us to simplify the mathematical expressions that quantify interactions among RESs. The conclusions and concepts established based on simplified models are statistically tested for their applicability to the generalized interaction model. The result would be a more simplified mathematical representation of interaction among RESs.
Finally, a new technique is presented to efficiently update the Bus Impedance Matrix (Zbus) following changes in the series impedance of a branch. Conventionally, such update requires redundant recalculations, which involve matrix inversion operations (i.e., inverting the Bus Admittance Matrix, Ybus) and thus cause high computational burden because of potential matrix ill-conditioning, especially for largescale power grids. This dissertation overcomes these shortcomings by deriving an analytical expression for changes in Zbus in terms of its old elements and the variation of the impedance of a given branch. Hence, the computation overhead is comparatively small, and no issues arise due to the new Ybus being ill-conditioned. Such contribution helps facilitate real-time applications of methods that rely on Zbus.
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Da, silva Antonio. "Theoretical determination of optical properties for sapphire doped with titanium from its microscopy and analysis of its capabilities for laser without population inversion." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX075/document.
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Cet exposé est scindé en deux grandes parties. Dans la première, nous estimons des constantes photo-physiques du saphir dopé au titane à partir d'un modèle analytique simple exploitant une théorie de Huang-Rhys pour la détermination du profil spectral des bandes simples et une hypothèse réaliste de superposition de ces dernières. Nous déterminons une formule pour l'indice de réfraction total du Ti:saphir en fonction de la concentration de dopant. Dans une seconde partie, nous évaluons, selon la vérification d'un concept, la capacité de laser sana inversion de populations pour un cristal dopé possédant une basse symétrie. Nous appuyons notre démonstration en établissant une condition de seuil généralisée d'effet laser. Ce concept pourrait être une rupture technologique dans le domaine des grands cristaux dopés et n'a pas encore été investigué par la communautéThis presentation is split into two main parts. In the first, we estimate photo-physical constants of titanium doped sapphire from a simple analytical model using a Huang-Rhys theory for the determination of the spectral profile of simple bands and from a realistic hypothesis of superposition of the latter. We define a formula for the total refractive index of Ti:sapphire as a function of dopant concentration. In a second part, we evaluate, according to the verification of a concept, the laser capability without population inversion for a doped crystal with low symmetry. We support our demonstration by establishing a generalized laser threshold condition. This concept would be a technological breakthrough in the field of large doped crystals and has not yet been investigated by the community
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Tsareva, Olga. "Variabilité temporelle du champ magnétique terrestre et son influence sur l'environnement spatial proche." Thesis, Toulouse 3, 2020. http://www.theses.fr/2020TOU30122.
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Le champ magnétique terrestre connaît une forte variabilité temporelle avec des périodes caractéristiques aussi courtes que la dizaine de secondes (sous-orages magnétosphériques responsables du déclenchement des aurores polaires) et aussi longues que le million d'années (inversions de la polarité nord-sud). Ses variations temporelles, bien que d'origine et de caractéristiques très différentes, affectent la dynamique de l'environnement spatial proche de la Terre : précipitation de particules dans la haute atmosphère, modification des flux de particules cosmiques, échappement atmosphérique. La première partie de cette thèse est dédiée au développement d'une nouvelle théorie cinétique des instabilités dans la queue magnétosphérique qui pourrait expliquer l'origine des sous-orages. En partant d'une théorie connue des instabilités de dérive liées à la présence d'un gradient de pression dans la queue magnétosphérique, le modèle proposé dans cette these inclut le mouvement de rebond des électrons piégés dans le champ géomagnétique qui peuvent entrer en résonance avec les modes de dérive (drift-Alfvén instability) si le gradient de densité dans la queue devient important. La prise en compte de ce mouvement de rebond augmente significativement le taux de croissance de cette instabilité universelle. Pour tenter de valider ce nouveau modèle, un exemple d'observation aurorale par la mission THEMIS (3 février 2008) a été analysé. Cet événement a été choisi car il correspond à un arc auroral isolé observé à la fois par les caméras All-sky situées au sol et par les satellites THEMIS orbitant à 10 RE. Cette activation aurorale semble bien avoir été déclenchée par une soudaine compression de la queue magnétosphérique vers 10 RE augmentant sensiblement le gradient de pression et provoquant des fluctuations importantes du champ magnétique. Les ordres de grandeur de la période et du taux de croissance de ces oscillations sont compatibles avec les courbes de dispersion déduites du modèle théorique. La deuxième partie de la thèse étudie l'influence du renversement des polarités du champ magnétique sur l'environnement radiatif de la Terre. En particulier, nous avons calculé les variations du flux de protons cosmiques lors d'une inversion géomagnétique pour déduire les doses de rayonnement auxquelles la population humaine et les astronautes pourraient être exposés. [...]The Earth's magnetic field undergoes strong temporal variabilities with characteristic periods as short as ten seconds (magnetospheric substorms triggering the polar aurora) and as long as a million years (geomagnetic reversals). Its temporal variations, although of very different origin and characteristics, affect the dynamics of the near-Earth space environment.The first part of this thesis is dedicated to the development of a new kinetic theory of instabilities in the magnetospheric tail which could explain the origin of substorms. Starting from a known theory of drift instabilities linked to the presence of a pressure gradient in the magnetotail, the proposed model includes trapped bouncing electrons which can enter into resonance with drift Alfvén instability modes if the density gradient in the tail becomes large. Taking this the bouncing motion into account significantly increases the growth rate of this universal instability. To try to validate this new model, an example of an auroral observation by the THEMIS mission (February 3, 2008) was analyzed. This event was chosen because it corresponds to an isolated auroral arc observed both by the All-sky cameras located on the ground and by the THEMIS satellites orbiting at 10 RE. This auroral activation seems to have been triggered by a sudden compression of the magnetospheric tail towards 10 RE significantly increasing the pressure gradient and causing significant fluctuations in the magnetic field. The orders of magnitude of the period and the growth rate of these oscillations are compatible with the dispersion curves deduced from the theoretical model.Second part of the thesis is devoted to changes in the radiation situation on Earth, the radiation belts and the terrestrial atmosphere during Earth's magnetic field reversal. We calculated the variations in galactic cosmic proton flux during a geomagnetic reversal to infer the radiation doses to which human population and astronauts could be exposed. The radiation background should increase by a factor of about three during the solar minimum period, and the elevated radiation regions should be redistributed and their areas will apparently increase due to the dipole field decrease, such radiation doses are not dangerous for humans and other living creatures. At the same time, for astronauts aboard the ISS orbiting at 400 km above the ground, during a reversal period a 14-fold radiation increase can be dangerous. Undoubtedly, in this case, a correction of the orbits of space vehicles would be required. Classical Störmer theory was generalized to the case of an axisymmetric superposition of dipole and quadrupole fields. [...]
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Arroyo, Negrete Elkin Rafael. "Continuous reservoir model updating using an ensemble Kalman filter with a streamline-based covariance localization." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4859.
Full textAbstract:
This work presents a new approach that combines the comprehensive capabilities
of the ensemble Kalman filter (EnKF) and the flow path information from streamlines to
eliminate and/or reduce some of the problems and limitations of the use of the EnKF for
history matching reservoir models. The recent use of the EnKF for data assimilation and
assessment of uncertainties in future forecasts in reservoir engineering seems to be
promising. EnKF provides ways of incorporating any type of production data or time
lapse seismic information in an efficient way. However, the use of the EnKF in history
matching comes with its shares of challenges and concerns. The overshooting of
parameters leading to loss of geologic realism, possible increase in the material balance
errors of the updated phase(s), and limitations associated with non-Gaussian permeability
distribution are some of the most critical problems of the EnKF. The use of larger
ensemble size may mitigate some of these problems but are prohibitively expensive in
practice.
We present a streamline-based conditioning technique that can be implemented
with the EnKF to eliminate or reduce the magnitude of these problems, allowing for the
use of a reduced ensemble size, thereby leading to significant savings in time during field
scale implementation. Our approach involves no extra computational cost and is easy to
implement. Additionally, the final history matched model tends to preserve most of the
geological features of the initial geologic model.
A quick look at the procedure is provided that enables the implementation of this
approach into the current EnKF implementations. Our procedure uses the streamline path
information to condition the covariance matrix in the Kalman Update. We demonstrate
the power and utility of our approach with synthetic examples and a field case. Our result shows that using the conditioned technique presented in this thesis, the
overshooting/undershooting problems disappears and the limitation to work with non-
Gaussian distribution is reduced. Finally, an analysis of the scalability in a parallel
implementation of our computer code is given.
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Al, Kalanee T. "Étude du noyau d'9He via la réaction de transfert d(8He, p) à 15.4 MeV/nucléon." Phd thesis, Université de Caen, 2010. http://tel.archives-ouvertes.fr/tel-00557105.
Full textAbstract:
L'étude des noyaux légers riches en neutrons à la limite de la stabilité et au-delà suscite un intérêt marqué depuis quelques années car elle offre des tests approfondis de notre compréhension de la structure nucléaire. Expérimentalement, la disponibilité récente de faisceaux radioactifs avec des intensités suffisantes et le développement de nouveaux systèmes de détection de grande acceptance ont permis de sonder la structure de ces noyaux. Cette thèse porte sur l'étude de la structure de l'9He, système N = 7 non lié, via la réaction de transfert d'un neutron d(8He, p)9He avec l'aide d'un faisceau SPIRAL1. L'objectif principal de l'expérience était de clarifier la structure des états à basse énergie d'excitation de l'9He, en particulier l'inversion de parité possible de l'état fondamental. L'expérience a été une des premières à utiliser le nouvel ensemble de détection MUST2. Les statistiques relativement faibles dans la région du seuil d'émission de neutron et les divers fonds physiques, ne permettent pas de conclusion définitive concernant la nature de l'état de plus basse énergie. Des états à des énergies d'excitation plus élevées ont été identifiés. Une comparaison entre les distributions angulaires pour chacune des résonances avec des calculs DWBA et CRC a été effectuée. Les facteurs spectroscopiques ont été estimées pour chaque spin possible.
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Li, Ka Lok. "Location and Relocation of Seismic Sources." Doctoral thesis, Uppsala universitet, Geofysik, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-327038.
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This dissertation is a comprehensive summary of four papers on the development and application of new strategies for locating tremor and relocating events in earthquake catalogs. In the first paper, two new strategies for relocating events in a catalog are introduced. The seismicity pattern of an earthquake catalog is often used to delineate seismically active faults. However, the delineation is often hindered by the diffuseness of earthquake locations in the catalog. To reduce the diffuseness and simplify the seismicity pattern, a relocation and a collapsing method are developed and applied. The relocation method uses the catalog event density as an a priori constraint for relocations in a Bayesian inversion. The catalog event density is expressed in terms of the combined probability distribution of all events in the catalog. The collapsing method uses the same catalog density as an attractor for focusing the seismicity in an iterative scheme. These two strategies are applied to an aftershock sequence after a pair of earthquakes which occurred in southwest Iceland, 2008. The seismicity pattern is simplified by application of the methods and the faults of the mainshocks are delineated by the reworked catalog. In the second paper, the spatial distribution of seismicity of the Hengill region, southwest Iceland is analyzed. The relocation and collapsing methods developed in the first paper and a non-linear relocation strategy using empirical traveltime tables are used to process a catalog collected by the Icelandic Meteorological Office. The reworked catalog reproduces details of the spatial distribution of seismicity that independently emerges from relative relocations of a small subset of the catalog events. The processed catalog is then used to estimate the depth to the brittle-ductile transition. The estimates show that in general the northern part of the area, dominated by volcanic processes, has a shallower depth than the southern part, where tectonic deformation predominates. In the third and the fourth papers, two back-projection methods using inter-station cross correlations are proposed for locating tremor sources. For the first method, double correlations, defined as the cross correlations of correlations from two station pairs sharing a common reference station, are back projected. For the second method, the products of correlation envelopes from a group of stations sharing a common reference station are back projected. Back projecting these combinations of correlations, instead of single correlations, suppresses random noise and reduces the strong geometrical signature caused by the station configuration. These two methods are tested with volcanic tremor at Katla volcano, Iceland. The inferred source locations agree with surface observations related to volcanic events which occurred during the tremor period.
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Ferreira, Ivana Kátia de Souza. "Os verbos inacusativos e a inversão do sujeito em sentenças declarativas do português brasileiro." Pontifícia Universidade Católica do Rio Grande do Sul, 2011. http://hdl.handle.net/10923/4037.
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Previous issue date: 2011This academic work deals with the unaccusative verbs and the free inversion of the subject in declarative sentences in Brazilian Portuguese (BP). This study is based on a bibliographic review, in the light of the Generative Syntax, under the Government-Binding (GB) Theory. It is proposed by Chomsky (1981), in accordance with the Principles and Parameters model. Firstly, a summary of the fundamental topics (Lexicon, Verb Subcategorization, Case Theory, θ-Theory, Argument Structure) within the GB is made, not to mention that these topics are absolutely related to the main subject. Thereafter, the unaccusative verbs (monoargumental) and their particularity are presented. A comparison is made between the unaccusative and the inergative verbs. Although they are both monoargumental verbs, they have different syntactic structures from each other. Their Dstructures show such differences.The unaccusative verbs subcategorize a Determiner Phrase (DP) complement (in the object place), while the inergative ones select an external argument. When the inversion of the DP subject occurs, it remains in its original position within the Verb Phrase (VP). According to relevant authors (Pontes, 1986; Kato, 2000; Menuzzi, 2003) to this work, the unaccusative verbs are compatible with the V(erb)S(ubject) order in BP. The occurance of two kinds of agreement is verified in the sentences when the DP subject occupies the post-verbal position. When the verb agrees with the post-verbal DP subject ([pro] Chegaram as visitas), the agreement results from a chain between the post-verbal DP subject and the null expletive pro. When the verb remains in the 3rd person of singular ([pro] Chegou as visitas), it reveals that the agreement is with the pre-verbal null expletive pro, singular according to Mioto et al. (2007). The agreement with the pre-verbal expletive is likewise in French. However in French the pre-verbal expletive is not null; it is the lexical one il.
Este trabalho trata sobre os verbos inacusativos e a livre inversão do sujeito em sentenças declarativas do português brasileiro (PB). É um estudo, com base em revisão bibliográfica, à luz da Sintaxe Gerativa, sob a perspectiva da Teoria da Regência e da Ligação (TRL), proposta por Chomsky (1981), em conformidade com o modelo Princípios e Parâmetros. Primeiramente, é feito um apanhado de tópicos fundamentais (Léxico, Subcategorização Verbal, Teoria do Caso, Teoria Theta, Estrutura de Argumentos) para a TRL, bem como relacionados ao assunto a ser discutido. Após essa exposição, são apresentados os verbos inacusativos (monoargumentais) e as suas especificidades. É feita uma comparação entre os verbos inacusativos e os inergativos, tendo em vista serem ambos monoargumentais. Apesar disso, apresentam estruturas sintáticas completamente distintas. Suas estruturas-D mostram tais diferenças. Os inacusativos subcategorizam um Determiner Phrase (DP) complemento (posição de objeto).Os inergativos selecionam somente argumento externo. Quando ocorre a inversão do DP sujeito, este permanece em sua posição de base, dentro do V(erb)P(hrase). De acordo com autores relevantes (Pontes, 1986; Kato, 2000; Menuzzi, 2003) para este trabalho, os verbos inacusativos são compatíveis com a ordem V(erbo)S(ujeito) no PB. Nas sentenças VS com inacusativos, são verificadas duas possibilidades de concordância. Quando o verbo concorda com o DP sujeito pós-verbal ([pro] Chegaram as visitas), a concordância resulta da cadeia entre o DP sujeito pós-verbal e o expletivo nulo pro pré-verbal. Quando o verbo permanece na 3ª pessoa do singular ([pro] Chegou as visitas), a concordância é realizada com o expletivo nulo pro pré-verbal, que, de acordo com Mioto et al. (2007), é singular. A concordância com o expletivo pré-verbal é como no francês, por exemplo. Porém, no francês, o expletivo pré-verbal não é nulo, é lexical (Il).
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Wong, Vivian Lola. "MACMAHON'S MASTER THEOREM AND INFINITE DIMENSIONAL MATRIX INVERSION." Master's thesis, University of Central Florida, 2004. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4443.
Full textAbstract:
MacMahon's Master Theorem is an important result in the theory of algebraic combinatorics. It gives a precise connection between coefficients of certain power series defined by linear relations. We give a complete proof of MacMahon's Master Theorem based on MacMahon's original 1960 proof. We also study a specific infinite dimensional matrix inverse due to C. Krattenthaler.M.S.
Department of Mathematics
Arts and Sciences
Mathematics
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Saers, Markus. "Translation as Linear Transduction : Models and Algorithms for Efficient Learning in Statistical Machine Translation." Doctoral thesis, Uppsala universitet, Institutionen för lingvistik och filologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-135704.
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Automatic translation has seen tremendous progress in recent years, mainly thanks to statistical methods applied to large parallel corpora. Transductions represent a principled approach to modeling translation, but existing transduction classes are either not expressive enough to capture structural regularities between natural languages or too complex to support efficient statistical induction on a large scale. A common approach is to severely prune search over a relatively unrestricted space of transduction grammars. These restrictions are often applied at different stages in a pipeline, with the obvious drawback of committing to irrevocable decisions that should not have been made. In this thesis we will instead restrict the space of transduction grammars to a space that is less expressive, but can be efficiently searched. First, the class of linear transductions is defined and characterized. They are generated by linear transduction grammars, which represent the natural bilingual case of linear grammars, as well as the natural linear case of inversion transduction grammars (and higher order syntax-directed transduction grammars). They are recognized by zipper finite-state transducers, which are equivalent to finite-state automata with four tapes. By allowing this extra dimensionality, linear transductions can represent alignments that finite-state transductions cannot, and by keeping the mechanism free of auxiliary storage, they become much more efficient than inversion transductions. Secondly, we present an algorithm for parsing with linear transduction grammars that allows pruning. The pruning scheme imposes no restrictions a priori, but guides the search to potentially interesting parts of the search space in an informed and dynamic way. Being able to parse efficiently allows learning of stochastic linear transduction grammars through expectation maximization. All the above work would be for naught if linear transductions were too poor a reflection of the actual transduction between natural languages. We test this empirically by building systems based on the alignments imposed by the learned grammars. The conclusion is that stochastic linear inversion transduction grammars learned from observed data stand up well to the state of the art.
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Narasimha, Reddy Vaka. "Comparison and Optimization of Insonation Strategies for Contrast Enhanced Ultrasound Imaging." Thesis, Linköpings universitet, Biomedicinsk instrumentteknik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-76646.
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Evolution of vulnerable carotid plaques are crucial reason for cerebral ischemic strokes and identifying them in the early stage can become very important in avoiding the risk of stroke. In order to improve the identification and quantification accuracy of infancy plaques better visualization techniques are needed. Improving the visualization and quantification of neovascularization in carotid plaque using contrast enhanced ultrasound imaging still remains a challenging task. In this thesis work, three optimization techniques are proposed, which showed an improvement in the sensitivity of contrast agents when compared to the conventional clinical settings and insonation strategies. They are as follows:1) Insonation at harmonic specific (2nd harmonic) resonance frequency instead of resonance frequency based on maximum energy absorption provides enhanced nonlinear contribution.2) At high frequency ultrasound imaging, shorter pulse length will provide improved harmonic signal content when compared to longer pulse lengths. Applying this concept to multi- pulse sequencing (Pulse Inversion and Cadence contrast pulse sequencing) resulted in increased magnitude of the remaining harmonic signal after pulse summations.3) Peak negative pressure optimization of Pulse Inversion and Cadence contrast pulse sequencing was showed to further enhance the nonlinear content of the backscattered signal from contrast microbubbles without increasing the safety limits, defined by the mechanical index.The results presented in this thesis are based on computational modeling (Bubblesim software) and as a future continuation we plan to verify the simulation results with vitro studies.
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Souza, Landolfo Andrade de. "O ônus da prova na ação civil pública: hipóteses de flexibilização." Pontifícia Universidade Católica de São Paulo, 2013. https://tede2.pucsp.br/handle/handle/6270.
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Previous issue date: 2013-10-24There is no doubt that the modern civil procedure must be updated to cope with the substantive law needs and the new contemporary society dynamics. Likewise, such changes dispense legislative modifications, which often take a long time to be made. Thus, it s necessary to pursue the procedure s improvement by a more appropriate managing of the procedural techniques available for the judge, in the light of the constitutional guarantees. The rule for the burden of proof is within this perspective: it s one of the matters to which the doctrine devotes its attention in order to make the indispensable transformations in the procedural system to bring it closer to substantive law s reality. To this end, this work searched to examine how the burden of proof operates in the class actions, studying the reasons that authorize its change, since such possibility beyond the realm of consumer law - may correspond to a significant condition of effective protection of collective interests. For that purpose, one has used law doctrine, case law and deductive, inductive and analogical methods. The Federal Constitution and federal rules related to the burden of proof dogma and the collective interests protection have also been examined. The research has been split in for main parts. Firstly, some relevant aspects of the collective procedure have been studied. Then, the structural elements of the burden of proof have been analysed. The third part was dedicated to the conceptual elements, as well as the fundaments of applicability, including de lege lata, of the dynamic burden of proof theory in Brazilian law were outlined. In the fourth part, it has been demonstrated that the hipotheses that allow the flexibility of the general criteria for the distribution of the proof burdens are consistent with one of the most relevant preoccupations of procedural law jurists: the search for more effectiveness in the substantive field by the procedural technique refinement
Não há dúvidas de que o processo civil moderno deve atualizar-se para fazer frente às necessidades do direito material e da nova dinâmica da sociedade contemporânea. Tampouco se duvida que esta mudança prescinde de alterações legislativas, pois estas, muitas vezes, demoram a ocorrer. Impõe-se, então, buscar aprimorar o processo com o manejo mais adequado das técnicas processuais postas à disposição do juiz, à luz das garantias constitucionais. A regra sobre o ônus da prova se insere nesta perspectiva: constitui ela um dos pontos em que se debruça a doutrina para imprimir necessárias alterações no sistema processual, tornando-o mais próximo à realidade do direito material. Nesse propósito, este trabalho buscou apreciar como se comporta a regra do ônus da prova nas ações civis públicas, avaliando as razões que autorizariam a sua modificação, já que esta possibilidade para além dos campos do direito do consumidor pode importar significativa condição para a efetiva tutela dos interesses coletivos. Para tanto, valeu-se do estudo da doutrina e da jurisprudência, bem como se utilizaram os métodos dedutivo, indutivo e analógico. Examinaram-se a Constituição Federal e as normas federais pertinentes ao dogma do ônus da prova, bem como à defesa dos interesses coletivos. A pesquisa foi dividida em quatro partes principais. Na primeira, foram examinados alguns aspectos relevantes do direito processual coletivo. Na segunda, analisaram-se os principais aspectos do instituto do ônus da prova. Na terceira, foram fixados os elementos estruturais, bem como os fundamentos de aplicabilidade, inclusive de lege lata, da teoria do ônus dinâmico da prova no direito brasileiro. Na última parte, demonstrou-se que as hipóteses de flexibilização dos critérios gerais de repartição dos encargos probatórios encontram-se afinadas com uma das principais preocupações dos cultores do direito processual: buscar maior efetividade no plano material por meio do aprimoramento da técnica processual
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Bletery, Quentin. "Analyse probabiliste et multi-données de la source de grands séismes." Thesis, Nice, 2015. http://www.theses.fr/2015NICE4092/document.
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Les séismes sont le résultat de glissements rapides le long de failles actives chargées en contraintes par le mouvement des plaques tectoniques. Il est aujourd'hui établi, au moins pour les grands séismes, que la distribution de ce glissement rapide le long des failles pendant les séismes est hétérogène. Imager la complexité de ces distributions de glissement constitue un enjeu majeur de la sismologie en raison des implications potentielles dans la compréhension de la genèse des séismes et la possibilité associée de mieux anticiper le risque sismique et les tsunamis. Pour améliorer l'imagerie de ces distributions de glissement co-sismique, trois axes peuvent être suivis: augmenter les contraintes sur les modèles en incluant plus d'observations dans les inversions, améliorer la modélisation physique du problème direct et progresser dans le formalisme de résolution du problème inverse. Dans ce travail de thèse, nous explorons ces trois axes à travers l'étude de deux séismes majeurs: les séisme de Tohoku-Oki (Mw 9.0) et de Sumatra-Andaman (Mw 9.1-9.3) survenus en 2011 et 2004, respectivementEarthquakes are the results of rapid slip on active faults loaded in stress by the tectonic plates motion. It is now establish - at least for large earthquakes - that the distribution of this rapid slip along the rupturing faults is heterogeneous. Imaging the complexity of such slip distributions is one the main challenges in seismology because of the potential implications on understanding earthquake genesis and the associated possibility to better anticipate devastating shaking and tsunami. To improve the imaging of such co-seismic slip distributions, three axes may be followed: increase the constraints on the source models by including more observations into the inversions, improve the physical modeling of the forward problem and improve the formalism to solve the inverse problem. In this PhD thesis, we explore these three axes by studying two recent major earthquakes: the Tohoku-Oki (Mw 9.0) and Sumatra-Andaman (Mw 9.1-9.3) earthquakes, which occured in 2011 and 2004 respectively
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Krishnan, Venkateswaran P. "A support theorem and an inversion formula for the geodesic ray transform /." Thesis, Connect to this title online; UW restricted, 2007. http://hdl.handle.net/1773/5804.
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Erlekam, Undine. "Sterically flexible molecules in the gas phase." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2008. http://dx.doi.org/10.18452/15833.
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Für die makroskopischen Eigenschaften und Funktionen biologisch relevanter Materie spielen schwache, intra- und intermolekulare Wechselwirkungen dispersiver und elektrostatischer Natur auf molekularem Niveau eine große Rolle. Um diese schwachen Wechselwirkungen zu untersuchen, können Modellsysteme, isoliert in der Gasphase, herangezogen werden. Benzoldimer, ein schwach gebundener Van der Waals Komplex, kann beispielsweise als Modellsystem für dispersive Wechselwirkungen dienen. In der vorliegenden Arbeit werden die strukturellen Eigenschaften und die (interne) Dynamik des Benzoldimers mit Hilfe spektroskopischer Methoden in den Energiebereichen der Rotationen, Vibrationen und elektronischen Übergänge untersucht und im Kontext der Symmetrie diskutiert. Die in dieser Arbeit vorgestellten Experimente tragen zu einem tieferen Verständnis des Benzoldimers bei, jedoch zeigt das Experiment zur internen Dynamik auch, dass eine ausreichende theoretische Beschreibung des Benzoldimers nach wie vor eine Herausforderung darstellt. Schwingungsübergänge hochsymmetrischer Moleküle sind oft optisch inaktiv, können jedoch mit der hier vorgestellten Methode der Symmetrieerniedrigung durch Komplexierung zugänglich gemacht werden, wie am Beispiel des Benzols demonstriert wird. Außerdem wird ein Mechanismus vorgstellt, der kollisionsinduzierte Konformationsänderungen in einem Molekularstrahl beschreibt. Dieses Modell kann generell für Molekularstrahlexperimente an flexiblen Molekülen hilfreich sein, einerseits um die beobachtete Konformationsverteilung zu verstehen, andererseits um die experimentellen Parameter gezielt zu verändern und somit Konformerpopulationen zu manipulieren. Die in dieser Dissertation vorgestellten spektroskopischen Experimente liefern einerseits molekülspezifische Informationen und ermöglichen andererseits, Modelle, die von allgemeiner Bedeutung sind, zu entwickeln.The macroscopically observable properties and functionalities of biological matter are often determined by weak intra- and intermolecular interactions on the microscopic level. Such weak interactions are for example hydrogen bonding and van der Waals interactions and can be investigated best on isolated model systems in the gas phase. The benzene dimer, for example, is a prototype system to investgate dispersive interactions. The spectroscopic experiments, covering the energy ranges of rotations, vibrations and electronic transitions, presented in this thesis, contribute to a deeper understanding of the benzene dimer. However, from the experiments investigating the internal dynamics it becomes clear that an appropriate theoretical description of the benzene dimer is still a challenge. Vibrational transitions of highly symmetric molecules, as for example of the benzene, are often optically inactive. Here, a method is presented, which exploits symmetry reduction upon complexation and thus allows one to access such modes. Furthermore, a model is proposed describing collision induced conformational interconversion in a molecular beam. This model can be helpful for molecular beam experiments of flexible molecules to understand the observed relative conformational population and to adapt the experimental conditions allowing for the manipulation of the relative conformer abundances. In this thesis, results are presented that allow one on the one hand to deduce molecular specific information and that on the other hand also give a broader insight into phenomena of general importance.
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Shin, Yoonghyun. "Neural Network Based Adaptive Control for Nonlinear Dynamic Regimes." Diss., Georgia Institute of Technology, 2005. http://hdl.handle.net/1853/7577.
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Adaptive control designs using neural networks (NNs) based on dynamic inversion are
investigated for aerospace vehicles which are operated at highly nonlinear dynamic regimes. NNs play a key role as the principal element of adaptation to approximately cancel the effect of inversion error, which subsequently improves robustness to parametric uncertainty and unmodeled dynamics in nonlinear regimes.
An adaptive control scheme previously named composite model reference adaptive control is further developed so that it can be applied to multi-input multi-output output feedback dynamic inversion. It can have adaptive elements in both the dynamic compensator (linear controller) part and/or in the conventional adaptive controller part, also utilizing state estimation information for NN adaptation. This methodology has more flexibility and thus hopefully greater potential than conventional adaptive designs for adaptive flight control in highly nonlinear flight regimes. The stability of the control system is proved through Lyapunov theorems, and validated with simulations.
The control designs in this thesis also include the use of pseudo-control hedging techniques which are introduced to prevent the NNs from attempting to adapt to various actuation nonlinearities such as actuator position and rate saturations. Control allocation is introduced for the case of redundant control effectors including thrust vectoring nozzles. A thorough comparison study of conventional and NN-based adaptive designs for a system under a limit cycle, wing-rock, is included in this research, and the NN-based adaptive control designs demonstrate their performances for two highly maneuverable aerial vehicles, NASA F-15 ACTIVE and FQM-117B unmanned aerial vehicle (UAV), operated under various nonlinearities and uncertainties.
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高木, 直史, and Naofumi Takagi. "A fast algorithm for multiplicative inversion in GF(2m) using normal basis." IEEE, 2001. http://hdl.handle.net/2237/5292.
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Polzer, Jan. "Berechnung der Nulldynamik eines inversen Pendels mit unterschiedlichen mathematischen Theorie." Gerhard-Mercator-Universitaet Duisburg, 2001. http://www.ub.uni-duisburg.de/ETD-db/theses/available/duett-07062001-080306/.
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Die Struktureigenschaft Nulldynamik lässt sich mit unterschiedlichen mathematischen Ansätzen berechnen. In diesem Bericht geht es um die Berechnung der Nulldynamik eines inversen Pendels mit differentialgeometrischen und differentialalgebraischen Methoden. Es findet eine Gegenüberstellung der einzelnen Ergebnisse untereinander sowie eine Gegenüberstellung mit Messungen an einem Prüfstand statt.
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Ladrón, de Guevara Cortés Rogelio. "Techniques For Estimating the Generative Multifactor Model of Returns in a Statistical Approach to the Arbitrage Pricing Theory. Evidence from the Mexican Stock Exchange." Doctoral thesis, Universitat de Barcelona, 2016. http://hdl.handle.net/10803/386545.
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This dissertation focuses on the estimation of the generative multifactor model of returns on equities, under a statistical approach of the Arbitrage Pricing Theory (APT), in the context of the Mexican Stock Exchange. Therefore, this research takes as frameworks two main issues: (i) the multifactor asset pricing models, specially the statistical risk factors approach, and (ii) the dimension reduction or feature extraction techniques: Principal Component Analysis, Factor Analysis, Independent Component Analysis and Non-linear Principal Component Analysis, utilized to extract the underlying systematic risk factors. The models estimated are tested using two methodologies: (i) capability of reproduction of the observed returns using the estimated generative multifactor model, and (ii) results of the econometric contrast of the APT using the extracted systematic risk factors. Finally, a comparative study among techniques is carried on based on their theoretical properties and the empirical results.
According to the above stated and as far as we concerned, this dissertation contributes to financial research by providing empirical evidence of the estimation of the generative multifactor model of returns on equities, extracting statistical underlying risk factors via classic and alternative dimension reduction or feature extraction techniques in the field of finance, in order to test the APT as an asset pricing model, in the context of an emerging financial market such as the Mexican Stock Exchange. In addition, this work presents an unprecedented theoretical and empirical comparative study among Principal Component Analysis, Factor Analysis, Independent Component Analysis and Neural Networks Principal Component Analysis, as techniques to extract systematic risk factors from a stock exchange, analyzing the level of sensitivity of the results in function of the technique carried on. In addition, this dissertation represents a mainly empirical exhaustive study where objective evidence about the Mexican stock market is provided by way of the application of four different techniques for extraction of systematic risk factors, to four datasets, in a test window that ranged from two to nine factors.
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Coronado, Villalobos Carlos Hugo [UNESP]. "Álgebra de Espinores e novos espinores em Física." Universidade Estadual Paulista (UNESP), 2017. http://hdl.handle.net/11449/150120.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
Na presente tese abordaremos quatro tópicos importantes: espinores, covariantes bilineares, classificação de Lounesto e o teorema da inversão. Apresentamos a construção de covariantes bilineares para o espinor Elko e mostraremos a necessidade da deformação dos elementos da base da álgebra de Clifford com a finalidade de que as identidades de Fierz-Pauli-Kofink sejam satisfeitas. Estudamos também os ingredientes principais da classificação de espinores elaborada por Lounesto. Por último, construiremos três novas classes de espinores via o teorema da inversão a partir da premissa que o covariante bilinear $J_{\mu}$ seja nulo. Como consequência desta consideração esses novos espinores não possuem a dinâmica de Dirac, haja visto que $J_{\mu}$ na teoria de Dirac representa a corrente conservada. O surgimento de apenas três novas classes de espinores é uma consequência direta da imposição de que as identidades de Fierz-Pauli-Kofink sejam satisfeitas.
The present thesis covers four important topics: spinors, bilinear covariants, Lounesto's classification and the inversion theorem. We show and explicit the construction of bilinear covariants for the Elko spinors and the necessity of deformation of the Clifford algebra basis elements in order to satisfy the Fierz-Pauli-Kofink identities. We also study the main ingredients of the classification of spinors elaborated by Lounesto. Finally, we construct three new classes of spinors via the inversion theorem from the premise that the bilinear covariant $J_{\mu}$ is null. As a consequence, these new spinors do not have usual dynamics of Dirac, have seen that $J_{\mu}$ in Dirac's theory represents the conserved current. The emergence of only three new classes of spinors is a direct consequence of the requeriment that Fierz-Pauli-Kofink's identities must hold.
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Faul, Tatjana. "Etude de la Structure des Noyaux Riches en Neutrons autour du Noyau Doublement Magique 78Ni." Phd thesis, Université Louis Pasteur - Strasbourg I, 2007. http://tel.archives-ouvertes.fr/tel-00610309.
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Durant la dernière décennie, les études de la décroissance bêta des isotopes 69,71,73Cu ont mis en évidence le net abaissement de l'orbitale proton 1f5/2 lors du remplissage de l'orbitale neutron1g9/2. Ce phénomène peut être interprété comme le résultat des forces tensorielles entre ces orbitales proton et neutron. Un argument similaire prédit l'affaiblissement du gap N=50 quand on s'approche du noyau 78Ni du fait de l'attraction entre les configurations 1g9/2 et1d5/2 avec l'orbitale 1f5/2 et de la répulsion entre les états 1g7/2 et 1f5/2. Ainsi, les noyaux au voisinage de noyau 78Ni, sont les meilleurs candidats pour étudier l'évolution de la fermeture de couche N=50 et les autres aspects du modèle en couches à grand rapport N/Z. De telles études nécessitent des appareillages performants comme la combinaison d'un spectromètre de noyaux de recul de grande acceptance (PRISMA) couplé à un multidétecteur gamma à grande granularité, CLARA à Legnaro (Italie). Lors d'une récente expérience, des résidus exotiques ont été produits via des réactions profondément inélastiques entre un faisceau de 82Se (Elab = 515 MeV) et une cible d'Uranium. Je me suis principalement penchée sur les systématiques des isotopes de Ge et Zn. Dans le but de compléter ces données, une expérience de décroissance bêta, réalisée auprès d'ISOLDE au CERN, des isotopes impairs riches en neutrons de Cu a également été étudiée. Les schémas de décroissance pour les isotopes 71,73,75Cu ont été construit, pour la première fois pour l'élément le plus exotique. La complémentarité des données issues de ces deux mécanismes ouvre de nouvelles perspectives en vue de l'étude des noyaux riches en neutrons.
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Neuman, Erica L. "The Social and Psychological Costs of Avoiding Taxes: An Archival Analysis of Firm and Peer Effects." Case Western Reserve University School of Graduate Studies / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=case1586462862248405.
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Sosa, Laguna Alejandra, and Chávez Elizabeth Jannet Castillo. "El efecto del efficient market theory sobre las decisiones de asesores financieros : ¿por qué creemos que somos mejores inversionistas de lo que de verdad somos?" Bachelor's thesis, Universidad del Pacífico, 2020. http://hdl.handle.net/11354/2652.
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Por años se ha discutido si la estrategia más efectiva para invertirlo es la gestión pasiva o la activa. La gestión pasiva consiste en seguir el comportamiento del mercado, mientras que la gestión activa consiste en tomar decisiones de inversión para intentar superar o vencer al mercado. La teoría de mercados eficientes formulada por Eugene Fama en 1970 sostiene que los precios de los valores reflejan toda la información disponible y, dado que todos los participantes tienen acceso a la misma información, nadie podría obtener beneficios adicionales. Entonces ¿por qué creemos que somos mejores inversionistas de lo que de verdad somos? Los estudios en finanzas conductuales analizan los efectos de sesgos psicológicos sobre el proceso de toma de decisiones de los inversionistas. Se encontró que los inversores están sujetos a muchos sesgos y errores cognitivos, como el exceso de confianza, la aversión a la pérdida, los sesgos de confirmación, de atribución y de retrospección. En este sentido, el presente trabajo de investigación plantea como hipótesis que existen diferentes factores psicológicos que tienen un impacto en el proceso de toma de decisiones de inversión de los agentes.
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Júnior, Antônio Espósito. "Equações integrais via teoria de domínios: problemas direto e inverso." Universidade do Estado do Rio de Janeiro, 2008. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=772.
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Apresenta-se um estudo em Teoria de Domínios das equações integrais da forma geral
f (x) = h(x)+g Z b(x)
a(x)
g(x, y, f (y))dy
com h, a e b definidas para x ∈ [a0,b0], a0 ≤a(x)≤b(x)≤b0 e g definida para x, y ∈ [a0,b0], cujo lado direito define uma contração sobre o espaço métrico de funções reais contínuas
limitadas. O ponto de partida desse trabalho é a reescrita da Análise Intervalar para Teoria de Domínios do problema de valor incial em equações diferenciais ordinárias que possuem
solução como ponto fixo do operador de Picard. Com o conjunto dos números reais interpretados pelo Domínio Intervalar, as funções reais são estendidas para operarem no domínio de funçoes intervalares de variável real. Em particular, faz-se a extensão canônica do campo vetorial em relação à segunda variável. Nesse contexto, pela primeira vez tem-se o estudo das equações integrais de Fredholm e Volterra sobre o domínio de funções intervalares de variável real definida pelo operador integral intervalar com a participação da extensão canônica de g em relação à terceira variável. Adicionando ao domínio de funções intervalares sua função medição, efetua-se a análise da convergência do operador intervalar de Fredholm e Volterra em Teoria de Domínios com o cálculo da sua derivada
informática em relação à medição no seu ponto fixo. Com a representação das funções intervalares em função passo constante a partir da partição do intervalo [a0,b0], reescrevese
o algoritmo da Análise Intervalar em Teoria de Domínios com a introdução do cálculo da aproximação da extensão canônica de g e com o comprimento do intervalo da partição tendendo para zero. Estende-se essa abordagem mais completa do estudo das equações integrais na resolução de problemas de valores iniciais e valor de contorno em equações diferenciais ordinárias e parciais. Uma vez que para uma pequena variação do campo
vetorial v ou do valor inicial y0 da equação diferencial f ′(x) = v(x, f (x)) com a condição inicial f (x0) = y0, pode-se ter uma solução tão próxima da solução f da equação quanto
possível, formaliza-se pela primeira vez em Teoria de Domínios um algoritmo na resolução do problema inverso em que, conhecendo a função f , determina-se uma equação diferencial
ordinária com o cálculo de um campo vetorial v tal que o operador de Picard associado mapeia f tão próxima quanto possível a ela mesma.We present a study in Domain Theory of integral equations of the form f (x) = h(x)+g Z b(x) a(x) g(x, y, f (y))dy for a0 ≤ a(x) ≤ b(x) ≤ b0 with h, a, b defined for x ∈ [a0,b0] and g defined for x, y ∈ [a0,b0], in which the right-hand side defines a contraction on the metric space of continuous realvalued functions on [a0,b0]. The starting point of this work is to revisit Interval Analysis in Domain Theory for the initial-value problem in ordinary differential equations where a solution is expressed as a fixed point of the Picard operator. With the set of real numbers interpreted as the interval domain, real-valued functions are extended to work in the space of interval-valued functions of the real variable domain. In particular, the vector field is extended in the second argument. Under these conditions, for the first time Fredholm and Volterra integral equations have solutions expressed as fixed points of a contraction mapping in terms of the splitting on interval-valued functions of the real variable domain. The measurement for interval-valued functions of the real variable domain is considered where we can asssess the convergence properties of the interval integral operator by means of the informatic derivative. The proposed techniques are applied to more general methods in ordinary differencial equations (ODEs) and partial differential equations (PDEs). For the first time, an algorithm is proposed to provide solutions to the inverse problem for Odinary Differential Equation where, given a function f , it is found a vector field v that defines a Picard operator which maps the solution f as close as possible to itself, such that the ODE f ′(x) = v(x, f (x)) admits f as either an exact or, as closely as desired, an approximate solution.
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Carvalho, Rafael Aleixo de. "Tempo de transito em meios com isotropia transversal vertical (VTI) : aproximações e inversão dos parametros." [s.n.], 2009. http://repositorio.unicamp.br/jspui/handle/REPOSIP/307310.
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Orientador: Jorg Dietrich Wilhelm SchleicherTese (doutorado) - Universidade Estadual de Campinas, Instituto de Matematica, Estatistica e Computação Cientifica
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Resumo: Como os alvos de exploração tornaram-se mais profundos, os comprimentos dos cabos têm aumentado em conformidade, fazendo a aproximação hiperbólica convencional produzir tempos de trânsito cada vez mais imprecisos. Em outras palavras, para as modernas geometrias de aquisição para grandes afastamentos, a aproximação hiperbólica já não é suficiente para horizontalizar a família CMP por causa da não homogeneidade ou anisotropia dos meios. Para resolver este problema, muitas fórmulas para o tempo de trânsito foram propostas na literatura que fornecem aproximações de qualidade diferente. Demonstrou-se que para meios com isotropia transversal vertical (meios VTI), apenas dois parâmetros do tempo de trânsito são suficientes para a realização de todo o processamento temporal, sendo a velocidade NMO e um parâmetro de anisotropia. Por isso, nesta tese, nos concentramos, na dedução de aproximações simples para o tempo de trânsito que dependem de um único parâmetro de anisotropia. Começamos por dar uma visão geral de uma coleção de tais aproximações para o tempo de trânsito encontradas na literatura e comparar suas qualidades. Em seguida, deduzimos um conjunto de novas aproximações para o tempo de trânsito que dependem de um parâmetro baseado em aproximações encontradas na literatura. A principal vantagem das nossas aproximações é que algumas delas são expressões analíticas bastante simples que as tornam fáceis de serem utilizadas, ao mesmo tempo que têm a mesma qualidade ou maior que as fórmulas já estabelecidas. Utilizamos estas aproximações para o tempo de trânsito para uma inversão dos parâmetros de anisotropia. Utilizando uma estimativa da velocidade NMO a partir da análise de velocidades hiperbólica, pode-se estimar o parâmetro anisotrópico a partir de uma aproximação para o tempo de trânsito mais geral. Estendemos o procedimento em dois passos utilizando um termo não hiperbólico mais preciso na aproximação para o tempo de trânsito. As aproximações para o tempo de trânsito deduzidas permitem predizer o viés na estimativa da velocidade NMO, proporcionando assim um meio de corrigir, tanto a estimativa a velocidade NMO, quanto o conseqüente valor do parâmetro de anisotropia. Por meio de um exemplo numérico, demonstramos que a estimativa dos parâmetros do tempo de trânsito, usando este processo iterativo, apresenta considerável melhora. Palavras-chave: Aproximação para tempos de trânsito, meios VTI, análise de velocidade e geofísica
Abstract: As exploration targets have become deeper, cable lengths have increased accordingly, making the conventional two term hyperbolic traveltime approximation produce increasingly erroneous traveltimes. In other words, for modern long-offset acquisition geometries, a hyperbolic traveltime approximation is no longer sufficient to flatten the CMP gather because of medium inhomogeneity or anisotropy. To overcome this problem, many traveltime formulas were proposed in the literature that provide approximations of different quality. It has been demonstrated that for transversly isotropic media with a vertical symmetry axis (VTI media), just two traveltime parameters are sufficient to perform all time-related processing, being the NMO velocity and one anisotropy parameter. Therefore, we concentrate in this thesis,on simple traveltime approximations that depend on a single anisotropy parameter. We start by giving an overview of a collection of such traveltime approximations found in the literature and compare their quality. Next, we derive a set of new single-parameter traveltime approximations based on the ones found in the literature. The main advantage of our approximations is that some of them are rather simple analytic expressions that make them easy to use, while achieving the same quality as the better of the established formulas. We then use these traveltime aproximations for an inversion of the anisotropy parameters. Using an estimate of the NMO velocity from a hyperbolic velocity analysis, one can estimate the anisotropic parameter from a more general traveltime approximation. We extend this two-step procedure using a more accurate nonhyperbolicity term in the traveltime approximation. The used traveltime approximations allow to predict the bias in the NMO velocity estimate, thus providing a means of correcting both the estimated NMO velocity and the resulting anisotropy parameter value. By means of a numerical example, we demonstrate that the estimation of the traveltime parameters, using this iterative procedure, is improved considerably. Keywords: Traveltime approximations, VTI media, velocity analysis and geophysics
Doutorado
Geofisica Computacional
Doutor em Matemática Aplicada
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Konečný, Zdeněk. "Statistická analýza složených rozdělení." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229488.
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The probability distribution of a random variable created by summing a random number of the independent and identically distributed random variables is called a compound probability distribution. In this work is described a compound distribution as well as a calculation of its characteristics. Especially, the thesis is focused on studying a special case of compound distribution where each addend has the log-normal distribution and their number has the negative binomial distribution. Here are also described some approaches to estimate the parameters of LN and NB distribution. Further, the impact of these estimates on the final compound distribution is analyzed.
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Luque, García Ander. "Diálogo con el lector y “promesa de obra” como obra literaria: La inversión emisor-receptor a partir de la novelística de Macedonio Fernández." Doctoral thesis, Universitat de Barcelona, 2017. http://hdl.handle.net/10803/458873.
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El trabajo de tesis doctoral Diálogo con el lector y “promesa de obra” como obra literaria parte de las teorías artístico-literarias de la novela del pensador argentino Macedonio Fernández, definidas a lo largo de numerosos ensayos, textos, papeles y encarnadas y culminadas en sus dos obras gemelas: Adriana Buenos Aires (Última novela mala) y Museo de la Novela de la Eterna (Primera novela buena). El autor demasiado innovador para la tradición novecentista, pero demasiado anticuado para el Vanguardismo hispanoamericano. Tolerado y/o alabado por numerosos autores de entre aquellos ismos, Macedonio Fernández ejerció su influencia sobre la literatura argentina desde que se centró en su actividad literaria a principios del siglo XX hasta su muerte en la década de los años 50. Un deceso que dio un nuevo valor a su obra, redescubierta gracias a su hijo y a Jorge Luis Borges a partir de la década de los 60, y que encontró en su inacabamiento uno de sus principales valores: la obra definitivamente abierta, por definición y voluntad autoral, que más tarde perfilaría Umberto Eco.
En un primer acercamiento, este trabajo definirá y acotará el grueso de las teorías macedonianas sobre el arte, la literatura, la novela y el humor, todas ellas parte integral de la realización de sus dos novelas, haciendo hincapié en dos aspectos centrales e íntimamente relacionados: por un lado, las consecuencias de esa apertura de obra, encarnada en una voluntad de su autor por mostrar en todo el momento el proceso constructivo de su ideal de novela dentro de la propia novela (especialmente de Museo de la Novela de la Eterna, formulación explícita definitiva de sus teorías); y por otro, el papel crucial que en tal contexto adquiere el lector, ascendido a co-creador responsable de la novela.
Partiendo de esta base, el grueso del trabajo plantea una evolución histórica de la novela como obra abierta y de la progresiva inversión de los papeles de emisor y receptor a través del tiempo, desde la decadencia de la épica hasta la caída del autor-dios como demiurgo, proclamada abiertamente por Roland Barthes en años posteriores a la muerte del autor argentino que centra nuestro análisis, y llegando así a hasta la actualidad.
De este modo, saltando constantemente de Macedonio Fernández a la teoría y de la teoría a Macedonio Fernández, este trabajo pretende, en última instancia, situar la figura del autor argentino dentro de una larga tradición literaria más allá de las fronteras de su país, remarcando su contribución a la misma a lo largo de su vida, y más allá a través de sus discípulos y admiradores, entre cuyos miembros de calado más recientes destaca Enrique Vila-Matas.This thesis takes the artistic and literary theories of Macedonio Fernández as a starting point, based on his numerous texts and essays (papeles) and his twin novels Adriana Buenos Aires (“the last bad novel”) and Museo de la Novela de la Eterna (“the first good novel”). An author between two worlds, too innovative for the literary traditions of the late 19th century, yet too outdated for the Spanish American Avant-Garde, Fernández left his mark on many Argentinian authors during his literary life, especially from the 1920s to the 1950s. Upon his death, his works became known thanks to his son and Jorge Luis Borges, and his influence extends up to these days. Grounding this thesis upon his theories of the “open work” (afterwards formulated by Umberto Eco), the promise of a work as the literary work itself and the inclusion of the reader in the creative process of the novels, we start a historical tour, tracking those ideas throughout literary tradition. As a result, we present the evolution of the novel conceived as an “open work” and the progressive inversion of the roles between the transmitter and the receiver of the literary work. From the decadence of the epos to the fall of the author-god as a demiurge, openly proclaimed by Roland Barthes in “The death of the author” years after the death of our Macedonio Fernández, we jump from the Argentinian writer’s theories to Reception Aesthetics and the theory of the novel. The final goal of this thesis is to acknowledge Fernández’ contribution to the history of literature, as he has often been secluded in the Spanish American tradition and forgotten in the big picture, even if his influence transcends the Spanish-speaking countries .
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Murphy, David S. "Las decisiones de los inversionistas a través del lente de la economía del comportamiento." Pontificia Universidad Católica del Perú, 2013. http://repositorio.pucp.edu.pe/index/handle/123456789/114853.
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Traditional economic theory postulates that people are rational. This implies that people make decisions to maximize their utility functions and to do this, that they have fully and correctly evaluated their preferences and limitations. Behavioral economics recognizes that this is not always true, that sometimes information is incomplete. This article is examines some of the effects of behavioral economics (which come largely from cognitive psychology) in decision-making by investors in the stock exchanges.La teoría económica tradicional postula que las personas son racionales. Esto implica que las personas toman decisiones para maximizar sus funciones de utilidad, y que para hacer esto han evaluado de forma completa y correcta sus preferencias y limitaciones. La economía del comportamiento reconoce que esto no es siempre verdad; que a veces no existe suficiente información. En este artículo, examino algunos de los efectos de la economía del comportamiento (que vienen en gran parte de la psicología cognitiva) en la toma de decisiones por los inversionistas en las bolsas de valores.
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Acevedo, Nancy Isabel Alvarez. "Uma formulação explícita matricial para problemas inversos de transferência radiativa em meios participantes homogêneos unidimensionais." Universidade do Estado do Rio de Janeiro, 2006. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=372.
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Fundação Carlos Chagas Filho de Amparo a Pesquisa do Estado do Rio de JaneiroA formulação explícita matricial desenvolvida nesta tese de doutorado foi proposta visando ser uma alternativa na solução de Problemas Inversos de estimativa de propriedades radiativas em meios participantes homogêneos unidimensionais usando a Equação de Transferência Radiativa para modelar a interação da radiação com o meio participante. A equação de transporte é formulada em forma matricial e o domínio angular é discretizado usando conceitos do método de ordenadas discretas e a expansão da função de fase do espalhamento anisotrópico em uma série de polinômios de Legendre. A formulação proposta consiste em uma formulação explícita para o problema inverso. Um arranjo apropriado das condições de contorno prescritas (fluxos incidentes) e dos fluxos emergentes nos contornos de uma placa permitem o cálculo direto do operador de transmissão, do operador albedo e do operador de colisão. A partir do operador de colisão calculado são obtidos os valores estimados dos coeficientes de extinção total e de espalhamento. São apresentadas as formulações para problemas em regime estacionário e em regime transiente, bem como os resultados para alguns casos-teste.
The explicit matrix formulation developed in the present thesis has been proposed as an alternative for the solution of Inverse Problems for radiative properties estimation in one-dimensional homogeneous participating media using Radiative transfer equation for the modeling of the radiation interaction with the participating medium. This transport equation is formulated in a matrix form and the angular domain is discretized using concepts of the discrete ordinates methods and the expansion of the function of phase function of anisotropic scattering in a series of Legendre polynomial. The formulation proposed consists on an explicit formulation for the inverse problem. An adequate assembly of the prescribed boundary conditions (incidents flux) and of the emerging flux at the boundaries of the slab allows the direct computation of the transmission, albedo and collision operators. From the computed collision operator estimated values for total extinction and scattering coefficients are obtained. The formulations for steady state and transient situations are presented, as well as test case results.
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Vogt, Andreas. "Analytische und numerische Untersuchung von direkten und inversen Randwertproblemen in Gebieten mit Ecken mittels Integralgleichungsmethoden." [S.l.] : [s.n.], 2001. http://webdoc.sub.gwdg.de/diss/2002/vogt/vogt.pdf.
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Silva, Daniel Guerreiro e. 1983. "Aprendizado de máquina baseado na teoria da informação : contribuições à separação de sinais em corpos finitos e inversão de sistemas de Wiener." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/261122.
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Orientadores: Romis Ribeiro de Faissol Attux, Jugurta Rosa Montalvão FilhoTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação
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Resumo: Esta tese de doutorado possui como tema geral o desenvolvimento de algoritmos de Aprendizado de Máquina Baseado na Teoria da Informação (ITL - Information Theoretic Learning). O paradigma de ITL propõe o uso de critérios de treinamento baseados em medidas como entropia e informação mútua, em substituição aos tradicionais critérios baseados em estatísticas de segunda ordem. Os problemas de inversão cega de sistemas de Wiener e separação cega de sinais em corpos de Galois são os objetos de estudo e desenvolvimento dessas ferramentas. Estes problemas apresentam características marcantes quanto à necessidade de descritores estatísticos de ordem superior, por isso, apresenta-se uma série de contribuições que se baseiam em critérios de ITL e empregam algoritmos imuno-inspirados (ou heurísticas de busca) para adaptar os parâmetros dos modelos envolvidos. As propostas desenvolvidas abrem a perspectiva de futuras aplicações em áreas como genômica, codificação e geofísica. Espera-se também que os resultados apresentados fortaleçam um entendimento mais amplo de ITL, a fim de abranger estratégias mais genéricas de busca, de estimação de informação e de modelagem de dados
Abstract: The main theme of this thesis is the development of Information Theoretic Learning (ITL) algorithms. The ITL paradigm proposes the adoption of training criteria based on information measures such as entropy and mutual information, instead of traditional criteria based on second order statistics. The problems of blind inversion of Wiener systems and blind separation of signals over Galois fields are the tasks over which these tools are applied. Such problems present key aspects that establish a demand for higher order statistics, hence we present several contributions that are based on ITL criteria and employ immune-inspired algorithms (or heuristic-based methods) to perform the adaptation of the parameters of each related model. The developed proposals open the perspective of future applications in genomic, coding theory and geophysics. Furthermore, we expect that the presented results support a wider understanding of ITL, in order to comprise more general strategies of search, information estimation and data modeling
Doutorado
Engenharia de Computação
Doutor em Engenharia Elétrica
50
Ferreira, Luan Alberto. "Teoria de corpos de classe e aplicações." Universidade de São Paulo, 2012. http://www.teses.usp.br/teses/disponiveis/55/55135/tde-05122012-102820/.
Full textAbstract:
Neste projeto, propomos estudar a chamada \"Teoria de Corpos de Classe,\" que oferece uma descrição simples das extensões abelianas de corpos locais e globais, bem como algumas de suas aplicações, como os teoremas de Kronecker-Weber e Scholz-ReichardtIn this work, we study the so called \"Class Field Theory\", which give us a simple description of the abelian extension of local and global elds. We also study some applications, like the Kronecker-Weber and Scholz-Reichardt theorems