Rozprawy doktorskie na temat „Symmetric mean”

Spinodal instability mechanism and early development of density fluctuations for symmetric nuclear matter at finite temperature are studied. A stochastic extension of Walecka-type relativistic mean-field model including non-linear self-interactions of scalar mesons with NL3 parameter set is employed in the semi-classical approximation. The growth rates of unstable collective modes are investigated below the normal density and at low temperatures. The system exhibits most unstable behavior in longer wave lengths at baryon densities &rho
B = 0.4 &rho
0 , while most unstable behavior occurs in shorter wavelengths at lower baryon densities &rho
B = 0.2 &rho
0 . The unstable response of the system shifts towards longer wavelengths with the increasing temperature at both densities. The early growth of the density correlation functions are calculated, which provide valuable information about the initial size of the condensation and the average speed of condensing fragments. Furthermore, the relativistic results are compared with Skyrme type non-relativistic calculations. Qualitatively similar results are found in both non-relativistic and relativistic descriptions.

The nuclear matter liquid-gas phase transition is expected to be a signal of nuclear spinodal instabilities as a result of density fluctuations. Nuclear spinodal instabilities in symmetric nuclear matter are studied within a stochastic relativistic density-dependent model in semi-classical approximation. We use two parameterization for the Lagrange density, DDME1 and TW sets. The early growth of density fluctuations is investigated by employing relativistic Vlasov equation based on QHD and discussed the cluster size of the condensations from the early growth of density correlation functions. Expectations are that hot nuclear matter behaves unstable around &rho
b &asymp
&rho
0/4 (below the saturation density) and at low temperatures. We therefore present our results at low temperature T=1 MeV and at higher temperature T=5 MeV, and also at a lower initial baryon density &rho
b = 0.2 &rho
0 and a higher value &rho
b = 0.4 &rho
0 where unstable behavior is within them. Calculations in density-dependent model are compared with the other calculations obtained in a relativistic non-linear model and in a Skyrme type nonivrelativistic model. Our results are consistent with them. Qualitatively similar results show that the physics of the quantities are model-independent. The size of clusterization is estimated in two ways, by using half-wavelength of the most unstable mode and from the width of correlation function at half maximum. Furthermore, the average speed of condensing fragments during the initial phase of spinodal decomposition are determined by using the current density correlation functions.

The first part of the work is devoted to mean-field games with absorption, a class of games that can be viewed as natural limits of symmetric stochastic differential games with a large number of players who, interacting through a mean-field, leave the game as soon as their private states hit a given boundary. In most of the literature on mean-field games, all players stay in the game until the end of the period, while in many applications, especially in economics and finance, it is natural to have a mechanism deciding when a player has to leave. Such a mechanism can be modelled by introducing an absorbing boundary for the state space. The second part of the thesis, deals with mean-field games of finite-fuel capacity expansion with singular controls. While singular control problems with finite (and infinite) fuel find numerous applications in the economic literature and originated from the engineering literature in the late 60’s, many-player game versions of these problems have only very recently been introduced. They are a natural extension of the single agent set-up and allow to model numerous applied situations. In our work in particular, we make assumptions on the structure of the interaction across players that are suitable to model the so-called goodwill problem. Altogether, the original contribution to the mean-field games literature of the present work is threefold. First, it contributes to the development of mean-field games with absorption, continuing the work of Campi and Fischer (2018) and considerably generalizing the original model by relaxing the assumptions and setting it into a more abstract, infinite-dimensional, framework. Second, it introduces a new set of tools to deal with mean-field games with singular controls, extending the well-known connection between singular stochastic control and optimal stopping to mean-field games. Finally, it also contributes to the numerical literature on mean-field games, by proposing a numerical scheme to approximate the solutions of mean-field games with singular controls with a constructive approach. Overall, this thesis focuses on newly introduced branches of the theory of meanfield games that display a high potential for economic and financial applications, contributing to the literature not only by further developing the existing theory but also by working in directions that make the these models more suitable to applications

Master of Science
Department of Statistics
Paul Nelson
Trimmed means are robust estimators of location for distributions having heavy tails. Theory and simulation indicate that little efficiency is lost under normality when using appropriately trimmed means and that their use with data from distributions with heavy tails can result in improved performance. This report uses the principle of equivariance applied to trimmed means sampled from a Cauchy distribution to form a discrepancy function of the data and parameters whose distribution is free of the unknown median and scale parameter. Quantiles of this discrepancy function are estimated via asymptotic normality and simulation and used to construct confidence intervals for the median of a Cauchy distribution. A nonparametric approach based on the distribution of order statistics is also used to construct confidence intervals. The performance of these intervals in terms of coverage rate and average length is investigated via simulation when the data are actually sampled from a Cauchy distribution and when sampling is from normal and logistic distributions. The intervals based on simulation estimation of the quantiles of the discrepancy function are shown to perform well across a range of sample sizes and trimming proportions when the data are actually sampled from a Cauchy distribution and to be relatively robust when sampling is from the normal and logistic distributions.

Provamos resultados sobre a geometria de hipersuperfícies em diferentes espaços ambiente. Primeiro, definimos uma aplicação de Gauss generalizada para uma hipersuperfície Mn-1 c/ Nn, onde N é um espaço simétrico de dimensão n ≥ 3. Em particular, generalizamos um resultado de Ruh-Vilms e apresentamos aplicações. Em seguida, estudamos superfícies em espaços de dimensão 3: estudamos a equação da curvatura média em um produto semidireto R2oAR e obtemos estimativas da altura e a existência de gráficos mínimos do tipo Scherk. Finalmente, no espaço ambiente de uma variedade hiperbólica de dimensão 3: nós apresentamos condições suficientes para que um mergulho completo de uma superfície ∑ de topologia finita em N com curvatura média |H∑| ≤ 1 seja próprio.
We prove results concerning the geometry of hypersurfaces on di erent ambient spaces. First, we de ne a generalized Gauss map for a hypersurface Mn-1 c/ Nn, where N is a symmetric space of dimension n ≥ 3. In particular, we generalize a result due to Ruh-Vilms and make some applications. Then, we focus on surfaces on spaces of dimension 3: we study the mean curvature equation of a semidirect product R2 oA R to obtain height estimates and the existence of a Scherk-like minimal graph. Finally, on the ambient space of a hyperbolic manifold N of dimension 3 we give su cient conditions for a complete embedding of a nite topology surface ∑ on N with mean curvature |H∑| ≤ 1 to be proper.

The field of statistics is becoming increasingly more important as the amount of data in the world grows. This thesis studies the Growth Curve model in multivariate statistics which is a model that is not widely used. One difference compared with the linear model is that the Maximum Likelihood Estimators are more complicated. That makes it more difficult to use and to interpret which may be a reason for its not so widespread use. From this perspective this thesis will compare the traditional mean estimator for the Growth Curve model with the unweighted mean estimator. The unweighted mean estimator is simpler than the regular MLE. It will be proven that the unweighted estimator is in fact the MLE under certain conditions and examples when this occurs will be discussed. In a more general setting this thesis will present conditions when the un-weighted estimator has a smaller covariance matrix than the MLEs and also present confidence intervals and hypothesis testing based on these inequalities.

Dans les années 1970, Vautherin et Brink ont effectué les premiers calculs auto-consistents du problème à N-corps nucléaire en utilisant une interaction de Skyrme. Aujourd’hui la méthode de la fonctionnelle de densité (EDF) ou la méthode champ-moyen est toujours utilisée à grande échelle pour étudier la structure nucléaire. Le premier point fort de cette méthode est sa simplicité computationnelle qui permet de l'appliquer dans l'entièreté de la charte nucléaire, des noyaux les plus légers aux éléments super lourds à plus que 250 nucléons. Depuis le début des années 1980, les initiales `BFH', représentant Paul Bonche, Hubert Flocard et Paul-Henri Heenen, ont signé un grand nombre des papiers depuis 1984. Ces trois scientifiques sont les auteurs de trois codes numériques iconiques EV8, CR8 et EV4. Des versions évoluées de ces codes sont toujours utilisées fréquemment aujourd’hui par des nombreux chercheurs. Au fil des années, deux désavantages de ces trois codes sont apparus. Le premier désavantage est lié à la physique: bien que EV8, EV4 et CR8 offrent à l'utilisateur accès à une variété de combinaisons de symétries conservées et brisées, un grand nombre n'est pas accessible. De plus en plus souvent, les applications traitant des noyaux exotiques demandent des calculs champ-moyen qui sont moins limités par les symétries imposées. Le deuxième désavantage est d'une nature plus pratique: le maintien au même niveau d'une combinaison de trois codes qui ont des buts comparables est difficile. Le projet de mon doctorat était de construire un code qui unifie et généralise les fonctionnalités de EV8, CR8 et EV4. Aujourd'hui MOCCa, un acronyme de MOdular Cranking Code, est capable de reproduire toutes les fonctionnalités des codes BFH. De plus, il est maintenant possible d'effectuer des calculs champ-moyen pour un nombre des combinaisons de symétries conservées et brisées, offrant un domaine d'applications énorme. Quatre symétries ont été toujours imposées dans les codes BFH, et sont maintenant toutes soumises au choix de l'utilisateur, qui peut les conserver où les briser indépendamment. Ceci résulte en 16 modes d'opération différents du code, dont tous ont des intérêts physiques pour décrire des phénomènes nucléaires. La déformation octupolaire du 224Ra et les bandes chirales du 138Nd sont des exemples récents d'intérêt expérimental, dont la description théorique est maintenant abordable avec un seul outil. Cet outil fait preuve d'une grande complexité: sur le plan physique, des méthodes ont été développées pour résoudre les équations du champ-moyen en l'absence des symétries facilitant le problème, tandis que sur le plan pratique, le traitement d'un nombre de degrés de liberté non-physiques a eté amelioré. La dernière partie de la thèse, la plus importante probablement du point de vue des futurs collaborateurs, est pour cette raison constituée d'un manuel d'utilisateur. Deux applications de la méthode sont ainsi présentées: la description des transitions de forme dans les isotopes de Radium et une étude de l'évolution des rayons de charge dans la chaîne isotopique du mercure démontrent la viabilité de la méthode.
Option Physique du Doctorat en Sciences
info:eu-repo/semantics/nonPublished

We introduce the notion of special spherical symmetry and classify the complete regular minimal surfaces in the three sphere having this symmetry. We also show that the Clifford torus is the unique embedded minimal torus in three sphere possessing special spherical symmetry.

In recent years symplectic geometry and symplectic topology have grown to large subbranches in mathematics and had a great impact on other areas in mathematics. When interested in geometry, a geometer always considers geometric structures that arise on immersed submanifolds. In symplectic geometry there is a distinguished class of immersions, known as Lagrangian submanifolds . In particular, minimal Lagrangian submanifolds, called special Lagrangians, are very important in mirror symmetry. Lagrangian mean curvature flow is an important example of Lagrangian deformation. From which we can get the special Lagrangian submanifolds. In recent years, there have been many papers about this subject and the result by K.Smoczyk and Mu-Tao Wang [WS] is very important and beautiful. Our main purpose in this article is to give a new proof for the main result in [WS] from the viewpoint of fully nonlinear partial differential equations.

La symétrie est une propriété géométrique importante en perception visuelle qui traduit notre perception des correspondances entre les différents objets ou formes présents dans une scène. Elle est utilisée comme élément caractéristique dans de nombreuses applications de la vision par ordinateur (comme par exemple la détection, la segmentation ou la reconnaissance d'objets) mais également comme une caractéristique formelle en sciences de l'art (ou en analyse esthétique). D’importants progrès ont été réalisés ces dernières décennies pour la détection de la symétrie dans les images mais il reste encore de nombreux verrous à lever. Dans cette thèse, nous nous intéressons à la détection des symétries de réflexion, dans des images réelles, à l'échelle globale. Nos principales contributions concernent les étapes d'extraction de caractéristiques et de représentation globale des axes de symétrie. Nous proposons d'abord une nouvelle méthode d'extraction de segments de contours à l'aide de bancs de filtres de Gabor logarithmiques et une mesure de symétrie intersegments basée sur des caractéristiques locales de forme, de texture et de couleur. Cette méthode a remporté la première place à la dernière compétition internationale de symétrie pour la détection mono- et multi-axes. Notre deuxième contribution concerne une nouvelle méthode de représentation des axes de symétrie dans un espace linéaire-directionnel. Les propriétés de symétrie sont représentées sous la forme d'une densité de probabilité qui peut être estimée, de manière non-paramétrique, par une méthode à noyauxbasée sur la distribution de Von Mises-Fisher. Nous montrons que la détection des axes dominants peut ensuite être réalisée à partir d'un algorithme de type "mean-shift” associé à une distance adaptée. Nous introduisons également une nouvelle base d'images pour la détection de symétrie mono-axe dans des photographies professionnelles issue de la base à grande échelle AVA (Aestetic Visual Analysis). Nos différentes contributions obtiennent des résultats meilleurs que les algorithmes de l'état de l'art, évalués sur toutes les bases disponibles publiquement, spécialement dans le cas multi-axes. Nous concluons que les propriétés de symétrie peuvent être utilisées comme des caractéristiques visuelles de niveau sémantique intermédiaire pour l'analyse et la compréhension de photographies
Symmetry is a fundamental principle of the visual perception to feel the equally distributed weights within foreground objects inside an image. It is used as a significant visual feature through various computer vision applications (i.e. object detection and segmentation), plus as an important composition measure in art domain (i.e. aesthetic analysis). The development of symmetry detection has been improved rapidly since last century. In this thesis, we mainly aim to propose new approaches to detect reflection symmetry inside real-world images in a global scale. In particular, our main contributions concern feature extraction and globalrepresentation of symmetry axes. First, we propose a novel approach that detects global salient edges inside an image using Log-Gabor filter banks, and defines symmetry oriented similarity through textural and color around these edges. This method wins a recent symmetry competition worldwide in single and multiple cases.Second, we introduce a weighted kernel density estimator to represent linear and directional symmetrical candidates in a continuous way, then propose a joint Gaussian-vonMises distance inside the mean-shift algorithm, to select the relevant symmetry axis candidates along side with their symmetrical densities. In addition, we introduce a new challenging dataset of single symmetry axes inside artistic photographies extracted from the large-scale Aesthetic Visual Analysis (AVA) dataset. The proposed contributions obtain superior results against state-of-art algorithms among all public datasets, especially multiple cases in a global scale. We conclude that the spatial and context information of each candidate axis inside an image can be used as a local or global symmetry measure for further image analysis and scene understanding purposes

Le sujet de la thèse est une description théorique et self-consistante de propriétés de noyaux atomiques instables, ainsi que l’étude de l’influence de la structure en couches sur les états de symétrie mixte (ESM). Le but général est de rendre compte de façon microscopique de la structure et des excitations de noyaux atomiques que l’on peut produire à présent auprès des installations faisceaux radioactifs (GANIL, GSI). L’étude des ESM vise à préciser la relation entre la structure microscopique et la symétrie de F-spin dans les noyaux vibrationnels. La base de notre description est le modèle de Skyrme-Hartree-Fock avec un terme tenseur dans l’interaction. Les calculs sont faits pour les chaînes isotopiques Z=14 et Z=50, et les chaînes isotoniques N=28 et N=82. Nous montrons que la composante tenseur de la force est déterminante pour l’évolution de la fermeture de couche dans la chaîne Z=14, tandis qu’elle ne joue qu’un faible rôle dans la fermeture de couche à travers la chaîne N=28. Nous avons ensuite accompli une étude systématique des excitations dipolaires dites résonances Pygmées dans le cadre du modèle QRPA. Le phénomène de « peau de neutrons » a aussi été étudié dans les noyaux riches en neutrons. Dans la dernière partie de la thèse nous avons étudié pour la première fois les ESM dans les noyaux autour de N=80 en utilisant le modèle QPM. Nous avons réussi à décrire dans ce cadre les résultats expérimentaux récents obtenus sur le spectre à basse énergie du noyau 138Ce
Subject of the thesis is the theoretical description of effects in neutron rich nuclei, within a self-consistent approach, as well as the investigation of the influence of the shell structure on the Mixed Symmetry States. The scientific goal is, within a microscopic method, to describe the structure and the excitations of atomic nuclei, which are now available at the radioactive ion facilities at GANIL and GSI. The topic of the Mixed Symmetry States investigation is to specify the mechanism by which the microscopic structure influences the F-spin symmetry in vibrational nuclei. In the development of the thesis, a SHF model has been used. An additional tensor term has been explicitly included. Calculations for the isotopic chains Z=14 and Z=50 as well as for the isotonic chains N=28, 82 have been performed. It was shown that the tensor term is indeed crucial for the evolution of the shell gap with the mass number for Z=14. On the other hand, it was proved that the tensor term has no influence on the shell gap for N=28. By the means of QRPA, a systematical study of slightly collective excitations — the so called Pygmy resonance has been done. Theoretically was investigated the appearance of a structure in neutron rich nuclei known as “neutron skin”. In the framework of QPM it was done a complete survey of MSS for nuclei in the N=80 region. For a first time a microscopical description of such structures in this region has been done. In the framework of this model a description of the recent experimental data on low-lying excitations in 138Ce has been done

Alors qu’il existe de nombreux calculs microscopiques de barrières de fission pour des noyaux composés pair-pairs, il n’y a cependant que relativement peu de tels calculs pour des noyaux de masse impaire. Ceci est dû aux complications induites par la brisure de la symétric de reversement du sens du temps au niveau du champ moyen qui est engendrée par la présence d’un nucleon non apparié. Pour éviter cette difficulté, des calculs existants pour des noyaux de masse impaire ont tout simplement négligé ces effets de brisure de la symétrie de reversement du sens du temps.Dans ce travail, on se donne pour but d’améliorer la description des barrières de fission, aussi bien que des propriétés spectroscopiques du niveau fondamental et de l’état isomérique de fission,pour quelques isotopes de masse impaire dans la région des actinides en prenant en compte de tels effets. Ceci a été réalisé dans le cadre du formalisme de Skyrme–Hartree–Fock plus BCS avec blocking en adaptant ce formalisme à la brisure de la symétrie considérée. L’interaction résiduelle d’appariement a été approchée par une force de séniorité dont les paramètres ont été ajustés pour reproduire les différences de masse pair-impair de quelques noyaux de la région des actinides.Les énergies des têtes de bande rotationnelle de basse énergie ont été calculées dans le cadre du modèle unifié de Bohr-Mottelson pour quatre noyaux bien déformés (235U, 239Pu, 237Np, 241Am)produisant un bon accord qualitatif avec les données pour les noyaux impairs en neutrons. L’accord significativement moins bon obtenu pour les noyaux impairs en protons pourrait résulter de l’usage de l’approximation de Slater pour l’interaction d’échange de Coulomb. Les énergies de déformation de deux noyaux impairs en neutrons (235U, 239Pu) ont été calculées pour quelques configurations de particule individuelle, jusqu’après la barrières de fission externe. La symétrie axiale a été imposée tandis que la brisure de la symétrie droite-gauche (ou de parité intrinsèque) a été permise dans la région de la seconde barrière. Les hauteurs des barrières de fission pour ces noyaux impairs dépendent significativement des configurations de particule individuelle. Un accord qualitatif avec les données disponibles pour les hauteurs de barrières des noyaux impairs considérés et leurs voisins pair-pairs a été généralement obtenu
While there have been numerous microscopic calculations on fission barriers of even-even compoundnuclei, there are however, relatively few such work dedicated to odd-mass nuclei. This is dueto the complications posed by the breaking of the time-reversal symmetry at the mean-field leveldue to the presence of an unpaired nucleon. In order to circumvent this difficulty, previous fission barriercalculations of odd-mass nuclei have been performed by neglecting the effect of time-reversalsymmetry breaking. This work aims to improve on the description of fission barriers as well asthe spectroscopic properties of ground and fission-isomeric state, of some odd-mass actinide nucleiby taking the effect of time-reversal symmetry breaking into account. This has been perfomedwithin a Skyrme-Hartree-Fock-plus-BCS framework with blocking, where the BCS formalism hasbeen adapted to accomodate this symmetry breaking. The Skyrme nucleon-nucleon effective forcehas been used with various sets of parameters (SIII, SkM*, SLy5*). The residual pairing interactionhas been approximated by seniority forces whose neutron and proton parameters have beenfitted to reproduce the odd-even mass differences of some actinide nuclei. The low-lying rotationalband-head energies evaluated within the Bohr-Mottelson unified model have been determined forfour well-deformed odd-nuclei (235U, 239Pu, 237Np, 241Am) yielding a good qualitative agreementto the data for odd-neutron nuclei. The agreement was significantly less good for the odd-protonnuclei, possibly due to the use of the Slater approximation for the exchange Coulomb interaction.The deformation energies of two odd-neutron nuclei (235U and 239Pu) have been calculated forsome single-particle configurations up to a point beyond the outer fission-barrier. Axial symmetrynuclear shape has been assumed while a breaking of the left-right (or intrinsic parity) symmetryhas been allowed around the outer fission-barrier. The fission-barrier heights of such odd-neutronnuclei depend significantly on the particle configurations. A special attention has been paid tothe very important rotational correction to deformation energies. In particular, the correction ofthe moment of inertia calculated from the usual Belyaev expression was considered. Overall, aqualitative agreement with available data on fission-barrier heights for the considered odd-neutronnuclei and their even neighbours has been obtained

My thesis deals with the study of elliptic PDE. It is divided into two parts, the first one concerning a nonlinear equation involving the p-Laplacian, and the second one focused on a nonlocal problem. In the first part, we study the regularity of stable solutions to a nonlinear equation involving the p-Laplacian in a bounded domain. This is the nonlinear version of the widely studied semilinear equation involving the classical Laplacian. Stable solutions to semilinear equations have been very recently proved to be bounded, and therefore smooth, up to dimension n=9 by Cabré, Figalli, Ros-Oton, and Serra. This result is known to be optimal by counterexamples in higher dimensions. In the case of the p-Laplacian, the boundedness of stable solutions is conjectured to hold up to a critical dimension depending on p. Examples of unbounded stable solutions are known if the dimension exceeds the critical one. Moreover, in the radial case or under strong assumptions on the nonlinearity, stable solutions are proved to be bounded in the optimal dimension range. We prove the boundedness of stable solutions under a new condition on n and p, which is optimal in the radial case, and more restrictive in the general one. It improves the known results in the field, and it is the first example, concerning the p-Laplacian, of a technique providing both a result in the nonradial case and the optimal result in the radial case. In the first part, we also investigate Hardy-Sobolev inequalities on hypersurfaces of Euclidean space, all containing a mean curvature term. Our motivation comes from several applications of these inequalities to the study of a priori estimates for stable solutions. Specifically, we give a simplified proof of the celebrated Michael-Simon and Allard inequality, we obtain two new forms of the Hardy inequality on hypersurfaces, and an improved Hardy inequality in the Poincaré sense. In the second part of this thesis, we deal with a Dirichlet to Neumann problem arising in a model for water waves. The system is described by a diffusion equation in a slab of fixed height, containing a weight that depends on a parameter a belonging to (-1,1). The top of the slab is endowed with a 0-Neumann condition, while on the bottom we have a Dirichlet datum and an equation involving a smooth nonlinearity. The system can also be reformulated as a nonlocal problem on the component endowed with the Dirichlet datum, by defining a suitable Dirichlet to Neumann operator. First, we prove a Liouville theorem that establishes the one dimensional symmetry of stable solutions, provided that a control on the growth of the energy associated with the problem is satisfied. As a consequence, we obtain the 1D symmetry of stable solutions to our problem in dimension 2. For n=3, we establish sharp energy estimates for both the energy minimizers and the monotone solutions, deducing the 1D symmetry of these classes of solutions, by an application of our Liouville theorem. Concerning this problem, we also investigate the nature of the associated Dirichlet to Neumann operator. First, we deduce its expression as a Fourier operator, which was known only in the case a=0. This result highlights the mixed nature of the operator, which is nonlocal, but not purely fractional. To better understand the dual behaviour of the operator, we provide a G-convergence result for an energy functional associated with the operator. Specifically, as a G-limit of our energy functional we find a mere interaction energy when a is greater than 0, and the classical perimeter when a is smaller or equal than 0. We point out that the threshold a=0 that we obtain here, as well as the G-limit behaviour for nonpositive values of a, is common to other nonlocal problems treated in the literature. On the contrary, the limit functional that we obtain in the other case appears to be new and structurally different from other nonlocal energy functionals that have been investigated in the literature.
Mi tesis se encaja en el estudio de las EDPs elípticas. Está dividida en dos partes: la primera trata una ecuación no-lineal con el p-Laplaciano, la segunda de un problema no-local. En la primera parte, estudiamos la regularidad de las soluciones estables de una ecuación no lineal con el p-Laplaciano en un dominio acotado. Esta ecuacion es la versión no-lineal de la ámpliamente estudiada ecuacion semilineal con el Laplaciano. Cabré, Figalli, Ros-Oton, y Serra han demostrado recientemente que las soluciones estables de las ecuaciones semilineales son acotadas, y por tanto regulares, hasta la dimensión 9. Este resultado es optimal. En el caso del p-Laplaciano, la regularidad de las soluciones estables se conjetura de ser cierta hasta una dimension critica y, de hecho, se conocen ejemplos de soluciones no acotadas cuando la dimension llega al valor critico. Además, se ha demostrado que en el caso radial o assumiendo hipótesis fuertes sobre la no-linealidad las soluciones estables son acotadas hasta la dimension critica. En el primer capítulo, demostramos que las soluciones estables son acotadas, bajo una nueva condición en n y p, que es optimal en el caso radial, y más restrictiva en el caso general. Esta investigación mejora conocidos resultados del tema y es el primer ejemplo, para el p-Laplaciano, de un método que produce un resultado para el caso general y un resultado optimal en el caso radial. En la primera parte, nos ocupamos también de las desigualdades funcionales del tipo Hardy y Sobolev sobre hipersuperfícies del espacio Euclideo, todas conteniendo un término de curvatura media. Nuestra motivación proviene de varias apliaciones que tienen estas desigualdades en el estudio de estimaciones para las soluciones estables. En detalle, damos una demostración simple de la conocida desigualdad de Michael-Simon y Allard, obtenemos dos formas nuevas de la desigualdad de Hardy sobre hipersuperfícies, y otra desigualdad de Hardy-Poincaré. En la segunda parte, nos ocupamos de un problema de Dirichlet-Neumann que emerge de un modelo para las ondas en el agua. El sistema se describe con una ecuación de difusión en una tira de altura fija, que contiene un parámetro a en (-1,1). La parte superior de la tira es dotada de una condicion 0 de Neumann, mientras en la parte inferior tenemos un dato de Dirichlet y una ecuación con una nonlinearidad regular. Este problema puede ser reformulado como una ecuación no-local sobre la componente dotada del dato de Dirichlet, definiendo un operador de Dirichlet-Neumann apropiado. Primero, demostramos un teorema del tipo Liouville, que garantiza la simetría unidimensional de las soluciones monótonas, asumiendo un control sobre el crecimiento de la energía asociada. Como consecuencia, obtenemos la simetría 1D de las soluciones estables en dimension 2. Para n=3, obtenemos estimaciónes optimales de la energía para las soluciones que minimizan la energía y para las soluciones monótonas. Estas estimaciones nos conducen a la simetría 1D de estas clases de soluciones, aplicando nuestro teorema del tipo Liouville. Relativo a este problema, estudiamos también la naturaleza del operador de Dirichlet-Neumann. Primero, deducimos su expresión como operador de Fourier, que anteriormente solo se conocía para a=0. Este resultado evidencia la naturaleza del operador, que es no-local pero no puramente fraccionaria. Estudiamos en profundidad este comportamiento mixto del operador a través del estudio de la G-convergencia de un funcional energía asociado al operador. Demostramos la G-convergencia de nuestro funcional a un límite que corresponde a una energía de interacción pura cuando a en (0,1) y al perímetro clásico cuando a en (-1,0]. El límite a=0, así como el G-límite para el régimen a en (-1,0], es común a otros problemas no-locales tratados en la literatura. Al contrario, el funcional límite en el régimen puramente no-local es nuevo y diferente a otros funciona
Questa tesi si occupa di equazioni differenziali alle derivate parziali di tipo ellittico. È divisa in due parti: la prima riguarda un’equazione nonlineare per il p-Laplaciano, mentre la seconda è incentrata su un problema nonlocale, che può essere formulato per mezzo di un operatore di Dirichlet-Neumann collegato con il Laplaciano frazionario. Nella prima parte, studiamo la regolarità delle soluzioni stabili dell’equazione nonlineare per il p-Laplaciano dove W è un dominio limitato, p 2 (1,+¥) e f è una nonlinearità C1. Questa equazione è la versione nonlineare dell’equazione semilineare 􀀀������������Du = f (u) in un dominio limitato W Rn, che è stata ampiamente studiata in letteratura. Molto recentemente, Cabré, Figalli, Ros-Oton, e Serra [38] hanno dimostrato che le soluzioni stabili delle equazioni semilineari sono limitate, e quindi regolari, in dimensione n 9. Questo risultato è ottimale, dato che esempi di soluzioni illimitate e stabili sono noti in dimensione n 10. Inoltre, i risultati in [38] forniscono una risposta completa ad un annoso problema aperto, proposto da Brezis e Vázquez [25], sulla regolarità delle soluzioni estremali dell’equazione 􀀀������������Du = l f (u). Queste ultime sono infatti esempi non banali di soluzioni stabili di equazioni semilineari, che possono essere limitate o illimitate in dipendenza della dimensione n, del dominio W, e della nonlinearità f . In questa tesi studiamo la limitatezza delle soluzioni stabili di (0.4), che si congettura essere vera fino alla dimensione n < p + 4p/(p 􀀀������������ 1). Sono infatti noti esempi di soluzioni stabili e illimitate quando n p + 4p/(p 􀀀������������ 1), anche quando il dominio è la palla unitaria. Inoltre, nel caso radiale o assumendo ipotesi forti sulla nonlinearità, è stato dimostrato che le soluzioni stabili di (0.4) sono limitate quando n < p + 4p/(p 􀀀������������ 1). Nel Capitolo 1 della tesi dimostriamo una nuova stima L¥ a priori per le soluzioni stabili di (0.4), assumendo una nuova condizione su n e p, che è ottimale nel caso radiale e più restrittiva nel caso generale. Il nostro risultato migliora ciò che è noto in letteratura e ed è il primo esempio di tecnica che produce sia un risultato nel caso non radiale sia il risultato ottimale nel caso radiale. Per ottenere questo risultato estendiamo al caso del p-Laplaciano una tecnica sviluppata da Cabré [30] per il caso classico del problema, con p = 2. La strategia si basa su una disuguaglianza di Hardy sugli insiemi di livello della soluzione, combinata con una disuguaglianza di tipo geometrico per le soluzioni stabili di (0.4). Nella prima parte della tesi ci occupiamo anche di disuguaglianze funzionali di tipo Hardy e Sobolev, su ipersuperfici dello spazio euclideo. Nel fare ciò siamo motivati dalle varie applicazioni di questo tipo di risultati allo studio di stime a priori per le soluzioni stabili, sia nel caso semilineare che nel caso nonlineare ...

Les symétries géométriques en usage en physique nucléaire sont assez peu variées, essentiellement la symétrie de l’ellipsoïde triaxial. On propose donc une méthode rigoureuse permettant d’étudier l’évolution et la possibilité de l’existence de symétries nouvelles dont la symétrie tétraédrique. Le formalisme de l’équation de SCHRÖDINGER est replacé dans le cadre des espaces de RIEMANN. Ce formalisme est utilisé dans le contexte du noyau de l’atome où l’on applique la théorie du champ moyen alliée à l’approximation adiabatique. Le noyau est le siège de deux catégories de mouvements adiabatiquement séparés, le mouvement rapide des nucléons dans le champ moyen, et le mouvement collectif modifiant lentement le champ moyen. Le second est régi par une équation de SCHRÖDINGER collective qui prend place dans un espace dont la métrique est donnée par le tenseur de masse. L’étude de la géométrie du noyau est alors calculable à l’aide de deux grands programmes développés dans le cadre de la thèse
The geometrical symmetries used in nuclear physics are not very diversified, essentially the symmetry of the triaxial ellipsoid. One proposes therefore a rigourous method allowing to study the temporal evolution and the possibility of the existence of new symmetries among them the tetrahedral symmetry. The formalism of SCHRÖDINGER equation is reformulated in the framework of RIEMANN’s spaces. This formalism is used in the context of the atomic nucleus where one applies the mean-field theory combined with the adiabatic approximation. The nucleus is the terrain of two types of motions adiabatically separated, the quick motion of the nucleons in the mean-field and the collective motion modifying slowly the meanfield. The second one is governed by a collective SCHRÖDINGER equation written down in a space whose metric is given by the mass tensor. The study of the nucleus geometry is then computable with the help of two big programs developped within the thesis

Questa tesi è incentrata sullo studio di equazioni differenziali alle derivate parziali di tipo ellittico. La prima parte della tesi riguarda la regolarità delle soluzioni stabili per un'equazione nonlineare con il p-Laplaciano, in un dominio limitato dello spazio Euclideo. La tecnica è basata sull'uso di disuguaglianze di tipo Hardy-Sobolev su ipersuperfici, del quale viene approfondito lo studio. Nella seconda parte viene preso in esame un problema nonlocale di tipo Dirichlet-Neumann. Studiamo la simmetria unidimensionale di alcune sottoclassi di soluzioni stabili, ottenendo risultati in dimensione n=2, 3. Inoltre, studiamo il comportamento asintotico dell'operatore associato a questo problema nonlocale, usando tecniche di Γ-convergenza.
This thesis deals with the study of elliptic PDEs. The first part of the thesis is focused on the regularity of stable solutions to a nonlinear equation involving the p-Laplacian, in a bounded domain of the Euclidean space. The technique is based on Hardy-Sobolev inequalities in hypersurfaces involving the mean curvature, which are also investigated in the thesis. The second part concerns, instead, a nonlocal problem of Dirichlet-to-Neumann type. We study the one-dimensional symmetry of some subclasses of stable solutions, obtaining new results in dimensions n=2, 3. In addition, we carry out the study of the asymptotic behaviour of the operator associated with this nonlocal problem, using Γ-convergence techniques.

The purpose of this study was to describe and analyze IntimatePartner Violence (IPV). How does contemporary science illustrate men as victimsand women as perpetrators in these relationships? Ten articles were presentedand analyzed in a systematic literature study. The results show that men beingabused by their female intimate partner, do exist and that they in many ways doconform to abused women. There are many underlying causes to the violence inclose relationships. There are also many shapes and degrees in violence and inIntimate Partner Violence (IPV). Furthermore, Intimate Partner Violence (IPV) exhibitssymmetry in socio-demographic characteristics, such as gender and ethnicity. Thefindings also points out that Common Couple Violence (CCV) are a much morecommon form of violence than Intimate Terrorism (IT) and that both forms areused by men and women. Finally, violence is ambiguous, includes many aspectsand is not easy to explain among cultural values, norms and social contexts.Still, violence is a universal human issue which demands social interventions.

Les symétries géométriques jouent un rôle important dans la compréhension de la stabilité de tout système physique. En structure nucléaire, elles sont reliées à la forme du champ moyen utilisé pour décrire les propriétés des noyaux atomiques. Dans le cadre de cette thèse, nous avons utilisé les prédictions obtenues avec l'aide du Hamiltonien du champ moyen nucléaire avec le potentiel de Woods-Saxon Universel pour étudier les effets des symétries dites de « Haut-Rang ». Ces symétries ponctuelles mènent à des dégénérescences des états nucléaires d’ordre 4. Il est prédit que la symétrie tétraédrique influence la stabilité des noyaux proches des nombres magiques tétraédriques [Z,N]=[32,40,56,64,70,90-94,136]. Nous avons sélectionné la région des Terres-Rares proche du noyau doublement magique tétraédrique 154Gd pour notre étude. Dans cette région, il existe des structures de parité négative qui sont mal comprises. Or la symétrie tétraédrique, en tant que déformation octupolaire non-axiale, brise la symétrie par réflexion et doit produire des états de parité négative. Après une étude systématique des propriétés expérimentales des noyaux de la région, nous avons sélectionné le 156Gd comme objet de notre étude des modes d’excitation octupolaire. Nous avons utilisé les probabilités réduites de transition gamma pour discerner ces différents modes. Pour atteindre cet objectif, nous avons réalisé trois expériences de spectroscopie gamma à l’ILL de Grenoble avec les détecteurs EXILL et GAMS afin de mesurer les durées de vie et les intensités des transitions gamma des états candidats. L'analyse de nos résultats montre que notamment la forme tétraédrique aide à comprendre les probabilités des transitions dipolaires. Ce résultat ouvre de nouvelles perspectives expérimentales et théoriques
Geometrical symmetries play an important role in the understanding of all physical systems. In nuclear structure they are linked to the shape of the mean-field used to describe the atomic nuclei properties. In the framework of this thesis, we have used the predictions obtained with the help of the nuclear mean-field Hamiltonian with the Universal Woods-Saxon potential to study the effects of the so-called “High-Rank” symmetries. These point-group symmetries lead to a nuclear state degeneracy of the order of 4. It is predicted that the tetrahedral symmetry affects the stability of nuclei close to the tetrahedral magic numbers [Z,N]=[32,40,56,64,70,90-94,136]. We have selected the Rare-Earth region close to the tetrahedral doubly magic nucleus 154Gd for our study. In this region, there exists negative parity structures poorly understood. Yet the tetrahedral symmetry, as related to a non-axial octupole deformation, breaks the reflection symmetry and leads to the negative parity states. Following a systematics of experimental properties of the nuclei in this region, we have selected 156Gd as the object of our study for the octupole excitation modes. We have used the reduced transitions probabilities to discriminate between these modes. To achieve this goal, we have performed three gamma spectroscopy experiments at the ILL in Grenoble with the EXILL and GAMS detectors to measure the lifetimes and the gamma transition intensities from the candidate states. The analysis of our results shows that including the tetrahedral shape helps to understand the dipole transition probabilities. This result will open new experimental and theoretical perspectives

This thesis focus on the extension of the Parisi full replica symmetry breaking solution to the Ising spin glass on a random regular graph. We propose a new martingale approach, that overcomes the limits of the Parisi-Mézard cavity method, providing a well-defined formulation of the full replica symmetry breaking problem in random regular graphs. We obtain a variational free energy functional, defined by the sum of two variational functionals (auxiliary variational functionals), that is an extension of the Parisi functional of the Sherrington-Kirkpatrick model. We study the properties of the two variational functionals in detailed, providing representation through the solution of a proper backward stochastic differential equation, that generalize the Parisi partial differential equation. Finally, we define the order parameters of the system and get a set of self-consistency equations for the order parameters and free energy.

碩士
國立臺灣科技大學
資訊工程系
93
Recently, Su and Chou presented an efficient point symmetry--based K--means algorithm. Extending their point symmetry--based K--means algorithm, this paper presents a novel line symmetry--based K--means algorithm for clustering the data set with line symmetry property. Based on some real data sets, experimental results demonstrate that our proposed line symmetry--based K--means algorithm is rather encouraging.

This thesis has two parts. The first part revolves around certain theorems related to an uncertainty principle and quasi-analyticity. In contrast, the second part reflects a different mathematical theme, focusing on the classical problem of $L^p$ boundedness of spherical maximal function on the Heisenberg group. The highlights of the first part are as follows: An uncertainty principle due to Ingham (proved initially on $\R$) investigates the best possible decay admissible for the Fourier transform of a function that vanishes on a nonempty open set. One way to establish such a result is to use a theorem of Chernoff (proved originally on $\mathbb{R}^n$), which provides a sufficient condition for a smooth function to be quasi-analytic in terms of a Carleman condition involving powers of the Laplacian. In this part of this thesis, we aim to prove various analogues of theorems of Ingham and Chernoff in different contexts such as the Heisenberg group, Hermite and special Hermite expansions, rank one Riemannian symmetric spaces and Euclidean space with Dunkl setting. More precisely, we prove various analogues of Chernoff's theorem for the full Laplacian on the Heisenberg group, Hermite and special Hermite operators, Laplace-Beltrami operators on rank one symmetric spaces of both compact and non-compact type, and Dunkl Laplacian. The main idea is to reduce the situation to the radial case by employing appropriate spherical means or spherical harmonics and then to apply Chernoff type theorems to the radial parts of the operators indicated above. Using those Chernoff type theorems, we then show several analogues of Ingham's theorem for the spectral projections associated with those aforementioned operators. Furthermore, we provide examples of compactly supported functions with Ingham type decay in their spectral projections, demonstrating the sharpness of Ingham's theorem in all of the relevant contexts mentioned above. In this second part of this thesis, we investigate the $L^p$ boundedness of the lacunary maximal function $ M_{\Ha}^{lac} $ associated to the spherical means $ A_r f$ taken over Koranyi spheres on the Heisenberg group. Closely following an approach used by M. Lacey in the Euclidean case, we obtain sparse bounds for these maximal functions leading to new unweighted and weighted estimates. The key ingredients in the proof are the $L^p$ improving property of the operator $A_rf$ and a continuity property of the difference $A_rf-\tau_y A_rf$, where $\tau_yf(x)=f(xy^{-1})$ is the right translation operator.

碩士
國立臺灣科技大學
資訊工程系
92
Based on the recently published elegant point symmetry distance (PSD) measure, this paper presents a novel PSD measure, namely symmetry similarity level (SSL) operator for K--means algorithm. Our proposed modified point symmetry-based K-means (MPSK) algorithm is more robust than the previous PSK algorithm by Su and Chou. Not only our proposed MPSK algorithm is suitable for the symmetrical intra--clusters as the PSK algorithm does, our proposed MPSK algorithm is also suitable for the symmetrical inter-clusters. In addition, this paper presents two speedup strategies to reduce the time required in our proposed MPSK algorithm. Experimental results demonstrate the significant execution-time improvement and the extension to the symmetrical inter-clusters of our proposed MPSK algorithm when compared to the previous PSK algorithm.

Documentos apresentados no âmbito do reconhecimento de graus e diplomas estrangeiros
Equation of state (EOS) of dense matter has been constrained from the experimental data available on the properties of finite nuclei and neutron stars. Towards this purpose, a diverse set of nuclear energy density functionals based on relativistic and non-relativistic mean field models have been employed. These EOSs are so chosen that they are consistent with the bulk properties of the finite nuclei. The values of various nuclear matter parameters which predominantly govern the behaviour of the EOS are determined through their correlations with the properties of the neutron stars such as radii, tidal deformability and maximum mass of the neutron stars. The nuclear matter parameters considered are incompressibility, symmetry energy and their density derivatives which appear in the expansion of the EOS around the saturation density. The radii and tidal deformability of the neutron star with the canonical mass display strong correlations with the linear combinations of slopes of the incompressibility and symmetry energy coefficients. Similar correlations with the curvature of the symmetry energy coefficient are also obsvered indicating that the properties of the neutron stars are sensitive to the high density behaviour of the symmetry energy. It is also shown that the giant resonances in nuclei are instrumental in limiting the tidal deformability parameter and the radius of a neutron star in somewhat narrower bounds. The outcomes of the present thesis is important in view of the fact that the accurate values of the various neutron star observables as considered are expected to be available in near future.