Le concept de quasi-espèce, introduit par Manfred Eigen dans les années 70, décrit l'état d'équilibre d'une population subissant des forces de mutation et sélection. La plupart des modèles classiques présentant un phénomène de quasi-espèce sont déterministes et considèrent une population de taille infinie. L'objectif de cette thèse est d'étudier plusieurs modèles stochastiques, dont la taille de la population est finie, afin de montrer que le phénomène de la quasi--espèce est aussi présent dans ces modèles comme dans le modèles déterministes. Nous étudions en détail les modèles de Galton-Watson, Wright-Fisher et Moran. Nous confirmons que les trois modèles présentent un phénomène de quasi--espèce, et que la distribution de la quasi--espèce est la même pour les trois modèles, ainsi que pour le modèle original d'Eigen. De plus, nous décrivons explicitement la distribution de cette quasi--espèce pour le paysage de fitness à un pic, ainsi que pour des fonctions de fitness qui ne dépendent que de la distance de Hamming à la master sequence. / Manfred Eigen introduced the concept of quasispecies in the early 70s, in order to describe the steady--state distribution of a population subject to mutation and selection forces. Most classical models showing a quasispecies phenomenon are deterministic and deal with a population of an infinite size. The aim of this thesis is to study several stochastic and finite--population models, and to show that a quasispecies phenomenon arises in these models too. We study in detail the Galton--Watson, Wright--Fisher and Moran models. We confirm that a quasispecies phenomenon is present in the three models, and that the distribution of this quasispecies is common to all three models as well as to Eigen's original model. Moreover, we describe explicitly the distributionof the quasispecies for the sharp peak landscape, as well as for fitness functions which depend only on the Hamming distance to the master sequence.

The rapid development of Internet introduces a new set of challenging problem regarding security. To prevent unauthorized copying of digital production from distributing is one of the significant problems. Digital watermarking is a potential method for protecting the ownership rights on digital audio, image and video data. An attack succeeds in defeating a watermarked article if it impairs the watermarking information beyond acceptable limits while maintaining the perceptual quality of the attacked article. Namely, attacks on digital watermarked article must consider both watermarking information survival and the distortion of the attacked stego-media. Current attack benchmarks do not exploit as much knowledge of the watermarked image as possible, also they do not consider the distortion of the attacked stego-media. In this paper, various attacks on digital watermarking have been investigated, and a categorization of different attacks was roughly given; Besides, an Eigen-image-based (ED-based) attack is proposed to deliberately impair the watermarking information without excessively distorting the attacked stego-media, that is not currently included in those benchmark tools.

<p>We present a technique to identify deviating systems among a group of systems in a</p><p>self-organized way. A compressed representation of each system is used to compute similarity measures, which are combined in an affinity matrix of all systems. Deviation detection and clustering is then used to identify deviating systems based on this affinity matrix.</p><p>The compressed representation is computed with Principal Component Analysis and</p><p>Kernel Principal Component Analysis. The similarity measure between two compressed</p><p>representations is based on the angle between the spaces spanned by the principal</p><p>components, but other methods of calculating a similarity measure are suggested as</p><p>well. The subsequent deviation detection is carried out by computing the probability of</p><p>each system to be observed given all the other systems. Clustering of the systems is</p><p>done with hierarchical clustering and spectral clustering. The whole technique is demonstrated on four data sets of mechanical systems, two of a simulated cooling system and two of human gait. The results show its applicability on these mechanical systems.</p>

Most watermark-removal methods treat watermarks as noise and apply denoising approaches to remove them. However, denoising methods remove not only this watermark energy, but also some of the energy of the original image. A trade-off therefore exists: if not enough of the watermark energy is removed, then the watermark will still be detected, but if too much is removed, the image quality will be noticeably poor. To solve this problem, the relationship among the energies of the original image, the watermark and the watermarked image is initially determined using stochastic models. Then, the energy of the watermark is estimated using just-noticeable-distortion (JND). Finally, the watermark energy is removed from the watermarked image based on the energy distribution of its Eigen-images. The experimental results show that the proposed approach yields a mean peak signal-to-noise ratio (PSNR) of the predicted images that is 2.2dB higher than that obtained using the adaptive Wiener filter, and a mean normalized correlation (NC) value of the extracted watermarks that is 0.27 lower than that obtained using the adaptive Wiener filter. In removing watermark energy from 100 randomly selected watermarked images in which watermarks were embedded using the ¡¥Broken Arrows (BA)¡¦ algorithm proposed for the second Breaking Our Watermarking System (BOWS-2) contest, the mean PSNR of 100 predicted images is 24.1dB and the proposed approach successfully removed watermarks from 90 of these images. This result exceeds the minimum requirement of PSNR 20dB for the BOWS-2 contest. Clearly, the proposed approach is a very effective watermark-removal approach for removing watermarks.

Eigen fuzzy sets of fuzzy relation can be used for the estimation of highest and lowest levels of involved variables when applying max-min composition on fuzzy relations. By the greatest eigen fuzzy sets (set which can be greater anymore) maximum membership degrees of any fuzzy set can be found, with the help of least eigen fuzzy set (set which can be less anymore) minimum membership degrees of any fuzzy sets can be found as well.The lowest and highest level, impact or e ffect of anything can be found by applying eigen fuzzy set theory. The implicational aspect of this research study is medical and customer satisfaction level measurement. By applying methods of eigen fuzzy set theory the e ffectiveness of medical cure and customer satisfaction can be found with high precision.

We present a technique to identify deviating systems among a group of systems in a self-organized way. A compressed representation of each system is used to compute similarity measures, which are combined in an affinity matrix of all systems. Deviation detection and clustering is then used to identify deviating systems based on this affinity matrix. The compressed representation is computed with Principal Component Analysis and Kernel Principal Component Analysis. The similarity measure between two compressed representations is based on the angle between the spaces spanned by the principal components, but other methods of calculating a similarity measure are suggested as well. The subsequent deviation detection is carried out by computing the probability of each system to be observed given all the other systems. Clustering of the systems is done with hierarchical clustering and spectral clustering. The whole technique is demonstrated on four data sets of mechanical systems, two of a simulated cooling system and two of human gait. The results show its applicability on these mechanical systems.

Proefschrift Universiteit Maastricht. / Met lit. opg. - Met samenvatting in het Nederlands en Bulgaars.

En el campo de la preservación de bienes muebles, la consolidación de madera es un tratamiento extremo, aplicado cuando ningún otro medio es capaz de garantizar su estabilidad. En general, los restauradores estiman: el nivel de deterioro, la necesidad de consolidar y el resultado del tratamiento, empíricamente o con la ayuda de imágenes del interior del objeto. Este proceder se trasluce en estudios de diagnóstico, en reportes de intervención o en publicaciones especializadas, donde se caracteriza el deterioro en términos subjetivos como: ataque severo, avanzado estado de deterioro, mal estado, etc. En apariencia este hecho puede resultar poco relevante; sin embargo, cuando se desea tomar como referencia los tratamientos de otros profesionales o si la cantidad de madera a intervenir es importante, la valoración del deterioro y del resultado del tratamiento variará. Esto muestra la importancia de contar con un método que evalúe objetivamente el ataque y la consolidación. En la presente tesis, se abordó este problema y se concluyó que la frecuencia fundamental permite, por un lado, discriminar niveles de deterioro; por otro lado, determinar el efecto de la consolidación con un buen grado de fiabilidad: R2=0,80. Como resultado paralelo, destaca la formulación de una ecuación desarrollada por el autor de esta tesis, para calcular el volumen máximo de solución requerida para consolidar, por inmersión, un volumen determinado de madera. / Benítez Telles, JE. (2010). Valoración del deterioro de la madera y la efectividad de su consolidación, midiendo la frecuencia fundamental de oscilación. Estudio experimental aplicado a la tablazón de los artesonados de la iglesia de San Francisco, Quito-Ecuador [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/8643

Comment caractériser le vivant dans le cadre scientifique tel qu'il se pratique et partant, identifier les contraintes et limites épistémiques qui rendent si délicate la théorisation d'un système matériel doté des propriétés que nous qualifions de vitales? Pour y répondre nous nous proposons de mener une enquête au coeur des propositions dedéfinitions de la vie, de leur inscription dans les thématiques qui courent tout au long de l'histoire de la pensée philosophique et scientifique. Elle introduira une analyse détaillée d'approches centrées sur des modèles théoriques du vivant, représentation globale de ces systèmes matériels originaux. / How to characterize the living beings in the scientific framework as it is practiced, and thereby, identify the constraints and epistemic limits which make tricky the theorization of a physical system which has the properties that we call vital? To answer we propose to conduct an investigation at the heart of various proposals of definitions of life, their connections with themes that runs throughout the history of philosophical and scientific thought. It will introduce a detailed analysis of some approaches centered on theoretical models of the living as global representation of these peculiar material systems.

This work focuses mainly on the resistance of members to flexural buckling according to Eurocode 3. The work provides the mathematical backgrounds to the equations and buckling curves presented in Eurocode 3. The work also, attempts to reveal how different imperfections influence the flexural buckling resistance which is demonstrated through Finite Element (FE) simulations. The work presents modeling and analysis on a steel column in ABAQUS 6.14. Linear and non-linear buckling analyses of the steel column, with the influence of imperfections, are implemented in this work. Specifically, the imperfections considered in this study are material plasticity, initial bow and residual stress. The influence of initial bow imperfection of 0.1% of the length of the column considering flexural buckling was found to be 45.28% of the Euler buckling load. The influence of residual stresses, with a magnitude of maximum about 13% in the flange and 35% in the web, of the yielding strength, on flexural buckling is about 31.9% of the design Euler buckling load. The combined effect of residual stress and initial bow imperfection on flexural buckling is about 45.34% of the design Euler buckling load.