Analyse transitoire des modèles markoviens des systémes tolérants aux fautes avec réparation différée.

La tesis aborda el análisis transitorio de modelos Markovianos de sistemas tolerantes a fallos con reparación diferida. Se consideran dos medidas definidas sobre cadenas de Markov a tiempo continuo con tasas de recompensa asociadas a los estados: la tasa de recompensa esperada en el instante t y la tasa media de recompensa esperada en el intervalo de tiempo [0, t]. Casos particulares importantes de esas dos medidas son la no-fiabilidad, la disponibilidad en el instante t y la disponibilidad de intervalo esperada. La tesis desarrolla un método numérico para el cálculo de ambas medidas con error arbitrariamente pequeño, denominado aleatorización regenerativa partida. Una ventaja importante del método es su estabilidad numérica. También se desarrolla un método numéricamente estable, la aleatorización regenerativa partida acotante, para el cálculo de cotas para un caso particular de la la tasa de recompensa esperada en el instante t que incluye la no-fiabilidad y cotas para ella. El coste computacional de los métodos es comparado con el de otros métodos basados en la aleatorización. La aleatorización regenerativa partida puede ser mucho menos costosa que los demás métodos para t grande y, cuando la relación entre la máxima y la mínima tasa de salida desde los estados con reparación no es muy elevada, permite el análisis en tiempos de CPU razonables de cadenas de Markov con muchos estados. La aleatorización regenerativa partida acotante tiene un coste computacional relativo muy bajo y proporciona cotas ajustadas, permitiendo el análisis en tiempos de CPU razonables de cadenas de Markov con muchísimos estados. En combinación con técnicas de acotación, los métodos desarrollados permiten el análisis numérico en tiempos de CPU razonables de modelos Markovianos de sistemas tolerantes a fallos con reparación diferida con un número muy elevado de componentes

Embedded Line Scan Image Sensors: The Low Cost Alternative for High Speed Imaging

In this paper we propose a low-cost high-speed imaging line scan system. We replace an expensive industrial line scan camera and illumination with a custom-built set-up of cheap off-the-shelf components, yielding a measurement system with comparative quality while costing about 20 times less. We use a low-cost linear (1D) image sensor, cheap optics including a LED-based or LASER-based lighting and an embedded platform to process the images. A step-by-step method to design such a custom high speed imaging system and select proper components is proposed. Simulations allowing to predict the final image quality to be obtained by the set-up has been developed. Finally, we applied our method in a lab, closely representing the real-life cases. Our results shows that our simulations are very accurate and that our low-cost line scan set-up acquired image quality compared to the high-end commercial vision system, for a fraction of the price.Comment: 2015 International Conference on Image Processing Theory, Tools and Applications (IPTA

A generalized method for the transient analysis of Markov models of fault-tolerant systems with deferred repair

Randomization is an attractive alternative for the transient analysis of continuous time Markov models. The main advantages of the method are numerical stability, well-controlled computation error and ability to specify the computation error in advance. However, the fact that the method can be computationally expensive limits its applicability. Recently, a variant of the (standard) randomization method, called split regenerative randomization has been proposed for the efficient analysis of reliability-like models of fault-tolerant systems with deferred repair. In this paper, we generalize that method so that it covers more general reward measures: the expected transient reward rate and the expected averaged reward rate. The generalized method has the same good properties as the standard randomization method and, for large models and large values of the time t at which the measure has to be computed, can be significantly less expensive. The method requires the selection of a subset of states and a regenerative state satisfying some conditions. For a class of continuous time Markov models, class C'_2, including typical failure/repair reliability models with exponential failure and repair time distributions and deferred repair, natural selections for the subset of states and the regenerative state exist and results are available assessing approximately the computational cost of the method in terms of “visible” model characteristics. Using a large model class C'_2 example, we illustrate the performance of the method and show that it can be significantly faster than previously proposed randomization-based methods.Preprin

A generalized method for the transient analysis of Markov models of fault-tolerant systems with deferred repair

Randomization is an attractive alternative for the transient analysis of continuous time Markov models. The main advantages of the method are numerical stability, well-controlled computation error, and ability to specify the computation error in advance. However, the fact that the method can be computationally expensive limits its applicability. Recently, a variant of the (standard) randomization method, called split regenerative randomization has been proposed for the efficient analysis of reliability-like models of fault-tolerant systems with deferred repair. In this article, we generalize that method so that it covers more general reward measures: the expected transient reward rate and the expected averaged reward rate. The generalized method has the same good properties as the standard randomization method and, for large models and large values of the time t at which the measure has to be computed, can be significantly less expensive. The method requires the selection of a subset of states and a regenerative state satisfying some conditions. For a class of continuous time Markov models, class C'_2, including typical failure/repair reliability models with exponential failure and repair time distributions and deferred repair, natural selections for the subset of states and the regenerative state exist and results are available assessing approximately the computational cost of the method in terms of “visible” model characteristics. Using a large model class C'_2 example, we illustrate the performance of the method and show that it can be significantly faster than previously proposed randomizationbased methods.Postprint (published version

Etude des effets neuroprotecteurs des stilbènes de la vigne sur la maladie de Parkinson

Parkinson’s disease is one of the most spread neurodegenerative diseases in the world. Post mortem analyses have put in evidence small inclusion bodies in patient’s brain, composed of α-synuclein fibrils. Several studies attempted then to identify compounds that could inhibit α-synuclein aggregation, as its aggregation is linked to its toxicity. Still, numerous active compounds need to be identified in order to put on relief shared active structures that could lead to a potent drug design. Stilbenes are phenolic compounds that often display interesting health-related biological activities. In this study, the anti-aggregative behavior of stilbenes monomers (resveratrol, piceatannol) and oligomers such as ampelopsin and isohopeaphenol was assessed. The results put on evidence stilbene propensity to inhibit α-synuclein aggregation and provide an insight into their inhibition mechanisms.La maladie de Parkinson est l’une des plus répandue dans le monde. Des analyses post mortem ont mis en évidences des inclusions dans les cerveaux des patients, composées d’α-synucléine. Plusieurs études ont visé à identifier des composés capables d’inhiber l’agrégation de cette protéine, étant donné que cette agrégation est liée à sa toxicité. Néanmoins, de nombreux composés restent encore à être identifiés afin de mettre en évidence des structures moléculaires actives partagées qui pourrait mener à la synthèse d’un principe actif. Les stilbènes sont des composés phénoliques démontrant régulièrement des activités biologiques intéressantes pour la santé. Dans cette étude, nous étudions le comportement anti-agrégatif des stilbènes monomériques (resvératrol, picéatannol) et oligomèriques (ampélopsine, viniférine, et isohopeaphénol). Les résultats présentés mettent en évidence la capacité des stilbènes à inhiber l’agrégation de l’α-synucléine et fournissent des éléments pour comprendre ce mécanisme

El estrecho de Gibraltar: protección internacional y nacional de su medio ambiente marino

Esta tesis tiene el objeto de resaltar el marco jurídico internacional y nacional aplicado en la zona del estrecho de Gibraltar, con el propósito de poner, después, en relieve la ausencia de un marco jurídico adecuadamente protector de su medio ambiente marino, que convenga a un estrecho de su índole. Sin embargo el régimen del estrecho, regido por los artículos 37 y 38 del CNUDM, hace que el nacimiento de un eventual marco jurídico sea reconocido por el Derecho internacional y obviamente bajo su auspicio. Este reto supone la implicación de los pilares fundamentales como RU, los Estados usuarios y las ONGs locales junto a los Estados ribereños: España y Marruecos y otros actores a saber la colonia británica de Gibraltar, la UE y la OMI. Sin desde luego omitir los intereses económicos que suelen ir en contra de la protección del medio ambiente en general y marino en particular.This thesis witch title is “ Strait of Gibraltar: international and notional protection of its marine environment”, is intended to highlight the international and national legal framework applied in the Strait of Gibraltar area, with the aim to focus attention on the absence of a properly protective legal framework for the marine environment of a Strait of its nature. However, the regime of the Strait, governed by articles 37 and 38 of UNCLOS, makes the birth of a possible legal framework shall be recognized by international law and under its auspices. This challenge entails the involvement of key pillars such as UK, user States and local NGOs, next to the States bordering: Spain and Morocco and other actors, namely the British colony of Gibraltar, the EU and IMO. Without of course omit the economic interests that tend to go against the protection of the environment in general and marine in particular.Tesis Univ. Jaén. Departamento de Derecho Público y Común Europeo. Leída el 13 de julio de 2017

LA CHIMIE VERTE

La chimie verte est un ensemble de principes qui ont pour but de réduire ou d’éliminer l’utilisation ou la génération de substances dangereuses émanant des processus de design, de fabrication et d’application de produits chimiques. Ces principes, au nombre de 12 “Les 12 Principes de la Chimie Verte”, sont décrits ici et des exemples sont donnés pour que nos chercheurs, industriels et universitaires, l’adoptent comme une ligne de conduite au laboratoire, une règle d’éthique voire même un “Sermon d’Hippocrate” pour les Chimistes. Cet article a aussi pour but d’attirer l’attention des personnes travaillant dans des laboratoires sur les concepts suivants : minimiser les déchets à la source ; maximiser l’efficacité de l’atome ; réduire l’utilisation de réactifs toxiques ; conserver l’énergie et accroître l’utilisation de ressources renouvelables. Le Dr. Terry Collins, Professeur de Chimie à Carnegie Mellon University, avait l’habitude de dire:“La chimie doit jouer un rôle important pour maintenir une civilisation durable sur terre”. Pour montrer cela, des exemples de composé verts sont présentés et discutés dans cet article