Les chutes de blocs constituent un aléa naturel majeur dans les Alpes françaises en raison de leur probabilité d'occurrence spatiale et temporelle très élevée. Les forêts peuvent constituer une solution naturelle et efficace pour atténuer ce phénomène tout en protégeant les populations et leurs infrastructures. Cependant, ce service écosystémique peut être perturbé par d'autres aléas naturels comme les feux de forêts, susceptibles d'être plus fréquents et intenses dans le contexte actuel et futur de changements climatiques.Cette thèse propose ainsi d'évaluer les effets des incendies sur la capacité de protection des forêts contre les chutes de blocs dans les Alpes françaises.Une méthodologie pour évaluer la capacité de protection d'une forêt contre les chutes de blocs est d'abord développée et consiste à utiliser des simulations de propagation de chutes de blocs réalisées sur 3886 placettes forestières des Alpes françaises pour calculer trois indicateurs quantitatifs évaluant la réduction de la fréquence (BARI), de l'intensité (MIRI) et la réduction globale (ORPI) de l'aléa chutes de blocs dues à la présence d'une forêt. Ces indicateurs sont utilisés pour identifier les variables forestières prépondérantes pour évaluer la capacité de protection : la longueur boisée sur le versant, la surface terrière et le diamètre moyen. Les peuplements présentant une distribution hétérogène des diamètres et composés de plusieurs essences offrent généralement une meilleure protection que les peuplements monospécifiques et réguliers, soulignant ainsi l'influence de la diversité forestière. Cette thèse montre ainsi que les taillis présentent les capacités de protection les plus élevées, suivis par les futaies feuillues et les futaies mixtes ; les peuplements résineux venant en dernier.Les évolutions spatiales et temporelles des conditions climatiques favorables aux incendies, étudiées sur la période 1959-2015, révèlent un contraste majeur entre les Alpes du Sud qui ont connu une forte augmentation (en intensité, fréquence, durée et saisonnalité) surtout à haute altitude, et les Alpes du Nord, où une légère hausse est observée à basse altitude, mais aucune tendance significative n'est observée à haute altitude. Ces résultats sont ensuite utilisés pour définir trois types de feux (d'hiver, d'été moyen et d'été très sec) pour lesquels la mortalité post-incendie est étudiée à l'échelle de l'arbre et du peuplement forestier. Ces analyses montrent que seuls les feux d'été sont susceptibles d'affecter significativement les peuplements, en particulier à basse altitude où les peuplements feuillus (notamment les taillis) dominent.L’effet des incendies sur la capacité de protection des forêts est évalué en comparant les simulations de propagation de chutes de blocs sans feu aux simulations après chaque type de feu pour lesquelles les arbres avec une forte probabilité de mortalité post-feu ne sont pas pris en compte. Les valeurs de ORPI pour chaque placette forestière et chaque type de feu sont ainsi calculées et comparées au scénario de référence sans feu, permettant ainsi d'évaluer quantitativement la réduction de la capacité de protection. Les peuplements de basse altitude, soumis à des conditions climatiques plus chaudes et sèches, présentent des réductions de la capacité de protection après des feux d'été de l'ordre de 60 à 100 %. Il s'agit principalement de taillis et de futaies feuillues. À plus haute altitude, la réduction est de l'ordre de 30 à 65 %.En conclusion, ce travail de thèse propose une méthode originale pour quantifier la capacité de protection d'une forêt contre les chutes de blocs avant et après un incendie et alimente les connaissances sur ces deux aléas naturels et les risques associés. L'analyse multi-aléas conduite en fin de thèse permet d'appréhender les effets cascades potentiels à l'échelle du peuplement forestier et de quatre territoires bioclimatiquement homogènes des Alpes françaises. / Rockfalls are a major natural hazard in the French Alps due to their high probability of spatial and temporal occurrence. Forests constitute an efficient nature-based solution to mitigate this hazard while protecting human lives and assets. However, this ecosystem service may be disrupted by others natural hazards such as wildfires likely to be more frequent and intense in the current and future context of climate changes.This PhD thesis proposes to assess the effects of fires on the protection capability of forests against rockfalls in the French Alps.A methodology to evaluate the protection capability of a forest against rockfalls is first developed. It consists in modeling rockfalls propagations on 3886 forest plots taken in the French Alps to calculate three quantitative indicators that assess the reduction of the frequency (BARI), the intensity (MIRI) and the overall reduction (ORPI) of rockfalls due to the presence of a forest. These indicators are used to identify the predominant forest variables for assessing the protective effect: the length of forest along the slope, the basal area and the mean diameter. Forest stands with a heterogeneous distribution of diameters and made up of several tree species generally offer a better protection than monospecific and regular stands, thus underlining the influence of forest diversity. This work shows that coppices have the highest protection capabilities, followed by hight stands dominated by deciduous species and mixed stands; coniferous stands coming last.Spatio-temporal trends in fire weather in the French Alps are investigated over the period 1959-2015 and reveal a major contrast between Southern Alps which experienced a strong increase (in intensity, frequency, duration and seasonality) especially at high elevation, and Northern Alps, where a slight increase at low elevation and no significant trends at high elevation are observed. These results are then used to define three types of fires (winter, summer, and dry summer) for which post-fire tree mortality is studied at the tree and forest stands levels. These analyses show that only summer fires are likely to significantly affect the forest ecosystems, particularly at low elevations where deciduous stands (especially coppice) dominate.The effect of fires on the protection capabilities of forests is assessed by comparing rockfalls propagation simulations without fire to simulations after each type of fire in which the trees with a high post-fire mortality are not taken into account. The ORPI values for each forest plot and fire type are thus calculated and compared to the reference scenario without fire thus making it possible to quantitatively assess the reduction of the protection capabilities. Low elevation stands, subject to warmer and drier climatic conditions, show reductions of the protective effect in the range 60-100%. It mainly concerns coppices and deciduous stands. At high elevation, the reduction is in the range 30- 65%.In conclusion, this PhD thesis proposes an original method to quantify the protection capabilities of a forest against rockfalls before and after a fire and improve the knowledge of these two natural hazards and their associated risks. The multi-hazard analysis conducted at the end of the thesis makes it possible to understand the potential cascading effects in the main forest types and for four bioclimatically homogeneous territories of the French Alps.

A new approach to the evaluation of the reliability of electrical systems is presented. In this approach a Graph Trace Analysis based approach is applied to integrated system models and reliability analysis. The analysis zones are extended from the traditional power system functional zones. The systems are modeled using containers with iterators, where the iterators manage graph edges and are used to process through the topology of the graph. The analysis provides a means of computationally handling dependent outages and cascading failures. The effects of adverse weather, time-varying loads, equipment age, installation environment, operation conditions are considered. Sequential Monte Carlo simulation is used to evaluate the reliability changes for different system configurations, including distributed generation and transmission lines. Historical weather records and loading are used to update the component failure rates on-the-fly. Simulation results are compared against historical reliability field measurements. Given a large and complex plant to operate, a real-time understanding of the networks and their situational reliability is important to operational decision support. This dissertation also introduces using an Integrated System Model in helping operators to minimize real-time problems. A real-time simulation architecture is described, which predicts where problems may occur, how serious they may be, and what is the possible root cause. / Ph. D.

Submitted by Alexandra Cisotto Belline (alexandrabelline@yahoo.com.br) on 2016-06-14T19:42:18Z No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 14 06 2016.pdf: 8341218 bytes, checksum: 387a098a147e1b777b282c181b5bbe1c (MD5) / Rejected by Joana Martorini (joana.martorini@fgv.br), reason: Seu trabalho foi rejeitado devendo fazer alterações on 2016-06-14T20:01:27Z (GMT) / Submitted by Alexandra Cisotto Belline (alexandrabelline@yahoo.com.br) on 2016-06-15T19:08:39Z No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 14 06 2016.pdf: 8341218 bytes, checksum: 387a098a147e1b777b282c181b5bbe1c (MD5) / Rejected by Joana Martorini (joana.martorini@fgv.br), reason: Trabalho rejeitado. on 2016-06-15T19:24:58Z (GMT) / Submitted by Alexandra Cisotto Belline (alexandrabelline@yahoo.com.br) on 2016-06-15T21:22:31Z No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 15 06 2016.pdf: 8349846 bytes, checksum: 06c7baecfb96c1fde4d0888192b79639 (MD5) / Rejected by Renata de Souza Nascimento (renata.souza@fgv.br), reason: Trabalho rejeitado. Arrumar a numeração das páginas, conforme informado por telefone. Att. on 2016-06-15T21:51:14Z (GMT) / Submitted by Alexandra Cisotto Belline (alexandrabelline@yahoo.com.br) on 2016-06-15T22:46:58Z No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 15 06 2016 V2.pdf: 8347795 bytes, checksum: 78b9bb6d1a74cee3c4b50a58f24ea70e (MD5) / Approved for entry into archive by Renata de Souza Nascimento (renata.souza@fgv.br) on 2016-06-15T22:58:02Z (GMT) No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 15 06 2016 V2.pdf: 8347795 bytes, checksum: 78b9bb6d1a74cee3c4b50a58f24ea70e (MD5) / Made available in DSpace on 2016-06-16T12:16:07Z (GMT). No. of bitstreams: 1 Dissertação Alexandra Versão Entregue 15 06 2016 V2.pdf: 8347795 bytes, checksum: 78b9bb6d1a74cee3c4b50a58f24ea70e (MD5) Previous issue date: 2016-05-09 / Since the mid-1990s the Brazilian business environment has experienced a significant increase in the sophistication of modeling corporate structures for large enterprises, a type of knowledge, however, mostly restricted to participants in these ventures and its legal and financial counsel. In the case of the corporate structure of Brazil Telecom, however, it was possible to access all documents and information in order to study this structure, due to the massive litigation involving this company for almost ten years , where most part of the documents analyzed in this dissertation were found. This material is precious because the case of Brazil Telecom - known as one of the major in Brazilian corporate law - has a very important peculiarity: the group was managed by a minority shareholder, Opportunity group, which exercised power control during those ten years, despite its diminished equity interest and strong opposition suffered from major shareholders for most of the time in which that power was exercised. The aim of this study is to reveal the legal techniques that allowed the exercise of this power, as well as to seek to understand why, in spite of so much opposition from other shareholders and the massive litigation, it took years for the Opportunity to be definitely removed from the administration and the exercise of controlling power of Brazil Telecom. / Desde meados dos anos 1990 o ambiente de negócios brasileiro tem passado por um relevante incremento na sofisticação da modelagem de estruturas societárias para grandes empreendimentos, um tipo de conhecimento que, porém, fica na maior parte restrito aos participantes desses empreendimentos e seus assessores jurídicos e financeiros. No caso da estruturação societária da Brasil Telecom, entretanto, foi possível ter acesso a todos os documentos e informações necessários ao estudo dessa estrutura, devido à enorme quantidade de litígios judiciais em que essa companhia esteve envolvida por quase dez anos, nos quais se pode obter a maior parte dos documentos analisados neste trabalho. Esse material é precioso, pois o caso da Brasil Telecom, conhecido como um dos maiores do direito societário brasileiro, tem uma peculiaridade muito importante: o grupo era gerido por um acionista minoritário, o grupo Opportunity, que exerceu poder de controle durante esses dez anos, apesar de sua diminuta participação societária e da forte oposição que sofreu dos acionistas majoritários por quase todo o tempo em que exerceu esse poder. O objetivo desse trabalho é revelar as técnicas jurídicas que permitiram o exercício desse poder, bem como buscar entender por que, apesar de tanta oposição dos demais acionistas e da enorme litigiosidade, anos transcorreram até que o Opportunity fosse definitivamente afastado da administração e do exercício do poder de controle da Brasil Telecom.