Premium Risk net of Reinsurance: from short-term to medium term assessment

Solvency II requirements introduced new issues for actuarial risk management in non-life insurance, challenging the market to have a consciousness of its own risk profile, and also investigating the sensitivity of the solvency ratio depending on the insurance risks and technical results on either a short-term and medium-term perspective. For this aim, in the present paper, a partial internal model for premium risk is developed for three multi-line non-life insurers, and the impact of some different business mixes is analyzed. Furthermore, the risk-mitigation and profitability impact of reinsurance in the premium risk model are introduced, and a global framework for a feasible application of this model consistent with a medium-term analysis is provided. Numerical results are also figured out with evidence of various effects for several portfolios and reinsurance arrangements, pointing out the main reasons for these differences

T-branes through 3d mirror symmetry

T-branes are exotic bound states of D-branes, characterized by mutually non-commuting vacuum expectation values for the worldvolume scalars. The M/F-theory geometry lifting D6/D7-brane configurations is blind to the T-brane data. In this paper, we make this data manifest, by probing the geometry with an M2-brane. We find that the effect of a T-brane is to deform the membrane worldvolume superpotential with monopole operators, which partially break the three-dimensional flavor symmetry, and reduce supersymmetry from N=4 to N=2. Our main tool is 3d mirror symmetry. Through this language, a very concrete framework is developed for understanding T-branes in M-theory. This leads us to uncover a new class of N=2 quiver gauge theories, whose Higgs branches mimic those of membranes at ADE singularities, but whose Coulomb branches differ from their N=4 counterparts.Comment: 36 page

F-theory on singular spaces

We propose a framework for treating F-theory directly, without resolving or deforming its singularities. This allows us to explore new sectors of gauge theories, including exotic bound states such as T-branes, in a global context. We use the mathematical framework known as Eisenbud's matrix factorizations for hypersurface singularities. We display the usefulness of this technique by way of examples, including affine singularities of both conifold and orbifold type, as well as a class of full-fledged compact elliptically fibered Calabi-Yau fourfolds.Comment: 35 pages, 4 figures, minor revision

Kiakhta ou l'épaisseur de la frontière

International audienceThis article is a reflection on the question of what is a “frontier.” The history of the three Kiakhtas (this name also designates Troitskosavsk and the Chinese trading town of Maimaicheng) reveals throughout the XVIIIth and XIXth centuries some particularly exceptional features. These were due to the unique position of the city on the border between the Russian and Chinese Empires. As a result of important trading and smuggling activities, which gave rise to a pidgin language between Russian and Chinese merchants and to the vanishing of social barriers, this frontier, which gathers together people and civilizations rather than separates them, became a lively battering hub. A window onto the world, the “Millionnaires’ town,” known as “The Venice of the Desert,” was also an exchange post for revolutionary ideas, an outpost for Orientalism and the cultural centre of Transbaikalia. Engaging with Kiakhta – which is considered here from the point of view of Western culture (including Russia) – is an opportunity to broach various debates: the fashion of chinoiserie in Russia as well as asiatism in that country; the status of Siberia given its proximity to China; and the historiography of Russian-Chinese relations.Cet article s’ordonne autour d’une réflexion sur la frontière. L’histoire de la triple ville de Kiakhta (celle-ci désignant également Troitskosavsk et Maimaicheng, la ville marchande chinoise) révèle, tout au long des xviiie et xixe siècles, des particularités assez exceptionnelles qui tiennent à sa position aux limites des Empires russe et chinois. La frontière, en ce lieu, a réuni plus qu’elle n’a séparé ; elle s’est animée grâce à un commerce fondé sur le troc et à un trafic d’envergure ; elle a engendré un pidgin à usage des marchands russes et chinois et, phénomène plus singulier, elle a entraîné dans le même temps un décloisonnement social marqué. Fenêtre sur le monde, la « ville des millionnaires », dénommée aussi la « Venise des sables », a été à la fois un lieu de passage des idées révolutionnaires, un avant-poste de l’orientalisme et le centre culturel de la Transbaïkalie. L’évocation de Kiakhta, abordée ici dans une optique occidentale (russe incluse), est l’occasion d’effleurer des débats concernant la mode des chinoiseries en Russie, l’asiatisme russe, le statut de la Sibérie entre Chine et Russie occidentale ainsi que l’historiographie des relations russo-chinoises

A Community Microgrid Architecture with an Internal Local Market

This work fits in the context of community microgrids, where members of a community can exchange energy and services among themselves, without going through the usual channels of the public electricity grid. We introduce and analyze a framework to operate a community microgrid, and to share the resulting revenues and costs among its members. A market-oriented pricing of energy exchanges within the community is obtained by implementing an internal local market based on the marginal pricing scheme. The market aims at maximizing the social welfare of the community, thanks to the more efficient allocation of resources, the reduction of the peak power to be paid, and the increased amount of reserve, achieved at an aggregate level. A community microgrid operator, acting as a benevolent planner, redistributes revenues and costs among the members, in such a way that the solution achieved by each member within the community is not worse than the solution it would achieve by acting individually. In this way, each member is incentivized to participate in the community on a voluntary basis. The overall framework is formulated in the form of a bilevel model, where the lower level problem clears the market, while the upper level problem plays the role of the community microgrid operator. Numerical results obtained on a real test case implemented in Belgium show around 54% cost savings on a yearly scale for the community, as compared to the case when its members act individually.Comment: 16 pages, 15 figure

Energy Conversion Using New Thermoelectric Generator

During recent years, microelectronics helped to develop complex and varied technologies. It appears that many of these technologies can be applied successfully to realize Seebeck micro generators: photolithography and deposition methods allow to elaborate thin thermoelectric structures at the micro-scale level. Our goal is to scavenge energy by developing a miniature power source for operating electronic components. First Bi and Sb micro-devices on silicon glass substrate have been manufactured with an area of 1cm2 including more than one hundred junctions. Each step of process fabrication has been optimized: photolithography, deposition process, anneals conditions and metallic connections. Different device structures have been realized with different micro-line dimensions. Each devices performance will be reviewed and discussed in function of their design structure.Comment: Submitted on behalf of TIMA Editions (http://irevues.inist.fr/tima-editions

F-theory at order α′3\alpha'^3

We study the effective physics of F-theory at order $\alpha'^3$ in derivative expansion. We show that the ten-dimensional type IIB eight-derivative couplings involving the graviton and the axio-dilaton naturally descend from pure gravity in twelve dimensions. Upon compactification on elliptically fibered Calabi-Yau fourfolds, the non-trivial vacuum profile for the axio-dilaton leads to a new, genuinely N=1, $\alpha'^3$ correction to the four-dimensional effective action.Comment: 24 pages, minor improvements, typos correcte

L'oral enfantin. Quelques précautions pour l'évaluer

National audienceA description established on the basis of oral children corpus, enables us to make three types of comments. The majority of the oral phenomena are present in the oral adult corpora. A small number of facts seem specific to the children and are to be put in relation to their age. They relate to the morphophonology, the lexical items and the morphosyntax. Considering the syntax, nothing makes it possible to point out a childish linguistic specificity. If the children statements are not compared with written statements but well with adult oral statements, it appears that the children have acquired the syntax of their language.Un inventaire établi à partir de corpus d'enfants, nous permet de faire trois types de remarques. Les phénomènes observés sont, pour la plupart, représentés dans les corpus d'adultes. Un petit nombre de faits semblent spécifiques aux enfants et sont à mettre en relation avec leur âge. Ils portent sur la morphophonologie, le lexique et la morphosyntaxe. Dans le domaine de la syntaxe, rien ne permet de pointer une spécificité langagière enfantine. Si on prend la précaution de ne pas confronter les énoncés d'enfants à des énoncés écrits mais bien à des énoncés oraux, il apparaît que les enfants sont ancrés dans la langue