Are beliefs a matter of taste? A case for Objective Imprecise Information

We argue, in the spirit of some of Jean-Yves Jaffray's work, that explicitly incorporating the information, however imprecise, available to the decision maker is relevant, feasible, and fruitful. In particular, we show that it can lead us to know whether the decision maker has wrong beliefs and whether it matters or not, that it makes it possible to better model and analyze how the decision maker takes into account new information, even when this information is not an event and finally that it is crucial when attempting to identify and measure the decision maker's attitude toward imprecise information.Decision under uncertainy;Objective Information;Belief Formation;Methodology of Decision Theory

Are Beliefs a Matter of Taste ? A case for Objective Imprecise Information

We argue, in the spirit of some of Jean-Yves Jaffray's work, that explicitly incorporating the information, however imprecise, available to the decision marker is relevant, feasible and fruitful. In particular, we show that it can lead us to know whether the decision maker has wrong beliefs and whether it matters or not, that it makes it possible to better model and analyze how the decision maker takes into account new information, even when this information is not an event and finally that it is crucial when attempting to identify and measure the decision maker's attitude toward imprecise information.Beliefs, imprecision, information.

Are Beliefs a Matter of Taste ? A case for Objective Imprecise Information

URL des Documents de travail : http://ces.univ-paris1.fr/cesdp/CESFramDP2009.htmDocuments de travail du Centre d'Economie de la Sorbonne 2009.86 - ISSN : 1955-611XWe argue, in the spirit of some of Jean-Yves Jaffray's work, that explicitly incorporating the information, however imprecise, available to the decision marker is relevant, feasible and fruitful. In particular, we show that it can lead us to know whether the decision maker has wrong beliefs and whether it matters or not, that it makes it possible to better model and analyze how the decision maker takes into account new information, even when this information is not an event and finally that it is crucial when attempting to identify and measure the decision maker's attitude toward imprecise information.Nous défendons l'idée qu'incorporer l'information disponible dans une approche axiomatique en théorie de la décision est pertinent, faisable et fructueux. Nous montrons que cela peut identifier les situations dans lesquelles le décideur a des croyances erronées, permet d'enrichir l'analyse d'arrivée de nouvelles informations et finalement est essentiel pour estimer l'attitude des décideurs face à l'imprécision

Global descent obstructions for varieties

We show how to transport descent obstructions from the category of covers to the category of varieties. We deduce examples of curves having \QQ as field of moduli, that admit models over every completion of \QQ, but have no model over \QQ

Load allocation problem for optimal design of aircraft electrical power system

More and more electric systems are embedded in today aircraft. As a result, the complexity of electrical power system design is increasing and the need of generic and efficient design methods is today required. Among numerous design tasks, the allocation of electric systems on the busbars of the electrical power system is considered as an important one since it has a direct impact on the aircraft mass. But due to the high number of possible allocations and regarding the large diversity of potential sizing cases for the equipments, finding the optimal allocation of electric loads is a hard task. In this paper, the problem is formalized mathematically. Then, four stochastic optimization methods are assessed on complex load allocation problems. Based on this assessment, a genetic algorithm using niching method is considered as the most appropriate algorithm for solving this aircraft design proble

Evolutionary conservation of P-selectin glycoprotein ligand-1 primary structure and function

<p>Abstract</p> <p>Background</p> <p>P-selectin glycoprotein ligand-1 (PSGL-1) plays a critical role in recruiting leukocytes in inflammatory lesions by mediating leukocyte rolling on selectins. Core-2 O-glycosylation of a <it>N</it>-terminal threonine and sulfation of at least one tyrosine residue of PSGL-1 are required for L- and P-selectin binding. Little information is available on the intra- and inter-species evolution of PSGL-1 primary structure. In addition, the evolutionary conservation of selectin binding site on PSGL-1 has not been previously examined in detail. Therefore, we performed multiple sequence alignment of PSGL-1 amino acid sequences of 14 mammals (human, chimpanzee, rhesus monkey, bovine, pig, rat, tree-shrew, bushbaby, mouse, bat, horse, cat, sheep and dog) and examined mammalian PSGL-1 interactions with human selectins.</p> <p>Results</p> <p>A signal peptide was predicted in each sequence and a propeptide cleavage site was found in 9/14 species. PSGL-1 <it>N</it>-terminus is poorly conserved. However, each species exhibits at least one tyrosine sulfation site and, except in horse and dog, a T [D/E]PP [D/E] motif associated to the core-2 <it>O</it>-glycosylation of a <it>N</it>-terminal threonine. A mucin-like domain of 250–280 amino acids long was disclosed in all studied species. It lies between the conserved <it>N</it>-terminal <it>O</it>-glycosylated threonine (Thr-57 in human) and the transmembrane domain, and contains a central region exhibiting a variable number of decameric repeats (DR). Interspecies and intraspecies polymorphisms were observed. Transmembrane and cytoplasmic domain sequences are well conserved. The moesin binding residues that serve as adaptor between PSGL-1 and Syk, and are involved in regulating PSGL-1-dependent rolling on P-selectin are perfectly conserved in all analyzed mammalian sequences. Despite a poor conservation of PSGL-1 <it>N</it>-terminal sequence, CHO cells co-expressing human glycosyltransferases and human, bovine, pig or rat PSGL-1 efficiently rolled on human L- or P-selectin. By contrast, pig or rat neutrophils were much less efficiently recruited than human or bovine neutrophils on human selectins. Horse PSGL-1, glycosylated by human or equine glycosyltransferases, did not interact with P-selectin. In all five species, tyrosine sulfation of PSGL-1 was required for selectin binding.</p> <p>Conclusion</p> <p>These observations show that PSGL-1 amino acid sequence of the transmembrane and cytoplasmic domains are well conserved and that, despite a poor conservation of PSGL-1 <it>N</it>-terminus, L- and P-selectin binding sites are evolutionary conserved. Functional assays reveal a critical role for post-translational modifications in regulating mammalian PSGL-1 interactions with selectins.</p

Equations of state implementation for 1-D modelling of performance in ram accelerator thermally choked propulsion mode

© 2015 Inderscience Enterprises Ltd. This paper presents advancement on one-dimensional (1-D) unsteady modelling of a ram accelerator (RAMAC) in the sub-detonative velocity regime by including real-gas equations of state (EoS) in order to account for the compressibility effects of the combustion products. Several equations of state based on generalised empirical and theoretical considerations are incorporated into a 1-D computer code TARAM. The objective of this work is to provide the best available formulations in order to improve the unsteady 1-D model and make the TARAM code a useful tool to predict the performance of the RAMAC in the sub-detonative velocity regime, without having to resort to more complicated 2-D or 3-D computational schemes. The calculations are validated against experimental data from 38-mm and 90-mm-bore facilities and good agreements have been achieved. Yet, the results demonstrate the need for further CFD studies involving the scale effect

Méthodes et outils pour la conception optimale des réseaux de distribution d'électricité dans les aéronefs

Dans le domaine aéronautique, la dernière décennie a été marquée par une augmentation constante et progressive du taux d électrification des systèmes embarqués. L avion plus électrique est aujourd hui vu comme un axe d amélioration majeure pour l industrie aéronautique permettant d atteindre des objectifs toujours plus ambitieux : réduction de l impact environnemental, rationalisation des coûts de maintenance Dans ce contexte, le réseau de distribution électrique joue un rôle majeur. Les architectes doivent imaginer de nouveaux concepts architecturaux afin d assurer le service de fourniture d électricité tout en minimisant la masse et le coût. Ainsi les travaux de cette thèse proposent des méthodes d aide à la conception pour les architectes de réseau. Le manuscrit se divise en 2 parties pouvant être vues comme 2 études distinctes et qui sont introduites dans le chapitre 1.La 1ère partie, traitée dans les chapitres 2 et 3, développe des méthodes et outils afin de résoudre de manière automatique et optimale 2 tâches de l architecte : la définition des reconfigurations du réseau et l identification de l allocation des charges. La formalisation de ces 2 problématiques met en lumière une caractéristique commune : l explosion combinatoire. Ainsi les résolutions sont réalisées à l aide de méthodes issues de la recherche opérationnelle. Un processus général est défini afin de traiter les 2 tâches de manière consistante. Les aspects liés à la reconfiguration sont traités à l aide de : la théorie des graphes pour modéliser la connectivité du réseau, un système expert capturant les règles métiers et la programmation linéaire sélectionnant les reconfigurations les plus performantes. La méthode a été appliquée avec succès sur des réseaux avions existants (A400M et A350) ainsi que sur des réseaux plus électriques prospectifs. La deuxième tâche consistant en l allocation des charges a été résolue à l aide de méthodes stochastiques. L algorithme génétique utilisant une méthode de nichage se révèle être le plus performant en proposant à l architecte réseau des solutions performantes et variées. La 2ème partie, traitée dans le chapitre 4, s intéresse à un nouveau concept le cœur électronique modulaire et mutualisé . Cet organe de distribution, étroitement lié à l avion plus électrique, se caractérise par la mutualisation de m modules électronique de puissance pour c charges électriques. Les méthodes développées dans le chapitre 4 vise à concevoir de manière optimale ce nouveau cœur en ayant 2 degrés de liberté : le nombre m de modules et les reconfigurations entre les m modules et les c charges. De nouveau, la formalisation du problème met en évidence l explosion combinatoire à laquelle est confronté le concepteur. Le principal objectif de cette étude est de proposer un cadre méthodologique pour la résolution de ce problème de conception. Ainsi une heuristique a été développée pour résoudre ce problème combinatoire. Une attention particulière a été portée pour développer des modèles de composants simples et génériques dans une procédure générale organisée. Enfin une cartographie a été réalisée afin de dégager d une part les formes de solutions les plus performantes et d identifier les éléments ayant les impacts les plus significatifs sur la masse du système complet.In the aeronautics field, the last decade has been marked by a constant and gradual increase of the electrification rate of the embedded systems. Today, the More Electric Aircraft (MEA) is seen as a major axis of improvement for the aviation industry to achieve increasingly ambitious objectives: reducing environmental impact, rationalisation of maintenance costs...In the more electrical aircraft concept, the electrical network plays a major role. Today engineers must imagine new architectural solutions to ensure the electricity supply while minimizing weight and cost. In this context, the PhD work consists in providing new methods to support the design of electrical network architectures. The PhD work is divided into 2 parts which can be seen as 2 separate studies which are introduced in the chapter 1.The 1st part, treated in the chapters 2 and 3, develops methods and tools to solve problems automatically for 2 architecture tasks: the definition of the network reconfiguration and the identification of the electrical load allocation on busbars. The formalization of these two issues highlights a common characteristic: the combinatorial explosion. As the consequence, methods from operational research area are selected to solve the 2 tasks in the frame of a general and consistent design process. The reconfiguration aspects are solved by a methodology coupling together: graph theory to model the network connectivity, an expert system capturing know-how rules and linear programming selecting the most efficient reconfiguration. The approach was successfully applied on existing aircraft electrical networks (A400M and A350) and on future architectures. The second task, related to the electrical load allocation, is solved using stochastic methods. The genetic algorithm using a niching method is the best assessed optimization method. It provides good and diversified load allocations to the electrical network architect. The 2nd part, treated in the chapter 4, focuses on a new technological concept the modular and mutualised power electronics center . This distribution system, closely linked to the more electrical aircraft, aims at sharing m power electronics modules to c electrical loads. The methods developed in this PhD aim at carrying out an optimal design of this new power center with 2 design variables: the number m of modules and the reconfigurations between the m modules and the c loads. Again, the formalization of the problem highlights that the designer must deal with a combinatorial explosion. The main objective of this study is to propose a methodological framework for solving this design problem. A heuristic-based algorithm is developed to solve this combinatorial optimization problem. A particular attention is paid to develop an organized weight estimation procedure using generic sizing models. Finally a mapping is performed to identify the best solutions and to highlight the technological elements having the most significant impact on the complete system weightTOULOUSE-INSA-Bib. electronique (315559905) / SudocSudocFranceF

Aprendizaje cooperativo: una nueva metodología motivadora para el alumno

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