CONSISTENT DYNAMICE CHOICE AND NON-EXPECTED UTILITY PREFERENCES

Pursuing works from Sarin and Wakker (1998), we study how NonExpected Utility models could be consistently applied to multi-stage decision problems. Concerning multiple priors model, we remove the argument that dynamic consistency, consequentialism and model consistency (sequential consistency in Sarin and Wakker (1998)) can all be preserved. Like Choquet expected utility, deviation of expected utility is only allowed over the final stage. Moreover, it's proved for the two models that if we also assume reduction of compound acts, then an expected utility representation exists in all stages.Choquet Expected Utility, Multiple Priors, Sequential Choice, Dynamic Consistency, Consequentialism, Reduction of Compound Acts.

Ichneumonid wasps from Madagascar. VI. The genus Pristomerus (Hymenoptera: Ichneumonidae: Cremastinae)

Pristomerus species of Madagascar are revised. We report 15 species, of which 12 are newly described: P. guinness sp. nov., P. hansoni sp. nov., P. kelikely sp. nov., P. keyka sp. nov., P. moramora sp. nov., P. melissa sp. nov., P. patator sp. nov., P. ranomafana sp. nov., P. roberti sp. nov., P. vahaza sp. nov., P. veloma sp. nov. and P. yago sp. nov. Pristomerus albescens (Morley) and P. cunctator Tosquinet are newly recorded from Madagascar and new host and/or distribution records are provided for this species. A dichotomous key to all species is provided. The zoogeographical relation of the Malagasy fauna of Pristomerus with respect to mainland Africa is discussed: only three of the 15 species are reported to occur outside of Madagascar, suggesting a high level of endemism in Madagascar which was not unexpected

Propriétés de transport pour l'étude de l'arc électrique. Exemple le cuivre.

Depuis la création d'un arc électrique entre deux électrodes de graphite à St Petersbourg par Petrov Vasili en 1803, la communauté scientifique n'a eu de cesse de modéliser, de mesurer toutes sortes de paramètres. Depuis le début du 20ième siècle, de nombreux appareillages industriels normalisés et certifiés existent et sont utilisés pour leur fiabilité, par exemple pour notre protection (fusibles, disjoncteurs,...). Depuis ces 2 siècles d'étude, nous pourrions penser que l'arc électrique est scientifiquement décrit de façon précise et satisfaisante. Malheureusement il n'en est rien. Les données de base de la description d'un arc électrique qui peuvent à la fois servir à l'interprétation des mesures, au dimensionnement de l'appareillage et à la modélisation sont les coefficients de transport : conductivité électrique, conductivité thermique et viscosité. Pour commenter l'évolution des connaissances dans ce domaine nous avons choisi le cuivre. Dans un premier paragraphe, nous discuterons les potentiels d'interaction choisis par plusieurs auteurs, puis nous donnerons les résultats des coefficients calculés par ces auteurs

Attitude toward information and learning under multiple priors

This paper studies learning under multiple priors by characterizing the decision maker's attitude toward information. She is incredulous if she integrates new information with respect to only those measures that minimizes the likelihood of the new information and credulous if she uses the maximum likelihood procedure to update her priors. Both updating rules expose her to dynamic inconsistency. We explore different ways to resolve this problem. One way consists to assume that the decision maker's attitude toward information is not relevant to characterize conditional preferences. In this case, we show that a necessary and sufficient condition, introduced by [Epstein L. and Schneider M., 2003. Recursive multiple priors. Journal of Economic Theory 113, 1-31], is the rectangularity of the set of priors. Another way is to extend optimism or pessimism to a dynamic set-up. A pessimistic (max-min expected utility) decision maker will be credulous when learning bad news but incredulous when learning good news.Conversely, an optimistic (max-max expected utility) decision maker will be credulous when learning good news but incredulous when learning bad news. It allows max-min (or max-max) expected utility preferences to be dynamically consistent but it violates consequentialism because conditioning works with respect to counterfactual outcomes. The implications of our findings when the set of priors is the core of a non-additive measure are explored.Multiple priors ; Learning ; Dynamic consistency ; Consequentialism ; Attitude toward information

X-ray reflectivity, diffraction and grazing incidence small angle X-ray scattering as complementary methods in the microstructural study of sol–gel zirconia thin films

X-ray reflectometry, X-ray diffraction and grazing incidence small angle X-ray scattering have been complementary used to fully characterize zirconia (ZrO2) thin films obtained by the sol–gel route. The films were synthesized on various sapphire (Al2O3), silicon (Si) and glass mirrorpolished wafers by a dip-coating process in a zirconia precursor sol. Versus the synthesis parameters as alkoxide sol concentration, withdrawal speed and annealing temperature, the microstructure of the layer is managed and its different microstructural parameters such as thickness, mass density, crystalline phase, grain size and spatial arrangement have been determined. The as prepared layers are amorphous. During a thermal treatment at low temperature (<1000 -C), the layers thickness decreases while their mass density increases. Simultaneously the zirconia precursor crystallises in the zirconia tetragonal form and the coating is made of randomly oriented nanocrystals which self organise in a dense close-packed microstructure. At low temperature, this microstructural evolution is similar whatever the substrate. Moreover, the layer evolves as the corresponding bulk xerogel showing that the presence of the interface does not modify the thermal microstructure evolution of the layer which is controlled by a normal grain growth leading to relatively dense nanocrystalline thin films

Updating Choquet Integrals , Consequentialism and Dynamic Consistency

Choquet capacities have been used to represent decision makers’ beliefs in order to generalise the expected utility approach. Conditional capacities have to be defined for dynamic choice situations where information may modify the decision maker future beliefs. Several updating rules have been proposed in the literature. We derive them from a general approach based on conditional Choquet expectations. Conversely, depending on the updating rule adopted, the conditional Choquet integral can take different values. Conditional Choquet Expected Utility are derived from axioms on preferences. However, it is now well-known in decision theory that if preferences satisfy simultaneously dynamic consistency and consequentialism axioms their representation is restricted to classical Expected Utility. We show that the rule proposed by Chateauneuf, Kast and Lapied (2001) is the only one to satisfy dynamic consistency with a nonnecessary additive capacityConditional Choquet expectation; Conditional capacity; Updating rules; Choquet Expected Utility; Dynamic consistency; Consequentialism.

Molecular Dynamics approach of sol–gel transition: Comparison with experiments

A new aggregation model by a Molecular Dynamics approach at constant temperature was compared with experimental results on a zirconia precursor gelling process. The evolution of the distribution of the experimental scattered intensities (small angle X-ray scattering curves), during gelling, was compared with the results of our Molecular Dynamics method, via the computation of structure factors of the numerical structure for different times:a very good agreement was found. Our numerical model allows one to understand the evolution as a function of time of the size and quantity of matter corresponding to the upper limit of the fractal domain