Systemic Risk and Network Formation in the Interbank Market

We propose a novel mechanism to facilitate understanding of systemic risk in financial markets. The literature on systemic risk has focused on two mechanisms, common shocks and domino-like sequential default. Our approach is a formal model that provides an intellectual combination of the two by looking at how shocks propagate through a network of interconnected banks. Transmission in our model is not based on default. Instead, we provide a simple microfoundation of banks’ profitability based on classic competition incentives. As competitors lending quantities change, both for closely connected ones and the whole market, banks adjust their own lending decisions as a result, generating a ‘transmission’ of shocks through the system. We provide a unique equilibrium characterization of a static model, and embed this model into a full dynamic model of network formation with n agents. Because we have an explicit characterization of equilibrium behavior, we have a tractable way to bring the model to the data. Indeed, our measures of systemic risk capture the propagation of shocks in a wide variety of contexts; that is, it can explain the pattern of behavior both in good times as well as in crisis.Financial networks; interbank lending; interconnections; network centrality; spatial autoregressive models

Decision under Uncertainty : the Classical Models

This chapiter of a collective book is dedicated to classical decision models under uncertainty, i.e. under situations where events do not have "objective" probabilities with which the Decision Marker agrees. We present successively the two main theories, their axiomatic, the interpretation and the justification of their axioms and their main properties : first, the general model of Subjective Expected Utility due to Savage (Savage, 1954), second, the Anscombe-Aumann (1963) theory, in a different framework. Both theories enforce the universal use of a probabilistic representation. We then discuss this issue in connection with the experimental result known as the Ellsberg paradox.Uncertainty, subjective probability, Subjective Expected Utility, Savage, Anscombe and Aumann, Ellsberg paradox.

Multigrain Affinity for Heterogeneous Work Stealing

International audienceIn a parallel computing context, peak performance is hard to reach with irregular applications such as sparse linear algebra operations. It requires dynamic adjustments to automatically balance the workload between several processors. The problem becomes even more complicated when an architecture contains processing units with radically different computing capabilities. We present a hierarchical scheduling scheme designed to harness several CPUs and a GPU. It is built on a two-level work stealing mechanism tightly coupled to a software-managed cache. We show that our approach is well suited to dynamically control heterogeneous architectures, while taking advantage of a reduction of data transfers

Two dimensional Leidenfrost Droplets in a Hele Shaw Cell

We experimentally and theoretically investigate the behavior of Leidenfrost droplets inserted in a Hele-Shaw cell. As a result of the confinement from the two surfaces, the droplet has the shape of a flattened disc and is thermally isolated from the surface by the two evaporating vapor layers. An analysis of the evaporation rate using simple scaling arguments is in agreement with the experimental results. Using the lubrication approximation we numerically determine the shape of the droplets as a function of its radius. We furthermore find that the droplet width tends to zero at its center when the radius reaches a critical value. This prediction is corroborated experimentally by the direct observation of the sudden transition from a flattened disc into an expending torus. Below this critical size, the droplets are also displaying capillary azimuthal oscillating modes reminiscent of a hydrodynamic instability

Tamara Kondratieva, éd., Les Soviétiques

Ce livre est important. En quatorze chapitres rédigés par des historiens confirmés presque tous originaires de l’ex-URSS, il propose une image nouvelle de l’histoire de l’Union soviétique et de la vie de ses citoyens. L’angle d’approche porte sur les « régimes », terme un peu difficile à appréhender pour des francophones : il ne s’agit pas du régime politique, mais de différents ensembles de règles qui régissent l’activité et le comportement des personnes ou des choses dans des domaines spéci..

Les localités circulatoires

Que faire des propos de nos vigoureux prédécesseurs ? Les mots ne sont pas mâchés. Voici ce que Fernand Braudel relève chez Marc Bloch : « Il n’y a pas d’histoire de France, il y a une histoire de l’Europe » ; à quoi Braudel ajoute dans la foulée ce second propos de Bloch qui lui semble non pas seulement compléter le premier, mais lui donner son sens : « La seule histoire véritable est l’histoire universelle ». Et Braudel de ponctuer : « Il n’y a pas d’histoire de l’Europe, il y a une histoir..

O século de Taylor, Lênin e Freud

This article examines the notion of practice over the course of the twentieth century. It shows that three systems of regulating practices - namely Taylorism, Leninism and psychoanalysis - launched their programs in 1900, each within its own specific domain but sharing the same organized relationship between scientific claims and action (of the workers in the first case, the masses in the second and the patient under analysis in the third, all under the direction of professionals). For decades, each of these systems had its place of inscription and migration, along with the people who embodied them. They formalized the valuation frameworks comprised by efficiency, political struggle and psycho-affective equilibrium. The article provides an in-depth analysis of the Taylorist conception of the norms of other people's practice by identifying the diverse variables of the latter (object, reference, temporality, space, serialization, materiality, employees, etc.). It concludes by providing a sketch of twentieth century history as a circulation of practices from a framework of valorizing the other (existence, a nomination, calculation, efficiency, politics, affect, ethics, aesthetics) and, consequently, from one region of the world to another in pursuit of its primordial inscriptions.Este artigo percorre o século xx do ponto de vista da prática. Ele mostra que três regimes de regulação das práticas, quais sejam, o taylorismo, o leninismo e a psicanálise, lançaram seus programas em 1900, cada um em seu domínio, porém partilhando a mesma relação organizada entre a pretensão científica e a ação (dos operários para o primeiro, das massas para o segundo e do paciente em sessão para o terceiro, todos sob a direção de profissionais). Cada um desses regimes teve, durante décadas, seu lugar de inscrição e de peregrinação, bem como os portadores que os encarnavam. Eles formalizaram os quadros de valorização que são a eficácia, a luta política e o equilíbrio psicoafetivo. O artigo trata de modo aprofundado da prática taylorista de concepção das normas da prática dos outros ao identificar as diversas variáveis desta (o objeto, a referência, a temporalidade, o espaço, a serialização, a materialidade, os funcionários etc.). Conclui esboçando um cenário da história do século xx como circulação de práticas de um quadro de valorização a outro (a existência, a nominação, o cálculo, a eficácia, a política, o afetivo, a ética, a estética) e, desse modo, de uma região do mundo a outra a fim de seguir suas inscrições primordiais