Un bestiario futuro: exorcismos proyectivos en la ciencia ficción

Conferencias y Comunicaciones del primer Congreso Internacional de literatura fantástica y ciencia ficción, celebrado del 6 al 9 de mayo de 2008 en la Universidad Carlos III de Madri

Las redes sociales pueden paliar la soledad

Siete años después de quedar finalista del Nadal, el premio más longevo de las letras españolas, Carmen Amoraga se alzó con este galardón gracias a su novela ´La vida era eso’. La obra narra la historia de superación de una mujer que, tras enviudar, encuentra en las redes sociales –algo que apenas conocía una forma de superar el duelo y recuperar su propia vida.Contiene: Las redes sociales pueden paliar la soledad / Carmen Amoraga (pp.16-19) .-- Historia de un premio / David Conte Imbert (p. 17) .-- Tan parecidos.Tan distintos / Juan Pedro Molina Cañabate (p. 19)

Towards a Mini-App for Smoothed Particle Hydrodynamics at Exascale

The smoothed particle hydrodynamics (SPH) technique is a purely Lagrangian method, used in numerical simulations of fluids in astrophysics and computational fluid dynamics, among many other fields. SPH simulations with detailed physics represent computationally-demanding calculations. The parallelization of SPH codes is not trivial due to the absence of a structured grid. Additionally, the performance of the SPH codes can be, in general, adversely impacted by several factors, such as multiple time-stepping, long-range interactions, and/or boundary conditions. This work presents insights into the current performance and functionalities of three SPH codes: SPHYNX, ChaNGa, and SPH-flow. These codes are the starting point of an interdisciplinary co-design project, SPH-EXA, for the development of an Exascale-ready SPH mini-app. To gain such insights, a rotating square patch test was implemented as a common test simulation for the three SPH codes and analyzed on two modern HPC systems. Furthermore, to stress the differences with the codes stemming from the astrophysics community (SPHYNX and ChaNGa), an additional test case, the Evrard collapse, has also been carried out. This work extrapolates the common basic SPH features in the three codes for the purpose of consolidating them into a pure-SPH, Exascale-ready, optimized, mini-app. Moreover, the outcome of this serves as direct feedback to the parent codes, to improve their performance and overall scalability.Comment: 18 pages, 4 figures, 5 tables, 2018 IEEE International Conference on Cluster Computing proceedings for WRAp1

The Obscure Cities, by Schuiten and Peeters: a Topography of Dislocation

Las Ciudades oscuras, ciclo de novelas gráficas emprendido en 1982 por el dibujante belga François Schuiten y el guionista francés Benoît Peeters, constituyen un caso paradigmático de confluencia entre lo urbano y la ciencia ficción. Este mundo imaginario, que se enmarca dentro de la esfera del steampunk, reconfigura en sus ciudades un mosaico de los diferentes estilos arquitectónicos de nuestra civilización, rescatando a la vez su dimensión visionaria y utópica. El presente trabajo se propone esbozar un recorrido por sus principales claves estéticas y narrativas. Más que un"espejo de nuestro presente", lo que plantea el ciclo de las Ciudades oscuras es una evocación del ideal positivista y funcional que impregna el imaginario urbanístico contemporáneo. La irrupción de lo fantástico en esta perspectiva racionalista trastoca las posibilidades de armonía y equilibrio,para arrastrar a sus habitantes a una desubicación donde se proyecta la condición errante del sujeto actual.The Obscure Cities graphic novels cycle, started in 1982 by the Belgian draftsman François Schuiten and the comic’s writer Benoît Peeters, is a prime example of convergence between urban and science fiction. This imaginary world, which falls within the realm of steampunk, reconfigures in their cities a mosaic of different architectural styles of our civilization, rescuing both visionary and utopian dimension. This entry aims to outline a tour of its aesthetic and narrative main keys. More than a “mirror of our present”, what the Obscure Cities cycle arises is an evocation of the positivist and functional ideal that pervades the contemporary urban imaginary. The inrush of the fantastic in this rationalist perspective disrupts the possibilities of harmony and balance, to drag its inhabitants to a dislocation where the wandering condition of the contemporary subject is projected

SPH-EXA: Enhancing the Scalability of SPH codes Via an Exascale-Ready SPH Mini-App

Numerical simulations of fluids in astrophysics and computational fluid dynamics (CFD) are among the most computationally-demanding calculations, in terms of sustained floating-point operations per second, or FLOP/s. It is expected that these numerical simulations will significantly benefit from the future Exascale computing infrastructures, that will perform 10^18 FLOP/s. The performance of the SPH codes is, in general, adversely impacted by several factors, such as multiple time-stepping, long-range interactions, and/or boundary conditions. In this work an extensive study of three SPH implementations SPHYNX, ChaNGa, and XXX is performed, to gain insights and to expose any limitations and characteristics of the codes. These codes are the starting point of an interdisciplinary co-design project, SPH-EXA, for the development of an Exascale-ready SPH mini-app. We implemented a rotating square patch as a joint test simulation for the three SPH codes and analyzed their performance on a modern HPC system, Piz Daint. The performance profiling and scalability analysis conducted on the three parent codes allowed to expose their performance issues, such as load imbalance, both in MPI and OpenMP. Two-level load balancing has been successfully applied to SPHYNX to overcome its load imbalance. The performance analysis shapes and drives the design of the SPH-EXA mini-app towards the use of efficient parallelization methods, fault-tolerance mechanisms, and load balancing approaches.Comment: arXiv admin note: substantial text overlap with arXiv:1809.0801

Are larger studies always better? Sample size and data pooling effects in research communities

The persistent pervasiveness of inappropriately small studies in empirical fields is regu-larly deplored in scientific discussions. Consensually, taken individually, higher-powered studies are more likely to be truth-conducive. However, are they also beneficial for the wider performance of truth-seeking communities? We study the impact of sample sizes on collective exploration dynamics under ordinary conditions of resource limita-tion. We find that large collaborative studies, because they decrease diversity, can have detrimental effects in certain realistic circumstances that we characterize precisely. We show how limited inertia mechanisms may partially solve this pooling dilemma and dis-cuss our findings briefly in terms of editorial policies

La ciudad: imágenes e imaginarios

Libro de actas del Congreso Internacional Interdisciplinar "La ciudad: imágenes e imaginarios" celebrado en la Facultad de Humanidades, Comunicación y Documentación, Universidad Carlos III de Madrid del 12 al 15 marzo de 2018

Éditorial

Ce onzième numéro de la revue e-migrinter est issu des journées d’étude organisées par l’Unité Mixte de Recherche (UMR) Migrinter et l’axe « Mobilités, Identités, Territoires » du Collège International des Sciences du Territoire (CIST), qui se sont tenues à la Maison des Sciences de l’Homme et de la Société de Poitiers les 19 et 20 novembre 2012. Les contributions réunies dans ce dossier interrogent les rapports entre mobilité et immobilité, dans des champs thématiques et des terrains variés,..

Synthèse des débats

Au fil de ces deux journées, deux réflexions transversales ont plus spécifiquement accompagné les échanges et nourri les débats autour des réflexions développées dans des contextes variés par chacun des intervenants. La première concerne le caractère subi/choisi de la circulation, le degré de contrainte plus ou moins fort qui pèse sur les pratiques sociales et spatiales, qui est loin de concerner uniquement la session dédiée à l’immobilité forcée. La seconde renvoie à la question des échelles..

Improving Goldschmidt Division, Square Root and Square Root Reciprocal

The aim of this paper is to accelerate division, square root and square root reciprocal computations, when Goldschmidt method is used on a pipelined multiplier. This is done by replacing the last iteration by the addition of a correcting term that can be looked up during the early iterations. We describe several variants of the Goldschmidt algorithm assuming 4-cycle pipelined multiplier and discuss obtained number of cycles and error achieved. Extensions to other than 4-cycle multipliers are given.Le but de cet article est l'accélération de la division, et du calcul de racines carrées et d'inverses de racines carrées lorsque la méthode de Goldschmidt est utilisée sur un multiplieur pipe-line. Nous faisons ceci en remplaçant la dernière itération par l'addition d'un terme de correction qui peut être déduit d'une lecture de table effectuée lors des premières itérations. Nous décrivons plusieurs variantes de l'algorithme obtenu en supposant un multiplieur à 4 étages de pipe-line, et donnons pour chaque variante l'erreur obtenue et le nombre de cycles de calcul. Des extensions de ce travail à des multiplieurs dont le nombre d'étages est différent sont présentées