An ITK Implementation of the Symmetric Log-Domain Diffeomorphic Demons Algorithm

To be filled INThis article provides an implementation of the symmetric log-domain diffeomorphic image registration algorithm, or symmetric demons algorithm for short. It generalizes Thirion's demons and the diffeo- morphic demons algorithm. The main practical advantages of the symmetric demons with respect to the other demons variants is that is provides the inverse of the spatial transformation at no additional computational cost and ensures that the registration of image A to image B provides the inverse of the registration from image B to image A. The algorithm works completely in the log-domain, i.e. it uses a stationary velocity field to encode the spatial transformation as its exponential. Within the Insight Toolkit (ITK), the classical demons algorithm is implemented as part of the finite difference solver framework. Our code reuses and extends this generic framework. The source code is composed of a set of reusable ITK filters and classes together with their unit tests. We also provide a small example program that al- lows the user to compare the different variants of the demons algorithm. This paper gives an overview of the algorithm, an overview of its implementation and a small user guide to ease the use of the registration executable

ASTEX: a Hot path Based Thread Extractor for Distributed Memory System on a Chip

International audienceThis work addresses the early exploration phase, before the hardware is available, of the design of a System on a Chip. We detect threads in C programs using a software only technique. The computed threads are used as a basis for partitioning the applications. The threads are built using profiling and hot-paths information. We use a speculative model that, contrary to previous approaches, does not assume a shared memory. The speculation is performed on control flow and data structure layout. The output of the proposed method is a set of threads characterized by their execution time, the amount of memory and communication required, etc. Preliminary results show that the approach is able to capture and to characterize the main computation kernels of embedded applications

Rafaël Alberti et les avant-gardes

À l'occasion du centième anniversaire de la naissance de Rafael Alberti (1902-1999), le colloque, organisé en décembre 2002, par le CREC, et dont les PSN publient ici les actes, tenait à rendre hommage à l'une des principales personnalités des lettres espagnoles dont l'œuvre monumentale (en poésie, théâtre, prose, mais aussi peinture et dessin, ce que l'on connaît moins) couvre plus de trois quarts de siècle et se caractérise par une exceptionnelle vitalité et la quête permanente d'une esthétique à la fois rigoureuse et humaniste. Depuis le début des années 20 jusqu'à sa mort, pendant une période historique particulièrement longue et mouvementée (Dictature, République, Guerre d'Espagne, exil, restauration de la démocratie en Espagne), Alberti s'impose comme une figure de proue des avant-gardes esthétiques, puis des avant-gardes idéologiques et deviendra, après la guerre où il a joué un rôle de premier plan, une des voix majeures de l'exil républicain

On the relationship between valence and arousal in samples across the globe

Affect is involved in many psychological phenomena, but a descriptive structure, long sought, has been elusive. Valence and arousal are fundamental, and a key question–the focus of the present study–is the relationship between them. Valence is sometimes thought to be independent of arousal, but, in some studies (representing too few societies in the world) arousal was found to vary with valence. One common finding is that arousal is lowest at neutral valence and increases with both positive and negative valence: a symmetric V-shaped relationship. In the study reported here of self-reported affect during a remembered moment (N = 8,590), we tested the valence-arousal relationship in 33 societies with 25 different languages. The two most common hypotheses in the literature–independence and a symmetric V-shaped relationship–were not supported. With data of all samples pooled, arousal increased with positive but not negative valence. Valence accounted for between 5% (Finland) and 43% (China Beijing) of the variance in arousal. Although there is evidence for a structural relationship between the two, there is also a large amount of variability in this relation