Towards functional safety in automotive electronics

International audienceThe part of electronics in automobile design becomes more and more important with an exponential growth during the last 10 years. Nowadays, innovation in automotive industry is driven by electronics. New upcoming electrical/electronic systems (E/E systems) such as advanced driver assistance systems or x-by-wire systems as well as consumer expectation regarding safety will require a dedicated standard to ensure design, development and production of safe products before their introduction on the market.ISO/TC22/SC3/WG16 has been formed to issue the ISO26262 international standard that will specifically address functional safety of E/E systems of automotive industry.This paper provides information about the future ISO26262 which is based on the current results of ISO/TC22/SC3/WG16 [1], those still being subject to changes before the international standard release

Symmetry and Electronic Structure of Noble Metal Nanoparticles and the Role of Relativity

High resolution photoelectron spectra of cold mass selected Cu_n-, Ag_n- and Au_n- with n =53-58 have been measured at a photon energy of 6.42 eV. The observed electron density of states is not the expected simple electron shell structure, but seems to be strongly influenced by electron-lattice interactions. Only Cu55- and Ag55- exhibit highly degenerate states. This is a direct consequence of their icosahedral symmetry, as is confirmed by density functional theory calculations. Neighboring sizes exhibit perturbed electronic structures, as they are formed by removal or addition of atoms to the icosahedron and therefore have lower symmetries. Gold clusters in the same size range show completely different spectra with almost no degeneracy, which indicates that they have structures of much lower symmetry. This behaviour is related to strong relativistic bonding effects in gold, as demonstrated by ab initio calculations for Au55-.Comment: 10 pages, 3 figure

Two-dimensional solitons on the surface of magnetic fluids

We report an observation of a stable soliton-like structure on the surface of a ferrofluid, generated by a local perturbation in the hysteretic regime of the Rosensweig instability. Unlike other pattern-forming systems with localized 2D structures, magnetic fluids are characterized by energy conservation; hence their mechanism of soliton stabilization is different from the previously discussed gain/loss balance mechanism. The radioscopic measurements of the soliton's surface profile suggest that locking on the underlying periodic structure is instrumental in its stabilization.Comment: accepted for publication by Physical Review Letter

Removing data and using metafounders alleviates biases for all traits in Lacaune dairy sheep predictions

Bias in dairy genetic evaluations, when it exists, has to be understood and properly addressed. The origin of biases is not always clear. We analyzed 40 yr of records from the Lacaune dairy sheep breeding program to evaluate the extent of bias, assess possible corrections, and emit hypotheses on its origin. The data set included 7 traits (milk yield, fat and protein contents, somatic cell score, teat angle, udder cleft, and udder depth) with records from 600,000 to 5 million depending on the trait,-1,900,000 animals, and-5,900 genotyped elite artificial insemination rams. For the-8% animals with missing sire, we fit 25 unknown parent groups. We used the linear regression method to compare "partial" and "whole" predictions of young rams before and after progeny testing, with 7 cut-off points, and we obtained estimates of their bias, (over)dispersion, and accuracy in early proofs. We tried (1) several scenarios as follows: multiple or single trait, the "official" (routine) evalua-tion, which is a mixture of both single and multiple trait, and "deletion" of data before 1990; and (2) sev-eral models as follows: BLUP and single-step genomic (SSG)BLUP with fixed unknown parent groups or metafounders, where, for metafounders, their relation-ship matrix gamma was estimated using either a model for inbreeding trend, or base allele frequencies esti-mated by peeling. The estimate of gamma obtained by modeling the inbreeding trend resulted in an estimated increase of inbreeding, based on markers, faster than the pedigree-based one. The estimated genetic trends were similar for most models and scenarios across all traits, but were shrunken when gamma was estimated by peeling. This was due to shrinking of the estimates of metafounders in the latter case. Across scenarios, all traits showed bias, generally as an overestimate of genetic trend for milk yield and an underestimate for the other traits. As for the slope, it showed overdisper-sion of estimated breeding values for all traits. Using multiple-trait models slightly reduced the overestimate of genetic trend and the overdispersion, as did including genomic information (i.e., SSGBLUP) when the gam-ma matrix was estimated by the model for inbreeding trend. However, only deletion of historical data before 1990 resulted in elimination of both kind of biases. The SSGBLUP resulted in more accurate early proofs than BLUP for all traits. We considered that a snowball ef-fect of small errors in each genetic evaluation, combined with selection, may have resulted in biased evaluations. Improving statistical methods reduced some bias but not all, and a simple solution for this data set was to remove historical records

Redox-active ferrocene-modified Cowpea mosaic virus nanoparticles

A naturally occurring nanoparticle, the plant virus Cowpea mosaic virus, can be decorated with ferrocene derivatives, of various linker lengths with amine and carboxylategroups, on the external surface using a range of conjugation strategies. The multiple, organometallic, redox-active ferrocene moieties on the outer surface of the virus are electrochemically independent with reduction potentials that span a potential window of 0.16 V that are dependent on the site of modification and the nature of the ferrocene derivative. The number of ferrocenes coupled to each virus ranges from about 100 to 240 depending upon the conjugation site and the linker length and these redox active units can provide multielectron reservoirs

Etude des fonctions B-splines non-uniformes pour la reconstruction d'un signal discret à partir d'un échantillonnage irrégulier

Cet article traite le problème de la reconstruction d'un signal discret à partir de ses échantillons prélevés à des instants irréguliers. La méthode proposée est une méthode de reconstruction locale basée sur des fonctions B-splines non-uniformes. Sous certaines contraintes (multiplicité imposée aux noeuds, support minimal), nous généralisons la construction des éléments de la base de la fonction spline. Quel que soit le degré de la fonction spline, nous montrons que deux noeuds sont suffisants pour une reconstruction locale du signal. Nous généralisons le calcul des coefficients de la fonction spline. Une extension de la méthode à un signal bidimensionnel est proposée. Les résultats des simulations sont satisfaisants

Interpolation statistique à partir d'un échantillonnage irrégulier pour la reconstruction d'images

Dans cet article, nous proposons une méthode irréversible de compression de données, fondée sur le principe de sous-échantillonnage d'une grille d'image. Nous nous intéressons particulièrement aux problèmes de la reconstruction numérique d'images à partir de données dispersées irrégulièrement sous la contrainte de perte minimale d'information. L'estimation d'un pixel, localisé à un emplacement connu sur la grille d'image, est déterminée par une méthode basée sur les corrélations spatiales entre les pixels de l'image. Dans un premier temps, nous déterminons expérimentalement les corrélations spatiales entre les pixels de l'image. Celles ci sont ensuite approximées par un modèle théorique de corrélation. Le processus de sous-échantillonnage irrégulier de l'image est réalisé par un algorithme d'optimisation des positions des pixels dans le but de réduire l'erreur quadratique moyenne due à la reconstruction

Two and three-dimensional oscillons in nonlinear Faraday resonance

We study 2D and 3D localised oscillating patterns in a simple model system exhibiting nonlinear Faraday resonance. The corresponding amplitude equation is shown to have exact soliton solutions which are found to be always unstable in 3D. On the contrary, the 2D solitons are shown to be stable in a certain parameter range; hence the damping and parametric driving are capable of suppressing the nonlinear blowup and dispersive decay of solitons in two dimensions. The negative feedback loop occurs via the enslaving of the soliton's phase, coupled to the driver, to its amplitude and width.Comment: 4 pages; 1 figur

Bases orthonormées d'ondelettes splines linéaires adaptées à une grille irrégulière

- Dans cet article, nous proposons une construction d'une base d'ondelettes orthonormée correspondant à une analyse par des fonctions B-splines non-uniformes de degré un. Nous montrons que le passage d'une échelle à l'autre est réalisé par un banc de filtres caractérisé par la localisation des données dans la séquence initiale. Les expressions explicites des coefficients des filtres sont fournies. Les fonctions d'échelles et d'ondelettes obtenues ne sont plus des translatées et des dilatées d'une seule fonction. Ceci nous permet de proposer une définition de l'analyse multirésolution d'un signal échantillonné à des instants irréguliers