First degree of characterization for handwriting

Like all products of human activity, handwriting exhibits extreme variability. We are analysing this variability before initiating a text recognition process, a first degre e of characterization for handwriting. In the case of handwriting consisting of few words, such as the literal amount of cheques, this first degree can be obtained fo r each word independent of its semantic signification by extracting a small numbe r of measures. Based on the analysis of 989 handwritten amounts from cheques, it is shown that these measures are weakly correlated and define a variability space of non-uniform density, which suggests the possibility of classification of handwriting into a set of several families.L'écriture manuscrite, comme la plupart des productions de l'activité humaine, présente une étonnante variabilité. Nous étudions cette variabilité afin d'obtenir, préalablement à sa reconnaissance, un premier degré de caractérisation de l'écriture manuscrite. Sur des écrits possèdant peu de mots, ce premier degré de caractérisation peut être déterminé, au niveau de chaque mot, par un petit nombre d'observations largement indépendantes de leur contenu sémantique, et, par suite, propres à la main du scripteur. Une étude statistique portant sur 980 montants littéraux de chèques montre que ces observations sont peu corrélées entre elles: elles définissent un espace de variabilité inégalement dense, laissant ainsi apparaître la possibilité d'un regroupement des écritures en familles

Percolation model for structural phase transitions in Li1−x_{1-x}Hx_xIO3_3 mixed crystals

A percolation model is proposed to explain the structural phase transitions found in Li$_{1-x}$H$_x$IO$_3$ mixed crystals as a function of the concentration parameter $x$. The percolation thresholds are obtained from Monte Carlo simulations on the specific lattices occupied by lithium atoms and hydrogen bonds. The theoretical results strongly suggest that percolating lithium vacancies and hydrogen bonds are indeed responsible for the solid solution observed in the experimental range $0.22 < x < 0.36$.Comment: 4 pages, 2 figure

Linear feature detection on SAR images

We aim at defining an automatic or semi-automatic method for the extraction of road network in radar images . To realize the low level detection, line detectors are proposed . They extract linear features which become candidates for road segments . Two loca l structure detectors are developed taking into account the speckle phenomenon, and an extensive study of their behaviour as wel l as the behaviour of the fusion of their responses is made (theoretical detection and false alarm probabilities are evaluated an d computed on real images) . One of this detector is based on an edge detector widely used in coherent imagery, and the secon d one is based on a specific adapted filtering . The line detection is eventually made by the fusion of both detector responses .Dans l'objectif d'établir une méthode de détection semi-automatique du réseau routier sur des images radar, des détecteur de lignes sont développés. Ils ont pour but d'extraire des structures linéaires de l'image, qui seront ensuite considérées comme des segments « candidats routes ». Deux détecteurs de lignes prenant en compte les statistiques du speckle sont proposés, et une étude détaillée de leurs comportements et du comportement de leur fusion (probabilités de détection et de fausse alarme) est réalisée. L'un de ces détecteurs est fondé sur un détecteur de contours largement utilisé en imagerie radar, et l'autre plus original sur un filtrage adapté. La détection de lignes est finalement réalisée par la fusion des réponses de ces deux détecteurs

European integration assessed in the light of the 'rules vs. standards debate'

The interplay of various legal systems in the European Union (EU) has long triggered a debate on the tension between uniformity and diversity of Member States' (MS) laws. This debate takes place among European legal scholars and is also paralleled by economic scholars, e.g. in the ambit of the 'theory of federalism'. This paper takes an innovative perspective on the discrepancy between 'centralized' and 'decentralized' law-making in the EU by assessing it with the help of the rules versus standards debate. When should the EU legislator grant the national legislator leeway in the formulation of new laws and when should all be fixed ex ante at European level? The literature on the 'optimal shape of legal norms' shall be revisited in the light of law-making in the EU, centrally dealing with the question how much discretion shall be given to the national legislator; and under which circumstances. This paper enhances the established decisive factors for the choice of a rule or a standard in a national setting (complexity, volatility, judges' specialization and frequency of application) by two new crucial factors (switching costs and the benefit of uniformity in terms of information costs) in order to assess law-making policies at EU level

Bayesian Action–Perception Computational Model: Interaction of Production and Recognition of Cursive Letters

In this paper, we study the collaboration of perception and action representations involved in cursive letter recognition and production. We propose a mathematical formulation for the whole perception–action loop, based on probabilistic modeling and Bayesian inference, which we call the Bayesian Action–Perception (BAP) model. Being a model of both perception and action processes, the purpose of this model is to study the interaction of these processes. More precisely, the model includes a feedback loop from motor production, which implements an internal simulation of movement. Motor knowledge can therefore be involved during perception tasks. In this paper, we formally define the BAP model and show how it solves the following six varied cognitive tasks using Bayesian inference: i) letter recognition (purely sensory), ii) writer recognition, iii) letter production (with different effectors), iv) copying of trajectories, v) copying of letters, and vi) letter recognition (with internal simulation of movements). We present computer simulations of each of these cognitive tasks, and discuss experimental predictions and theoretical developments

ÉTUDE DES PRODUITS CHARGÉS DE LA RÉACTION 9Be + d A TRÈS BASSE ÉNERGIE (100 A 200 keV)

Les distributions angulaires des protons, tritons et alphas sont fortement anisotropes et non symétriques par rapport à un plan perpendiculaire au faisceau incident. Les quatre courbes obtenues peuvent être interprétées par la contribution de deux niveaux de parité opposée du noyau composé.The proton, triton and alpha angular distributions are strongly anisotropic and are not symmetric with respect to the plane perpendicular to the incident beam. The four curves obtained can be accounted for by the interference of two levels of opposite parity of the compound nucleus

Multispectral Imaging in Multimedia

this paper we investigate the colorimetric simulation of a scene as viewed under different illuminants. Applied to fine arts paintings, museological objects, jewelry, textiles, etc., such simulations could be of particular interest as a multimedia application. It is well known that the appearance of an object or a scene may change considerably when the illuminant changes, due to physical and psychophysical effects. These effects are taken into account in most colour appearance models in a somewhat heuristic manner. However, such models can not predict correctly changes for arbitrary illuminants, one important reason for this being metamerism. To be able to predict quantitatively the physical phenomena involved in a change between any illuminants, a more complete spectral description of the illuminants and the scene reflectances is needed. The acquisition of multispectral images is thus required. A multispectral image is an image where each pixel contains information about the spectral reflectance of the imaged scene. Multispectral images carry information about a number of spectral bands: from three components per pixel for colour images to several hundreds of bands for hyperspectral images. Multispectral imaging is relevant to several domains of application, such as remote sensing [1], physics, analysis of museological objects [2], cosmetics, medicine [3], high-accuracy colour printing, or computer graphics [4]. Hyperspectral image acquisition systems are complex and expensive, limiting their current use mainly to remote sensing applications. Multispectral scanners are mostly based on a point-scan scheme [5], and are thus too slow for our applications

Equilibrium Dynamics in a Two-Sector OLG Model with Liquidity Constraint

We study a two-sector OLG economy in which a share of old age consumption expenditures must be paid out of money balances and we appraise its dynamic features. We first show that competitive equilibrium is dynamically efficient if and only if the share of capital on total income is large enough while a steady state capital per capita above its Golden Rule level is not consistent with a binding liquidity constraint. We thus focus on the gross substitutability in consumption and on dynamic efficiency assumptions and show that, gathered together, they ensure the local determinacy of equilibrium and, as a consequence, rule out sunspot fluctuations. In addition, we prove that the unique steady state may change its stability from a saddle configuration to a source one (undergoing a flip bifurcation) for a capital intensive investment good as well as for a capital intensive consumption good, when the elasticity of the interest rate is set low enough. However, when the investment good is not too capital intensive, the flip bifurcation turns out to be compatible with high elasticities of the interest rate too. Analogous results within dynamic efficiency are found in the non-monetary model, the existence of a flip bifurcation requiring now a capital intensive investment good. Eventually, under dynamic inefficiency, in the non-monetary economy local indeterminacy may instead appear, either through a Hopf bifurcation or through a flip one, and its scope improves as soon as the consumption good becomes more and more capital intensive