On-line cursive handwritten character recognition using Hidden Markov Models

In this paper, we present an on-line handwritten character recognition system which is based on structured and logical modeling of handwriting using Hidden Markov Models. After some specific preprocessing, we extract two differen t classes of primitives which represent the two main aspects of handwriting : th e dynamic aspect for the notion of trajectory of the pen tip and the static aspec t for the notion of global geometry of the letter. We make an initial training to adjust the probabilities of each Hidden Markov Model. Then, the recognition system computes the probabilities of generation by each model of the letter to b e interpreted. This performs a clustering process based on similarity.Cet article présente un système de reconnaissance en ligne de lettres cursives isolées qui s'appuie sur une modélisation structurée et logique des lettres (amorce, corps, ligature,...) par l'intermédiaire de modèles de Markov cachés. Après différents prétraitements spécifiques, on opère une segmentation dynamique des lettres en primitives locales représentatives de la trajectoire de la pointe du stylet (aspect gestuel), associées à des primitives de nature plus globale représentatives de la géométrie du tracé (aspect visuel). Une phase d'apprentissage est ensuite réalisée sur chaque modèle associé à chaque type de lettre. Lors de la reconnaissance, le système va estimer les probabilités de génération de la lettre à reconnaître pour chaque modèle. On effectue ainsi une classification basée sur un critère de ressemblance

Competition of lattice and basis for alignment of nematic liquid crystals

Due to elastic anisotropy, two-dimensional patterning of substrates can promote weak azimuthal alignment of adjacent nematic liquid crystals. Here we consider how such alignment can be achieved using a periodic square lattice of circular or elliptical motifs. In particular, we examine ways in which the lattice and motif can combine to favor differing orientations. Using Monte Carlo simulation and continuum elasticity we find, for circular motifs, that the coverage fraction controls both the polar anchoring angle and a transition in the azimuthal orientation. If the circles are generalized to ellipses, arbitrary control of the effective easy axis and effective anchoring potential becomes achievable by appropriate tuning of the ellipse motif relative to the periodic lattice patterning. This has possible applications in both monostable and bistable liquid crystal device contexts

New insights into the structure and chemistry of Titan's tholins via C-13 and N-15 solid state nuclear magnetic resonance spectroscopy

Tholins are complex C,N-containing organic compounds produced in the laboratory. They are considered to provide materials that are analogous to those responsible for the haze observed in Titan’s atmosphere. These compounds present an astrobiological interest due to their ability to release amino acids upon hydrolysis. Their chemical structure has been investigated using a large number of techniques. However, to date no detailed nuclear magnetic resonance (NMR) study has been performed on these materials despite the high potential of this technique for investigating the environment of given nuclei. Here 13C and 15N solid state NMR spectroscopy was applied to obtain new insights into the chemical structure of tholins produced through plasma discharge in gaseous N2single bondCH4 mixtures designed to simulate the atmosphere of Titan. Due to the low natural abundance of these isotopes, a 13C and 15N-enriched tholin sample was synthesized using isotopically enriched gas precursors. Various pulse sequences including 13C and 15N single pulse, 1Hsingle bond13C and 1Hsingle bond15N cross-polarisation and 1Hsingle bond15Nsingle bond13C double cross-polarisation were used. These techniques allowed complete characterisation of the chemical and structural environments of the carbon and nitrogen atoms. The NMR assignments were supplemented and confirmed by ab initio electronic structure calculations for model structures and molecular fragments

Simulation Modifies Prehension: Evidence for a Conjoined Representation of the Graspable Features of an Object and the Action of Grasping It

Movement formulas, engrams, kinesthetic images and internal models of the body in action are notions derived mostly from clinical observations of brain-damaged subjects. They also suggest that the prehensile geometry of an object is integrated in the neural circuits and includes the object's graspable characteristics as well as its semantic properties. In order to determine whether there is a conjoined representation of the graspable characteristics of an object in relation to the actual grasping, it is necessary to separate the graspable (low-level) from the semantic (high-level) properties of the object. Right-handed subjects were asked to grasp and lift a smooth 300-g cylinder with one hand, before and after judging the level of difficulty of a “grasping for pouring” action, involving a smaller cylinder and using the opposite hand. The results showed that simulated grasps with the right hand exert a direct influence on actual motor acts with the left hand. These observations add to the evidence that there is a conjoined representation of the graspable characteristics of the object and the biomechanical constraints of the arm

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

Relations between C9orf72 expansion size in blood, age at onset, age at collection and transmission across generations in patients and presymptomatic carriers

A (GGGGCC) n repeat expansion in C9orf72 gene is the major cause of frontotemporal dementia (FTD) and amyotrophic lateral sclerosis (ALS). The relations between the repeats size and the age at disease onset (AO) or the clinical phenotype (FTD vs. ALS) were investigated in 125 FTD, ALS, and presymptomatic carriers. Positive correlations were found between repeats number and the AO (p < 10 e−4 ) but our results suggested that the association was mainly driven by age at collection (p < 10 e−4 ). A weaker association was observed with clinical presentation (p = 0.02), which became nonsignificant after adjustment for the age at collection in each group. Importantly, repeats number variably expanded or contracted over time in carriers with multiple blood samples, as well as through generations in parent-offspring pairs, conversely to what occurs in several expansion diseases with anticipation at the molecular level. Finally, this study establishes that measure of repeats number in lymphocytes is not a reliable biomarker predictive of the AO or disease outcome in C9orf72 long expansion carriers

Coxsackie-adenovirus receptor expression is enhanced in pancreas from patients with type 1 diabetes

Objectives: One of the theories connecting enterovirus (EV) infection of human islets with type 1 diabetes (T1D) is the development of a fertile field in the islets. This implies induction of appropriate proteins for the viral replication such as the coxsackie–adenovirus receptor (CAR). The aim of this study was to investigate to what extent CAR is expressed in human islets of Langerhans, and what conditions that would change the expression. Design: Immunohistochemistry for CAR was performed on paraffin-embedded pancreatic tissue from patients with T1D (n=9 recent onset T1D, n=4 long-standing T1D), islet autoantibody-positive individuals (n=14) and non-diabetic controls (n=24) individuals. The expression of CAR was also examined by reverse transcription PCR on microdissected islets (n=5), exocrine tissue (n=5) and on explanted islets infected with EV or exposed to chemokines produced by EV-infected islet cells. Results: An increased frequency of patients with T1D and autoantibody-positive individuals expressed CAR in the pancreas (p<0.039). CAR staining was detected more frequently in pancreatic islets from patients with T1D and autoantibody-positive subjects (15/27) compared with (6/24) non-diabetic controls (p<0.033). Also in explanted islets cultured in UV-treated culture medium from coxsackievirus B (CBV)-1-infected islets, the expression of the CAR gene was increased compared with controls. Laser microdissection of pancreatic tissue revealed that CAR expression was 10-fold higher in endocrine compared with exocrine cells of the pancreas. CAR was also expressed in explanted islets and the expression level decreased with time in culture. CBV-1 infection of explanted islets clearly decreased the expression of CAR (p<0.05). In contrast, infection with echovirus 6 did not affect the expression of CAR. Conclusions: CAR is expressed in pancreatic islets of patients with T1D and the expression level of CAR is increased in explanted islets exposed to proinflammatory cytokines/chemokines produced by infected islets. T1D is associated with increased levels of certain chemokines/cytokines in the islets and this might be the mechanism behind the increased expression of CAR in TID islets

Integration of an on-line handwriting recognition system in a smart phone device

International audienceThis paper presents the evolving of our academic development to a technology driven application: the integration of an unconstraint cursive on-line handwritten character recognition system into a smart phone device. The ultimate goal of this work is to implement an accuracy handwriting recognizer into mobile devices with limited computing and memory resources. A hierarchical fuzzy modeling is used to obtain a compact and robust knowledge representation and the decision process is based on an adapted fuzzy inference system to reduce computing without decreasing the performances. We describe in this paper the basic architecture of the recognition system called " ResifCar " , its practical adaptation to the mobile device constraints and the recognition rates both on cursive isolated letters (91.9%) and on isolated digits (92.3%) in a writer independent context based on 100 different writers

PEAPL-Lab - Plateforme Europ\ue9enne d'Apprentissage Personnalis\ue9 des Langues

Le projet PEAPL (Plateforme Europ\ue9enne d'Apprentissage Personnalis\ue9 des Langues-European Platform for Personalized Learning of Languages) se propose de d\ue9velopper un apprentissage adaptatif dans l\u2019enseignement des langues dans le but d\u2019une inclusion r\ue9ussie des apprenants allophones. Le projet comporte 5 productions intellectuelles : 1. D\ue9veloppement du module d\u2019Adaptive Learning ; 2. La plate-forme web multilingue GamesHub ; 3. Les g\ue9n\ue9rateurs d\u2019exercices ASKER ; 4. Les ressources p\ue9dagogiques incluant \ue9galement les r\ue9f\ue9rentiels par langue et par terrain d\u2019exp\ue9rimentation de la plate-forme; 5. La bo\ueete \ue0 outils \ue0 destination des enseignants afin de se former \ue0 l\u2019utilisation de PEAPL. Deux plateformes seront d\ue9velopp\ue9es en parall\ue8le avec le but de converger \ue0 la fin du contrat pour : - permettre l\u2019exploitation des traces des apprenants par l\u2019outil d\u2019adaptive learning afin de cr\ue9er la personnalisation des parcours ; - \ue9largir les possibilit\ue9s p\ue9dagogiques offertes \ue0 l\u2019enseignant