L'anti­correcteur : outil d'évaluation positive de l'orthographe et de la grammaire

International audienceThis study aims at testing out a new form of evaluation for spell and grammar checking. A new tool, called "anti-correcteur", was integrated in Cordial, a French spell and grammar checker, for measuring success rates in common spelling difficulties defined according to literature in French language teaching and corpus-based analysis. This module proposes to assess spelling skills not only against errors, but also by taking successes into account. This paper presents a first experiment of such a positive evaluation by exploring results given by the "anti-correcteur" applied on a diversified corpus in terms of level of literacy and genre.L'objectif de cette étude est d'expérimenter l'intégration d'une nouvelle forme d'évaluation dans un correcteur orthographique et grammatical. L'« anti-correcteur » a pour objet de mesurer le taux de réussites orthographiques et grammaticales d'un texte sur certains points jugés difficiles selon la littérature et une observation d'erreurs en corpus. L'évaluation du niveau d'écriture ne se base plus uniquement sur les erreurs commises, mais également sur les réussites réalisées. Une version bêta de ce nouveau mode d'évaluation positive a été intégré dans le correcteur Cordial. Cet article a pour but de discuter de l'intérêt de ce nouveau rapport à l'orthographe et de présenter quelques premiers éléments d'analyse résultant de l'application de l'anti-correcteur sur un corpus de productions variées en matière de niveau d'écriture et genre discursif

Développement d’équations pour la partie advective du transport d’un traceur injecté dans un puits avec prise en compte de la distorsion des lignes d’écoulement par le puits

Résumé Les méthodes d’interprétation d’essais de traceur sont souvent basées sur des équations faisant l’hypothèse d’un écoulement régional naturel rectiligne uniforme. Le but de ce projet était de proposer de nouvelles équations pour la partie advective du transport d’un contaminant, en prenant en compte la distorsion des lignes d’écoulement au voisinage du puits d’injection. Le potentiel complexe du flux lors d’un essai de traceur a été obtenu par superposition de celui d’un flux naturel rectiligne uniforme déformé par la présence d’un puits au repos et celui d’un flux radial correspondant à une injection isotrope seule. Les équations ont été développées pour un plan horizontal et le potentiel complexe trouvé a pu être dérivé en champ de vitesse, puis en une formule reliant la position du front du panache d’injection et le temps écoulé depuis le début de celle-ci. Ces nouvelles équations ont ensuite été testées par simulations numériques. Un aquifère plan a été modélisé en 2D et paramétré pour réaliser numériquement du traçage de particules et de l’advection-dispersion en un temps raisonnable. Ce modèle a permis d’effectuer des essais de traceur numériques et les résultats sur le temps nécessaire pour pomper intégralement le panache de traceur préalablement injecté a été comparé à celui calculé à l’aide des nouvelles équations et celui calculé par d’anciennes équations ne prenant pas en compte la distorsion du champ de vitesse par la présence du puits. Les résultats ont montré que les nouvelles équations sont significativement plus précises, notamment lorsque la vitesse d’injection est plus faible que la vitesse d’écoulement régional naturel, pour un diamètre de puits suffisamment grand et au voisinage du puits d’injection. Trois formes de panache ont pu être visualisées numériquement : ces formes dépendent de la valeur d’un paramètre � comparant la composante de la vitesse relative à l’injection au puits et la composante relative à l’écoulement régional naturel. ----------Abstract Methods for interpreting tracer tests often rely on equations assuming a natural regional flow which is straight and uniform. The main purpose of this project was to suggest new equations for the advective part of contaminant transport, by including the flow lines distortion occuring in the vicinity of the injection well. The complex potential of the flow during a tracer test was calculated by superimposing the complex potential of a natural, straight and uniform flow distorted by the presence of a passive well, and the complex potential of a radial flow corresponding to an isotropic injection alone. The equations were developed for a horizontal plan and the calculated complex potential was then derived in a groundwater velocity field, and after that in a formula connecting the position of the advancing front of the tracer plume to the time passed since the beginning of the injection. These new equations were then tested with numerical simulations. A two-dimensional aquifer plan was modeled and set in order to numerically realise particle tracking and advection-dispertion within a reasonable calculation time. This model enabled the proceeding of numerical tracer tests and the resulting time necessary to fully pump the tracer plume previously injected was compared to the one calculated with the new equations and the one calculated with former equations that neglected the impact of the presence of the well on the groundwater flow field. The results showed that the new equations are significantly more precise, in particular when the injection rate is sufficiently low compared to the natural regional flow rate, with a well diameter relatively large and in the vicinity of the injection well. Three different plume shapes could be visualized numerically, and those shapes depend on the value of a parameter � which compares the velocity component caused by the injection in the well and the component caused by the natural regional flow

On the asymmetry of wh-doubling in varieties of German and Dutch

Theoretical and Experimental Linguistic

An Optical Readout TPC (O-TPC) for Studies in Nuclear Astrophysics With Gamma-Ray Beams at HIgS

We report on the construction, tests, calibrations and commissioning of an Optical Readout Time Projection Chamber (O-TPC) detector operating with a CO2(80%) + N2(20%) gas mixture at 100 and 150 Torr. It was designed to measure the cross sections of several key nuclear reactions involved in stellar evolution. In particular, a study of the rate of formation of oxygen and carbon during the process of helium burning will be performed by exposing the chamber gas to intense nearly mono-energetic gamma-ray beams at the High Intensity Gamma Source (HIgS) facility. The O-TPC has a sensitive target-drift volume of 30x30x21 cm^3. Ionization electrons drift towards a double parallel grid avalanche multiplier, yielding charge multiplication and light emission. Avalanche induced photons from N2 emission are collected, intensified and recorded with a Charge Coupled Device (CCD) camera, providing two-dimensional track images. The event's time projection (third coordinate) and the deposited energy are recorded by photomultipliers and by the TPC charge-signal, respectively. A dedicated VME-based data acquisition system and associated data analysis tools were developed to record and analyze these data. The O-TPC has been tested and calibrated with 3.183 MeV alpha-particles emitted by a 148Gd source placed within its volume with a measured energy resolution of 3.0%. Tracks of alpha and 12C particles from the dissociation of 16O and of three alpha-particles from the dissociation of 12C have been measured during initial in-beam test experiments performed at the HIgS facility at Duke University. The full detection system and its performance are described and the results of the preliminary in-beam test experiments are reported.Comment: Supported by the Richard F. Goodman Yale-Weizmann Exchange Program, ACWIS, NY, and USDOE grant Numbers: DE-FG02-94ER40870 and DE-FG02-97ER4103

Barrier and internal wave contributions to the quantum probability density and flux in light heavy-ion elastic scattering

We investigate the properties of the optical model wave function for light heavy-ion systems where absorption is incomplete, such as $\alpha + ^{40}$Ca and $\alpha + ^{16}$O around 30 MeV incident energy. Strong focusing effects are predicted to occur well inside the nucleus, where the probability density can reach values much higher than that of the incident wave. This focusing is shown to be correlated with the presence at back angles of a strong enhancement in the elastic cross section, the so-called ALAS (anomalous large angle scattering) phenomenon; this is substantiated by calculations of the quantum probability flux and of classical trajectories. To clarify this mechanism, we decompose the scattering wave function and the associated probability flux into their barrier and internal wave contributions within a fully quantal calculation. Finally, a calculation of the divergence of the quantum flux shows that when absorption is incomplete, the focal region gives a sizeable contribution to nonelastic processes.Comment: 16 pages, 15 figures. RevTeX file. To appear in Phys. Rev. C. The figures are only available via anonynous FTP on ftp://umhsp02.umh.ac.be/pub/ftp_pnt/figscat

Unambiguous Identification of the Second 2+ State in 12C and the Structure of the Hoyle State

The second 2+ state of 12C, predicted over fifty years ago as an excitation of the Hoyle state, has been unambiguously identified using the 12C(g,a_0)8Be reaction. The alpha particles produced by the photodisintegration of 12C were detected using an Optical Time Projection Chamber (O-TPC). Data were collected at beam energies between 9.1 and 10.7 MeV using the intense nearly mono-energetic gamma-ray beams at the HIgS facility. The measured angular distributions determine the cross section and the E1-E2 relative phases as a function of energy leading to an unambiguous identification of the second 2+ state in 12C at 10.03(11) MeV, with a total width of 800(130) keV and a ground state gamma-decay width of 60(10) meV; B(E2: 2+ ---> gs) = 0.73(13) e2fm4 [or 0.45(8) W.u.]. The Hoyle state and its rotational 2+ state that are more extended than the ground state of 12C presents a challenge and constraints for models attempting to reveal the nature of three alpha particle states in 12C. Specifically it challenges the ab-initio Lattice Effective Field Theory (L-EFT) calculations that predict similar r.m.s. radii for the ground state and the Hoyle state.Comment: Accepted for Publication in the Physical Review Lette