David Langlois

Glimpses into the early Universe (2009)

Langlois, David

This contribution gives a brief overview of the theoretical ideas underlying our current understanding of the early Universe. Confronting the predictions of the early Universe models with...

Primordial perturbations and non-Gaussianities from modulated trapping (2009)

Langlois, David, Sorbo, Lorenzo

We propose a new mechanism to generate primordial curvature perturbations, based on the resonant production of particles during inflation. It is known that this phenomenon can trap the inflaton for a...

Multi-field DBI inflation: introducing bulk forms and revisiting the gravitational wave constraints (2009)

Langlois, David, Renaux-Petel, Sebastien, Steer, Daniele A.

We study multi-field Dirac-Born-Infeld (DBI) inflation models, taking into account the NS-NS and R-R bulk fields present in generic flux compactifications. We compute the second-order action, which...

New Confidence Measures for Statistical Machine Translation (2009)

Raybaud, Sylvain, Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

A confidence measure is able to estimate the reliability of an hypothesis provided by a machine translation system. The problem of confidence measure can be seen as a process of testing : we want to...

New Confidence Measures for Statistical Machine Translation (2009)

Raybaud, Sylvain, Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

A confidence measure is able to estimate the reliability of an hypothesis provided by a machine translation system. The problem of confidence measure can be seen as a process of testing : we want to...

New Confidence Measures for Statistical Machine Translation (2009)

Raybaud, Sylvain, Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

A confidence measure is able to estimate the reliability of an hypothesis provided by a machine translation system. The problem of confidence measure can be seen as a process of testing : we want to...

Efficient Combination of Confidence Measures for Machine Translation (2009)

Raybaud, Sylvain, Langlois, David, Smaïli, Kamel

We present in this paper a twofold contribution to Confidence Measures for Machine Translation. First, in order to train and test confidence measures, we present a method to automatically build...

Word- and sentence-level confidence measures for machine translation (2009)

Raybaud, Sylvain, Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

A machine translated sentence is seldom completely correct. Confidence measures are designed to detect incorrect words, phrases or sentences, or to provide an estimation of the probability of...

Efficient Combination of Confidence Measures for Machine Translation (2009)

Raybaud, Sylvain, Langlois, David, Smaïli, Kamel

We present in this paper a twofold contribution to Confidence Measures for Machine Translation. First, in order to train and test confidence measures, we present a method to automatically build...

Word- and sentence-level confidence measures for machine translation (2009)

Raybaud, Sylvain, Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

A machine translated sentence is seldom completely correct. Confidence measures are designed to detect incorrect words, phrases or sentences, or to provide an estimation of the probability of...

Early Universe: inflation and cosmological perturbations (2008)

Langlois, David

After a brief summary of general relativity and cosmology, we present the basic concepts underlying inflation, the currently best motivated models for the early Universe. We describe the simplest...

Non-linear isocurvature perturbations and non-Gaussianities (2008)

Langlois, David, Vernizzi, Filippo, Wands, David

We study non-linear primordial adiabatic and isocurvature perturbations and their non-Gaussianity. After giving a general formulation in the context of an extended delta N-formalism, we analyse in...

Cosmological perturbations from multi-field inflation (2008)

Langlois, David

We briefly review the standard derivation of the spectra of cosmological perturbations in the simplest models of inflation. We then consider models with several scalar fields, described by...

Primordial perturbations and non-Gaussianities in DBI and general multi-field inflation (2008)

Langlois, David, Renaux-Petel, Sebastien, Steer, Daniele A, Tanaka, Takahiro

We study cosmological perturbations in general inflation models with multiple scalar fields and arbitrary kinetic terms, with special emphasis on the multi-field extension of Dirac-Born-Infeld (DBI)...

Primordial perturbations and non-Gaussianities in DBI and general multi-field inflation (2008)

Langlois, David, Renaux-Petel, Sebastien, Steer, Daniele A., Tanaka, Takahiro

We study cosmological perturbations in general inflation models with multiple scalar fields and arbitrary kinetic terms, with special emphasis on the multi-field extension of Dirac-Born-Infeld (DBI)...

Primordial Fluctuations and Non-Gaussianities in Multifield Dirac-Born-Infeld Inflation (2008)

Langlois, David, Renaux-Petel, Sebastien, Steer, Daniele A, Tanaka, Takahiro

We study Dirac-Born-Infeld (DBI) inflation models with multiple scalar fields. We show that the adiabatic and entropy modes propagate with a common effective sound speed and are thus amplified at the...

Primordial fluctuations and non-Gaussianities in multi-field DBI inflation (2008)

Langlois, David, Renaux-Petel, Sebastien, Steer, Daniele A., Tanaka, Takahiro

We study Dirac-Born-Infeld (DBI) inflation models with multiple scalar fields. We show that the adiabatic and entropy modes propagate with a common effective sound speed and are thus amplified at the...

Perturbations in generalized multi-field inflation (2008)

Langlois, David, Renaux-Petel, Sébastien

We study the linear perturbations of multi-field inflationary models governed by a Lagrangian which is a general function of the scalar fields and of a global kinetic term combining their spacetime...

Une alternative aux modèles de traduction statistique d'IBM : Les triggers inter-langues (2008)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

Dans cet article, nous présentons une nouvelle approche pour la traduction automatique fondée sur les triggers inter-langues. Dans un premier temps, nous expliquons le concept de triggers...

Phrase-Based Machine Translation based on Simulated Annealing (2008)

Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

In this paper, we propose a new phrase-based translation model based on inter-lingual triggers. The originality of our method is double. First we identify common source phrases. Then we use...

Une alternative aux modèles de traduction statistique d'IBM : Les triggers inter-langues (2008)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

Dans cet article, nous présentons une nouvelle approche pour la traduction automatique fondée sur les triggers inter-langues. Dans un premier temps, nous expliquons le concept de triggers...

Phrase-Based Machine Translation based on Simulated Annealing (2008)

Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

In this paper, we propose a new phrase-based translation model based on inter-lingual triggers. The originality of our method is double. First we identify common source phrases. Then we use...

Discovering Phrases in Machine Translation by Simulated Annealing (2008)

Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

In this paper, we propose a new phrase-based translation model based on inter-lingual triggers. The originality of our method is double. First we identify common source. Then we use inter-lingual...

Discovering Phrases in Machine Translation by Simulated Annealing (2008)

Lavecchia, Caroline, Langlois, David, Smaïli, Kamel

In this paper, we propose a new phrase-based translation model based on inter-lingual triggers. The originality of our method is double. First we identify common source. Then we use inter-lingual...

Long-Wavelength Iteration Scheme and Scalar-Tensor Gravity (2007)

G. L. Comer, Nathalie Deruelle, Centre National, Recherche Scientifique, ...

Inhomogeneous and anisotropic cosmologies are modeled withing the framework of scalar-tensor gravity theories. The inhomogeneities are calculated to third-order in the so-called long-wavelength...

Cosmological Perturbations seeded by Topological Defects: Setting the Initial Conditions (2007)

Nathalie Deruelle, David Langlois, Jean-Philippe Uzan

We consider a perfectly homogeneous and isotropic universe which undergoes a sudden phase transition. If the transition produces topological defects, which we assume, perturbations in the geometry...

Dipole Anisotropy from an Entropy Gradient (2007)

David Langlois, Tsvi Piran

It is generally accepted that the observed CMBR dipole arises from the motion of the local group relative to the CMBR frame. An alternative interpretation is that the dipole results from an...

Cosmic Microwave Background Dipole induced by double inflation (2007)

David Langlois, Centre National, Recherche Scientifique

The observed CMBR dipole is generally interpreted as the consequence of the peculiar motion of the Sun with respect to the reference frame of the CMBR. This article proposes an alternative...

Kaluza-Klein braneworld cosmology with static internal dimensions (2007)

Kanno, Sugumi, Langlois, David, Sasaki, Misao, Soda, Jiro

We investigate the Kaluza-Klein braneworld cosmology from the point of view of observers on the brane. We first generalize the Shiromizu-Maeda-Sasaki (SMS) equations to higher dimensions. As an...

Cosmological evolution of regularized branes in 6D warped flux compactifications (2007)

Minamitsuji, Masato, Langlois, David

We study the cosmological evolution of extended branes in 6D warped flux compactification models. The branes are endowed with the three ordinary spatial dimensions, which are assumed to be...

Using inter-lingual triggers for Machine translation (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David, Haton, Jean-Paul

In this paper, we present the idea of cross-lingual triggers. We exploit this formalism in order to build up a bilingual dictionary for machine translation. We describe the idea of cross-lingual...

Building Parallel Corpora from Movies (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

This paper proposes to use DTW to construct parallel corpora from difficult data. Parallel corpora are considered as raw material for machine translation (MT), frequently, MT systems use European or...

Using inter-lingual triggers for Machine translation (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David, Haton, Jean-Paul

In this paper, we present the idea of cross-lingual triggers. We exploit this formalism in order to build up a bilingual dictionary for machine translation. We describe the idea of cross-lingual...

Building Parallel Corpora from Movies (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

This paper proposes to use DTW to construct parallel corpora from difficult data. Parallel corpora are considered as raw material for machine translation (MT), frequently, MT systems use European or...

Building a bilingual dictionary from movie subtitles based on inter-lingual triggers (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

This paper focuses on two aspects of Machine Translation: parallel corpora and translation model. First, we present a method to automatically build parallel corpora from subtitle files. We use...

Building a bilingual dictionary from movie subtitles based on inter-lingual triggers (2007)

Lavecchia, Caroline, Smaïli, Kamel, Langlois, David

This paper focuses on two aspects of Machine Translation: parallel corpora and translation model. First, we present a method to automatically build parallel corpora from subtitle files. We use...

Improving language models by using distant information (2007)

Brun, Armelle, Langlois, David, Smaïli, Kamel

This study examines how to take originally advantage from distant information instatistical language models. We show that it is possible to use n-gram models considering histories different from...

Improving language models by using distant information (2007)

Brun, Armelle, Langlois, David, Smaïli, Kamel

This study examines how to take originally advantage from distant information instatistical language models. We show that it is possible to use n-gram models considering histories different from...

Rotating spacetimes with a cosmological constant (2006)

Charmousis, Christos, Langlois, David, Steer, Daniele, Zegers, Robin

We develop solution-generating techniques for stationary metrics with one angular momentum and axial symmetry, in the presence of a cosmological constant and in arbitrary spacetime dimension. In...

Nonlinear perturbations of cosmological scalar fields (2006)

Langlois, David, Vernizzi, Filippo

We present a covariant formalism for studying nonlinear perturbations of scalar fields. In particular, we consider the case of two scalar fields and introduce the notion of adiabatic and isocurvature...

Is our Universe brany ? (2005)

Langlois, David

In brane-worlds, our universe is assumed to be a submanifold, or brane, embedded in a higher-dimensional bulk spacetime. Focusing on scenarios with a curved five-dimensional bulk spacetime, I discuss...

Experiments on Building Language Resources for Multi-Modal Dialogue Systems (2004)

Romary, Laurent, Todirascu, Amalia, Langlois, David

The paper presents the experiments made to adapt and to synchronise the linguistic resources of the French language processing modules integrated in the MIAMM prototype, designed to handle...

Experiments on Building Language Resources for Multi-Modal Dialogue Systems (2004)

Romary, Laurent, Todirascu, Amalia, Langlois, David

The paper presents the experiments made to adapt and to synchronise the linguistic resources of the French language processing modules integrated in the MIAMM prototype, designed to handle...

Bulk gravitons from a cosmological brane (2003)

Langlois, David, Sorbo, Lorenzo

We investigate the emission of gravitons by a cosmological brane into an Anti de Sitter five-dimensional bulk spacetime. We focus on the distribution of gravitons in the bulk and the associated...

Cosmology in a brane-universe (2003)

Langlois, David

This contribution presents the cosmological models with extra dimensions that have been recently elaborated, which assume that ordinary matter is confined on a surface, called brane, embedded in a...

Brane cosmology: an introduction (2002)

Langlois, David

These notes give an introductory review on brane cosmology. This subject deals with the cosmological behaviour of a brane-universe, i.e. a three-dimensional space, where ordinary matter is confined,...

Relativistic solution of Lordanskii problem in multi-constituent superfluid mechanics Context Sensitive Links (2002)

Prix, Reinhard, Carter, Brandon, Langlois, David

Flow past a line vortex in a simple perfect fluid or superfluid gives rise to a transverse Magnus force that is given by the well known Joukowski lift formula. The problem of generalising this to...

Bogomol’nyi limit for magnetic vortices in a rotating superconductor (2000)

Prix, Reinhard, Carter, Brandon, Langlois, David

This work is the sequel to a previous investigation of stationary and cylindrically symmetric vortex configurations for simple models representing an incompressible nonrelativistic superconductor in...

Energy of magnetic vortices in a rotating superconductor (2000)

Prix, Reinhard, Carter, Brandon, Langlois, David

We carry out a systematic analytic investigation of stationary and cylindrically symmetric vortex configurations for simple models representing an incompressible nonrelativistic superconductor in a...

Correlated adiabatic and isocurvature perturbations from double inflation (1999)

Langlois, David

It is shown that double inflation (two minimally coupled massive scalar fields) can produce correlated adiabatic and isocurvature primordial perturbations. Depending on the two relevant parameters of...

The Equation of State for Cool Relativistic Two-Constituent Superfluid Dynamics (1995)

Carter, Brandon, Langlois, David

The natural relativistic generalisation of Landau's two constituent superfluid theory can be formulated in terms of a Lagrangian $L$ that is given as a function of the entropy current 4-vector...