Efficient Combination of Confidence Measures for Machine Translation

International audienceWe 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 corpora containing realistic errors. Errors introduced into reference translation simulate classical machine translation errors (word deletion and word substitution), and are supervised by Wordnet. Second, we use SVM to combine original and classical confidence measures both at word- and sentence-level. We show that the obtained combination outperforms by 14% (absolute) our best single word-level confidence measure, and that combination of sentence-level confidence measures produces meaningful scores

"This sentence is wrong." Detecting errors in machine-translated sentences.

International audienceMachine translation systems are not reliable enough to be used ''as is'': except for the most simple tasks, they can only be used to grasp the general meaning of a text or assist human translators. The purpose of confidence measures is to detect erroneous words or sentences produced by a machine translation system. In this article after reviewing the mathematical foundations of confidence estimation we propose a comparison of several state-of-the-art confidence measures, predictive parameters and classifiers. We also propose two original confidence measures based on Mutual Information and a method for automatically generating data for training and testing classifiers. We applied these techniques to data from WMT campaign 2008 and found that the best confidence measures yielded an Equal Error Rate of 36.3% at word level and 34.2% at sentence level, but combining different measures reduced these rates to respectively 35.0\% and 29.0\%. We also present the results of an experiment aimed at determining how helpful confidence measures are in a post edition task. Preliminary results suggest that our system is not yet ready to efficiently help post editors, but we now have a software and protocol we can apply to further experiments, and user feedback has indicated aspects which must be improved in order to increase the level of helpfulness of confidence measures

Broadcast news speech-to-text translation experiments

International audienceWe present S2TT, an integrated speech-to-text translation system based on POCKETSPHINX and MOSES. It is compared to different baselines based on ANTS --- the broadcast news transcription system developed at LORIA's Speech group, MOSES and Google's translation tools. A small corpus of reference transcriptions of broadcast news from the evaluation campaign ESTER2 was translated by human experts for evaluation. The Word Error Rate (WER) of the recognition stage of both systems are evaluated, and BLEU is used to score the translations. Furthermore, the reference transcriptions are automatically translated using MOSES and GOOGLE in order to evaluate the impact of recognition errors on translation quality

New Confidence Measures for Statistical Machine Translation

International audienceA 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 decide whether the most probable sequence of words provided by the machine translation system is correct or not. In the following we describe several original word-level confidence measures for machine translation, based on mutual information, n-gram language model and lexical features language model. We evaluate how well they perform individually or together, and show that using a combination of confidence measures based on mutual information yields a classification error rate as low as 25.1\% with an F-measure of 0.708

Word- and sentence-level confidence measures for machine translation

International audienceA 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 correctness. In this article we describe several word- and sentence-level confidence measures relying on different features: mutual information between words, n-gram and backward n-gram language models, and linguistic features. We also try different combination of these measures. Their accuracy is evaluated on a classification task. We achieve 17% error-rate (0.84 f-measure) on word-level and 31% error-rate (0.71 f-measure) on sentence-level

On the use of confidence measures in machine translation : evaluation, post edition and application to speech translation

Cette thèse de doctorat aborde les problématiques de l'estimation de confiance pour la traduction automatique, et de la traduction automatique statistique de la parole spontanée à grand vocabulaire. J'y propose une formalisation du problème d'estimation de confiance, et aborde expérimentalement le problème sous le paradigme de la classification et régression multivariée. Je propose une évaluation des performances des différentes méthodes évoquées, présente les résultats obtenus lors d'une campagne d'évaluation internationale et propose une application à la post-édition par des experts de documents traduits automatiquement. J'aborde ensuite le problème de la traduction automatique de la parole. Après avoir passé en revue les spécificités du medium oral et les défis particuliers qu'il soulève, je propose des méthodes originales pour y répondre, utilisant notamment les réseaux de confusion phonétiques, les mesures de confiances et des techniques de segmentation de la parole. Je montre finalement que le prototype propose rivalise avec des systèmes état de l'art à la conception plus classiqueIn this thesis I shall deal with the issues of confidence estimation for machine translation and statistical machine translation of large vocabulary spontaneous speech translation. I shall first formalize the problem of confidence estimation. I present experiments under the paradigm of multivariate classification and regression. I review the performances yielded by different techniques, present the results obtained during the WMT2012 internation evaluation campaign and give the details of an application to post edition of automatically translated documents. I then deal with the issue of speech translation. After going into the details of what makes it a very specific and particularly challenging problem, I present original methods to partially solve it, by using phonetic confusion networks, confidence estimation techniques and speech segmentation. I show that the prototype I developped yields performances comparable to state-of-the-art of more standard desig

De l'utilisation de mesures de confiance en traduction automatique : évaluation, post-édition et application à la traduction de la parole

In this thesis I shall deal with the issues of confidence estimation for machine translation and statistical machine translation of large vocabulary spontaneous speech translation. I shall first formalize the problem of confidence estimation. I present experiments under the paradigm of multivariate classification and regression. I review the performances yielded by different techniques, present the results obtained during the WMT2012 internation evaluation campaign and give the details of an application to post edition of automatically translated documents. I then deal with the issue of speech translation. After going into the details of what makes it a very specific and particularly challenging problem, I present original methods to partially solve it, by using phonetic confusion networks, confidence estimation techniques and speech segmentation. I show that the prototype I developped yields performances comparable to state-of-the-art of more standard design.Cette thèse de doctorat aborde les problématiques de l'estimation de confiance pour la traduction automatique, et de la traduction automatique statistique de la parole spontanée à grand vocabulaire. J'y propose une formalisation du problème d'estimation de confiance, et aborde expérimentalement le problème sous le paradigme de la classification et régression multivariée. Je propose une évaluation des performances des différentes méthodes évoquées, présente les résultats obtenus lors d'une campagne d'évaluation internationale et propose une application à la post-édition par des experts de documents traduits automatiquement. J'aborde ensuite le problème de la traduction automatique de la parole. Après avoir passé en revue les spécificités du medium oral et les défis particuliers qu'il soulève, je propose des méthodes originales pour y répondre, utilisant notamment les réseaux de confusion phonétiques, les mesures de confiances et des techniques de segmentation de la parole. Je montre finalement que le prototype propose rivalise avec des systèmes état de l'art à la conception plus classique

LORIA System for the WMT12 Quality Estimation Shared Task

International audienceIn this paper we present the system we submitted to the WMT12 shared task on Quality Estimation. Each translated sentence is given a score between 1 and 5. The score is obtained using several numerical or boolean features calculated according to the source and target sentences. We perform a linear regression of the feature space against scores in the range [1:5]. To this end, we use a SupportVectorMachine. We experimentwith two kernels: linear and radial basis function. In our submission we use the features from the shared task baseline system and our own features. This leads to 66 features. To deal with this large number of features, we propose an in-house feature selection algorithm. Our results show that a lot of information is already present in baseline features, and that our feature selection algorithm discards features which are linearly correlated

De l'utilisation de mesures de confiance en traduction automatique (évaluation, post-édition et application à la traduction de la parole)

Cette thèse de doctorat aborde les problématiques de l'estimation de confiance pour la traduction automatique, et de la traduction automatique statistique de la parole spontanée à grand vocabulaire. J'y propose une formalisation du problème d'estimation de confiance, et aborde expérimentalement le problème sous le paradigme de la classification et régression multivariée. Je propose une évaluation des performances des différentes méthodes évoquées, présente les résultats obtenus lors d'une campagne d'évaluation internationale et propose une application à la post-édition par des experts de documents traduits automatiquement. J'aborde ensuite le problème de la traduction automatique de la parole. Après avoir passé en revue les spécificités du medium oral et les défis particuliers qu'il soulève, je propose des méthodes originales pour y répondre, utilisant notamment les réseaux de confusion phonétiques, les mesures de confiances et des techniques de segmentation de la parole. Je montre finalement que le prototype propose rivalise avec des systèmes état de l'art à la conception plus classiqueIn this thesis I shall deal with the issues of confidence estimation for machine translation and statistical machine translation of large vocabulary spontaneous speech translation. I shall first formalize the problem of confidence estimation. I present experiments under the paradigm of multivariate classification and regression. I review the performances yielded by different techniques, present the results obtained during the WMT2012 internation evaluation campaign and give the details of an application to post edition of automatically translated documents. I then deal with the issue of speech translation. After going into the details of what makes it a very specific and particularly challenging problem, I present original methods to partially solve it, by using phonetic confusion networks, confidence estimation techniques and speech segmentation. I show that the prototype I developped yields performances comparable to state-of-the-art of more standard designMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF

De l'utilisation de mesures de confiance en traduction automatique (évaluation, post-édition et application à la traduction de la parole)

Cette thèse de doctorat aborde les problématiques de l'estimation de confiance pour la traduction automatique, et de la traduction automatique statistique de la parole spontanée à grand vocabulaire. J'y propose une formalisation du problème d'estimation de confiance, et aborde expérimentalement le problème sous le paradigme de la classification et régression multivariée. Je propose une évaluation des performances des différentes méthodes évoquées, présente les résultats obtenus lors d'une campagne d'évaluation internationale et propose une application à la post-édition par des experts de documents traduits automatiquement. J'aborde ensuite le problème de la traduction automatique de la parole. Après avoir passé en revue les spécificités du medium oral et les défis particuliers qu'il soulève, je propose des méthodes originales pour y répondre, utilisant notamment les réseaux de confusion phonétiques, les mesures de confiances et des techniques de segmentation de la parole. Je montre finalement que le prototype propose rivalise avec des systèmes état de l'art à la conception plus classiqueIn this thesis I shall deal with the issues of confidence estimation for machine translation and statistical machine translation of large vocabulary spontaneous speech translation. I shall first formalize the problem of confidence estimation. I present experiments under the paradigm of multivariate classification and regression. I review the performances yielded by different techniques, present the results obtained during the WMT2012 internation evaluation campaign and give the details of an application to post edition of automatically translated documents. I then deal with the issue of speech translation. After going into the details of what makes it a very specific and particularly challenging problem, I present original methods to partially solve it, by using phonetic confusion networks, confidence estimation techniques and speech segmentation. I show that the prototype I developped yields performances comparable to state-of-the-art of more standard designMETZ-SCD (574632105) / SudocNANCY1-Bib. numérique (543959902) / SudocNANCY2-Bibliotheque electronique (543959901) / SudocNANCY-INPL-Bib. électronique (545479901) / SudocSudocFranceF