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L'équipe d'OpenEdition Lab a le plaisir de vous annoncer la soutenance de thèse en informatique de Hussam Hamdan (LSIS) :Sentiment Analysis in Social mediaElle aura lieu le mardi  1er décembre 2015 à 10h00à Aix-Marseille Université site St Charles, salle de séminaire de la FRIIAM, au 2è étage du bâtiment 7, chimie B Bloc 7 C1Directeur : Patrice BELLOT (LSIS) / Frédéric BECHET (LIF)Résumé : (la présentation orale sera en français)In this thesis, we address the problem of sentiment analysis. More specifically, we are interested in analyzing the sentiment expressed in social media texts such as tweets, restaurant, laptop, hotel reviews and the scholarly book reviews which are written by experts. We will focus on two main tasks: sentiment polarity detection in which we aim to determine the polarity (positive, negative or neutral) of a given text and the opinion target extraction in which we aim to extract the targets that the people tend to express their opinions towards them (e.g. for restaurant we may extract targets as food, pizza, service). Our main objective is constructing state-of-the-art systems which could do the two tasks. Therefore, we have proposed different supervised systems following three research directions: improving the system performance by term weighting, by enriching the document representation and by proposing a new model for sentiment classification.  For evaluation purpose, we have participated at an International Workshop on Semantic Evaluation (SemEval), we have chosen two tasks: Sentiment analysis in twitter in which we determine the polarity of a tweet and Aspect-Based sentiment analysis in which we extract the opinion targets in restaurant reviews, then we determine the polarity of each target, our systems has been among the first three best systems in all subtasks. We also applied our systems on a French book reviews corpus constructed by OpenEdition team for extracting the opinion targets and their polarities. Le jury sera composé de :Frédéric BECHETPatrice BELLOTJulien VELCIN - Université Lyon II, laboratoire ERICPatrick PAROUBEK - LIMSI (Paris Sud) CNRSBéatrice DAILLE, Université de Nantes, LINA CNRSJacques SAVOY, Université de Neuchâtel (Suisse)Invité : Marin DACOS, AMU-CNRS (directeur de l’Equipex OpenEdition)Plan :http://sciences.univ-amu.fr/sites/sciences.univ-amu.fr/files/plan_du_site_st_charles_02-12.pdf