Sébastien Fournier

Prof. Dr. Sébastien Fournier


Research Focus & Metrics

Academic Career Length

20Years (2007-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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14 November 2023 in Mathematics
Verified
Journal Article
Open access
PDF file
ACAdrian-Gabriel CHIFU
Adrian-Gabriel CHIFU
SFSébastien Fournier
Sébastien Fournier
Subjectivity is a key aspect of natural language understanding, especially in the context of user-generated text and conversational systems based on large language models. Natural language sentences often contain subjective elements, such as opinions and emotions, that make them more nuanced and complex. The level of detail at which the study of the text is performed determines the possible applications of sentiment analysis. The analysis can be done at the document or paragraph level, or, even more granularly, at the aspect level. Many researchers have studied this topic extensively. The field of aspect-based sentiment analysis has numerous data sets and models. In this work, we initiate the discussion around the definition of sentence difficulty in this context of aspect-based sentiment analysis. To assess and quantify the difficulty of the aspect-based sentiment analysis, we conduct an experiment using three data sets: “Laptops”, “Restaurants”, and “MTSC” (Multi-Target-dependent Sentiment Classification), along with 21 learning models from scikit-learn. We also use two textual representations, TF-IDF (Terms frequency-inverse document frequency) and BERT (Bidirectional Encoder Representations from Transformers), to analyze the difficulty faced by these models in performing aspect-based sentiment analysis. Additionally, we compare the models with a fine-tuned version of BERT on the three data sets. We identify the most challenging sentences using a combination of classifiers in order to better understand them. We propose two strategies for defining sentence difficulty. The first strategy is binary and considers sentences as difficult when the classifiers are unable to correctly assign the sentiment polarity. The second strategy uses a six-level difficulty scale based on how many of the top five best-performing classifiers can correctly identify sentiment polarity. These sentences with assigned difficulty classes are then used to create predictive models for early difficulty detection. The purpose of estimating the difficulty of aspect-based sentiment analysis is to enhance performance while minimizing resource usage.

28 October 2007
Verified
Book Chapter
Closed access
PDF file
Christophe ClaramuntChristophe Claramunt
Christophe Claramunt
TDT. Devogele
T. Devogele
SFSébastien Fournier
Sébastien Fournier
VNV. Noyon
V. Noyon
MPM. Petit
M. Petit
CRC. Ray
C. Ray

13 July 2025
Verified
Conference Paper
Open access
GBGrigor Bezirganyan
Grigor Bezirganyan
SSSana Sellami
Sana Sellami
Laure Berti-EquilleLaure Berti-Equille
Laure Berti-Equille
SFSébastien Fournier
Sébastien Fournier

16 March 2008
Verified
Conference Paper
Open access
PDF file
BEBernard Espinasse
Bernard Espinasse
SFSébastien Fournier
Sébastien Fournier
FFFred Freitas
Fred Freitas
Due to Web size and diversity of information, relevant information gathering on the Web is a very complex task. The main problem with most information retrieval approaches is neglecting the context of the pages, mainly because search engines are based on keyword indexing. Considering restricted domain, the policy of taking into account context may lead to more relevant information gathering in this paper, a specific cooperative information gathering approach based on the use of software agents and ontologies is proposed. To implement this approach, a generic software architecture, named AGATHE system, based on early prototype, the MASTER-Web system, permitting development of specific restricted-domain information gathering systems is presented in detail, with a focus on the extraction subsystem.

1 June 2013
Verified
Conference Paper
Closed access
MOMhammed Ali Oulhaci
Mhammed Ali Oulhaci
ETErwan Tranvouez
Erwan Tranvouez
BEBernard Espinasse
Bernard Espinasse
SFSébastien Fournier
Sébastien Fournier
Crisis management, serious games (SG) are more and more used for training. SG permit to reduce the cost of a such training and saving time, and in general provide a fun way to learn. In this paper we propose to bring together SG and Intelligent Tutoring Systems (ITS) in the context of the SIMFOR project, a SG for training in crisis management. We discuss the problems and needs of serious games and an overview of existing works. To enhance the learning aspect in SG, we propose the integration of different ITS functionalities to the SG. To perform this integration process, we propose an collaborative agent-based architecture. This architecture is presented in detail and illustrated on a realistic game scenario.

3 March 2022 in Mathematics
Verified
Journal Article
Open access
PDF file
Ismail BadacheIsmail Badache
Ismail Badache
ACAdrian-Gabriel CHIFU
Adrian-Gabriel CHIFU
SFSébastien Fournier
Sébastien Fournier
The analysis of user-generated content on the Internet has become increasingly popular for a wide variety of applications. One particular type of content is represented by the user reviews for programs, multimedia, products, and so on. Investigating the opinion contained by reviews may help in following the evolution of the reviewed items and thus in improving their quality. Detecting contradictory opinions in reviews is crucial when evaluating the quality of the respective resource. This article aims to estimate the contradiction intensity (strength) in the context of online courses (MOOC). This estimation was based on review ratings and on sentiment polarity in the comments, with respect to specific aspects, such as “lecturer”, “presentation”, etc. Between course sessions, users stop reviewing, and also, the course contents may evolve. Thus, the reviews are time dependent, and this is why they should be considered grouped by the course sessions. Having this in mind, the contribution of this paper is threefold: (a) defining the notion of subjective contradiction around specific aspects and then estimating its intensity based on sentiment polarity, review ratings, and temporality; (b) developing a dataset to evaluate the contradiction intensity measure, which was annotated based on a user study; (c) comparing our unsupervised method with supervised methods with automatic feature selection, over the dataset. The dataset collected from coursera.org is in English. It includes 2244 courses and 73,873 user-generated reviews of those courses.The results proved that the standard deviation of the ratings, the standard deviation of the polarities, and the number of reviews are suitable features for predicting the contradiction intensity classes. Among the supervised methods, the J48 decision trees algorithm yielded the best performance, compared to the naive Bayes model and the SVM model.