Gilles Dequen

Prof. Dr. Gilles Dequen

University of Picardie Jules Verne, Amiens, Hauts-de-France, France
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orcid

Research Focus & Metrics

Academic Career Length

26Years (2001-Present)

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

Representative Publications

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25 October 2021 in JMIR Human Factors
Verified
Journal Article
Open access
FCFederica Cilia
Federica Cilia
RCRomuald Carette
Romuald Carette
MEMahmoud Elbattah
Mahmoud Elbattah
GDGilles Dequen
Gilles Dequen
JGJean-Luc Guérin
Jean-Luc Guérin
BDBarbara Le Driant
Barbara Le Driant
Background: The early diagnosis of autism spectrum disorder (ASD) is highly desirable but remains a challenging task, which requires a set of cognitive tests and hours of clinical examinations. In addition, variations of such symptoms exist, which can make the identification of ASD even more difficult. Although diagnosis tests are largely developed by experts, they are still subject to human bias. In this respect, computer-assisted technologies can play a key role in supporting the screening process. Objective: This paper follows on the path of using eye tracking as an integrated part of screening assessment in ASD based on the characteristic elements of the eye gaze. This study adds to the mounting efforts in using eye tracking technology to support the process of ASD screening Methods: The proposed approach basically aims to integrate eye tracking with visualization and machine learning. A group of 59 school-aged participants took part in the study. The participants were invited to watch a set of age-appropriate photographs and videos related to social cognition. Initially, eye-tracking scanpaths were transformed into a visual representation as a set of images. Subsequently, a convolutional neural network was trained to perform the image classification task. Results: The experimental results demonstrated that the visual representation could simplify the diagnostic task and also attained high accuracy. Specifically, the convolutional neural network model could achieve a promising classification accuracy. This largely suggests that visualizations could successfully encode the information of gaze motion and its underlying dynamics. Further, we explored possible correlations between the autism severity and the dynamics of eye movement based on the maximal information coefficient. The findings primarily show that the combination of eye tracking, visualization, and machine learning have strong potential in developing an objective tool to assist in the screening of ASD. Conclusions: Broadly speaking, the approach we propose could be transferable to screening for other disorders, particularly neurodevelopmental disorders.

3 May 2021 in Journal of Imaging
Verified
Journal Article
Open access
PDF file
MEMahmoud Elbattah
Mahmoud Elbattah
CLColm Loughnane
Colm Loughnane
JGJean-Luc Guérin
Jean-Luc Guérin
RCRomuald Carette
Romuald Carette
FCFederica Cilia
Federica Cilia
GDGilles Dequen
Gilles Dequen
Over the past decade, deep learning has achieved unprecedented successes in a diversity of application domains, given large-scale datasets. However, particular domains, such as healthcare, inherently suffer from data paucity and imbalance. Moreover, datasets could be largely inaccessible due to privacy concerns, or lack of data-sharing incentives. Such challenges have attached significance to the application of generative modeling and data augmentation in that domain. In this context, this study explores a machine learning-based approach for generating synthetic eye-tracking data. We explore a novel application of variational autoencoders (VAEs) in this regard. More specifically, a VAE model is trained to generate an image-based representation of the eye-tracking output, so-called scanpaths. Overall, our results validate that the VAE model could generate a plausible output from a limited dataset. Finally, it is empirically demonstrated that such approach could be employed as a mechanism for data augmentation to improve the performance in classification tasks.

EAEmilien ARNAUD
Emilien ARNAUD
MEMahmoud Elbattah
Mahmoud Elbattah
CAChristine Ammirati
Christine Ammirati
GDGilles Dequen
Gilles Dequen
DGDaniel Aiham GHAZALI
Daniel Aiham GHAZALI
Background: During the coronavirus disease 2019 (COVID-19) pandemic, calculation of the number of emergency department (ED) beds required for patients with vs. without suspected COVID-19 represented a real public health problem. In France, Amiens Picardy University Hospital (APUH) developed an Artificial Intelligence (AI) project called “Prediction of the Patient Pathway in the Emergency Department” (3P-U) to predict patient outcomes. Materials: Using the 3P-U model, we performed a prospective, single-center study of patients attending APUH’s ED in 2020 and 2021. The objective was to determine the minimum and maximum numbers of beds required in real-time, according to the 3P-U model. Results A total of 105,457 patients were included. The area under the receiver operating characteristic curve (AUROC) for the 3P-U was 0.82 for all of the patients and 0.90 for the unambiguous cases. Specifically, 38,353 (36.4%) patients were flagged as “likely to be discharged”, 18,815 (17.8%) were flagged as “likely to be admitted”, and 48,297 (45.8%) patients could not be flagged. Based on the predicted minimum number of beds (for unambiguous cases only) and the maximum number of beds (all patients), the hospital management coordinated the conversion of wards into dedicated COVID-19 units. Discussion and conclusions: The 3P-U model’s AUROC is in the middle of range reported in the literature for similar classifiers. By considering the range of required bed numbers, the waste of resources (e.g., time and beds) could be reduced. The study concludes that the application of AI could help considerably improve the management of hospital resources during global pandemics, such as COVID-19.

23 February 2023 in npj Digital Medicine
Verified
Journal Article
Open access
PDF file
EAEmilien ARNAUD
Emilien ARNAUD
MEMahmoud Elbattah
Mahmoud Elbattah
CAChristine Ammirati
Christine Ammirati
GDGilles Dequen
Gilles Dequen
DGDaniel Aiham Ghazali
Daniel Aiham Ghazali
In the field of emergency medicine (EM), the use of decision support tools based on artificial intelligence has increased markedly in recent years. In some cases, data are omitted deliberately and thus constitute “data not purposely collected” (DNPC). This accepted information bias can be managed in various ways: dropping patients with missing data, imputing with the mean, or using automatic techniques (e.g., machine learning) to handle or impute the data. Here, we systematically reviewed the methods used to handle missing data in EM research. A systematic review was performed after searching PubMed with the query “(emergency medicine OR emergency service) AND (artificial intelligence OR machine learning)”. Seventy-two studies were included in the review. The trained models variously predicted diagnosis in 25 (35%) publications, mortality in 21 (29%) publications, and probability of admission in 21 (29%) publications. Eight publications (11%) predicted two outcomes. Only 15 (21%) publications described their missing data. DNPC constitute the “missing data” in EM machine learning studies. Although DNPC have been described more rigorously since 2020, the descriptions in the literature are not exhaustive, systematic or homogeneous. Imputation appears to be the best strategy but requires more time and computational resources. To increase the quality and the comparability of studies, we recommend inclusion of the TRIPOD checklist in each new publication, summarizing the machine learning process in an explicit methodological diagram, and always publishing the area under the receiver operating characteristics curve—even when it is not the primary outcome.

1 January 2004 in Lecture Notes in Computer Science
Verified
Book Chapter
Closed access
PDF file
GDGilles Dequen
Gilles Dequen
ODOlivier Dubois
Olivier Dubois

1 November 2012
Verified
Conference Paper
Closed access
FLFlorian Legendre
Florian Legendre
GDGilles Dequen
Gilles Dequen
MKMichaël Krajecki
Michaël Krajecki
The SATisfiability Problem is a core problem in mathematical logic and computing theory. In the last years, progresses have led it to be a great and competitive approach to practically solve a wide range of industrial and academic problems. Thus, the current SAT solving capacity allows the propositional formalism to be an interesting alternative to tackle cryptographic problems, and particularly introduced a new field called logical cryptanalysis [15]. This paper deals with an original application of the SAT problem to encode the well-known MD? and SHA? hash functions algorithm in a generic DIMACS formula. As cryptographic hash functions are central elements in modern cryptography we choose to validate our modelisation with a dedicated attack on the inversion of these functions. This attack behaves like a reverse-engineering process, thanks to a state of the art SAT solver achieving a weakening of the second preimage of MD? and SHA?. As a result, we present our modelisation and an improvement of the current limit of best practical attacks on step-reduced MD4, MD5 and SHA? inversions, respectively up to 39, 28 and 23 broken steps. Finally, a brief analyse of our results allows to give an idea about logical cryptanalysis and hash functions.