Scientific seminars

15/02/2024

Speaker: Sasha Piccione, PhD Student, Venice (Italy) at the Ca' Foscari University of Venice and IMT Atlantique (Brest). 

Title: I'm politer than you just because I think I owe you

Abstract: The aim of this research is to investigate the factors that influence the tone (measured as arousal and valence) used by Wikipedians when discussing on Talk Pages. The research focuses on isolating contextual characteristics from demographic characteristics, drawing on literature regarding social cues and mimicry. The ultimate objective is to determine the extent to which contextual factors influence the tone expressed in written comments.

Keywords: Online Open communities, stigmergy, sentiment analysis

08/02/2024

Speaker: Ebtissem Sassi, enseignante-chercheure, ENSIBS (Lorient)

Abstract: This presentation looks at work in progress around the themes of supply chain optimization and decision support, with a focus on digital twins: designing and deploying a digital twin of the short food supply chain.

18/01/2024

Speaker: Florian RASCOUSSIER, PhD student, DECIDE, Lab-STICC

Title: Predicting SSH keys in OpenSSH Memory dumps

Abstract: This work is the result of a final year research project (Masterarbeit) aimed at advancing the field of cybersecurity through machine learning. The contribution lies in the development of algorithms and the training of various learning models to predict the locations of SSH keys in OpenSSH memory heap dumps.

Keywords: graphs, SSH, key, embedding, machine learning, graph convolution network, binary classification 

11/01/2024

Speaker: Nicolas Jullien, professor, laboratoire LEGO

Title: IA in digital comm(unitie)s. A socio-economics approach.  

Abstract: Algorithmic management is blamed for its errors which would have discriminatory effects. Does Wikipedia do better in that matter? Through the analysis of the management of the most important bot fighting vandalism for the Fr-Wikipedia, we show that 1) over-standardization and discrepancies are hardly avoidable on the long run; 2) it is an issue for any platform, as it decreases its creativity and thus its attractiveness; 3) counterbalancing this is not one of technical limitations, but of socio-technical arrangements, on developing the human control and analysis of algorithmic decisions 

15/11/2023

Speaker: Shoko Wakamiya, Associate Professor at Nara Institute of Science and Technology, Social Computing lab Japan

Title: Health-related Social Media Data Analysis and Applications

Abstract: With the development of social media and smartphones, various crowd-based data are available, and some are linked to locations. In this talk, I will present some studies using web and social media data, which would contribute to health promotion and well-being. Also, I'll talk about the challenges in using these data and ongoing projects to address them.

Keywords: text data processing, social media / network analysis, social computing, health, ...

09/11/2023

Speaker: Antti Knutas, associate professor, LUT University (Finland)

Title: “Software Engineering in Civic Technology: Introduction to the Field, Research Trajectory, and Lessons Learned” 

Bio: Antti Knutas is an associate professor at LUT University Department of Software Engineering and has spend one month at IMT Atlantique as a visiting researcher. His current research area is how grassroots civic tech communities design, create, and share software (see his webpage for details https://anttiknutas.net). 

20/10/2023

Speaker: Baptiste Alglave, associate professor, équipe DECIDE, Lab-STICC.

Title: "Integrating massive and heterogeneous spatio-temporal data to infer spatial processes. Marine ecology as field of application."

28/09/2023

Speaker: Gábor Bella, associate professor, équipe DECIDE, Lab-STICC

Title: "Semantic interoperability of healthcare data"

05/07/2023

Speaker: Ba Huy Pham, PhD Student, équipe MATRIX, Lab-STICC, ONERA

Title: Tracking with an antenna array for radar observation "around the corner"

26/05/2023

Speaker: Alexandre Reiffers-Masson, maître de conférences, équipe MATHS & NET, LAB-STICC 

Title: Stochastic Processes and Stochastic Algorithms for Distributed Systems 

Abstract: In this talk, I will present my recent works on distributed systems. First, I will focus on Directed Acyclic Graphs (DAG)-based distributed ledgers. In distributed ledger technologies (DLTs) with a directed acyclic graph (DAG) data structure, a block-issuing node can decide where to append new blocks and, consequently, how the DAG grows. This DAG data structure is typically decomposed into two pools of blocks, dependent on whether another block already references them. The unreferenced blocks are called the tips. Due to network delay, nodes can perceive the set of tips differently, giving rise to local tip pools. In this series of works, we have proposed new mathematical models to capture the evolution of the number of tips under the presence of heterogeneous delay in the peer-to-peer network. I will show the different theoretical properties obtained, such as stability, ergodicity, and upper bound on the average number of tips.  

Then, in the second part of the talk, I will consider the measurement model Y = AX where X and, hence, Y are random variables and A is an a priori known tall matrix. At each time instance, a sample of one of Y's coordinates is available, and the goal is to estimate E[X] via these samples. However, the challenge is that a small but unknown subset of Y's coordinates are controlled by adversaries with infinite power: they can return any real number each time they are queried for a sample. For such an adversarial setting, we propose the first asynchronous online algorithm that converges to E[X] almost surely. We prove this result using a novel differential inclusion based two-timescale analysis. Our algorithm can be used in decentralized scenarios, such as decentralized byzantine-robust gradient estimation. 

20/04/2023

Speaker : Esteban Bautista, postdoc, DECIDE, Lab-STICC

Title: A frequency-structure decomposition for link streams

Abstract: A link stream is a set of triplets (t, u, v) modeling interactions over time, such as person u calling v at time t, or bank account u transferring money to v at time t. Effectively analyzing link streams is key for numerous applications. In practice, they are commonly studied as collections of graphs or time series, yet adapting the data for signal and graph methods often leads to unsatisfactory tradeoffs. Thus calling for methods dedicated for link streams. In this work, our goal is to develop a decomposition for link streams: breaking down a complex link stream into simpler ones that are easier to study. For this we develop a novel structural decomposition that interacts well with time-series decompositions. We show that their combination allows to decompose a link stream into simple structures oscillating at a specific frequency. Moreover, we show that this permits to easily introduce filters for link streams which can be useful in various settings.

02/03/2023

Speaker: Erwan Alincourt, Lieutenant de vaisseau dans la marine nationale, doctorant, DECIDE, Lab-STICC

Title: Mapping, anomaly detection and post-detection response on industrial systems: application to military and civilian ships

22/12/2022

Speaker: Patrick Meyer, professeur, DECIDE, Lab-STICC

Title: "A genetic algorithm for learning the parameters of an SRMP preference model". 

Abstract: In the domain of Multiple Criteria Decision Aiding, decision makers are faced with problems involving multiple conflicting criteria. Preference models are used to reach a decision in such situations. To tune the parameters of those models, preference elicitation algorithms are used, generally using so-called holistic judgments as inputs. In this work, we focus on a specific preference model called ranking based on multiple reference profiles. In the literature, mixed-integer linear programming and constraint programming techniques have already been proposed to tune the model parameters. However these approaches have difficulties to handle realistic large scale problems. We propose here an evolutionary metaheuristic in order to address this issue, which we test using extensive numerical experiments in order to highlight its performance and limits. We show that the proposed metaheuristic has the capacity to reproduce learning inputs very well, while having an important generalization power.

12/05/2022

Speaker: Quentin Perrachon, doctorant, DECIDE, Lab-STICC

Presented paper: Quentin Perrachon, Alexandru-Liviu Olteanu, Marc Sevaux. PPC pour un problème d'ordonnancement industriel : Multi-Resource Flexible Job Shop. 23ème congrès annuel de la Société Française de Recherche Opérationnelle et d'Aide à la Décision, INSA Lyon, Feb 2022, Villeurbanne - Lyon, France. ⟨hal-03595382⟩

Abstract: Hérakles develops and distributes ERP-GPAO throughout France. Its customers are mainly very small, small and medium-sized industries. Hérakles aims to offer and supply intelligent scheduling solutions to its customers. Within the framework of a CIFRE thesis in collaboration between Hérakles and the DECIDE team of the Lab-STICC laboratory, we present an initial solution method for industrial workshop scheduling problems corresponding to a majority of Hérakles' customers.

24/03/2022

Speaker: Antoine Mallégol, PhD Student, DECIDE, Lab-STICC

Title: "Multi-objective optimization of multi-energy systems: mathematical model and study of different linearization methods" 

Presented paper: https://hal.archives-ouvertes.fr/hal-03595359

16/09/2021

Speaker: Yannis Haralambous, Professor, DECIDE, Lab-STICC

Presented paper: Haralambous, Yannis, and Tian Tian. "Tailoring a controlled language out of a corpus of maintenance reports." Proceedings of the Seventh International Workshop on Controlled Natural Language (CNL 2020/21). 2021.

Abstract: We introduce a method for tailoring a controlled language out of a specialized language corpus, as well as for training the user to ensure a smooth transition between the specialized and the controlled language. Our method is based on the selection of maximal coverage syntax rules. The number of rules chosen is a naturalness vs. formality parameter of the controlled language. We introduce a training tool that displays segmentation into left-to-right maximal parsed sentences and allows utterance modification by the user until a complete parse is achieved. We have applied our method to a French corpus of maintenance reports of boilers in a thermal power station and provide coverage and segmentation results.