Personal Information

Name
Lylian SIFFRE

Email
lylian@siff.re

Github
https://github.com/xonturis

LinkedIn
https://www.linkedin.com/in/lylian-siffre

ORCID
https://orcid.org/0009-0004-5743-9337

Education

PhD in Computer Science (ongoing)
IMT Atlantique (Nov. 2024 - Nov. 2027)
Supervisor: Thomas Ledoux
Summary: Since the topic evolves during the thesis, for now, refer to publications/preprints/posters.

Engineer’s Degree in Computer Science
Polytech Nantes, Université de Nantes (Sept. 2021 - Sept. 2024)
Topics: Advanced database management, data quality, data analysis, AI algorithms.

Associate Degree in Computer Science
IUT de Nantes, Université de Nantes (Sept. 2019 - June 2021)
Topics: Web development (HTML/CSS/JS & PHP), technical solution design (UML), project management, databases, Java, Python, C, statistics, linear algebra.

High School Diploma – STI2D (SIN specialization)
Lycée Gustave Eiffel de Bordeaux (June 2019)
With Highest Honors (Mention Très Bien).

Professional Experience

PhD Student
Kapela, Nantes (Nov. 2024 - Nov. 2027)

• Study of Local-First Software’s impact on green software design
• Scientific outreach to industry professionals
• Research valorization with industrial partners

Research Engineer (Apprenticeship)
Impakt, Nantes (Sept. 2021 – Sept. 2024)

• Authored and published a research paper at a European conference (see Publications).
• Developed energy measurement software (see Publications).
• Designed and compared efficiency between eco-designed and non-eco-designed prototypes.

Backend Developer Intern
ValueChecker, Stockholm, Sweden (June 2023 - Aug. 2023)

• REST standardization of an HTTP API.
• Identified and corrected non-compliant issues.
• Communicated changes to the team.
• Wrote documentation to maintain REST compliance.
• SQL query optimization.
• API testing and CI/CD integration.
• Participated in recruitment processes.

Computer Developer Intern
LS2N, Nantes (Apr. 2021 – June 2021)

• Data warehouse management.
• SQL database extraction.
• Data quality reporting.
• Team workflow methodology implementation.

Technical Skills

• Data Analysis: Numpy, Pandas, Matplotlib, scikit-learn, Tableau, Excel
• Design: UML, Entity-Relationship
• Programming: Python, Java, Go, JavaScript, PHP, C, C++
• Web Frameworks: React, Vue
• Languages: Native French, English (TOEIC 965/990, 2022)
• Documentation: LaTeX, Word

Research

My research interest is currently about the energy consumption of Local-First Software (LoFi). Later, I will focus on building a methodology for shifting SaaS towards LoFi. Feel free to contact me if you think we could collaborate!

Publications

Lylian Siffre, Thomas Ledoux, Renaud Pawlak, John Guery. Local Computing vs. Cloud Computing: An Empirical Study of Energy Consumption. IEEE/ACM 18th International Conference on Utility and Cloud Computing, Dec 2025, Nantes, France. pp.1-10. ⟨hal-05324506⟩

Lylian Siffre, Thomas Ledoux, Renaud Pawlak, John Guery. Local-First Software for Green IT. ICT4S 2025 - International Conference on Information and Communications Technology for Sustainability, Jun 2025, Dublin, Ireland. pp.1-10. ⟨hal-05037019⟩

Lylian Siffre, Gabriel Breuil, Adel Noureddine, Renaud Pawlak. Demeter: An Architecture for Long-Term Monitoring of Software Power Consumption. 17th European Conference on Software Architecture, Sep 2023, Istanbul, Turkey. ⟨hal-04231337⟩

Keynotes

“Local-First Software : L’informatique frugale, résiliente et centrée sur l’humain au-delà du tout-Cloud” (in French) @ Verdinum : L’IA frugale dans ses différentes dimensions, November 6th 2025. More details…

Posters

Lylian Siffre. 2025. Local-First Software for Green IT. Greendays 2025, Rennes. https://siff.re/public/Position_Paper_Poster.pdf

Reviews

• Reviewer for UCC'25 Poster Session
• Sub Reviewer for IEEE CLOUD 2025

Teaching

• Introduction to programming, Programming project, IMT Atlantique (1st-year Engineering students, 2025)
• Introduction to Research, IMT Atlantique (3rd-year Engineering students, 2025). With Hélène Coullon
• Object-Oriented Programming, Databases & Networks Project, IMT Atlantique (1st-year Engineering students, 2025)
• Object-Oriented Programming, IMT Atlantique (1st-year Engineering students, 2025)

Mentorship

• Supervised a group of three 3rd-year engineering students at IMT Atlantique for a Frontend/Backend project. (October - ongoing)
  Output: ongoing
• Supervised a 2nd-year engineering intern at Stack, LS2N (Jan–Feb 2025).
  Output: https://gitlab.inria.fr/lsiffre/service-energy-monitor

Organization

• Volunteer Student at UCC'2025
• Stack Team Seminar 2025:
  • Program
  • Session Chair

Other Activities

Board Member
Communication committee member for a French nonprofit (1901 law) (2024 – ongoing).

Vice President & Treasurer
Financial management for a nonprofit (2020 – 2021).

Minecraft Game Server Project Lead
(Agile team management, developer recruitment, inter-team coordination, Java development, database/server administration) (2018 - 2021).

IUT Projects:

• Logic gate game in HTML/CSS (no JS): 🌐
• Go messaging program: 🌐
• Java game “Le neutron”: 🌐
• PHP 2048: 🌐