Christos Chatzis

About Me

I am currently a PhD student at Simula Metropolitan Center for Digital Engineering (SimulaMet) studying matrix and tensor factorizations, specifically for temporal data.

My background is on computer science, specializing in data mining and scientific computing. I am especially intrigued by unsupervised machine learning due to its capacity to discover patterns that are not predefined and relationships we did not even know to look for.

Education

2022 – present Ph.D. in Engineering Science, Simula Metropolitan Center for Digital Engineering

2020 – 2022 M.Sc. in Computer Science, National and Kapodistrian University of Athens

2016 – 2020 B.Sc. in Informatics & Telecommunications, National and Kapodistrian University of Athens

Publications

Revealing Subject-Specific Temporal Patterns from Longitudinal Data

Christos Chatzis, David Horner, Rasmus Bro, Ann-Marie Malby Schoos, Morten Arendt Rasmussen, Evrim Acar
bioRxiv, 2026

Code

@article{Chatzis2026.02.01.703114,
  title = {Revealing Subject-Specific Temporal Patterns from Longitudinal Data},
  author = {Chatzis, Christos and Horner, David and Bro, Rasmus and Schoos, Ann-Marie Malby and Rasmussen, Morten Arendt and Acar, Evrim},
  journal = {bioRxiv},
  year = {2026},
  url = {https://www.biorxiv.org/content/early/2026/02/03/2026.02.01.703114},
  publisher = {Cold Spring Harbor Laboratory},
  doi = {10.64898/2026.02.01.703114},
  code = {https://github.com/cchatzis/Revealing-Subject-specific-Temporal-Patterns-from-Longitudinal-Data},
}

Extracting host-specific developmental signatures from longitudinal microbiome data

Balazs Erdos, Christos Chatzis, Jonathan Thorsen, Jakob Stokholm, Age K. Smilde, Morten A. Rasmussen, Evrim Acar
bioRxiv, 2025

Code

@article{erdos2025extracting,
  author = {Erdos, Balazs and Chatzis, Christos and Thorsen, Jonathan and Stokholm, Jakob and Smilde, Age K. and Rasmussen, Morten A. and Acar, Evrim},
  title = {Extracting host-specific developmental signatures from longitudinal microbiome data},
  id = {2025.11.22.689760},
  year = {2025},
  doi = {10.1101/2025.11.22.689760},
  publisher = {Cold Spring Harbor Laboratory},
  url = {https://www.biorxiv.org/content/early/2025/11/25/2025.11.22.689760},
  eprint = {https://www.biorxiv.org/content/early/2025/11/25/2025.11.22.689760.full.pdf},
  journal = {bioRxiv},
  code = {https://github.com/blzserdos/parafac2_microbiome},
}

dCMF: Learning Interpretable Evolving Patterns from Temporal Multiway Data

Christos Chatzis, Carla Schenker, Jérémy E. Cohen, Evrim Acar
2025 33rd European Signal Processing Conference (EUSIPCO), 2025

Code

@inproceedings{11226087,
  author = {Chatzis, Christos and Schenker, Carla and Cohen, Jérémy E. and Acar, Evrim},
  booktitle = {2025 33rd European Signal Processing Conference (EUSIPCO)},
  title = {dCMF: Learning Interpretable Evolving Patterns from Temporal Multiway Data},
  year = {2025},
  volume = {},
  number = {},
  pages = {2122-2126},
  doi = {10.23919/EUSIPCO63237.2025.11226087},
  code = {https://github.com/cchatzis/temp-dcmf-repo},
}

Talks

Contributed TalkUncovering evolving patterns in temporal data with tensor decompositions

June 2025 • TRICAP (Three-way Methods in Chemistry and Psychology) 2025 • Ålesund, Norway

Contributed TalkdCMF: Learning interpretable evolving patterns from temporal multiway data

May 2025 • Hidden structures in dynamical systems, optimization, and machine learning, Gran Sasso Science Institute • L'Aquila, Italy

Abstract Website

Contributed TalkA Time-aware tensor decomposition for concept evolution

March 2024 • 94th Annual meeting of the International Association of Applied Mathematics and Mechanics (GAMM 2024) • Magdeburg, Germany

Academic Service

Reviewing

ICML 2026 workshop: Connecting Low-rank Representations in AI (CoLorAI'26)

Teaching

Spring 2026Data Mining at Scale: Algorithms and Systems (Lecturer), OsloMet

Spring 2021Data mining techniques (Teaching assistant), National and Kapodistrian University of Athens

Winter 2021Numerical analysis (Teaching assistant), National and Kapodistrian University of Athens

Winter 2020Numerical analysis (Teaching assistant), National and Kapodistrian University of Athens

News

February 2026A new preprint is available Revealing Subject-Specific Temporal Patterns from Longitudinal Data. 📄 Paper

December 2025I will be lecturing ACIT4530: Data Mining at Scale: Algorithms and Systems at OsloMet this Spring 2026 semester. Excited to get started!

November 2025A new preprint is available Extracting host-specific developmental signatures from longitudinal microbiome data. 📄 Paper

September 2025Our work tPARAFAC2: Tracking evolving patterns in (incomplete) temporal data is now published! 📄 Paper

September 2025Our work dCMF: Learning interpretable evolving patterns from temporal multiway data is now published! 📄 Paper