OCKHAM is a team of the LIP Computer Science laboratory (UMR5668) primarily working on Optimization, Signal Processing, Statistical Learning, Inverse Problems, Graphs, and Sparsity. It is hosted by the RHÔNE ALPES COMPLEX SYSTEMS INSTITUTE (IXXI).

Team presentation

The OCKHAM team develops machine learning techniques and signal processing algorithms with the main objective of endowing them with solid theoretical foundations, physical interpretability and resource-efficiency.

With a culture rooted at the interface of signal processing and machine learning, the team’s expertise leverages the notion of parsimony and its structured variants – noticeably via graphs. Indeed, sparsity plays a fundamental role to warrant the identifiability of decompositions in latent spaces, such as inverse problems in high dimensional signal processing, and it also allows the development of distributed algorithms to learn from highly compressed data representations with privacy guarantees. Sparsity on graphs also gives rise to  techniques for semi-supervised learning in difficult settings. A major challenge is to leverage these ideas to ensure not only resource-efficient methods, but also explainable decisions and interpretable learnt parameters.

Research themes

Axis 1: Sparsity for high-dimensional learning

Axis 2: Learning on graphs and learning of graph

Axis 3: Dynamic and frugal learning

International and industrial relations

  • EPFL, Switzerland
  • Univ. Genova, Italy
  • Univ. Louvain, Belgium
  • Univ. Florence & Insubria, Italy
  • Ohio State Univ., USA
  • Tech. Univ. Munich, Germany
  • Univ. of Edinburgh,UK
  • Univ. Basel, Switzerland


  • Hospices Civils de Lyon, France
  • Valeo AI, Paris, France
  • Meta AI (ex Facebook AI Research), Paris, France
  • LightOn SAS, Paris, France

OCKHAM is a joint research group between:

  • UDL
  • CNRS
  • Ecole normale supérieure de Lyon
  • Université Claude Bernard (Lyon 1)