Portrait of Guillaume Rabusseau

Guillaume Rabusseau

Core Academic Member
Canada CIFAR AI Chair
Assistant Professor, Université de Montréal, Department of Computer Science and Operations Research
Research Topics
Deep Learning
Graph Neural Networks
Learning on Graphs
Machine Learning Theory
Probabilistic Models
Quantum Information Theory
Recommender Systems
Recurrent Neural Networks
Tensor Factorization

Biography

I have been an assistant professor at Mila – Quebec Artificial Intelligence Institute and in the Department of Computer Science and Operations Research (DIRO) at Université de Montréal (UdeM) since September 2018. I was awarded a Canada CIFAR AI Chair in March 2019. Before joining UdeM, I was a postdoctoral research fellow in the Reasoning and Learning Lab at McGill University, where I worked with Prakash Panangaden, Joelle Pineau and Doina Precup.

I obtained my PhD in 2016 from Aix-Marseille University (AMU) in France, where I worked in the Qarma team (Machine Learning and Multimedia) under the supervision of François Denis and Hachem Kadri. I also obtained my MSc in fundamental computer science and my BSc in computer science from AMU. I am interested in tensor methods for machine learning and in designing learning algorithms for structured data by leveraging linear and multilinear algebra (e.g., spectral methods).

Current Students

Postdoctorate - McGill University
Co-supervisor :
Postdoctorate - Université de Montréal
Collaborating Alumni - Université de Montréal
PhD - Université de Montréal
Co-supervisor :
Collaborating researcher - McGill University
Principal supervisor :
PhD - Université de Montréal
Postdoctorate - McGill University
Co-supervisor :
Research Intern - Polytechnique Montréal
Collaborating researcher - INRIA
Master's Research - Université de Montréal
Collaborating researcher - Université de Montréal
Co-supervisor :
PhD - Université de Montréal
Research Intern - Université de Montréal

Publications

Laplacian Change Point Detection for Single and Multi-view Dynamic Graphs
Dynamic graphs are rich data structures that are used to model complex relationships between entities over time. In particular, anomaly dete… (see more)ction in temporal graphs is crucial for many real world applications such as intrusion identification in network systems, detection of ecosystem disturbances and detection of epidemic outbreaks. In this paper, we focus on change point detection in dynamic graphs and address three main challenges associated with this problem: i). how to compare graph snapshots across time, ii). how to capture temporal dependencies, and iii). how to combine different views of a temporal graph. To solve the above challenges, we first propose Laplacian Anomaly Detection (LAD) which uses the spectrum of graph Laplacian as the low dimensional embedding of the graph structure at each snapshot. LAD explicitly models short term and long term dependencies by applying two sliding windows. Next, we propose MultiLAD, a simple and effective generalization of LAD to multi-view graphs. MultiLAD provides the first change point detection method for multi-view dynamic graphs. It aggregates the singular values of the normalized graph Laplacian from different views through the scalar power mean operation. Through extensive synthetic experiments, we show that i). LAD and MultiLAD are accurate and outperforms state-of-the-art baselines and their multi-view extensions by a large margin, ii). MultiLAD's advantage over contenders significantly increases when additional views are available, and iii). MultiLAD is highly robust to noise from individual views. In five real world dynamic graphs, we demonstrate that LAD and MultiLAD identify significant events as top anomalies such as the implementation of government COVID-19 interventions which impacted the population mobility in multi-view traffic networks.
Generative Learning of Continuous Data by Tensor Networks
Alex Meiburg
Jian Hua Chen
Raphaelle Tihon
Alejandro Perdomo-ortiz
Temporal Graph Benchmark for Machine Learning on Temporal Graphs
Matthias Fey
Weihua Hu
Emanuele Rossi
Jure Leskovec
Michael M. Bronstein
We present the Temporal Graph Benchmark (TGB), a collection of challenging and diverse benchmark datasets for realistic, reproducible, and r… (see more)obust evaluation of machine learning models on temporal graphs. TGB datasets are of large scale, spanning years in duration, incorporate both node and edge-level prediction tasks and cover a diverse set of domains including social, trade, transaction, and transportation networks. For both tasks, we design evaluation protocols based on realistic use-cases. We extensively benchmark each dataset and find that the performance of common models can vary drastically across datasets. In addition, on dynamic node property prediction tasks, we show that simple methods often achieve superior performance compared to existing temporal graph models. We believe that these findings open up opportunities for future research on temporal graphs. Finally, TGB provides an automated machine learning pipeline for reproducible and accessible temporal graph research, including data loading, experiment setup and performance evaluation. TGB will be maintained and updated on a regular basis and welcomes community feedback. TGB datasets, data loaders, example codes, evaluation setup, and leaderboards are publicly available at https://tgb.complexdatalab.com/.
Towards Foundational Models for Molecular Learning on Large-Scale Multi-Task Datasets (Ultra Large Dataset)
Joao Alex Cunha
Zhiyi Li
Samuel Maddrell-Mander
Callum McLean
Luis T. Díaz Müller
Jama Hussein Mohamud
Michael Craig
Cristian Gabellini
Christopher G. Morris
Hadrien Mary
Błażej Banaszewski
Chad Martin
Dominic Masters
Preface
François Coste
Faissal Ouardi
ROSA: Random Orthogonal Subspace Adaptation
Fast and Attributed Change Detection on Dynamic Graphs with Density of States
Benchmarking State-Merging Algorithms for Learning Regular Languages.
Adil Soubki
Jeffrey Heinz
François Coste
Faissal Ouardi
Explaining Graph Neural Networks Using Interpretable Local Surrogates
Formal and Empirical Studies of Counting Behaviour in ReLU RNNs.
Nadine El-Naggar
Andrew Ryzhikov
Laure Daviaud
Pranava Madhyastha
Tillman Weyde
François Coste
Faissal Ouardi
Identification of Substitutable Context-Free Languages over Infinite Alphabets from Positive Data
Yutaro Numaya
Diptarama Hendrian
Ryo Yoshinaka
Ayumi Shinohara
François Coste
Faissal Ouardi
This paper is concerned with the identification in the limit from positive data of sub-stitutable context-free languages cfl s) over infinit… (see more)e alphabets. Clark and Eyraud (2007) showed that substitutable cfl s over finite alphabets are learnable in this learning paradigm. We show that substitutable cfl s generated by grammars whose production rules may have predicates that represent sets of potentially infinitely many terminal symbols in a compact manner are learnable if the terminal symbol sets represented by those predicates are learnable, under a certain condition. This can be seen as a result parallel to Argyros and D’Antoni’s work (2018) that amplifies the query learnability of predicate classes to that of symbolic automata classes. Our result is the first that shows such amplification is possible for identifying some cfl s in the limit from positive data.
Learning Syntactic Monoids from Samples by extending known Algorithms for learning State Machines
Simon Dieck
Sicco Verwer
François Coste
Faissal Ouardi
For the inference of regular languages, most current methods learn a version of deterministic finite automata. Syntactic monoids are an alte… (see more)rnative representation of regular languages, which have some advantages over automata. For example, traces can be parsed starting from any index and the star-freeness of the language they represent can be checked in polynomial time. But, to date, there existed no passive learning algorithm for syntactic monoids. In this paper, we prove that known state-merging algorithms for learning deterministic finite automata can be instrumented to learn syntactic monoids instead, by using as the input a special structure proposed in this paper: the interfix-graph. Further, we introduce a method to encode frequencies on the interfix-graph, such that models can also be learned from only positive traces. We implemented this structure and performed experiments with both traditional data and data containing only positive traces. As such this work answers basic theoretical and experimental questions regarding a novel passive learning algorithm for syntactic monoids.