Samira Ebrahimi Kahou

Biography

I am an Assistant Professor at the Schulich School of Engineering's Department of Electrical and Software Engineering at the University of Calgary. I am also an adjunct professor at the Department of Computer Engineering and Information Technology of ÉTS and an adjunct professor at the Computer School of McGill. Before joining ÉTS, I was a postdoctoral fellow working with Professor Doina Precup at McGill/Mila. Before my postdoc, I was a researcher at Microsoft Research Montréal.

I received my Ph.D. from Polytechnique Montréal/Mila in 2016 under the supervision of Professor Chris Pal. During my Ph.D. studies, I worked on computer vision and deep learning applied to emotion recognition, object tracking and knowledge distillation.

Current Students

Aamer Abdul Rahman

Master's Research - École de technologie suprérieure

PhD - École de technologie suprérieure

PhD - Université de Montréal

Principal supervisor :

Collaborating researcher - McGill University

Co-supervisor :

Professional Master's - Université de Montréal

Meghana Bhange

Master's Research - École de technologie suprérieure

Principal supervisor :

Master's Research - École de technologie suprérieure

PhD - École de technologie suprérieure

Principal supervisor :

Github

Somjit Nath

PhD - McGill University

Co-supervisor :

Master's Research - École de technologie suprérieure

Priyesh Vijayan

PhD - McGill University

Principal supervisor :

Zihan Wang

Master's Research - McGill University

Principal supervisor :

Narges Armanfard

Website

Publications

GradTune: Last-layer Fine-tuning for Group Robustness Without Group Annotation

Patrik Joslin Kenfack

This work addresses the limitations of deep neural networks (DNNs) in generalizing beyond training data due to spurious correlations. Recent… (see more) research has demonstrated that models trained with empirical risk minimization learn both core and spurious features, often upweighting spurious ones in the final classification, which can frequently lead to poor performance on minority groups. Deep Feature Reweighting alleviates this issue by retraining the model's last classification layer using a group-balanced held-out validation set. However, relying on spurious feature labels during training or validation limits practical application, as spurious features are not always known or costly to annotate. Our preliminary experiments reveal that ERM-trained models exhibit higher gradient norms on minority group samples in the hold-out dataset. Leveraging these insights, we propose an alternative approach called GradTune, which fine-tunes the last classification layer using high-gradient norm samples. Our results on four well-established benchmarks demonstrate that the proposed method can achieve competitive performance compared to existing methods without requiring group labels during training or validation.

2025-03-06

ICLR.cc/2025/Workshop/SCSL (published)

Towards personalized healthcare without harm via bias modulation

Frank Ngaha

Patrik Joslin Kenfack

Personalized machine learning models have gained significant importance in various domains, including healthcare. However, designing efficie… (see more)nt personalized models remains a challenge. Traditional approaches often involve training multiple sub-models for different population sub-groups, which can be costly and does not always guarantee improved performance across all sub-groups. This paper presents a novel approach to improving model performance at the sub-group level by leveraging bias and training a joint model. Our method involves a two-step process: first, we train a model to predict group attributes, and then we use this model to learn data-dependent biases to modulate a second model for diagnosis prediction. Our results demonstrate that this joint architecture achieves consistent performance gains across all sub-groups in the Heart dataset. Furthermore, in the mortality dataset, it improves performance in two of the four sub-groups. A comparison of our method with the traditional decoupled personalization method demonstrated a greater performance gain in the sub-groups with less harm. This approach offers a more effective and scalable solution for personalization of models, which could have positive impact in healthcare and other areas that require predictive models which take sub-group information into account.

2025-03-06

ICLR.cc/2025/Workshop/SCSL (published)

Learning Multi-agent Multi-machine Tending by Mobile Robots

Abdalwhab Abdalwhab

Giovanni Beltrame

David St-Onge

Robotics can help address the growing worker shortage challenge of the manufacturing industry. As such, machine tending is a task collaborat… (see more)ive robots can tackle that can also highly boost productivity. Nevertheless, existing robotics systems deployed in that sector rely on a fixed single-arm setup, whereas mobile robots can provide more flexibility and scalability. In this work, we introduce a multi-agent multi-machine tending learning framework by mobile robots based on Multi-agent Reinforcement Learning (MARL) techniques with the design of a suitable observation and reward. Moreover, an attention-based encoding mechanism is developed and integrated into Multi-agent Proximal Policy Optimization (MAPPO) algorithm to boost its performance for machine tending scenarios. Our model (AB-MAPPO) outperformed MAPPO in this new challenging scenario in terms of task success, safety, and resources utilization. Furthermore, we provided an extensive ablation study to support our various design decisions.

2025-02-25

AAAI.org/2025/Workshop/MARW (published)

Handling Delay in Real-Time Reinforcement Learning

Ivan Anokhin

Rishav

Matthew D Riemer

Stephen Chung

Irina Rish

Real-time reinforcement learning (RL) introduces several challenges. First, policies are constrained to a fixed number of actions per second… (see more) due to hardware limitations. Second, the environment may change while the network is still computing an action, leading to observational delay. The first issue can partly be addressed with pipelining, leading to higher throughput and potentially better policies. However, the second issue remains: if each neuron operates in parallel with an execution time of

2025-01-22

ICLR.cc/2025/Conference (poster)

KD-LoRA: A Hybrid Approach to Efficient Fine-Tuning with LoRA and Knowledge Distillation

Rambod Azimi

Rishav Rishav

Marek Teichmann

2024-12-10

Proceedings of The 4th NeurIPS Efficient Natural Language and Speech Processing Workshop (published)

Prediction of Final Phosphorus Content of Steel in a Scrap-Based Electric Arc Furnace Using Artificial Neural Networks

Riadh Azzaz

Valentin Hurel

Patrice Ménard

M. Jahazi

Elmira Moosavi-Khoonsari

2024-10-25

ArXiv (preprint)

Empowering Clinicians with Medical Decision Transformers: A Framework for Sepsis Treatment

Aamer Abdul Rahman

Pranav Agarwal

Rita Noumeir

Philippe Jouvet

Vincent Michalski

Offline reinforcement learning has shown promise for solving tasks in safety-critical settings, such as clinical decision support. Its appli… (see more)cation, however, has been limited by the lack of interpretability and interactivity for clinicians. To address these challenges, we propose the medical decision transformer (MeDT), a novel and versatile framework based on the goal-conditioned reinforcement learning paradigm for sepsis treatment recommendation. MeDT uses the decision transformer architecture to learn a policy for drug dosage recommendation. During offline training, MeDT utilizes collected treatment trajectories to predict administered treatments for each time step, incorporating known treatment outcomes, target acuity scores, past treatment decisions, and current and past medical states. This analysis enables MeDT to capture complex dependencies among a patient's medical history, treatment decisions, outcomes, and short-term effects on stability. Our proposed conditioning uses acuity scores to address sparse reward issues and to facilitate clinician-model interactions, enhancing decision-making. Following training, MeDT can generate tailored treatment recommendations by conditioning on the desired positive outcome (survival) and user-specified short-term stability improvements. We carry out rigorous experiments on data from the MIMIC-III dataset and use off-policy evaluation to demonstrate that MeDT recommends interventions that outperform or are competitive with existing offline reinforcement learning methods while enabling a more interpretable, personalized and clinician-directed approach.

2024-07-28

ArXiv (preprint)

Reinforcement Learning for Sequence Design Leveraging Protein Language Models

Jithendaraa Subramanian

Shiva Kanth Sujit

Niloy Irtisam

Umong Sain

Derek Nowrouzezahrai

Riashat Islam

2024-07-03

ArXiv (preprint)

Handling Delay in Reinforcement Learning Caused by Parallel Computations of Neurons

Ivan Anokhin

Rishav

Stephen Chung

Irina Rish

Biological neural networks operate in parallel, a feature that sets them apart from artificial neural networks and can significantly enhance… (see more) inference speed. However, this parallelism introduces challenges: when each neuron operates asynchronously with a fixed execution time, an

2024-06-19

ICML.cc/2024/Workshop/ARLET (poster)

A Survey on Fairness Without Demographics

Patrik Joslin Kenfack

Éts Montréal

The issue of bias in Machine Learning (ML) models is a significant challenge for the machine learning community. Real-world biases can be em… (see more)bedded in the data used to train models, and prior studies have shown that ML models can learn and even amplify these biases. This can result in unfair treatment of individuals based on their inherent characteristics or sensitive attributes such as gender, race, or age. Ensuring fairness is crucial with the increasing use of ML models in high-stakes scenarios and has gained significant attention from researchers in recent years. However, the challenge of ensuring fairness becomes much greater when the assumption of full access to sensitive attributes does not hold. The settings where the hypothesis does not hold include cases where (1) only limited or noisy demographic information is available or (2) demographic information is entirely unobserved due to privacy restrictions. This survey reviews recent research efforts to enforce fairness when sensitive attributes are missing. We propose a taxonomy of existing works and, more importantly, highlight current challenges and future research directions to stimulate research in ML fairness in the setting of missing sensitive attributes.

2024-06-16

TMLR (accepted)

On the Limits of Multi-modal Meta-Learning with Auxiliary Task Modulation Using Conditional Batch Normalization

Jordi Armengol-Estap'e

Vincent Michalski

Ramnath Kumar

Pierre-Luc St-Charles

Doina Precup

Few-shot learning aims to learn representations that can tackle novel tasks given a small number of examples. Recent studies show that cross… (see more)-modal learning can improve representations for few-shot classification. More specifically, language is a rich modality that can be used to guide visual learning. In this work, we experiment with a multi-modal architecture for few-shot learning that consists of three components: a classifier, an auxiliary network, and a bridge network. While the classifier performs the main classification task, the auxiliary network learns to predict language representations from the same input, and the bridge network transforms high-level features of the auxiliary network into modulation parameters for layers of the few-shot classifier using conditional batch normalization. The bridge should encourage a form of lightweight semantic alignment between language and vision which could be useful for the classifier. However, after evaluating the proposed approach on two popular few-shot classification benchmarks we find that a) the improvements do not reproduce across benchmarks, and b) when they do, the improvements are due to the additional compute and parameters introduced by the bridge network. We contribute insights and recommendations for future work in multi-modal meta-learning, especially when using language representations.

2024-05-29

ArXiv (preprint)

Neural semantic tagging for natural language-based search in building information models: Implications for practice

Mehrzad Shahinmoghadam

Ali Motamedi

2024-02-01

Computers in industry (Print) (published)