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R Devon Hjelm

24 accepted papers

2026

GRACE: A Language Model Framework for Explainable Inverse Reinforcement Learning

ICLR 2026poster

Inverse Reinforcement Learning aims to recover reward models from expert demonstrations, but traditional methods yield black-box models that are difficult to interpret and debug. In this work, we introduce GRACE (**G**enerating **R**ewards **A**s **C**od**E**), a method for using Large Language Mode…

Cited by 0SourceScholar
2026

VideoFlexTok: Flexible-Length Coarse-to-Fine Video Tokenization

ICML 2026spotlight

Visual tokenizers map high-dimensional raw pixels into a compressed representation for downstream modeling, e.g., conditional video generation. Beyond compression, tokenizers define what information is preserved and how it is organized. A _de facto_ standard approach is to represent a video with a s…

Cited by 3SourceScholar
2025

On the Modeling Capabilities of Large Language Models for Sequential Decision Making

ICLR 2025poster

Large pretrained models are showing increasingly better performance in reasoning and planning tasks across different modalities, opening the possibility to leverage them for complex sequential decision making problems. In this paper, we investigate the capabilities of Large Language Models (LLMs) fo…

Cited by 1SourcePDFScholar
2024

Grounding Multimodal Large Language Models in Actions

NeurIPS 2024poster

Multimodal Large Language Models (MLLMs) have demonstrated a wide range of capabilities across many domains including Embodied AI. In this work, we study how to best ground a MLLM into different embodiments and their associated action spaces, including both continuous and discrete actions. For conti…

Cited by 12SourcePDFScholar
2024

Large Language Models as Generalizable Policies for Embodied Tasks

ICLR 2024poster

We show that large language models (LLMs) can be adapted to be generalizable policies for embodied visual tasks. Our approach, called Large LAnguage model Reinforcement Learning Policy (LLaRP), adapts a pre-trained frozen LLM to take as input text instructions and visual egocentric observations and…

Cited by 75SourcePDFScholar
2024

Poly-View Contrastive Learning

ICLR 2024poster

Contrastive learning typically matches pairs of related views among a number of unrelated negative views. Views can be generated (e.g. by augmentations) or be observed. We investigate matching when there are more than two related views which we call poly-view tasks, and derive new representation lea…

Cited by 5SourcePDFScholar
2022

Cross-Trajectory Representation Learning for Zero-Shot Generalization in RL

ICLR 2022poster

A highly desirable property of a reinforcement learning (RL) agent -- and a major difficulty for deep RL approaches -- is the ability to generalize policies learned on a few tasks over a high-dimensional observation space to similar tasks not seen during training. Many promising approaches to this c…

2022

Robust Contrastive Learning Against Noisy Views

CVPR 2022poster

Contrastive learning relies on an assumption that positive pairs contain related views that share certain underlying information about an instance, e.g., patches of an image or co-occurring multimodal signals of a video. What if this assumption is violated? The literature suggests that contrastive l…

Cited by 100PDFcodeScholar
2021

CMIM: Cross-Modal Information Maximization For Medical Imaging

ICASSP 2021accepted

In hospitals, data are siloed to specific information systems that make the same information available under different modalities such as the different medical imaging exams the patient undergoes (CT scans, MRI, PET, Ultrasound, etc.) and their associated radiology reports. This offers unique opport…

Cited by 0SourceScholar
2021

Data-Efficient Reinforcement Learning with Self-Predictive Representations

ICLR 2021spotlight

While deep reinforcement learning excels at solving tasks where large amounts of data can be collected through virtually unlimited interaction with the environment, learning from limited interaction remains a key challenge. We posit that an agent can learn more efficiently if we augment reward maxim…

2021

Implicit Regularization via Neural Feature Alignment

AISTATS 2021poster

We approach the problem of implicit regularization in deep learning from a geometrical viewpoint. We highlight a regularization effect induced by a dynamical alignment ofthe neural tangent features introduced by Jacot et al. (2018), along a small number of task-relevant directions. This can be inter…

2021

Object-Centric Image Generation from Layouts

AAAI 2021technical

We begin with the hypothesis that a model must be able to understand individual objects and relationships between objects in order to generate complex scenes with multiple objects well. Our layout-to-image-generation method, which we call Object-Centric Generative Adversarial Network (or OC-GAN), re…

Cited by 119SourcePDFScholar
2021

Pretraining Representations for Data-Efficient Reinforcement Learning

NeurIPS 2021poster

Data efficiency is a key challenge for deep reinforcement learning. We address this problem by using unlabeled data to pretrain an encoder which is then finetuned on a small amount of task-specific data. To encourage learning representations which capture diverse aspects of the underlying MDP, we em…

2021

Understanding by Understanding Not: Modeling Negation in Language Models

NAACL 2021long

Negation is a core construction in natural language. Despite being very successful on many tasks, state-of-the-art pre-trained language models often handle negation incorrectly. To improve language models in this regard, we propose to augment the language modeling objective with an unlikelihood obje…

2020

An end-to-end approach for the verification problem: learning the right distance

ICML 2020poster

In this contribution, we augment the metric learning setting by introducing a parametric pseudo-distance, trained jointly with the encoder. Several interpretations are thus drawn for the learned distance-like model’s output. We first show it approximates a likelihood ratio which can be used for hypo…

2020

Deep Reinforcement and InfoMax Learning

NeurIPS 2020poster

We posit that a reinforcement learning (RL) agent will perform better when it uses representations that are better at predicting the future, particularly in terms of few-shot learning and domain adaptation. To test that hypothesis, we introduce an objective based on Deep InfoMax (DIM) which trains t…

2019

Deep Graph Infomax

ICLR 2019poster

We present Deep Graph Infomax (DGI), a general approach for learning node representations within graph-structured data in an unsupervised manner. DGI relies on maximizing mutual information between patch representations and corresponding high-level summaries of graphs---both derived using establishe…

2019

Learning Representations by Maximizing Mutual Information Across Views

NeurIPS 2019poster

We propose an approach to self-supervised representation learning based on maximizing mutual information between features extracted from multiple views of a shared context. For example, one could produce multiple views of a local spatio-temporal context by observing it from different locations (e.g.…

2019

Learning deep representations by mutual information estimation and maximization

ICLR 2019oral

This work investigates unsupervised learning of representations by maximizing mutual information between an input and the output of a deep neural network encoder. Importantly, we show that structure matters: incorporating knowledge about locality in the input into the objective can significantly imp…

2019

Leveraging exploration in off-policy algorithms via normalizing flows

CoRL 2019

The ability to discover approximately optimal policies in domains with sparse rewards is crucial to applying reinforcement learning (RL) in many real-world scenarios. Approaches such as neural density models and continuous exploration (e.g., Go-Explore) have been proposed to maintain the high explor

2019

On Adversarial Mixup Resynthesis

NeurIPS 2019poster

In this paper, we explore new approaches to combining information encoded within the learned representations of auto-encoders. We explore models that are capable of combining the attributes of multiple inputs such that a resynthesised output is trained to fool an adversarial discriminator for real v…

2019

Unsupervised State Representation Learning in Atari

NeurIPS 2019poster

State representation learning, or the ability to capture latent generative factors of an environment is crucial for building intelligent agents that can perform a wide variety of tasks. Learning such representations in an unsupervised manner without supervision from rewards is an open problem. We in…

2017

A deep-learning approach to translate between brain structure and functional connectivity

ICASSP 2017accepted

While the majority of exploratory approaches search for correlations among features of different modalities, indirect/nonlinear relations between structure and function have not yet been fully investigated. In this work, we employ a neural machine translation model [1] to relate two modalities: stru…

Cited by 0SourceScholar