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Hojoon Lee

14 accepted papers

2026

A Champion-Level Vision-Based Reinforcement Learning Agent for Competitive Racing in Gran Turismo 7

ICRA 2026poster

Deep reinforcement learning has achieved super-human racing performance in high-fidelity simulators like Gran Turismo 7 (GT7). It typically utilizes global features that require instrumentation external to a car, such as precise localization of agents and opponents, limiting real-world applicability…

2026

ACG: Action Coherence Guidance for Flow-Based Vision-Language-Action Models

ICRA 2026poster

Diffusion and flow matching models have emerged as powerful robot policies, enabling Vision-Language-Action (VLA) models to generalize across diverse scenes and instructions. Yet, when trained via imitation learning, their high generative capacity makes them sensitive to noise in human demonstration…

2026

FIRE: Frobenius-Isometry Reinitialization for Balancing the Stability–Plasticity Tradeoff

ICLR 2026oral

Deep neural networks trained on nonstationary data must balance stability (i.e., retaining prior knowledge) and plasticity (i.e., adapting to new tasks). Standard reinitialization methods, which reinitialize weights toward their original values, are widely used but difficult to tune: conservative re…

Cited by 0SourceScholar
2026

FlashSAC: Fast and Stable Off-Policy Reinforcement Learning for High-Dimensional Robot Control

RSS 2026poster

Simulation-based reinforcement learning (RL) is central for robotic control when expert demonstrations are unavailable. However, scaling RL to high-dimensional robots remains challenging. On-policy methods such as PPO are reliable but require large amounts of simulation because they discard past dat…

Cited by 0SourceScholar
2025

A Champion-Level Vision-Based Reinforcement Learning Agent for Competitive Racing in Gran Turismo 7

RA-L 2025

Deep reinforcement learning has achieved superhuman racing performance in high-fidelity simulators like Gran Turismo 7 (GT7). It typically utilizes global features that require instrumentation external to a car, such as precise localization of agents and opponents, limiting real-world applicability.

Cited by 6SourceScholar
2025

Hyperspherical Normalization for Scalable Deep Reinforcement Learning

ICML 2025spotlight

Scaling up the model size and computation has brought consistent performance improvements in supervised learning. However, this lesson often fails to apply to reinforcement learning (RL) because training the model on non-stationary data easily leads to overfitting and unstable optimization. In resp…

Cited by 0SourcePDFScholar
2025

SimBa: Simplicity Bias for Scaling Up Parameters in Deep Reinforcement Learning

ICLR 2025spotlight

Recent advances in CV and NLP have been largely driven by scaling up the number of network parameters, despite traditional theories suggesting that larger networks are prone to overfitting. These large networks avoid overfitting by integrating components that induce a simplicity bias, guiding models…

2024

Adapting Pretrained ViTs with Convolution Injector for Visuo-Motor Control

ICML 2024poster

Vision Transformers (ViT), when paired with large-scale pretraining, have shown remarkable performance across various computer vision tasks, primarily due to their weak inductive bias. However, while such weak inductive bias aids in pretraining scalability, this may hinder the effective adaptation o…

2024

Do's and Don'ts: Learning Desirable Skills with Instruction Videos

NeurIPS 2024poster

Unsupervised skill discovery is a learning paradigm that aims to acquire diverse behaviors without explicit rewards. However, it faces challenges in learning complex behaviors and often leads to learning unsafe or undesirable behaviors. For instance, in various continuous control tasks, current unsu…

2024

Investigating Pre-Training Objectives for Generalization in Vision-Based Reinforcement Learning

ICML 2024poster

Recently, various pre-training methods have been introduced in vision-based Reinforcement Learning (RL). However, their generalization ability remains unclear due to evaluations being limited to in-distribution environments and non-unified experimental setups. To address this, we introduce the Atari…

2024

Slow and Steady Wins the Race: Maintaining Plasticity with Hare and Tortoise Networks

ICML 2024poster

This study investigates the loss of generalization ability in neural networks, revisiting warm-starting experiments from Ash & Adams. Our empirical analysis reveals that common methods designed to enhance plasticity by maintaining trainability provide limited benefits to generalization. While reinit…

2023

Learning to Discover Skills through Guidance

NeurIPS 2023poster

In the field of unsupervised skill discovery (USD), a major challenge is limited exploration, primarily due to substantial penalties when skills deviate from their initial trajectories. To enhance exploration, recent methodologies employ auxiliary rewards to maximize the epistemic uncertainty or ent…

2023

On the Importance of Feature Decorrelation for Unsupervised Representation Learning in Reinforcement Learning

ICML 2023poster

Recently, unsupervised representation learning (URL) has improved the sample efficiency of Reinforcement Learning (RL) by pretraining a model from a large unlabeled dataset. The underlying principle of these methods is to learn temporally predictive representations by predicting future states in the…

2023

PLASTIC: Improving Input and Label Plasticity for Sample Efficient Reinforcement Learning

NeurIPS 2023poster

In Reinforcement Learning (RL), enhancing sample efficiency is crucial, particularly in scenarios when data acquisition is costly and risky. In principle, off-policy RL algorithms can improve sample efficiency by allowing multiple updates per environment interaction. However, these multiple updates…