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Johan Obando-Ceron

13 accepted papers

2026

Asymmetric Proximal Policy Optimization: mini-critics boost LLM reasoning

ICLR 2026poster

Reinforcement learning (RL) has become a central paradigm for post-training large language models (LLMs) to elicit stronger reasoning. Yet, most recent RL for LLMs (RL4LLM) methods avoid explicit critics, replacing them with average advantage baselines. This shift is largely pragmatic: conventional…

Cited by 0SourceScholar
2026

Grounding Computer Use Agents on Human Demonstrations

ICLR 2026poster

Building reliable computer-use agents requires grounding: accurately connecting natural language instructions to the correct on-screen elements. While large datasets exist for web and mobile interactions, high-quality resources for desktop environments are limited. To address this gap, we introduce…

Cited by 0SourcecodeScholar
2026

Kaleidoscope: In-language Exams for Massively Multilingual Vision Evaluation

ICLR 2026poster

The evaluation of vision-language models (VLMs) has mainly relied on English-language benchmarks, leaving significant gaps in both multilingual and multicultural coverage. While multilingual benchmarks have expanded, both in size and language, many rely on translations of English datasets, failing t…

Cited by 0SourcecodeScholar
2026

Simplicial Embeddings Improve Sample Efficiency in Actor–Critic Agents

ICLR 2026poster

Recent works have proposed accelerating the wall-clock training time of actor-critic methods via the use of large-scale environment parallelization; unfortunately, these can sometimes still require large number of environment interactions to achieve a desired level of performance. Noting that well-s…

Cited by 0SourceScholar
2026

Stable Deep Reinforcement Learning via Isotropic Gaussian Representations

ICML 2026spotlight

Deep reinforcement learning systems often suffer from unstable training dynamics due to non-stationarity, where learning objectives and data distributions evolve over time. We show that under non-stationary targets, isotropic Gaussian embeddings are provably advantageous. In particular, they induce …

Cited by 0SourceScholar
2025

All Languages Matter: Evaluating LMMs on Culturally Diverse 100 Languages

CVPR 2025highlight

Existing Large Multimodal Models (LMMs) generally focus on only a few regions and languages. As LMMs continue to improve, it is increasingly important to ensure they understand cultural contexts, respect local sensitivities, and support low-resource languages, all while effectively integrating corr…

2025

Generating Creative Chess Puzzles

NeurIPS 2025poster

While Generative AI rapidly advances in various domains, generating truly creative, aesthetic, and counter-intuitive outputs remains a challenge. This paper presents an approach to tackle these difficulties in the domain of chess puzzles. We start by benchmarking Generative AI architectures, and the…

Cited by 0SourceScholar
2025

Measure gradients, not activations! Enhancing neuronal activity in deep reinforcement learning

NeurIPS 2025poster

Deep reinforcement learning (RL) agents frequently suffer from neuronal activity loss, which impairs their ability to adapt to new data and learn continually. A common method to quantify and address this issue is the $\tau$-dormant neuron ratio, which uses activation statistics to measure the expres…

Cited by 0SourcecodeScholar
2025

Mitigating Plasticity Loss in Continual Reinforcement Learning by Reducing Churn

ICML 2025poster

Plasticity, or the ability of an agent to adapt to new tasks, environments, or distributions, is crucial for continual learning. In this paper, we study the loss of plasticity in deep continual RL from the lens of churn: network output variability induced by the data in each training batch. We demon…

Cited by 0SourcePDFScholar
2025

Stable Gradients for Stable Learning at Scale in Deep Reinforcement Learning

NeurIPS 2025spotlight

Scaling deep reinforcement learning networks is challenging and often results in degraded performance, yet the root causes of this failure mode remain poorly understood. Several recent works have proposed mechanisms to address this, but they are often complex and fail to highlight the causes underly…

Cited by 0SourceScholar
2025

The Courage to Stop: Overcoming Sunk Cost Fallacy in Deep Reinforcement Learning

ICML 2025poster

Off-policy deep reinforcement learning (RL) agents typically leverage replay buffers for reusing past experiences during learning. This can help sample efficiency when the collected data is informative and aligned with the learning objectives; when that is not the case, it has the effect of ``pollut…

Cited by 0SourcePDFScholar
2025

The Impact of On-Policy Parallelized Data Collection on Deep Reinforcement Learning Networks

ICML 2025poster

The use of parallel actors for data collection has been an effective technique used in reinforcement learning (RL) algorithms. The manner in which data is collected in these algorithms, controlled via the number of parallel environments and the rollout length, induces a form of bias-variance trade-o…

Cited by 0SourcePDFScholar
2025

Trajectory Balance with Asynchrony: Decoupling Exploration and Learning for Fast, Scalable LLM Post-Training

NeurIPS 2025poster

Reinforcement learning (RL) is a critical component of large language model (LLM) post-training. However, on-policy algorithms used for post-training are not naturally robust to a diversified content of experience replay buffers, which asynchronous off-policy actors can efficiently populate in paral…

Cited by 0SourcecodeScholar