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Hieu Trung Nguyen

8 accepted papers

2026

Adaptive Rollout Allocation for Online Reinforcement Learning with Verifiable Rewards

ICLR 2026poster

Sampling efficiency is a key bottleneck in reinforcement learning with verifiable rewards. Existing group-based policy optimization methods, such as GRPO, allocate a fixed number of rollouts for all training prompts. This uniform allocation implicitly treats all prompts as equally informative, and c…

Cited by 0SourceScholar
2025

Mixture-of-Personas Language Models for Population Simulation

ACL 2025finding

Advances in Large Language Models (LLMs) paved the way for their emerging applications in various domains, such as human behavior simulations, where LLMs could augment human-generated data in social science research and machine learning model training. However, pretrained LLMs often fail to capture…

2025

Reasoning Planning for Language Models

NeurIPS 2025spotlight

Selecting an appropriate reasoning method for a given query remains a key challenge in language model generation. Existing approaches typically generate multiple candidate responses and use an aggregation strategy to select the output answer, often assuming that more candidate answers yield higher a…

Cited by 0SourcecodeScholar
2025

Structured Pruning for Diverse Best-of-N Reasoning Optimization

ACL 2025finding

Model pruning in transformer-based language models, traditionally seen as a means of computational savings, can enhance the model’s reasoning capabilities. In this work, we uncover the surprising phenomenon that the selective pruning of certain attention heads leads to improvements in reasoning perf…

2025

Task-driven Layerwise Additive Activation Intervention

NAACL 2025short

Modern language models (LMs) have significantly advanced generative modeling in natural language processing (NLP). Despite their success, LMs often struggle with adaptation to new contexts in real-time applications. A promising approach to task adaptation is activation intervention, which steers the…

2024

Cold-start Recommendation by Personalized Embedding Region Elicitation

UAI 2024poster

Rating elicitation is a success element for recommender systems to perform well at cold-starting, in which the systems need to recommend items to a newly arrived user with no prior knowledge about the user’s preference. Existing elicitation methods employ a fixed set of items to learn the user’s pre…

Cited by 0SourcePDFScholar
2024

Explaining Graph Neural Networks via Structure-aware Interaction Index

ICML 2024poster

The Shapley value is a prominent tool for interpreting black-box machine learning models thanks to its strong theoretical foundation. However, for models with structured inputs, such as graph neural networks, existing Shapley-based explainability approaches either focus solely on node-wise importanc…

2024

Generative Conditional Distributions by Neural (Entropic) Optimal Transport

ICML 2024poster

Learning conditional distributions is challenging because the desired outcome is not a single distribution but multiple distributions that correspond to multiple instances of the covariates. We introduce a novel neural entropic optimal transport method designed to effectively learn generative models…