الباحثون

Pengcheng Xu

المنشورات 4

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Make Sparse Rewards Count: Density-Aware Reward Aggregation for Multi-Reward RL

Tong Zheng, Skylar Zhai, Zhan Cheng وآخرون · 2026

Multi-reward reinforcement learning trains large language models to satisfy multiple behavioral objectives simultaneously. Reward-wise normalization, as used in GDPO, preserves reward-specific relative information within rollout groups, but different objectives can still exhibit uneven learning progress. We study this …

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Guide, Then Let Go: Gap-Adaptive Teacher Scheduling for Sparse-Reward Agentic RL

Youling Huang, Tiankuo Xu, Jiaji Liu وآخرون · 2026

Reinforcement learning for long-horizon agents typically relies on sparse outcome-based rewards. This leads to a severe cold-start problem, as early-stage policies often fail to solve sampled tasks, leaving little useful reward signal for learning. To mitigate this problem, we use on-policy distillation (OPD) to provid …

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UOPD: Uncertainty-Aware Intervention for On-Policy Distillation of Multi-Turn Agents

Wenbo Zhang, Pengcheng Xu, Weizhi Du وآخرون · 2026

On-policy distillation (OPD) trains a student on its own rollouts using dense supervision from a teacher. In multi-turn environments, a mistake at a critical decision step can redirect the subsequent rollout toward poor outcomes. We use low teacher confidence on student actions to select high-uncertainty steps for corr …

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