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arXiv 2602.17658cs.LGcs.AIcs.ITmath.IT

MARS:面向奖励建模的边界与语义感知数据增强

MARS: Margin and Semantic-Aware Data Augmentation for Reward Modeling

University of Arizona(亚利桑那大学);Northeastern University London(伦敦东北大学)

Payel Bhattacharjee, Osvaldo Simeone, Ravi Tandon

AI总结:

提出MARS框架,通过优先增强低边界偏好对并利用语义距离细化,提升奖励模型质量和对齐性能。

摘要:

奖励建模是RLHF、RLAIF和基于PPO的策略优化等对齐流程的核心,但其可靠性受限于有限且异构的人类偏好数据,这些数据难以大规模收集。虽然合成增强可以扩展偏好监督,但现有方法通常均匀增强或在表示层面增强,而不针对奖励模型不确定或容易误排序的示例。在本文中,我们介绍了MARS(面向奖励建模的边界与语义感知数据增强),一种自适应增强框架,优先考虑低边界偏好对,并使用语义距离作为第二层细化,以增强选择响应和拒绝响应之间的对比。在多个偏好数据集、奖励模型骨干、下游对齐设置以及包括RewardBench和AlpacaEval在内的基准测试中,MARS在奖励模型质量和对齐性能上都优于现有基线。我们的结果表明,当同时由模型边界和语义结构引导时,奖励模型增强最为有效。

英文摘要:

Reward modeling is central to RLHF, RLAIF, and PPO-based alignment, but its reliability is often limited by scarce and heterogeneous human preference data. In this paper, we introduce MARS (Margin and Semantic-Aware Data Augmentation for Reward Modeling), an adaptive augmentation framework for controlled low-resource reward modeling. MARS allocates more augmentation to low-margin preference pairs and uses semantic-distance-based refinement to improve chosen-rejected contrast before generating synthetic preference samples. Across three preference datasets, two reward-model backbones, and downstream alignment evaluations, MARS improves average RewardBench performance and alignment win rates over uniform augmentation, WoN, and AdaBoost-style baselines. Ablations and independent-judge evaluations suggest that the gains are not solely explained by semantic refinement alone or GPT-4.1 judge coupling.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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