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arXiv 2605.04539cs.CLcs.AI
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RLearner-LLM: 通过混合直接偏好优化平衡大语言模型中的逻辑性与流畅性

RLearner-LLM: Balancing Logical Grounding and Fluency in Large Language Models via Hybrid Direct Preference Optimization

University of Auckland(奥克兰大学);Aalto University(阿alto大学)

Qiming Bao, Juho Leinonen, Paul Denny, Michael J. Witbrock

AI总结:

本文提出RLearner-LLM,通过融合DeBERTa-v3 NLI信号与验证器LLM评分,解决直接偏好优化在知识密集型生成中的逻辑对齐问题,实现NLI指标显著提升。

摘要:

直接偏好优化(DPO)作为PPO-based RLHF的高效替代方案,在知识密集型生成中存在系统性冗余偏差,偏好信号奖励流畅性而非逻辑正确性。本文提出RLearner-LLM与混合DPO:自动化偏好流程融合DeBERTa-v3 NLI信号与验证器LLM评分,去除人工标注并克服单一信号优化的

英文摘要:

Direct Preference Optimization (DPO), the efficient alternative to PPO-based RLHF, falls short on knowledge-intensive generation: standard preference signals from human annotators or LLM judges exhibit a systematic verbosity bias that rewards fluency over logical correctness. This blindspot leaves a logical alignment gap -- SFT models reach NLI entailment of only 0.05-0.22 despite producing fluent text. We propose RLearner-LLM with Hybrid-DPO: an automated preference pipeline that fuses a DeBERTa-v3 NLI signal with a verifier LLM score, removing human annotation while overcoming the "alignment tax" of single-signal optimization. Evaluated across five academic domains (Biology, Medicine, Law) with three base architectures (LLaMA-2-13B, Qwen3-8B, Gemma 4 E4B-it), RLearner-LLM yields up to 6x NLI improvement over SFT, with NLI gains in 11 of 15 cells and consistent answer-coverage gains. On Gemma 4 E4B-it (4.5B effective params), Hybrid-DPO lifts NLI in four of five domains (+11.9% to +2.4x) with faster inference across all five, scaling down to compact base models without losing the alignment-tax mitigation. Our Qwen3-8B RLearner-LLM wins 95% of pairwise comparisons against its own SFT baseline; GPT-4o-mini in turn wins 95% against our concise output -- alongside the 69% win the same judge gives a verbose SFT over our DPO model, this replicates verbosity bias on a frontier comparator and motivates logic-aware metrics (NLI, ACR) over LLM-as-a-judge for knowledge-intensive generation.

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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