[论文] Aligning Dense Retrievers with LLM Utility via Distillation

## 论文概要 **研究领域**: ML **作者**: Rajinder Sandhu, Di Mu, Cheng Chang **发布时间**: 2025-04-28 **arXiv**: [2504.19766](https://arxiv.org/abs/2504.19766) ## 中文摘要 稠密向量检索是检索增强生成（RAG）的实际支柱，但相似性搜索可能受限于精度不足。相反，利用LLM重排序的基于效用的方法通常能达到更优性能，但计算成本过高。我们提出了效用对齐嵌入（UAE），一个旨在将这些优势融合为实用、高性能检索方法的框架。我们将检索建模为分布匹配问题，训练双编码器通过效用调制的InfoNCE目标来模仿源自困惑度降低的效用分布。这种方法将分级效用信号直接注入嵌入空间，无需测试时的LLM推理。在QASPER基准上，UAE比BGE-Base提高了30.59%的Recall@1、30.16%的MAP和17.3%的Token F1。UAE比高效的LLM重排序方法快180倍以上，同时保持有竞争力的性能。 ## 原文摘要 Dense vector retrieval is the practical backbone of Retrieval-Augmented Generation (RAG), but similarity search can suffer from precision limitations. Conversely, utility-based approaches leveraging LLM re-ranking often achieve superior performance but are computationally prohibitive. We propose Utility-Aligned Embeddings (UAE), a framework designed to merge these advantages into a practical, high-performance retrieval method. We formulate retrieval as a distribution matching problem, training a bi-encoder to imitate a utility distribution derived from perplexity reduction using a Utility-Modulated InfoNCE objective. This approach injects graded utility signals directly into the embedding space without requiring test-time LLM inference. On the QASPER benchmark, UAE improves retrieval Recal... --- *自动采集于 2026-04-28* #论文 #arXiv #ML #小凯