AI summary · arXiv: 2005.11401v1 · cs.CL
Retrieval-Augmented Generation for Knowledge-Intensive NLP Tasks
The essentials
- Large pre-trained language models have limitations in accessing and manipulating knowledge
- Performance of these models is not as good as task-specific architectures on knowledge-intensive tasks
- The authors propose retrieval-augmented generation (RAG) models that combine pre-trained parametric and non-parametric memory for language generation
- RAG models use a pre-trained seq2seq model as parametric memory and a dense vector index of Wikipedia accessed through a pre-trained neural retriever as non-parametric memory
- Two formulations of RAG models are compared: one with the same retrieved passages throughout the generated sequence, and another with different passages per token
- Fine-tuning and evaluation on various knowledge-intensive NLP tasks show state-of-the-art results on three open domain QA tasks, outperforming parametric seq2seq models and task-specific retrieve and extract architectures
- RAG models generate more specific, diverse, and factual language compared to a state-of-the-art parametric-only seq2seq baseline for language generation tasks
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Retrieval-augmented Generation across Heterogeneous KnowledgeW. Yu · 2022 · North American Chapter of the Association for Computational Linguistics · cited 73 times · Not summarized yet
Retrieval-augmented Generation across Heterogeneous Knowledge discusses the limitations of retrieving from a single homogeneous corpus, whereas this paper uses Wikipedia as its knowledge source.
Abstract
Retrieval-augmented generation (RAG) methods have been receiving increasing attention from the NLP community and achieved state-of-the-art performance on many NLP downstream tasks. Compared with conventional pre-trained generation models, RAG methods have remarkable advantages such as easy knowledge acquisition, strong scalability, and low training cost. Although existing RAG models have been applied to various knowledge-intensive NLP tasks, such as open-domain QA and dialogue systems, most of the work has focused on retrieving unstructured text documents from Wikipedia. In this paper, I first elaborate on the current obstacles to retrieving knowledge from a single-source homogeneous corpus.…
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Dynamic and Parametric Retrieval-Augmented Generation surveys newer directions beyond static retrieval, including adaptive access and deeper integration of external knowledge.
Abstract
Retrieval-Augmented Generation (RAG) has become a foundational paradigm for enhancing large language models (LLMs) with external knowledge, playing an important role in modern information retrieval and knowledge-intensive NLP applications. Standard RAG systems typically adopt a static retrieve-then-generate pipeline and rely on in-context knowledge injection, which can be suboptimal for complex tasks that require multihop reasoning, adaptive information access, and deeper integration of external knowledge. Motivated by these limitations, the research community has moved beyond static retrieval and in-context knowledge injection. Among the emerging directions, this tutorial delves into two ra…
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Retrieval-augmented generation for natural language processing surveys RAG retrievers and retrieval-fusion techniques, while this paper introduces and evaluates a particular RAG model.
Abstract
Large language models (LLMs) have achieved strong empirical performance in various fields, benefiting from their huge amount of parameters that store knowledge. However, LLMs still suffer from several key issues, such as hallucination problems, knowledge update issues, and lacking domain-specific expertise. The appearance of retrieval-augmented generation (RAG), which leverages an external knowledge base to augment LLMs, mitigates these limitations. This paper presents a systematic review of RAG techniques for natural language processing (NLP), with a focus on retrievers and retrieval fusions. We introduce a novel taxonomy of retrieval fusions, such as query-based, logits-based, latent, and …
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Abstract
Large Language Models (LLMs) demonstrate significant capabilities but face challenges such as hallucination, outdated knowledge, and non-transparent, untraceable reasoning processes. Retrieval-Augmented Generation (RAG) has emerged as a promising solution by incorporating knowledge from external databases. This enhances the accuracy and credibility of the models, particularly for knowledge-intensive tasks, and allows for continuous knowledge updates and integration of domain-specific information. RAG synergistically merges LLMs' intrinsic knowledge with the vast, dynamic repositories of external databases. This comprehensive review paper offers a detailed examination of the progression of RA…
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Abstract
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SegMem-RAG routes queries across unlabeled corpora and updates memory through experience, unlike this paper’s Wikipedia-based retrieval setup.
Abstract
Retrieval-Augmented Generation (RAG) improves the factual accuracy of large language models by grounding responses in external content. However, most RAG systems assume access to static and well-organized corpora with fixed retrieval logic. In practice, real-world sources are heterogeneous and unlabeled, including user-uploaded documents, manuals, and datasets. Effective access in such settings requires adaptive and self-directed retrieval behavior. We present SegMem‑RAG, a memory-augmented RAG framework that learns to route queries across multiple unlabeled corpora based on experience. It incrementally updates a structured memory and uses self-reflection to guide retrieval over time without…
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Abstract
Retrieval-Augmented Generation (RAG) prevails in Large Language Models. It mainly consists of retrieval and generation. The retrieval modules (a.k.a. retrievers) aim to find useful information used to facilitate generation modules (a.k.a. generators). As such, generators' performance largely depends on the effectiveness and efficiency of retrievers. However, the retrieval paradigm that we design and use remains flat, which treats the retrieval procedures as a one-off deal with constant granularity. Despite effectiveness, we argue that they suffer from two limitations: (1) flat retrieval exerts a significant burden on one retriever; (2) constant granularity limits the ceiling of retrieval per…
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MemoRAG uses long-term memory for knowledge discovery when queries or knowledge are ambiguous, extending beyond this paper’s dense retrieval of Wikipedia passages.
Abstract
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Prior work it builds on
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REALM: Retrieval-Augmented Language Model Pre-TrainingKelvin Guu, Kenton Lee, Zora Tung et al. · 2020 · International Conference on Machine Learning · cited 3,608 times · Not summarized yet
REALM pre-trains a language model with a latent retriever over documents, an earlier approach to combining parametric language models with external knowledge.
Abstract
Language model pre-training has been shown to capture a surprising amount of world knowledge, crucial for NLP tasks such as question answering. However, this knowledge is stored implicitly in the parameters of a neural network, requiring ever-larger networks to cover more facts. To capture knowledge in a more modular and interpretable way, we augment language model pre-training with a latent knowledge retriever, which allows the model to retrieve and attend over documents from a large corpus such as Wikipedia, used during pre-training, fine-tuning and inference. For the first time, we show how to pre-train such a knowledge retriever in an unsupervised manner, using masked language modeling a…
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How Much Knowledge Can You Pack into the Parameters of a Language Model?Adam Roberts, Colin A. Raffel, Noam Shazeer · 2020 · Conference on Empirical Methods in Natural Language Processing · cited 1,157 times · Not summarized yet
How Much Knowledge Can You Pack into the Parameters of a Language Model? measures question answering from parametric knowledge alone, providing a baseline contrast to this paper’s external retrieval.
Abstract
It has recently been observed that neural language models trained on unstructured text can implicitly store and retrieve knowledge using natural language queries. In this short paper, we measure the practical utility of this approach by fine-tuning pre-trained models to answer questions without access to any external context or knowledge. We show that this approach scales surprisingly well with model size and outperforms models that explicitly look up knowledge on the open-domain variants of Natural Questions and WebQuestions. To facilitate reproducibility and future work, we release our code and trained models.
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Latent Retrieval for Weakly Supervised Open Domain Question Answering jointly learns a retriever and reader from question-answer pairs, and this paper cites it.
Abstract
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Retrieve and Refine: Improved Sequence Generation Models For DialogueJ. Weston, Emily Dinan, Alexander H. Miller · 2018 · SCAI@EMNLP · cited 212 times · Not summarized yet
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Abstract
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Dense Passage Retrieval for Open-Domain Question AnsweringVladimir Karpukhin, Barlas Oğuz, Sewon Min et al. · 2020 · Conference on Empirical Methods in Natural Language Processing · cited 7,738 times · AI summary available
Dense Passage Retrieval introduces a dual-encoder dense retriever for open-domain QA, the kind of retrieval component used by this paper.
Abstract
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Papers that cite it
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Active Retrieval Augmented Generation cites this paper and develops repeated retrieval during long-text generation, rather than relying on retrieval at the input.
Abstract
Despite the remarkable ability of large language models (LMs) to comprehend and generate language, they have a tendency to hallucinate and create factually inaccurate output. Augmenting LMs by retrieving information from external knowledge resources is one promising solution. Most existing retrieval-augmented LMs employ a retrieve-and-generate setup that only retrieves information once based on the input. This is limiting, however, in more general scenarios involving generation of long texts, where continually gathering information throughout the generation process is essential. There have been some past efforts to retrieve information multiple times while generating outputs, which mostly re…
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MAPS: Macro-Adaptive Parallel Reasoning for Regulating Search Momentum in Retrieval-Augmented GenerationXin-Ze Li, Ding-Wen Zhang, Zheng-Hao Liu et al. · 2026 · Not summarized yet
MAPS cites this paper and develops parallel reasoning and retrieval to address redundant sub-queries and limited query exploration.
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Retrieval-Augmented Generation (RAG) improves the performance of Large Language Models (LLMs) by retrieving external knowledge. Recently, some RAG methods interleave reasoning and retrieval, enabling LLMs to progressively generate sub-queries and retrieve external knowledge. However, these methods may suffer from redundant or ineffective sub-queries and insufficiently diverse query exploration. Moreover, due to the tightly interleaved nature of reasoning and retrieval, it remains unclear how the evolving reasoning process influences query intent. To characterize the evolution of query intent during reasoning, we introduce search momentum, which captures the accumulated retrieval tendency ind…
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Leveraging Passage Retrieval with Generative Models for Open Domain Question Answering combines retrieved passages with generative models for open-domain QA, an approach this paper builds on.
Abstract
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