Core Viewpoint - The article discusses the Retrieval Augmented Generation (RAG) method, which combines retrieval-based models and generative models to enhance the quality and relevance of generated text. It addresses issues such as hallucination, knowledge timeliness, and long text processing in large models [1]. Group 1: Background and Challenges - RAG was proposed by Meta in 2020 to enable language models to access external information beyond their internal knowledge [1]. - RAG faces three main challenges: retrieval quality, enhancement process, and generation quality [2]. Group 2: Challenges in Retrieval Quality - Semantic ambiguity can arise from vector representations, leading to irrelevant results [5]. - User input has become more complex, transitioning from keywords to natural dialogue, which complicates retrieval [5]. - Document segmentation methods can affect the matching degree between document blocks and user queries [5]. - Extracting and representing multimodal content (e.g., tables, charts) poses significant challenges [5]. - Integrating context from retrieved paragraphs into the current generation task is crucial for coherence [5]. - Redundancy and repetition in retrieved content can lead to duplicated information in generated outputs [5]. - Determining the importance of multiple retrieved paragraphs for the generation task is challenging [5]. - Over-reliance on retrieval content can exacerbate hallucination issues [5]. - Irrelevance of generated answers to the query is a concern [5]. - Toxicity or bias in generated answers is another issue [5]. Group 3: Overall Architecture - The product architecture consists of four layers, including model layer, offline understanding layer, online Q&A layer, and scenario layer [7]. - The RAG framework is divided into three main components: query understanding, retrieval model, and generation model [10]. Group 4: Query Understanding - The query understanding module aims to improve retrieval by interpreting user queries and generating structured queries [14]. - Intent recognition helps select relevant modules based on user queries [15]. - Query rewriting utilizes LLM to rephrase user queries for better retrieval [16]. - Query expansion breaks complex questions into simpler sub-questions for more effective retrieval [22]. Group 5: Retrieval Model - The retrieval model's effectiveness depends on the accuracy of embedding models [33]. - Document loaders facilitate loading document data from various sources [38]. - Text converters prepare documents for retrieval by segmenting them into smaller, semantically meaningful chunks [39]. - Document embedding models create vector representations of text to enable semantic searches [45]. - Vector databases support efficient storage and search of embedded data [47]. Group 6: Generation Model - The generation model utilizes retrieved information to generate coherent responses to user queries [60]. - Different strategies for prompt assembly are employed to enhance response generation [62][63]. Group 7: Attribution Generation - Attribution in RAG is crucial for aligning generated content with reference information, ensuring accuracy [73]. - Dynamic computation methods can enhance the generation process by matching generated text with reference sources [76]. Group 8: Evaluation - The article emphasizes the importance of defining metrics and evaluation methods for assessing RAG system performance [79]. - Various evaluation frameworks, such as RGB and RAGAS, are introduced to benchmark RAG systems [81]. Group 9: Conclusion - The article summarizes key modules in RAG practice and highlights the need for continuous research and development to refine these technologies [82].