The power of Retrieval-Augmented Generation (RAG) has revolutionized Artificial Intelligence, particularly in generating reliable and up-to-date content. This survey reviews existing research studies in RAG, focusing on architectures, training strategies, and applications. It delves into the foundations and recent advances of Large Language Models (LLMs), which have demonstrated remarkable language understanding and generation abilities but still face limitations such as hallucinations and outdated internal knowledge. RAG harnesses external and authoritative knowledge bases to augment LLMs’ generation quality, offering a significant convenience for various tasks.
What’s the Power of Retrieval-Augmented Generation?
The concept of Retrieval-Augmented Generation (RAG) has revolutionized the field of Artificial Intelligence (AI), particularly in the era of AI-generated content. RAG enables reliable and up-to-date external knowledge, providing a significant convenience for various tasks. This survey aims to comprehensively review existing research studies in RAG, focusing on three primary technical perspectives: architectures, training strategies, and applications.
In this section, we will delve into the foundations and recent advances of Large Language Models (LLMs). LLMs have demonstrated remarkable abilities in language understanding and generation, but they still face inherent limitations such as hallucinations and outdated internal knowledge. RAG has emerged to harness external and authoritative knowledge bases, rather than solely relying on the models’ internal knowledge to augment the generation quality of LLMs.
The survey begins by introducing the foundations of LLMs, including their architectures, training strategies, and applications. We will explore how LLMs have been pre-trained using massive datasets and fine-tuned for specific tasks, such as language translation and text summarization. The survey will also discuss the challenges faced by LLMs, including the need to incorporate in-context learning and prompting techniques.
Architectures of RAG
RAG architectures are designed to integrate external knowledge with internal model capabilities. One popular approach is to use a multi-stage architecture, where the first stage retrieves relevant information from an external knowledge base, and the second stage generates text based on this retrieved information. Another approach is to use a hybrid architecture that combines the strengths of both RAG and LLMs.
For instance, researchers at Baidu Inc., China, have developed a novel RAG architecture that leverages the power of large-scale language models and external knowledge bases. Their approach involves using a transformer-based model to retrieve relevant information from an external knowledge base, which is then used to generate text. This hybrid architecture has shown promising results in generating high-quality text.
Training Strategies for RAG
Training strategies for RAG involve fine-tuning the model on specific tasks and datasets. One popular approach is to use a masked language modeling task, where the model is trained to predict missing tokens in a given sentence. Another approach is to use a next-sentence prediction task, where the model is trained to predict whether two sentences are related.
Researchers at The Hong Kong Polytechnic University have developed a novel training strategy for RAG that involves using a combination of masked language modeling and next-sentence prediction tasks. Their approach has shown promising results in generating high-quality text.
Applications of RAG
RAG has numerous applications in various fields, including natural language processing, information retrieval, and machine learning. One popular application is to use RAG for text summarization, where the model generates a concise summary of a given text based on retrieved information from an external knowledge base.
Researchers at National University of Singapore have developed a novel RAG-based system for text summarization that leverages the power of large-scale language models and external knowledge bases. Their approach involves using a transformer-based model to retrieve relevant information from an external knowledge base, which is then used to generate a concise summary.
Challenges and Limitations
Despite the promising results of RAG, there are several challenges and limitations that need to be addressed. One major challenge is the need for high-quality training data, which can be time-consuming and expensive to collect. Another challenge is the need for careful evaluation metrics, as RAG models can generate text that is not always accurate or relevant.
Researchers at The Hong Kong Polytechnic University have identified several promising directions for future research in RAG, including the development of more robust training strategies and the integration of RAG with other AI technologies.
Publication details: “A Survey on RAG Meeting LLMs: Towards Retrieval-Augmented Large Language Models”
Publication Date: 2024-08-24
Authors: Wenqi Fan, Yujuan Ding, Liangbo Ning, Shijie Wang, et al.
Source:
DOI: https://doi.org/10.1145/3637528.3671470
