🤖 AI Summary
Prior surveys on information retrieval (IR) models conflate architectural design with training methodologies, obscuring the intrinsic evolution of structural innovations in relevance modeling.
Method: We systematically trace the architectural progression of IR models—spanning backbone feature extractors and end-to-end relevance modeling—from classical BM25 through CNN/RNN-based rankers to modern BERT dual-encoder and interaction-based architectures, ColBERT, Cross-Encoders, and LLM-based retrievers—explicitly decoupling architecture from training strategy.
Contribution/Results: We propose the first longitudinal IR-specific architectural taxonomy, explicitly addressing scalability and adaptability challenges in multimodal, multilingual, and emerging application scenarios. Our framework provides an actionable technology roadmap for industrial system selection and rigorously identifies open research questions and future directions for the academic community.
📝 Abstract
This survey examines the evolution of model architectures in information retrieval (IR), focusing on two key aspects: backbone models for feature extraction and end-to-end system architectures for relevance estimation. The review intentionally separates architectural considerations from training methodologies to provide a focused analysis of structural innovations in IR systems.We trace the development from traditional term-based methods to modern neural approaches, particularly highlighting the impact of transformer-based models and subsequent large language models (LLMs). We conclude by discussing emerging challenges and future directions, including architectural optimizations for performance and scalability, handling of multimodal, multilingual data, and adaptation to novel application domains beyond traditional search paradigms.