arXiv Computation and Language

Chunk Recomputation under Real Document Revisions: Measuring Update Cost and Retrieval Quality of Fixed, Recursive, and Content-Defined Chunking

The paper evaluates how different chunking strategies—fixed-size, recursive paragraph-first, and content-defined—affect the cost of updating embeddings when Wikipedia documents are revised. Using 120 pairs of Chinese and English revisions, the authors find that fixed-size chunking requires the most recomputation (57‑68 % of the workload), while recursive and content-defined chunking need less (38‑56 % and 43‑54 % respectively). Despite these differences, evidence recall under a 2048‑token retrieval budget varies by less than two percentage points across methods and languages.

arXiv AI
Aug 19

DEPT: Document Embedding Preservation Tuning for Unified Query Expansion and Retrieval

The paper introduces DEPT, a method that trains a single decoder-only large language model to both expand queries and encode documents for retrieval. By preserving document embeddings close to their initial cached values while allowing gradients to flow through the generator, DEPT stabilizes retrieval targets and enables efficient index reuse and online hard‑negative mining. Experiments on the BEIR benchmark with Qwen3‑4B‑Instruct‑2507 and LLaMA‑3.2‑3B‑Instruct show that DEPT outperforms training‑free, independently trained, and staged unified baselines, with ablations confirming the benefits of preservation, whitening, end‑to‑end expansion training, and online negatives.

By Jingyuan Wang, Richong Zhang, Zhijie Nie, Mingxin Li, Yanzhao Zhang
arXiv Computer Vision
Sep 22

Document Retrieval-Aware Chunking (D-RAC): Universal Retrieval-Aware Ingestion of Enterprise Documents via PDF Normalization and Multimodal Markdown Conversion

arXiv:2609.24220v1 Announce Type: new Abstract: Retrieval-Augmented Generation (RAG) systems over enterprise knowledge bases must ingest heterogeneous document formats -- PDFs, Word documents, presen...

By Uday Allu (AI Research Team Yellow.ai), Abhivanth Sivaprakash (AI Research Team Yellow.ai), Pratik Singh (AI Research Team Yellow.ai), Aman Manocha (AI Research Team Yellow.ai)
arXiv AI
Aug 24

RAG Deserves an Index: Why Ingest-Time Compilation Beats Query-Time Interpretation

The paper argues that retrieval‑augmented question‑answering systems should perform semantic compilation at ingest time rather than re‑deriving meaning at query time. By building a maintained structure—incrementally updated embeddings and validated atomic claims—read operations become far cheaper, with experimental results showing higher accuracy and lower token usage compared to traditional chunk‑based retrieval. The authors present two proofs: cheaper incremental updates and superior performance on broadcast‑interview transcripts, suggesting a new systems agenda for compilation and read planning.

By Kyle Wild, Yusuke Takahashi, Asako Uraki
arXiv AI
Oct 15

Budgeted KV-Cache Repair for Evolving Contexts

arXiv:2610.17338v1 Announce Type: new Abstract: Language-model agents revise their working context as information becomes obsolete, but deleting text does not erase its influence on cached computatio...

By Han Yu, Wenhui Zhu, Jincheng Cao, Rui Cai, Yuanda Xu, Zhengze Zhou, Xiwen Chen, Hao Wang, Xuanzhao Dong, Han Shi, Menglin Zhou, Shayan Mohajer Hamidi, Lin Su, Mina Razghandi, Sayan Ghosh, Qing Lan, Rohit Jain, Alborz Geramifard
arXiv AI
Oct 12

PRIME: Pre-Retrieval Index Modeling Enhancement for Structured Document Retrieval-Real

PRIME introduces an index-side optimization framework for structured document retrieval, comprising a Semantic Restructuring track that converts long documents into dense, structured sections and a Metadata Synthesis & Hierarchical Retrieval track that extracts semantic anchors and heading structures for efficient coarse-to-fine retrieval. The approach reduces embedding computation by 45.8× and index vector count by 22.4× while maintaining retrieval quality comparable to structure-aware chunking. In full deployment, Semantic Restructuring improves Answer‑F1 by 13.7%, and the study identifies qualitative regimes that influence when index-side optimization is beneficial or detrimental, noting that strong rerankers neutralize these effects.

By Cheuk Hei Chung, Li Liu
arXiv Computation and Language
Oct 12

KV-Repurpose: A Testbed for Evaluating Non-Prefix KV-Cache Reuse

KV-Repurpose is an open‑source, vLLM‑based system that enables segment‑wise KV‑cache reuse beyond exact prompt prefixes in large language model serving. It integrates cache‑aware segment scheduling, prompt construction, capacity management, workload generation, and runtime monitoring to evaluate non‑prefix KV‑cache reuse. Experiments show that naive segment reuse maintains output quality for single‑document QA and summarization, while significantly improving cache hit rates and reducing time‑to‑first‑token compared to prefix caching, especially under Zipfian RAG‑style workloads.

By Taiga Ikeda, Daisuke Miyashita, Jun Deguchi