Geon Lee
Author directory2026
Hybrid-Vector Retrieval for Visually Rich Documents: Combining Single-Vector Efficiency and Multi-Vector Accuracy
Juyeon Kim | Geon Lee | Dongwon Choi | Taeuk Kim | Kijung Shin
Findings of the Association for Computational Linguistics: ACL 2026
Juyeon Kim | Geon Lee | Dongwon Choi | Taeuk Kim | Kijung Shin
Findings of the Association for Computational Linguistics: ACL 2026
Retrieval over visually rich documents is essential for tasks such as legal discovery, scientific search, and enterprise knowledge management. Existing approaches fall into two paradigms: single-vector retrieval, which is efficient but coarse, and multi-vector retrieval, which is accurate but computationally expensive. To address this trade-off, we propose HEAVEN, a plug-and-play two-stage hybrid-vector framework. In the first stage, HEAVEN efficiently retrieves candidate pages using a single-vector method over Visually-Summarized Pages (VS-Pages), which assemble representative visual layouts from multiple pages. In the second stage, it reranks candidates with a multi-vector method while filtering query tokens by linguistic importance to reduce redundant computations. To evaluate retrieval systems under realistic conditions, we also introduce ViMDoc, a benchmark for visually rich, multi-document, and long-document retrieval. Across four benchmarks, HEAVEN attains 99.87% of the Recall@1 performance of multi-vector models on average while reducing per-query computation by 99.82%, achieving efficiency and accuracy. Our code and datasets are available at: https://github.com/juyeonnn/HEAVEN
Zero-Shot Tabular Learning via Hypergraph Reasoning with LLMs
Geon Lee | Kyungho Kim | Dongwon Choi | Juyeon Kim | Shinhwan Kang | Kijung Shin
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Geon Lee | Kyungho Kim | Dongwon Choi | Juyeon Kim | Shinhwan Kang | Kijung Shin
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Tabular data are prevalent across diverse domains such as healthcare and finance. Zero-shot tabular learning aims to make predictions without labeled data. However, existing LLM-based approaches rely on row-wise prompting, resulting in high inference cost and limited use of inter-row dependencies. In this work, we propose TabHGR+, an efficient relation-aware zero-shot framework for tabular data that leverages LLM-generated rules to label and group rows. Specifically, based on column and task descriptions, we use LLMs to generate rules that assign weak labels to all rows. To refine these noisy weak labels, we construct a hypergraph by grouping semantically related rows using LLM-generated rules and perform hypergraph-based label propagation. Lastly, we further enhance the LLM-generated hypergraph for propagation, which is potentially suboptimal, by assigning label-adaptive weights to hyperedges. By requiring only a constant number of LLM calls independent of dataset size, TabHGR+ substantially reduces inference cost while achieving higher classification accuracy than zero-shot and strong few-shot baselines.