Changdae Oh
2026
VAUQ: Vision-Aware Uncertainty Quantification for LVLM Self-Evaluation
Seongheon Park | Changdae Oh | Hyeong Kyu Choi | Sean Du | Sharon Li
Findings of the Association for Computational Linguistics: ACL 2026
Seongheon Park | Changdae Oh | Hyeong Kyu Choi | Sean Du | Sharon Li
Findings of the Association for Computational Linguistics: ACL 2026
Large Vision-Language Models (LVLMs) frequently hallucinate, limiting their safe deployment in real-world applications. Existing LLM self-evaluation methods rely on a model’s ability to estimate the correctness of its own outputs, which can improve deployment reliability; however, they depend heavily on language priors and are therefore ill-suited for evaluating vision-conditioned predictions. We propose VAUQ, a vision-aware uncertainty quantification framework for LVLM self-evaluation that explicitly measures how strongly a model’s output depends on visual evidence. VAUQ introduces the Image-Information Score (IS), which captures the reduction in predictive uncertainty attributable to visual input, and an unsupervised core-region masking strategy that amplifies the influence of salient regions. Combining predictive entropy with this core-masked IS yields a training-free scoring function that reliably reflects answer correctness. Comprehensive experiments show that VAUQ consistently outperforms existing self-evaluation methods across multiple datasets.
Uncertainty Quantification in LLM Agents: Foundations, Emerging Challenges, and Opportunities
Changdae Oh | Seongheon Park | To Eun Kim | Jiatong Li | Wendi Li | Samuel Yeh | Sean Du | Hamed Hassani | Paul Bogdan | Dawn Song | Sharon Li
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Changdae Oh | Seongheon Park | To Eun Kim | Jiatong Li | Wendi Li | Samuel Yeh | Sean Du | Hamed Hassani | Paul Bogdan | Dawn Song | Sharon Li
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Uncertainty quantification (UQ) for large language models (LLMs) is a key building block for safety guardrails of daily LLM applications. Yet, even as LLM agents are increasingly deployed in highly complex tasks, most UQ research still centers on single-turn question-answering. We argue that UQ research must shift to realistic settings with interactive agents, and that a new principled framework for agent UQ is needed. This paper presents three pillars to build a solid ground for future agent UQ research: (1. Foundations) We present the first general formulation of agent UQ that subsumes broad classes of existing UQ setups; (2. Challenges) We identify four technical challenges specifically tied to agentic setups—selection of uncertainty estimator, uncertainty of heterogeneous entities, modeling uncertainty dynamics in interactive systems, and lack of fine-grained benchmarks—with numerical analysis on a real-world agent benchmark, 𝜏2-bench; (3. Future Directions) We conclude with noting on the practical implications of agent UQ and remaining open problems as forward-looking discussion for future explorations.
2024
Mitigating the Linguistic Gap with Phonemic Representations for Robust Cross-lingual Transfer
Haeji Jung | Changdae Oh | Jooeon Kang | Jimin Sohn | Kyungwoo Song | Jinkyu Kim | David R Mortensen
Proceedings of the Fourth Workshop on Multilingual Representation Learning (MRL 2024)
Haeji Jung | Changdae Oh | Jooeon Kang | Jimin Sohn | Kyungwoo Song | Jinkyu Kim | David R Mortensen
Proceedings of the Fourth Workshop on Multilingual Representation Learning (MRL 2024)
Approaches to improving multilingual language understanding often struggle with significant performance gaps between high-resource and low-resource languages. While there are efforts to align the languages in a single latent space to mitigate such gaps, how different input-level representations influence such gaps has not been investigated, particularly with phonemic inputs. We hypothesize that the performance gaps are affected by representation discrepancies between those languages, and revisit the use of phonemic representations as a means to mitigate these discrepancies.To demonstrate the effectiveness of phonemic representations, we present experiments on three representative cross-lingual tasks on 12 languages in total. The results show that phonemic representations exhibit higher similarities between languages compared to orthographic representations, and it consistently outperforms grapheme-based baseline model on languages that are relatively low-resourced.We present quantitative evidence from three cross-lingual tasks that demonstrate the effectiveness of phonemic representations, and it is further justified by a theoretical analysis of the cross-lingual performance gap.