Wonjoong Kim
2026
Reasoning Structure Matters for Safety Alignment of Reasoning Models
Yeonjun In | Wonjoong Kim | Sangwu Park | Chanyoung Park
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yeonjun In | Wonjoong Kim | Sangwu Park | Chanyoung Park
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large reasoning models (LRMs) achieve strong performance on complex reasoning tasks but often generate harmful responses to malicious user queries. This paper investigates the underlying cause of these safety risks and shows that the issue lies in the reasoning structure itself. Based on this insight, we claim that effective safety alignment can be achieved by altering the reasoning structure. We propose AltTrain, a simple yet effective post-training method that explicitly alters the reasoning structure of LRMs. AltTrain is both practical and generalizable, requiring no complex reinforcement learning (RL) training or reward design—only supervised fine-tuning (SFT) with a lightweight 1K training examples. Experiments across LRM backbones and model sizes demon strate strong safety alignment, along with robust generalization across reasoning, QA, summarization, and multilingual setting.
2025
SIMPLOT: Enhancing Chart Question Answering by Distilling Essentials
Wonjoong Kim | Sangwu Park | Yeonjun In | Seokwon Han | Chanyoung Park
Findings of the Association for Computational Linguistics: NAACL 2025
Wonjoong Kim | Sangwu Park | Yeonjun In | Seokwon Han | Chanyoung Park
Findings of the Association for Computational Linguistics: NAACL 2025
Recently, interpreting complex charts with logical reasoning has emerged as challenges due to the development of vision-language models. A prior state-of-the-art (SOTA) model has presented an end-to-end method that leverages the vision-language model to convert charts into table format utilizing Large Language Model (LLM) for reasoning. However, unlike natural images, charts contain a mix of essential and irrelevant information required for chart reasoning, and we discover that this characteristic can lower the performance of chart-to-table extraction. In this paper, we introduce SIMPLOT, a method designed to extract only the elements necessary for chart reasoning. The proposed method involves two steps: 1) training to mimic a simple plot that contains only the essential information from a complex chart for table extraction, followed by 2) performing reasoning based on the table. Our model enables accurate chart reasoning without the need for additional annotations or datasets, and its effectiveness is demonstrated through various experiments.
Is Safety Standard Same for Everyone? User-Specific Safety Evaluation of Large Language Models
Yeonjun In | Wonjoong Kim | Kanghoon Yoon | Sungchul Kim | Mehrab Tanjim | Sangwu Park | Kibum Kim | Chanyoung Park
Findings of the Association for Computational Linguistics: EMNLP 2025
Yeonjun In | Wonjoong Kim | Kanghoon Yoon | Sungchul Kim | Mehrab Tanjim | Sangwu Park | Kibum Kim | Chanyoung Park
Findings of the Association for Computational Linguistics: EMNLP 2025
As the use of large language model (LLM) agents continues to grow, their safety vulnerabilities have become increasingly evident. Extensive benchmarks evaluate various aspects of LLM safety by defining the safety relying heavily on general standards, overlooking user-specific standards. However, safety standards for LLM may vary based on a user-specific profiles rather than being universally consistent across all users. This raises a critical research question: Do LLM agents act safely when considering user-specific safety standards? Despite its importance for safe LLM use, no benchmark datasets currently exist to evaluate the user-specific safety of LLMs. To address this gap, we introduce U-SafeBench, a benchmark designed to assess user-specific aspect of LLM safety. Our evaluation of 20 widely used LLMs reveals current LLMs fail to act safely when considering user-specific safety standards, marking a new discovery in this field. To address this vulnerability, we propose a simple remedy based on chain-of-thought, demonstrating its effectiveness in improving user-specific safety.