Donghyun Kim
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2026
KSAFE-MM: A Multimodal Safety Benchmark via Localized Contextualization for Korean Cultural Risks
Yongwoo Kim | Sojung An | Yunjin Park | Jungwon Yoon | Dujin Lee | HyunBeom Cho | Jaewon Lee | Wonhyuk Lee | Youngchol Kim | JeongYeop Kim | Donghyun Kim
Findings of the Association for Computational Linguistics: EMNLP 2026
Yongwoo Kim | Sojung An | Yunjin Park | Jungwon Yoon | Dujin Lee | HyunBeom Cho | Jaewon Lee | Wonhyuk Lee | Youngchol Kim | JeongYeop Kim | Donghyun Kim
Findings of the Association for Computational Linguistics: EMNLP 2026
Multimodal Large Language Models (MLLMs) exacerbate safety risks by introducing vulnerabilities across multiple modalities, such as language and vision. Current MLLM safety evaluation tools, however, suffer from major limitations: 1) English-centric dataset construction, and 2) a focus on generic risks that are not tied to local cultural contexts. We introduce KSAFE-MM, a benchmark for Korean multimodal safety evaluation that covers both general safety risks and culture-specific vulnerabilities. KSAFE-MM consists of two complementary parts: KSAFE-MM-G evaluates globally shared risks in Korean contexts through linguistic contextualization, which transforms generic safety queries into contextually grounded multimodal samples. In contrast, KSAFE-MM-C targets safety vulnerabilities that are culture-dependent, using localized visual queries drawn from real-world contexts. It pairs these visual queries with jailbreak-style textual queries to cover multimodal safety risks involving cultural visual cues and malicious textual intent. We evaluate 12 state-of-the-art MLLMs on KSAFE-MM and reveal culturally grounded vulnerabilities that translation-based evaluation fails to capture. Notably, jailbreaking strategies substantially amplify attack success rates, with ProgramExecution yielding up to 74.2% ASR compared to 13.4% for standard queries. Furthermore, we identify a systematic trade-off between safety and over-refusal, where models achieving low ASR tend to exhibit excessive refusal behavior on benign queries. These findings highlight the urgent need for culturally grounded safety evaluation beyond English-centric benchmarks.
Talk in Pieces, See in Whole: Disentangled and Hierarchical Representation Learning in Language-based Object Detection
Sojung An | Kwanyong Park | Yong Jae Lee | Donghyun Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Sojung An | Kwanyong Park | Yong Jae Lee | Donghyun Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Vision-language models (VLMs) have advanced multimodal perception, demonstrated by open-vocabulary object detection with simple language queries. State-of-the-art VLMs still struggle to handle complex queries involving descriptive attributes and relational clauses. To address this problem, we propose restructuring linguistic representations according to the hierarchical relations within sentences for language-based object detection. A key insight is the necessity of disentangling textual tokens into core components—objects, attributes, and relations—and subsequently aggregating them into hierarchically structured sentence-level representations. Building on this principle, we introduce the TaSe (Talk in Pieces, See in Whole) framework with three main contributions: (1) a hierarchical synthetic captioning dataset spanning three tiers from category names to descriptive sentences; (2) the three-component disentanglement module guided by a novel disentanglement loss function, transforms text embeddings into subspace compositions; and (3) aggregation disentangled components into hierarchically structured embeddings with the guide of proposed hierarchical objectives. Experimental results under the OmniLabel benchmark show a 24% performance improvement, demonstrating the importance of linguistic compositionality.
VidOmni-Bench: A Benchmark for Fine-Grained Video Understanding via Spatio-Temporal Event Verification across Complexity and Duration
Changbeen Kim | Junwon Chang | Kipyo Kim | Risa Shinoda | Kuniaki Saito | Donghyun Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Changbeen Kim | Junwon Chang | Kipyo Kim | Risa Shinoda | Kuniaki Saito | Donghyun Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
While Video Large Language Models (Video-LLMs) have recently demonstrated strong performance, reliably evaluating their fine-grained video understanding remains challenging. Existing benchmarks often rely on question answering or ground-truth caption matching, where models may succeed through superficial cues and incomplete annotations. To this end, we introduce VidOmni-Bench, a benchmark that requires models to verify whether each event in dense video captions is supported by the video. VidOmni-Bench consists of 500 videos spanning five complexity types and diverse durations from 4 seconds to 90 minutes. After collecting videos along these axes, we use diverse Video-LLMs to generate dense captions and obtain human-verified sentence-level labels, where sentences containing incorrect events serve as hard negatives for evaluation. Our experiments on VidOmni-Bench reveal three key findings: (i) Video-LLMs frequently generate hallucinated descriptions in dense video captioning; (ii) they also struggle as verifiers, failing to reliably detect plausible but incorrect event descriptions; and (iii) model weaknesses vary across video complexity and duration, revealing diverse, model-specific bottlenecks in current Video-LLMs.
Too Many Frames, Not All Useful: Efficient Strategies for Long-Form Video QA
Jongwoo Park | Kanchana Ranasinghe | Kumara Kahatapitiya | Wonjeong Ryu | Donghyun Kim | Michael S Ryoo
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Jongwoo Park | Kanchana Ranasinghe | Kumara Kahatapitiya | Wonjeong Ryu | Donghyun Kim | Michael S Ryoo
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Long-form videos that span across wide temporal intervals are highly information redundant and contain multiple distinct events or entities that are often loosely related. Therefore, when performing long-form video question answering (LVQA), all information necessary to generate a correct response can often be contained within a small subset of frames. Recent literature leverage large language models (LLMs) in LVQA benchmarks, achieving exceptional performance, while relying on vision language models (VLMs) to convert all visual content within videos into natural language. Such VLMs often independently caption a large number of frames uniformly sampled from long videos, which is not efficient and can mostly be redundant. Motivated by this inefficiency, we propose LVNet, a modular and training-free framework featuring a novel Hierarchical Keyframe Selector (HKS) that efficiently selects a minimal set of informative frames tailored to each question. LVNet’s modularity allows easy integration with existing approaches for more efficient LVQA. We achieve state-of-the-art performance among similarly configured models across four benchmark LVQA datasets: EgoSchema, NExT-QA, IntentQA, VideoMME. The code can be found athttps://github.com/jongwoopark7978/LVNet
2024
MATE: Meet At The Embedding - Connecting Images with Long Texts
Young Kyun Jang | Junmo Kang | Yong Jae Lee | Donghyun Kim
Findings of the Association for Computational Linguistics: EMNLP 2024
Young Kyun Jang | Junmo Kang | Yong Jae Lee | Donghyun Kim
Findings of the Association for Computational Linguistics: EMNLP 2024
While advancements in Vision Language Models (VLMs) have significantly improved the alignment of visual and textual data, these models primarily focus on aligning images with short descriptive captions. This focus limits their ability to handle complex text interactions, particularly with longer texts such as lengthy captions or documents, which have not been extensively explored yet. In this paper, we introduce Meet At The Embedding (MATE), a novel approach that combines the capabilities of VLMs with Large Language Models (LLMs) to overcome this challenge without the need for additional image-long text pairs. Specifically, we replace the text encoder of the VLM with a pretrained LLM-based encoder that excels in understanding long texts. To bridge the gap between VLM and LLM, MATE incorporates a projection module that is trained in a multi-stage manner. It starts by aligning the embeddings from the VLM text encoder with those from the LLM using extensive text pairs. This module is then employed to seamlessly align image embeddings closely with LLM embeddings. We propose two new cross-modal retrieval benchmarks to assess the task of connecting images with long texts (lengthy captions / documents). Extensive experimental results demonstrate that MATE effectively connects images with long texts, uncovering diverse semantic relationships.