Junyeob Kim
Author directory2026
Can Omni-models Imagine the Future? A Diagnostic Benchmark for Multimodal World Modeling
Junyeob Kim | Jihwan Kim | Minha Jhang | Sungwook Jeon | Hwiyeol Jo | Jeonghoon Kim | Sang-goo Lee | Joosung Lee
Findings of the Association for Computational Linguistics: EMNLP 2026
Junyeob Kim | Jihwan Kim | Minha Jhang | Sungwook Jeon | Hwiyeol Jo | Jeonghoon Kim | Sang-goo Lee | Joosung Lee
Findings of the Association for Computational Linguistics: EMNLP 2026
Recent progress in Omni-models has yielded strong performance on benchmarks focused on static observations. However, their ability to maintain spatiotemporal continuity when predicting coherent future states from previous context remains underexplored. We address this by formulating Next Scene Prediction (NSP) as a diagnostic task for assessing multimodal near-future state prediction, requiring models to anticipate the immediate future from a given context. We introduce OmniNSP, a benchmark evaluating causal and cross-modal coherence across physical, logical, and social dynamics. Unlike prior tasks that often rely on textual or discriminative proxies, OmniNSP asks models to express predicted future states through text-mediated visual and speech synthesis. Our analysis shows that current Omni-models can produce plausible textual forecasts while still failing to preserve future-state consistency in generated outputs. A frozen-generator control substantially narrows cross-model visual-consistency gaps, attributing much of the original system-level difference to model-specific realization stacks rather than textual foresight alone. A modality-input ablation further shows that audio provides complementary predictive cues beyond vision, with the largest gains for logical transitions and contexts with informative speech. These results position OmniNSP as a diagnostic of both near-future prediction and the preservation of predicted state through multimodal realization.
Think Just Enough: Leveraging Self-Assessed Confidence for Adaptive Reasoning in Language Models
Junyeob Kim | Sang-goo Lee | Taeuk Kim
Findings of the Association for Computational Linguistics: EACL 2026
Junyeob Kim | Sang-goo Lee | Taeuk Kim
Findings of the Association for Computational Linguistics: EACL 2026
Recent reinforcement learning (RL)-trained language models have demonstrated strong performance on complex reasoning tasks by producing long and detailed reasoning traces. However, despite these advancements, they often struggle with finding the right balance in reasoning length: some terminate prematurely before reaching a correct answer (underthinking), while others continue reasoning beyond necessity, leading to inefficiency or even degraded accuracy (overthinking).To address these challenges, we propose a method for optimizing reasoning length via self-assessed confidence. By prompting the model to evaluate its own confidence at intermediate reasoning steps, we enable dynamic stopping once sufficient reasoning is achieved.Experiments across multiple reasoning benchmarks show that our approach improves computational efficiency without compromising answer quality. Furthermore, we find that confidence estimates from RL-trained reasoning models are more reliable than those from standard LLMs, making it a valuable internal signal for controlling reasoning depth.
A Composable Evaluation System for Reproducible Omni-Modal Foundation Model Evaluation
Hodong Lee | Sanghee Park | Dohoon Ryu | Jungwhan Kim | Junyeob Kim | Soyoon Kim | Geewook Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Hodong Lee | Sanghee Park | Dohoon Ryu | Jungwhan Kim | Junyeob Kim | Soyoon Kim | Geewook Kim
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Building an omni-modal foundation model means evaluating it across text, image, video, and audio. Excellent evaluation toolkits exist for each modality, but their inference engines, prompt conventions, and metric implementations are mutually incompatible, so practitioners end up maintaining separate environments for every toolchain and still struggle to compare results across them. OmniEvaluator grew out of this need in our own model development: rather than reimplementing benchmarks, it connects existing inference engines and curated evaluation libraries at a higher level, exposing four inference backends, four evaluation frameworks, and over a thousand benchmarks through a single interface. Every run is recorded as an artifact capturing the full configuration for exact reproduction, and results flow into a shared dashboard for cross-model comparison. A federated mode shares GPU inference servers across concurrent evaluations, and a built-in verifier, small enough to run on CPU, keeps its score stable across engines and prompts where rule-based scoring fluctuates under configuration mismatch, matching cost-efficient commercial LLM judges without their recurring API cost. The system, demo video, and dashboard are publicly available. (https://github.com/naver-ai/omni-evaluator, https://www.youtube.com/watch?v=4Z5VZZWyXqY, https://omni-evaluator.info)
2024
Adaptive Contrastive Decoding in Retrieval-Augmented Generation for Handling Noisy Contexts
Youna Kim | Hyuhng Joon Kim | Cheonbok Park | Choonghyun Park | Hyunsoo Cho | Junyeob Kim | Kang Min Yoo | Sang-goo Lee | Taeuk Kim
Findings of the Association for Computational Linguistics: EMNLP 2024
Youna Kim | Hyuhng Joon Kim | Cheonbok Park | Choonghyun Park | Hyunsoo Cho | Junyeob Kim | Kang Min Yoo | Sang-goo Lee | Taeuk Kim
Findings of the Association for Computational Linguistics: EMNLP 2024
When using large language models (LLMs) in knowledge-intensive tasks, such as open-domain question answering, external context can bridge the gap between external knowledge and the LLMs’ parametric knowledge.Recent research has been developed to amplify contextual knowledge over the parametric knowledge of LLMs with contrastive decoding approaches.While these approaches could yield truthful responses when relevant context is provided, they are prone to vulnerabilities when faced with noisy contexts.We extend the scope of previous studies to encompass noisy contexts and propose adaptive contrastive decoding (ACD) to leverage contextual influence effectively.ACD demonstrates improvements in open-domain question answering tasks compared to baselines, especially in robustness by remaining undistracted by noisy contexts in retrieval-augmented generation.
Aligning Language Models to Explicitly Handle Ambiguity
Hyuhng Joon Kim | Youna Kim | Cheonbok Park | Junyeob Kim | Choonghyun Park | Kang Min Yoo | Sang-goo Lee | Taeuk Kim
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Hyuhng Joon Kim | Youna Kim | Cheonbok Park | Junyeob Kim | Choonghyun Park | Kang Min Yoo | Sang-goo Lee | Taeuk Kim
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
In interactions between users and language model agents, user utterances frequently exhibit ellipsis (omission of words or phrases) or imprecision (lack of exactness) to prioritize efficiency. This can lead to varying interpretations of the same input based on different assumptions or background knowledge. It is thus crucial for agents to adeptly handle the inherent ambiguity in queries to ensure reliability. However, even state-of-the-art large language models (LLMs) still face challenges in such scenarios, primarily due to the following hurdles: (1) LLMs are not explicitly trained to deal with ambiguous utterances; (2) the degree of ambiguity perceived by the LLMs may vary depending on the possessed knowledge. To address these issues, we propose Alignment with Perceived Ambiguity (APA), a novel pipeline that aligns LLMs to manage ambiguous queries by leveraging their own assessment of ambiguity (i.e., perceived ambiguity). Experimental results on question-answering datasets demonstrate that APA empowers LLMs to explicitly detect and manage ambiguous queries while retaining the ability to answer clear questions. Furthermore, our finding proves that APA excels beyond training with gold-standard labels, especially in out-of-distribution scenarios. The data and code are available at https://github.com/heyjoonkim/APA.
2023
Probing Out-of-Distribution Robustness of Language Models with Parameter-Efficient Transfer Learning
Hyunsoo Cho | Choonghyun Park | Junyeob Kim | Hyuhng Joon Kim | Kang Min Yoo | Sang-goo Lee
Proceedings of the 12th Joint Conference on Lexical and Computational Semantics (*SEM 2023)
Hyunsoo Cho | Choonghyun Park | Junyeob Kim | Hyuhng Joon Kim | Kang Min Yoo | Sang-goo Lee
Proceedings of the 12th Joint Conference on Lexical and Computational Semantics (*SEM 2023)
As the size of the pre-trained language model (PLM) continues to increase, numerous parameter-efficient transfer learning methods have been proposed recently to compensate for the high cost of fine-tuning. While large PLMs and various PETL methods have achieved impressive results on various benchmarks, it is uncertain whether they can effectively handle inputs that have been distributionally shifted. In this study, we systematically explore how the ability to detect out-of-distribution (OOD) changes as the size of the PLM grows or the transfer methods are altered. Specifically, we evaluated various PETL techniques, including fine-tuning, Adapter, LoRA, and prefix-tuning, with various language models with different scales.
Universal Domain Adaptation for Robust Handling of Distributional Shifts in NLP
Hyuhng Kim | Hyunsoo Cho | Sang-Woo Lee | Junyeob Kim | Choonghyun Park | Sang-goo Lee | Kang Yoo | Taeuk Kim
Findings of the Association for Computational Linguistics: EMNLP 2023
Hyuhng Kim | Hyunsoo Cho | Sang-Woo Lee | Junyeob Kim | Choonghyun Park | Sang-goo Lee | Kang Yoo | Taeuk Kim
Findings of the Association for Computational Linguistics: EMNLP 2023
When deploying machine learning systems to the wild, it is highly desirable for them to effectively leverage prior knowledge to the unfamiliar domain while also firing alarms to anomalous inputs. In order to address these requirements, Universal Domain Adaptation (UniDA) has emerged as a novel research area in computer vision, focusing on achieving both adaptation ability and robustness (i.e., the ability to detect out-of-distribution samples). While UniDA has led significant progress in computer vision, its application on language input still needs to be explored despite its feasibility. In this paper, we propose a comprehensive benchmark for natural language that offers thorough viewpoints of the model’s generalizability and robustness. Our benchmark encompasses multiple datasets with varying difficulty levels and characteristics, including temporal shifts and diverse domains. On top of our testbed, we validate existing UniDA methods from computer vision and state-of-the-art domain adaptation techniques from NLP literature, yielding valuable findings: We observe that UniDA methods originally designed for image input can be effectively transferred to the natural language domain while also underscoring the effect of adaptation difficulty in determining the model’s performance.
2022
Ground-Truth Labels Matter: A Deeper Look into Input-Label Demonstrations
Kang Min Yoo | Junyeob Kim | Hyuhng Joon Kim | Hyunsoo Cho | Hwiyeol Jo | Sang-Woo Lee | Sang-goo Lee | Taeuk Kim
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing
Kang Min Yoo | Junyeob Kim | Hyuhng Joon Kim | Hyunsoo Cho | Hwiyeol Jo | Sang-Woo Lee | Sang-goo Lee | Taeuk Kim
Proceedings of the 2022 Conference on Empirical Methods in Natural Language Processing
Despite recent explosion of interests in in-context learning, the underlying mechanism and the precise impact of the quality of demonstrations remain elusive.Intuitively, ground-truth labels should have as much impact in in-context learning (ICL) as supervised learning, but recent work reported that the input-label correspondence is significantly less important than previously thought.Intrigued by this counter-intuitive observation, we re-examine the importance of ground-truth labels in in-context learning.With the introduction of two novel metrics, namely Label-Correctness Sensitivity and Ground-truth Label Effect Ratio (GLER), we were able to conduct quantifiable analysis on the impact of ground-truth label demonstrations.Through extensive analyses, we find that the correct input-label mappings can have varying impacts on the downstream in-context learning performances, depending on the experimental configuration.Through additional studies, we identify key components, such as the verbosity of prompt templates and the language model size, as the controlling factor to achieve more noise-resilient ICL.