Woojin Lee
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2026
SolidCoder: Bridging the Mental-Reality Gap in LLM Code Generation through Concrete Execution
Woojin Lee | Jin-Xia Huang
Findings of the Association for Computational Linguistics: ACL 2026
Woojin Lee | Jin-Xia Huang
Findings of the Association for Computational Linguistics: ACL 2026
State-of-the-art code generation frameworks rely on mental simulation, where LLMs internally trace execution to verify correctness. We expose a fundamental limitation: the Mental-Reality Gap—where models hallucinate execution traces and confidently validate buggy code. This gap manifests along two orthogonal dimensions: the Specification Gap (overlooking edge cases during planning) and the Verification Gap (hallucinating correct behavior for flawed code). We propose SolidCoder with a simple principle: don’t imagine—execute. The S.O.L.I.D. architecture addresses both dimensions by forcing edge-case awareness before algorithm design and replacing imagined traces with sandboxed execution using property-based oracles. With GPT-4o, SolidCoder achieves state-of-the-art pass@1 performance: 95.7% on HumanEval (+0.6%p), 77.0% on CodeContests (+4.3%p), and 26.7% on APPS (+3.4%p). Ablation reveals that edge-case awareness provides the largest individual gain, while execution grounding catches categorically different errors that specification improvements cannot address. These gains generalize to RL post-trained models, validating that bridging both gap dimensions is essential for robust code synthesis. We release our code and framework to facilitate future research.
YouRA: A Persistent-State Architecture for Evidence-Traceable Autonomous Research Agents
Yoonkyu Woo | Woojin Lee | Jin-Xia Huang
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers)
Yoonkyu Woo | Woojin Lee | Jin-Xia Huang
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 2: Short Papers)
End-to-end research agents can now produce complete scientific papers, yet manuscript claims often diverge from executed experiments. This gap is structural: research state, failure histories, and claim–evidence alignment are not maintained as persistent, verifiable state across long-horizon pipelines. We present YouRA (Your Research Agent), an architecture for stateful, evidence-traceable autonomous research. YouRA preserves research state, execution evidence, and failure history across the research trajectory by integrating three components: a Verification State Architecture (VSA) that tracks hypotheses, gates, and evidence pointers; an Independent Controller that turns state and reflection records into lifecycle, recovery, and debate/review control while separating control from execution; and Stateful Reflection that logs failures as structured lessons and routes recovery through bounded repair, redesign, or reset. On MLR-Bench’s predefined ten-task end-to-end subset, YouRA improves over both MLR-Agent and AI Scientist V2 on scalar Overall across all three matched backbones. An automated diagnostic using MLR-Bench’s hallucination taxonomy reports intersection/union counts for four fact-based failure types, and data-provenance diagnostic shows more real-data-based outputs. Ablating each of the four components (the VSA, the Independent Controller, MCP tool access, and reflection-guided recovery) supports their separable contributions. Removing either core-state component drops YouRA below the full system. Code: https://github.com/PrayPrey/Your-Research-Agent.
MisconceptDialogue: Evaluation Criteria Shape Measured Success in LLM Math Tutoring
Woojin Lee | Yoonkyu Woo | Jinah Kim | Hyeok-Min Gwon | Jin-Xia Huang
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Woojin Lee | Yoonkyu Woo | Jinah Kim | Hyeok-Min Gwon | Jin-Xia Huang
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models are increasingly used as math tutors, raising two questions: can a single LLM detect a student’s error, diagnose the underlying misconception, and remediate it through multi-turn dialogue—and can we trust the numbers that report how well it does? We address both with MisconceptDialogue, a fully automated framework that runs the full pipeline on five open-weight LLM tutors (7B–14B) interacting with LLM-simulated students over 5,000+ dialogues—a deliberately simulated protocol (paired conditions, a wrong-diagnosis control unsafe with real learners, scale) whose results do not establish real-student learning. On measurement, our headline finding is uncomfortable for the field: benchmark-style exact-match scoring common in standard math NLP—a lower-bound stress test—reports 42.1% measured Remediation Success Rate on identical dialogues where a human-calibrated LLM-as-judge reports 81.3%, a 39.2 percentage-point spread larger than the combined effects of tutor model, teaching strategy, and supplied diagnostic information. This is not a single-judge artifact: four independent LLM judges and 200 human annotations converge to within a few points (κ up to 0.91). On capability, the verdict is equally striking: the score barely changes whether we tell the tutor the student’s actual misconception or a deliberately swapped one—under the tested diagnosis-presentation format, these tutors show little evidence of reliably conditioning on the diagnostic information they are handed. For LLM tutoring evaluation to mature, multi-criterion scoring with multi-judge convergence and human anchoring should become standard practice—and the measurement question deserves as much scrutiny as the capability question it claims to answer.
2025
Multilingual, Not Multicultural: Uncovering the Cultural Empathy Gap in LLMs through a Comparative Empathetic Dialogue Benchmark
Woojin Lee | Yujin Sim | Hongjin Kim | Harksoo Kim
Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Woojin Lee | Yujin Sim | Hongjin Kim | Harksoo Kim
Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Large Language Models (LLMs) demonstrate remarkable multilingual capabilities, yet it remains unclear whether they are truly multicultural. Do they merely process different languages, or can they genuinely comprehend the unique cultural contexts embedded within them? This study investigates this critical question by examining whether LLM’s perception of emotion and empathy differs across linguistic and cultural boundaries. To facilitate this, we introduce the Korean Empathetic Dialogues (KoED), a benchmark extending the English-based EmpatheticDialogues (ED) dataset. Moving beyond direct translation, we meticulously reconstructed dialogues specifically selected for their potential for cultural adaptation, aligning them with Korean emotional nuances and incorporating key cultural concepts like ‘jeong’ and ‘han’ that lack direct English equivalents. Our cross-cultural evaluation of leading multilingual LLMs reveals a significant “cultural empathy gap”: models consistently underperform on KoED compared to ED, struggling especially with uniquely Korean emotional expressions. Notably, the Korean-centric model, EXAONE, exhibits significantly higher cultural appropriateness. This result provides compelling evidence that aligns with the “data provenance effect”, suggesting that the cultural alignment of pre-training data is a critical factor for genuine empathetic communication. These findings demonstrate that current LLMs have cultural blind spots and underscore the necessity of benchmarks like KoED to move beyond simple linguistic fluency towards truly culturally adaptive AI systems.
Do Large Language Models Have “Emotion Neurons”? Investigating the Existence and Role
Jaewook Lee | Woojin Lee | Oh-Woog Kwon | Harksoo Kim
Findings of the Association for Computational Linguistics: ACL 2025
Jaewook Lee | Woojin Lee | Oh-Woog Kwon | Harksoo Kim
Findings of the Association for Computational Linguistics: ACL 2025
This study comprehensively explores whether there actually exist “emotion neurons” within large language models (LLMs) that selectively process and express certain emotions, and what functional role they play. Drawing on the representative emotion theory of the six basic emotions, we focus on six core emotions. Using synthetic dialogue data labeled with emotions, we identified sets of neurons that exhibit consistent activation patterns for each emotion. As a result, we confirmed that principal neurons handling emotion information do indeed exist within the model, forming distinct groups for each emotion, and that their distribution varies with model size and architectural depth. We then validated the functional significance of these emotion neurons by analyzing whether the prediction accuracy for a specific emotion significantly decreases when those neurons are artificially removed. We observed that in some emotions, the accuracy drops sharply upon neuron removal, while in others, the model’s performance largely remains intact or even improves, presumably due to overlapping and complementary mechanisms among neurons. Furthermore, by examining how prediction accuracy changes depending on which layer range and at what proportion the emotion neurons are masked, we revealed that emotion information is processed in a multilayered and complex manner within the model.
2024
Analyzing Key Factors Influencing Emotion Prediction Performance of VLLMs in Conversational Contexts
Jaewook Lee | Yeajin Jang | Hongjin Kim | Woojin Lee | Harksoo Kim
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Jaewook Lee | Yeajin Jang | Hongjin Kim | Woojin Lee | Harksoo Kim
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Emotional intelligence (EI) in artificial intelligence (AI), which refers to the ability of an AI to understand and respond appropriately to human emotions, has emerged as a crucial research topic. Recent studies have shown that large language models (LLMs) and vision large language models (VLLMs) possess EI and the ability to understand emotional stimuli in the form of text and images, respectively. However, factors influencing the emotion prediction performance of VLLMs in real-world conversational contexts have not been sufficiently explored. This study aims to analyze the key elements affecting the emotion prediction performance of VLLMs in conversational contexts systematically. To achieve this, we reconstructed the MELD dataset, which is based on the popular TV series Friends, and conducted experiments through three sub-tasks: overall emotion tone prediction, character emotion prediction, and contextually appropriate emotion expression selection. We evaluated the performance differences based on various model architectures (e.g., image encoders, modality alignment, and LLMs) and image scopes (e.g., entire scene, person, and facial expression). In addition, we investigated the impact of providing persona information on the emotion prediction performance of the models and analyzed how personality traits and speaking styles influenced the emotion prediction process. We conducted an in-depth analysis of the impact of various other factors, such as gender and regional biases, on the emotion prediction performance of VLLMs. The results revealed that these factors significantly influenced the model performance.