Hi! or "Annyeonghaseyo!" I am an incoming Ph.D. student in Computer Science at the University of Cambridge, advised by Prof. Andreas Vlachos. Prior to this, I received M.S. in Computer Science & Engineering at Korea University as a member of DMIS Lab, advised by Prof. Jaewoo Kang, and received B.S. in Linguistics and Computer Science from the same institution. I worked as a researcher intern at Aigen Science Inc., Nara-Information, and Song Lab (hosted by Prof. Sanghoun Song).
My research covers the broad field of natural language processing, with a primary focus on driving Post-Training innovations through Mechanistic Interpretability. I trace the internal computations of LLMs to design interpretable alignment techniques for Safety, Knowledge Editing, and Reasoning. Moving forward, I envision devising fine-grained post-training methods that resolve localized breakdowns without robustness trade-offs. Beyond general models, I also apply RAG, RL techniques and these alignment insights to Biomedical, Molecular LMs.
You can find my CV in here.
[jɛin bɑk]
Selected Publications
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[Under Review] Thinking Sparks!: Emergent Attention Heads in Reasoning Models During Post Training
Yein Park, Minbyul Jeong, Jaewoo Kang
[ACL 2026 Findings] ToxReason: A Benchmark for Mechanistic Chemical Toxicity Reasoning via Adverse Outcome Pathway
Jueon Park, WonJune Jang, Chanhwi Kim, Yein Park, Jaewoo Kang
[ICLR 2026] ASGuard: Activation-Scaling Guard to Mitigate Targeted Jailbreaking Attack
Yein Park, Jungwoo Park, Jaewoo Kang
[IEEE BIBM 2025] CoTox: Chain-of-Thought-Based Molecular Toxicity Reasoning and Prediction
Jueon Park, Yein Park, Minju Song, Soyon Park, Donghyeon Lee, Seungheun Baek, Jaewoo Kang
[🥇1st Rank] DMIS Lab at MedHopQA-2025: Ensemble Multi-Retrieval Methodologies with Reasoning Language Model Decision
Jongmyung Jung†, Hyeongsoon Hwang†, Yein Park†, Minju Song, Jaehoon Yoon, Hyeon Hwang, Sanghoon Lee, Jiwoong Sohn, Jaewoo Kang
[EMNLP 2025 Findings] Assessing LLM Reasoning Steps via Principal Knowledge Grounding
Hyeon Hwang, Yewon Cho, Chanwoong Yoon, Yein Park, Minju Song, Kyungjae Lee, Gangwoo Kim, Jaewoo Kang
[ACL 2025] Does Time Have Its Place? Temporal Heads: Where Language Models Recall Time-specific Information
Yein Park, Chanwoong Yoon, Jungwoo Park, Minbyul Jeong, Jaewoo Kang
[ICLR 2025] ChroKnowledge: Unveiling Chronological Knowledge of Language Models in Multiple Domains
Yein Park, Chanwoong Yoon, Jungwoo Park, Donghyeon Lee, Minbyul Jeong, Jaewoo Kang
[NAACL 2025] Rationale-Guided Retrieval Augmented Generation for Medical Question Answering
Jiwoong Sohn, Yein Park, Chanwoong Yoon, Sihyeon Park, Hyeon Hwang, Mujeen Sung, Hyunjae Kim, Jaewoo Kang
Academic Experience
(advisor: Prof. Andreas Vlachos)
(supervisor: Prof. Ludwig Schmidt at Stanford University)
Data Mining & Information Systems Lab (advisor: Prof. Jaewoo Kang)
(advisor: Prof. Seok-Hoon You)
Work Experience
Aigen Science Inc.
[Sep 2025 - May 2026] @South Korea
Research Intern Advisor: Sanghoon Lee
- Developed on-premise clinical multi-agent system for diabetes management to assist medical experts.
- Building small expert LLMs for real-world prescribing scenarios with GDPO-based search RL.
Nara Information
[AUG 2023 - FEB 2024] @South Korea
Research Intern Metaverse lab team
- Designed domain specific sLLM for local government
- Develped tour recommendation system combined with LLM by RAG method
- Assisted Korean curtural contents project using commercial AI systems.
Song Lab(Lingustics Lab), Korea Univ.
[May 2022 - FEB 2023] @South Korea
Researcher Korean AI dataset team (host: Prof. Sanghoun Song)
- Joined Korean legal/bidomedical AI dataset project.
- Worked as crowdworker for legal data tagging and labelling.
Research Intern Advisor: Sanghoon Lee
- Developed on-premise clinical multi-agent system for diabetes management to assist medical experts.
- Building small expert LLMs for real-world prescribing scenarios with GDPO-based search RL.
Research Intern Metaverse lab team
- Designed domain specific sLLM for local government
- Develped tour recommendation system combined with LLM by RAG method
- Assisted Korean curtural contents project using commercial AI systems.
Researcher Korean AI dataset team (host: Prof. Sanghoun Song)
- Joined Korean legal/bidomedical AI dataset project.
- Worked as crowdworker for legal data tagging and labelling.
Projects
- Safety Training Methods using Transformer Circuits.
- Differentiate Specific Emergent Attention Heads using Transforemr Circuits.
- Temporal Alignment through Chronosemanticity.
- Supported to research on knowledge distillation method.
- Utilize Knowledge Hierarchy.
- Developed Korean local tour recommendation system combined with LLM by RAG methods.
- Designed pipeline of recommendation using personalized tour data, with efficient ML methods.
- [Available GPTs ver]
- [link to the post]
- Developed sLLM specialized to administrative and civil affairs works for local government's officers.
- Developed summarization and search agents among the entire LLM pipeline.
- [link to the post]
Honors and Scholarships
Academic Services
- 3rd Conference on Language Modeling
- Participated as a reviewer
- The 64rd Annual Meeting of the Association for Computational Linguistics
- Participated as a secondary reviewer
- The 2025 Conference on Empirical Methods in Natural Language Processing
- Participated as a secondary reviewer
- The 63rd Annual Meeting of the Association for Computational Linguistics
- Participated as a secondary reviewer