Chaeyun Jang

I'm a PhD student at KAIST AI, advised by Prof. Juho Lee, and currently a research intern at Kakao.

What ultimately motivates my research is a form of inequality that comes not from access to AI, but from differences in how people are able to use it (Hargittai, 2002; Lee et al., 2026). As models become more capable, they can widen the gap between users who know how to test, question, and guide them toward deeper answers and users who receive more generic responses.

One research direction toward addressing this gap is LLM calibration. I study how language models can better recognize and express what they do not know, so that their uncertainty helps users reason more carefully instead of simply making the model sound confident.

Anyone interested in discussing uncertainty calibration is always welcome to reach out.

MS in AI, KAIST  ·  BS in Statistics & Computer Science, Sungkyunkwan University.

Publications

Confidence is Not Universal

Confidence is Not Universal: Task-Dependent Calibration and Emergent Behavior in LLMs

Chaeyun Jang, Moonseok Choi, Yegon Kim, Seungyoo Lee, Juho Lee†, Hyungi Lee† (†co-corresponding)

ICML 2026

Missing Modality

Bridging the Missing-Modality Gap: Improving Text-Only Calibration of Vision Language Models

Mingyeong Kim, Jungwon Choi, Chaeyun Jang, Juho Lee

ICLR 2026 Trustworthy AI Workshop

CalibRAG

Reliable Decision-Making via Calibration-Oriented Retrieval-Augmented Generation

Chaeyun Jang, Deukhwan Cho, Seanie Lee, Hyungi Lee, Juho Lee

NeurIPS 2025

Verbalized Confidence

Verbalized Confidence Triggers Self-Verification: Emergent Behavior Without Explicit Reasoning Supervision

Chaeyun Jang, Moonseok Choi, Yegon Kim, Hyungi Lee, Juho Lee

ICML 2025 R2-FM Workshop

DANP

Dimension Agnostic Neural Processes

Hyungi Lee, Chaeyun Jang, Dongbok Lee, Juho Lee

ICLR 2025

BO-Fusion

Model Fusion through Bayesian Optimization in Language Model Fine-Tuning

Chaeyun Jang*, Hyungi Lee*, Jungtaek Kim†, Juho Lee† (*equal contribution, †co-corresponding)

NeurIPS 2024 Spotlight (top 2.1%, 327/15671)

Experience

Part-Time Research Scientist

Kakao, Language Model Team  ·  Seongnam, South Korea

Undergraduate Research Intern

Sungkyunkwan University  ·  advised by JinYeong Bak

Computer Vision Intern

Nuvilab Inc.  ·  Food-tech AI startup, Seoul

Teaching

Teaching Assistant

KAIST  ·  AI708: Bayesian Machine Learning

Talks

Reliable Decision-Making via Calibration-Oriented Retrieval-Augmented Generation

AI Tutorial Series, Seoul AI Hub  ·  Seoul, South Korea

Tutorial Talk  ·  poster

Model Fusion through Bayesian Optimization in Language Model Fine-Tuning

AI Technology Showcase 2025, KAIST Graduate School of AI  ·  COEX, Seoul, South Korea

Research Showcase Presentation  ·  news

Academic Service

Conference Reviewer

NeurIPS, ICLR, ICML

Silver Reviewer Award ICML 2026