Ph.D. Student · AI-ISL Lab · Yonsei University

Yeachan Jun

I am a Ph.D. student at the Graduate School of Artificial Intelligence, Yonsei University, advised by Prof. Albert No. My research studies privacy and security issues in modern language models, with a focus on membership inference for diffusion language models and the conceptual foundations of machine unlearning in LLMs.

About

Researcher profile

I am currently a Ph.D. student at the AI-ISL Lab, Yonsei University. My work focuses on privacy risks, auditing methods, and evaluation problems that arise as language models move beyond standard autoregressive generation.

Recent projects include single-pass membership inference for fine-tuned diffusion language models and position work on how the term “machine unlearning” is used in the context of LLMs. Previously, I graduated early and at the top of my class from the Department of Mathematics at Kwangwoon University, with a GPA of 4.44/4.5.

Membership Inference

I study how training-data membership can be detected in fine-tuned language models, especially diffusion language models.

Diffusion Language Models

My current work investigates privacy signals and efficient auditing methods for non-autoregressive language generation.

Machine Unlearning in LLMs

I am interested in clarifying what unlearning should mean for LLMs and how claims about unlearning should be evaluated.

Publications

Selected work

Recent papers on privacy, membership inference, diffusion language models, and machine unlearning in LLMs.

ICML 2026 Workshop on Foundations of Deep Generative Models

JUMP: Single-Pass Membership Inference on Fine-Tuned Diffusion Language Models

Yeachan Jun, Albert No

A membership inference study for fine-tuned diffusion language models, focusing on efficient single-pass privacy signals for identifying training-data membership.

Diffusion Language ModelsMembership InferencePrivacy AuditingFDGM Workshop
Paper

ICML 2026 · Position Paper

Position: The Term “Machine Unlearning” Is Overused in LLMs

Sangyeon Yoon*, Yeachan Jun*, Albert No * Equal contribution

A position paper arguing for more precise use of the term “machine unlearning” in LLM research and clearer evaluation of what unlearning methods actually achieve.

Machine UnlearningLLMsEvaluationPosition Paper
ICML

Research

Research directions

01

Single-Pass Privacy Auditing

Designing efficient membership inference signals that reduce the cost of auditing fine-tuned diffusion language models.

02

Privacy in Diffusion Language Models

Understanding how non-autoregressive generation changes the privacy risks and attack surfaces of language models.

03

Unlearning Terminology and Evaluation

Clarifying the conceptual gap between removing information, changing behavior, and claiming machine unlearning in LLMs.

Education

Academic background

Yonsei University

Ph.D. Student, Graduate School of Artificial Intelligence

Mar 2024 – Present · AI-ISL Lab · Advisor: Prof. Albert No

Kwangwoon University

B.S. in Mathematics

Mar 2018 – Aug 2023 · GPA: 4.44/4.5 · Early graduation · Summa cum laude

Honors

Awards & honors

President's Award, LX Korea Land and Geospatial Informatix Corporation

First Prize, The Startup Competition for Big Data in Spatial Convergence · Sep 2024

Dean's List Academic Honors

Multiple semesters, including first-place distinctions in the department.

Contact

Get in touch

For research discussion, collaboration, or questions, feel free to contact me by email.