Joshua Tian Jin Tee

Joshua Tian Jin Tee

also written Joshua Tee Tian Jin
Ph.D. Candidate
KAIST Electrical Engineering
Generative AI · Diffusion & Flow-Based Models

About

I am Joshua Tian Jin Tee (also written Joshua Tee Tian Jin), a generative AI researcher working on diffusion models, with a focus on preference learning to improve generation quality and reliability.

My research aims to reduce failure cases in diffusion-based generative systems by using preference signals to better align model outputs with user intent, while also improving sampling efficiency to support real-world applications.

Research Focus

My current work studies how preference signals and sampling dynamics interact in diffusion models, and how these interactions can be used to improve generation quality, reliability, and efficiency.

Publications

Diffusion Negative Preference Optimization Made Simple
Joshua Tian Jin Tee, Hee Suk Yoon, Sunjae Yoon, Tri Ton, Chang D. Yoo
ICLR 2026

We show that a single diffusion model can learn from both positive and negative preference pairs through a bounded objective, removing the need for a separate negative model while keeping optimization stable and efficient.

TESSAR: Geometry-Aware Active Regression via Dynamic Voronoi Tessellation
Seong Jin Cho, Gwangsu Kim, Junghyun Lee, Hee Suk Yoon, Joshua Tian Jin Tee, Chang D. Yoo
ICLR 2026

An active learning method for regression that scores candidate samples using the geometry of a dynamic Voronoi tessellation, balancing informativeness, coverage, and representativeness.

A Gradient Guidance Perspective on Stepwise Preference Optimization for Diffusion Models
Joshua Tian Jin Tee, Hee Suk Yoon, Abu Hanif Muhammad Syarubany, Eunseop Yoon, Chang D. Yoo
NeurIPS 2025

This work reframes stepwise preference optimization as an implicit form of gradient-based guidance, offering theoretical insights into its stability and empirical effectiveness.

Physics Informed Distillation for Diffusion Models
Joshua Tian Jin Tee*, Kang Zhang*, Chanwoo Kim, Dhananjaya Nagaraja Gowda, Hee Suk Yoon, Chang D. Yoo
TMLR 2024

We distill a multi-step diffusion model into a single-step generator by learning the ODE governing its diffusion trajectory using a PINN-inspired formulation.

BI-MDRG: Bridging Image History in Multimodal Dialogue Response Generation
Hee Suk Yoon*, Eunseop Yoon*, Joshua Tian Jin Tee*, Kang Zhang, Yu-Jung Heo, Du-Seong Chang, Chang D. Yoo
ECCV 2024

We present a novel approach to multimodal dialogue that effectively bridges historical image context to improve the coherence of generated text responses.

Mitigating Adversarial Perturbations for Deep Reinforcement Learning via Vector Quantization
Tung Luu, Thanh Nguyen, Joshua Tian Jin Tee, Sungwoong Kim, Chang D. Yoo
IROS 2024

Investigates the use of Vector Quantization to defend DRL agents against adversarial attacks, ensuring robust performance in unpredictable environments.

C-TPT: Calibrated Test-Time Prompt Tuning for Vision-Language Models via Text Feature Dispersion
Hee Suk Yoon*, Eunseop Yoon*, Joshua Tian Jin Tee, Mark A. Hasegawa-Johnson, Yingzhen Li, Chang D. Yoo
ICLR 2024

Proposes a calibration method for test-time prompt tuning that uses text feature dispersion to enhance the reliability of vision-language model predictions.

ESD: Expected Squared Difference as a Tuning-Free Trainable Calibration Measure
Hee Suk Yoon*, Joshua Tian Jin Tee*, Eunseop Yoon, Sunjae Yoon, Gwangsu Kim, Yingzhen Li, Chang D. Yoo
ICLR 2023

This paper proposes a differentiable calibration metric that eliminates the need for post-hoc tuning, enabling end-to-end optimization of uncertainty estimates.

* indicates equal contribution

Education

  • Doctor of Philosophy KAIST
    Electrical Engineering
    2023 – Present
  • Master of Science KAIST
    Electrical Engineering
    2022 – 2023
  • Bachelor of Science KAIST
    Double Major in Mathematics and Physics
    2018 – 2022

Services & Awards

Academic Service

  • Reviewer: NeurIPS 2025, ICLR 2026, ICML 2026, NeurIPS 2026

Awards

  • Top Reviewer: NeurIPS 2025