Constrained Auto-Bidding via Generative Response Modeling
arXiv preprint · 2026
I am a machine learning research engineer at NAVER, where I apply reinforcement learning to large-scale, real-world decision making — recommender systems and auto-bidding in online advertising auctions.
My research interests include offline RL for recommender systems and auto-bidding, and robot learning with vision-language-action (VLA) models and world action models.
Before NAVER, I completed my M.Sc. in Machine Learning at the University of Freiburg, Germany, and my B.Sc. in Applied Mathematics and Computer Science at Linnaeus University, Sweden.
arXiv preprint · 2026
Preprint · 2026
Korean Patent Publication No. 10-2025-0124713 (2025.08.20) · NAVER Corp · 2025
arXiv preprint · 2024
NeurIPS · 2023
@inproceedings{an2023direct,
title={Direct Preference-based Policy Optimization without Reward Modeling},
author={An, Gaon and Lee, Junhyeok and Zuo, Xingdong and Kosaka, Norio and Kim, Kyung-Min and Song, Hyun Oh},
booktitle={Advances in Neural Information Processing Systems},
volume={36},
year={2023}
} Technical report · 2021
NeuroQuantology, 12(4) · 2014
@article{zuo2014numerical,
title={Numerical Simulation of Asano-Khrennikov-Ohya Quantum-like Decision Making Model},
author={Zuo, Xingdong},
journal={NeuroQuantology},
volume={12},
number={4},
year={2014}
} DAN 25 — NAVER Conference, Seoul · 2025
Seoul · 2025
Authored much of the standard wrapper suite — ClipAction, RescaleAction, FrameStack/LazyFrames, GrayScaleObservation, ResizeObservation, TransformObservation/Reward, FilterObservation, FlattenObservation, RecordEpisodeStatistics, AtariPreprocessing — plus vectorized-environment infrastructure. These wrappers live on in Gymnasium.
Early core contributions, including the DataLoader drop_last flag and nn.utils parameters_to_vector / vector_to_parameters.
Contributions to Hugging Face's robot-learning library, including batched video encoding for faster dataset recording and the CLI for launching LeKiwiHost.
A terminal control center for the LeKiwi robot workflow, built with LeRobot and pyratatui.
A modern, modular reinforcement learning library for auto-bidding — a personal side project.
A light PyTorch infrastructure for rapid prototyping of reinforcement learning algorithms — modular building blocks for agents, environments, and parallelized experiments.
A customizable framework to create maze and gridworld environments for reinforcement learning, with a simple API for designing your own layouts. Cited in academic papers as a benchmark environment.
PyTorch implementation of Value Iteration Networks (NIPS 2016 best paper), with live training visualization in Visdom.
A thin wrapper that converts DeepMind Control Suite environments into the OpenAI Gym interface.
PyTorch implementation of "Improving PILCO with Bayesian Neural Network Dynamics Models" — model-based RL with uncertainty-aware dynamics.
An efficient PyTorch implementation of the evaluation metrics used in recommender systems.
A customizable recommender-system simulator exposed through the OpenAI Gym interface, for training and evaluating RL-based recommenders.
Smaller merged patches in TensorFlow, OpenAI Baselines, Hugging Face TRL, torchmetrics, and pytorch/examples.