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Diffusion models excel at generating images conditioned on text prompts, but the resulting images often do not satisfy user-specific criteria measured by scalar rewards such as Aesthetic Scores. This alignment typically requires…

Direct Preference Optimization (DPO) has gained attention as an efficient alternative to reinforcement learning from human feedback (RLHF) for aligning large language models (LLMs) with human preferences. Despite its advantages, DPO suffers…

Computation and Language · Computer Science 2025-02-21 Ruichen Shao , Bei Li , Gangao Liu , Yang Chen , Xiang Zhou , Jingang Wang , Xunliang Cai , Peng Li

We present Diffusion-KTO, a novel approach for aligning text-to-image diffusion models by formulating the alignment objective as the maximization of expected human utility. Since this objective applies to each generation independently,…

Computer Vision and Pattern Recognition · Computer Science 2024-10-15 Shufan Li , Konstantinos Kallidromitis , Akash Gokul , Yusuke Kato , Kazuki Kozuka

Diffusion models have achieved remarkable results in image generation, and have similarly been used to learn high-performing policies in sequential decision-making tasks. Decision-making diffusion models can be trained on lower-quality…

Machine Learning · Computer Science 2023-12-12 Felipe Nuti , Tim Franzmeyer , João F. Henriques

This tutorial provides a comprehensive survey of methods for fine-tuning diffusion models to optimize downstream reward functions. While diffusion models are widely known to provide excellent generative modeling capability, practical…

Machine Learning · Computer Science 2024-07-19 Masatoshi Uehara , Yulai Zhao , Tommaso Biancalani , Sergey Levine

Inference-time alignment provides an efficient alternative for aligning LLMs with humans. However, these approaches still face challenges, such as limited scalability due to policy-specific value functions and latency during the inference…

Computation and Language · Computer Science 2025-05-27 Ruizhe Chen , Wenhao Chai , Zhifei Yang , Xiaotian Zhang , Joey Tianyi Zhou , Tony Quek , Soujanya Poria , Zuozhu Liu

Using reinforcement learning with human feedback (RLHF) has shown significant promise in fine-tuning diffusion models. Previous methods start by training a reward model that aligns with human preferences, then leverage RL techniques to…

Machine Learning · Computer Science 2024-03-26 Kai Yang , Jian Tao , Jiafei Lyu , Chunjiang Ge , Jiaxin Chen , Qimai Li , Weihan Shen , Xiaolong Zhu , Xiu Li

Recent flow matching models for text-to-image generation have achieved remarkable quality, yet their integration with reinforcement learning for human preference alignment remains suboptimal, hindering fine-grained reward-based…

Computer Vision and Pattern Recognition · Computer Science 2025-10-16 Xiaoxuan He , Siming Fu , Yuke Zhao , Wanli Li , Jian Yang , Dacheng Yin , Fengyun Rao , Bo Zhang

Model-based reinforcement learning methods often use learning only for the purpose of estimating an approximate dynamics model, offloading the rest of the decision-making work to classical trajectory optimizers. While conceptually simple,…

Machine Learning · Computer Science 2022-12-22 Michael Janner , Yilun Du , Joshua B. Tenenbaum , Sergey Levine

Preference learning has garnered extensive attention as an effective technique for aligning diffusion models with human preferences in visual generation. However, existing alignment approaches such as Diffusion-DPO suffer from two…

Machine Learning · Computer Science 2026-05-19 Xiaomeng Yang , Mengping Yang , Junyan Wang , Zhijian Zhou , Zhiyu Tan , Hao Li

We address the problem of fine-tuning diffusion models for reward-guided generation in biomolecular design. While diffusion models have proven highly effective in modeling complex, high-dimensional data distributions, real-world…

In this paper, we study the optimal dividend problem under the continuous time diffusion model with the bounded dividend rate from the Reinforcement Learning (RL) perspective. Unlike the standard literature, our main focus will be on…

Optimization and Control · Mathematics 2026-03-30 Lihua Bai , Thejani Gamage , Jin Ma , Gaozhan Wang

Diffusion models have achieved remarkable success in conditional image generation, yet their outputs often remain misaligned with human preferences. To address this, recent work has applied Direct Preference Optimization (DPO) to diffusion…

Computer Vision and Pattern Recognition · Computer Science 2025-11-12 Shaomeng Wang , He Wang , Xiaolu Wei , Longquan Dai , Jinhui Tang

Preference optimization has emerged as an efficient alternative to online reinforcement learning from human feedback (RLHF) for aligning text-to-image diffusion models. However, existing methods largely reduce supervision to binary pairwise…

Machine Learning · Computer Science 2026-05-27 Austin Wang , Jiaqi Han , Stefano Ermon , Yisong Yue

Offline reinforcement learning (RL) aims to learn optimal policies from previously collected datasets. Recently, due to their powerful representational capabilities, diffusion models have shown significant potential as policy models for…

Machine Learning · Computer Science 2024-05-30 Tianle Zhang , Jiayi Guan , Lin Zhao , Yihang Li , Dongjiang Li , Zecui Zeng , Lei Sun , Yue Chen , Xuelong Wei , Lusong Li , Xiaodong He

In reinforcement learning (RL), agents continually interact with the environment and use the feedback to refine their behavior. To guide policy optimization, reward models are introduced as proxies of the desired objectives, such that when…

Machine Learning · Computer Science 2025-06-19 Rui Yu , Shenghua Wan , Yucen Wang , Chen-Xiao Gao , Le Gan , Zongzhang Zhang , De-Chuan Zhan

Recent developments in offline reinforcement learning have uncovered the immense potential of diffusion modeling, which excels at representing heterogeneous behavior policies. However, sampling from diffusion policies is considerably slow…

Machine Learning · Computer Science 2024-03-18 Huayu Chen , Cheng Lu , Zhengyi Wang , Hang Su , Jun Zhu

Safe and effective motion planning is crucial for autonomous robots. Diffusion models excel at capturing complex agent interactions, a fundamental aspect of decision-making in dynamic environments. Recent studies have successfully applied…

Robotics · Computer Science 2025-07-18 Giwon Lee , Daehee Park , Jaewoo Jeong , Kuk-Jin Yoon

Diffusion-based policies have gained growing popularity in solving a wide range of decision-making tasks due to their superior expressiveness and controllable generation during inference. However, effectively training large diffusion…

Post-training alignment of diffusion models relies on simplified signals, such as scalar rewards or binary preferences. This limits alignment with complex human expertise, which is hierarchical and fine-grained. To address this, we first…

Computer Vision and Pattern Recognition · Computer Science 2026-01-09 Chenye Meng , Zejian Li , Zhongni Liu , Yize Li , Changle Xie , Kaixin Jia , Ling Yang , Huanghuang Deng , Shiying Ding , Shengyuan Zhang , Jiayi Li , Lingyun Sun