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Xianyuan Zhan

41 accepted papers

2026

Demystifying Action Space Design for Robotic Manipulation Policies

ICML 2026poster

The specification of the action space plays a pivotal role in imitation-based robotic manipulation policy learning, fundamentally shaping the optimization landscape of policy learning. While recent advances have focused heavily on scaling training data and model capacity, the choice of action space …

Cited by 0SourceScholar
2026

Dichotomous Diffusion Policy Optimization

ICLR 2026poster

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 policies using reinforcement learning (RL) remains challenging. Ex…

Cited by 0SourcecodeScholar
2026

Discrete Diffusion for Reflective Vision-Language-Action Models in Autonomous Driving

ICLR 2026poster

End-to-End (E2E) solutions have emerged as a mainstream approach for autonomous driving systems, with Vision-Language-Action (VLA) models representing a new paradigm that leverages pre-trained multimodal knowledge from Vision-Language Models (VLMs) to interpret and interact with complex real-world e…

Cited by 0SourcecodeScholar
2026

Sample Efficient Offline RL via T-Symmetry Enforced Latent State-Stitching

ICLR 2026poster

Offline reinforcement learning (RL) has achieved notable progress in recent years. However, most existing offline RL methods require a large amount of training data to achieve reasonable performance and offer limited out-of-distribution (OOD) generalization capability due to conservative data-relate…

Cited by 0SourceScholar
2026

X-VLA: Soft-Prompted Transformer as Scalable Cross-Embodiment Vision-Language-Action Model

ICLR 2026poster

Successful generalist Vision-Language-Action (VLA) models that rely on effective training across diverse robotic platforms with large-scale, cross-embodiment, heterogeneous datasets. To facilitate and leverage the heterogeneity in rich, diverse robotic data sources, we propose a novel Soft Prompt ap…

Cited by 0SourcecodeScholar
2025

Are Expressive Models Truly Necessary for Offline RL?

AAAI 2025technical

Among various branches of offline reinforcement learning (RL) methods, goal-conditioned supervised learning (GCSL) has gained increasing popularity as it formulates the offline RL problem as a sequential modeling task, therefore bypassing the notoriously difficult credit assignment challenge of valu…

2025

Data Center Cooling System Optimization Using Offline Reinforcement Learning

ICLR 2025poster

The recent advances in information technology and artificial intelligence have fueled a rapid expansion of the data center (DC) industry worldwide, accompanied by an immense appetite for electricity to power the DCs. In a typical DC, around 30-40% of the energy is spent on the cooling system rather…

Cited by 0SourcePDFScholar
2025

Diffusion-Based Planning for Autonomous Driving with Flexible Guidance

ICLR 2025oral

Achieving human-like driving behaviors in complex open-world environments is a critical challenge in autonomous driving. Contemporary learning-based planning approaches such as imitation learning methods often struggle to balance competing objectives and lack of safety assurance,due to limited adapt…

Cited by 3SourcePDFScholar
2025

Efficient Robotic Policy Learning via Latent Space Backward Planning

ICML 2025poster

Current robotic planning methods often rely on predicting multi-frame images with full pixel details. While this fine-grained approach can serve as a generic world model, it introduces two significant challenges for downstream policy learning: substantial computational costs that hinder real-time de…

2025

Flow Matching-Based Autonomous Driving Planning with Advanced Interactive Behavior Modeling

NeurIPS 2025poster

Modeling interactive driving behaviors in complex scenarios remains a fundamental challenge for autonomous driving planning. Learning-based approaches attempt to address this challenge with advanced generative models, removing the dependency on over-engineered architectures for representation fusion…

Cited by 0SourceScholar
2025

H2O+: An Improved Framework for Hybrid Offline-and-Online RL with Dynamics Gaps

ICRA 2025

Solving real-world complex tasks using reinforcement learning (RL) without high-fidelity simulation environments or large amounts of offline data can be quite challenging. Online RL agents trained in imperfect simulation environments can suffer from severe sim-to-real issues. Offline RL approaches a

Cited by 17SourceScholar
2025

Robo-MUTUAL: Robotic Multimodal Task Specification via Unimodal Learning

ICRA 2025

Multimodal task specification is essential for enhanced robotic performance, where Cross-modality Alignment enables the robot to holistically understand complex task instructions. Directly annotating multimodal instructions for model training proves impractical, due to the sparsity of paired multimo

Cited by 5SourceScholar
2025

Skill Expansion and Composition in Parameter Space

ICLR 2025poster

Humans excel at reusing prior knowledge to address new challenges and developing skills while solving problems. This paradigm becomes increasingly popular in the development of autonomous agents, as it develops systems that can self-evolve in response to new challenges like human beings. However, pr…

2025

Towards Robust Zero-Shot Reinforcement Learning

NeurIPS 2025poster

The recent development of zero-shot reinforcement learning (RL) has opened a new avenue for learning pre-trained generalist policies that can adapt to arbitrary new tasks in a zero-shot manner. While the popular Forward-Backward representations (FB) and related methods have shown promise in zero-sho…

Cited by 0SourcecodeScholar
2025

Uni-RL: Unifying Online and Offline RL via Implicit Value Regularization

NeurIPS 2025poster

The practical use of reinforcement learning (RL) requires handling diverse settings, including online, offline, and offline-to-online learning. Instead of developing separate algorithms for each setting, we propose Uni-RL, a unified model-free RL framework that addresses all these scenarios within a…

Cited by 0SourceScholar
2025

Universal Actions for Enhanced Embodied Foundation Models

CVPR 2025poster

Training on diverse, internet-scale data is a key factor in the success of recent large foundation models. Yet, using the same recipe for building embodied agents has faced noticeable difficulties. Despite the availability of many crowd-sourced embodied datasets, their action spaces often exhibit si…

2024

A Comprehensive Survey of Cross-Domain Policy Transfer for Embodied Agents

IJCAI 2024poster

The burgeoning fields of robot learning and embodied AI have triggered an increasing demand for large quantities of data. However, collecting sufficient unbiased data from the target domain remains a challenge due to costly data collection processes and stringent safety requirements. Consequently, r…

2024

DecisionNCE: Embodied Multimodal Representations via Implicit Preference Learning

ICML 2024poster

Multimodal pretraining is an effective strategy for the trinity of goals of representation learning in autonomous robots: $1)$ extracting both local and global task progressions; $2)$ enforcing temporal consistency of visual representation; $3)$ capturing trajectory-level language grounding. Most ex…

2024

Diffusion-DICE: In-Sample Diffusion Guidance for Offline Reinforcement Learning

NeurIPS 2024poster

One important property of DIstribution Correction Estimation (DICE) methods is that the solution is the optimal stationary distribution ratio between the optimized and data collection policy. In this work, we show that DICE-based methods can be viewed as a transformation from the behavior distributi…

Cited by 8SourcePDFScholar
2024

Instruction-Guided Visual Masking

NeurIPS 2024poster

Instruction following is crucial in contemporary LLM. However, when extended to multimodal setting, it often suffers from misalignment between specific textual instruction and targeted local region of an image. To achieve more accurate and nuanced multimodal instruction following, we introduce Instr…

2024

ODICE: Revealing the Mystery of Distribution Correction Estimation via Orthogonal-gradient Update

ICLR 2024spotlight

In this study, we investigate the DIstribution Correction Estimation (DICE) methods, an important line of work in offline reinforcement learning (RL) and imitation learning (IL). DICE-based methods impose state-action-level behavior constraint, which is an ideal choice for offline learning. However,…

2024

OMPO: A Unified Framework for RL under Policy and Dynamics Shifts

ICML 2024oral

Training reinforcement learning policies using environment interaction data collected from varying policies or dynamics presents a fundamental challenge. Existing works often overlook the distribution discrepancies induced by policy or dynamics shifts, or rely on specialized algorithms with task pri…

2024

Offline-Boosted Actor-Critic: Adaptively Blending Optimal Historical Behaviors in Deep Off-Policy RL

ICML 2024poster

Off-policy reinforcement learning (RL) has achieved notable success in tackling many complex real-world tasks, by leveraging previously collected data for policy learning. However, most existing off-policy RL algorithms fail to maximally exploit the information in the replay buffer, limiting sample…

2024

OpenChat: Advancing Open-source Language Models with Mixed-Quality Data

ICLR 2024poster

Nowadays, open-source large language models like LLaMA have emerged. Recent developments have incorporated supervised fine-tuning (SFT) and reinforcement learning fine-tuning (RLFT) to align these models with human goals. However, SFT methods treat all training data with mixed quality equally, while…

2024

Query-Policy Misalignment in Preference-Based Reinforcement Learning

ICLR 2024spotlight

Preference-based reinforcement learning (PbRL) provides a natural way to align RL agents’ behavior with human desired outcomes, but is often restrained by costly human feedback. To improve feedback efficiency, most existing PbRL methods focus on selecting queries to maximally improve the overall qua…

2024

Safe Offline Reinforcement Learning with Feasibility-Guided Diffusion Model

ICLR 2024poster

Safe offline reinforcement learning is a promising way to bypass risky online interactions towards safe policy learning. Most existing methods only enforce soft constraints, i.e., constraining safety violations in expectation below thresholds predetermined. This can lead to potentially unsafe outcom…

2024

Seizing Serendipity: Exploiting the Value of Past Success in Off-Policy Actor-Critic

ICML 2024poster

Learning high-quality $Q$-value functions plays a key role in the success of many modern off-policy deep reinforcement learning (RL) algorithms. Previous works primarily focus on addressing the value overestimation issue, an outcome of adopting function approximators and off-policy learning. Deviati…

2023

Look Beneath the Surface: Exploiting Fundamental Symmetry for Sample-Efficient Offline RL

NeurIPS 2023poster

Offline reinforcement learning (RL) offers an appealing approach to real-world tasks by learning policies from pre-collected datasets without interacting with the environment. However, the performance of existing offline RL algorithms heavily depends on the scale and state-action space coverage of d…

2023

Mind the Gap: Offline Policy Optimization for Imperfect Rewards

ICLR 2023poster

Reward function is essential in reinforcement learning (RL), serving as the guiding signal to incentivize agents to solve given tasks, however, is also notoriously difficult to design. In many cases, only imperfect rewards are available, which inflicts substantial performance loss for RL agents. In…

2023

Offline Multi-Agent Reinforcement Learning with Implicit Global-to-Local Value Regularization

NeurIPS 2023poster

Offline reinforcement learning (RL) has received considerable attention in recent years due to its attractive capability of learning policies from offline datasets without environmental interactions. Despite some success in the single-agent setting, offline multi-agent RL (MARL) remains to be a chal…

2023

Offline RL with No OOD Actions: In-Sample Learning via Implicit Value Regularization

ICLR 2023top-5%

Most offline reinforcement learning (RL) methods suffer from the trade-off between improving the policy to surpass the behavior policy and constraining the policy to limit the deviation from the behavior policy as computing $Q$-values using out-of-distribution (OOD) actions will suffer from errors d…

2023

When Data Geometry Meets Deep Function: Generalizing Offline Reinforcement Learning

ICLR 2023poster

In offline reinforcement learning (RL), one detrimental issue to policy learning is the error accumulation of deep \textit{Q} function in out-of-distribution (OOD) areas. Unfortunately, existing offline RL methods are often over-conservative, inevitably hurting generalization performance outside dat…

2022

A Policy-Guided Imitation Approach for Offline Reinforcement Learning

NeurIPS 2022accept

Offline reinforcement learning (RL) methods can generally be categorized into two types: RL-based and Imitation-based. RL-based methods could in principle enjoy out-of-distribution generalization but suffer from erroneous off-policy evaluation. Imitation-based methods avoid off-policy evaluation but…

2022

Adversarial Contrastive Learning via Asymmetric InfoNCE

ECCV 2022poster

"Contrastive learning (CL) has recently been applied to adversarial learning tasks. Such practice considers adversarial perturbations as additional positive samples of an instance, and by maximizing their agreements with each other, yields better adversarial robustness. However, this mechanism can b…

2022

Constraints Penalized Q-learning for Safe Offline Reinforcement Learning

AAAI 2022technical

We study the problem of safe offline reinforcement learning (RL), the goal is to learn a policy that maximizes long-term reward while satisfying safety constraints given only offline data, without further interaction with the environment. This problem is more appealing for real world RL applications…

Cited by 105SourcePDFScholar
2022

DeepThermal: Combustion Optimization for Thermal Power Generating Units Using Offline Reinforcement Learning

AAAI 2022technical

Optimizing the combustion efficiency of a thermal power generating unit (TPGU) is a highly challenging and critical task in the energy industry. We develop a new data-driven AI system, namely DeepThermal, to optimize the combustion control strategy for TPGUs. At its core, is a new model-based offlin…

Cited by 87SourcePDFScholar
2022

Discriminator-Guided Model-Based Offline Imitation Learning

CoRL 2022poster

Offline imitation learning (IL) is a powerful method to solve decision-making problems from expert demonstrations without reward labels. Existing offline IL methods suffer from severe performance degeneration under limited expert data. Including a learned dynamics model can potentially improve the s…

Cited by 22SourceScholar
2022

Discriminator-Weighted Offline Imitation Learning from Suboptimal Demonstrations

ICML 2022spotlight

We study the problem of offline Imitation Learning (IL) where an agent aims to learn an optimal expert behavior policy without additional online environment interactions. Instead, the agent is provided with a supplementary offline dataset from suboptimal behaviors. Prior works that address this prob…

2022

When to Trust Your Simulator: Dynamics-Aware Hybrid Offline-and-Online Reinforcement Learning

NeurIPS 2022accept

Learning effective reinforcement learning (RL) policies to solve real-world complex tasks can be quite challenging without a high-fidelity simulation environment. In most cases, we are only given imperfect simulators with simplified dynamics, which inevitably lead to severe sim-to-real gaps in RL po…

2021

Robust Spatio-Temporal Purchase Prediction via Deep Meta Learning

AAAI 2021technical

Purchase prediction is an essential task in both online and offline retail industry, especially during major shopping festivals, when strong promotion boosts consumption dramatically. It is important for merchants to forecast such surge of sales and have better preparation. This is a challenging pro…

Cited by 16SourcePDFScholar