← Search

Lei Song

34 accepted papers

2026

3DMedAgent: Unified Perception-to-Understanding for 3D Medical Analysis

ICML 2026poster

3D CT analysis spans a continuum from low-level perception to high-level clinical understanding. Existing 3D-oriented analysis methods adopt either isolated task-specific modeling or task-agnostic end-to-end paradigms to produce one-hop outputs, impeding the systematic accumulation of perceptual evi…

Cited by 2SourceScholar
2026

Diffusion Stabilizer Policy for Automated Surgical Robot Manipulations

ICRA 2026poster

Intelligent surgical robots have the potential to revolutionize clinical practice by enabling more precise and automated surgical procedures. However, the automation of such robot for surgical tasks remains under-explored compared to recent advancements in solving household manipulation tasks. These…

2026

Experience-Evolving Multi-Turn Tool-Use Agent with Hybrid Episodic–Procedural Memory

ICML 2026poster

As intents unfold and environments change, multi-turn agents face continuously shifting decision contexts. Although reusing past experience is intuitively appealing, existing approaches remain limited: full trajectories are often too context-specific to transfer, while tool-level reuse ignores the c…

Cited by 0SourceScholar
2026

Holdout-Loss-Based Data Selection for LLM Finetuning via In-Context Learning

ICLR 2026poster

Fine-tuning large pretrained language models is a common approach for aligning them with human preferences, but noisy or off-target examples can dilute supervision. While small, well-chosen datasets often match the performance of much larger ones, systematic and efficient ways to identify high-value…

Cited by 0SourceScholar
2026

In-Context Compositional Q-Learning for Offline Reinforcement Learning

ICLR 2026poster

Accurately estimating the Q-function is a central challenge in offline reinforcement learning. However, existing approaches often rely on a single global Q-function, which struggles to capture the compositional nature of tasks involving diverse subtasks. We propose In-context Compositional Q-Learnin…

Cited by 0SourceScholar
2026

PixelCraft: A Multi-Agent system for High-Fidelity Visual Reasoning on Structured Images

ICLR 2026poster

Structured images (e.g., charts and geometric diagrams) remain challenging for multimodal large language models (MLLMs), as perceptual slips can cascade into erroneous conclusions. Intermediate visual cues can steer reasoning; however, existing cue-based methods are constrained with low-fidelity ima…

Cited by 0SourceScholar
2026

See Less, See Right: Bi-directional Perceptual Shaping For Multimodal Reasoning

CVPR 2026

Large vision-language models (VLMs) often benefit from intermediate visual cues, either injected via external tools or generated as latent visual tokens during reasoning, but these mechanisms still overlook fine-grained visual evidence (e.g., polylines in charts), generalize poorly across domains, a

Cited by 0SourcecodeScholar
2026

SurgAM: Surgical Affordance Map Prediction with Multimodal Feature Fusion for Robot Autonomy

ICRA 2026poster

Surgical automation is being increasingly studied, yet bridging visual scene understanding with autonomous action planning remains a fundamental challenge. While much research effort has been made on scene perception (e.g., tool recognition and scene segmentation), understanding and predicting actio…

Cited by 0Scholar
2026

The Quality-Utility Paradox: Why High-Reward Data Impairs Small Model Reasoning

ICML 2026poster

Knowledge distillation from powerful reasoning models underpins the development of Small Language Models (SLMs). A prevailing assumption in this paradigm is that training data with higher perceived quality, often defined by rigorous logic and superior reward scores, monotonically enhances downstream…

Cited by 0SourceScholar
2025

Efficient Discovery of Pareto Front for Multi-Objective Reinforcement Learning

ICLR 2025poster

Multi-objective reinforcement learning (MORL) excels at handling rapidly changing preferences in tasks that involve multiple criteria, even for unseen preferences. However, previous dominating MORL methods typically generate a fixed policy set or preference-conditioned policy through multiple traini…

Cited by 0SourcePDFScholar
2025

Exploring Rationale Learning for Continual Graph Learning

AAAI 2025technical

Catastrophic forgetting poses a significant challenge for graph neural networks in continuously updating their knowledge base with data streams. To address this issue, much of the research has focused on node-level continual learning using parameter regularization or rehearsal-based strategies, whil…

Cited by 0SourcePDFScholar
2025

From Complex to Atomic: Enhancing Augmented Generation via Knowledge-Aware Dual Rewriting and Reasoning

ICML 2025poster

Recent advancements in Retrieval-Augmented Generation (RAG) systems have significantly enhanced the capabilities of large language models (LLMs) by incorporating external knowledge retrieval. However, the sole reliance on retrieval is often inadequate for mining deep, domain-specific knowledge and f…

Cited by 0SourcePDFScholar
2025

Graph Neural Network Enhanced Retrieval for Question Answering of Large Language Models

NAACL 2025long

Retrieval augmented generation has revolutionized large language model (LLM) outputs by providing factual supports. Nevertheless, it struggles to capture all the necessary knowledge for complex reasoning questions. Existing retrieval methods typically divide reference documents into passages, treati…

2025

HePa: Heterogeneous Graph Prompting for All-Level Classification Tasks

AAAI 2025technical

Heterogeneous graphs, which are common in real-world downstream tasks, have recently sparked a wave of research interest. The performance of end-to-end heterogeneous graph neural networks (HGNNs) greatly relies on supervised training for specific tasks. To reduce the labeling cost, the "pretrain-fin…

Cited by 0SourcePDFScholar
2025

Learning to Select In-Context Demonstration Preferred by Large Language Model

ACL 2025finding

In-context learning (ICL) enables large language models (LLMs) to adapt to new tasks during inference using only a few demonstrations. However, ICL performance is highly dependent on the selection of these demonstrations. Recent work explores retrieval-based methods for selecting query-specific demo…

Cited by 0SourcePDFScholar
2025

M2F2Net: Multi-stage Mixed Feature Fusion Network For Remote Sensing Change Detection

ICASSP 2025accepted

Remote sensing image change detection (CD) seeks to analyze and discern changes in surface objects through the use of multi-temporal remote sensing imagery. However, as image resolution advances, existing methods often fall short in capturing comprehensive visual feature representations, and their n…

Cited by 0SourceScholar
2025

NaDRO: Leveraging Dual-Reward Strategies for LLMs Training on Noisy Data

NeurIPS 2025poster

Group Relative Policy Optimization (GRPO) fine-tuning has been empirically shown to significantly enhance the reasoning abilities of language models. However, it often relies on large-scale, high-quality labeled data, which is typically difficult to obtain. To address this challenge, we introduce th…

Cited by 0SourceScholar
2025

OMGM: Orchestrate Multiple Granularities and Modalities for Efficient Multimodal Retrieval

ACL 2025long

Vision-language retrieval-augmented generation (RAG) has become an effective approach for tackling Knowledge-Based Visual Question Answering (KB-VQA), which requires external knowledge beyond the visual content presented in images. The effectiveness of Vision-language RAG systems hinges on multimoda…

2025

Reinforced In-Context Black-Box Optimization

IJCAI 2025

Black-Box Optimization (BBO) has found successful applications in many fields of science and engineering. Recently, there has been a growing interest in meta-learning particular components of BBO algorithms to speed up optimization and get rid of tedious hand-crafted heuristics. As an extension, lea

2025

Unveiling Markov heads in Pretrained Language Models for Offline Reinforcement Learning

ICML 2025poster

Recently, incorporating knowledge from pretrained language models (PLMs) into decision transformers (DTs) has generated significant attention in offline reinforcement learning (RL). These PLMs perform well in RL tasks, raising an intriguing question: what kind of knowledge from PLMs has been transfe…

Cited by 0SourcePDFScholar
2024

Diversification of Adaptive Policy for Effective Offline Reinforcement Learning

IJCAI 2024poster

Offline Reinforcement Learning (RL) aims to learn policies from pre-collected datasets that capture only a subset of the environment's dynamics. The predominant approach has been to solve a constrained optimization formulation, which ensures that the policy visits state-action pairs within the suppo…

Cited by 0SourcePDFScholar
2024

Hard Prompts Made Interpretable: Sparse Entropy Regularization for Prompt Tuning with RL

ACL 2024long

With the advent of foundation models, prompt tuning has positioned itself as an important technique for directing model behaviors and eliciting desired responses. Prompt tuning regards selecting appropriate keywords included into the input, thereby adapting to the downstream task without adjusting o…

2024

Monte Carlo Tree Search based Space Transfer for Black Box Optimization

NeurIPS 2024spotlight

Bayesian optimization (BO) is a popular method for computationally expensive black-box optimization. However, traditional BO methods need to solve new problems from scratch, leading to slow convergence. Recent studies try to extend BO to a transfer learning setup to speed up the optimization, where…

2024

Position: Rethinking Post-Hoc Search-Based Neural Approaches for Solving Large-Scale Traveling Salesman Problems

ICML 2024oral

Recent advancements in solving large-scale traveling salesman problems (TSP) utilize the heatmap-guided Monte Carlo tree search (MCTS) paradigm, where machine learning (ML) models generate heatmaps, indicating the probability distribution of each edge being part of the optimal solution, to guide MCT…

2024

Protecting Your LLMs with Information Bottleneck

NeurIPS 2024poster

The advent of large language models (LLMs) has revolutionized the field of natural language processing, yet they might be attacked to produce harmful content. Despite efforts to ethically align LLMs, these are often fragile and can be circumvented by jailbreaking attacks through optimized or manual…

2024

Stochastic Bayesian Optimization with Unknown Continuous Context Distribution via Kernel Density Estimation

AAAI 2024technical

Bayesian optimization (BO) is a sample-efficient method and has been widely used for optimizing expensive black-box functions. Recently, there has been a considerable interest in BO literature in optimizing functions that are affected by context variable in the environment, which is uncontrollable b…

2024

TimeX++: Learning Time-Series Explanations with Information Bottleneck

ICML 2024poster

Explaining deep learning models operating on time series data is crucial in various applications of interest which require interpretable and transparent insights from time series signals. In this work, we investigate this problem from an information theoretic perspective and show that most existing…

2024

Whittle Index with Multiple Actions and State Constraint for Inventory Management

ICLR 2024poster

Whittle index is a heuristic tool that leads to good performance for the restless bandits problem. In this paper, we extend Whittle index to a new multi-agent reinforcement learning (MARL) setting with multiple discrete actions and a possibly changing constraint on the state space, resulting in WIMS…

Cited by 11SourcePDFScholar
2023

H-TSP: Hierarchically Solving the Large-Scale Traveling Salesman Problem

AAAI 2023technical

We propose an end-to-end learning framework based on hierarchical reinforcement learning, called H-TSP, for addressing the large-scale Traveling Salesman Problem (TSP). The proposed H-TSP constructs a solution of a TSP instance starting from the scratch relying on two components: the upper-level pol…

2023

Pointerformer: Deep Reinforced Multi-Pointer Transformer for the Traveling Salesman Problem

AAAI 2023technical

Traveling Salesman Problem (TSP), as a classic routing optimization problem originally arising in the domain of transportation and logistics, has become a critical task in broader domains, such as manufacturing and biology. Recently, Deep Reinforcement Learning (DRL) has been increasingly employed t…

2023

Robust Situational Reinforcement Learning in Face of Context Disturbances

ICML 2023poster

In many real-world tasks, some parts of state features, called contexts, are independent of action signals, e.g., customer demand in inventory control, speed of lead car in autonomous driving, etc. One of the challenges of reinforcement learning in these applications is that the true context transit…

Cited by 4SourcePDFScholar
2023

Time-Varying Constraint-Driven Optimal Task Execution for Multiple Autonomous Underwater Vehicles

RA-L 2023

This letter focuses on the constraint-driven optimal control for multiple Autonomous Underwater Vehicles (AUVs). The different tasks are formulated as multiple constraints on optimization. First, the task goals are formulated by the time-varying control barrier functions. Then, a novel cost-to-const

Cited by 20SourceScholar
2022

Monte Carlo Tree Search based Variable Selection for High Dimensional Bayesian Optimization

NeurIPS 2022accept

Bayesian optimization (BO) is a class of popular methods for expensive black-box optimization, and has been widely applied to many scenarios. However, BO suffers from the curse of dimensionality, and scaling it to high-dimensional problems is still a challenge. In this paper, we propose a variable s…