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Xiangyu Liu

28 accepted papers

2026

Answering the Unanswerable Is to Err Knowingly: Analyzing and Mitigating Abstention Failures in Large Reasoning Models

AAAI 2026technical

Large reasoning models (LRMs) have shown remarkable progress on complex reasoning tasks. However, some questions posed to LRMs are inherently unanswerable, such as math problems lacking sufficient conditions. We find that LRMs continually fail to provide appropriate abstentions when confronted with

Cited by 0SourcePDFScholar
2026

ProtSAE: Disentangling and Interpreting Protein Language Models via Semantically-Guided Sparse Autoencoders

AAAI 2026technical

Sparse Autoencoder (SAE) has emerged as a powerful tool for mechanistic interpretability of large language models. Recent works apply SAE to protein language models (PLMs), aiming to extract and analyze biologically meaningful features from their latent spaces. However, SAE suffers from semantic en

Cited by 0SourcePDFScholar
2026

Scaling Inference-Time Computation via Opponent Simulation: Enabling Online Strategic Adaptation in Repeated Negotiation

ICML 2026poster

While large language models (LLMs) have emerged as powerful decision-makers across a wide range of single-agent and stationary environments, fewer efforts have been devoted to settings where LLMs must engage in \emph{repeated} and \emph{strategic} interactions with unknown or dynamic opponents. In s…

Cited by 0SourceScholar
2025

Avoiding Knowledge Edit Skipping in Multi-hop Question Answering with Guided Decomposition

EMNLP 2025

In a rapidly evolving world where information updates swiftly, knowledge in large language models (LLMs) becomes outdated quickly. Retraining LLMs is not a cost-effective option, making knowledge editing (KE) without modifying parameters particularly necessary. We find that although existing retriev

Cited by 0SourcePDFScholar
2025

Controllable Protein Sequence Generation with LLM Preference Optimization

AAAI 2025technical

Designing proteins with specific attributes offers an important solution to address biomedical challenges. Pre-trained protein large language models (LLMs) have shown promising results on protein sequence generation. However, to control sequence generation for specific attributes, existing work stil…

2025

Do LLM Agents Have Regret? A Case Study in Online Learning and Games

ICLR 2025poster

Large language models (LLMs) have been increasingly employed for (interactive) decision-making, via the development of LLM-based autonomous agents. Despite their emerging successes, the performance of LLM agents in decision-making has not been fully investigated through quantitative metrics, especia…

Cited by 20SourcePDFScholar
2025

Is Poisoning a Real Threat to DPO? Maybe More So Than You Think

AAAI 2025technical

Recent advancements in Reinforcement Learning with Human Feedback (RLHF) have significantly impacted the alignment of Large Language Models (LLMs). The sensitivity of reinforcement learning algorithms such as Proximal Policy Optimization (PPO) has led to new line work on Direct Preference Optimizati…

Cited by 0SourcePDFScholar
2025

Lunar Twins: We Choose to Go to the Moon with Large Language Models

ACL 2025finding

In recent years, the rapid advancement of large language models (LLMs) has significantly reshaped the landscape of scientific research. While LLMs have achieved notable success across various domains, their application in specialized fields such as lunar exploration remains underdeveloped, and their…

2025

MVBoost: Boost 3D Reconstruction with Multi-View Refinement

CVPR 2025poster

Recent advancements in 3D object reconstruction have been remarkable, yet most current 3D models rely heavily on existing 3D datasets. The scarcity of diverse 3D datasets results in limited generalization capabilities of 3D reconstruction models. In this paper, we propose a novel framework for boost…

2025

Mitigating Lost-in-Retrieval Problems in Retrieval Augmented Multi-Hop Question Answering

ACL 2025long

In this paper, we identify a critical problem, “lost-in-retrieval”, in retrieval-augmented multi-hop question answering (QA): the key entities are missed in LLMs’ sub-question decomposition. “Lost-in-retrieval” significantly degrades the retrieval performance, which disrupts the reasoning chain and…

2025

RAGRouter: Learning to Route Queries to Multiple Retrieval-Augmented Language Models

NeurIPS 2025poster

Retrieval-Augmented Generation (RAG) significantly improves the performance of Large Language Models (LLMs) on knowledge-intensive tasks. However, varying response quality across LLMs under RAG necessitates intelligent routing mechanisms, which select the most suitable model for each query from mult…

Cited by 0SourcecodeScholar
2024

Beyond Worst-case Attacks: Robust RL with Adaptive Defense via Non-dominated Policies

ICLR 2024spotlight

In light of the burgeoning success of reinforcement learning (RL) in diverse real-world applications, considerable focus has been directed towards ensuring RL policies are robust to adversarial attacks during test time. Current approaches largely revolve around solving a minimax problem to prepare f…

2024

Game-Theoretic Robust Reinforcement Learning Handles Temporally-Coupled Perturbations

ICLR 2024poster

Deploying reinforcement learning (RL) systems requires robustness to uncertainty and model misspecification, yet prior robust RL methods typically only study noise introduced independently across time. However, practical sources of uncertainty are usually coupled across time. We formally introduce t…

Cited by 7SourcePDFScholar
2024

Multi-Aspect Controllable Text Generation with Disentangled Counterfactual Augmentation

ACL 2024long

Multi-aspect controllable text generation aims to control the generated texts in attributes from multiple aspects (e.g., “positive” from sentiment and “sport” from topic). Existing works neglect attribute correlations formed by the intertwining of different attributes. Particularly, the stereotype f…

2024

Provable Partially Observable Reinforcement Learning with Privileged Information

NeurIPS 2024poster

Partial observability of the underlying states generally presents significant challenges for reinforcement learning (RL). In practice, certain *privileged information* , e.g., the access to states from simulators, has been exploited in training and achieved prominent empirical successes. To better u…

Cited by 2SourcePDFScholar
2024

Rethinking Adversarial Policies: A Generalized Attack Formulation and Provable Defense in RL

ICLR 2024poster

Most existing works focus on direct perturbations to the victim's state/action or the underlying transition dynamics to demonstrate the vulnerability of reinforcement learning agents to adversarial attacks. However, such direct manipulations may not be always realizable. In this paper, we consider…

Cited by 4SourcePDFScholar
2024

Weathering Ongoing Uncertainty: Learning and Planning in a Time-Varying Partially Observable Environment

ICRA 2024poster

Optimal decision-making presents a significant challenge for autonomous systems operating in uncertain, stochastic and time-varying environments. Environmental variability over time can significantly impact the system’s optimal decision making strategy for mission completion. To model such environme…

Cited by 3SourceScholar
2023

Bayes-MIL: A New Probabilistic Perspective on Attention-based Multiple Instance Learning for Whole Slide Images

ICLR 2023poster

Multiple instance learning (MIL) is a popular weakly-supervised learning model on the whole slide image (WSI) for AI-assisted pathology diagnosis. The recent advance in attention-based MIL allows the model to find its region-of-interest (ROI) for interpretation by learning the attention weights for…

Cited by 20SourcePDFScholar
2023

Partially Observable Multi-agent RL with (Quasi-)Efficiency: The Blessing of Information Sharing

ICML 2023poster

We study provable multi-agent reinforcement learning (MARL) in the general framework of partially observable stochastic games (POSGs). To circumvent the known hardness results and the use of computationally intractable oracles, we propose to leverage the potential *information-sharing* among agents,…

Cited by 10SourcePDFScholar
2022

RoChBert: Towards Robust BERT Fine-tuning for Chinese

EMNLP 2022finding

Despite of the superb performance on a wide range of tasks, pre-trained language models (e.g., BERT) have been proved vulnerable to adversarial texts. In this paper, we present RoChBERT, a framework to build more Robust BERT-based models by utilizing a more comprehensive adversarial graph to fuse Ch…

2022

SemAttack: Natural Textual Attacks via Different Semantic Spaces

NAACL 2022findings

Recent studies show that pre-trained language models (LMs) are vulnerable to textual adversarial attacks. However, existing attack methods either suffer from low attack success rates or fail to search efficiently in the exponentially large perturbation space. We propose an efficient and effective fr…

2021

Counterfactual Adversarial Learning with Representation Interpolation

EMNLP 2021finding

Deep learning models exhibit a preference for statistical fitting over logical reasoning. Spurious correlations might be memorized when there exists statistical bias in training data, which severely limits the model performance especially in small data scenarios. In this work, we introduce Counterfa…

2021

Coxgraph: Multi-Robot Collaborative, Globally Consistent, Online Dense Reconstruction System

IROS 2021poster

Real-time dense reconstruction has been extensively studied for its wide applications in computer vision and robotics, meanwhile much effort has been made for the multi-robot system which plays an irreplaceable role in complicated but time-critical scenarios, e.g., search and rescue tasks. In this p…

Cited by 14SourceScholar
2021

Enhancing Model Robustness by Incorporating Adversarial Knowledge into Semantic Representation

ICASSP 2021accepted

Despite that deep neural networks (DNNs) have achieved enormous success in many domains like natural language processing (NLP), they have also been proven to be vulnerable to maliciously generated adversarial examples. Such inherent vulnerability has threatened various real-world deployed DNNs-based…

Cited by 0SourceScholar
2021

Towards Unifying Behavioral and Response Diversity for Open-ended Learning in Zero-sum Games

NeurIPS 2021poster

Measuring and promoting policy diversity is critical for solving games with strong non-transitive dynamics where strategic cycles exist, and there is no consistent winner (e.g., Rock-Paper-Scissors). With that in mind, maintaining a pool of diverse policies via open-ended learning is an attractive s…