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Xiusi Chen

20 accepted papers

2026

Beyond Log Likelihood: Probability-Based Objectives for Supervised Fine-Tuning across the Model Capability Continuum

ICML 2026spotlight

Supervised fine-tuning (SFT) is the standard approach for post-training large language models (LLMs), yet it often shows limited generalization. We trace this limitation to its default training objective: negative log likelihood (NLL). While NLL is classically optimal when training from scratch, pos…

Cited by 0SourceScholar
2026

How Far Can Unsupervised RLVR Scale LLM Training?

ICLR 2026poster

Unsupervised Reinforcement Learning with Verifiable Rewards (URLVR) offers a pathway for Large Language Models (LLMs) to improve without human supervision. Particularly, many works use model intrinsic information as rewards for URLVR, showing promising improvements, yet their potential and limitatio…

Cited by 0SourceScholar
2026

Perception-Aware Policy Optimization for Multimodal Reasoning

ICLR 2026poster

Reinforcement Learning with Verifiable Rewards (RLVR) has proven to be a highly effective strategy for empowering Large Language Models (LLMs) with long chain-of-thought reasoning abilities. However, its design and optimizations remain tailored to purely textual domains, resulting in suboptimal perf…

Cited by 0SourcecodeScholar
2025

DecisionFlow: Advancing Large Language Model as Principled Decision Maker

EMNLP 2025

In high-stakes domains such as healthcare and finance, effective decision-making demands not just accurate outcomes but transparent and explainable reasoning. However, current language models often lack the structured deliberation needed for such tasks, instead generating decisions and justification

2025

EscapeBench: Towards Advancing Creative Intelligence of Language Model Agents

ACL 2025long

Language model agents excel in long-session planning and reasoning, but existing benchmarks primarily focus on goal-oriented tasks with explicit objectives, neglecting creative adaptation in unfamiliar environments. To address this, we introduce EscapeBench—a benchmark suite of room escape game envi…

2025

ModelingAgent: Bridging LLMs and Mathematical Modeling for Real-World Challenges

EMNLP 2025

Recent progress in large language models (LLMs) has enabled substantial advances in solving mathematical problems. However, existing benchmarks often fail to reflect real-world complexity, which demand open-ended, interdisciplinary reasoning and integration of computational tools. To address this ga

2025

Profiling LLM’s Copyright Infringement Risks under Adversarial Persuasive Prompting

EMNLP 2025

Large Language Models (LLMs) have demonstrated impressive capabilities in text generation but raise concerns regarding potential copyright infringement. While prior research has explored mitigation strategies like content filtering and alignment, the impact of adversarial persuasion techniques in el

2025

SMART: Self-Aware Agent for Tool Overuse Mitigation

ACL 2025finding

Current Large Language Model (LLM) agents demonstrate strong reasoning and tool use capabilities, but often lack self-awareness, failing to balance these approaches effectively. This imbalance leads to **Tool Overuse**, where models unnecessarily rely on external tools for tasks solvable with parame…

2025

SafeSwitch: Steering Unsafe LLM Behavior via Internal Activation Signals

EMNLP 2025

Large language models (LLMs) exhibit exceptional capabilities across various tasks but also pose risks by generating harmful content. Existing safety mechanisms, while improving model safety, often lead to overly cautious behavior and fail to fully leverage LLMs’ internal cognitive processes. Inspir

2025

Self-Updatable Large Language Models by Integrating Context into Model Parameters

ICLR 2025poster

Despite significant advancements in large language models (LLMs), the rapid and frequent integration of small-scale experiences, such as interactions with sur- rounding objects, remains a substantial challenge. Two critical factors in assimilating these experiences are (1) **Efficacy**: the ability…

Cited by 0SourcePDFScholar
2025

Semi-supervised Fine-tuning for Large Language Models

NAACL 2025findings

Supervised fine-tuning (SFT) is crucial in adapting large language models (LLMs) to a specific domain or task. However, only a limited amount of labeled data is available in practical applications, which poses a severe challenge for SFT in yielding satisfactory results. Therefore, a data-efficient f…

2025

Strategist: Self-improvement of LLM Decision Making via Bi-Level Tree Search

ICLR 2025poster

Traditional reinforcement learning and planning require a lot of data and training to develop effective strategies. On the other hand, large language models (LLMs) can generalize well and perform tasks without prior training but struggle with complex planning and decision-making. We introduce **STRA…

Cited by 0SourcePDFScholar
2025

ToolRL: Reward is All Tool Learning Needs

NeurIPS 2025poster

Current Large Language Models (LLMs) often undergo supervised fine-tuning (SFT) to acquire tool use capabilities. However, SFT struggles to generalize to unfamiliar or complex tool use scenarios. Recent advancements in reinforcement learning (RL), particularly with R1-like models, have demonstrated…

Cited by 0SourcecodeScholar
2024

A Comprehensive Survey of Scientific Large Language Models and Their Applications in Scientific Discovery

EMNLP 2024main

In many scientific fields, large language models (LLMs) have revolutionized the way text and other modalities of data (e.g., molecules and proteins) are handled, achieving superior performance in various applications and augmenting the scientific discovery process. Nevertheless, previous surveys on…

2024

IterAlign: Iterative Constitutional Alignment of Large Language Models

NAACL 2024long

With the rapid development of large language models (LLMs), aligning LLMs with human values and societal norms to ensure their reliability and safety has become crucial. Reinforcement learning with human feedback (RLHF) and Constitutional AI (CAI) have been proposed for LLM alignment. However, these…

2024

Language Models as Semantic Indexers

ICML 2024poster

Semantic identifier (ID) is an important concept in information retrieval that aims to preserve the semantics of objects such as documents and items inside their IDs. Previous studies typically adopt a two-stage pipeline to learn semantic IDs by first procuring embeddings using off-the-shelf text en…

2024

MEMORYLLM: Towards Self-Updatable Large Language Models

ICML 2024poster

Existing Large Language Models (LLMs) usually remain static after deployment, which might make it hard to inject new knowledge into the model. We aim to build models containing a considerable portion of self-updatable parameters, enabling the model to integrate new knowledge effectively and efficien…

2024

MinPrompt: Graph-based Minimal Prompt Data Augmentation for Few-shot Question Answering

ACL 2024long

Recent advances in few-shot question answering (QA) mostly rely on the power of pre-trained large language models (LLMs) and fine-tuning in specific settings. Although the pre-training stage has already equipped LLMs with powerful reasoning capabilities, LLMs still need to be fine-tuned to adapt to…

Cited by 16SourcePDFScholar