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Pengfei Cao

51 accepted papers

2026

Bias-Restrained Prefix Representation Finetuning for Mathematical Reasoning

AAAI 2026technical

Parameter-Efficient finetuning (PEFT) enhances model performance on downstream tasks by updating a minimal subset of parameters. Representation finetuning (ReFT) methods further improve efficiency by freezing model weights and optimizing internal representations with fewer parameters than PEFT, outp

Cited by 0SourcePDFScholar
2026

Fixing the Broken Compass: Diagnosing and Improving Inference-Time Reward Modeling

ICLR 2026poster

Inference-time scaling techniques have shown promise in enhancing the reasoning capabilities of large language models (LLMs). While recent research has primarily focused on training-time optimization, our work highlights inference-time reward model (RM)-based reasoning as a critical yet overlooked a…

Cited by 0SourcecodeScholar
2026

MMR-Life: Piecing Together Real-life Scenes for Multimodal Multi-image Reasoning

ICLR 2026poster

Recent progress in the reasoning capabilities of multimodal large language models (MLLMs) has empowered them to address more complex tasks such as scientific analysis and mathematical reasoning. Despite their promise, MLLMs’ reasoning abilities across different scenarios in real life remain largely…

Cited by 0SourcecodeScholar
2026

MMR-V: What's Left Unsaid? A Benchmark for Multimodal Deep Reasoning in Videos

ICLR 2026poster

The sequential structure of videos poses a challenge to the ability of multimodal large language models (MLLMs) to locate multi-frame evidence and conduct multimodal reasoning. However, existing video benchmarks mainly focus on understanding tasks, which only require models to match frames mentioned…

Cited by 0SourcecodeScholar
2026

Omni-Reward: Towards Generalist Omni-Modal Reward Modeling with Free-Form Preferences

ICLR 2026oral

Reward models (RMs) play a critical role in aligning AI behaviors with human preferences, yet they face two fundamental challenges: (1) Modality Imbalance, where most RMs are mainly focused on text and image modalities, offering limited support for video, audio, and other modalities; and (2) Prefere…

Cited by 0SourcecodeScholar
2025

A Troublemaker with Contagious Jailbreak Makes Chaos in Honest Towns

ACL 2025long

With the development of large language models, they are widely used as agents in various fields. A key component of agents is memory, which stores vital information but is susceptible to jailbreak attacks. Existing research mainly focuses on single-agent attacks and shared memory attacks. However, r…

Cited by 0SourcePDFScholar
2025

Agent-RewardBench: Towards a Unified Benchmark for Reward Modeling across Perception, Planning, and Safety in Real-World Multimodal Agents

ACL 2025long

As Multimodal Large Language Models (MLLMs) advance, multimodal agents show promise in real-world tasks like web navigation and embodied intelligence. However, due to limitations in a lack of external feedback, these agents struggle with self-correction and generalization. A promising approach is to…

2025

Beyond Under-Alignment: Atomic Preference Enhanced Factuality Tuning for Large Language Models

NAACL 2025findings

Large language models (LLMs) have achieved remarkable success but still tend to generate factually erroneous responses, a phenomenon known as hallucination. A recent trend is to use preference learning to fine-tune models to align with factuality. However, existing work primarily evaluates fine-tune…

2025

CITI: Enhancing Tool Utilizing Ability in Large Language Models Without Sacrificing General Performance

AAAI 2025technical

Tool learning enables Large Language Models (LLMs) to interact with the external environment by invoking tools, enriching the accuracy and capability scope of LLMs. However, previous works predominantly focus on improving the model's tool-utilizing accuracy and the ability to generalize to new, unse…

2025

Cracking Factual Knowledge: A Comprehensive Analysis of Degenerate Knowledge Neurons in Large Language Models

ACL 2025long

Knowledge neuron theory provides a key approach to understanding the mechanisms of factual knowledge in Large Language Models (LLMs), which suggests that facts are stored within multi-layer perceptron neurons. This paper further explores **Degenerate Knowledge Neurons** (DKNs), where distinct sets o…

Cited by 4SourcePDFScholar
2025

Evaluating Personalized Tool-Augmented LLMs from the Perspectives of Personalization and Proactivity

ACL 2025long

Personalized tool utilization is essential for aligning large language models (LLMs) with user preference in interaction scenarios with various tools. However, most of the current benchmarks primarily focus on either personalization of text generation or direct tool-utilizing, without considering bo…

2025

Knowledge Localization: Mission Not Accomplished? Enter Query Localization!

ICLR 2025spotlight

Large language models (LLMs) store extensive factual knowledge, but the mechanisms behind how they store and express this knowledge remain unclear. The Knowledge Neuron (KN) thesis is a prominent theory for explaining these mechanisms. This theory is based on the **Knowledge Localization (KL)** assu…

Cited by 4SourcePDFScholar
2025

Knowledge in Superposition: Unveiling the Failures of Lifelong Knowledge Editing for Large Language Models

AAAI 2025technical

Knowledge editing aims to update outdated or incorrect knowledge in large language models (LLMs). However, current knowledge editing methods have limited scalability for lifelong editing. This study explores the fundamental reason why knowledge editing fails in lifelong editing. We begin with the cl…

2025

M2Edit: Locate and Edit Multi-Granularity Knowledge in Multimodal Large Language Model

EMNLP 2025

Multimodal knowledge editing is an important method for modifying outdated or incorrect knowledge in Multimodal Large Language Models (MLLMs). However, existing datasets for multimodal knowledge editing lack multi-granularity knowledge. In this paper, we present a more realistic dataset called M2Edi

2025

MIRAGE: Evaluating and Explaining Inductive Reasoning Process in Language Models

ICLR 2025poster

Inductive reasoning is an essential capability for large language models (LLMs) to achieve higher intelligence, which requires the model to generalize rules from observed facts and then apply them to unseen examples. We present {\scshape Mirage}, a synthetic dataset that addresses the limitations of…

Cited by 3SourcePDFScholar
2025

RAG-RewardBench: Benchmarking Reward Models in Retrieval Augmented Generation for Preference Alignment

ACL 2025finding

Despite the significant progress made by existing retrieval augmented language models (RALMs) in providing trustworthy responses and grounding in reliable sources, they often overlook effective alignment with human preferences. In the alignment process, reward models (RMs) act as a crucial proxy for…

2025

Revealing the Deceptiveness of Knowledge Editing: A Mechanistic Analysis of Superficial Editing

ACL 2025long

Knowledge editing, which aims to update the knowledge encoded in language models, can be deceptive. Despite the fact that many existing knowledge editing algorithms achieve near-perfect performance on conventional metrics, the models edited by them are still prone to generating original knowledge. T…

2025

The Knowledge Microscope: Features as Better Analytical Lenses than Neurons

ACL 2025long

We demonstrate that features, rather than neurons, serve as superior analytical units for understanding the mechanisms of factual knowledge in Language Models (LMs). Previous studies primarily utilize MLP neurons as units of analysis; however, neurons suffer from polysemanticity, leading to limited…

Cited by 0SourcePDFScholar
2025

Towards Better Chain-of-Thought: A Reflection on Effectiveness and Faithfulness

ACL 2025finding

Chain-of-thought (CoT) prompting demonstrates varying performance under different reasoning tasks.Previous work attempts to evaluate it but falls short in providing an in-depth analysis of patterns that influence the CoT. In this paper, we study the CoT performance from the perspective of effectiven…

2025

Towards Robust Knowledge Unlearning: An Adversarial Framework for Assessing and Improving Unlearning Robustness in Large Language Models

AAAI 2025technical

LLM have achieved success in many fields but still troubled by problematic content in the training corpora. LLM unlearning aims at reducing their influence and avoid undesirable behaviours. However, existing unlearning methods remain vulnerable to adversarial queries and the unlearned knowledge resu…

Cited by 7SourcePDFScholar
2024

AgentsCourt: Building Judicial Decision-Making Agents with Court Debate Simulation and Legal Knowledge Augmentation

EMNLP 2024finding

With the development of deep learning, natural language processing technology has effectively improved the efficiency of various aspects of the traditional judicial industry. However, most current efforts focus on tasks within individual judicial stages, making it difficult to handle complex tasks t…

2024

Continual Few-shot Event Detection via Hierarchical Augmentation Networks

COLING 2024main

Traditional continual event detection relies on abundant labeled data for training, which is often impractical to obtain in real-world applications. In this paper, we introduce continual few-shot event detection (CFED), a more commonly encountered scenario when a substantial number of labeled sample…

2024

Cutting Off the Head Ends the Conflict: A Mechanism for Interpreting and Mitigating Knowledge Conflicts in Language Models

ACL 2024findings

Recently, retrieval augmentation and tool augmentation have demonstrated a remarkable capability to expand the internal memory boundaries of language models (LMs) by providing external context. However, internal memory and external context inevitably clash, leading to knowledge conflicts within LMs.…

2024

Focus on Your Question! Interpreting and Mitigating Toxic CoT Problems in Commonsense Reasoning

ACL 2024long

Large language models exhibit high-level commonsense reasoning abilities, especially with enhancement methods like Chain-of-Thought (CoT). However, we find these CoT-like methods lead to a considerable number of originally correct answers turning wrong, which we define as the Toxic CoT problem. To i…

2024

Journey to the Center of the Knowledge Neurons: Discoveries of Language-Independent Knowledge Neurons and Degenerate Knowledge Neurons

AAAI 2024technical

Pre-trained language models (PLMs) contain vast amounts of factual knowledge, but how the knowledge is stored in the parameters remains unclear. This paper delves into the complex task of understanding how factual knowledge is stored in multilingual PLMs, and introduces the Architecture-adapted Mult…

2024

LINKED: Eliciting, Filtering and Integrating Knowledge in Large Language Model for Commonsense Reasoning

EMNLP 2024finding

Large language models (LLMs) sometimes demonstrate poor performance on knowledge-intensive tasks, commonsense reasoning is one of them. Researchers typically address these issues by retrieving related knowledge from knowledge graphs or employing self-enhancement methods to elicit knowledge in LLMs.…

2024

Leros: Learning Explicit Reasoning on Synthesized Data for Commonsense Question Answering

COLING 2024main

Recent work shows large language models can be prompted to generate useful rationales for commonsense question answering (CQA), which can improve the performance of both themselves and other models. However, the cost of deployment and further tuning is relatively expensive for the large models. Some…

2024

MULFE: A Multi-Level Benchmark for Free Text Model Editing

ACL 2024long

Adjusting the outdated behaviors of large langugae models (LLMs) after deployment remains a significant challenge. It motivates the model editing research, which is however mainly explored in a restricted task form with triple-based edit requests. Recent works have initiated a transition to a more p…

2024

Oasis: Data Curation and Assessment System for Pretraining of Large Language Models

IJCAI 2024poster

Data is one of the most critical elements in building a large language model. However, existing systems either fail to customize a corpus curation pipeline or neglect to leverage comprehensive corpus assessment for iterative optimization of the curation. To this end, we present a pretraining corpus…

2024

RWKU: Benchmarking Real-World Knowledge Unlearning for Large Language Models

NeurIPS 2024poster

Large language models (LLMs) inevitably memorize sensitive, copyrighted, and harmful knowledge from the training corpus; therefore, it is crucial to erase this knowledge from the models. Machine unlearning is a promising solution for efficiently removing specific knowledge by post hoc modifying mode…

2024

Tug-of-War between Knowledge: Exploring and Resolving Knowledge Conflicts in Retrieval-Augmented Language Models

COLING 2024main

Retrieval-augmented language models (RALMs) have demonstrated significant potential in refining and expanding their internal memory by retrieving evidence from external sources. However, RALMs will inevitably encounter knowledge conflicts when integrating their internal memory with external sources.…

2024

Unlocking the Future: Exploring Look-Ahead Planning Mechanistic Interpretability in Large Language Models

EMNLP 2024main

Planning, as the core module of agents, is crucial in various fields such as embodied agents, web navigation, and tool using. With the development of large language models (LLMs), some researchers treat large language models as intelligent agents to stimulate and evaluate their planning capabilities…

2024

Whispers that Shake Foundations: Analyzing and Mitigating False Premise Hallucinations in Large Language Models

EMNLP 2024main

Large Language Models (LLMs) have shown impressive capabilities but still suffer from the issue of hallucinations. A significant type of this issue is the false premise hallucination, which we define as the phenomenon when LLMs generate hallucinated text when confronted with false premise questions.…

Cited by 6SourcePDFScholar
2024

WilKE: Wise-Layer Knowledge Editor for Lifelong Knowledge Editing

ACL 2024findings

Knowledge editing aims to rectify inaccuracies in large language models (LLMs) without costly retraining for outdated or erroneous knowledge. However, current knowledge editing methods primarily focus on single editing, failing to meet the requirements for lifelong editing. This study reveals a perf…

2024

Zero-Shot Cross-Lingual Document-Level Event Causality Identification with Heterogeneous Graph Contrastive Transfer Learning

COLING 2024main

Event Causality Identification (ECI) refers to the detection of causal relations between events in texts. However, most existing studies focus on sentence-level ECI with high-resource languages, leaving more challenging document-level ECI (DECI) with low-resource languages under-explored. In this pa…

2024

ZhuJiu-Knowledge: A Fairer Platform for Evaluating Multiple Knowledge Types in Large Language Models

NAACL 2024system demonstrations

The swift advancement in large language models (LLMs) has heightened the importance of model evaluations. LLMs have acquired a substantial amount of knowledge, and evaluating the knowledge of these LLMs is crucial. To address this, we introduce the ZhuJiu-Knowledge benchmark which carefully consider…

Cited by 1SourcePDFScholar
2023

Alignment Precedes Fusion: Open-Vocabulary Named Entity Recognition as Context-Type Semantic Matching

EMNLP 2023long findings

Despite the significant progress in developing named entity recognition models, scaling to novel-emerging types still remains challenging in real-world scenarios. Continual learning and zero-shot learning approaches have been explored to handle novel-emerging types with less human supervision, but t…

Cited by 0SourceScholar
2023

Complex Event Schema Induction with Knowledge-Enriched Diffusion Model

EMNLP 2023long findings

The concept of a complex event schema pertains to the graph structure that represents real-world knowledge of events and their multi-dimensional relationships. However, previous studies on event schema induction have been hindered by challenges such as error propagation and data quality issues. To t…

Cited by 0SourceScholar
2023

Event Ontology Completion with Hierarchical Structure Evolution Networks

EMNLP 2023long main

Traditional event detection methods require predefined event schemas. However, manually defining event schemas is expensive and the coverage of schemas is limited. To this end, some works study the event type induction (ETI) task, which discovers new event types via clustering. However, the setting…

Cited by 0SourceScholar
2023

InstructoR: Instructing Unsupervised Conversational Dense Retrieval with Large Language Models

EMNLP 2023long findings

Compared to traditional single-turn ad-hoc retrieval, conversational retrieval needs to handle the multi-turn conversation and understand the user’s real query intent. However, most existing methods simply fine-tune the pre-trained ad-hoc retriever on limited supervised data, making it challenging f…

Cited by 0SourcecodeScholar
2023

LEGO: A Multi-agent Collaborative Framework with Role-playing and Iterative Feedback for Causality Explanation Generation

EMNLP 2023long findings

Causality Explanation Generation refers to generate an explanation in natural language given an initial cause-effect pair. It demands rigorous explicit rationales to demonstrate the acquisition of implicit commonsense knowledge, which is unlikely to be easily memorized, making it challenging for lar…

Cited by 0SourceScholar
2023

Zero-Shot Cross-Lingual Event Argument Extraction with Language-Oriented Prefix-Tuning

AAAI 2023technical

Event argument extraction (EAE) aims to identify the arguments of a given event, and classify the roles that those arguments play. Due to high data demands of training EAE models, zero-shot cross-lingual EAE has attracted increasing attention, as it greatly reduces human annotation effort. Some prio…

2022

A Good Neighbor, A Found Treasure: Mining Treasured Neighbors for Knowledge Graph Entity Typing

EMNLP 2022main

The task of knowledge graph entity typing (KGET) aims to infer the missing types for entities in knowledge graphs. Some pioneering work has proved that neighbor information is very important for the task. However, existing methods only leverage the one-hop neighbor information of the central entity,…

2021

Automatic ICD Coding via Interactive Shared Representation Networks with Self-distillation Mechanism

ACL 2021long

The ICD coding task aims at assigning codes of the International Classification of Diseases in clinical notes. Since manual coding is very laborious and prone to errors, many methods have been proposed for the automatic ICD coding task. However, existing works either ignore the long-tail of code fre…

2021

Domain-Lifelong Learning for Dialogue State Tracking via Knowledge Preservation Networks

EMNLP 2021main

Dialogue state tracking (DST), which estimates user goals given a dialogue context, is an essential component of task-oriented dialogue systems. Conventional DST models are usually trained offline, which requires a fixed dataset prepared in advance. This paradigm is often impractical in real-world a…

2021

Knowledge-Enriched Event Causality Identification via Latent Structure Induction Networks

ACL 2021long

Identifying causal relations of events is an important task in natural language processing area. However, the task is very challenging, because event causality is usually expressed in diverse forms that often lack explicit causal clues. Existing methods cannot handle well the problem, especially in…

Cited by 80SourcePDFScholar
2021

LearnDA: Learnable Knowledge-Guided Data Augmentation for Event Causality Identification

ACL 2021long

Modern models for event causality identification (ECI) are mainly based on supervised learning, which are prone to the data lacking problem. Unfortunately, the existing NLP-related augmentation methods cannot directly produce available data required for this task. To solve the data lacking problem,…

Cited by 64SourcePDFScholar
2021

Uncertain Local-to-Global Networks for Document-Level Event Factuality Identification

EMNLP 2021main

Event factuality indicates the degree of certainty about whether an event occurs in the real world. Existing studies mainly focus on identifying event factuality at sentence level, which easily leads to conflicts between different mentions of the same event. To this end, we study the problem of docu…