Mengshu Sun
2026
Collaboration of Fusion and Independence: Hypercomplex-driven Robust Multi-Modal Knowledge Graph Completion
Zhiqiang Liu | Yichi Zhang | Mengshu Sun | Lei Liang | Wen Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Zhiqiang Liu | Yichi Zhang | Mengshu Sun | Lei Liang | Wen Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Multi-modal knowledge graph completion (MMKGC) aims to discover missing facts in multi-modal knowledge graphs (MMKGs) by leveraging both structural relationships and diverse modality information of entities. Existing MMKGC methods follow two multi-modal paradigms: fusion-based and ensemble-based. Fusion-based methods employ fixed fusion strategies, which inevitably leads to the loss of modality-specific information and a lack of flexibility to adapt to varying modality relevance across contexts. In contrast, ensemble-based methods retain modality independence through dedicated sub-models but struggle to capture the nuanced, context-dependent semantic interplay between modalities. To overcome these dual limitations, we propose a novel MMKGC method M-Hyper, which achieves the coexistence and collaboration of fused and independent modality representations. Our method integrates the strengths of both paradigms, enabling effective cross-modal interactions while maintaining modality-specific information. Inspired by “quaternion” algebra, we utilize its four orthogonal bases to represent multiple independent modalities and employ the Hamilton product to efficiently model pair-wise interactions among them. Specifically, we introduce a Fine-grained Entity Representation Factorization (FERF) module and a Robust Relation-aware Modality Fusion (R2MF) module to obtain robust representations for three independent modalities and one fused modality. The resulting four modality representations are then mapped to the four orthogonal bases of a biquaternion for comprehensive modality interaction. Extensive experiments indicate its state-of-the-art performance with better robustness.
Sparse-RL: Breaking the Memory Wall in LLM Reinforcement Learning via Stable Sparse Rollouts
Sijia Luo | Xiaokang Zhang | Yuxuan Hu | Bohan Zhang | Ke Wang | Jinbo Su | Mengshu Sun | Lei Liang | Jing Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Sijia Luo | Xiaokang Zhang | Yuxuan Hu | Bohan Zhang | Ke Wang | Jinbo Su | Mengshu Sun | Lei Liang | Jing Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Reinforcement Learning (RL) has become essential for eliciting complex reasoning capabilities in Large Language Models (LLMs). However, the substantial memory overhead of storing Key-Value (KV) caches during long-horizon rollouts acts as a critical bottleneck, often prohibiting efficient training on limited hardware. While existing KV compression techniques offer a remedy for inference, directly applying them to RL training induces a severe policy mismatch, leading to catastrophic performance collapse. To address this, we introduce Sparse-RL, which empowers stable RL training under sparse rollouts. We show that instability arises from a fundamental policy mismatch among the dense old policy, the sparse sampler policy, and the learner policy. To mitigate this issue, Sparse-RL incorporates Sparsity-Aware Rejection Sampling and Importance-based Reweighting to correct the off-policy bias introduced by compression-induced information loss. Experimental results show that Sparse-RL reduces rollout overhead compared to dense baselines while preserving the performance. Furthermore, Sparse-RL inherently implements sparsity-aware training, significantly enhancing model robustness during sparse inference deployment.
Know the Known and the Unknown: Reasonable Answer Generation with Knowledge-Informed Citations
Yichi Zhang | Zhuo Chen | Lingbing Guo | Jun Xu | Mengshu Sun | Zhizhen Liu | Lei Liang | Wen Zhang | Huajun Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yichi Zhang | Zhuo Chen | Lingbing Guo | Jun Xu | Mengshu Sun | Zhizhen Liu | Lei Liang | Wen Zhang | Huajun Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Question answering (QA) with reference texts is a classic application scenario for large language models (LLMs), where high standards for the credibility and traceability of generated answers are crucial. Many existing approaches focus on generating multi-level citations linked to specific references within the answer, making it verifiable and trustworthy. However, they often overlook key challenges such as citation granularity, the awareness of unknown information, and the adoption of effective training strategies. In this paper, we introduce Knowledge-informed Citation (KFC), which addresses these issues through a novel data construction pipeline, a new benchmark, and an innovative training strategy. With approximately 42K samples spanning 19 distinct domains, KFC includes both traditional citations referencing known entity-level information and specialized citations referring to unknown knowledge in the given question. This structure provides a more granular approach to citations, guiding the model to recognize and explicitly indicate unknown information, thus enhancing the quality and credibility of the response. Additionally, we propose a self-correction paradigm, Self-KFC, designed to fine-tune LLMs by refining poorly cited answers into more accurate ones, making it particularly suitable for citation-dependent scenarios. We present comprehensive experimental results to demonstrate the effectiveness and generalization of Self-KFC on the KFC benchmark.
2025
SKA-Bench: A Fine-Grained Benchmark for Evaluating Structured Knowledge Understanding of LLMs
Zhiqiang Liu | Enpei Niu | Yin Hua | Mengshu Sun | Lei Liang | Huajun Chen | Wen Zhang
Findings of the Association for Computational Linguistics: EMNLP 2025
Zhiqiang Liu | Enpei Niu | Yin Hua | Mengshu Sun | Lei Liang | Huajun Chen | Wen Zhang
Findings of the Association for Computational Linguistics: EMNLP 2025
Although large language models (LLMs) have made significant progress in understanding Structured Knowledge (SK) like KG and Table, existing evaluations for SK understanding are non-rigorous (i.e., lacking evaluations of specific capabilities) and focus on a single type of SK. Therefore, we aim to propose a more comprehensive and rigorous structured knowledge understanding benchmark to diagnose the shortcomings of LLMs. In this paper, we introduce SKA-Bench, a Structured Knowledge Augmented QA Benchmark that encompasses four widely used structured knowledge forms: KG, Table, KG+Text, and Table+Text. We utilize a three-stage pipeline to construct SKA-Bench instances, which includes a question, an answer, positive knowledge units, and noisy knowledge units. To evaluate the SK understanding capabilities of LLMs in a fine-grained manner, we expand the instances into four fundamental ability testbeds: Noise Robustness, Order Insensitivity, Information Integration, and Negative Rejection. Empirical evaluations on 8 representative LLMs, including the advanced DeepSeek-R1, indicate that existing LLMs still face significant challenges in understanding structured knowledge, and their performance is influenced by factors such as the amount of noise, the order of knowledge units, and hallucination phenomenon. Our dataset and code are available at https://github.com/zjukg/SKA-Bench.
Have We Designed Generalizable Structural Knowledge Promptings? Systematic Evaluation and Rethinking
Yichi Zhang | Zhuo Chen | Lingbing Guo | Yajing Xu | Shaokai Chen | Mengshu Sun | Binbin Hu | Zhiqiang Zhang | Lei Liang | Wen Zhang | Huajun Chen
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Yichi Zhang | Zhuo Chen | Lingbing Guo | Yajing Xu | Shaokai Chen | Mengshu Sun | Binbin Hu | Zhiqiang Zhang | Lei Liang | Wen Zhang | Huajun Chen
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) have demonstrated exceptional performance in text generation within current NLP research. However, the lack of factual accuracy is still a dark cloud hanging over the LLM skyscraper. Structural knowledge prompting (SKP) is a prominent paradigm to integrate external knowledge into LLMs by incorporating structural representations, achieving state-of-the-art results in many knowledge-intensive tasks. However, existing methods often focus on specific problems, lacking a comprehensive exploration of the generalization and capability boundaries of SKP. This paper aims to evaluate and rethink the generalization capability of the SKP paradigm from four perspectives including Granularity, Transferability, Scalability, and Universality. To provide a thorough evaluation, we introduce a novel multi-granular, multi-level benchmark called SUBARU, consisting of 9 different tasks with varying levels of granularity and difficulty. Through extensive experiments, we draw key conclusions regarding the generalization of SKP, offering insights to guide the future development and extension of the SKP paradigm.
LightThinker: Thinking Step-by-Step Compression
Jintian Zhang | Yuqi Zhu | Mengshu Sun | Yujie Luo | Shuofei Qiao | Lun Du | Da Zheng | Huajun Chen | Ningyu Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Jintian Zhang | Yuqi Zhu | Mengshu Sun | Yujie Luo | Shuofei Qiao | Lun Du | Da Zheng | Huajun Chen | Ningyu Zhang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Large language models (LLMs) have shown remarkable performance in complex reasoning tasks, but their efficiency is hindered by the substantial memory and computational costs associated with generating lengthy tokens. In this paper, we propose LightThinker, a novel method that enables LLMs to dynamically compress intermediate thoughts during reasoning. Inspired by human cognitive processes, LightThinker compresses verbose thought steps into compact representations and discards the original reasoning chains, thereby significantly reducing the number of tokens stored in the context window.This is achieved by training the model on when and how to perform compression through data construction, mapping hidden states to condensed gist tokens, and creating specialized attention masks. Additionally, we introduce the Dependency (Dep) metric to quantify the degree of compression by measuring the reliance on historical tokens during generation. Extensive experiments on four datasets and two models show that LightThinker reduces peak memory usage and inference time, while maintaining competitive accuracy. Our work provides a new direction for improving the efficiency of LLMs in complex reasoning tasks without sacrificing performance.
2024
Continual Few-shot Event Detection via Hierarchical Augmentation Networks
Chenlong Zhang | Pengfei Cao | Yubo Chen | Kang Liu | Zhiqiang Zhang | Mengshu Sun | Jun Zhao
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
Chenlong Zhang | Pengfei Cao | Yubo Chen | Kang Liu | Zhiqiang Zhang | Mengshu Sun | Jun Zhao
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
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 samples are not accessible. The CFED task is challenging as it involves memorizing previous event types and learning new event types with few-shot samples. To mitigate these challenges, we propose a memory-based framework: Hierarchical Augmentation Network (HANet). To memorize previous event types with limited memory, we incorporate prototypical augmentation into the memory set. For the issue of learning new event types in few-shot scenarios, we propose a contrastive augmentation module for token representations. Despite comparing with previous state-of-the-art methods, we also conduct comparisons with ChatGPT. Experiment results demonstrate that our method significantly outperforms all of these methods in multiple continual few-shot event detection tasks.
OneGen: Efficient One-Pass Unified Generation and Retrieval for LLMs
Jintian Zhang | Cheng Peng | Mengshu Sun | Xiang Chen | Lei Liang | Zhiqiang Zhang | Jun Zhou | Huajun Chen | Ningyu Zhang
Findings of the Association for Computational Linguistics: EMNLP 2024
Jintian Zhang | Cheng Peng | Mengshu Sun | Xiang Chen | Lei Liang | Zhiqiang Zhang | Jun Zhou | Huajun Chen | Ningyu Zhang
Findings of the Association for Computational Linguistics: EMNLP 2024
Despite the recent advancements in Large Language Models (LLMs), which have significantly enhanced the generative capabilities for various NLP tasks, LLMs still face limitations in directly handling retrieval tasks. However, many practical applications demand the seamless integration of both retrieval and generation. This paper introduces a novel and efficient One-pass Generation and retrieval framework (OneGen), designed to improve LLMs’ performance on tasks that require both generation and retrieval. The proposed framework bridges the traditionally separate training approaches for generation and retrieval by incorporating retrieval tokens generated autoregressively. This enables a single LLM to handle both tasks simultaneously in a unified forward pass. We conduct experiments on two distinct types of composite tasks, RAG and Entity Linking, to validate the pluggability, effectiveness, and efficiency of OneGen in training and inference. Furthermore, our results show that integrating generation and retrieval within the same context preserves the generative capabilities of LLMs while improving retrieval performance. To the best of our knowledge, OneGen is the first to enable LLMs to conduct vector retrieval during the generation.
IEPile: Unearthing Large Scale Schema-Conditioned Information Extraction Corpus
Honghao Gui | Lin Yuan | Hongbin Ye | Ningyu Zhang | Mengshu Sun | Lei Liang | Huajun Chen
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Honghao Gui | Lin Yuan | Hongbin Ye | Ningyu Zhang | Mengshu Sun | Lei Liang | Huajun Chen
Proceedings of the 62nd Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers)
Large Language Models (LLMs) demonstrate remarkable potential across various domains; however, they exhibit a significant performance gap in Information Extraction (IE). Note that high-quality instruction data is the vital key for enhancing the specific capabilities of LLMs, while current IE datasets tend to be small in scale, fragmented, and lack standardized schema. To this end, we introduce IEPile, a comprehensive bilingual (English and Chinese) IE instruction corpus, which contains approximately 0.32B tokens. We construct IEPile by collecting and cleaning 33 existing IE datasets, and introduce schema-based instruction generation to unearth a large-scale corpus. Experimentally, IEPile enhance the performance of LLMs for IE, with notable improvements in zero-shot generalization. We open-source the resource and pre-trained models, hoping to provide valuable support to the NLP community.
Efficient Knowledge Infusion via KG-LLM Alignment
Zhouyu Jiang | Ling Zhong | Mengshu Sun | Jun Xu | Rui Sun | Hui Cai | Shuhan Luo | Zhiqiang Zhang
Findings of the Association for Computational Linguistics: ACL 2024
Zhouyu Jiang | Ling Zhong | Mengshu Sun | Jun Xu | Rui Sun | Hui Cai | Shuhan Luo | Zhiqiang Zhang
Findings of the Association for Computational Linguistics: ACL 2024
To tackle the problem of domain-specific knowledge scarcity within large language models (LLMs), knowledge graph-retrievalaugmented method has been proven to be an effective and efficient technique for knowledge infusion. However, existing approaches face two primary challenges: knowledge mismatch between public available knowledge graphs and the specific domain of the task at hand, and poor information compliance of LLMs with knowledge graphs. In this paper, we leverage a small set of labeled samples and a large-scale corpus to efficiently construct domain-specific knowledge graphs by an LLM, addressing the issue of knowledge mismatch. Additionally, we propose a three-stage KG-LLM alignment strategy to enhance the LLM’s capability to utilize information from knowledge graphs. We conduct experiments with a limited-sample setting on two biomedical question-answering datasets, and the results demonstrate that our approach outperforms existing baselines.
ChatUIE: Exploring Chat-based Unified Information Extraction Using Large Language Models
Jun Xu | Mengshu Sun | Zhiqiang Zhang | Jun Zhou
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
Jun Xu | Mengshu Sun | Zhiqiang Zhang | Jun Zhou
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
Recent advancements in large language models have shown impressive performance in general chat. However, their domain-specific capabilities, particularly in information extraction, have certain limitations. Extracting structured information from natural language that deviates from known schemas or instructions has proven challenging for previous prompt-based methods. This motivated us to explore domain-specific modeling in chat-based language models as a solution for extracting structured information from natural language. In this paper, we present ChatUIE, an innovative unified information extraction framework built upon ChatGLM. Simultaneously, reinforcement learning is employed to improve and align various tasks that involve confusing and limited samples. Furthermore, we integrate generation constraints to address the issue of generating elements that are not present in the input. Our experimental results demonstrate that ChatUIE can significantly improve the performance of information extraction with a slight decrease in chatting ability.
Zero-Shot Cross-Lingual Document-Level Event Causality Identification with Heterogeneous Graph Contrastive Transfer Learning
Zhitao He | Pengfei Cao | Zhuoran Jin | Yubo Chen | Kang Liu | Zhiqiang Zhang | Mengshu Sun | Jun Zhao
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
Zhitao He | Pengfei Cao | Zhuoran Jin | Yubo Chen | Kang Liu | Zhiqiang Zhang | Mengshu Sun | Jun Zhao
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)
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 paper, we propose a Heterogeneous Graph Interaction Model with Multi-granularity Contrastive Transfer Learning (GIMC) for zero-shot cross-lingual document-level ECI. Specifically, we introduce a heterogeneous graph interaction network to model the long-distance dependencies between events that are scattered over a document. Then, to improve cross-lingual transferability of causal knowledge learned from the source language, we propose a multi-granularity contrastive transfer learning module to align the causal representations across languages. Extensive experiments show our framework outperforms the previous state-of-the-art model by 9.4% and 8.2% of average F1 score on monolingual and multilingual scenarios respectively. Notably, in the multilingual scenario, our zero-shot framework even exceeds GPT-3.5 with few-shot learning by 24.3% in overall performance.
2023
LEGO: A Multi-agent Collaborative Framework with Role-playing and Iterative Feedback for Causality Explanation Generation
Zhitao He | Pengfei Cao | Yubo Chen | Kang Liu | Ruopeng Li | Mengshu Sun | Jun Zhao
Findings of the Association for Computational Linguistics: EMNLP 2023
Zhitao He | Pengfei Cao | Yubo Chen | Kang Liu | Ruopeng Li | Mengshu Sun | Jun Zhao
Findings of the Association for Computational Linguistics: EMNLP 2023
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 large language models since they are often suffering from spurious causal associations when they encounter the content that does not exist in their memory. In this work, we introduce LEGO, a Multi-agent Collaborative Framework with Role-playing and Iterative Feedback for causality explanation generation. Specifically, we treat LLM as character malleable LEGO block and utilize role-playing to assign specific roles to five LLMs. We firstly devise a Fine-grained World Knowledge Integration Module to augment information about tasks for alleviating the phenomenon of spurious causal associations. Then, we leverage an Iterative Feedback and Refinement Module to improve the generated explanation by multi-aspect feedback. Extensive experiments on widely used WIKIWHY and e-CARE datasets show the superiority of our multi-agent framework in terms of reasoning about the causality among cause and effect.
2022
Extracting Trigger-sharing Events via an Event Matrix
Jun Xu | Weidi Xu | Mengshu Sun | Taifeng Wang | Wei Chu
Findings of the Association for Computational Linguistics: EMNLP 2022
Jun Xu | Weidi Xu | Mengshu Sun | Taifeng Wang | Wei Chu
Findings of the Association for Computational Linguistics: EMNLP 2022
A growing interest emerges in event extraction which aims to extract multiple events with triggers and arguments. Previous methods mitigate the problem of multiple events extraction by predicting the arguments conditioned on the event trigger and event type, assuming that these arguments belong to a single event. However, the assumption is invalid in general as there may be multiple events. Therefore, we present a unified framework called MatEE for trigger-sharing events extraction. It resolves the kernel bottleneck by effectively modeling the relations between arguments by an event matrix, where trigger-sharing events are represented by multiple cliques. We verify the proposed method on 3 widely-used benchmark datasets of event extraction. The experimental results show that it beats all the advanced competitors, significantly improving the state-of-the-art performances in event extraction.
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- Lei Liang 7
- Huajun Chen 6
- Zhiqiang Zhang 6
- Jun Xu 4
- Pengfei Cao (鹏飞 曹) 3
- Yubo Chen 3
- Kang Liu 3
- Wen Zhang 3
- Yichi Zhang 3
- Ningyu Zhang 3
- Jun Zhao 3
- Zhuo Chen 2
- Lingbing Guo 2
- Zhitao He 2
- Zhiqiang Liu (刘志强) 2
- Jintian Zhang 2
- Hui Cai 1
- Xiang Chen 1
- Shaokai Chen 1
- Wei Chu 1
- Lun Du 1
- Honghao Gui 1
- Yuxuan Hu 1
- Binbin Hu 1
- Yin Hua 1
- Zhouyu Jiang 1
- Zhuoran Jin 1
- Ruopeng Li 1
- Zhizhen Liu 1
- Shuhan Luo 1
- Sijia Luo 1
- Yujie Luo 1
- Enpei Niu 1
- Cheng Peng 1
- Shuofei Qiao 1
- Jinbo Su 1
- Rui Sun 1
- Ke Wang 1
- Taifeng Wang 1
- Weidi Xu 1
- Yajing Xu 1
- Hongbin Ye 1
- Lin Yuan 1
- Chenlong Zhang 1
- Xiaokang Zhang 1
- Bohan Zhang 1
- Jing Zhang 1
- Wen Zhang 1
- Da Zheng 1
- Ling Zhong 1
- Jun Zhou 1
- Jun Zhou 1
- Yuqi Zhu 1