Haifeng Chen
Other people with similar names: Haifeng Chen
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2026
LOKA: Conflict-Aware LLM Knowledge Update with Adaptive Knowledge Memory
Binchi Zhang | Zhengzhang Chen | Zaiyi Zheng | Jundong Li | Haifeng Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Binchi Zhang | Zhengzhang Chen | Zaiyi Zheng | Jundong Li | Haifeng Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large Language Models (LLMs) have achieved remarkable success in natural language processing by encoding extensive knowledge, but their utility relies on timely updates as human knowledge keeps evolving. In this paper, we investigate the problem of LLM knowledge updates, which requires simultaneously unlearning unwanted information and learning new knowledge. Existing approaches that tackle unlearning and learning separately encounter *task conflicts* and *knowledge management issues* when applied to comprehensive knowledge updates.In this paper, we validate our findings with theoretical analysis and empirical evidence, and propose LOKA, a conflict-aware framework for Large language mOdel Knowledge updAtes. During training, LOKA introduces an adaptive knowledge memory approach in which updated knowledge is allocated across multiple memory units. During inference, LOKA retrieves the most relevant memory unit from the knowledge memory and integrates it with the original LLM to apply updated knowledge, while a learning-based router controls the activation of the knowledge memory to improve knowledge utilization. Extensive experiments demonstrate the efficacy of LOKA in achieving accurate, flexible, and conflict-aware knowledge updates.
Mind the Gap in Cultural Alignment: Task-Aware Culture Management for Large Language Models
Binchi Zhang | Xujiang Zhao | Jundong Li | Haifeng Chen | Zhengzhang Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Binchi Zhang | Xujiang Zhao | Jundong Li | Haifeng Chen | Zhengzhang Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) are increasingly deployed in culturally sensitive real-world tasks. However, existing cultural alignment approaches fail to align LLMs’ broad cultural values with the specific goals of downstream tasks and suffer from cross-culture interference. We propose CultureManager, a novel pipeline for task-specific cultural alignment. CultureManager synthesizes task-aware cultural data in line with target task formats, grounded in culturally relevant web search results. To prevent conflicts between cultural norms, it manages multi-culture knowledge learned in separate adapters with a culture router that selects the appropriate one to apply. Experiments across five national cultures and ten culture-sensitive tasks show consistent improvements over prompt-based and fine-tuning baselines. Our results demonstrate the necessity of task adaptation and modular culture management for effective cultural alignment.
Representation Interventions Enable Lifelong Knowledge Memory Control in LLMs
Xuyuan Liu | Shengyu Chen | Xinshuai Dong | Yanchi Liu | Xujiang Zhao | Haoyu Wang | Yujun Yan | Haifeng Chen | Zhengzhang Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Xuyuan Liu | Shengyu Chen | Xinshuai Dong | Yanchi Liu | Xujiang Zhao | Haoyu Wang | Yujun Yan | Haifeng Chen | Zhengzhang Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Large language models (LLMs) often produce incorrect or outdated content. Updating their knowledge efficiently and accurately without costly retraining is a major challenge. This problem is particularly challenging for complex, unstructured knowledge in lifelong settings, where many edits must coexist without interference. We introduce **RILKE** (**R**epresentation **I**ntervention for **L**ifelong **K**nowledg**E** Control), a robust and scalable method that treats knowledge control as interventions within the model’s representation space. Leveraging representation-space expressiveness, we identify two key properties enabling RILKE to achieve fine-grained control over complex, unstructured knowledge while maintaining general utility with frozen base weights. During training, RILKE learns paraphrase-robust and edit-localized modules that limit each update to a low-dimensional subspace to minimize cross-edit interference. In inference, a query-adaptive router selects the appropriate module to guide the model’s generation. Across LLaMA and Qwen models, RILKE scales effectively to large-scale benchmarks, demonstrating high edit success and strong paraphrase generalization while preserving general utility with modest memory overhead. These results show RILKE is an effective and scalable solution for lifelong knowledge control in LLMs.
Stop When Enough: Adaptive Early-Stopping for Chain-of-Thought Reasoning
Renliang Sun | Wei Cheng | Dawei Li | Haifeng Chen | Wei Wang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Renliang Sun | Wei Cheng | Dawei Li | Haifeng Chen | Wei Wang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Chain-of-Thought (CoT) reasoning has driven recent gains of large language models (LLMs) on reasoning-intensive tasks by externalizing intermediate steps. However, excessive or redundant reasoning — so-called overthinking — can increase inference costs and lead LLMs toward incorrect conclusions. In this paper, we present REFRAIN ( ̲REFlective- ̲Redundancy for ̲Adaptive ̲INference), a training-free framework that adaptively determines when to stop reasoning to mitigate overthinking. REFRAIN integrates a two-stage stop discriminator to identify reflective yet redundant reasoning and a sliding-window Upper Confidence Bound (SW-UCB) multi-armed bandit controller to dynamically adjust stopping thresholds according to problem difficulty without supervision or fine-tuning. Across four representative benchmarks and two model families, REFRAIN reduces token usage by 20-55% while maintaining or improving accuracy compared to standard CoT prompting. Extensive ablation and robustness analyses demonstrate its stability across models, scorers, and prompt variations. In summary, our findings highlight when-to-stop as a new and practical axis of test-time scaling — enabling models to reason not just more, but just enough.
Multi-Agent Procedural Graph Extraction with Structural and Logical Refinement
Wangyang Ying | Yanchi Liu | Xujiang Zhao | Wei Cheng | Zhengzhang Chen | Wenchao Yu | Yanjie Fu | Haifeng Chen
Findings of the Association for Computational Linguistics: EACL 2026
Wangyang Ying | Yanchi Liu | Xujiang Zhao | Wei Cheng | Zhengzhang Chen | Wenchao Yu | Yanjie Fu | Haifeng Chen
Findings of the Association for Computational Linguistics: EACL 2026
Automatically extracting workflows as procedural graphs from natural language is a promising yet underexplored task that requires ensuring both structural validity and logical alignment. Recent advances in large language models (LLMs) show potential for graph extraction, but often yield ill-formed structures or misinterpret logical constructs such as gateways. We introduce , a multi-agent framework that treats procedural graph extraction as a multi-round reasoning process with structural and logical refinement agents. The framework operates in three iterative stages: (1) an LLM-based graph extraction phase, (2) a structural feedback phase where a simulation agent diagnoses and explains structural issues, and (3) a logical feedback phase where a semantic agent aligns semantics between flow logic and linguistic cues in the source text. Important feedback is prioritized and expressed in natural language, which is injected into the next-round prompt, enabling interpretable and controllable refinement. This modular design allows agents to target distinct error types without supervision or parameter updates. Experiments demonstrate that achieves substantial improvements in both structural correctness and logical consistency over strong baselines.
Uncertainty-Aware Test-Time Search for Optimization Problem Solving
Linlin Yu | Xujiang Zhao | Dong Li | Yanchi Liu | Wei Cheng | Zhengzhang Chen | Chen Zhao | Feng Chen | Haifeng Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Linlin Yu | Xujiang Zhao | Dong Li | Yanchi Liu | Wei Cheng | Zhengzhang Chen | Chen Zhao | Feng Chen | Haifeng Chen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Automatically solving optimization problems from natural language descriptions with both efficiency and reliability is highly desirable but remains challenging. Language model hallucinations and the limited availability of labeled datasets often result in misaligned formulations, code errors, and feasibility failures We propose UMCTS, an Uncertainty-aware Monte Carlo Tree Search framework that combines the language understanding capability of large language models with the reliability of well-established solvers. UMCTS structures the solution process into four stages: global instruction, assumptions, mathematical formulation, and solver code generation. It employs Monte Carlo Tree Search with semantic-equivalence pruning, prior-guided exploration, and solver-based feasibility checks. An LLM judge provides numerical reward signals, qualitative error information, and uncertainty estimates. These signals are backpropagated to guide the search and flag unreliable outputs. Across six public benchmarks, UMCTS achieves state-of-the-art solution accuracy, improves efficiency by reducing token usage.
Decoding Time Series with LLMs: A Multi-Agent Framework for Cross-Domain Annotation
Minhua Lin | Zhengzhang Chen | Yanchi Liu | Xujiang Zhao | Zongyu Wu | Junxiang Wang | Xiang Zhang | Suhang Wang | Haifeng Chen
Findings of the Association for Computational Linguistics: EACL 2026
Minhua Lin | Zhengzhang Chen | Yanchi Liu | Xujiang Zhao | Zongyu Wu | Junxiang Wang | Xiang Zhang | Suhang Wang | Haifeng Chen
Findings of the Association for Computational Linguistics: EACL 2026
Time series data is ubiquitous across various domains, including manufacturing, finance, and healthcare. High-quality annotations are essential for effectively understanding time series and facilitating downstream tasks. However, obtaining such annotations is challenging, particularly in mission-critical domains. In this paper, we propose TESSA, a multi-agent system designed to automatically generate both general and domain-specific annotations for time series data. TESSA introduces two agents: a general annotation agent and a domain-specific annotation agent. The general agent captures common patterns and knowledge across multiple source domains, leveraging both time-series-wise and text-wise features to generate general annotations. Meanwhile, the domain-specific agent utilizes limited annotations from the target domain to learn domain-specific terminology and generate targeted annotations. Extensive experiments on multiple synthetic and real-world datasets demonstrate that TESSA effectively generates high-quality annotations, outperforming existing methods.
DeepSieve: Information Sieving via LLM-as-a-Knowledge-Router
Minghao Guo | Qingcheng Zeng | Xujiang Zhao | Yanchi Liu | Wenchao Yu | Mengnan Du | Haifeng Chen | Wei Cheng
Findings of the Association for Computational Linguistics: EACL 2026
Minghao Guo | Qingcheng Zeng | Xujiang Zhao | Yanchi Liu | Wenchao Yu | Mengnan Du | Haifeng Chen | Wei Cheng
Findings of the Association for Computational Linguistics: EACL 2026
Large Language Models (LLMs) excel at many reasoning tasks but struggle with knowledge-intensive queries due to their inability to dynamically access up-to-date or domain-specific information. Retrieval-Augmented Generation (RAG) has emerged as a promising solution, enabling LLMs to ground their responses in external sources. However, existing RAG methods lack fine-grained control over both the query and source sides, often resulting in noisy retrieval and shallow reasoning. In this work, we introduce DeepSieve, an agentic RAG framework that incorporates information sieving via LLM-as-a-knowledge-router. DeepSieve decomposes complex queries into structured sub-questions and recursively routes each to the most suitable knowledge source, filtering irrelevant information through a multi-stage distillation process. Our design emphasizes modularity, transparency, and adaptability, leveraging recent advances in agentic system design. Experiments on multi-hop QA tasks across heterogeneous sources demonstrate improved reasoning depth, retrieval precision, and interpretability over conventional RAG approaches.
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Co-authors
- Zhengzhang Chen 6
- Xujiang Zhao 6
- Yanchi Liu 5
- Wei Cheng 4
- Jundong Li 2
- Wenchao Yu 2
- Binchi Zhang 2
- Shengyu Chen 1
- Feng Chen 1
- Xinshuai Dong 1
- Mengnan Du 1
- Yanjie Fu 1
- Minghao Guo 1
- Dawei Li 1
- Dong Li 1
- Minhua Lin 1
- Xuyuan Liu 1
- Renliang Sun 1
- Haoyu Wang 1
- Wei Wang 1
- Junxiang Wang 1
- Suhang Wang 1
- Zongyu Wu 1
- Yujun Yan 1
- Wangyang Ying 1
- Linlin Yu 1
- Qingcheng Zeng 1
- Xiang Zhang 1
- Chen Zhao 1
- Zaiyi Zheng 1