Zihao Yi
Author directory2026
GRAM: Empowering Agent with Actively Managed Graph-Structured Memory via Reinforcement Learning
Xiangqi Chen | Zihao Yi | Haohao Luo | Ying Shen
Findings of the Association for Computational Linguistics: EMNLP 2026
Xiangqi Chen | Zihao Yi | Haohao Luo | Ying Shen
Findings of the Association for Computational Linguistics: EMNLP 2026
Large Language Model (LLM) agents face a fundamental bottleneck called context flooding in multi-turn information retrieval: as evidence accumulates across interaction turns, their context windows become saturated with redundant, conflicting, and outdated facts. Existing research either compresses interaction history into rolling summaries, sacrificing relational precision, or relies on retrieval-augmented pipelines that lack mechanisms for resolving knowledge conflicts and maintaining a globally consistent belief state. In this work, we introduce GRAM, a reinforcement learning framework designed to train an agent to actively manage and utilize a dynamic graph-structured memory. Rather than passively accumulating retrieved text, the agent learns to incrementally construct and revise a coherent knowledge graph that serves as its persistent belief state, resolving contradictions and preserving logical relationships in memory. Furthermore, We employ Group Relative Policy Optimization to train small language models (under 4B) to master these complex memory-governance behaviors. Experimental results across multiple mainstream question-answering benchmarks demonstrate the superiority of the GRAM framework over existing agentic memory baselines and conventional RAG systems.
Too Good to be Bad: On the Failure of LLMs to Role-Play Villains
Zihao Yi | Qingxuan Jiang | Ruotian Ma | Xingyu Chen | Qu Yang | Mengru Wang | Fanghua Ye | Ying Shen | Zhaopeng Tu | Xiaolong Li | Liefeng Bo
Findings of the Association for Computational Linguistics: ACL 2026
Zihao Yi | Qingxuan Jiang | Ruotian Ma | Xingyu Chen | Qu Yang | Mengru Wang | Fanghua Ye | Ying Shen | Zhaopeng Tu | Xiaolong Li | Liefeng Bo
Findings of the Association for Computational Linguistics: ACL 2026
Large Language Models (LLMs) are increasingly tasked with creative generation, including the simulation of fictional characters. However, their ability to portray non-prosocial, antagonistic personas remains largely unexamined. We hypothesize that the safety alignment of modern LLMs creates a fundamental conflict with the task of authentically role-playing morally ambiguous or villainous characters. To investigate this, we introduce the Moral RolePlay benchmark, a new dataset featuring a four-level moral alignment scale and a balanced test set for rigorous evaluation. We task state-of-the-art LLMs with role-playing characters from moral paragons to pure villains. Our large-scale evaluation reveals a consistent, monotonic decline in role-playing fidelity as character morality decreases. We find that models struggle most with traits directly antithetical to safety principles, such as ”Deceitful” and ”Manipulative”, often substituting nuanced malevolence with superficial aggression. Furthermore, we demonstrate that general chatbot proficiency is a poor predictor of villain role-playing ability, with highly safety-aligned models performing particularly poorly. Our work provides the first systematic evidence of this critical limitation, highlighting a key tension between model safety and creative fidelity. Our benchmark and findings pave the way for developing more nuanced, context-aware alignment methods.
WebSync: A Self-Evolving Web Agent Framework for Co-Evolving Strategic Advice and Executable Skills
Yuanlei Wang | Haohao Luo | Zihao Yi | Ying Shen | Liang Lin
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yuanlei Wang | Haohao Luo | Zihao Yi | Ying Shen | Liang Lin
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
With the advent of large language models, autonomous web agents have achieved more sophisticated capabilities in planning, reflecting, and tool using, enabling automating navigation in complex and dynamic web environments. Despite this, existing efforts to instill experiential learning through memory-centric retrieval or skill-centric synthesis are respectively limited by computational inefficiency and a lack of robustness, preventing web agents from truly self-evolving. To tackle this problem, we introduce a novel web agent framework called WebSync, which is designed to unify strategic advice and skill synthesis through a structured skill recipe to compile experience into executable skills more efficiently and robustly. Furthermore, it enables continuous self-evolving by using runtime feedback to trigger iterative recipe and skill refinement, thus achieving a robust transition from trial-and-error reasoning to proven execution. Experimental results on WebArena and WebVoyager benchmarks demonstrate the superiority and versatility of WebSync across multiple backbone large language models.
From Poetry Parties to Poetry Critics: Benchmarking Classical Chinese Poetry Generation and Evaluation
Zihao Yi | Zhaopeng Tu | Ruotian Ma | Qingxuan Jiang | Zhe Xu | Qingyu Xiao | Yixue Li | Ying Shen | Liefeng Bo
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Zihao Yi | Zhaopeng Tu | Ruotian Ma | Qingxuan Jiang | Zhe Xu | Qingyu Xiao | Yixue Li | Ying Shen | Liefeng Bo
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Classical Chinese poetry generation and evaluation with Large Language Models (LLMs) face two intertwined challenges: existing generation benchmarks rely on simplistic keyword inputs devoid of literary context, and no ground-truth benchmark exists for objectively validating poetry evaluation methods. We present a comprehensive framework addressing both challenges. On the **generation** side, we construct **Honglou-Poem**, the first narrative-driven poetry generation benchmark derived from Dream of the Red Chamber, where each entry provides rich author personas and narrative backgrounds—moving far beyond traditional keyword-to-poem paradigms. A ”Digital Poetry Party” pipeline evaluates 12 state-of-the-art LLMs in this challenging setting. On the **evaluation** side, we introduce **Poetry-Tree**, a benchmark with axiomatically ordered quality levels created through systematic merit degradation, providing objective ground truth for evaluator validation. Leveraging Poetry-Tree as a training signal, we employ **GRPO** reinforcement learning with Spearman’s correlation as the reward to train a dedicated poetry evaluation model, **Poet-4B**. Our Poet-4B achieves a Spearman’s 𝜌 of **0.8253**, dramatically improving from the base model’s 0.2929 and closely approaching the best closed-source model GLM-4.6 (0.8764) with over 100× fewer parameters—a gap of only 0.051 in Spearman’s 𝜌. We release all benchmarks, trained models, and a leaderboard to facilitate future research.
Attention Basin: Why Contextual Position Matters in Large Language Models
Zihao Yi | Zhenqing Ling | Delong Zeng | Haohao Luo | Zhe Xu | Wei Liu | Jian Luan | Wanxia Cao | Ying Shen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Zihao Yi | Zhenqing Ling | Delong Zeng | Haohao Luo | Zhe Xu | Wei Liu | Jian Luan | Wanxia Cao | Ying Shen
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
The performance of Large Language Models (LLMs) is significantly sensitive to the contextual position of information in the input. To investigate the mechanism behind this positional bias, our extensive experiments reveal a consistent phenomenon we term the attention basin: when presented with a sequence of structured items (e.g., retrieved documents or few-shot examples), models systematically assign higher attention to the items at the beginning and end of the sequence, while neglecting those in the middle. Crucially, our analysis further reveals that allocating higher attention to critical information is key to enhancing model performance. Based on these insights, we introduce Attention-Driven Reranking (AttnRank), a two-stage framework that (i) estimates a model’s intrinsic positional attention preferences using a small calibration set, and (ii) reorders retrieved documents or few-shot examples to align the most salient content with these high-attention positions. AttnRank is a model-agnostic, training-free, and plug-and-play method with minimal computational overhead. Experiments on multi-hop QA and few-shot in-context learning tasks demonstrate that AttnRank achieves substantial improvements across 10 large language models of varying architectures and scales, without modifying model parameters or training procedures.