Yihe Liu
2026
G-LoRA: Global-Local Decoupled Low-Rank Adaptation
Jiahao Xiong | Yihong Huang | Yihe Liu | Xianming Hu | Hongbo Zhao | Kai Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Jiahao Xiong | Yihong Huang | Yihe Liu | Xianming Hu | Hongbo Zhao | Kai Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Low-Rank Adaptation (LoRA) has achieved remarkable progress in improving the fine-tuning efficiency and downstream performance of large language models (LLMs). Although prior work has recognized that different weight update matrices 𝛥 𝐖 exhibit varying importance and therefore should be allocated different ranks, parameters within the same update matrix are still typically constrained to a uniform rank configuration, neglecting fine-grained parameter-level heterogeneity. To address this limitation, we propose G-LoRA (Global-Local Decoupled LoRA), which decomposes each update matrix into global and local adapters. The key idea is to reorganize the rows and columns of the update matrix using a first-order Taylor approximation of parameter importance, such that highly influential parameters are clustered into a local sub-block of 𝛥 𝐖. During training, the local adapter then focuses on this high-importance sub-region and is allocated a higher rank, whereas the global adapter captures the residual updates for the entire update matrix with relatively lower rank. By allocating higher representational capacity to more critical parameters, G-LoRA enables more efficient utilization of model resources. Extensive evaluations on benchmarks spanning commonsense reasoning, mathematical reasoning, and code generation demonstrate that G-LoRA achieves up to 2.7% absolute accuracy improvement over LoRA and its variants, validating its effectiveness for LLM fine-tuning.
ZoomRAG: Hierarchical Random-walk Zooming across Multi-scale Information Graphs for Fast and Accurate RAG
Xianming Hu | Jingyang Chen | Bin Tang | Yihe Liu | Yihong Huang | Hongbo Zhao | Nuoyi Chen | Jie Zhang | Ping Li | Kai Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Xianming Hu | Jingyang Chen | Bin Tang | Yihe Liu | Yihong Huang | Hongbo Zhao | Nuoyi Chen | Jie Zhang | Ping Li | Kai Zhang
Findings of the Association for Computational Linguistics: ACL 2026
Retrieval-Augmented Generation is a powerful tool for NLP applications. Yet, it is challenging to encode large knowledge bases as compact offline structures while simultaneously achieving accurate, low-latency online retrieval. We propose **ZoomRAG**, a coarse-to-fine, hierarchical graph inference method to tackle the challenges. ZoomRAG formulates the retrieval task as random walks across multi-scale relational graphs. *At the coarse level*, it constructs a global relational graph and performs a query-initiated random walk to quickly locate a few relevant documents over the entire corpus. *At the finer level*, it “zooms into” the selected documents to capture fine-grained semantic and temporal relations, and conducts a second random walk to pinpoint salient evidence chunks for generation. This coarse-to-fine strategy substantially reduces offline indexing costs and accelerates online retrieval. Moreover, random-walk based topological reasoning over rich, multi-scale relational structures enables ZoomRAG to effectively aggregate multi-hop evidence while suppressing noise. Finally, we address the difficulty of handling concurrent RAG queries by **algorithm-parallel ZoomRAG**. Overall, ZoomRAG avoids building expensive knowledge graphs while achieving 2.2% – 4.9% absolute gains in accuracy over SOTA RAG models, with an average online retrieval latency per-query as low as 0.019 secs by processing hundreds of queries concurrently.
Localized Low-Rank Adaptation within Clustered Parameter Subspaces
Jiahao Xiong | Yihe Liu | Xianming Hu | Hongbo Zhao | Nuoyi Chen | Jie Zhang | Kai Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Jiahao Xiong | Yihe Liu | Xianming Hu | Hongbo Zhao | Nuoyi Chen | Jie Zhang | Kai Zhang
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Low-Rank Adaptation (LoRA) for large language models (LLMs) has achieved significant success in various domains. So far, most algorithms in the LoRA-family rely on global low-rank factors spanning the entire update weight matrix (𝛥 𝐖). Through careful analysis, however, we observe that the 𝛥 𝐖 during fine-tuning typically exhibit heterogeneous subspace clusters, each corresponding to specific sub-sets of rows and columns. This structural heterogeneity suggests that global low-rank factors may not optimally capture the local variations needed for effective model adaptation. To address this limitation, we propose LoRA within Clustered Parameter Subspaces, or CPS-LoRA, which performs independent low-rank updates within clustered blocks of parameter matrices. The key idea is to group the rows/columns of the update matrix into locally coherent, and maximally uncorrelated subspaces, perform low-rank adaptations in each subspace, and iteratively update the partition and local adaptations. This allows adapting to local structures more precisely while preserving high efficiency. Theoretical analysis reveals that in case 𝛥 𝐖 can be partitioned into subspace blocks with non-overlapping basis, CPS-LoRA have superior parameter efficiency than global adaptations. Empirical evaluations further demonstrate better rank utilization of CPS-LoRA and its consistent improvements against LoRA (and variants) by up to 3.0% in absolute accuracy in various benchmarks.
Experience-Driven Multi-Agent Optimization for Black-Box Jailbreak Attacks on Large Language Models
Zhaoyang Han | Yihe Liu | Kai Zhang | Ping Li
Findings of the Association for Computational Linguistics: ACL 2026
Zhaoyang Han | Yihe Liu | Kai Zhang | Ping Li
Findings of the Association for Computational Linguistics: ACL 2026
The rapid discovery of jailbreak prompts has revealed the alarming fragility of safety alignment in frontier large language models (LLMs). While jailbreak techniques play a critical role in red-teaming and safety evaluation, existing methods exhibit three key limitations: (i) poor transferability across model families, requiring model-specific manual tuning; (ii) heavy reliance on large-scale prompt enumeration or exhaustive search, causing prohibitive query costs and poor scalability; and (iii) high sensitivity to input preprocessing or refusal-oriented fine-tuning, leading to attack failures once the underlying model is updated. To address these, we propose Experience-driven Multi-agent Jailbreak Optimization (EMJO), which couples three collaborating agents (Attacker, Analyzer, and Judge) into a closed-loop “probe–evaluate–revise” process, together with a dynamic experience bank accumulating high-quality successful prompts and reusable strategy patterns across iterations and tasks. This design enables query-efficient and transferable jailbreak optimization under black-box access. Extensive experiments on diverse LLMs demonstrate that EMJO consistently outperforms existing black-box jailbreak baselines, achieving up to 11% absolute improvement in attack success rate while reducing the average query cost by up to 7.9× across two benchmark datasets. These results indicate that EMJO offers an effective and scalable paradigm for systematic jailbreak discovery.
2022
M-SENA: An Integrated Platform for Multimodal Sentiment Analysis
Huisheng Mao | Ziqi Yuan | Hua Xu | Wenmeng Yu | Yihe Liu | Kai Gao
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics: System Demonstrations
Huisheng Mao | Ziqi Yuan | Hua Xu | Wenmeng Yu | Yihe Liu | Kai Gao
Proceedings of the 60th Annual Meeting of the Association for Computational Linguistics: System Demonstrations
M-SENA is an open-sourced platform for Multimodal Sentiment Analysis. It aims to facilitate advanced research by providing flexible toolkits, reliable benchmarks, and intuitive demonstrations. The platform features a fully modular video sentiment analysis framework consisting of data management, feature extraction, model training, and result analysis modules. In this paper, we first illustrate the overall architecture of the M-SENA platform and then introduce features of the core modules. Reliable baseline results of different modality features and MSA benchmarks are also reported. Moreover, we use model evaluation and analysis tools provided by M-SENA to present intermediate representation visualization, on-the-fly instance test, and generalization ability test results. The source code of the platform is publicly available at https://github.com/thuiar/M-SENA.