Xiaogang Xu
Author directory2026
UniData: Universal Multimodal Instruction Generation Pipeline
Jiaqi Tang | Yi-Feng Wu | Yuting Zhang | Hao LU | Bowen Fu | Qing-Guo Chen | Xiaogang Xu | Yuwei Hu | Shiyin Lu | Wei Wei | Lei Zhang | Zhao Xu | Weihua Luo | Qifeng Chen | Ying-Cong Chen
Findings of the Association for Computational Linguistics: EMNLP 2026
Jiaqi Tang | Yi-Feng Wu | Yuting Zhang | Hao LU | Bowen Fu | Qing-Guo Chen | Xiaogang Xu | Yuwei Hu | Shiyin Lu | Wei Wei | Lei Zhang | Zhao Xu | Weihua Luo | Qifeng Chen | Ying-Cong Chen
Findings of the Association for Computational Linguistics: EMNLP 2026
Multimodal Large Language Models (MLLMs) are increasingly being applied in a wider range of real-world scenarios. However, due to the substantial labor cost, creating high-quality multimodal instruction datasets for MLLMs remains a significant challenge. Although some methods propose to generate instruction data, they often face limitations in modality support and struggle with generating multi-round instructions. To address these problems, we introduce UniData, a universal instruction generation pipeline, to transform simple user requirements into multi-round, multimodal instructions. Specifically, UniData first expands user requirements into multiple diverse events. Using these events, UniData then integrates an any-to-any large model for multimodal instruction generation. Finally, UniData enhances data quality by correcting irrelevant and redundant inference flow, leveraging correlations between instruction rounds. To train this pipeline, we also build UniDataset, a dataset comprising 20,000 entries across nine modalities for improved multimodal generation. Our experiments demonstrate that UniData achieves SOTA performance in data quality and can also enhance the understanding and generation capabilities of other multimodal models.
LPO: Towards Accurate GUI Agent Interaction via Location Preference Optimization
Jiaqi Tang | Yu Xia | Yi-Feng Wu | Yuwei Hu | Chen Yuhui | Qing-Guo Chen | Xiaogang Xu | Xiangyu Wu | Hao LU | Yanqing Ma | Shiyin Lu | Qifeng Chen
Findings of the Association for Computational Linguistics: ACL 2026
Jiaqi Tang | Yu Xia | Yi-Feng Wu | Yuwei Hu | Chen Yuhui | Qing-Guo Chen | Xiaogang Xu | Xiangyu Wu | Hao LU | Yanqing Ma | Shiyin Lu | Qifeng Chen
Findings of the Association for Computational Linguistics: ACL 2026
The advent of autonomous agents is transforming interactions with Graphical User Interfaces (GUIs) by employing natural language as a powerful intermediary. Despite the predominance of supervised fine-tuning (SFT) methods in current GUI agents for achieving spatial localization, these methods face substantial challenges due to their limited capacity to accurately perceive positional data. Existing strategies, such as reinforcement learning, often fail to assess positional accuracy effectively, thereby restricting their utility. In response, we introduce Location Preference Optimization (LPO), a novel approach that leverages locational data to optimize interaction preferences. LPO uses information entropy to predict interaction positions by focusing on zones rich in information. Besides, we further introduce a dynamic location reward function based on physical distance, reflecting the varying importance of interaction positions. Supported by Group Relative Preference Optimization (GRPO), LPO facilitates an extensive exploration of GUI environments and significantly enhances interaction precision. Comprehensive experiments demonstrate LPO’s superior performance, achieving SOTA results across both offline benchmarks and real-world online evaluations.
PerMemSafe: Benchmarking Implicit Personalized Safety of Long Horizon Self-Evolving Agents
Hengyu An | Minxi Li | Naen Xu | Chunyi Zhou | Xiaogang Xu | Tianyu Du | Jinbao Li | Shouling Ji
Findings of the Association for Computational Linguistics: ACL 2026
Hengyu An | Minxi Li | Naen Xu | Chunyi Zhou | Xiaogang Xu | Tianyu Du | Jinbao Li | Shouling Ji
Findings of the Association for Computational Linguistics: ACL 2026
Self-evolving agents achieve personalization by accumulating user-specific memories over long horizons. This capability, however, introduces novel safety risks, as responses that are generally safe may become harmful in user-specific contexts. Such safety-relevant contexts often emerge implicitly and evolve over time during long-horizon conversations, rendering traditional context-independent safety evaluations insufficient. To address this, we formally define Implicit Personalized Safety and present PerMemSafe, the first benchmark for evaluating implicit personalized safety of self-evolving agents in long-horizon interactions. Empirical results reveal significant limitations of existing self-evolving agents, with even the strongest achieving only around 50% safety rate, highlighting systematic failures in reasoning about personalized safety risks. To mitigate this, we propose SentinelMem, an active risk-aware memory framework that explicitly models personalized risk inference and memory evolution. Experiments show that SentinelMem improves implicit personalized safety by 23.8% over prior memory frameworks while maintaining helpfulness in long-horizon interactions.
LEAP: Likelihood Elicitation and Aggregation for LLM-based Probabilistic Forecasting
Yufei Chen | Yiran Zhao | Xiaogang Xu | Qipeng Xie | Jiafei Wu | Zhe Liu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yufei Chen | Yiran Zhao | Xiaogang Xu | Qipeng Xie | Jiafei Wu | Zhe Liu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
LLM-based forecasting systems have improved on real-world tasks like financial markets and sports outcomes, largely by strengthening search, but the final prediction step remains crude: systems typically ask an LLM to read all collected evidence and emit one answer. We call this approach Monolithic Prediction, which fits forecasting poorly: probabilities over competing outcomes carry information valuable for downstream decisions, but a holistic answer collapses the supporting evidence, discarding this information. To address the above issue, we propose LEAP Likelihood Elicitation and Aggregation for Probabilistic forecasting) to keep the LLM out of the final prediction. LEAP treats evidence items as local signals, uses likelihood parameters to estimate how each supports candidate outcomes, and aggregates them through a deterministic probabilistic model into a posterior over candidate outcomes, thereby preserving per-item contributions, yielding comprehensive forecasts, and simplifying audits. We build a benchmark covering real-world prediction, information-seeking, and browsing tasks, evaluating LEAP on our custom agent loop and practical agent CLI frameworks. Given the same evidence, LEAP outperforms Monolithic Prediction in most settings and metrics across models.
Last But Not Least: Boundary Attention CalibratiON for Multimodal KV Cache Compression
Tianhao Chen | Yuheng Wu | Kelu Yao | Xiaogang Xu | Xiaobin Hu | Dongman Lee
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Tianhao Chen | Yuheng Wu | Kelu Yao | Xiaogang Xu | Xiaobin Hu | Dongman Lee
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Multimodal Large Language Models (MLLMs) achieve strong vision-language reasoning but incur large KV caches and high decoding latency with long visual contexts. Existing compression methods rely on observation window attention for stable token importance estimation, yet this aggregation can dilute sparse critical evidence and discard answer-relevant tokens under aggressive compression. We identify last query attention as a complementary signal for recovering such evidence, though its irrelevant signals may introduce additional noise. We propose BACON, a plug-and-play method that calibrates observation window attention with last query evidence while suppressing noise through intra-layer coherence and inter-layer persistence. Across diverse benchmarks, models, budgets, and compression methods, BACON improves multimodal KV-cache compression by 7.5% on average under the most aggressive budget, with gains up to 30.9%.
Streaming Communication in Multi-Agent Reasoning
Zhen Yang | Xiaogang Xu | Wen Wang | Cong Chen | Xander Xu | Ying-Cong Chen
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Zhen Yang | Xiaogang Xu | Wen Wang | Cong Chen | Xander Xu | Ying-Cong Chen
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Multi-agent reasoning systems adopt a generate-then-transfer paradigm that forces end-to-end latency to scale linearly with pipeline depth. We introduce StreamMA, a multi-agent reasoning system that streams each reasoning step to downstream agents as soon as it is generated, pipelining adjacent agents and thus reducing latency. Surprisingly, this pipelining also improves effectiveness: because multi-step reasoning quality is non-uniform and early steps are more reliable than later ones, working with these reliable early steps instead of the full chain prevents error-prone late steps from misleading downstream agents. We formalize both advantages with the first closed-form joint analysis of stream, serial, and single protocols, deriving the effectiveness ordering, speedup upper bound, and cost ratio. Across eight reasoning benchmarks spanning mathematics, science, and code, three frontier LLMs (Claude Opus 4.6, GPT-5.4, and GLM-5.2), and three topologies (Chain, Tree, Graph), StreamMA outperforms both baselines (avg.+7.3pp, max +22.4pp on HMMT2026; Claude Opus 4.6-High). Beyond these contributions, we discover a step-level scaling law: increasing per-agent steps consistently improves both effectiveness and efficiency, a new scaling dimension orthogonal to and composable with agent-count scaling.
Beyond Outcome Gaps: Process-Aware Fairness Diagnosis for LLM-based Multi-Agent Decision Systems
Yiran Zhao | Lu Zhou | Liming Fang | Yufei Chen | Jiafei Wu | Zhe Liu | Xiaogang Xu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yiran Zhao | Lu Zhou | Liming Fang | Yufei Chen | Jiafei Wu | Zhe Liu | Xiaogang Xu
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
LLM-based multi-agent systems (MAS) are increasingly considered for high-stakes decision-making, yet outcome-based fairness audits can miss where risks arise within the decision trajectory. We present SCOPED-Hiring, a process-aware fairness diagnosis pipeline for LLM-based hiring MAS. SCOPED-Hiring constructs controlled resume variants, runs role-based hiring committees, logs over 311K structured decision trajectories, and converts trajectory fields into quantitative fairness signals organized by six diagnostic lenses: final outcome, counterfactual, process, pathway, dynamic, and design effects. SCOPED-Hiring reveals that balanced final hire rates can mask hidden trajectory unfairness in multi-agent decision trajectories: career gaps trigger suspicion, proxy cues shape qualification judgments, and identity cues lead to unequal investigation. Targeted repair guided by these diagnoses reduces total layered burden by 72.3% while shifting the hire rate by only 1.86 pp, showing that process diagnosis can guide effective repair.
ACIArena: Toward Unified Evaluation for Agent Cascading Injection
Hengyu An | Minxi Li | Jinghuai Zhang | Naen Xu | Chunyi Zhou | Changjiang Li | Xiaogang Xu | Tianyu Du | Shouling Ji
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Hengyu An | Minxi Li | Jinghuai Zhang | Naen Xu | Chunyi Zhou | Changjiang Li | Xiaogang Xu | Tianyu Du | Shouling Ji
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Collaboration and information sharing empower Multi-Agent Systems (MAS) but also introduce a critical security risk known as Agent Cascading Injection (ACI). In such attacks, a compromised agent exploits inter-agent trust to propagate malicious instructions, causing cascading failures across the system. However, existing studies consider only limited attack strategies and simplified MAS settings, limiting their generalizability and comprehensive evaluation. To bridge this gap, we introduce ACIArena, a unified framework for evaluating the robustness of MAS. ACIArena offers systematic evaluation suites spanning multiple attack surfaces (i.e., external inputs, agent profiles, inter-agent messages) and attack objectives (i.e., instruction hijacking, task disruption, information exfiltration). Specifically, ACIArena establishes a unified specification that jointly supports MAS construction and attack–defense modules. It covers six widely used MAS implementations and provides a benchmark of 1,356 test cases for systematically evaluating MAS robustness. Our benchmarking results show that evaluating MAS robustness solely through topology is insufficient; robust MAS require deliberate role design and controlled interaction patterns. Moreover, defenses developed in simplified environments often fail to transfer to real-world settings; narrowly scoped defenses may even introduce new vulnerabilities. ACIArena aims to provide a solid foundation for advancing deeper exploration of MAS design principles.
2024
HELPD: Mitigating Hallucination of LVLMs by Hierarchical Feedback Learning with Vision-enhanced Penalty Decoding
Fan Yuan | Chi Qin | Xiaogang Xu | Piji Li
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Fan Yuan | Chi Qin | Xiaogang Xu | Piji Li
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Large Vision-Language Models (LVLMs) have shown remarkable performance on many visual-language tasks. However, these models still suffer from multimodal hallucination, which means the generation of objects or content that violates the images. Many existing work detects hallucination by directly judging whether an object exists in an image, overlooking the association between the object and semantics. To address this issue, we propose Hierarchical Feedback Learning with Vision-enhanced Penalty Decoding (HELPD). This framework incorporates hallucination feedback at both object and sentence semantic levels. Remarkably, even with a marginal degree of training, this approach can alleviate over 15% of hallucination. Simultaneously, HELPD penalizes the output logits according to the image attention window to avoid being overly affected by generated text. HELPD can be seamlessly integrated with any LVLMs. Our experiments demonstrate that the proposed framework yields favorable results across multiple hallucination benchmarks. It effectively mitigates hallucination for different LVLMs and concurrently improves their text generation quality.
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Co-authors
- Hengyu An 2
- Qifeng Chen 2
- Qing-Guo Chen 2
- Ying-Cong Chen 2
- Yufei Chen 2
- Tianyu Du 2
- Yuwei Hu 2
- Shouling Ji 2
- Hao LU 2
- Minxi Li 2
- Zhe Liu 2
- Shiyin Lu 2
- Jiaqi Tang 2
- Jiafei Wu 2
- Yi-Feng Wu 2
- Naen Xu 2
- Yiran Zhao 2
- Chunyi Zhou 2
- Cong Chen (陈聪) 1
- Tianhao Chen 1
- Liming Fang 1
- Bowen Fu 1
- Xiaobin Hu 1
- Dongman Lee 1
- Changjiang Li 1
- Jinbao Li 1
- Piji Li (李丕绩) 1
- Weihua Luo 1
- Yanqing Ma 1
- Chi Qin 1
- Wen Wang 1
- Wei Wei 1
- Xiangyu Wu 1
- Yuheng Wu 1
- Yu Xia 1
- Qipeng Xie 1
- Xander Xu 1
- Zhao Xu 1
- Zhen Yang 1
- Kelu Yao 1
- Fan Yuan (袁凡) 1
- Chen Yuhui 1
- Jinghuai Zhang 1
- Lei Zhang 1
- Yuting Zhang 1
- Lu Zhou 1