Ziyu Shen
Author directory2026
Unveiling the Deficiencies of Pre-trained Text-and-Layout Models in Real-world Visually-rich Document Information Extraction
Chong Zhang | Yixi Zhao | Yulu Xie | Chenshu Yuan | Yi Tu | Ya Guo | Mingxu Chai | Ziyu Shen | Yue Zhang | Qi Zhang
Findings of the Association for Computational Linguistics: EACL 2026
Chong Zhang | Yixi Zhao | Yulu Xie | Chenshu Yuan | Yi Tu | Ya Guo | Mingxu Chai | Ziyu Shen | Yue Zhang | Qi Zhang
Findings of the Association for Computational Linguistics: EACL 2026
Recently developed pre-trained text-and-layout models (PTLMs) have shown remarkable success in multiple information extraction tasks on visually-rich documents (VrDs). However, despite achieving extremely high performance on benchmarks, their real-world performance falls short of expectations. Owing to this issue, we investigate the prevailing evaluation pipeline to reveal that: (1) The inadequate annotations within benchmark datasets introduce spurious correlations between task inputs and labels, which would lead to overly-optimistic estimation of model performance. (2) The evaluation solely relies on the performance on benchmarks and is insufficient to comprehensively explore the capabilities of methods in real-world scenarios. These problems impede the prevailing evaluation pipeline from reflecting the real-world performance of methods, misleading the design choices of method optimization. In this work, we introduce EC-FUNSD, an entity-centric dataset crafted for benchmarking information extraction from visually-rich documents. This dataset contains diverse layouts and high-quality annotations. Additionally, this dataset disentangles the falsely-coupled segment and entity annotations that arises from the block-level annotation of FUNSD. Using the proposed dataset, we evaluate the real-world information extraction capabilities of PTLMs from multiple aspects, including their absolute performance, as well as generalization, robustness and fairness. The results indicate that prevalent PTLMs do not perform as well as anticipated in real-world information extraction scenarios. We hope that our study can inspire reflection on the directions of PTLM development.
Prefix-Adaptive Block Diffusion for Efficient Document Recognition
Mingxu Chai | Ziyu Shen | Chenyu Liu | Jihua Kang | Tao Gui | Qi Zhang
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Mingxu Chai | Ziyu Shen | Chenyu Liu | Jihua Kang | Tao Gui | Qi Zhang
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Block Diffusion Models (BDMs) support parallel generation, flexible-length output, and KV caching, making them promising for efficient document parsing. However, existing BDMs bind denoising and cache commitment to fixed block boundaries: parallelism shrinks during intra-block denoising, while generated tokens cannot be cached until the whole block is completed. Moreover, intra-block bidirectional denoising conflicts with inter-block autoregression, creating inconsistent information flow that can challenge structure-sensitive recognition. We propose the Prefix-Adaptive Block Diffusion Model (PA-BDM), which replaces intra-block bidirectional denoising with causal denoising from prefix to suffix and treats the block size as a maximum candidate range rather than a fixed commitment unit. PA-BDM uses Confidence-gated Structural Loss (CSL) to build low-entropy prefixes before extending training to longer continuations. During inference, Progressive Prefix Commitment (PPC) then dynamically commits the longest reliable prefix into the KV cache and resets the next candidate range from the updated prefix, restoring a large parallel decoding space at each step. Experiments show that the 3B PA-BDM achieves higher recognition scores on several benchmarks and improves inference throughput by 71.6% over the 2.5B MinerU-Diffusion.
State-Conditioned Visual Evidence Retrieval for Fine-Grained Perception in Document Vision-Language Models
Mingxu Chai | Chenyu Liu | Ziyu Shen | Jiazheng Zhang | Kaidi Zhang | Jihua Kang | Tao Gui | Qi Zhang
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Mingxu Chai | Chenyu Liu | Ziyu Shen | Jiazheng Zhang | Kaidi Zhang | Jihua Kang | Tao Gui | Qi Zhang
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Compared with typical vision–language tasks, document parsing places stronger demands on fine-grained visual perception. Existing vision–language model (VLM)–based parsing approaches rely on globally compressed visual tokens, where fine-grained details are entangled within a single representation and repeatedly accessed during decoding. However, we observe that the visual evidence for each prediction is typically localized and conditioned on the current decoding state, whereas such representations must be accessed in full at every decoding step, resulting in inefficient computation. To address this mismatch, we formulate perception as state-conditioned visual evidence retrieval (SCVER) during autoregressive decoding. The model operates on a compact global representation for coarse structure and retrieves a small set of relevant high-resolution regions conditioned on the current token state. This coarse-to-fine design enables on-demand access to fine-grained visual cues, relieving globally shared representations from encoding all fine-grained details. We further find that learning such state-conditioned retrieval in VLMs is challenging and unstable. To stabilize this process, we introduce a Spatially-Guided Learning Objective (SGLO) to guide the retrieval process. Experiments on document parsing benchmarks show that SCVER improves robustness under reduced input resolution and achieves a better accuracy–efficiency trade-off, demonstrating the effectiveness of on-demand visual evidence retrieval for fine-grained perception.
2025
DocFusion: A Unified Framework for Document Parsing Tasks
Mingxu Chai | Ziyu Shen | Chong Zhang | Yue Zhang | Xiao Wang | Shihan Dou | Jihua Kang | Jiazheng Zhang | Qi Zhang
Findings of the Association for Computational Linguistics: ACL 2025
Mingxu Chai | Ziyu Shen | Chong Zhang | Yue Zhang | Xiao Wang | Shihan Dou | Jihua Kang | Jiazheng Zhang | Qi Zhang
Findings of the Association for Computational Linguistics: ACL 2025
Document parsing involves layout element detection and recognition, essential for extracting information. However, existing methods often employ multiple models for these tasks, leading to increased system complexity and maintenance overhead. While some models attempt to unify detection and recognition, they often fail to address the intrinsic differences in data representations, thereby limiting performance in document processing. Our research reveals that recognition relies on discrete tokens, whereas detection relies on continuous coordinates, leading to challenges in gradient updates and optimization. To bridge this gap, we propose the Gaussian-Kernel Cross-Entropy Loss (GK-CEL), enabling generative frameworks to handle both tasks simultaneously. Building upon GK-CEL, we propose DocFusion, a unified document parsing model with only 0.28B parameters. Additionally, we construct the DocLatex-1.6M dataset to provide high-quality training support. Experimental results show that DocFusion, equipped with GK-CEL, performs competitively across four core document parsing tasks, validating the effectiveness of our unified approach.
Governance in Motion: Co-evolution of Constitutions and AI models for Scalable Safety
Chenhao Huang | Ziyu Shen | Yicong Ren | Huiyuan Zheng | Jiazheng Zhang | Mingxu Chai | Ming Zhang | Shihan Dou | Fan Mo | Jie Shi | Tao Gui | Qi Zhang | Xuanjing Huang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Chenhao Huang | Ziyu Shen | Yicong Ren | Huiyuan Zheng | Jiazheng Zhang | Mingxu Chai | Ming Zhang | Shihan Dou | Fan Mo | Jie Shi | Tao Gui | Qi Zhang | Xuanjing Huang
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Aligning large language models (LLMs) with human preferences is a central challenge for building reliable AI systems. Most existing alignment approaches rely on static signals, such as predefined principles or offline human annotations to guide model behavior toward a fixed approximation of human preferences. However, LLMs can exhibit distributional drift during training, and static alignment mechanisms lack the capacity to adaptively correct misaligned behaviors as they emerge. To address this limitation, we develop a two-stage framework that enables dynamic and continuous alignment. In the first stage, a constitution is continually revised based on observed model behaviors, and models are trained to comply with these evolving principles. In the second stage, this learned constitution is used to guide reinforcement learning, encouraging the model to align with the updated normative signals. We refer to this framework as COCOA: Co-evolution of Constitutions and AI Models. We show that COCOA enables a 7B model to greatly improve safety—raising StrongReject score from 0.741 to 0.935 and Safe-RLHF accuracy from 77.76% to 90.64% without human annotations, reaching performance close to much larger state-of-the-art models.