Zongyu Wu
2026
Image Corruption-Inspired Membership Inference Attacks against Large Vision-Language Models
Zongyu Wu | Minhua Lin | Zhiwei Zhang | Fali Wang | Xianren Zhang | Xiang Zhang | Suhang Wang
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Zongyu Wu | Minhua Lin | Zhiwei Zhang | Fali Wang | Xianren Zhang | Xiang Zhang | Suhang Wang
Proceedings of the 19th Conference of the European Chapter of the Association for Computational Linguistics (Volume 1: Long Papers)
Large vision-language models (LVLMs) have demonstrated outstanding performance in many downstream tasks. However, LVLMs are trained on large-scale datasets, which can pose privacy risks if training images contain sensitive information. Therefore, it is important to detect whether an image is used to train the LVLM. Recent studies have investigated membership inference attacks (MIAs) against LVLMs, including detecting image-text pairs and single-modality content. In this work, we focus on detecting whether a target image is used to train the target LVLM. We design simple yet effective Image Corruption-Inspired Membership Inference Attacks (ICIMIA) against LVLMs, which are inspired by LVLM’s different sensitivity to image corruption for member and non-member images. We first perform an MIA method under the white-box setting, where we can obtain the embeddings of the image through the vision part of the target LVLM. The attacks are based on the embedding similarity between the image and its corrupted version. We further explore a more practical scenario where we have no knowledge about target LVLMs and we can only query the target LVLMs with an image and a textual instruction. We then conduct the attack by utilizing the output text embeddings’ similarity. Experiments on existing datasets validate the effectiveness of our proposed methods under those two different settings.
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.
2025
Divide-Verify-Refine: Can LLMs Self-align with Complex Instructions?
Xianren Zhang | Xianfeng Tang | Hui Liu | Zongyu Wu | Qi He | Dongwon Lee | Suhang Wang
Findings of the Association for Computational Linguistics: ACL 2025
Xianren Zhang | Xianfeng Tang | Hui Liu | Zongyu Wu | Qi He | Dongwon Lee | Suhang Wang
Findings of the Association for Computational Linguistics: ACL 2025
Recent studies show LLMs struggle with complex instructions involving multiple constraints (e.g., length, format, sentiment). Existing research enhances open-source LLMs using closed-source guidance (e.g., GPT-4), but this heavily relies on generated data quality. An alternative is leveraging LLMs’ self-correction to refine responses for better constraint adherence. However, this is limited by the feedback quality, as we found LLMs cannot generate reliable feedback or detect errors. Moreover, the self-correction effectiveness relies on few-shot examples illustrating response modifications. As constraints in complex instructions are diverse, manually crafting such examples for each constraint type can be labor-intensive and sub-optimal. To address these two challenges, we propose the Divide-Verify-Refine (DVR) framework with three steps: (1) Divide complex instructions into single constraints and prepare appropriate tools; (2) Verify responses using tools that provide rigorous check and textual guidance (e.g., Python scripts for format checks or pre-trained classifiers for content analysis); (3) Refine: To maximize refinement effectiveness, we propose dynamic few-shot prompting, where a refinement repository collects successful refinements, and these examples are selectively retrieved for future refinements. Recognizing the lack of complexity in existing datasets, we create a new dataset of complex instructions. DVR doubles Llama3.1-8B’s constraint adherence and triples Mistral-7B’s performance.
2024
Universal Prompt Optimizer for Safe Text-to-Image Generation
Zongyu Wu | Hongcheng Gao | Yueze Wang | Xiang Zhang | Suhang Wang
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Zongyu Wu | Hongcheng Gao | Yueze Wang | Xiang Zhang | Suhang Wang
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Text-to-Image (T2I) models have shown great performance in generating images based on textual prompts. However, these models are vulnerable to unsafe input to generate unsafe content like sexual, harassment and illegal-activity images. Existing studies based on image checker, model fine-tuning and embedding blocking are impractical in real-world applications. Hence, we propose the first universal **p**rompt **o**ptimizer for **s**afe T2**I** (**POSI**) generation in black-box scenario. We first construct a dataset consisting of toxic-clean prompt pairs by GPT-3.5 Turbo. To guide the optimizer to have the ability of converting toxic prompt to clean prompt while preserving semantic information, we design a novel reward function measuring toxicity and text alignment of generated images and train the optimizer through Proximal Policy Optimization. Experiments show that our approach can effectively reduce the likelihood of various T2I models in generating inappropriate images, with no significant impact on text alignment. It is also flexible to be combined with methods to achieve better performance. Our code is available at [https://github.com/wzongyu/POSI](https://github.com/wzongyu/POSI).