Qian Zhang


2025

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CityNavAgent: Aerial Vision-and-Language Navigation with Hierarchical Semantic Planning and Global Memory
Weichen Zhang | Chen Gao | Shiquan Yu | Ruiying Peng | Baining Zhao | Qian Zhang | Jinqiang Cui | Xinlei Chen | Yong Li
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)

Aerial vision-and-language navigation (VLN) — requiring drones to interpret natural language instructions and navigate complex urban environments — emerges as a critical embodied AI challenge that bridges human-robot interaction, 3D spatial reasoning, and real-world deployment. Although existing ground VLN agents achieved notable results in indoor and outdoor settings, they struggle in aerial VLN due to the absence of predefined navigation graphs and the exponentially expanding action space in long-horizon exploration. In this work, we propose CityNavAgent, a large language model (LLM)-empowered agent that significantly reduces the navigation complexity for urban aerial VLN. Specifically, we design a hierarchical semantic planning module (HSPM) that decomposes the long-horizon task into sub-goals with different semantic levels. The agent reaches the target progressively by achieving sub-goals with different capacities of the LLM. Additionally, a global memory module storing historical trajectories into a topological graph is developed to simplify navigation for visited targets. Extensive benchmark experiments show that our method achieves state-of-the-art performance with significant improvement. Further experiments demonstrate the effectiveness of different modules of CityNavAgent for aerial VLN in continuous city environments.

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ScEdit: Script-based Assessment of Knowledge Editing
Xinye Li | Zunwen Zheng | Qian Zhang | Dekai Zhuang | Jiabao Kang | Liyan Xu | Qingbin Liu | Xi Chen | Zhiying Tu | Dianhui Chu | Dianbo Sui
Findings of the Association for Computational Linguistics: ACL 2025

Knowledge Editing (KE) has gained increasing attention, yet current KE tasks remain relatively simple. Under current evaluation frameworks, many editing methods achieve exceptionally high scores, sometimes nearing perfection. However, few studies integrate KE into real-world application scenarios (e.g., recent interest in LLM-as-agent). To support our analysis, we introduce a novel script-based benchmark – ScEdit (Script-based Knowledge Editing Benchmark) – which encompasses both counterfactual and temporal edits. We integrate token-level and text-level evaluation methods, comprehensively analyzing existing KE techniques. The benchmark extends traditional fact-based (“What”-type question) evaluation to action-based (“How”-type question) evaluation. We observe that all KE methods exhibit a drop in performance on established metrics and face challenges on text-level metrics, indicating a challenging task. Our benchmark is available at https://github.com/asdfo123/ScEdit.

2024

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Document Hashing with Multi-Grained Prototype-Induced Hierarchical Generative Model
Qian Zhang | Qinliang Su | Jiayang Chen | Zhenpeng Song
Findings of the Association for Computational Linguistics: EMNLP 2024

Document hashing plays a crucial role in large-scale information retrieval. However, existing unsupervised document hashing methods merely consider flat semantics of documents, resulting in the inability of preserving hierarchical semantics in hash codes. In this paper, we propose a hierarchical generative model that can model and leverage the hierarchical structure of semantics. Specifically, we introduce hierarchical prototypes into the model to construct a hierarchical prior distribution, which is integrated into the variational auto-encoder (VAE) framework, enabling the model to produce hash codes preserving rough hierarchical semantics. To further promote the preservation of hierarchical structure, we force the hash code to preserve as much semantic information as possible via contrastive learning, which exploits the hierarchical pseudo labels produced during VAE training. Extensive experiments on three benchmarks outperform all baseline methods, demonstrating the superiority of our proposed model on both hierarchical datasets and flat datasets.

2023

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Improving Visual-Semantic Embedding with Adaptive Pooling and Optimization Objective
Zijian Zhang | Chang Shu | Ya Xiao | Yuan Shen | Di Zhu | Youxin Chen | Jing Xiao | Jey Han Lau | Qian Zhang | Zheng Lu
Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics

Visual-Semantic Embedding (VSE) aims to learn an embedding space where related visual and semantic instances are close to each other. Recent VSE models tend to design complex structures to pool visual and semantic features into fixed-length vectors and use hard triplet loss for optimization. However, we find that: (1) combining simple pooling methods is no worse than these sophisticated methods; and (2) only considering the most difficult-to-distinguish negative sample leads to slow convergence and poor Recall@K improvement. To this end, we propose an adaptive pooling strategy that allows the model to learn how to aggregate features through a combination of simple pooling methods. We also introduce a strategy to dynamically select a group of negative samples to make the optimization converge faster and perform better. Experimental results on Flickr30K and MS-COCO demonstrate that a standard VSE using our pooling and optimization strategies outperforms current state-of-the-art systems (at least 1.0% on the metrics of recall) in image-to-text and text-to-image retrieval. Source code of our experiments is available at https://github.com/96-Zachary/vse_2ad .

2020

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OPPO’s Machine Translation System for the IWSLT 2020 Open Domain Translation Task
Qian Zhang | Xiaopu Li | Dawei Dang | Tingxun Shi | Di Ai | Zhengshan Xue | Jie Hao
Proceedings of the 17th International Conference on Spoken Language Translation

In this paper, we demonstrate our machine translation system applied for the Chinese-Japanese bidirectional translation task (aka. open domain translation task) for the IWSLT 2020. Our model is based on Transformer (Vaswani et al., 2017), with the help of many popular, widely proved effective data preprocessing and augmentation methods. Experiments show that these methods can improve the baseline model steadily and significantly.

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OPPO’s Machine Translation Systems for WMT20
Tingxun Shi | Shiyu Zhao | Xiaopu Li | Xiaoxue Wang | Qian Zhang | Di Ai | Dawei Dang | Xue Zhengshan | Jie Hao
Proceedings of the Fifth Conference on Machine Translation

In this paper we demonstrate our (OPPO’s) machine translation systems for the WMT20 Shared Task on News Translation for all the 22 language pairs. We will give an overview of the common aspects across all the systems firstly, including two parts: the data preprocessing part will show how the data are preprocessed and filtered, and the system part will show our models architecture and the techniques we followed. Detailed information, such as training hyperparameters and the results generated by each technique will be depicted in the corresponding subsections. Our final submissions ranked top in 6 directions (English Czech, English Russian, French German and Tamil English), third in 2 directions (English German, English Japanese), and fourth in 2 directions (English Pashto and and English Tamil).