Fengyu Cai
Author directory2026
CoQuIR: A Comprehensive Benchmark for Code Quality-Aware Information Retrieval
Jiahui Geng | Fengyu Cai | Shaobo Cui | Qing Li | Liangwei Chen | Chenyang Lyu | Haonan Li | Derui Zhu | Alexander Pretschner | Heinz Koeppl | Fakhri Karray
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Jiahui Geng | Fengyu Cai | Shaobo Cui | Qing Li | Liangwei Chen | Chenyang Lyu | Haonan Li | Derui Zhu | Alexander Pretschner | Heinz Koeppl | Fakhri Karray
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Code retrieval is vital to modern software engineering as it boosts reuse and speeds up debugging. However, current benchmarks primarily emphasize functional relevance while neglecting code quality. To address this gap, we introduce CoQuIR, the first large-scale, multilingual benchmark specifically designed to evaluate quality-aware code retrieval across four critical dimensions: correctness, efficiency, security, and maintainability. CoQuIR includes fine-grained quality annotations over 42,725 queries and 134,907 code snippets in 11 programming languages. Evaluating 23 retrievers (both open-source and proprietary) shows that even state-of-the-art models often fail to separate buggy or insecure code from robust counterparts. We further investigate methods for explicitly training retrievers to recognize code quality, demonstrating that quality-aware metrics can be improved without loss of semantic relevance; downstream code generation benefits from these gains. CoQuIR underscores the importance of embedding quality signals into retrieval systems as a crucial component for more trustworthy developer tools.
Crayotter: Traceable Multi-Agent Workflows for Long-Form Video Editing
Lecheng Yan | Yichong Zhang | Xiantao Xu | Jianze Lin | Ben Pan | Xiaoyu Zheng | Jiawei Qian | Anqi Wu | Jiahui Geng | Ruizhe Li | Fengyu Cai | Jingcheng Niu | Raymond Li | Wenxi Li | Chenyang Lyu
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics: System Demonstrations
Lecheng Yan | Yichong Zhang | Xiantao Xu | Jianze Lin | Ben Pan | Xiaoyu Zheng | Jiawei Qian | Anqi Wu | Jiahui Geng | Ruizhe Li | Fengyu Cai | Jingcheng Niu | Raymond Li | Wenxi Li | Chenyang Lyu
Proceedings of the 15th International Joint Conference on Natural Language Processing and the 5th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics: System Demonstrations
Long-form video editing over heterogeneous footage requires agents to coordinate source selection, multimodal analysis, timeline construction, narration and subtitle alignment, rendering, and revision while exposing intermediate state for inspection and repair. We present **Crayotter**, an open-source multimodal multi-agent demo system for prompt-driven long-form video editing. Crayotter organizes production around coverage-aware material preparation, artifact-grounded editing research, and tool-grounded timeline execution. Across these stages, retrieval reports, video analyses, editing blueprints, scheduler events, tool calls, intermediate renders, and final exports are treated as first-class artifacts rather than hidden transient state. The workbench supports local assets, agent-assisted retrieval, progress monitoring, artifact preview, failure diagnosis, interrupted-job resumption, and resource-aware asynchronous execution for long-running workflows. In a 23-theme evaluation, Crayotter achieves the highest human overall score (3.40/5) among the compared systems, with its largest margins in theme alignment, narrative coherence, and editing smoothness. These results show that long-horizon video editing agents can be made traceable, inspectable, and practically controllable through observable production artifacts.
2025
MoR: Better Handling Diverse Queries with a Mixture of Sparse, Dense, and Human Retrievers
Jushaan Singh Kalra | Xinran Zhao | To Eun Kim | Fengyu Cai | Fernando Diaz | Tongshuang Wu
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Jushaan Singh Kalra | Xinran Zhao | To Eun Kim | Fengyu Cai | Fernando Diaz | Tongshuang Wu
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Retrieval-augmented Generation (RAG) is powerful, but its effectiveness hinges on which retrievers we use and how. Different retrievers offer distinct, often complementary signals: BM25 captures lexical matches; dense retrievers, semantic similarity. Yet in practice, we typically fix a single retriever based on heuristics, which fails to generalize across diverse information needs. Can we dynamically select and integrate multiple retrievers for each individual query, without the need for manual selection? In our work, we validate this intuition with quantitative analysis and introduce a mixture of retrievers: a zero-shot, weighted combination of heterogeneous retrievers. Extensive experiments show that such mixtures are effective and efficient: Despite totaling just 0.8B parameters, this mixture outperforms every individual retriever and even larger 7B models—by +10.8% and +3.9% on average, respectively. Further analysis also shows that this mixture framework can help incorporate specialized non-oracle human information sources as retrievers to achieve good collaboration, with a 58.9% relative performance improvement over simulated humans alone.
2024
A Survey of Confidence Estimation and Calibration in Large Language Models
Jiahui Geng | Fengyu Cai | Yuxia Wang | Heinz Koeppl | Preslav Nakov | Iryna Gurevych
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Jiahui Geng | Fengyu Cai | Yuxia Wang | Heinz Koeppl | Preslav Nakov | Iryna Gurevych
Proceedings of the 2024 Conference of the North American Chapter of the Association for Computational Linguistics: Human Language Technologies (Volume 1: Long Papers)
Large language models (LLMs) have demonstrated remarkable capabilities across a wide range of tasks in various domains. Despite their impressive performance, they can be unreliable due to factual errors in their generations. Assessing their confidence and calibrating them across different tasks can help mitigate risks and enable LLMs to produce better generations. There has been a lot of recent research aiming to address this, but there has been no comprehensive overview to organize it and to outline the main lessons learned. The present survey aims to bridge this gap. In particular, we outline the challenges and we summarize recent technical advancements for LLM confidence estimation and calibration. We further discuss their applications and suggest promising directions for future work.
GeoHard: Towards Measuring Class-wise Hardness through Modelling Class Semantics
Fengyu Cai | Xinran Zhao | Hongming Zhang | Iryna Gurevych | Heinz Koeppl
Findings of the Association for Computational Linguistics: ACL 2024
Fengyu Cai | Xinran Zhao | Hongming Zhang | Iryna Gurevych | Heinz Koeppl
Findings of the Association for Computational Linguistics: ACL 2024
MixGR: Enhancing Retriever Generalization for Scientific Domain through Complementary Granularity
Fengyu Cai | Xinran Zhao | Tong Chen | Sihao Chen | Hongming Zhang | Iryna Gurevych | Heinz Koeppl
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Fengyu Cai | Xinran Zhao | Tong Chen | Sihao Chen | Hongming Zhang | Iryna Gurevych | Heinz Koeppl
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
2021
Self-training Improves Pre-training for Few-shot Learning in Task-oriented Dialog Systems
Fei Mi | Wanhao Zhou | Lingjing Kong | Fengyu Cai | Minlie Huang | Boi Faltings
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing
Fei Mi | Wanhao Zhou | Lingjing Kong | Fengyu Cai | Minlie Huang | Boi Faltings
Proceedings of the 2021 Conference on Empirical Methods in Natural Language Processing
As the labeling cost for different modules in task-oriented dialog (ToD) systems is expensive, a major challenge is to train different modules with the least amount of labeled data. Recently, large-scale pre-trained language models, have shown promising results for few-shot learning in ToD. In this paper, we devise a self-training approach to utilize the abundant unlabeled dialog data to further improve state-of-the-art pre-trained models in few-shot learning scenarios for ToD systems. Specifically, we propose a self-training approach that iteratively labels the most confident unlabeled data to train a stronger Student model. Moreover, a new text augmentation technique (GradAug) is proposed to better train the Student by replacing non-crucial tokens using a masked language model. We conduct extensive experiments and present analyses on four downstream tasks in ToD, including intent classification, dialog state tracking, dialog act prediction, and response selection. Empirical results demonstrate that the proposed self-training approach consistently improves state-of-the-art pre-trained models (BERT, ToD-BERT) when only a small number of labeled data are available.
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Co-authors
- Heinz Koeppl 4
- Jiahui Geng 3
- Iryna Gurevych 3
- Xinran Zhao 3
- Chenyang Lyu 2
- Hongming Zhang 2
- Liangwei Chen 1
- Sihao Chen 1
- Tong Chen 1
- Shaobo Cui 1
- Fernando Diaz 1
- Boi Faltings 1
- Minlie Huang 1
- Jushaan Singh Kalra 1
- Fakhri Karray 1
- To Eun Kim 1
- Lingjing Kong 1
- Haonan Li 1
- Qing Li 1
- Raymond Li 1
- Ruizhe Li 1
- Wenxi Li 1
- Jianze Lin 1
- Fei Mi 1
- Preslav Nakov 1
- Jingcheng Niu 1
- Ben Pan 1
- Alexander Pretschner 1
- Jiawei Qian 1
- Yuxia Wang 1
- Anqi Wu 1
- Tongshuang Wu 1
- Xiantao Xu 1
- Lecheng Yan 1
- Yichong Zhang 1
- Xiaoyu Zheng 1
- Wanhao Zhou 1
- Derui Zhu 1