Chen Han
Author directoryAlso published as: Han Chen
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2026
TempCloze: Can Video-LLMs Identify the Missing Middle?
Wenqi Pei | Henry Hengyuan Zhao | Yilai Liu | Jiahao Meng | Chen Han | Ziyu Wang | Hongyang Du
Findings of the Association for Computational Linguistics: EMNLP 2026
Wenqi Pei | Henry Hengyuan Zhao | Yilai Liu | Jiahao Meng | Chen Han | Ziyu Wang | Hongyang Du
Findings of the Association for Computational Linguistics: EMNLP 2026
Temporal reasoning benchmarks for Video-LLMs are often mediated by language, leaving room for linguistic shortcuts from option wording, answer correlations, or language priors. To reduce such shortcuts, we introduce TempCloze, a video cloze benchmark for evaluating visual temporal reasoning in Video-LLMs. Given the beginning and ending clips of a video, models must identify the true missing middle from four candidates. TempCloze contains 1,521 carefully filtered videos from seven sources, mainly long-take and egocentric videos. We construct same-source distractors along three dimensions: Semantic asks what event should happen, Alignment probes when it should occur, and Progression tests how it should unfold, while shared scenes and objects reduce appearance cues. Our evaluation of 10 proprietary and 21 open-source Video-LLMs reveals Alignment as the primary bottleneck: models often recognize plausible semantic content and local event progression but struggle with temporal alignment. We further conduct error pattern and behavioral sensitivity analyses on TempCloze-Mixed and TempCloze-Hard with four representative models to examine where errors arise and how candidate order, context direction, visible span, frame density, and test-time scaling influence model choices.
RW-TTT: Batched Serving for Request-Owned Test-Time Training State
Jian Yang | Zhizhuo Kou | Chen Han | Hao Zhang | Yao Tian | Sirui Han | Yike Guo
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Jian Yang | Zhizhuo Kou | Chen Han | Hao Zhang | Yao Tian | Sirui Han | Yike Guo
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Test-time training (TTT) adapts an LLM during generation by reading and updating request-owned state, such as fast weights, low-rank deltas, or streaming learner state. This breaks batched LLM serving, which assumes shared static weights: serial execution is correct but slow, while naive batching can corrupt request state. We formulate this problem as read-write TTT serving and present RW-TTT, which tags each decode step with its owner, version, and READ/WRITE effect, batches only compatible phases, and commits updates only to the owner. On one GPU with eight fast-weight In-Place-TTT streams, RW-TTT reaches 274.61 aggregate tok/s, 9.31× over sequential serving and 3.44× over memory-matched independent replicas. It preserves behavior on RULER, a long-context benchmark, and passes owner/version checks.
ROSE: An Intent-Centered Evaluation Metric for NL2SQL
Wenqi Pei | Shizheng Hou | Boyan Li | Chen Han | Zhichao Shi | Yuyu Luo
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Wenqi Pei | Shizheng Hou | Boyan Li | Chen Han | Zhichao Shi | Yuyu Luo
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Execution Accuracy (EX), the widely used metric for evaluating the effectiveness of Natural Language to SQL (NL2SQL) solutions, is becoming increasingly unreliable. It is sensitive to syntactic variation, ignores that questions may admit multiple interpretations, and is easily misled by erroneous ground-truth SQL. To address this, we introduce ROSE, an intent-centered metric that focuses on whether the predicted SQL answers the question, rather than consistency with the ground-truth SQL under the reference-dependent paradigm. ROSE employs an adversarial Prover-Refuter cascade: SQL Prover assesses the semantic correctness of a predicted SQL against the user’s intent independently, while Adversarial Refuter uses the ground-truth SQL as evidence to challenge and refine this judgment. On our expert-aligned validation set ROSE-VEC, ROSE achieves the best agreement with human experts, outperforming the next-best metric by nearly 24% in Cohen’s Kappa. We also conduct a large-scale re-evaluation of 19 NL2SQL methods, revealing four valuable insights. We release ROSE and ROSE-VEC to facilitate more reliable NL2SQL research.
2025
Feather-SQL: A Lightweight NL2SQL Framework with Dual-Model Collaboration Paradigm for Small Language Models
Wenqi Pei | Hailing Xu | Henry Hengyuan Zhao | Shizheng Hou | Han Chen | Zining Zhang | Pingyi Luo | Bingsheng He
Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Wenqi Pei | Hailing Xu | Henry Hengyuan Zhao | Shizheng Hou | Han Chen | Zining Zhang | Pingyi Luo | Bingsheng He
Proceedings of the 14th International Joint Conference on Natural Language Processing and the 4th Conference of the Asia-Pacific Chapter of the Association for Computational Linguistics
Natural Language to SQL (NL2SQL) has seen significant advancements with large language models (LLMs). However, these models often depend on closed-source methods and high computational resources, posing challenges in data privacy and deployment. In contrast, small language models (SLMs) struggle with NL2SQL tasks, exhibiting poor performance and incompatibility with existing frameworks. To address these issues, we introduce Feather-SQL, a new lightweight framework tailored for SLMs. Feather-SQL improves SQL executability and accuracy through: (i) schema pruning and linking, (ii) multi-path and multi-candidate generation. Additionally, we introduce 1+1 Model Collaboration Paradigm, which pairs a strong general-purpose chat model with a fine-tuned SQL model, combining strong analytical reasoning with high-precision SQL generation. Experimental results on BIRD demonstrate that Feather-SQL improves NL2SQL performance on SLMs, with around 10% boost for models without fine-tuning. The proposed paradigm raises the accuracy ceiling of SLMs to 54.76%, highlighting its effectiveness.