Yiming Zhang
Author directoryOther people with similar names: Yiming Zhang, Yiming Zhang, Yiming Zhang (CMU)
Unverified author pages with similar names: Yiming Zhang
2026
Fine-Grained Data Ordering Improves Fine-Tuning for Large Language Models
Xiaomeng Hu | Yixuan Tang | Haoze Li | Hao Chen | Qi Zhang | Zhanming Shen | Yiming Zhang | Haobo Wang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2026
Xiaomeng Hu | Yixuan Tang | Haoze Li | Hao Chen | Qi Zhang | Zhanming Shen | Yiming Zhang | Haobo Wang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2026
With the rapid progress of large language models (LLMs), aligning a general-purpose model with downstream tasks through fine-tuning has become a central research focus. Selecting only high-quality examples for training has been shown to be one of the most effective ways to improve fine-tuning performance. However, prior work concentrates almost exclusively on data preprocessing: filtering and cleaning data before training begins. While the order and composition of training data during training have received little fine-grained attention. To fill this gap, our work proposed Fine-Grained Order Fine-Tuning, a fine-grained scheduling method of data order in epochs. Drawing on curriculum-learning principles, FOT defines data difficulty based on the relevance between the data and the model, and then performs dynamic scheduling of the training order in each epoch according to the difficulty. On both large-scale continued pre-training and small-scale supervised fine-tuning experiments, FOT has achieved an average 2.4% improvement over baselines. Our study offers a new perspective on data governance in the fine-tuning phase.
Can LLMs Act as Historians? Evaluating Historical Research Capabilities of LLMs via the Chinese Imperial Examination
Lirong Gao | Zeqing Wang | Yuyan Cai | Jiayi Deng | Yanmei Gu | Yiming Zhang | Jia Zhou | Yanfei Zhang | Junbo Zhao
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Lirong Gao | Zeqing Wang | Yuyan Cai | Jiayi Deng | Yanmei Gu | Yiming Zhang | Jia Zhou | Yanfei Zhang | Junbo Zhao
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
While Large Language Models (LLMs) have increasingly assisted in historical tasks such as text processing, their capacity for professional-level historical reasoning remains underexplored. Existing benchmarks primarily assess basic knowledge breadth or lexical understanding, failing to capture the higher-order skills—such as evidentiary reasoning—that are central to historical research. To fill this gap, we introduce ProHist-Bench, a novel benchmark anchored in the Chinese Imperial Examination (Keju) system—a comprehensive microcosm of East Asian political, social, and intellectual history spanning over 1,300 years. Developed through deep interdisciplinary collaboration, ProHist-Bench features 400 challenging, expert-curated questions across eight dynasties, accompanied by 10,891 fine-grained evaluation rubrics. Through a rigorous evaluation of 18 LLMs, we reveal a significant proficiency gap: even state-of-the-art LLMs struggle with complex historical research questions. We hope ProHist-Bench will facilitate the development of domain-specific reasoning LLMs, advance computational historical research, and further uncover the untapped potential of LLMs. We release ProHist-Bench at https://github.com/inclusionAI/ABench/tree/main/ProHist-Bench.
2025
MRAG: A Modular Retrieval Framework for Time-Sensitive Question Answering
Siyue Zhang | Yuxiang Xue | Yiming Zhang | Xiaobao Wu | Anh Tuan Luu | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Siyue Zhang | Yuxiang Xue | Yiming Zhang | Xiaobao Wu | Anh Tuan Luu | Chen Zhao
Findings of the Association for Computational Linguistics: EMNLP 2025
Understanding temporal concepts and answering time-sensitive questions is crucial yet a challenging task for question-answering systems powered by large language models (LLMs). Existing approaches either update the parametric knowledge of LLMs with new facts, which is resource-intensive and often impractical, or integrate LLMs with external knowledge retrieval (i.e., retrieval-augmented generation). However, off-the-shelf retrievers often struggle to identify relevant documents that require intensive temporal reasoning. To systematically study time-sensitive question answering, we introduce the TempRAGEval benchmark, which repurposes existing datasets by incorporating complex temporal perturbations and gold evidence labels. As anticipated, all existing retrieval methods struggle with these temporal reasoning-intensive questions. We further propose Modular Retrieval (MRAG), a trainless framework that includes three modules: (1) Question Processing that decomposes question into a main content and a temporal constraint; (2) Retrieval and Summarization that retrieves, splits, and summarize evidence passages based on the main content; (3) Semantic-Temporal Hybrid Ranking that scores semantic and temporal relevance separately for each fine-grained evidence. On TempRAGEval, MRAG significantly outperforms baseline retrievers in retrieval performance, leading to further improvements in final answer accuracy.
RPDR: A Round-trip Prediction-Based Data Augmentation Framework for Long-Tail Question Answering
Yiming Zhang | Siyue Zhang | Junbo Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Yiming Zhang | Siyue Zhang | Junbo Zhao | Chen Zhao
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing
Long-tail question answering presents significant challenges for large language models (LLMs) due to their limited ability to acquire and accurately recall less common knowledge. Retrieval-augmented generation (RAG) systems have shown great promise in mitigating this limitation by integrating external retrieval mechanisms. However, dense retrieval models often face the same difficulties when generalizing to rare or niche knowledge. In this study, we introduce RPDR, a novel data augmentation framework that selects high-quality easy-to-learn training data, to enhance dense retrievers. Our approach is built around three core components: synthetic data generation, data selection with Round-Trip prediction to identify easy-to-learn instances, and retriever training with these instances. We evaluate RPDR on two long-tail retrieval benchmarks, PopQA and EntityQuestion, demonstrating substantial improvements over existing retrievers like BM25 and Contriver, especially on extremely long-tail categories. We identify the strengths and limitations of RPDR through detailed human analysis and propose a dynamic routing mechanism to dynamically route queries to specialized retrieval modules to further improve retrieval performance.
2024
RECOST: External Knowledge Guided Data-efficient Instruction Tuning
Qi Zhang | Yiming Zhang | Haobo Wang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2024
Qi Zhang | Yiming Zhang | Haobo Wang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2024
In the current landscape of large language models (LLMs), the process of instruction tuning serves as an essential step. Considering the high computing power overhead, data-efficient instruction tuning was proposed to reduce the training data size in this process, aiming at selecting high-quality instructional data. Nevertheless, we argue that most current data-efficient instruction-tuning methods are highly dependent on the quality of the original instruction-tuning dataset. When it comes to datasets synthesized by LLMs, a common scenario in this field, dirty samples will even be selected with a higher probability than other samples. To address these challenges, we utilized external knowledge (relevant examples or paragraphs) to evaluate those samples synthesized by LLMs with an in-context-based relative predictive entropy. Based on the new metric, we proposed a framework, dubbed as RECOST, which integrates external-knowledge-base re-ranking and diversity-consistent sampling into a single pipeline. Through extensive experiments on several synthetic datasets (Alpaca and Alpaca-gpt4), we demonstrate the effectiveness of our method and achieve even better results with only 1% of the full dataset.
DORY: Deliberative Prompt Recovery for LLM
Lirong Gao | Ru Peng | Yiming Zhang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2024
Lirong Gao | Ru Peng | Yiming Zhang | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2024
Prompt recovery in large language models (LLMs) is crucial for understanding how LLMs work and addressing concerns regarding privacy, copyright, etc. The trend towards inference-only APIs complicates this task by restricting access to essential outputs for recovery. To tackle this challenge, we extract prompt-related information from limited outputs and identify a strong(negative) correlation between output probability-based uncertainty and the success of prompt recovery.This finding led to the development of Deliberative PrOmpt RecoverY (DORY), our novel approach that leverages uncertainty to recover prompts accurately. DORY involves reconstructing drafts from outputs, refining these with hints, and filtering out noise based on uncertainty. Our evaluation shows that DORY outperforms existing baselines across diverse LLMs and prompt benchmarks, improving performance by approximately 10.82% and establishing a new state-of-the-art record in prompt recovery tasks. Significantly, DORY operates using a single LLM without any external resources or model, offering a cost-effective, user-friendly prompt recovery solution.
FinDVer: Explainable Claim Verification over Long and Hybrid-content Financial Documents
Yilun Zhao | Yitao Long | Tintin Jiang | Chengye Wang | Weiyuan Chen | Hongjun Liu | Xiangru Tang | Yiming Zhang | Chen Zhao | Arman Cohan
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Yilun Zhao | Yitao Long | Tintin Jiang | Chengye Wang | Weiyuan Chen | Hongjun Liu | Xiangru Tang | Yiming Zhang | Chen Zhao | Arman Cohan
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
We introduce FinDVer, a comprehensive benchmark specifically designed to evaluate the explainable claim verification capabilities of LLMs in the context of understanding and analyzing long, hybrid-content financial documents. FinDVer contains 4,000 expert-annotated examples across four subsets, each focusing on a type of scenario that frequently arises in real-world financial domains. We assess a broad spectrum of 25 LLMs under long-context and RAG settings. Our results show that even the current best-performing system (i.e., GPT-4o) significantly lags behind human experts. Our detailed findings and insights highlight the strengths and limitations of existing LLMs in this new task. We believe FinDVer can serve as a valuable benchmark for evaluating LLM capabilities in claim verification over complex, expert-domain documents.
Embedding and Gradient Say Wrong: A White-Box Method for Hallucination Detection
Xiaomeng Hu | Yiming Zhang | Ru Peng | Haozhe Zhang | Chenwei Wu | Gang Chen | Junbo Zhao
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
Xiaomeng Hu | Yiming Zhang | Ru Peng | Haozhe Zhang | Chenwei Wu | Gang Chen | Junbo Zhao
Proceedings of the 2024 Conference on Empirical Methods in Natural Language Processing
In recent years, large language models (LLMs) have achieved remarkable success in the field of natural language generation. Compared to previous small-scale models, they are capable of generating fluent output based on the provided prefix or prompt. However, one critical challenge — the hallucination problem — remains to be resolved. Generally, the community refers to the undetected hallucination scenario where the LLMs generate text unrelated to the input text or facts. In this study, we intend to model the distributional distance between the regular conditional output and the unconditional output, which is generated without a given input text. Based upon Taylor Expansion for this distance at the output probability space, our approach manages to leverage the embedding and first-order gradient information. The resulting approach is plug-and-play that can be easily adapted to any autoregressive LLM. On the hallucination benchmarks HADES and other datasets, our approach achieves state-of-the-art performance.
2022
Towards Unifying the Label Space for Aspect- and Sentence-based Sentiment Analysis
Yiming Zhang | Min Zhang | Sai Wu | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2022
Yiming Zhang | Min Zhang | Sai Wu | Junbo Zhao
Findings of the Association for Computational Linguistics: ACL 2022
The aspect-based sentiment analysis (ABSA) is a fine-grained task that aims to determine the sentiment polarity towards targeted aspect terms occurring in the sentence. The development of the ABSA task is very much hindered by the lack of annotated data. To tackle this, the prior works have studied the possibility of utilizing the sentiment analysis (SA) datasets to assist in training the ABSA model, primarily via pretraining or multi-task learning. In this article, we follow this line, and for the first time, we manage to apply the Pseudo-Label (PL) method to merge the two homogeneous tasks. While it seems straightforward to use generated pseudo labels to handle this case of label granularity unification for two highly related tasks, we identify its major challenge in this paper and propose a novel framework, dubbed as Dual-granularity Pseudo Labeling (DPL). Further, similar to PL, we regard the DPL as a general framework capable of combining other prior methods in the literature. Through extensive experiments, DPL has achieved state-of-the-art performance on standard benchmarks surpassing the prior work significantly.
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Co-authors
- Junbo Zhao 7
- Chen Zhao 3
- Lirong Gao 2
- Xiaomeng Hu 2
- Ru Peng 2
- Haobo Wang 2
- Qi Zhang 2
- Siyue Zhang 2
- Yuyan Cai 1
- Gang Chen 1
- Hao Chen 1
- Weiyuan Chen 1
- Arman Cohan 1
- Jiayi Deng 1
- Yanmei Gu 1
- Tintin Jiang 1
- Haoze Li 1
- Hongjun Liu 1
- Yitao Long 1
- Zhanming Shen 1
- Xiangru Tang 1
- Yixuan Tang 1
- Luu Anh Tuan 1
- Chengye Wang 1
- Zeqing Wang 1
- Chenwei Wu 1
- Sai Wu 1
- Xiaobao Wu 1
- Yuxiang Xue 1
- Haozhe Zhang 1
- Min Zhang 1
- Yanfei Zhang 1
- Yilun Zhao 1
- Jia Zhou 1