Junfeng Ran


2025

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LongAttn: Selecting Long-context Training Data via Token-level Attention
Longyun Wu | Dawei Zhu | Guangxiang Zhao | Zhuocheng Yu | Junfeng Ran | Xiangyu Wong | Lin Sun | Sujian Li
Findings of the Association for Computational Linguistics: ACL 2025

With the development of large language models (LLMs), there has been an increasing need for significant advancements in handling long contexts. To enhance long-context capabilities, constructing high-quality training data with **long-range dependencies** is crucial. Existing methods to select long-context data often rely on sentence-level analysis,which can be greatly optimized in both performance and efficiency. In this paper, we propose a novel token-level framework, ​**LongAttn**​, which leverages the self-attention mechanism of LLMs to measure the **long-range dependencies** for the data. By calculating token-level dependency strength and distribution uniformity of token scores, LongAttn effectively quantifies ​**long-range dependencies**​, enabling more accurate and efficient data selection. We filter **LongABC-32K** from open-source long-context datasets (ArXiv, Book, and Code). Through our comprehensive experiments, LongAttn has demonstrated its excellent ​**effectiveness**​, ​**scalability**​, and ​**efficiency**​. We will release our code and the high-quality long-context dataset **LongABC-32K** in the future.

2024

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FaGANet: An Evidence-Based Fact-Checking Model with Integrated Encoder Leveraging Contextual Information
Weiyao Luo | Junfeng Ran | Zailong Tian | Sujian Li | Zhifang Sui
Proceedings of the 2024 Joint International Conference on Computational Linguistics, Language Resources and Evaluation (LREC-COLING 2024)

In the face of the rapidly growing spread of false and misleading information in the real world, manual evidence-based fact-checking efforts become increasingly challenging and time-consuming. In order to tackle this issue, we propose FaGANet, an automated and accurate fact-checking model that leverages the power of sentence-level attention and graph attention network to enhance performance. This model adeptly integrates encoder-only models with graph attention network, effectively fusing claims and evidence information for accurate identification of even well-disguised data. Experiment results showcase the significant improvement in accuracy achieved by our FaGANet model, as well as its state-of-the-art performance in the evidence-based fact-checking task. We release our code and data in https://github.com/WeiyaoLuo/FaGANet.