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arXiv 2601.03464cs.CL
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提示低估了LLM在时间序列分类中的能力

Prompting Underestimates LLM Capability for Time Series Classification

The University of Texas at San Antonio(德克萨斯大学圣安东尼奥分校)

Dan Schumacher, Erfan Nourbakhsh, Rocky Slavin, Anthony Rios

AI总结:

研究通过对比提示输出与线性探针,揭示LLM在时间序列分类中的实际能力被提示评估低估,且早期Transformer层能有效捕捉时间序列信息。

摘要:

基于提示的评估表明,大型语言模型(LLMs)在时间序列分类中表现不佳,引发了对其是否编码有意义的时间结构的质疑。我们通过直接比较提示输出与在同一内部表示上的线性探针,展示了这一结论反映了提示生成的限制,而非模型的表征能力。尽管零样本提示表现接近偶然,线性探针将平均F1从0.15-0.26提升到0.61-0.67,经常匹配或超过专门的时间序列模型。分层分析进一步显示,类别区分性的时间序列信息在早期Transformer层中出现,并通过视觉和多模态输入得到放大。这些结果表明,LLMs内部表示与提示评估揭示的内容之间存在系统性不匹配,导致当前评估低估了它们的时间序列理解能力。

英文摘要:

Prompt-based evaluations suggest that large language models (LLMs) perform poorly on time series classification, raising doubts about whether they encode meaningful temporal structure. We show that this conclusion reflects limitations of prompt-based generation rather than the model's representational capacity by directly comparing prompt outputs with linear probes over the same internal representations. While zero-shot prompting performs near chance, linear probes improve average F1 from 0.15-0.26 to 0.61-0.67, often matching or exceeding specialized time series models. Layer-wise analyses further show that class-discriminative time series information emerges in early transformer layers and is amplified by visual and multimodal inputs. Together, these results demonstrate a systematic mismatch between what LLMs internally represent and what prompt-based evaluation reveals, leading current evaluations to underestimate their time series understanding.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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