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arXiv 2403.05798cs.LG
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$S^2$IP-LLM:利用大语言模型进行语义空间启发的提示学习以实现时间序列预测

$\textbf{S}^2$IP-LLM: Semantic Space Informed Prompt Learning with LLM for Time Series Forecasting

School of Computing, University of Connecticut(康涅狄格大学计算机学院);Morgan Stanley(摩根士丹利)

Zijie Pan, Yushan Jiang, Sahil Garg, Anderson Schneider, Yuriy Nevmyvaka, Dongjin Song

AI总结:

本文提出$S^2$IP-LLM,通过跨模态分词、语义锚点对齐与提示检索,将LLM预训练语义空间用于时间序列预测,并在多个基准上验证其优于现有方法。

摘要:

近来,人们越来越关注将预训练大语言模型(LLM)用于各种时间序列应用。然而,LLM通过预训练建立的语义空间仍未得到充分探索,而该空间可能有助于产生更具区分性和信息量的表示,从而促进时间序列预测。为此,我们提出了利用LLM的语义空间启发提示学习方法(Semantic Space Informed Prompt learning with LLM,$S^2$IP-LLM),将预训练语义空间与时间序列嵌入空间对齐,并基于从联合空间中学习到的提示执行时间序列预测。我们首先设计了一个专为跨模态对齐定制的分词模块,该模块显式拼接分解后的时间序列成分的补丁,以创建有效编码时间动态的嵌入。接下来,我们利用预训练词元嵌入推导语义锚点,并通过最大化联合空间中的余弦相似度,将选定的锚点与时间序列嵌入对齐。这样,$S^2$IP-LLM可以检索相关语义锚点作为提示,为表现出不同时间动态的时间序列提供强指标(上下文)。通过在多个基准数据集上的充分实证研究,我们证明所提出的$S^2$IP-LLM能够取得优于最先进基线的预测性能。此外,我们的消融研究和可视化验证了由语义空间启发的提示学习的必要性。

英文摘要:

Recently, there has been a growing interest in leveraging pre-trained large language models (LLMs) for various time series applications. However, the semantic space of LLMs, established through the pre-training, is still underexplored and may help yield more distinctive and informative representations to facilitate time series forecasting. To this end, we propose Semantic Space Informed Prompt learning with LLM ($S^2$IP-LLM) to align the pre-trained semantic space with time series embeddings space and perform time series forecasting based on learned prompts from the joint space. We first design a tokenization module tailored for cross-modality alignment, which explicitly concatenates patches of decomposed time series components to create embeddings that effectively encode the temporal dynamics. Next, we leverage the pre-trained word token embeddings to derive semantic anchors and align selected anchors with time series embeddings by maximizing the cosine similarity in the joint space. This way, $S^2$IP-LLM can retrieve relevant semantic anchors as prompts to provide strong indicators (context) for time series that exhibit different temporal dynamics. With thorough empirical studies on multiple benchmark datasets, we demonstrate that the proposed $S^2$IP-LLM can achieve superior forecasting performance over state-of-the-art baselines. Furthermore, our ablation studies and visualizations verify the necessity of prompt learning informed by semantic space.

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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