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arXiv 2306.06930cs.LG
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局部化自适应时空图神经网络

Localised Adaptive Spatial-Temporal Graph Neural Network

Nanchang University(南昌大学);University of Macau(澳门大学);City University of Hong Kong(香港城市大学);ETH Zurich(苏黎世联邦理工学院)

Wenying Duan, Xiaoxi He, Zimu Zhou, Lothar Thiele, Hong Rao

AI总结:

该研究提出自适应图稀疏化算法实现自适应时空图神经网络的局部化,发现空间依赖信息推理时冗余但训练时关键,为降低计算开销、实现分布式部署提供可能。

摘要:

时空图模型被广泛用于对时空依赖关系进行抽象与建模。在本研究中,我们提出如下问题:我们能否实现时空图模型的局部化,以及能在多大程度上实现?我们的研究范围限定为当前最先进的模型架构——自适应时空图神经网络(ASTGNNs)。我们的局部化方法核心是对空间图邻接矩阵进行稀疏化。为此,我们提出了自适应图稀疏化(Adaptive Graph Sparsification,AGS)算法,该算法能够将ASTGNNs的局部化推进到极致程度(完全局部化)。我们将AGS应用于两种不同的ASTGNN架构以及9个时空数据集。值得注意的是,我们发现ASTGNNs中的空间图可以被稀疏化99.5%以上,且测试精度不会出现任何下降。此外,即便ASTGNNs被完全局部化,变为无图的纯时序模型,在大多数测试数据集上我们都未观测到精度下降,仅在剩余数据集上出现了微小的精度劣化。然而,当部分或完全局部化的ASTGNNs被重新初始化并在相同数据上重新训练时,精度会出现显著且一致的下降。基于这些观测结果,我们认为:(i)在测试数据中,空间依赖提供的信息主要包含在时序依赖提供的信息之中,因此在推理阶段基本可以被忽略;(ii)尽管空间依赖提供的是冗余信息,但它对于ASTGNNs的有效训练至关重要,因此在训练过程中不能被忽略。此外,ASTGNNs的局部化有望降低大规模时空数据所需的高昂计算开销,并进一步支撑ASTGNNs的分布式部署。

英文摘要:

Spatial-temporal graph models are prevailing for abstracting and modelling spatial and temporal dependencies. In this work, we ask the following question: whether and to what extent can we localise spatial-temporal graph models? We limit our scope to adaptive spatial-temporal graph neural networks (ASTGNNs), the state-of-the-art model architecture. Our approach to localisation involves sparsifying the spatial graph adjacency matrices. To this end, we propose Adaptive Graph Sparsification (AGS), a graph sparsification algorithm which successfully enables the localisation of ASTGNNs to an extreme extent (fully localisation). We apply AGS to two distinct ASTGNN architectures and nine spatial-temporal datasets. Intriguingly, we observe that spatial graphs in ASTGNNs can be sparsified by over 99.5\% without any decline in test accuracy. Furthermore, even when ASTGNNs are fully localised, becoming graph-less and purely temporal, we record no drop in accuracy for the majority of tested datasets, with only minor accuracy deterioration observed in the remaining datasets. However, when the partially or fully localised ASTGNNs are reinitialised and retrained on the same data, there is a considerable and consistent drop in accuracy. Based on these observations, we reckon that \textit{(i)} in the tested data, the information provided by the spatial dependencies is primarily included in the information provided by the temporal dependencies and, thus, can be essentially ignored for inference; and \textit{(ii)} although the spatial dependencies provide redundant information, it is vital for the effective training of ASTGNNs and thus cannot be ignored during training. Furthermore, the localisation of ASTGNNs holds the potential to reduce the heavy computation overhead required on large-scale spatial-temporal data and further enable the distributed deployment of ASTGNNs.

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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