Towards Spatio-Temporal Aware Traffic Time Series Forecasting--Full Version
This work addresses the challenge of complex spatio-temporal dynamics in traffic forecasting for urban planning and management, representing an incremental improvement by enhancing existing attention-based models with spatio-temporal awareness.
The paper tackles the problem of traffic time series forecasting by addressing the limitations of spatio-temporal agnostic models, which assume uniform patterns across locations and time, leading to sub-optimal results. The proposed framework encodes time series into stochastic variables to generate location-specific and time-varying parameters, and with a novel window attention scheme, it achieves improved accuracy and efficiency, outperforming state-of-the-art methods on four datasets.
Traffic time series forecasting is challenging due to complex spatio-temporal dynamics time series from different locations often have distinct patterns; and for the same time series, patterns may vary across time, where, for example, there exist certain periods across a day showing stronger temporal correlations. Although recent forecasting models, in particular deep learning based models, show promising results, they suffer from being spatio-temporal agnostic. Such spatio-temporal agnostic models employ a shared parameter space irrespective of the time series locations and the time periods and they assume that the temporal patterns are similar across locations and do not evolve across time, which may not always hold, thus leading to sub-optimal results. In this work, we propose a framework that aims at turning spatio-temporal agnostic models to spatio-temporal aware models. To do so, we encode time series from different locations into stochastic variables, from which we generate location-specific and time-varying model parameters to better capture the spatio-temporal dynamics. We show how to integrate the framework with canonical attentions to enable spatio-temporal aware attentions. Next, to compensate for the additional overhead introduced by the spatio-temporal aware model parameter generation process, we propose a novel window attention scheme, which helps reduce the complexity from quadratic to linear, making spatio-temporal aware attentions also have competitive efficiency. We show strong empirical evidence on four traffic time series datasets, where the proposed spatio-temporal aware attentions outperform state-of-the-art methods in term of accuracy and efficiency. This is an extended version of "Towards Spatio-Temporal Aware Traffic Time Series Forecasting", to appear in ICDE 2022 [1], including additional experimental results.