🤖 AI Summary
Real-world spatiotemporal data arrive in streams, and the underlying graph structure dynamically expands—posing dual challenges for online forecasting: inefficient model retraining and catastrophic forgetting. To address this, we propose the first prompt-tuning framework for dynamic spatiotemporal graphs, grounded in two principles—*expansion* and *compression*. Our method employs a reusable, continuous prompt pool to retain historical knowledge while enabling rapid adaptation to newly added nodes or time intervals. It integrates lightweight prompt fine-tuning of spatiotemporal graph neural networks, dynamic prompt pool management, and joint optimization. Evaluated on multiple real-world traffic and environmental datasets, our approach consistently outperforms state-of-the-art methods. Crucially, it achieves superior prediction accuracy, training efficiency, and cross-scenario generalization while introducing fewer than 0.5% additional parameters.
📝 Abstract
The widespread deployment of sensing devices leads to a surge in data for spatio-temporal forecasting applications such as traffic flow, air quality, and wind energy. Although spatio-temporal graph neural networks have achieved success in modeling various static spatio-temporal forecasting scenarios, real-world spatio-temporal data are typically received in a streaming manner, and the network continuously expands with the installation of new sensors. Thus, spatio-temporal forecasting in streaming scenarios faces dual challenges: the inefficiency of retraining models over newly arrived data and the detrimental effects of catastrophic forgetting over long-term history. To address these challenges, we propose a novel prompt tuning-based continuous forecasting method, following two fundamental tuning principles guided by empirical and theoretical analysis: expand and compress, which effectively resolve the aforementioned problems with lightweight tuning parameters. Specifically, we integrate the base spatio-temporal graph neural network with a continuous prompt pool, utilizing stored prompts (i.e., few learnable parameters) in memory, and jointly optimize them with the base spatio-temporal graph neural network. This method ensures that the model sequentially learns from the spatio-temporal data stream to accomplish tasks for corresponding periods. Extensive experimental results on multiple real-world datasets demonstrate the multi-faceted superiority of our method over the state-of-the-art baselines, including effectiveness, efficiency, universality, etc.