🤖 AI Summary
To address the challenges of modeling dynamic cross-client spatial dependencies and balancing privacy with predictive performance in traffic flow forecasting under federated learning, this paper proposes FedSTGD—a novel federated spatio-temporal graph learning framework. FedSTGD is the first to explicitly model dynamic spatial dependencies in a federated setting. It introduces a nonlinear graph computation decomposition mechanism and a node embedding enhancement module to decouple complex graph operations and strengthen local representation capability. Additionally, it establishes a lightweight server–client coordination protocol to enable efficient distributed spatio-temporal graph learning. Extensive experiments on four real-world traffic datasets demonstrate that FedSTGD consistently outperforms existing state-of-the-art methods in RMSE, MAE, and MAPE, achieving performance close to centralized training. Ablation studies validate the effectiveness of each component, while hyperparameter analysis confirms strong robustness.
📝 Abstract
Spatio-temporal graphs are powerful tools for modeling complex dependencies in traffic time series. However, the distributed nature of real-world traffic data across multiple stakeholders poses significant challenges in modeling and reconstructing inter-client spatial dependencies while adhering to data locality constraints. Existing methods primarily address static dependencies, overlooking their dynamic nature and resulting in suboptimal performance. In response, we propose Federated Spatio-Temporal Graph with Dynamic Inter-Client Dependencies (FedSTGD), a framework designed to model and reconstruct dynamic inter-client spatial dependencies in federated learning. FedSTGD incorporates a federated nonlinear computation decomposition module to approximate complex graph operations. This is complemented by a graph node embedding augmentation module, which alleviates performance degradation arising from the decomposition. These modules are coordinated through a client-server collective learning protocol, which decomposes dynamic inter-client spatial dependency learning tasks into lightweight, parallelizable subtasks. Extensive experiments on four real-world datasets demonstrate that FedSTGD achieves superior performance over state-of-the-art baselines in terms of RMSE, MAE, and MAPE, approaching that of centralized baselines. Ablation studies confirm the contribution of each module in addressing dynamic inter-client spatial dependencies, while sensitivity analysis highlights the robustness of FedSTGD to variations in hyperparameters.