Vertical federated learning (VFL) is utilized for time series forecasting in areas like healthcare and manufacturing.
Challenges include data privacy and overfitting on small, noisy datasets.
A novel framework called "Secret-shared Time Series Forecasting with VFL" (STV) is proposed to address these challenges.
STV features privacy-preserving algorithms for forecasting with SARIMAX and autoregressive trees on vertically-partitioned data.
Decentralized forecasting is achieved through secret sharing and multi-party computation in STV.
N-party algorithms for matrix multiplication and inverse operations aid in parameter optimization, ensuring strong convergence with minimal tuning complexity.
STV's performance is evaluated on six datasets from various contexts, showing comparable forecasting accuracy to centralized approaches.
STV's exact optimization surpasses centralized methods by 23.81% in forecasting accuracy, including state-of-the-art models like long short-term memory.
The scalability of STV is assessed by comparing communication costs of exact and iterative optimization.
The code and supplementary material for STV are accessible online at https://github.com/adis98/STV.