Modeling Short-Term Energy Load with Continuous Conditional Random Fields

摘要

Short-term energy load forecasting, such as hourly predictions for the next n (n ≥ 2) hours, will benefit from exploiting the relationships among the n estimated outputs. This paper treats such multi-steps ahead regression task as a sequence labeling (regression) problem, and adopts a Continuous Conditional Random Fields (CCRF) strategy. This discriminative approach intuitively integrates two layers: the first layer aims at the prior knowledge for the multiple outputs, and the second layer employs edge potential features to implicitly model the interplays of the n interconnected outputs. Consequently, the proposed CCRF makes predictions not only basing on observed features, but also considering the estimated values of related outputs, thus improving the overall predictive accuracy. In particular, we boost the CCRF's predictive performance with a multi-target function as its edge feature. These functions convert the relationship of related outputs with continuous values into a set of "sub-relationships", each providing more specific feature constraints for the interplays of the related outputs. We applied the proposed approach to two real-world energy load prediction systems: one for electricity demand and another for gas usage. Our experimental results show that the proposed strategy can meaningfully reduce the predictive error for the two systems, in terms of mean absolute percentage error and root mean square error, when compared with three benchmarking methods. Promisingly, the relative error reduction achieved by our CCRF model was up to 50%.