A multi-task transformer-based prediction model for HIAF detector operation sequences
摘要
Beam tuning at the high-intensity heavy-ion accelerator facility (HIAF) remains heavily reliant on operator experience. This study proposes a multi-task Transformer ensemble method to predict detector operation sequences and provide real-time recommendations for the next operation during beam tuning, with the aim of supporting future automated operation and maintenance.
MethodsBit-level state-change detection of HIAF machine protection system (MPS) programmable logic controller (PLC) data yielded 2108 operation events spanning ten patterns, which were validated by unsupervised clustering. A multi-task Transformer with 247-dimensional multi-level features jointly predicts the next device, device type, location region, operation pattern, and anomaly status. Rare-class merging, embedding-layer Mixup, and a weighted Transformer ensemble were employed to mitigate data sparsity, class imbalance, and overfitting, and sequence-wise grouped cross-validation was used to prevent sliding-window leakage.
ResultsUsing sequence-wise grouped fivefold cross-validation, in which all sliding-window samples generated from the same original operation sequence were assigned to the same fold, the deployed seven-model Mixup ensemble achieved Top-5 accuracy of 82.3% ± 1.9%, Top-1 accuracy of 53.7% ± 2.4%, and anomaly-detection AUC of 87.8% ± 6.4%.
ConclusionThe proposed method has been deployed as a stateful incremental prediction API, providing a practical basis for real-time HIAF beam-tuning assistance and future automated operation and maintenance.