Fig. 1. Original signal of tapping and the decomposition result. (a) Original signal; (b) decomposition result

Fig. 2. Original fiber intrusion signal and preprocessing results. (a) Original signal; (b) preprocessing result

Fig. 3. Flowchart of the AdaBoost algorithm

Fig. 4. Validation curves of GBDT algorithm under different parameters. (a) n_estimators; (b) learning_rate; (c) max_depth; (d) subsample

Fig. 5. AdaBoost algorithm grid search validation curve. (a) n_estimators; (b) learning_rate

Fig. 6. Grid search verification curve of the SVM algorithm. (a) C; (b) gamma

Fig. 7. Confusion matrices for different algorithms. (a) GBDT algorithm; (b) DT-AdaBoost algorithm; (c) SVM algorithm

Fig. 8. Recognition rate of fiber intrusion signals for different algorithms