PSI - Issue 77

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Hugo Mesquita Vasconcelos et al. / Procedia Structural Integrity 77 (2026) 601–610 Hugo Mesquita Vasconcelos/ Structural Integrity Procedia 00 (2026) 000–000

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Two-stage CM

Traditional CM

Fig. 3. (a) Traditional training confusion matrix; (b) two-stage training confusion matrix.

3.3. Full MHC Approach The full hierarchical configuration introduced the three heads—pre- operational (α), primary (θ), and concrete (β) — progressively throughout training. Validation accuracy and F1-scores peaked around epoch 16, reaching maximum values earlier than in the two-stage configuration, while validation loss reached its minimum at the first epoch and remained stable throughout training. The mean epoch duration was 821 seconds and training took 9.4 hours. The final model was the 16 th epoch. The Full MHC training approach achieved high and consistent performance across major vessel categories. The background class-maintained precision and recall values above 0.96 and 0.92, respectively. Cargo, dredger, tug, and passenger ship classes presented F1-scores between 0.62 and 0.74, with the dredger and cargo categories showing the

Full-MHC CM

Fig. 4. Full MHC training confusion matrix.

most stable results across training epochs. The fishing category obtained moderate precision but limited recall, while