MMAE-ECG: multi-scale masked autoencoder for ECG anomaly detection

Summary

1. Multi-scale masking. Two token streams are built from the same signal: - global stream 𝒰 = all 40 segments; - local stream 𝒱w = a contiguous window of δ=4 segments (1.0 s) starting at one of 9 fixed offsets {1,5,9,...,33}, boundary segments excluded.