W1 and W7, W2 and W9, and W3 and W11 were located in the same depth of the sand layer, respectively. The W1 and W7 nodes were near the surface, W2 and W9 were located in the middle of the sand layer, and W3 and W11 were the bottom nodes of the sand layer. The time–history ...
3. Feature Construction and Extraction As can be seen from Figure 2, with the increase of compression times, the AAC audio scale factor will be relatively reduced. With this property, the difference between the audio recompressed audio and the original audio scale factor is used as a feature ...