confused about where the hybrid network minimizing the number of identity connection

[edenzt]

hi, I'm confused about the hybrid network. In this paper, it said that the hybrid network combines the Hourglass and U-Net architectures. The newly proposed architecture minimizes the number of identity connections within the network. I just find that the author change the feature fusion in the hourglass skip connection from element-wise summation to concatenation(as U-Net). Where does the number of identity connection decreasing? Thank you~