This method minimizes the loss reconstruction error for in-domain inputs, and does not require any labelled data.
This method exploits the high correlation in the convolutions in ResNet-like architectures by the use of product quantization (PQ). The approach here focuses on reconstructing the activations, and not the weights. This results in better in-domain reconstruction, and does not require any supervision.
Vector Quantization (VQ) and Product Quantization (PQ) decompose the high-dimensional space into a cartesian product of subspaces that are quantized separately. These are typically studied under the context of nearest neighbour search.