Why Regularized Auto-Encoders learn Sparse Representation?
This addresses a problem for deep learning practitioners by offering an incremental improvement over Batch Normalization for training efficiency and flexibility.
The paper tackles the drawbacks of Batch Normalization, such as dependency on batch statistics and incompatibility with batch-size 1, by proposing Normalization Propagation, a non-adaptive technique that uses data-independent parametric estimates to remove covariate shift, resulting in computational speed improvements compared to BN.
While the authors of Batch Normalization (BN) identify and address an important problem involved in training deep networks-- \textit{Internal Covariate Shift}-- the current solution has certain drawbacks. For instance, BN depends on batch statistics for layerwise input normalization during training which makes the estimates of mean and standard deviation of input (distribution) to hidden layers inaccurate due to shifting parameter values (especially during initial training epochs). Another fundamental problem with BN is that it cannot be used with batch-size $ 1 $ during training. We address these drawbacks of BN by proposing a non-adaptive normalization technique for removing covariate shift, that we call \textit{Normalization Propagation}. Our approach does not depend on batch statistics, but rather uses a data-independent parametric estimate of mean and standard-deviation in every layer thus being computationally faster compared with BN. We exploit the observation that the pre-activation before Rectified Linear Units follow Gaussian distribution in deep networks, and that once the first and second order statistics of any given dataset are normalized, we can forward propagate this normalization without the need for recalculating the approximate statistics for hidden layers.