Deep Belief Network
Deep Belief Network
A **Deep Belief Network (DBN)** is a multi-layer generative graphical model. DBNs have bi-directional connections ([RBM](https://paperswithcode.com/method/restricted-boltzmann-machine)-type connections) on the top layer while the bottom layers only have top-down connections. They are trained using layerwise pre-training. Pre-training occurs by training the network component by component bottom up: treating the first two layers as an RBM and training, then treating the second layer and third layer as another RBM and training for those parameters.

Source: [Origins of Deep Learning](https://arxiv.org/pdf/1702.07800.pdf)

Image Source: [Wikipedia](https://en.wikipedia.org/wiki/Deep_belief_network)