Belief Nets

• A belief net is a directed acyclic graph composed of stochastic variables. • We get to observe some of the variables and we would like to solve two problems: • The inference problem: Infer the states of the unobserved variables. • The learning problem: Adjust the interactions between variables to make the network more likely to generate the observed data.

stochastic hidden cause

visible effect

We will use nets composed of layers of stochastic binary variables with weighted connections