tk/>GMTk</a>, which is
an excellent C++ package for DBNs.


<h1><a name="spec">Model specification</h1>


<!--<h1><a name="dbn_intro">Dynamic Bayesian Networks (DBNs)</h1>-->

Dynamic Bayesian Networks (DBNs) are directed graphical models of stochastic
processes.
They generalise <a href="#hmm">hidden Markov models (HMMs)</a>
and <a href="#lds">linear dynamical systems (LDSs)</a>
by representing the hidden (and observed) state in terms of state
variables, which can have complex interdependencies.
The graphic