More recently, researchers have investigated joint inference techniques for event extraction using Markov Logic Networks (MLNs) (e.g., Poon and Domingos (2007), Poon and Vanderwende (2010), Riedel and McCallum (2011a)), a statistical relational model that enables us to model the dependencies between different instances of a data sample.
it is extremely challenging to make joint inference using MLNs work well in practice (Poon and Domingos, 2007).