1. A computer implemented method for structure evaluation of time-dependent acyclic graphs comprising: determining a validity of one or more nodes of an acyclic graph structure by comparing an identified validity period to the nodes of the graph structure, each of at least a subset of the nodes associated with a particular time period; and generating a validity graph for the validity period including one or more of the nodes of the graph structure that are valid for the identified validity period based on the respective time period.