For me is usefull to resolve parallel task execution and network availability/minimal performance problems, using critical path method (CPM) and PERT, according of the context, I translate the variables “employed”, “item”,”event”… by resources like bandwidth needs, computing cost, and the different kind of “time” by aproximations values of process complexity , medium time desired, or others variables which limit or condition the problem.
The best thing of all, it is very easy to optimization expressing the graph as a matrix, and after applying, the critical path algorithm for obtain all possibles parallels tasks and their executions orders.

PERT/CPM example, http://www.springer.com/cda/content/document/cda_downloaddocument/9783642251740-c1.pdf

CPM http://en.wikipedia.org/wiki/Critical_path_method

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