The Architecture Design and Assessment System (ADAS) was a set of software programs offered by the Research Triangle Institute from the mid-1980s until the early 1990s. A petri net-like graph model of a system was graphically created. The hierarchical graphs were simulated to determine resource utilization and throughput. Functional simulation of the model could be realized by attaching C or Ada code to the nodes. This enabled dynamic resource assignment, timing, and priority.