Modeling of interdependent infrastructures

An actor-based modeling methodology is used to simulate interactions among interdependent commercial infrastructures. The goal of this method is to capture the complex, nonlinear, self-organizing, emergent, and sometimes chaotic behaviors and interactions exemplified by complex systems, rather than relying on traditional aggregate mathematical and simulation techniques. A prototype model of four interdependent infrastructures was considered as an example. The actor-based definitions of the electric-power transmission line and natural-gas pipeline networks were developed to realistically simulate the dynamic interactions within each of these infrastructures and the interactions and interdependencies between these two infrastructures. A three-dimensional representation of system components and interconnectivity was developed. The visualization is an interactive, three-dimensional, geographically based, "layered" view of infrastructure interdependencies. It also links to a geographic information system for data analysis. A unique iterative natural-gas network solver algorithm was developed. Our assessment shows that a hybrid approach using an actor-based definition of infrastructure components in conjunction with iterative and commercial solvers has great promise for addressing the operation of interdependent infrastructures in a restructured and deregulated environment.