Resource graphs for modeling large-scale, highly congested systems

Simulations often execute too slowly to be effective tools for decision-making. In particular, this problem has been found in semiconductor manufacturing where conventional job-driven simulation models explicitly track each lot of wafers as it progresses through the system. While a job-driven simulation model offers some advantages, they inherently execute slowly. This paper explicitly defines resource-driven modeling. Here jobs are implicitly tracked through their resource usage. Resource-driven simulations typically run much faster than job-driven simulations. This speed-up is insensitive to congestion and is most dramatic when the system is highly congested and therefore most interesting to the analyst. There can also be a significant reduction in memory footprint. However, there is a potential tradeoff in information loss