UniFit II: Total support for simulation input modeling

The role of simulation input modeling in a successful simulation study is explained. Two pitfalls in simulation input modeling are then presented, and it is explained how analysts, regardless of their knowledge of statistics, can easily avoid these pitfalls through the use of UniFit II. A set of real-world system data is used to demonstrate how the package automatically specifies, evaluates, and ranks candidate probability distributions, and then assists an analyst in deciding whether the best candidate probability distribution provides an adequate representation of the data. If no candidate probability distribution provides an adequate fit, then UniFit II can define an empirical distribution function. In either case, the probability model can be automatically expressed in the analyst´s simulation software. The authors consider the general case of selecting a probability distribution in the absence of data. As an example, they show how UniFit II can be used to create busy-time and downtime models for machines that are subject to random breakdowns