A tutorial on UniFit: a system for total support of simulation input modeling

The UniFit II software package is used to select simulation input probability distributions. The original UniFit software package offered state-of-the-art support for selection of distributions. UniFit II provides more comprehensive and easier-to-use support. UniFit II allows one to determine easily which of the standard probability distributions (e.g. exponential, gamma, normal, etc.) best represents a set of observations. The package helps to determine the quality of the correspondence between the selected probability distribution and the observations. In most cases the correspondence will be good enough for simulation purposes, and UniFit II specifies how to generate values from the selected distribution in any of the major simulation packages. In the situation where the correspondence is not good, UniFit reports how to generate values directly from the observed data. UniFit II supports two methods for choosing distributions when data are not available. The first has been commonly recommended for this no-data case and may be used in almost any context. The second has been developed for specifying the distributions of operating and repair time random variables needed for simulations of manufacturing systems