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SAS/OR: The QSIM Application

Getting Started

The QSIM Application is a SAS application for modeling and analyzing queueing systems using discrete event simulation. These models are used in a wide variety of scenarios that might be encountered in network and telecommunications systems, manufacturing systems, and transportation networks. For example, before instituting a re-engineered business process, you could use the QSIM Application to model the new process and study the model behavior to gain insight into how the new process might behave.

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Figure 1.1: An M/M/1 Queueing Model

The application has a graphical user interface that requires no programming and provides all the tools for building, executing, and analyzing discrete event simulation models.

Figure 1.1 shows a simple M/M/1 queueing model built with the QSIM Application. An M/M/1 queueing model has a Poisson arrival process, exponential service times for a single server, and a FIFO queueing discipline. You can build a model of such a queueing system, control the simulation of the model, and produce summary statistics from the simulation sample path from within the application. You can save the model and the sample path in SAS data sets for reuse and further analysis. The application is designed to simplify model building by encouraging the construction of hierarchical models based on user built model components that can be stored, shared, and replicated easily.

In this context a model is a directed network. Transactions flow through the network changing the state of the model upon arrival at vertices or nodes. The type of state change that occurs depends on the current state of the simulation and the particulars of the model.


Invoking the QSIM Application

User Interface

A Simple M/M/1 Queueing Model

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