6. Adding Service Time Profiles for each process

Specify the time it takes to do a process by specifying a Service Time Profile.

2 Add a Service Time Profile called Take_Res_Details, and then click Define to open its full definition.

We want to simulate the real-world behavior of how long it takes to answer a call for a Reservation and take the Reservation Details. We determine that some calls can be very short in duration – taking a minimum of .5 minutes. Some can be as long as 6 minutes. For the most part, a call lasts one minute. We simulate this using a Triangular distribution.

3 Open the definition of the Take_Res_Details service time profile. Specify a Value Type of Distribution, and then click the Distribution button.

Note Ignore the other property fields for Constant and Variable. If you specify a Value Type of Distribution, only the value in the Distribution property will be taken into account during the simulation.

4 Within the Distribution Wizard dialog, specify a Minimum of .5 time units, a Mode of 1 time unit, and a Maximum of 6 time units. Click the Preview button to view the distribution.

We are specifying that a phone call to take reservation details can take a minimum of .5 minutes, a maximum of 6 time units, and on average takes 1 time unit. If we had chosen a distribution such as Negative Exponential, there would be possibility that the phone call could last infinite minutes, which might be possible but we will not model that in our hotel system.

You can play around with the distributions, previewing each one, if you want to set a different probability distribution for the Service Time Profile.

6 Back in the Definition dialog for the Time Profile, observe that there is a Multiplier property (see description below).

Multiplier presents a quick and dirty way to vary the time it takes to perform the process, without having to change the Distribution profile. When simulating the diagram to see how it behaves, you can multiply the time it takes to do the process, setting it over 100 percent to increase the time; setting it under 100 percent to decrease the time.