You cannot just assign a role to a process – to do so, would mean that the role is working on that process at all times, 24 hours a day.
To reflect what happens in the real world, we specify two things – Resource Allocation and Resource Availability. Resource Allocation specifies how many resources (or roles) are needed to do a job. Resource Availability specifies how many resources are available at any one time to do a job. For example, let us say you need two people to move a table in your house. The resource allocation is two people. If one person is available (a resource availability of 1), you cannot move the table. You need two people (resource availability of 2).
In this tutorial, we have created roles, which reflect the people who do the work. We have created work shifts. Now we must specify exactly how available those roles are during the shifts to do the work. Is a person available for the whole day, for five hours during the day, do they work extra time?
We create something called a Resource Availability definition that specifies the availability of a role. A Resource Availability definition specifies a role available for a work shift, how many roles of a certain type are available for a shift, and any time that those roles might work past a shift.
Let us create the following Resource Availability definition:
1 Within System Architect’s Explorer, highlight the Definitions branch and select New.
2 In the ‘Select new type for all Methods’ dialog, scroll down and double-click the Resource Availability definition.
3 Enter Orders Manager During Week as the name of the Resource Availability.
4 Under the Shift property box, select the Choices button. The Select and Drag dialog opens to reveal the Shifts that are available. Select and drag in the 9 to 5 Working Week as the Shift.
5 For the Role property box, select the Choices button to reveal the Roles that are available. Select the Orders Manager as the Role.
6 Leave the default setting of 1 for the Quantity on Shift. This specifies that one Orders Manager is available during the working day, every day during the week (which is what the 9 to 5 Working Week shift specifies in its definition).
7 Set the Allowances to 20 Minutes. This will allow the Orders Manager to work 20 minutes past their shift to finish their work.
Your Resource Availability should resemble the one below:
8 Press the OK button to accept the definitions and close the dialog.
9 Create two more Resource Availabilities called Order Clerk 1 Working Week and Order Clerk 2 Working Week. For each one leave the default setting for Quantity on Shift and set the following properties:
Resource Availability
Shift
Role
Quantity On Shift
Allowance
Order Clerk 1 Working Week
9 to 5 Working Week
Order Clerk 1
1
10 Minutes
Order Clerk 2 Working Week
9 to 5 Working Week
Order Clerk 2
1
10 Minutes
Note The Resource Availability definition may be thought of as a hidden definition in the process modeling scheme of things. You do not get at it directly from the Role definition, Shift definition, or Process definition. Yet it is important information that must be specified to relate if and when resources are available. If you fail to specify Resource Availability definitions, your simulation will report bottlenecks from the start, since no resources have been specified as being available.
