Help Desk Phone Support Simulation - Resource Perspective

In this example, we create a very simple model to simulate a Help Desk phone support process.

We set up a scenario in which resources are limited and the requests have to be put in a waiting queue for a resource. Then we try to seek a balance point between customer's waiting time and the number of resources, using a what-if analysis.

Firstly, we model this process step-by-step, starting with a simple parameter setting than can be calculated with pen and paper, then verifying it with EABPSim. After that, we perform a what-if analysis that might help the manager to make a decision.

Create BPMN Model

The model itself is very simple, consisting of a Start Event, a Task and an End Event.

Create a Start Event called Customer calls in
Add a Sequence Flow to a target Abstract Task called Service Customer
Add a Sequence Flow to a target End Event called Customer hangs up

Create a BPMN2.0 Resource named Support; this element will be used in the BPSim Configuration.

Pen and Paper Analysis

We will use pen and paper to analyze this case:

7 customers call in at 2 minute intervals
2 support resources are available
Each service will take 10 minutes

Seen from this result, it is already a very complicated computation for such a simple model when resource constraints are applied. When the process expands and more constraints are applied, analyzing the process with pen and paper will quickly become impossible. We will demonstrate how EABPSim can help.

BPSim Configuration

Open the Configure BPSim window ('Simulate > BPMN/BPSim > Manage > Open BPSim Manager')
Create a Business Process Simulation Artifact named Pen & Paper Analysis 7 Customers
Select the Package containing the corresponding BPMN 2.0 model

All the BPMN elements will be loaded in to the Configure BPSim window.

In the left-hand tree on the window, expand the 'Resource' group and click on Support; click on the 'Resource' tab and on the drop-down arrow of the 'New Parameter' field, then select 'Quantity' and, in the 'Value' field, type '2'

In the left-hand tree, expand the 'StartEvent' group, then click on Customer calls in and on the 'Control' tab
Click on the drop-down arrow of the 'New Parameter' field and select, in turn:
     - 'InterTriggerTimer' and, in the 'Value' field, click on the button, select the 'Constant' tab
        and 'Numeric', type '2' in the 'Constant Numeric' field and select 'minutes' in the 'TimeUnit' field
     - 'TriggerCount', and in the 'Value' field type '7'

In the left-hand tree, expand the 'Activity' group, then click on Service Customer and on the 'Time' tab
Click on the drop-down arrow of the 'New Parameter' field and select 'ProcessingTime' and, in the 'Value' field, click on the button and select the 'Constant' tab and 'Numeric', type '10' in the 'Constant Numeric' field and select 'minutes' in the 'TimeUnit' field
Click on the 'ResourceRole' tab, click on the Add Resource Role button; in the new row in the 'Resource Roles defined in BPMN' panel, click on the button in the 'BPMN Resource' field and select the Support element you created earlier
In the 'Quantity' field, type '1'

In the 'Resource Selection Expression for Activity' panel the automatically generated expression bpsim:getResource('Support',1) displays.

Run the Simulation

On the Configure BPSim window Toolbar, click on the Run button; the 'BPSim Simulation Controller' dialog displays
Click on the Run button drop-down arrow and select 'Standard Simulation'
When the simulation is complete, click on the button on the 'BPSim Simulation Controller' dialog toolbar to open the 'BPMN Simulation Report View'

Tip: You can select the 'Show Only Non-Empty Items' option to filter the results.

The results match the pen and paper analysis.

Simulation - 2 Support Resources for 20 customers

You can create a new Business Process Simulation Artifact by copying an existing BPSim Configuration. Copy the Pen & Paper Analysis 7 customers element and press Ctrl+Shift+V to paste, giving the new element the name TwoSupport.

Double-click on TwoSupport to open the 'Configure BPSim' dialog; you can see that all the configurations are kept from the copied source
Expand the 'StartEvent' group and click on Customer calls in; click on the 'Control' tab and, in the 'Value' field for the 'TriggerCount' parameter, change the figure to '20'

Run simulation and analyze results

From the report, you can see that:

The 'Average Time Waiting For Resource' is 27 minutes and the 'Maximum Time Waiting For Resource' is 54 minutes

The two Support resources - are they busy? If they were not, we might have to change the process to use all of their time and reduce the customer's waiting time; however, the 'Degree Of Utilisation' is at 98%, which indicates that the resources had almost no idle time

'What-If' I have more staff? Compare 2 Support Resources with 3 and 5 Support Resources

Copy TwoSupport and press Ctrl+Shift+V to paste, giving the new element the name ThreeSupport
Double-click on ThreeSupport to open the 'Configure BPSim' dialog, expand the 'Resource' group and click on Support, then click on the 'Resource' tab and, for the 'Quantity' parameter, change the 'Value' field to '3'

Copy TwoSupport and press Ctrl+Shift+V to paste, giving the new element the name FiveSupport
Double-click on FiveSupport to open the 'Configure BPSim' dialog, expand the 'Resource' group and click on Support, then click on the 'Resource' tab and, for the 'Quantity' parameter, change the 'Value' field to '5'

Run the simulations and do a comparison; in the Project Browser:
     - Ctrl+click on TwoSupport, ThreeSupport and FiveSupport, then right-click and select the 'Show
        BPSim Configuration' option
     - Ctrl+click on TwoSupport-Result, ThreeSupport-Result and FiveSupport-Result, then right-click
        and select the 'Show BPSim Report' option

Tips:

Use the button and click on the 'Show only different items' option for both views
You can dock the views together, so they provide direct comparisons: THESE are the differences in results caused by THOSE differences in configuration
Toggle the filter bar to filter the items that interest you

Analysis

The docked comparison views show the configuration differences and the corresponding result differences.

The customer's waiting time dropped from 27 minutes (2 Support resources) to 11.4 minutes (3 Support resources) and further down to 0 minutes (5 Support resources)
The 'Degree Of Utilisation' dropped from 98% (2 Support resources) to 93% (3 Support resources) and further down to 83% (5 Support resources)

The customers will most likely be satisfied with 5 Support resources; however, the cost might be out of budget. So 3 or possibly 4 Support resources might be a balance point for this case. You are recommended to copy one of the Business Process Simulation Artifacts and configure and run a simulation for 4 Support resources.

Show Result with Chart

Drag a 'BPSim Result Chart' icon from the Toolbox onto the diagram and create a BPSim Result Chart Artifact; call it Average Waiting Time

Double-click on the Artifact to display the element 'Properties' dialog and click on the 'BPSim Chart' tab

Click on the button and select a Base Report from which to define the schema (legends) to use in the chart; select TwoSupport-Result

Choose the schema 'Time' | 'Service Customer' | 'Average Time Waiting For Resource'

Click on the Add button to add another two BPSim Reports: ThreeSupport-Result and FiveSupport-Result

Click on the OK button and adjust the size of the chart element; this chart gave us very straightforward information

Create another BPSim Result Chart Artifact on the diagram, called Utilisation Rate

Double-click on the Artifact to display the element 'Properties' dialog and click on the 'BPSim Chart' tab

Click on the button and select a Base Report from which to define the schema (legends) to use in the chart; select TwoSupport-Result

Choose the schema 'Resource' | 'Support' | 'Degree Of Utilisation'

Click on the Add button to add another two BPSim Reports: ThreeSupport-Result and FiveSupport-Result

Click on the OK button and adjust the size of the chart element