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Help Desk Phone Support Simulation

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 a 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 BPSim. 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.

Example BPMN Business Process Simulation in Sparx Systems Enterprise Architect

  • 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
Chart showing time customers spend in different states based on a BPSim Simulation

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 BPSim can help.

BPSim Configuration

  1. Open the Configure BPSim window ('Simulate > Process Analysis > BPSim > Open BPSim Manager').
  2. Click on the icon and the Add New button, and create a Business Process Simulation Artifact named Pen & Paper Analysis 7 Customers.
  3. Click on the icon and browse for and select the Package containing the corresponding BPMN 2.0 model.
  4. Open the model diagram and click on the Resource element called 'Support'.
  5. In the 'Category' column on the window, click on the New Parameter drop-down arrow and select 'Resource', then click on the 'Parameter' drop-down arrow and select 'Quantity', and in the 'Values' field type '2'.
  6. Click on the icon.
    BPSim dialog for configuration of available resources in Enterprise Architect
  1. In the diagram, click on the 'Customer calls in' Start Event element.
  2. In the 'Category' column in the window click on the New Parameter drop-down arrow and select 'Control'.
  3. Click on the 'Parameter' drop-down arrow and select 'InterTriggerTimer'.
  4. In the 'Value' field, click on the Browse. button, select the 'Constant' tab and 'Numeric', type '2' in the 'Constant Numeric' field and select 'minutes' in the 'TimeUnit' field, then click on the OK button.
  5. Repeat steps 2 and 3, selecting 'TriggerCount' in the 'Parameter' field, then in the 'Value' field type '7'.
  6. Click on the icon.
  1. In the diagram, click on the 'Service Customer' Activity element.
  2. In the 'Category' column in the window click on the New Parameter drop-down arrow and select 'Time'.
  3. Click on the 'Parameter' drop-down arrow and select 'ProcessingTime'.
  4. In the 'Value' field, click on the Browse. button, select the 'Constant' tab and 'Numeric', type '10' in the 'Constant Numeric' field and select 'minutes' in the 'TimeUnit' field, then click on the OK button.
  5. In the 'Category' column in the window click on the New Parameter drop-down arrow and select 'Resource'.
  6. Click on the 'Parameter' drop-down arrow and select 'Selection'.
  7. In the 'Value' field, click on the Browse. button, select 'Support' (the name of the Resource element you created in the model) and click on the Add Selection by Resource(s) button to move 'Support' into the 'Resource or Role' column.
  8. In the 'Quantity Required' column type 1.
  9. Click on the OK button. In the 'Values' field the automatically-generated expression bpsim:getResource('Support',1) displays.
  10. Click on the icon.

Run the Simulation

  1. On the Configure BPSim window click on the 'Execute' tab and on the icon in the toolbar.
  2. When the simulation is complete, click on the icon to open the 'Configuration Summary' tab of the 'Results' tab'

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.

  1. Double-click on TwoSupport to open the Configure BPSim window; you can see that all the configurations are kept from the copied source
  2. In the diagram, click on the 'Customer calls in' Start Event element.
  3. In the 'Category' column in the window click on the 'Value' field for 'Control' - 'Trigger Count' and change the value to '20'.
  4. Click on the icon.

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

  1. Copy TwoSupport and press Ctrl+Shift+V to paste, giving the new element the name ThreeSupport.
  2. Double-click on ThreeSupport to open the 'Configure BPSim' dialog.
  3. In the diagram, click on the 'Support' Resource element.
  4. In the Configure BPSim window, in the 'Values' field for 'Resource' - 'Quantity', type '3'.
  1. Again, copy TwoSupport and press Ctrl+Shift+V to paste, giving this new element the name FiveSupport.
  2. Double-click on FiveSupport to open the 'Configure BPSim' dialog.
  3. In the diagram, click on the 'Support' Resource element.
  4. In the Configure BPSim window, in the 'Values' field for 'Resource' - 'Quantity', type '5'.

Run the simulations and do a comparison; in the Browser window:

  1. Ctrl+click on TwoSupport, ThreeSupport and FiveSupport, then right-click and select the 'Show BPSim Configuration' option.
  2. Ctrl+click on TwoSupport-Result, ThreeSupport-Result and FiveSupport-Result, then right-click and select the 'Show BPSim Report' option.

Tips:

  • Click on the button and 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 for 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. Try copying one of the Business Process Simulation Artifacts and configure and run a simulation for 4 Support resources.

Show Result with Chart

  1. Drag a 'BPSim Result Chart' icon from the Toolbox onto the diagram and create a BPSim Result Chart Artifact; call it Average Waiting Time.
  2. Right-click on the Artifact and select the 'Properties' option to display the element 'Properties' dialog; click on the 'BPSim Chart' page.
  3. Click on the Browse. button and select a Base Report from which to define the schema (legends) to use in the chart; select TwoSupport-Result.
  4. Choose the schema 'Time' | 'Service Customer' | 'Average Time Waiting For Resource'.
  5. Click on the Add button to add another two BPSim Reports: ThreeSupport-Result and FiveSupport-Result
  6. Click on the OK button and adjust the size of the Chart element; this Chart gave us very straightforward information

Business Process Simulation Results Chart in Sparx Systems Enterprise Architect

  1. Create another BPSim Result Chart Artifact on the diagram, called Utilisation Rate.
  2. Double-click on the Artifact to display the element 'Properties' dialog and click on the 'BPSim Chart' tab.
  3. Click on the Browse. button and select a Base Report from which to define the schema (legends) to use in the Chart; select TwoSupport-Result.
  4. Choose the schema 'Resource' | 'Support' | 'Degree Of Utilisation'.
  5. Click on the Add button to add another two BPSim Reports: ThreeSupport-Result and FiveSupport-Result.
  6. Click on the OK button and adjust the size of the Chart element.

Business Process Simulation Results Chart in Sparx Systems Enterprise Architect