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Calendar-Based Help Desk Phone Support Simulation

In this example, we create a very simple model to simulate a Help Desk telephone support process, based on calendar settings. We assume that:

  • Customers call in at different intervals on weekdays and weekends
  • Processing times differ between weekdays and weekends
  • There are different numbers of support resources on weekdays and weekends

We model this process step by step, then create calendars and configure the Business Process simulation, which is simple enough to be calculated with pen and paper. After that, we run the simulation to compare that result with the pen and paper analysis.

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

  1. Create a Start Event Customer calls in.
  2. Add a Sequence Flow to the target abstract task Activity Service Customer.
  3. Add a Sequence Flow to the target End Event Customer hangs up.
  4. Create a BPMN2.0 Resource named Support.
  5. Create a BPMN2.0::ResourceRole inside Service Customer, give it the name support and set the tag resourceRef to the name of the Resource element Support.

Pen and Paper Analysis

We can use pen and paper to analyze this case:

  • The simulation duration is 2 hours and 10 minutes, from 8:00AM to 10:10AM
  • A customer calls in every 20 minutes on weekdays
  • A customer calls in every 60 minutes on weekends
  • To service each customer takes 50 minutes on weekdays
  • To service each customer takes 40 minutes on weekends
  • There are 2 support resources on weekdays
  • There is 1 support resource on weekends

Looking at this result, when resource constraints are applied the computation is quite complicated for such a simple model.

On weekdays

  • 7 customers called at intervals of 20 minutes over a duration of 2 hours and 10 minutes
  • 4 customer calls were terminated normally
  • 2 customer calls were interrupted because of timeout
  • 1 customer call was not answered
  • Support1 worked continuously for 130 minutes, Support2 worked continuously for 110 minutes

On weekends

  • 3 customers called at intervals of 60 minutes over a duration of 2 hours and 10 minutes
  • 2 customer calls were terminated normally
  • 1 customer call was interrupted because of timeout
  • Support1 worked 90 minutes, in 40-minute blocks with an interval of 20 minutes between calls

Now we will see how BPSim can help.

BPSim Configuration

In this section, we first create the Calendars, then we set up the Duration and Start parameters.

For element parameters, you can specify one or more calendars for a given parameter. However, if any calendar is set for a parameter value, a default value (without any calendar specified) must exist, otherwise the simulation will not work.

Clicking on the button on the Configure BPSim window toolbar will automatically check this constraint for you.

Task

Action

Create BPSim Artifact and Set Package

  1. Open the Configure BPSim window ('Simulate > Process Analysis > BPSim > Open BPSim Manager').
  2. Create a Business Process Simulation Artifact named Calendar Based Support Process Simulation.
  3. Select the Package containing the corresponding BPMN 2.0 model.
  4. Open the diagram containing the model to be simulated.

Calendars

  1. On the 'Configure' tab of the Configure BPSim window, click on the icon in the toolbar. The 'Edit BPSim Calendars' dialog displays.
  2. Click on the New button to display the 'Event Recurrence' dialog and complete the fields as described here, to create a calendar. (You will create two calendars.)
  3. In the 'Event Time' panel, set 'Start' to 08:00AM and 'End' to 05:00PM.
  4. In the 'Recurrence Pattern' panel select 'Weekly' and select the checkboxes against 'Monday' through to 'Friday'.
  5. In the 'Range of recurrence' panel set 'Start' to '02/11/2020' and select 'No end date'.
  6. Click on the OK button. You are prompted to enter a Calendar name; overtype Calendar_1 with 'Weekdays' and click on the OK button.
  7. Click on the New button again and repeat steps 3 to 6 with these values:
         -  'Start' - 08:00AM
         -  'End' - 05:00PM
         -  'Weekly'
         -  'Saturday' and 'Sunday'
         -  'Start' to '07/11/2020' and 'No end date'
         -  Overtype Calendar_2 with 'Weekend'
  8. Click on the OK button.

Duration

On the diagram, click on the Calendar Based Support Process Simulation BPSim Artifact and, on the 'Configure' tab of the Configure BPSim window, with the 'Calendar' field set to '----None----', create or edit this ScenarioParameter:

  • Duration - with a Constant value of 0000 002:10:00, which means 0 days, 2 hours and 10 minutes

Customer arrivals

On the diagram, click on the Customer calls in StartEvent and, on the 'Configure' tab of the Configure BPSim window, create or edit this Control parameter:

  • InterTriggerTimer - Value: 0 00:00:00, with the 'Calendar' field set to '----None----' (this default value is necessary)
  • InterTriggerTimer - Value: 0 00:20:00, with the 'Calendar' field set to 'Weekdays'
  • InterTriggerTimer - Value: 0 01:00:00, with the 'Calendar' field set to 'Weekends'

Processing Times

On the diagram, click on the Service Customer Activity and, on the 'Configure' tab of the Configure BPSim window, create or edit this Time parameter:

  • ProcessingTime - Value: 0 00:00:00, with the 'Calendar' field set to '----None----' (this default value is necessary)
  • ProcessingTime - Value: 0 00:50:00, with the 'Calendar' field set to 'Weekdays'
  • ProcessingTime - Value: 0 00:40:00, with the 'Calendar' field set to 'Weekends'

Resources

On the diagram, click on the Support Resource and, on the 'Configure' tab of the Configure BPSim window, create or edit this Resource parameter

  • Quantity - Value: 0; Calendar, with the 'Calendar' field set to '----None----' (this default value is necessary)
  • Quantity - Value: 2; Calendar, with the 'Calendar' field set to 'Weekdays'
  • Quantity - Value: 1; Calendar, with the 'Calendar' field set to 'Weekends'

Resource Selection (allocation)

On the diagram, click on the Service Customer Activity and, on the 'Configure' tab of the Configure BPSim window, with the Calendar field set to '----None----' check that the 'Values' field for the Resource parameter 'Selection' is set to:

bpsim::getResource('Support',1) as an expression

This expression is loaded from your BPMN model by default. You can do some advanced configurations for resource selection for a task.

Run Simulation

Weekdays

  1. Click on the 'Calendar' field and select 'Weekday'.
  2. Click on the 'Execute' tab and on the toolbar icon.

A file with the name Calendar Based Support Process Simulation - Result is generated. This report file contains the result for a weekday simulation, which is displayed on the 'Review' tab of the Configure BPSim window, on the 'Standard Results Report' tab.

Weekends

  1. Click on the 'Calendar' field and select 'Weekend'.
  2. Click on the 'Execute' tab and on the toolbar icon.

The Calendar Based Support Process Simulation - Result file is updated to show the result for a weekend simulation and displayed on the 'Review' tab of the Configure BPSim window, on the 'Standard Results Report' tab.

In each case, check the match between the result file and our analysis with pen and paper.