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BPMN Process Simulation Example

Simulation is a technique that helps business analysts simulate the execution of business process for studying the resource consumption (e.g. Human resources, devices, etc.) throughout a process, identifying bottlenecks and improving the current business by process refinement and resources re-allocation. Simulation is the tool that assists you to perform simulation. It includes not only the visual simulation ability, but also charts generation functions. In this tutorial, we will study a business process of performing body check, and make use of the simulation tool to find out the possible changes that can make the process more efficient.

Compatible edition(s): Enterprise, Professional

  • February 19, 2010
  • Views: 22,273
  • PDF

  1. Download Body Check.vpp. You can also find this file at the bottom of this tutorial.
  2. Open the downloaded .vpp file in Visual Paradigm. To open a project, select Project > Open from the application toolbar.
  3. Open the business process diagram A cycle of body check.
  4. Study the process. The diagram models the current process of performing body check in a health center. It starts from processing a client's registration by receptionist, then the nurse check the client's blood pressure, the X-Ray specialist test the client's lung function, and finally the body-check officer prepare a report and present it to user.
    Sample business process diagram
    Now, we want to know the answer of the following questions, which simulation can help:
    • How long it takes to finish a process?
    • What is the optimal allocation of resources like staff (e.g. specialist), rooms (e.g. Meeting room) or devices/machines (e.g. X-Ray machine)?
    • Does the process works well against a large amount of clients?
  5. In order to run simulation, we need to provide additional information to the business process diagram, such as the current resource consumptions and durations of each activity. Select Modeling > Simulation from the application toolbar. The Simulation Control Panel will appear for you to set simulation details like resource consumption and duration of activities.
    Open simulation panel
  6. Let's start by recording the resource consumption of the current process. On the right hand side of the diagram you can configure the resources that is available to the process. Available resources mean the resources that can be used, but not necessarily be used. For example, the health center may have 20 wheelchairs available, while only 5 to 6 is needed. Now, click Add to add an available resource X-Ray Room, typed Room with 2 as amount. Add also a resource Meeting Room, typed Room with 1 as amount. Other resources like wheelchairs, toilets are irrelevant to the process, and can be ignored.
    Resource set
  7. The testing of lung function need to be done in an X-Ray room. Select task Test Lung Function in diagram. At the Simulation Control Panel click Add for Required Resources and select X-Ray Room from the popup menu. Keep amount be 1 as only one room is needed to perform a lung function testing.
    Required resource added
  8. Select the task Present Report. Add Meeting Room as a required resource with 1 as amount.
    Required resource added
  9. We also need to set the duration of completing each task. Select task Process Registration. Set at the Simulation Control Panel its duration to be 3, meaning that it takes 3 minutes to complete a registration process.
    Duration set
  10. Set the duration of other tasks.
    Task Duration
    Check Blood Pressure 2 minutes
    Test Lung Function 6 minutes
    Prepare Report 2 minutes
    Present Report 5 minutes
  11. The lanes such as Receptionist, Nurse, etc are the participants of the body check process. They are also resources that can affect the efficiency of process. We need to set the number of each lane. Select lane Receptionist in diagram and set instance to be 1 at the Simulation Control Panel. This mean that one and only one receptionist is taking part in this process.
    Pool instance set
  12. Set the instances of other lanes.
    Lane Instance
    Nurse 1
    X-Ray Specialist 1
    Body-check Officer 1
  13. Click Show Scenario at the Simulation Control Panel. Scenarios are ways of running through the process. If a process contains gateways, you can define multiple scenarios to represent the execution of different paths due to the forking.
  14. Take this process as example. Click Add to add an input, with name Peak hour, 10 as instances. This means that at peak hour(s), there will be 10 clients who need to perform body check. With this setting, the path (as presented in the Path list) will be executed 10 times during process simulation.
    Scenario added
  15. Click the Start button to start process simulation.
    Start simulation
  16. Study the result of simulation. Below is a description of some of the key area that you should pay attention to:
    Simulating
    No. Description
    1 The green running circle stands for job(s) that is/are executing at the attaching task/activity. The number inside the circle stands for the number of jobs being executed.
    2 The red inverted triangle stands for job(s) that is waiting to be executed. The number inside the triangle stands for the number of pending jobs. It is attached to the end of flow to represent the need of being executed by the coming flow object.
    3 The clock shows the time elapsed.
    4 The Resources table show the dynamic resource consumption. It will be updated throughout the process simulation to reflect the use of resources at particular instant.
  17. It looks like the simulation process is a bit too fast. Click Stop. Change the scale to 10 mins scale and play again.
    Adjusting scale
  18. It's a bit slower now. By observing the occurrence of inverted triangle, we can determine where the bottleneck occur, if any, and to think of the possible improvements in further. With this body check process, we notice there are always pending jobs at task Test Lung Function.
    BPD under simulation
  19. Now, we need to decide how to improve the process. Since the bottleneck is at lung function testing, we need to decide how to speed it up. There are several possible actions we can do:
    • Reduce the duration of lung function testing
    • Employ more specialist(s) to share the work load
    Since the duration of proper lung function testing is fixed, the first action is impossible. We shall take the second action.
  20. Select lane X-Ray Specialist, change instance from 1 to 2.
    Instance updated
  21. Click Start to simulate again.
  22. Strangely, the time it takes to finish the process remain the same, why? If you observe the result of simulation, you can see that the task Test Lung Function is no longer the bottleneck, due to the addition of X-Ray specialist. However, the tasks Prepare Report and Present Report now become the bottleneck.
    Bottleneck
  23. Let's employ one more body check officer to help. Select lane Body-check Officer, change instance from 1 to 2.
    Updated lane instance
  24. Further to employing an officer to help, we need to reserve one more meeting room. Change the amount of available meeting room from 1 to 2.
    Resource added
  25. Simulate again.
  26. It now takes 50 minutes to complete the whole process. By comparing with the original process, the improvements reduce 30 minutes operation time in total.
    There are other possible solutions instead of employing more staff. For example, we can computerize the process by not presenting report to client, but to print it out with clear description on each checked item, and let the client read himself. We may also buy advanced X-Ray machines to speed up the lung function testing process. Simulation does not recommend a solution to you, but to let you execute your idea of improvements easily through updating diagram content and resource allocation, and give you figures to show the effect of changes, to help you decide the best solution.
  27. Sometimes, just by watching the simulation outcome is not enough in finding out the bottleneck, especially when the diagram is large, and have many, many bottlenecks. In such cases, you can produce charts for simulation outcome, which helps quantify resource consumption and queuing time for each activity. Click Simulation Charts in Simulation Control Panel.
    Open simulation charts
  28. Study the chart in Completion page. The chart show the status of scenarios completion against time. Remember we have set 10 instances to scenario Peak hour? From the chart you can see the completion of the 10 instances throughout the process simulation. As time goes by, there will be more scenarios being completed, and less scenarios being processing.
    Completion chart
  29. Open the Resource Usage page. The chart here shows the level of resource consumption. In this example, both X-Ray room and meeting room are fully used (100%) within the process, which is ideal. But if you try to add 3 to 4 available X-Ray rooms, and review the chart, you will see that the peak usage will be less than 100% because some rooms are idles throughout the whole process. By studying this chart, you can adjust the amount of resources to apply to the process.
    Resource usage chart
  30. Open the Queue Time page. The chart here shows the time the flow objects spent on waiting, which corresponds to the time an inverted triangle appear during simulation. By studying the chart, we know that process registration now takes over 10 minutes in waiting, prepare and present report still take over 4 minutes after the improvement. By studying this chart, you can decide whether further improvements need to be carried out.
    Queue time chart



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