Creating queuing system simulations with enterprise architect sysml parametric models
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Creating queuing system simulations with enterprise architect sysml parametric models

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This presentation illustrates how to use Sparx Enterprise Architect Parametric Model features found in the Systems Engineering and Ultimate editions to simulate queuing systems.

This presentation illustrates how to use Sparx Enterprise Architect Parametric Model features found in the Systems Engineering and Ultimate editions to simulate queuing systems.

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Creating queuing system simulations with enterprise architect sysml parametric models Presentation Transcript

  • 1. Creating Queuing Systems Simulations with Sparx EA SysML Parametric Models 1 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting Add Performance Analysis to your EA Processes and Systems Models with Queuing Systems Simulations http://www.mypragmaticohesion.com/Queueing/index.htm
  • 2. Queuing Systems Simulation • This presentation illustrates how to use Sparx Enterprise Architect Parametric Model features found in the Systems Engineering and Ultimate editions to simulate queuing systems. • The presentation assumes that user is already familiar with the use of Parametric Models. We recommend reading the following reference for an introduction to Parametric Models: Embedded Systems Development using SysML Chapter 5. 2 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 3. Queuing Systems • Queuing Systems are generally made of waiting lines (also called queues) and processing centers that perform some operation or provide a service on people/items taken from queues. • A typical example would be customers waiting in line at a bank to be serviced by tellers or automated teller machines. 3 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 4. Queuing System Simulation Item Repository • We use the Enterprise Architect SysML Block Definition Constraint Blocks to define several generic modeling elements that will be combined to create Queuing System Simulation parametric models. 4 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 5. Queuing System Simulation Elements Repository • We have defined four main groups of modeling elements: – Source elements: they model the arrival of the queuing system items such as customers arrival or work items submission. – Queue elements: they model the waiting lines or queues of source items. No queue rules such as First In first Out (FIFO) or Last In First Out (LIFO) are enforced. – Service elements: they model actions performed on a source item when it is time to process or service it. – Routing elements: they model routing items between services and queues. • Each element behavior is scripted • The states of the Queuing System Simulation elements are evaluated at time intervals controlled by the progression of a global variable t representing the passage of time. 5 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 6. Queuing System Simulation Elements Repository • Source elements: – Custom Arrival: It generates a number of items at specific values of t. User defines the number of items created for any value of t. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemReposit... t output 6 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 7. Queuing System Simulation Elements Repository • Source elements: – Simple Source: It generates an item if the value of a random variable is between the parameters P1 and P2 bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepositor... P1 : Real output : RealP2 : Real 7 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 8. Queuing System Simulation Elements Repository • Queue elements: – Simple Queue: It is the first queue an item enters from a Source element. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] input : Real ItemsInQueue : Real output : Real 8 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 9. Queuing System Simulation Elements Repository • Queue elements: – Next Queue: It is a Queue that follows a Service element. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] input : Real ItemsInQueue : RealPreviousQueue : Real output : Real 9 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 10. Queuing System Simulation Elements Repository • Queue elements: – Sink: It is a Queue from which no items are taken from once they enter it. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepositor... input : Real ItemsInSink : RealPreviousQueue : Real 10 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 11. Queuing System Simulation Elements Repository • Queue elements: – Simple Buffer: It is a buffer that moves input items into output items. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] input : Real output : Real 11 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 12. Queuing System Simulation Elements Repository • Service elements: – Simple Service: It is a service center that does not create any defects. It processes one item at the time at a rate set by P. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] input : Real P : Real output : Real 12 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 13. Queuing System Simulation Elements Repository • Service elements: – Service with Defects: It is a service center that can create defects. It processes one item at the time at a rate set by P. It generates defective items at a rate set by DP bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] P : Real DP : Real output : Real defectOutput : Real input : Real passOutput : Real 13 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 14. Queuing System Simulation Elements Repository • Routing elements: – Splitter: It randomly routes an item to either output 1 or output 2 based on a splitting ratio P. bdd [Package] QueueSimulationItemRepository [QueueSimulationItemRepository] P input output1 output2 14 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 15. Queuing System Simulation Elements Repository • Routing elements: – Merger: It combines two inputs into a single output. bdd [Package] QueueSimulationItemRepository [QueueSimulationIte... input1 input2 output 15 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 16. Queuing System Simulation Models • We use the Enterprise Architect SysML Parametrics Property and Constraint Property objects to create Queuing System Simulation models. • An example of a model is presented next. 16 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 17. Work Items Queuing System Parametric Model par [Package] QueueingParametricModelExample [QueueingParametricModelExample] t WorkCreationOutput: SimpleBufferinput output m_UnassignedWorkQueue : SimpleQueue input ItemsInQueue UnassignedWorkQueue: SimpleBufferinput output output m_WorkAssignment: SimpleService P WorkAssignmentRate input output : SimpleBufferinput output m_WorkAssignedQueue : NextQueue input output ItemsInQueue PreviousQueue WorkCompletionRate : SimpleBufferinput output WorkAssignedQueue : SimpleBufferinput output WorkDefectRate m_WorkCompletionAndVerification : ServiceWithDefects P DP passOutput defectOutput : SimpleBufferinput output DefectiveWorkDetectedCount m_DefectiveWorkQueue : NextQueue input output PreviousQueue ItemsInQueueZeroRate m_WorkCompleted : Sink input ItemsInSink CompletedWorkCount PreviousQueue CompletionOutput input output WorkAssignmentOutput CustomSource : CustomArrival t output m_TotalWorkQueue : NextQueue input PreviousQueue output ItemsInQueue : SimpleBufferinput output TotalWorkSubmittedCount 17 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 18. Work Items Queuing System Parametric Model • In this model, Work items are submitted over time according to a custom schedule. • Work items once created enter an Unassigned Work Queue • The Work Assignment Service then assigns work items one at a time to a Work Assigned Queue • The Work completion and Verification Service then takes one job at the time from the Work Assigned Queue and completes it. Upon completion the Work item is tested for defects • If a Work item is not defective, it is added to the Work Completed Sink otherwise it remains in the Work Assigned Queue for re-processing • If a Work item is found defective, it is recorded in the Detected Defects Queue • The Detected Defects Queue only serves as a counter of the number of defective Work Items found. We could have used a Sink Queue Element instead but the behavior is the same as long as the Queue Output Rate parameter is set to zero. 18 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 19. Configuring and Running the Parametric Model 19 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 20. Simulation Results A 20 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 21. Simulation Results A Input Parameters Values t 0 to 200 step 0.05 Work Assignment Rate 0.5 Work Completion Rate 0.25 Work Defect Rate 0.15 ZeroRate 0 Outputs Min Max Mean Completed Work count 0 657 404 Defective Work detected 0 114 71.75 Work Assigned Queue 0 178 65.5 Unassigned Work Queue 0 115 12.67 Work is fully completed at t = 152.35 21 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 22. Simulation Results B 22 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 23. Simulation Results B (Higher Work Defect Rate) Input Parameters Values t 0 to 200 step 0.05 Work Assignment Rate 0.5 Work Completion Rate 0.25 Work Defect Rate 0.30 ZeroRate 0 Outputs Min Max Mean Completed Work count 0 657 352 Defective Work detected 0 301 153.6 Work Assigned Queue 0 232 117.8 Unassigned Work Queue 0 115 12.67 Work is fully completed at t = 187.65 23 Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting
  • 24. Copyrights (c) 2011-2013 Pragmatic Cohesion Consulting 24 Contact Didier at Pragmatic Cohesion Consulting to find out how to create Systems and Processes Performance Analysis Models with your Sparx EA SysML Edition http://pragmaticohesion.com/ Compute the following Performance Measures: • Workloads • Processing Times • Utilizations http://www.mypragmaticohesion.com/Queueing/index.htm Check the interactive Model at: