What can traffic inteach you aboutqueuingtheory<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />
Håkan Forss Lean/Agile Coach<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />
Little’s Law<br />Work-in-Process<br />Throughput<br />Cycle Time =<br />
Little’s Law<br />12<br />12 / min<br />1 min =<br />
Little’s Law<br />6<br />12 / min<br />0,5 min=<br />
Little’s Law<br />24<br />12 / min<br />2 min =<br />
20 sec<br />40 sec<br />With less Work-In-Process<br />Shorter cycle time<br />Better time to market<br />Faster feedback<...
TheoryofConstraints<br />
5<br />
Don’t allow inertia to cause a system constraint.<br />
Capacity = 4<br />Capacity = 6<br />Capacity = 6<br />Throughput = 4<br />You can never go faster than your bottleneck<br ...
Capacity = 4<br />Capacity >= 4<br />Capacity = 6<br />Throughput = 4<br />You can never go faster than your bottleneck<br...
Capacity = 4<br />Capacity = 6<br />Capacity >= 4<br />Throughput = 4<br />You can never go faster than your bottleneck<br...
Don’t allow inertia to cause a system constraint.<br />
Bottleneck at the end of the process<br />Work is backing up<br />Slowing down the process<br />Cycle times goes up<br />
Bottleneck at the beginning/middle of the process<br /> Work is drying up at the end of the processmaking workers idle<br />
?<br />
Non-instant availability resource<br />Looks like a bottleneck<br />
Non-instant availability resource<br />A resource that is not available all the time<br />Has required capacity but is not...
Don’t allow inertia to cause a system constraint.<br />
Exploit  your bottleneck<br />Bottlenecks should only work on bottleneck activities<br />Do whatever you can to make your ...
Don’t allow inertia to cause a system constraint.<br />
Subordinate to your bottleneck<br />Do what you can to always have work for the bottleneck<br />Do what you can to avoid p...
Subordinate to your bottleneck<br />Try to use you over capacity to alleviate the bottleneck of non bottleneck work<br />S...
Don’t allow inertia to cause a system constraint.<br />
Elevate your bottleneck<br />Expand the capacity at the bottleneck<br />Expensive as it usually will use bottleneck resour...
Don’t allow inertia to cause a system constraint.<br />
Don’t allow inertia to cause a system constraint.<br />
Balance demand to flow<br />
Wishful thinking<br />Capacity = 4<br />Demand = 6<br />Balance demand to flow<br />Capacity at the bottleneck will dictat...
Onlyonevehicleevery green period<br />
Balance demand to flow<br />An even flow can stabilize the process <br />Low work-in-progress<br />Keeps cycle time down <...
Slow down to go faster <br />Slowing down can stabilize the process flow<br />A stable process can go faster<br />
Håkan Forss<br />Mail: hakan.forss@avegagroup.se<br />Twitter: @hakanforss<br />Blog: http://hakanforss.wordpress.com/<br />
Recommended reading<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />
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What can traffic in stockholm teach you about queuing theory - Lean Kanban Central Europe 2011

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In this session you will learn about queuing theory and Theory of Constrains. By using real world examples of different traffic situations in Stockholm, illustrations and examples from Kanban boards you will see the similarities between them. You will lean how you can apply Theory of Constrains to find the bottleneck in your development process and how you can use this to continuously improve your development process.
This session is adding more details about Theory of Constrains than previous talks on this subject.

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  • Every process has at least oneOne is always a number oneWhen you break it number two will take it’s place
  • Identify the constraint
  • Very busy, all the timeWork piles up in front of themPeople downstream idle
  • There are two different types of bottlenecks: - Capacity contraint resource - a resource limited by capacity, like a bottle - non instantly available resource - a resource that is not available all the time
  • There are two different types of bottlenecks: - Capacity contraint resource - a resource limited by capacity, like a bottle - non instantly available resource - a resource that is not available all the time
  • Exploit the constraint
  • No task switchingNo idle timeOnly work on highest priority itemsOnly value-adding workNo wasted effortBest working conditions.
  • Subordinate to the constraint
  • Only high quality inputDon’twastevaluecreated by bottleneckDrum-buffer-ropeSubordinates need slackShare work.
  • Training and toolsCoaching and mentoringTeam retrospectivesIndividual improvementWorkspaceimprovementProcess improvementPairingMore resources
  • What can traffic in stockholm teach you about queuing theory - Lean Kanban Central Europe 2011

    1. 1. What can traffic inteach you aboutqueuingtheory<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />
    2. 2. Håkan Forss Lean/Agile Coach<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />
    3. 3.
    4. 4.
    5. 5.
    6. 6.
    7. 7. Little’s Law<br />Work-in-Process<br />Throughput<br />Cycle Time =<br />
    8. 8. Little’s Law<br />12<br />12 / min<br />1 min =<br />
    9. 9. Little’s Law<br />6<br />12 / min<br />0,5 min=<br />
    10. 10. Little’s Law<br />24<br />12 / min<br />2 min =<br />
    11. 11. 20 sec<br />40 sec<br />With less Work-In-Process<br />Shorter cycle time<br />Better time to market<br />Faster feedback<br />Makes problems visible faster<br />Are we working on the right things<br />
    12. 12. TheoryofConstraints<br />
    13. 13.
    14. 14.
    15. 15. 5<br />
    16. 16. Don’t allow inertia to cause a system constraint.<br />
    17. 17.
    18. 18.
    19. 19. Capacity = 4<br />Capacity = 6<br />Capacity = 6<br />Throughput = 4<br />You can never go faster than your bottleneck<br />The capacity at the bottleneck will dictate the capacity of the complete process<br />
    20. 20. Capacity = 4<br />Capacity >= 4<br />Capacity = 6<br />Throughput = 4<br />You can never go faster than your bottleneck<br />As long as capacity in front of the bottleneck is equal to or grater than the bottleneck you will go as fast as your bottleneck<br />Full use of a higher capacity in front of the bottleneck will make cycle time go up<br />
    21. 21. Capacity = 4<br />Capacity = 6<br />Capacity >= 4<br />Throughput = 4<br />You can never go faster than your bottleneck<br />As long as capacity is equal to or greater after the bottleneck you will go as fast as your bottleneck<br />Higher capacity after the bottleneck than at the bottleneck will not improve throughput over time<br />
    22. 22. Don’t allow inertia to cause a system constraint.<br />
    23. 23.
    24. 24.
    25. 25.
    26. 26. Bottleneck at the end of the process<br />Work is backing up<br />Slowing down the process<br />Cycle times goes up<br />
    27. 27.
    28. 28. Bottleneck at the beginning/middle of the process<br /> Work is drying up at the end of the processmaking workers idle<br />
    29. 29.
    30. 30.
    31. 31. ?<br />
    32. 32.
    33. 33. Non-instant availability resource<br />Looks like a bottleneck<br />
    34. 34. Non-instant availability resource<br />A resource that is not available all the time<br />Has required capacity but is not instantly available <br />
    35. 35.
    36. 36.
    37. 37. Don’t allow inertia to cause a system constraint.<br />
    38. 38. Exploit your bottleneck<br />Bottlenecks should only work on bottleneck activities<br />Do whatever you can to make your bottleneck 100% utilized <br />Try your hardest to avoid problems at you bottleneck <br />Time lost at the bottleneck is time forever lost for the process<br />
    39. 39. Don’t allow inertia to cause a system constraint.<br />
    40. 40.
    41. 41. Subordinate to your bottleneck<br />Do what you can to always have work for the bottleneck<br />Do what you can to avoid passing defects on to the bottleneck<br />Sub optimal performance for non bottlenecks can be accepted<br />
    42. 42. Subordinate to your bottleneck<br />Try to use you over capacity to alleviate the bottleneck of non bottleneck work<br />Sub optimal performance for non bottlenecks can be accepted<br />
    43. 43. Don’t allow inertia to cause a system constraint.<br />
    44. 44.
    45. 45. Elevate your bottleneck<br />Expand the capacity at the bottleneck<br />Expensive as it usually will use bottleneck resources <br />
    46. 46. Don’t allow inertia to cause a system constraint.<br />
    47. 47.
    48. 48. Don’t allow inertia to cause a system constraint.<br />
    49. 49. Balance demand to flow<br />
    50. 50. Wishful thinking<br />Capacity = 4<br />Demand = 6<br />Balance demand to flow<br />Capacity at the bottleneck will dictate the capacity of the process<br />Balance your demand to a continuous flow through the bottleneck<br />Higher demand than capacity will increase cycle time<br />
    51. 51. Onlyonevehicleevery green period<br />
    52. 52. Balance demand to flow<br />An even flow can stabilize the process <br />Low work-in-progress<br />Keeps cycle time down <br />Makes bottlenecks visible faster<br />
    53. 53.
    54. 54. Slow down to go faster <br />Slowing down can stabilize the process flow<br />A stable process can go faster<br />
    55. 55.
    56. 56.
    57. 57. Håkan Forss<br />Mail: hakan.forss@avegagroup.se<br />Twitter: @hakanforss<br />Blog: http://hakanforss.wordpress.com/<br />
    58. 58. Recommended reading<br />Håkan Forss - hakan.forss@avegagroup.se - @hakanforss<br />

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