Modeling Kanban Scheduling in Systems of Systems

Alexey Tregubov, Jo Ann Lane

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Outline Problem statement Research approach: Kanban process Overview of KSS Network Benefits of KSS Simulation model Simulation results

Health care example Complex example

Future work

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Problem statement In SoS environments the following problems observed:

Lack of visibility: What is going on at the project level? What is the current status of SoS capabilities?

How to expedite certain urgent capabilities? Everything is critical but nothing is done Every constituent team establish their own

priorities

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Research approach: Kanban process Kanban in manufacturing industry:

It is a system to control the logistical supply/demand chain. Toyota,1953.

Kanban as part of lean concept: “Pull” instead of “push” in demand Kanban is part of Just in time (JIT) delivery approach

Kanban in a software engineering (as a process): Visualized work flow – kanban boards Limit WIP Feedback and collaboration to improve the flow

Kanban in System of System environments: Kanban scheduling in work prioritization Value based work prioritization based on SoS capabilities,

balanced with single system needs Visualization

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Overview of KSS Network

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Benefits of using KSS Eliminate waste

Minimize context switching Limit work in progress

Make process more visible and transparent Kanban boards

Increased value delivered earlier Value-based work prioritization

Reduce governance overhead

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Cost context switching in multitasking

1 project 2 project 3 project 4 project 5 project0.00

20.00

40.00

60.00

80.00

100.00

120.00

Percent of Time on Project

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Simulation model

Discrete event simulation: Inputs:

Event scenario: a sequence of events that describes how network evolves over course of their execution

Team configuration: structure of teams, resource/specialties allocation

Simulation configuration: stop condition Outputs:

Sequence of network states Analysis: various indicators of effectiveness

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Simulation model: Kanban scheduling

All work items (WI) prioritized according to their business value

Every WI has a class of service: Standard, Important, Date Certain, Critical Expedite

Limiting work in progress: work in progress is never interrupted unless new work has a Critical class of service work is suspended by prerequisites

Visualization: kanban boards for each team.

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Health care example of KSS Network

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Example: capabilities to requirements to products

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Example: capabilities to requirements to products

Value = 60

Value = 20

Value = 10

Value = 10

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Example: capabilities to requirements to products

Value = 60

Value = 20

Value = 10

Value = 10

2050

20

40

10

10

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Example: network structure & scenario

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Example: outputs

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Example: simple scenarioValue:

0 5 10 15 20 25 30 350.00

200.00

400.00

600.00

800.00

1000.00

1200.00

random kss

Time

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Example 2: complex scenario

10 teams (20 members each) + system engineering team.

20 new capabilities at start. Each capability unfolds into 30 requirements

on average Each requirement unfolds into 9 tasks on

average. Each tasks takes 3-15 days. There are 5 expedite tasks that cause blocked

work (blocked tasks)

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Example 2: value comparison

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 780

10000

20000

30000

40000

50000

60000

KSS

Value-neutral (random selec-tion)

LIFO

Time

Value

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Example 2: number of suspended tasks

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 780

5

10

15

20

25

30

35

KSS

Value-neutral (random selection)

LIFO

Time

Number of Suspended

Tasks

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Example 2: work items in progress

0 3 6 9 12 15 18 21 24 27 30 33 36 39 42 45 48 51 54 57 60 63 66 69 72 75 780

50

100

150

200

250KSS

Value-neutral (random selec-tion)

LIFO

Time

WIP

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Example 2: total time spent (schedule)

KSS Value-neutral (random selection) LIFO61

62

63

64

65

66

67

68

69

70

71

Total schedule (person-days)

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Example 2: total effort

KSS Value-neutral (random selection) LIFO440

460

480

500

520

540

560

580

600

Total effort (days)

Effort requiredif there are interruptions

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Example 2: context switching

KSS Value-neutral (random selection) LIFO0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00

90.00

Effort on context switching(person-days)

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Conclusion: future work

Pilot the Kanban scheduling with several organizations

Fine-tune the simulator using empirical data and organizations’ feedback

Scale up the cases we run through the simulator

Refine and calibrate cost models

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Questions & answers

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References Waldner, Jean-Baptiste (September 1992). Principles of Computer-Integrated

Manufacturing. London: John Wiley. pp. 128–132. ISBN 0-471-93450-X. "Kanban". Random House Dictionary. Dictionary.com. 2011. Retrieved April 12,

2011. Ohno, Taiichi (June 1988). Toyota Production System - beyond large-scale

production. Productivity Press. p. 29. ISBN 0-915299-14-3. Richard Turner, Jo Ann Lane, Goal-question-Kanban: Applying Lean Concepts

to Coordinate Multi-level Systems Engineering in Large Enterprises, Procedia Computer Science, Volume 16, 2013, Pages 512-521, ISSN 1877-0509, (http://www.sciencedirect.com/science/article/pii/S1877050913000550)

Torgeir Dingsøyr, Sridhar Nerur, VenuGopal Balijepally, Nils Brede Moe, A decade of agile methodologies: Towards explaining agile software development, Journal of Systems and Software, Volume 85, Issue 6, June 2012, Pages 1213-1221, ISSN 0164-1212, (http://www.sciencedirect.com/science/article/pii/S0164121212000532)

Woods D. Why Lean And Agile Go Together : [Digital document], (http://www.forbes.com/2010/01/11/software-lean-manufacturing-technology-cio-network-agile.html). Verified on 7/7/2013.

Gerald Weinberg, Quality Software Management: Vol1. Systems Thinking. 1991