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in d ealing with complexity ENGN2219/COMP6719 2020 - - PowerPoint PPT Presentation

Aug 06, 2023 182 likes •766 views

The Role of Simulation in d ealing with complexity ENGN2219/COMP6719 2020 Shayne.Flint@anu.edu.au Research School of Computer Science College of Engineering and Computer Science Agenda Thinking about complexity Dave

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The Role of Simulation

in dealing with complexity

Shayne.Flint@anu.edu.au Research School of Computer Science College of Engineering and Computer Science

ENGN2219/COMP6719 – 2020

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Agenda …

  • Thinking about complexity

– Dave Snowden’s Cynefin Framework

  • Dealing with complexity

– System Dynamics – Boyd’s OODA loop

  • The role of simulation

– Brooks’ Law example

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Thinking About Complexity…

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Thinking about complexity …

  • The Cynefin sense-making framework

– Pronounced “KUN-iv-in” (It’s a Welsh word!) – Created in 1999 by Dave Snowden – http://cognitive-edge.com

  • We require different kinds of thinking for

– Simple Problems – Complicated Problems – Complex Problems – Chaotic Problems

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Unpredictable

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Predictable

The Cynefin Sense-making Framework

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Predictable

Unpredictable

The Cynefin Sense-making Framework

Complicated Simple

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Predictable

Complex

The Cynefin Sense-making Framework

Complicated

Unpredictable

Chaotic Simple

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Dealing with Complexity

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Dealing with complexity

  • Experimentation is at the core

– Probe – with safe to run experiments – Sense – what works & what doesn’t – Respond – with emergent practices

  • System Dynamics modeling and simulation can

help

  • We will also look at why Agility is important

when dealing with complexity

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System Dynamics

  • An approach to understanding the

behavior of complex systems over time

– Developed by Jay Forrester at MIT in the 1950’s – Originally focussed on industrial processes – Now widely used for policy analysis and design

  • Systems are represented using

– Causal Loop Diagrams (CLD) – Stock and Flow Diagrams (SFD)

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CLD Example – using Exit Mould

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM

Mould on my bathroom tiles

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX

+

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX

+

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE

  • +

+

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles delay

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE

  • +

+

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles Exit Mould damages grout and tile surface

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE PROBLEM PROBLEM

  • +

+ +

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles Exit Mould damages grout and tile surface Damage encourages growth of deep mould

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CLD Example – using Exit Mould

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE PROBLEM PROBLEM

  • +

+ + +

Mould on my bathroom tiles Apply Exit Mould and wipe down tiles Exit Mould damages grout and tile surface Damage encourages growth of deep mould

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“Fixes That Fail”

This is an example of a System Archetype

(a common pattern of behaviour)

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Other Fixes that Fail …

  • The war on terror
  • Building freeways
  • Borrowing money to pay interest
  • Cutting maintenance and repair costs

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM

Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX

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Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX

+

Increase overtime Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX

  • +

Increase overtime Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE

  • +

+

Increase overtime Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE

  • +

+

Increase overtime Physical and mental health issues Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE PROBLEM PROBLEM

  • +

+ +

Increase overtime Physical and mental health issues Staff Shortage

(cannot employ new people)

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Dealing with a staff shortage …

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SYMPTOM SYMPTOM FIX FIX UNEXPECTED CONSEQUENCE UNEXPECTED CONSEQUENCE PROBLEM PROBLEM

  • +

+ + +

Increase overtime Physical and mental health issues Increased sick leave Staff Shortage

(cannot employ new people)

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There are many such archetypes …

  • System Archetypes describe patterns of

behavior that surface in many different domains

  • They help us

– think about the possible behavior of complex systems – understand why a complex system behaves the way it does, and – identify things we can do to change that behavior (ie. the things that work and don’t work).

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The need for agility

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John Boyd

  • Fighter pilot
  • Military, sport and

business strategist

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Boyd’s OODA Loop

  • A continuous process of learning and change in

competitive environments

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Speed is the key to success

  • Success comes from getting around your OODA loop

more quickly than your competitor

– Business, Nature, Sport, Politics …

  • If your competitor is quicker than you:

– Your competitor's behavior will eventually appear chaotic – you will be confused – You will make bad decisions - based on ‘Orientation’ and ‘Observations’ that are no longer valid – You will lose or fail

  • Complex systems often evolve rapidly

– You need to experiment, learn and act quickly

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The role of simulation

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How can simulation help

  • We can simulate the behavior of complex systems

– eg. System Dynamics Stock & Flow models

  • We can do this quickly

– In order to get through our OODA loop quickly

  • We can run many simulations based on different

parameters

– That is, we can run a series of different ‘experiments’ – To find out what works & what doesn’t

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SFD Simulation Example - Brooks’ Law

  • Fred Brooks

– Turing Award 1999 – Author of “The Mythical Man-Month” – Author of “No Silver Bullet”

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SFD Simulation Example - Brooks’ Law

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“Adding manpower to a late software project makes it later.”

Brooks’ Law

  • Note that in his book ‘The Mythical Man-Month’, Brooks

says that this law is an ‘outrageous oversimplification’.

  • In reality, adding people to a project is a complex problem
  • We can explore this problem using System Dynamics and

Simulation.

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SFD Simulation Example - Brooks’ Law

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https://insightmaker.com/insight/4648/Clone-of-Brooks-Law

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Live Demonstration

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SFD Simulation Example - Brooks’ Law

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  • No new developers at day 100
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SFD Simulation Example - Brooks’ Law

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  • 5 new developers at day 100
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SFD Simulation Example - Brooks’ Law

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  • 15 new developers at day 100
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SFD Simulation Example - Brooks’ Law

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  • 15 new developers at day 100, decreased communications
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SFD Simulation Example - Brooks’ Law

  • But, how do we reduce communication?

– Fewer meetings? – Restrictions on email use? – ...

  • … and what are the consequences?

– More mistakes? – Duplication of work? – ...

  • Additional complexity …

– Need to add these aspects to the model

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Exploring online SFD simulations

  • https://insightmaker.com

– Free & Open – Supports Collaboration – Huge repository of models you can play with

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Exploring online SFD simulations

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https://insightmaker.com/insight/12842/2014-Weather-Climate-E xtreme-Loss-of-Arable-Land-and-Ocean-Fertility-The-World3-Mo del-Forecaster

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Exploring online SFD simulations

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https://insightmaker.com/insight/101411/Air-Transport-Causal-Loop-Diagram

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Exploring online SFD simulations

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https://insightmaker.com/insight/7682/Implementing-Chronic-Care-Management

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Exploring online SFD simulations

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https://insightmaker.com/insight/188271/Upgrade-of-Kermack-McKendrick-Epidemic-SIR-Infectious-Disease-Model-Metrics-by-Guy-Lakeman

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Additional Material …

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System Dynamics

– Wikipedia, “System Dynamics”

  • https://en.wikipedia.org/wiki/System_dynamics

– Insight Maker, “Free modeling and simulation in your browser”

  • https://insightmaker.com

Cynefin Framework

– Snowden, “Making Sense of Complexity”, Lean, Agile & Scrum Conference 2013

  • https://www.youtube.com/watch?v=y6RfqmTZejU

– O’Sullivan, “Domain Driven Design for Everyone Else”, dev.to

  • https://dev.to/barryosull/domain-driven-design-for-everyone-else-a9

– Snowden and Boone, “A Leader’s Framework for Decision Making”, Harvard Business Review, Nov 2007

  • https://hbr.org/2007/11/a-leaders-framework-for-decision-making

OODA Loops

– Adolph, “What lessons can the agile community learn from a maverick fighter pilot?”, Agile’06

  • https://ieeexplore.ieee.org/document/1667567/
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Additional Material …

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Fred Brooks

– Wikipedia, “Fred Brooks”

  • https://en.wikipedia.org/wiki/Fred_Brooks

– Brooks, Fredrick P. (1975). “The Mythical Man-Month: essays in software engineering.” Reading, Massachusetts: Addison-Wesley.

  • Amazon

– Brooks, F. P., Jr. (1987). “No Silver Bullet – Essence and Accidents of Software Engineering”. Computer. 20 (4): 10-19

  • ACM
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Questions ?

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