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James Sokolowski

Systems Dynamic Modelling - And Top Tips for Naming

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Edited by James Sokolowski, Saturday, 18 May 2019, 02:14

Picking and Naming Variables

The choice of words is vital.  Each variable must be a noun. Avoid the use of verbs or directional adjectives.  For any variable, always have in mind a specific unit of measure so that the variable can be quantified.  

Basic Tips

identify loop types using R or B to signify reinforcing or balancing.  Always circle the R or B with a small curve travelling in the same direction as the feedback loop itself.

Useful Images

Signing Rules

Balancing

Puzzling Feedback

Reinforcing Loops



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James Sokolowski

Two new books to help me understand Systems Dynamic Modelling

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Edited by James Sokolowski, Wednesday, 15 May 2019, 18:21


A picture of environmental scientist and activist Donella Meadows

Today I discovered work by the environmental scientist and activist Donella Meadows. She contributed to the construction of a System Dynamic model called World3, which attempted to computer simulate human population growth.  I found a link to an version of the World3 model online (although I can't verify its authenticity) https://insightmaker.com/insight/1954/The-World3-Model-A-Detailed-World-Forecaster

As far as I can tell, Donella Meadows was convinced the population of the world will outgrow the world's capacity to support life within the next 100 years.  She wrote a book called Limits to Growth which sold over 10 million copies.  I've just purchased this book, because I'm fascinated with what she has to say. She devoted the rest of her life to living in a completely sustainable "closed-loop".

However, I just can't subscribe to apocalyptic views and dooms-day theories. Humankind has always lived with fear and dread of their own survival.  Jay Forrester (1997) is quoted in saying  "that Systems Dynamics demonstrates how most of our own decision-making policies are the cause of the problems that we usually blame on others."  Surely this is at the very natural of what it is meant to be "human."  When man designed a bicycle, he also created the problem of it not being fast.  When man put a engine in the bicycle, he also created the problem of it being too fast that people died.  The human solution was not to stop riding motorbikes and settle for slow bicycles! No, the solution was design faster bikes and better crash helmets.

Humans create solutions, which create new problems, which result in solutions to new problems.  Surely this is how evolution is meant to work.  I've just purchased a second book call Why e=mc2, and Why Does It Matter?  I'm convinced that Einstein's theory of relativity is a missing link that debunks sustainability theories.  Nature exists in cycles of creation, then destruction, but there still exists a "constant" in the equation.  Surely that "constant" is alternatively called growth, evolution or progress?

World3 SD model

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