Structure, Behavior over Time, and Emergence
I tend to think of structure in a system dynamics simulation as a hierarchy of objects that provide insight into the interrelationships of the various objects.
System Dynamics 'Structure' is a hierarchy of objects assembled in the following process:
A. You define the boundary of the system.
1. You identify the feedback loops.
a. You identify the stocks
b. You identify the flows
1. You articulate the policies as flow equations
Note that two variables, stocks and flows, capture ALL the aspects of the system under study. And, the flows capture all the information on the policies of the system under study.
These processes are the building blocks of simulations.
Everything in the universe is a process. EVERYTHING.
Simulation Science is commercially very valuable stuff. Think billions of dollars not millions.
In business, we create objects that are assembled into representations of workflow processes with mapping to data warehouses for real-time information access.
In nature, like in a biochemical process, we can create a simulation model that captures with some degree of fidelity the processes that we wish to better understand (like production of an amino acid in bacteria).
Stocks, such as a stock of customers, are accumulations of many autonomous humans (agents). The inflow of new customers captures all the information on the policies (such as marketing) that drive the accumulation of customers. The outflow of customers captures all the information on the policies (such as poor customer service) that drive the depletion of customers.
Steve Guerin at Redfish Group refers to these as 'aggregated super-agents.' Dr. Suarez at in Business Administration at Trinity University refers to them as 'upper-level agents.' Others refer to them as 'stocks.' Others refer to them as 'levels.' I call them 'bathtubs.'
Behavior over time EMERGES from structure. I use EMERGENCE as a concept because all too often the behavior of a system is counter-intuitive to what we actually observe; it arises from nothing, yet is clearly visible. Some explain, where possible, behavior over time as resulting from the interaction of multiple feedback loops and the concomitant switching loop dominance.
That is, I think that the ABM folks (at Santa Fe Institute, Trinity University and other spots around the world) and the SD folks (at MIT, LBS, WPI, LSE and other spots around the world) have their own particular jargon which, in my not so humble opinion, all means something similar – life is not reducible to a simple set of deterministic and solvable equations.
That is, I argue that the concept of 'emergence' is related or perhaps even the same as the SD concepts of 'behavior over time' as a result of structure?
Of the interesting systems for study in the world, 99.99% are not solvable by humans without the aid of computers. And, many of those 99.99% of non-linear systems are not 'solvable' with mathematics known to humans.
This should really irritate a lot of people because everyone keeps trying to find some Newtonian-like super-equation for biology that will 'answer' all our questions, but no one will ever find it. It is a will-o-wisp.
We can only solve the problems of the business, nations and the world by the close and intimate interaction between humans and computers. This interaction must be governed by an appreciation of reality as understood through the lens of Simulation Science, that is, complexity science, chaos theory, nonlinear science – choose the jargon that you like.
That is, this must always be kept in mind, ALL models are false, some are useful and some are dangerous.
There are NO point predictions. No ULTIMATE answers. No TRUTH.
There is only foresight into plausible and probable future scenarios that may or may not happen.
More and more I'm thinking that system dynamics, aggregated super agents, upper level agents, etc. ad nausea, are the 'physics of biology;' the 'meta-engineering' of life through the wonderful, yet blind and simple algorithmic process of evolution by natural selection of agents that replicate.
Why is this important? Well, Simulation Science is incredibly well-suited to studying human-designed systems like global businesses, surfacing mental models and enabling humans to re-design and manipulate these systems to achieve goals -- like making more money.
Before the 21st century, physicists and mathematicians were the 'gods' of science. Think of Newton, Leibniz, Kelvin, Fermi, Einstein. The 21st century 'gods' of 'science' are the biologists, computer scientists, artists and engineers – people who are well-versed in the power and manipulation of emergence (behavior over time) in everyday life. Think of Darwin, Andronov, Forrester, Kauffman.
Why Should I Care About Simulation Science?
2006 - The Tipping Point for Simulation Science
Selling Simulation Science
What is Simulation Science?
Warmly,
Justin Lyon
© 2005 Justin Lyon. All Rights Reserved.
Reproduction permitted with reference to author: Justin Lyon.
System Dynamics 'Structure' is a hierarchy of objects assembled in the following process:
A. You define the boundary of the system.
1. You identify the feedback loops.
a. You identify the stocks
b. You identify the flows
1. You articulate the policies as flow equations
Note that two variables, stocks and flows, capture ALL the aspects of the system under study. And, the flows capture all the information on the policies of the system under study.
These processes are the building blocks of simulations.
Everything in the universe is a process. EVERYTHING.
Simulation Science is commercially very valuable stuff. Think billions of dollars not millions.
In business, we create objects that are assembled into representations of workflow processes with mapping to data warehouses for real-time information access.
In nature, like in a biochemical process, we can create a simulation model that captures with some degree of fidelity the processes that we wish to better understand (like production of an amino acid in bacteria).
Stocks, such as a stock of customers, are accumulations of many autonomous humans (agents). The inflow of new customers captures all the information on the policies (such as marketing) that drive the accumulation of customers. The outflow of customers captures all the information on the policies (such as poor customer service) that drive the depletion of customers.
Steve Guerin at Redfish Group refers to these as 'aggregated super-agents.' Dr. Suarez at in Business Administration at Trinity University refers to them as 'upper-level agents.' Others refer to them as 'stocks.' Others refer to them as 'levels.' I call them 'bathtubs.'
Behavior over time EMERGES from structure. I use EMERGENCE as a concept because all too often the behavior of a system is counter-intuitive to what we actually observe; it arises from nothing, yet is clearly visible. Some explain, where possible, behavior over time as resulting from the interaction of multiple feedback loops and the concomitant switching loop dominance.
That is, I think that the ABM folks (at Santa Fe Institute, Trinity University and other spots around the world) and the SD folks (at MIT, LBS, WPI, LSE and other spots around the world) have their own particular jargon which, in my not so humble opinion, all means something similar – life is not reducible to a simple set of deterministic and solvable equations.
That is, I argue that the concept of 'emergence' is related or perhaps even the same as the SD concepts of 'behavior over time' as a result of structure?
Of the interesting systems for study in the world, 99.99% are not solvable by humans without the aid of computers. And, many of those 99.99% of non-linear systems are not 'solvable' with mathematics known to humans.
This should really irritate a lot of people because everyone keeps trying to find some Newtonian-like super-equation for biology that will 'answer' all our questions, but no one will ever find it. It is a will-o-wisp.
We can only solve the problems of the business, nations and the world by the close and intimate interaction between humans and computers. This interaction must be governed by an appreciation of reality as understood through the lens of Simulation Science, that is, complexity science, chaos theory, nonlinear science – choose the jargon that you like.
That is, this must always be kept in mind, ALL models are false, some are useful and some are dangerous.
There are NO point predictions. No ULTIMATE answers. No TRUTH.
There is only foresight into plausible and probable future scenarios that may or may not happen.
More and more I'm thinking that system dynamics, aggregated super agents, upper level agents, etc. ad nausea, are the 'physics of biology;' the 'meta-engineering' of life through the wonderful, yet blind and simple algorithmic process of evolution by natural selection of agents that replicate.
Why is this important? Well, Simulation Science is incredibly well-suited to studying human-designed systems like global businesses, surfacing mental models and enabling humans to re-design and manipulate these systems to achieve goals -- like making more money.
Before the 21st century, physicists and mathematicians were the 'gods' of science. Think of Newton, Leibniz, Kelvin, Fermi, Einstein. The 21st century 'gods' of 'science' are the biologists, computer scientists, artists and engineers – people who are well-versed in the power and manipulation of emergence (behavior over time) in everyday life. Think of Darwin, Andronov, Forrester, Kauffman.
Why Should I Care About Simulation Science?
2006 - The Tipping Point for Simulation Science
Selling Simulation Science
What is Simulation Science?
Warmly,
Justin Lyon
© 2005 Justin Lyon. All Rights Reserved.
Reproduction permitted with reference to author: Justin Lyon.
posted by Justin Lyon at
7:10 PM
2 Comments:
Hi Justin... not a comment on this blog post but on your ode to Texas statement :-)
Tell me, if Texas is so good, what are you doing in London????
Cheers, Carol
By
Word Mincer, at 9:07 PM
Carol,
Touche! I actually split my time between USA (NY, CO, TX), Portugal, Honduras, UK (London) and several other wonderful places. Basically, I live on Earth and enjoy all of it. Interesting blog you've got there. Tell me more about yourself!
By
Justin Lyon, at 4:54 PM
Post a Comment
<< Home