Systems Thinking Nathaniel J. C. Libatique. A System Is More than the sum of its parts More than the sum of its parts Where the rules of the game are.

Systems Thinking

Nathaniel J. C. Libatique

A System Is

More than the sum of its parts

Where the rules of the game are as important

Composed of Elements and Interconnections

Invested with a Purpose

http://www.cellsignal.com/reference/pathway/Apoptosis_Overview.html

Ingredients

Collective Behavior Signaling and Computation AdaptationLarge scale networks with no central

control and simple rules give complex collective behavior, sophisticated signaling and information processing and adaptation via learning or evolution

“A system is more than the sum of its parts. It may exhibit adaptive, dynamic, goal-seeking, self-preserving, and sometimes evolutionary behavior.” (D. Meadows)• MAFIA

• Residents in MTUs• Sand on the road• Apoptosis• Trees

http://en.wikipedia.org/wiki/Corleone_crime_family

Elements vs. Interconnections Tree system: physical

flows and chemistry Sunny day lose water

pressure drop roots take in more

Roots see dry soil pressure loss signals closing of leaf pores

Colder temperatures nutrients pass from leaves to trunk and roots

Overall purpose of the tree is to grow

Purpose of the tree is nested within the purpose of the forest

fan.theonering.net/middleearthtours/ents.html

Nature. 2000 Nov 16;408(6810) Feedback control of intercellular

signalling in development. Freeman M. MRC Laboratory of

Molecular Biology, Cambridge, UK. [email protected]

The intercellular communication that regulates cell fate during animal development must be precisely controlled to avoid dangerous errors. How is this achieved? Recent work has highlighted the importance of positive and negative feedback loops in the dynamic regulation of developmental signalling. These feedback interactions can impart precision, robustness and versatility to intercellular signals. Feedback failure can cause disease.

http://www.ebi.ac.uk/microarray/biology_intro.html

http://www.cellsignal.com/reference/pathway/Angiogenesis.html

“The least obvious part of the system, its function or purpose, is often the most crucial determinant of the system behavior.” (D. Meadows)

• Purpose deduced from behavior, not necessarily stated goals… adiabatic frog, climate change policies vs. growth, corrupt government

• Purposes of subunits can add up to an unwanted overall behavior! … universities, government

Stocks and Flowsstock

inflow

stock

outflow

Fossil fuel, energy efficiency, energy policies and legislation ….

stock

inflow outflow

Coffee temperature

cooling

Room temperature

discrepancy

B

The greater the temperature difference, the faster the coffee will cool. Purpose of system is to reduce the discrepancy to zero.

Energy available for work

Metabolic mobilization of energy

Energyexpenditure

Body’s

stored energ

yDesired energyleveldiscrepa

ncy

Coffee intake

Balancing feedback: goal-seeking, stabilizing, regulating loop

B

Runaway Loops – Reinforcing Feedback. Arms race, accelerated climate change, inflation, erosion, epidemics

Money in bank account

Interest added

Interest rate

capitalinvestment

Fraction of Outputinvested

output

R

R

pg 31, Meadows

Machines/Factories Goods/Services

http://www.guardian.co.uk/world/2010/jan/28/human-rights-watch-hamas

Global Temp

CO2Production

Albedo

R

─

+

+

Melting permafrost peatlands at Noyabrsk, Western Siberia.http://www.terranature.org/methaneSiberia.htm 

A study published in the September 7th issue (2006) of Nature authored by Katey Walter of the University of Alaska, and Jeff Chanton of Florida State University reports that greenhouse gas is escaping into the atmosphere at a frightening rate.

Global Temp

CO2Production

TrappedGHGs

R+

Biomass

Why Systems Surprise

Series of visible events fool us: a river floods, a forest cut down, oil discovered, market crashes.

Interconnection between systems structure and behavior is hidden: interlocking stocks, flows and feedback loops

Page 92, Thinking in Systems

Spruce budworm

Budworm attacking spruce and fir for 400 year cycle now (tree ring records). White pine prime lumber

Annual DDT since 1950, still budworm resurgence, 1980 $12.5 M in New Brunswick

Fir – most competitive, spruce next, then birch

Fir threatens monoculture, worm opens forest.

Forest System

Fir builds up, worm’s favorite food Budworm population increases

nonlinearly Two to three warm dry springs

increase survivability Natural enemies cannot control

worms Drastic reduction of food supply

crashes the population! Oscillation

Drug Supply: Goals Addicts - high Enforcement Agencies - low Pushers – not to high not too low Citizens - Safety

Drug Supply System Enforcement agents cut imports at

border Drug supply goes down

Other stakeholders redouble efforts to push it back up: street prices go up addicts commit more crimes for their fix more profits at higher prices, suppliers

use profits to increase capital (planes boats)

Drug supply goes up

Resources D. Meadows, “Thinking in Systems”, Check

Google Bookshttp://books.google.com/books?

id=JSgOSP1qklUC&printsec=frontcover&dq=donella+meadows+systems+thinking&cd=1#v=onepage&q=&f=false

Steven Levitt: “Why do crack dealers still live with their moms?” http://www.youtube.com/watch?v=5UGC2nLnaes

http://www.pioneerentrepreneurs.net/presentations/An%20Introduction%20to%20System%20Dynamics.html

http://www.raczynski.com/pn/simball.htm

Powersim constructor lite Netlogo has a systems dynamics tool SCICOS from Scilab also has a low level www.simulistics.com