From Jay Forrester 1988 killian lectures youtube  video  describing system dynamics at MIT. For Concepts See  IM-185226 . For more detailed biography See Jay Forrester memorial  webpage  For MIT HIstory see  IM-184930
From Jay Forrester 1988 killian lectures youtube video describing system dynamics at MIT. For Concepts See IM-185226. For more detailed biography See Jay Forrester memorial webpage For MIT HIstory see IM-184930
 Regulation of resource allocation to production in response to inventory adequacy and delivery delay. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

Regulation of resource allocation to production in response to inventory adequacy and delivery delay. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

This is a toy model of an investment market.    Households follow a simple ratio to invest in bonds or equities.  In part, the investment decision is stochastic, such that stock market returns are volatile, with equities more volatile than bonds and with a higher yield. As such, the system shows inc
This is a toy model of an investment market.

Households follow a simple ratio to invest in bonds or equities.  In part, the investment decision is stochastic, such that stock market returns are volatile, with equities more volatile than bonds and with a higher yield. As such, the system shows increasing volatility as the investment bubble grows.


 Goodwin cycle  IM-2010  with debt and taxes added, modified from Steve Keen's illustration of Hyman Minsky's Financial Instability Hypothesis "stability begets instability". This can be extended by adding the Ponzi effect of borrowing for speculative investment.

Goodwin cycle IM-2010 with debt and taxes added, modified from Steve Keen's illustration of Hyman Minsky's Financial Instability Hypothesis "stability begets instability". This can be extended by adding the Ponzi effect of borrowing for speculative investment.

  Goodwin Model:   This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013),  Money and Macroeconomic Dynamics , Chapter 4.5 ( link )     Equilibrium conditions:   Labor Supply  = 100  Devation from the equilibrium conditions generates growth cycles.
Goodwin Model:
This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013), Money and Macroeconomic Dynamics, Chapter 4.5 (link)

Equilibrium conditions:
  • Labor Supply = 100
Devation from the equilibrium conditions generates growth cycles.
Clone of Pesticide Use in Central America for Lab work        This model is an attempt to simulate what is commonly referred to as the “pesticide treadmill” in agriculture and how it played out in the cotton industry in Central America after the Second World War until around the 1990s.     The cotto
Clone of Pesticide Use in Central America for Lab work


This model is an attempt to simulate what is commonly referred to as the “pesticide treadmill” in agriculture and how it played out in the cotton industry in Central America after the Second World War until around the 1990s.

The cotton industry expanded dramatically in Central America after WW2, increasing from 20,000 hectares to 463,000 in the late 1970s. This expansion was accompanied by a huge increase in industrial pesticide application which would eventually become the downfall of the industry.

The primary pest for cotton production, bol weevil, became increasingly resistant to chemical pesticides as they were applied each year. The application of pesticides also caused new pests to appear, such as leafworms, cotton aphids and whitefly, which in turn further fuelled increased application of pesticides. 

The treadmill resulted in massive increases in pesticide applications: in the early years they were only applied a few times per season, but this application rose to up to 40 applications per season by the 1970s; accounting for over 50% of the costs of production in some regions. 

The skyrocketing costs associated with increasing pesticide use were one of the key factors that led to the dramatic decline of the cotton industry in Central America: decreasing from its peak in the 1970s to less than 100,000 hectares in the 1990s. “In its wake, economic ruin and environmental devastation were left” as once thriving towns became ghost towns, and once fertile soils were wasted, eroded and abandoned (Lappe, 1998). 

Sources: Douglas L. Murray (1994), Cultivating Crisis: The Human Cost of Pesticides in Latin America, pp35-41; Francis Moore Lappe et al (1998), World Hunger: 12 Myths, 2nd Edition, pp54-55.

 On the occasion of th G20-meeting in Toronto, the German Economics minister Herr Schaüble said that without restoring confidence it would not be possible to get consumer spending and business investment going. Similar remarks were made by David Cameron and Señor Zapatero of Spain. All maintain that

On the occasion of th G20-meeting in Toronto, the German Economics minister Herr Schaüble said that without restoring confidence it would not be possible to get consumer spending and business investment going. Similar remarks were made by David Cameron and Señor Zapatero of Spain. All maintain that confidence is a pre-requisite to get growth going and that, therefore, it was imperative to reduce fiscal deficits. Reducing the fiscal deficit will restore confidence at first. However, reducing the deficit very quickly will introduce a dynamic that may cause the economy to decline - and perhaps depress  consumers demand even further.  It will actually destroy confidence: few businesses are inclined to invest in a shrinking economy. Cutting the deficit too rapidly or too steeply can lead to a confidence trap.

NOTE: A big experiment is now taking place in the UK - the government has cut public spending severely! Will this lead to hardship and, perhaps, social unrest? 

I made this model to simulate how a companies sales will change depending on the lifetime of the appliances it manufactures. It also shows the accumulation of e-waste.
I made this model to simulate how a companies sales will change depending on the lifetime of the appliances it manufactures. It also shows the accumulation of e-waste.
A government deficit means that more money has been transferred in the form of payments or investments from the government sector to the private sector than the government has received in taxes. As shown in the drawing,  GOVERNMENT DEFICIT = INCOME AND SAVING for the private sector. Not all the inco
A government deficit means that more money has been transferred in the form of payments or investments from the government sector to the private sector than the government has received in taxes. As shown in the drawing,  GOVERNMENT DEFICIT = INCOME AND SAVING for the private sector. Not all the income transferred from the government to the private sector will be employed and some of it will be saved in bank accounts. It is therefore correct to say that Government Deficits lead to Private Sector Saving. It is equally true to say that Investment  leads to Saving. This is important because in the current recession one of the major problems is the massive amount of private debt. In these circumstances a cumulative government deficit is necessary to help the private sector save and repay some of its debt. Note: I have not taken into account the foreign sector here which can also contribute to private sector income and saving.
Simulating Hyperinflation for 3650 days.  If private bond holdings are going down and the government is running a big deficit then the central bank has to monetize bonds equal to the deficit plus the decrease in private bond holdings.  We don't show the details of the central bank buying bonds here,
Simulating Hyperinflation for 3650 days.

If private bond holdings are going down and the government is running a big deficit then the central bank has to monetize bonds equal to the deficit plus the decrease in private bond holdings.  We don't show the details of the central bank buying bonds here, just the net results.

See blog at http://howfiatdies.blogspot.com for more on hyperinflation, including a hyperinflation FAQ.
Investigations into the relationships responsible for the success and failure of nations. This investigation was prompted after reading numerous references on the subject and perceiving that *Why Nations Fail: The Origins of Power, Prosperity, and Poverty* by Acemoglu and Robinson seem to make a gre
Investigations into the relationships responsible for the success and failure of nations. This investigation was prompted after reading numerous references on the subject and perceiving that *Why Nations Fail: The Origins of Power, Prosperity, and Poverty* by Acemoglu and Robinson seem to make a great deal of sense.
  Goodwin Model:   This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013),  Money and Macroeconomic Dynamics , Chapter 4.5 ( link )     Equilibrium conditions:   Labor Supply  = 100  Devation from the equilibrium conditions generates growth cycles.
Goodwin Model:
This is a basic version of the Goodwin Model based on Kaoru Yamagushi (2013), Money and Macroeconomic Dynamics, Chapter 4.5 (link)

Equilibrium conditions:
  • Labor Supply = 100
Devation from the equilibrium conditions generates growth cycles.
 Se realiza un diagnóstico de los modelos de gestión de conocimiento que realiza las empresas de desarrollo de software en la ciudad de Medellin, Colombia.     ¿Qué importancia tiene la GC en los procesos de desarrollo de software?  La ingeniería de software es un área en constante evolución, que se
Se realiza un diagnóstico de los modelos de gestión de conocimiento que realiza las empresas de desarrollo de software en la ciudad de Medellin, Colombia.

¿Qué importancia tiene la GC en los procesos de desarrollo de software?
La ingeniería de software es un área en constante evolución, que se basa en la generación de conocimiento, la investigación, la experiencia teórica y práctica obtenida de las organizaciones, las comunidades y de las personas que brindan sus aportes a este proceso evolutivo. 

This model shows the operation of a simple economy. It demonstrates the effect of changes in the fractional rate of consumption (or the converse the fractional rate of saving.)  In summary, lower rates of consumption (based on production) result in higher rates of production and consumption in the l
This model shows the operation of a simple economy. It demonstrates the effect of changes in the fractional rate of consumption (or the converse the fractional rate of saving.)

In summary, lower rates of consumption (based on production) result in higher rates of production and consumption in the long-run.
  Overview  The model simulates how logging in with tourism(mountain biking) in Derby Tasmania.   How the model works.   Trees grow, loggers cut them in order to sell them because of demand for Timber.  Mountain cyclist depends on satisfaction and expectation.  Satisfaction and Expectation depends o
Overview
The model simulates how logging in with tourism(mountain biking) in Derby Tasmania.
How the model works.
Trees grow, loggers cut them in order to sell them because of demand for Timber.
Mountain cyclist depends on satisfaction and expectation.  Satisfaction and Expectation depends on Scenery number of trees compared to visitor and Adventure number of trees and users.  Park capacity limits the number of users.  Local Business is influenced by the timber and number of Mountain Cyclist. Employment is influenced by the number of mountain cyclist and logging activity.

Sandbox for testing InsightMaker features using pipeline Construction & ROW land conversion as a driver of changes in ecosystem service value.
Sandbox for testing InsightMaker features using pipeline Construction & ROW land conversion as a driver of changes in ecosystem service value.
 Regulation of resource allocation to service in response to service quality. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

Regulation of resource allocation to service in response to service quality. A non-price-mediated resource allocation system. From Sterman JD Business Dynamics p172 Fig 5-27

  Format: Given  pre-conditions  when  independent variables(s)  then  dependent variable         Given  Earnings Decline (0.25), Spending Variance (55), Initial Investment (500) and Rate of Return (RandNormal(0.06, 0.12))  when  one of these independent variables change  then  how   sensitive   is
Format: Given pre-conditions when independent variables(s) then dependent variable

Given Earnings Decline (0.25), Spending Variance (55), Initial Investment (500) and Rate of Return (RandNormal(0.06, 0.12)) when one of these independent variables change then how sensitive is Investment (22) over a 30 year time period (-1,000)

H1: if you Earn more then Investment will last much longer => rejected

H2: if you Spend less then Investment will last much longer => accepted

H3: if your Initial Investment is higher then Investment will last much longer => accepted

H4: if you reduce your Spend when Investments are declining then Investment will last much longer => accepted

Given Earnings Decline (0.25), Spending Variance (55), Initial Investment (500) and Rate of Return (RandNormal(0.06, 0.12)) when one of these independent variables are optimised then Investment will last exactly 30 years by minimising the absolute investment gap

H1: if you set an appropriate Spending Base then remaining Investment is 0 => rejected

H2: if you set an appropriate Spending Reduction then remaining Investment is 0 => rejected

Source for investment returns: https://seekingalpha.com/article/3896226-90-year-history-of-capital-market-returns-and-risks
This model shows the structure and operation of a simple economy. It can represent economic systems at different levels of abstraction (e.g. a single good, a group of goods, multiple groups, & an "economy.")  In summary, lower rates of consumption (based on production) result in higher rates of
This model shows the structure and operation of a simple economy. It can represent economic systems at different levels of abstraction (e.g. a single good, a group of goods, multiple groups, & an "economy.")

In summary, lower rates of consumption (based on production) result in higher rates of production and consumption in the long-run. Rates of consumption over 100% of production will diminish the savings stock and eventually cause rates of production and consumption to fall.
Book Summary of The Great Transformation by Karl Polanyi see  Wikipedia  . See also more Karl Polanyi ideas  IM-181325
Book Summary of The Great Transformation by Karl Polanyi see Wikipedia . See also more Karl Polanyi ideas IM-181325
 Cutbacks can have a counterintuitive effect. The government knows precisely how much it custs in spending. However, it cannot know the extent to which tax revenues shrink in a non-linear complex economic system as the economy contracts. In addition, the treasury has to spend more as automatic stabi

Cutbacks can have a counterintuitive effect. The government knows precisely how much it custs in spending. However, it cannot know the extent to which tax revenues shrink in a non-linear complex economic system as the economy contracts. In addition, the treasury has to spend more as automatic stabilizers activate and payments are made to an increasing number of unemployed workers. The effect of this is that initially the deficit shrinks, but later it rises as tax revenues fall short of expectations and more spending takes place. The ironic part is that often the very indicator that promted austerity measurs, the defcit to GDP ratio, becomes worse than it was at the outset. We could observe this in Spain and Portugal where planned deficits have been repeatedly missed, as austerity measures  (fiscal cutbacks) were introduced to deal with the effects of  the 2008 financial crisis.