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.) It also, unlike Models 2 & 3, shows the influence Savings has on the  production rate .  In summary, lower rates of co
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.) It also, unlike Models 2 & 3, shows the influence Savings has on the production rate.

In summary, lower rates of consumption (based on production) result in higher rates of both production and consumption in the long-run.
The simulation integrates or sums (INTEG) the Nj population, with a change of Delta N in each generation, starting with an initial value of 5. The equation for DeltaN is a version of  Nj+1 = Nj  + mu (1- Nj / Nmax ) Nj  the maximum population is set to be one million, and the growth rate constant mu
The simulation integrates or sums (INTEG) the Nj population, with a change of Delta N in each generation, starting with an initial value of 5.
The equation for DeltaN is a version of 
Nj+1 = Nj  + mu (1- Nj / Nmax ) Nj
the maximum population is set to be one million, and the growth rate constant mu = 3.
 
Nj: is the “number of items” in our current generation.

Delta Nj: is the “change in number of items” as we go from the present generation into the next generation. This is just the number of items born minus the number of items who have died.

mu: is the growth or birth rate parameter, similar to that in the exponential growth and decay model. However, as we extend our model it will no longer be the actual growth rate, but rather just a constant that tends to control the actual growth rate without being directly proportional to it.

F(Nj) = mu(1‐Nj/Nmax): is our model for the effective “growth rate”, a rate that decreases as the number of items approaches the maximum allowed by external factors such as food supply, disease or predation. (You can think of mu as the growth or birth rate in the absence of population pressure from other items.) We write this rate as F(Nj), which is a mathematical way of saying F is affected by the number of items, i.e., “F is a function of Nj”. It combines both growth and all the various environmental constraints on growth into a single function. This is a good approach to modeling; start with something that works (exponential growth) and then modify it incrementally, while still incorporating the working model.

Nj+1 = Nj + Delta Nj : This is a mathematical way to say, “The new number of items equals the old number of items plus the change in number of items”.

Nj/Nmax: is what fraction a population has reached of the maximum "carrying capacity" allowed by the external environment. We use this fraction to change the overall growth rate of the population. In the real world, as well as in our model, it is possible for a population to be greater than the maximum population (which is usually an average of many years), at least for a short period of time. This means that we can expect fluctuations in which Nj/Nmax is greater than 1.

This equation is a form of what is known as the logistic map or equation. It is a map because it "maps'' the population in one year into the population of the next year. It is "logistic'' in the military sense of supplying a population with its needs. It a nonlinear equation because it contains a term proportional to Nj^2 and not just Nj. The logistic map equation is also an example of discrete mathematics. It is discrete because the time variable j assumes just integer values, and consequently the variables Nj+1 and Nj do not change continuously into each other, as would a function N(t). In addition to the variables Nj and j, the equation also contains the two parameters mu, the growth rate, and Nmax, the maximum population. You can think of these as "constants'' whose values are determined from external sources and remain fixed as one year of items gets mapped into the next year. However, as part of viewing the computer as a laboratory in which to experiment, and as part of the scientific process, you should vary the parameters in order to explore how the model reacts to changes in them.
A simple implementation of a Dynamic ISLM model as proposed by Blanchard (1981), and taken from An introduction to economic Dynamics - Shone (1997) - chapter 5. This model might serve as a framework to evaluate economic policies over GDP growth.
A simple implementation of a Dynamic ISLM model as proposed by Blanchard (1981), and taken from An introduction to economic Dynamics - Shone (1997) - chapter 5. This model might serve as a framework to evaluate economic policies over GDP growth.
Simulation of MTBF with controls   F(t) = 1 - e ^ -λt   Where    • F(t) is the probability of failure    • λ is the failure rate in 1/time unit (1/h, for example)   • t is the observed service life (h, for example)  The inverse curve is the trust time On the right the increase in failures brings its
Simulation of MTBF with controls

F(t) = 1 - e ^ -λt 
Where  
• F(t) is the probability of failure  
• λ is the failure rate in 1/time unit (1/h, for example) 
• t is the observed service life (h, for example)

The inverse curve is the trust time
On the right the increase in failures brings its inverse which is loss of trust and move into suspicion and lack of confidence.
This can be seen in strategic social applications with those who put economy before providing the priorities of the basic living infrastructures for all.

This applies to policies and strategic decisions as well as physical equipment.
A) Equipment wears out through friction and preventive maintenance can increase the useful lifetime, 
B) Policies/working practices/guidelines have to be updated to reflect changes in the external environment and eventually be replaced when for instance a population rises too large (constitutional changes are required to keep pace with evolution, e.g. the concepts of the ancient Greeks, 3000 years ago, who based their thoughts on a small population cannot be applied in 2013 except where populations can be contained into productive working communities with balanced profit and loss centers to ensure sustainability)

Early Life
If we follow the slope from the leftmost start to where it begins to flatten out this can be considered the first period. The first period is characterized by a decreasing failure rate. It is what occurs during the “early life” of a population of units. The weaker units fail leaving a population that is more rigorous.

Useful Life
The next period is the flat bottom portion of the graph. It is called the “useful life” period. Failures occur more in a random sequence during this time. It is difficult to predict which failure mode will occur, but the rate of failures is predictable. Notice the constant slope.  

Wearout
The third period begins at the point where the slope begins to increase and extends to the rightmost end of the graph. This is what happens when units become old and begin to fail at an increasing rate. It is called the “wearout” period. 
This is part of series of model implemented from "Thinking in Systems" book by Donella Meadows
This is part of series of model implemented from "Thinking in Systems" book by Donella Meadows
Irving Fisher's Debt Deflation Theory from Michael Joffe Fig. 3.4 p54  Ch3 Feedback Economics Book  with Private Credit Inflation boom added to the  bust cycles
Irving Fisher's Debt Deflation Theory from Michael Joffe Fig. 3.4 p54 Ch3 Feedback Economics Book with Private Credit Inflation boom added to the  bust cycles
From  Political Compass website  showing political economic spectrum of Australian political parties contesting Federal elections in 2007-2022
From Political Compass website showing political economic spectrum of Australian political parties contesting Federal elections in 2007-2022
 Clone of Wagdy Samir Macroeconomics work in progress  IM-901  Additions and deletions based on Robert Skidelsky's description of Keynes general THeory from his Biography Vol2 p 549 -571

Clone of Wagdy Samir Macroeconomics work in progress IM-901 Additions and deletions based on Robert Skidelsky's description of Keynes general THeory from his Biography Vol2 p 549 -571

Graph representation of Ch3 of their 2007 Monetary Economics book, based on Alvarez and Ehnts 2015  paper  The roads not taken. Also see more complex WIP to successively split sectors at  IM-185550  . See also  essence of MMT IM  for simpler intro
Graph representation of Ch3 of their 2007 Monetary Economics book, based on Alvarez and Ehnts 2015 paper The roads not taken. Also see more complex WIP to successively split sectors at IM-185550 . See also essence of MMT IM for simpler intro
Based on the Market and Price simulation model in System Zoo 3. I wrote an explanation of the model which you can find here: https://docs.google.com/document/d/1yRTtZvOOrFiBlK6pkvbpSUv_ajvGMKSAbfthRTBPU-8/edit?usp=sharing 
Based on the Market and Price simulation model in System Zoo 3.
I wrote an explanation of the model which you can find here: https://docs.google.com/document/d/1yRTtZvOOrFiBlK6pkvbpSUv_ajvGMKSAbfthRTBPU-8/edit?usp=sharing 
8 9 months ago
WIP  based on Where profits come from  paper  , Nathan Tankus  blog  and other historical sources
WIP  based on Where profits come from paper , Nathan Tankus blog and other historical sources
Unfortunately, this model only produces the illusion of functioning, but I did manage to get it to give me the graph. However, because of the use of flows, if you change the time step to and the simulation length to anything other than the same numbers, you'll find the graph showing something that l
Unfortunately, this model only produces the illusion of functioning, but I did manage to get it to give me the graph. However, because of the use of flows, if you change the time step to and the simulation length to anything other than the same numbers, you'll find the graph showing something that looks more exponential. This is due to the function referencing itself in regards to time, so inevitably each time consumption grows it changes the outcome on the other side of the equation. Still, this is a convincing mock up. I added a "45 degree" line so that one could conceivably see (and also change) the difference made by altering the level of autonomous consumption.
 IM-168155  Summary of Ch 27 of Mitchell Wray and Watts Textbook see  IM-164967  for book overview with simplified Mike Radzicki's 2003 Evolutionary Economics history  article  added
IM-168155 Summary of Ch 27 of Mitchell Wray and Watts Textbook see IM-164967 for book overview with simplified Mike Radzicki's 2003 Evolutionary Economics history article added
Spending by
the government   creates   its own 'financial resource' as the process of
crediting an account in the private sector takes place. This may sound like
nonsense, but in fact it is 'monetary reality'. This premise is supported by Bell
(1998; 2000) and Wray (1998a) who argue that the Treasur
Spending by the government creates its own 'financial resource' as the process of crediting an account in the private sector takes place. This may sound like nonsense, but in fact it is 'monetary reality'. This premise is supported by Bell (1998; 2000) and Wray (1998a) who argue that the Treasury does not need to collect or borrow funds in order to spend, but crates new funds as it spends.

Perhaps the following thought experiment  helps to understand how this is possible.  

If you imagine two drawers, each representing an account. The first drawer contains 100 gold coins and the second is empty. Also imagine that there are no other gold coins available at this time. Let's call the first drawer account A and the second account B. Now if you want to transfer 30 gold coins from account A to account B, you would actually first have to take the coins out of drawer A and then place them into drawer B. Account A will then necessarily have 30 coins less in it. Now imagine accounts A and B are held in a computer as electronic money. Instead of 100 gold coins, account A only contains the computer generated number '100'  and account B shows '0'. To get account B to show a balance of '30', it would now simple be necessary to change the '0' to '30' on the computer. The need to raid account A and to take '30' from the number '100' before you could credit  account B does not exist. Money is created as it is entered in B's account irrespective of whether A's account is debited before or after this process or not at
WIP based on Bill mitchell's blogs.  Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
WIP based on Bill mitchell's blogs. 
Sectoral balances are relationships among money flows during an accounting period. Where we perceive accumulations of past imbalances to be accrued is another matter....
  This model
shows the basic functioning and dynamics of a 'modern monetary system'.  The non-government
sectors, consisting of the private and foreign sectors initial y starts with
zero currency units. It is important to realize that  after creating a new currency the government
must first spend cu

This model shows the basic functioning and dynamics of a 'modern monetary system'.

The non-government sectors, consisting of the private and foreign sectors initial y starts with zero currency units. It is important to realize that  after creating a new currency the government must first spend currency units into the economy before they can be used: without currency units the private sector could not even pay taxes! A government that has its own freely floating currency can create a much money as it wants. It does not need tax receipts to finance its spending, and any money it spends into the economy above that collected in taxes represents income for the private sector. The model show that the government initially created 9 trillion money units, but spent only six trillion into the economy. The six trillion showed up as a government deficit, but also as wealth in the non-government sector.

Since the government can create as many money units as it wishes and transfer  them  to the private sector  to ensure an adequate level of demand in the in the economy,  austerity is unnecessary: money is available, though real resource may be scarce. This also shows that the government can contribute actively towards the creation of prosperity. 

Please note that this model was originally created by Gene Bellinger, IM 3206, from which this version was  cloned.


There is an old saying that says
that 'opportunity makes thieves'.  But
there is  also a research paper entitled
'Opportunity makes the Thief: Practical Theory of Crime Prevention (1998)' that
provides evidence supporting this common observation. The paper argues that  opportunity is a “root cause”
There is an old saying that says that 'opportunity makes thieves'.  But there is  also a research paper entitled 'Opportunity makes the Thief: Practical Theory of Crime Prevention (1998)' that provides evidence supporting this common observation. The paper argues that  opportunity is a “root cause” of crime. This therefore also applies to the behaviour of corporations.

 

The Causal Loop Diagram on the left indicates that the number of crimes will  increase rapidly as the opportunities to commit them increases.  This suggests that the introduction of a negative feedback loop aimed at diminishing  opportunities for committing crimes is an appropriate measure to improve the situation. A number of remedial mesures  tailored to specific situations are contained in the report. A generally effective means must be the use of law and regulations that were also mentioned in the report.



WIP Overview model structures of Khalid Saeed's 2014  WPI paper  Jay
Forrester’s Disruptive Models of Economic Behavior  See also General SD and Macroeconomics CLDs  IM-168865
WIP Overview model structures of Khalid Saeed's 2014 WPI paper Jay Forrester’s Disruptive Models of Economic Behavior  See also General SD and Macroeconomics CLDs IM-168865
2 months ago
 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

An attempt to combine ideas from Joe Stiglitz's  Book  The Price of Inequality,  Peter Turchin 's  book Secular Cycles  and Khalil Saeed and Oleg Pavlov's Dynastic Cycles SD model  paper
An attempt to combine ideas from Joe Stiglitz's Book The Price of Inequality, Peter Turchin's book Secular Cycles and Khalil Saeed and Oleg Pavlov's Dynastic Cycles SD model paper
Implementation of a DSGE Model solved in a Macroeconomics class by Harald Uhlig ( link ), using Rational Expectations, in this case, the Hansens Real Business Cycle Model. It shows the capacity of implementing Dynamic Stochastic General Equilibrium Model Analysis using System Dynamics.
Implementation of a DSGE Model solved in a Macroeconomics class by Harald Uhlig (link), using Rational Expectations, in this case, the Hansens Real Business Cycle Model.
It shows the capacity of implementing Dynamic Stochastic General Equilibrium Model Analysis using System Dynamics.
WIP Comparing Univeral Basic Income Guarantee with the Job Guarantee based on comparison articles
WIP Comparing Univeral Basic Income Guarantee with the Job Guarantee based on comparison articles
 Wagdy Samir work in progress. Addition of Bill Mitchell's draft textbook  chapter1   See also  The value of everything book IM

Wagdy Samir work in progress. Addition of Bill Mitchell's draft textbook chapter1  See also The value of everything book IM