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Roman Knaus
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.

Environment MATHS Mathematics Chaos Fractals BIFURCATION Model Economics Finance TURBULENCE Population Growth DECAY STABILITY SUSTAINABLE Engineering Science Demographics Strategy

  • 3 years 9 months ago


Ricardo Santana Cabello

The existing global capitalistic growth paradigm is totally flawed

Growth in supply and productivity is a summation of variables as is demand ... when the link between them is broken by catastrophic failure in a component the creation of unpredictable chaotic turbulence puts the controls ito a situation that will never return the system to its initial conditions as it is STIC system (Lorenz)

The chaotic turbulence is the result of the concept of infinite bigness this has been the destructive influence on all empires and now shown up by Feigenbaum numbers and Dunbar numbers for neural netwoirks

See Guy Lakeman Bubble Theory for more details on keeping systems within finite working containers (villages communities)

Environment Economics Finance Mathematics Physics Biology Health Fractals Chaos TURBULENCE Engineering Navier Stokes Supply Demand Strategy

  • 3 years 4 months ago

Fixed rate mortgage deal model

Mark de Cates
Models the repayment of a mortgage, with a fixed-term fixed-rate deal.
e.g. for an up-front £1495 fee, you get a fixed interest rate of 1.22% for 2 years, followed by variable rate).
After the deal ends, the 'variable' rate is currently constant, but could be set via a converter instead to model different predictions of future interest rates. 


  • 1 year 1 month ago

Clone of HODL vs. cloud mining

Simulation compares Bitcoin cloud mining opportunity ( to HODL.The model does not calculate with mining difficulty, pool's efficiency and changes in fees. Using monthly cloud fees as of the end of November 2017.Used for mining calculations.

Finance Bitcoin Crypto

  • 2 years 2 weeks ago

Clone of Bob - Expanded

Chris Magnuson
This is what I would imagine how most of the US's personal finances look: The individual has a retirement account set up or will be getting pensions upon retiring and has replaced his or her rent payment with a mortgage, which will go away after 15-30 years.


  • 5 years 3 months ago

mutual funds savings value overtime (IDR)

Nurul Khairiza Utami
the simulation shows how our money grows overtime as we keep investing our money every month in money market mutual funds. But overtime monetary value keeps growing up with constant rate of 3%, so what this simulation shows us is the real value of the money we invest in mutual funds that have a certain rate of interest.

Finance Growth

  • 8 months 1 week ago