System Dynamics Models

These models and simulations have been tagged “System Dynamics”.

Related tagsSterman

Based on model discussed by John D. Sterman (p 508) in  All models are wrong: reflections on becoming a systems scientist  (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flo
Based on model discussed by John D. Sterman (p 508) in All models are wrong: reflections on becoming a systems scientist (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flow connection with a connection from Trig. function.  Repeat (A) & (B).
A Conveyor is an infinite order exponential delay.  This insight illustrates how increasing the order of an exponential delay begins to approximate a conveyor.
A Conveyor is an infinite order exponential delay.  This insight illustrates how increasing the order of an exponential delay begins to approximate a conveyor.
 Based on a dialogue on the System Dynamics mailing list regarding the current level of acceptance of   System Dynamics   after it has been promoted for over 40 years I dredged up the following set of influences as a thought exercise. This is an example of a   Drifting Goals Systems Archetype  .

Based on a dialogue on the System Dynamics mailing list regarding the current level of acceptance of System Dynamics after it has been promoted for over 40 years I dredged up the following set of influences as a thought exercise. This is an example of a Drifting Goals Systems Archetype.

This model (starting with a clone of a previous project on squirrels, mountain lions, and hunters) is a simplified version using only rabbits and snakes.    By modifying the birth and death rates, the variations in population change dramatically. Interestingly, in this iteration, the populations rea
This model (starting with a clone of a previous project on squirrels, mountain lions, and hunters) is a simplified version using only rabbits and snakes.

By modifying the birth and death rates, the variations in population change dramatically. Interestingly, in this iteration, the populations reach dismal lows, but always pick up later. 
11 months ago
Based on model discussed by John D. Sterman (p 508) in  All models are wrong: reflections on becoming a systems scientist  (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flo
Based on model discussed by John D. Sterman (p 508) in All models are wrong: reflections on becoming a systems scientist (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flow connection with a connection from Trig. function.  Repeat (A) & (B).
A new archetype, The Tyranny of Small Steps (TYST) has been observed. Explained through a system dynamics perspective, the archetypical behaviour TYST is an unwanted change to a system through a series of small activities that may be independent from one another. These activities are small enough no
A new archetype, The Tyranny of Small Steps (TYST) has been observed. Explained through a system dynamics perspective, the archetypical behaviour TYST is an unwanted change to a system through a series of small activities that may be independent from one another. These activities are small enough not to be detected by the ‘surveillance’ within the system, but significant enough to encroach upon the “tolerance” zone of the system and compromise the integrity of the system. TYST is an unintentional process that is experienced within the system and made possible by the lack of transparency between an overarching level and a local level where the encroachment is taking place.

Reference:

Haraldsson, H. V., Sverdrup, H. U., Belyazid, S., Holmqvist, J. and Gramstad, R. C. J. (2008), The Tyranny of Small Steps: a reoccurring behaviour in management. Syst. Res., 25: 25–43. doi: 10.1002/sres.859 

Based on model discussed by John D. Sterman (p 508) in  All models are wrong: reflections on becoming a systems scientist  (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flo
Based on model discussed by John D. Sterman (p 508) in All models are wrong: reflections on becoming a systems scientist (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flow connection with a connection from Trig. function.  Repeat (A) & (B).
A model that shows how the digital advertising market is growing and how Google's share in this market, and subsequently their financial results, are influenced by investing in either three of the policy variables.
A model that shows how the digital advertising market is growing and how Google's share in this market, and subsequently their financial results, are influenced by investing in either three of the policy variables.
A new archetype, The Tyranny of Small Steps (TYST) has been observed. Explained through a system dynamics perspective, the archetypical behaviour TYST is an unwanted change to a system through a series of small activities that may be independent from one another. These activities are small enough no
A new archetype, The Tyranny of Small Steps (TYST) has been observed. Explained through a system dynamics perspective, the archetypical behaviour TYST is an unwanted change to a system through a series of small activities that may be independent from one another. These activities are small enough not to be detected by the ‘surveillance’ within the system, but significant enough to encroach upon the “tolerance” zone of the system and compromise the integrity of the system. TYST is an unintentional process that is experienced within the system and made possible by the lack of transparency between an overarching level and a local level where the encroachment is taking place.

Reference:

Haraldsson, H. V., Sverdrup, H. U., Belyazid, S., Holmqvist, J. and Gramstad, R. C. J. (2008), The Tyranny of Small Steps: a reoccurring behaviour in management. Syst. Res., 25: 25–43. doi: 10.1002/sres.859 

 Based on a dialogue on the System Dynamics mailing list regarding the current level of acceptance of   System Dynamics   after it has been promoted for over 40 years I dredged up the following set of influences as a thought exercise. This is an example of a   Drifting Goals Systems Archetype  .

Based on a dialogue on the System Dynamics mailing list regarding the current level of acceptance of System Dynamics after it has been promoted for over 40 years I dredged up the following set of influences as a thought exercise. This is an example of a Drifting Goals Systems Archetype.

Based on model discussed by John D. Sterman (p 508) in  All models are wrong: reflections on becoming a systems scientist  (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flo
Based on model discussed by John D. Sterman (p 508) in All models are wrong: reflections on becoming a systems scientist (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flow connection with a connection from Trig. function.  Repeat (A) & (B).
  Overview  A model which simulates the competition between logging versus adventure tourism (mountain bike ridding) in Derby Tasmania.  Simulation borrowed from the Easter Island simulation.     How the model works.   Trees grow, we cut them down because of demand for Timber amd sell the logs.  Wit
Overview
A model which simulates the competition between logging versus adventure tourism (mountain bike ridding) in Derby Tasmania.  Simulation borrowed from the Easter Island simulation.

How the model works.
Trees grow, we cut them down because of demand for Timber amd sell the logs.
With mountain bkie visits.  This depends on past experience and recommendations.  Past experience and recommendations depends on Scenery number of trees compared to visitor and Adventure number of trees and users.  Park capacity limits the number of users.  
Interesting insights
It seems that high logging does not deter mountain biking.  By reducing park capacity, visitor experience and numbers are improved.  A major problem is that any success with the mountain bike park leads to an explosion in visitor numbers.  Also a high price of timber is needed to balance popularity of the park. It seems also that only a narrow corridor is needed for mountain biking
Based on model discussed by John D. Sterman (p 508) in  All models are wrong: reflections on becoming a systems scientist  (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flo
Based on model discussed by John D. Sterman (p 508) in All models are wrong: reflections on becoming a systems scientist (2002). Task: (A) Sketch what you think the resultant graph will be (see directions for drawing in model). (B) Then Run Simulation.  Optional Extension: Replace Graph In/Out Flow connection with a connection from Trig. function.  Repeat (A) & (B).
A System Dymanic Model of a Predator-Prey interactions using the real-life data. The predator on this model is Equatorial Spitting Cobra while the prey is Palawan Mountain Rat
A System Dymanic Model of a Predator-Prey interactions using the real-life data. The predator on this model is Equatorial Spitting Cobra while the prey is Palawan Mountain Rat
 Visão geral 

 O modelo mostra a
conexão e o conflito da indústria entre o turismo florestal e o turismo de
montanha em Derby, Tasmânia. O objetivo desta simulação é descobrir o ponto de
equilíbrio para a coexistência. 

 Como funciona o
modelo? 

 Ambas as
indústrias podem fornecer contribuições e

Visão geral

O modelo mostra a conexão e o conflito da indústria entre o turismo florestal e o turismo de montanha em Derby, Tasmânia. O objetivo desta simulação é descobrir o ponto de equilíbrio para a coexistência.

Como funciona o modelo?

Ambas as indústrias podem fornecer contribuições económicas para a Tasmânia. Em primeiro lugar, a venda de madeira através da exploração madeireira geraria renda. Além disso, os gastos dos ciclistas de montanha gerariam renda. No entanto, a baixa taxa de regeneração das árvores não pode encobrir a exploração madeireira, o que influencia as belas vistas e as experiências dos ciclistas. Embora a satisfação e a expectativa dependam das opiniões e da experiência, a demanda pelo mountain bike também seria influenciada pelas visitas repetidas e pelo boca a boca.

Informações interessantes

Embora a silvicultura possa fornecer uma grande contribuição económica para a Tasmânia, o excesso de exploração madeireira vai contra a estrutura ESG, além de criar conflito com o turismo de montanha. Desde que o número de visitas de cavaleiros seja estável, o turismo pode sempre proporcionar uma maior contribuição económica em comparação com a silvicultura. Portanto, o governo deveria considerar o ponto de equilíbrio entre as duas indústrias.

7 months ago
 
			 
				 
					  Physician Workforce Model    Modelo baseado na Figura 1 do paper " Forecasting the need for medical specialists in Spain: application of a system dynamics model " (*) de Patricia Barber (**), Beatriz González López-Valcárcel.   (*)  https://human-resources-health.biomedcentral

Physician Workforce Model

Modelo baseado na Figura 1 do paper "Forecasting the need for medical specialists in Spain: application of a system dynamics model" (*) de Patricia Barber (**), Beatriz González López-Valcárcel.

(*) https://human-resources-health.biomedcentral.com/articles/10.1186/1478-4491-8-24

(**) pbarber@dmc.ulpgc.es - University of Las Palmas de Gran Canaria, Campus Universitario de Tafira, 35017 Las Palmas de G.C., Canary Islands, Spain

Virusausbreitung von Covis-19 in Deutschland
Virusausbreitung von Covis-19 in Deutschland
  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