WOLFRAM SYSTEM MODELER
Population_DynamicsPopulation dynamics |
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Diagram
Wolfram Language
In[1]:=
SystemModel["SystemDynamics.WorldDynamics.World3.Population_Dynamics"]
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Information
This model describes the population dynamics of the WORLD3 model. Whereas the earlier WORLD2 model had lumped all of the population together into a single state variable, WORLD3 offers a demographic model that distinguishes between four age groups, those of the children, those of the younger adults representing the child-bearing population, those of the older adults who are still in the work force, and finally, those of the retired population.
Population is measured in numbers of living humans. In accordance with engineering practice, which (arbitrarily) assigns measurement units only to real-valued quantities and not to integer-valued quantities, this model lists the population as dimensionless.
This model is described on p.142 of Dynamics of Growth in a Finite World.
Parameters (7)
| pop1_init |
Value: 650000000.0 Type: Real Description: Initial population 14 years and younger |
|---|---|
| pop2_init |
Value: 700000000.0 Type: Real Description: Initial population 15 to 44 years old |
| pop3_init |
Value: 190000000.0 Type: Real Description: Initial population 45 to 64 years old |
| pop4_init |
Value: 60000000.0 Type: Real Description: Initial population 65 years and older |
| labor_force_partic |
Value: 0.75 Type: Real Description: Percentage of participating labor force |
| reproductive_lifetime |
Value: 30 Type: Real (yr) Description: Reproductive life time |
| t_pop_equil_time |
Value: 4000 Type: Real (yr) Description: Population equilibrium time |
Connectors (4)
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life_expectancy |
Type: MassInPort Description: Average life expectancy of human population |
|---|---|---|
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labor_force |
Type: MassOutPort Description: Total human labor force |
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total_fertility |
Type: MassInPort Description: Average human fertility |
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population |
Type: MassOutPort Description: Population |
Components (39)
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Births |
Type: RRate Description: p.96 of Dynamics of Growth in a Finite World |
|---|---|---|
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source |
Type: Source Description: This is the (dummy) source model of System Dynamics |
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Pop_0_14 |
Type: Level2b Description: General System Dynamics level with two outflows |
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Matur_14 |
Type: RRate Description: p.141 of Dynamics of Growth in a Finite World |
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Pop_15_44 |
Type: Level2b Description: p.57 of Dynamics of Growth in a Finite World |
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Matur_44 |
Type: RRate Description: p.141 of Dynamics of Growth in a Finite World |
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Pop_45_64 |
Type: Level2b Description: p.57 of Dynamics of Growth in a Finite World |
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Matur_64 |
Type: RRate Description: p.141 of Dynamics of Growth in a Finite World |
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Pop_65plus |
Type: Level Description: p.57 of Dynamics of Growth in a Finite World |
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Deaths_65p |
Type: RRate Description: p.57 of Dynamics of Growth in a Finite World |
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sink |
Type: Sink Description: This is the (dummy) sink model of System Dynamics |
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births |
Type: Birth_Factors Description: p.96 of Dynamics of Growth in a Finite World |
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Deaths_0_14 |
Type: RRate Description: p.57 of Dynamics of Growth in a Finite World |
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sink1 |
Type: Sink Description: This is the (dummy) sink model of System Dynamics |
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Deaths_15_44 |
Type: RRate Description: p.57 of Dynamics of Growth in a Finite World |
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sink2 |
Type: Sink Description: This is the (dummy) sink model of System Dynamics |
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Deaths_45_64 |
Type: RRate Description: p.57 of Dynamics of Growth in a Finite World |
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sink3 |
Type: Sink Description: This is the (dummy) sink model of System Dynamics |
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matur_14 |
Type: Matur_Factors Description: p.141 of Dynamics of Growth in a Finite World |
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matur_44 |
Type: Matur_Factors Description: p.141 of Dynamics of Growth in a Finite World |
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matur_64 |
Type: Matur_Factors Description: p.141 of Dynamics of Growth in a Finite World |
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deaths_0_14 |
Type: Death_Factors Description: p.57 of Dynamics of Growth in a Finite World |
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deaths_15_44 |
Type: Death_Factors Description: p.57 of Dynamics of Growth in a Finite World |
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deaths_45_64 |
Type: Death_Factors Description: p.57 of Dynamics of Growth in a Finite World |
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deaths_65p |
Type: Death_Factors Description: p.57 of Dynamics of Growth in a Finite World |
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Mort_0_14 |
Type: Tabular Description: p.57 of Dynamics of Growth in a Finite World |
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Mort_15_44 |
Type: Tabular Description: p.57 of Dynamics of Growth in a Finite World |
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Mort_45_64 |
Type: Tabular Description: p.57 of Dynamics of Growth in a Finite World |
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Mort_65p |
Type: Tabular Description: p.57 of Dynamics of Growth in a Finite World |
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Pop_Young |
Type: Add Description: Output the sum of the two inputs |
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Pop_Old |
Type: Add Description: Output the sum of the two inputs |
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Population |
Type: Add Description: Output the sum of the two inputs |
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Death_Young |
Type: Add Description: Output the sum of the two inputs |
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Death_Old |
Type: Add Description: Output the sum of the two inputs |
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Deaths |
Type: Add Description: Output the sum of the two inputs |
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Work_Pop |
Type: Add Description: p.241 of Dynamics of Growth in a Finite World |
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Labor_Force |
Type: Gain Description: p.241 of Dynamics of Growth in a Finite World |
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Birth_Rate |
Type: BD_Rates Description: p.97 of Dynamics of Growth in a Finite World |
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Death_Rate |
Type: BD_Rates Description: p.140 of Dynamics of Growth in a Finite World |
Used in Examples (11)
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SystemDynamics.WorldDynamics.World3 Original WORLD3 model |
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SystemDynamics.WorldDynamics.World3 More abundant non-recoverable natural resources |
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SystemDynamics.WorldDynamics.World3 More accessible non-recoverable natural resources and pollution control |
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SystemDynamics.WorldDynamics.World3 More accessible non-recoverable natural resources, pollution control, and land yield enhancement |
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SystemDynamics.WorldDynamics.World3 More accessible non-recoverable natural resources, pollution control, land yield enhancement, and erosion protection |
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SystemDynamics.WorldDynamics.World3 More accessible non-recoverable natural resources, pollution control, land yield enhancement, erosion protection, and resource efficiency |
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SystemDynamics.WorldDynamics.World3 More abundant non-recoverable natural resources and birth control |
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SystemDynamics.WorldDynamics.World3 More abundant non-recoverable natural resources, birth control, and stable industrial output |
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SystemDynamics.WorldDynamics.World3 Combining the measures of Scenarios #6 and #8 |
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SystemDynamics.WorldDynamics.World3 Influencing the future 20 years earlier |
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SystemDynamics.WorldDynamics.World3 Influencing the future 10 years later |