Urban model (trivial example)

Model : edinburgh1
Simile version : 3.1+
Date added : 2003-06-20
Keywords : Urban modelling ; Basic System Dynamics ;

Description

This (entirely hypothetical model) aims to demonstrate the potential for developing urban policy simulators.

The model contains a number of stocks (industrial capital, population size and landfill), and a number of policy levers that the user can manipulate (road pricing and a rubbish uplift charge).

Models like this, expanded and calibrated for particular cities, can be used in a black-box manner, where stakeholders want to see the consequences of different policies. But the big advantage of a visual modelling approach is that the structure of the model is transparent, so that those stakeholders who want to can contribute to a process of critiquing and refining the model.

Files

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edinburgh1.sml

Diagram

Equations

 Industrial capital = 1000
 Landfill = 1000000
 Population size = 500000

        Closures = 10
        Construction = graph(road_pricing)
        Decomposition = 0.2*landfill 
        Mortality = 9000
        Refuse collection = graph(uplift_charge)*population_size 
        Reproduction = 15000

    Age structure = 1
    Cars per head = graph(road_pricing)
    CO2 = 0.5*emissions+100*industrial_capital+0.5*decomposition     Emissions = 1.0e-006*total_cars 
    Health = temperature*age_structure*graph(pollution)
Note: temperature and age_structure are (at this stage) 0-1 multipliers that cause the effect of pollution to be even worse if either is suboptimal
    Pollution = emissions*graph(wind)
    Road pricing = 0
    Temperature = 1
    Total cars = cars_per_head*population_size 
    Uplift charge = 0
    Wind = 2

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