discussing the Urban model from the last SD review

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discussing the Urban model from the last SD review

Postby Jean-Jacques Lauble » Fri Mar 25, 2011 12:14 pm

Hi everybody.

Is there anybody interested by analyzing the simple urban model published in the last SD review?

The model is available by downloading it from the Wiley web site apparently only for SDS member.
I do not know if I can upload the model and make it public.

This model has some peculiarities. For instance if there is an epidemic at time 30 and half of the population dies during a quarter (death rate = 2 during a quarter), the population steps from 271000 to 138000 and the housing construction steps from 2800 to 1300 structures/year and from there starts growing again. After such an event, there is no need to construct anything from quite a long time.

If the population vanishes totally at time 30 (death rate = 4 during a quarter) the population steps from 271000 to 2400 and the Housing construction steps from 2800 to 700 structures/year and from there starts growing again.

The business construction behaves a bit better but there is still apparently too much construction after an epidemic and a complete population death.

These peculiarities may be suppressed by correcting some lookup tables.

The apparently strange behavior coming from an increase of jobs comes necessarily from the fact that the labor participation fraction is kept stable during the 150 years of the simulation and the only way that the model can adjust is by increasing the immigration which is evident.
Apparently the labor participation fraction should be endogenous and adapt itself from the labor to Force ratio.

It seems too possible to avoid the large number of lookup tables which will be difficult to calibrate by replacing the loops with effects by loops with an adjustment time or an adjustment factor that will be much easier to calibrate.

Best regards.
Jean-Jacques Laublé.
Jean-Jacques Lauble
 

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