Modelling Birth Rate to be a variable with time

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raja1978
Junior Member
Posts: 2
Joined: Mon Jan 28, 2019 8:37 pm
Vensim version: PLE

Modelling Birth Rate to be a variable with time

Post by raja1978 »

Hi,

I am a new user of Vensim. I would like to model Birth rate to be a variable type with time as we model in stella. Image file attached.

Similar to the below one:

Population(t) = Population(t - dt) + (Births) * dt
INIT Population = 1000
INFLOWS:
Births = Population*Birth_Rate
Birth_Rate = GRAPH(TIME)
(2016, 0.0802), (2017, 0.0849), (2019, 0.0894), (2020, 0.0939), (2022, 0.0986), (2023, 0.103), (2024, 0.108), (2026, 0.113), (2027, 0.118), (2029, 0.123), (2030, 0.127)

Can someone help me in modelling this in vensim. I am also confused on how to do this using lookup variable type.
Attachments
Birth Rate Variable.jpg
Birth Rate Variable.jpg (76.97 KiB) Viewed 2371 times
Administrator
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Posts: 4573
Joined: Wed Mar 05, 2003 3:10 am

Re: Modelling Birth Rate to be a variable with time

Post by Administrator »

It might be best if you visit the following page as they have a really good PLE tutorial. It will teach you all you need to do this.
http://www.public.asu.edu/~kirkwood/sysdyn/SDRes.htm
Advice to posters seeking help (it really helps us to help you)
http://www.ventanasystems.co.uk/forum/v ... f=2&t=4391

Units are important!
http://www.bbc.co.uk/news/magazine-27509559
raja1978
Junior Member
Posts: 2
Joined: Mon Jan 28, 2019 8:37 pm
Vensim version: PLE

Re: Modelling Birth Rate to be a variable with time

Post by raja1978 »

Thanks. I got to know how to do from one of your links. "Vensim PLE Quick Reference and Tutorial". Time has to be shadow variable.
tomfid
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Joined: Wed May 24, 2006 4:54 am

Re: Modelling Birth Rate to be a variable with time

Post by tomfid »

tomfid
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Re: Modelling Birth Rate to be a variable with time

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