From: Mathieu Roy <yeupou(at)gnu.org> [ date: 2003-01-05 ]

There are several critical issues in this text about definitions and methodology.

I made several comments in French at the following addresses (sorry, no time to translate them)

http://linuxfr.org/comments/162184.html

http://linuxfr.org/comments/162185.html

http://linuxfr.org/comments/162191.html

From: Ralf Wieland <rwieland(at)zalf.de> [ date: 2003-01-07 ]

Dear friends,

here are some remarks for my demography model. I want to make a

simple and easy to understand modell. My intention was not a

scientific application. Therefor are some simplifications in

the model. Firstly the birthrate. I use the mean number of

children per woman. This number is easy to understand and it

can be changed by the user. The program calculates the from

this number the actual birthrate. Please forgive this inaccuracy.

I calculate the birthrate by devision with 30 years (for a

the woman of childbearing age in the program 30 years) That is

a simplification because the propability of childbearing differs

of this period. But this simplification is easy to change by changing

the source code. It can be done in the same way how the migration

is splitted. But in our area of interest in North-East-Germany

this propability is changing very fast over the last ten years and

I had no actual statistical dates. So I only used the simple

variant. For the migration it is not better. We have no statistical

data. So I had to estimate the parameters. But it doesn't matter

in future (if we have better dates) it is easy to adapt the parameters.

You see, I'm a programmer not a demograph. I use models to

understand processes in the nature. Of course we have do to

some work before we can use our modell to forecast the development

in our area. But we have connected our dynamic approach with a

spatial fuzzy model to see how we can estimate the migration as

a function of the space. So we done some calculation to see how

a migration can be in space and in time. So far to the intention of

my work.

The demographic model in the article is only a part of my work.

But I hope it is interesting for someone to play with it. If you

want to do some serious calculations with it you can use the

source code an change it to your conditions. It would be nice

is we could speak about it.

regards

Ralf Wieland

2 talkbacks

Due to the increased amount of web spam we have deciced to removed the talkback posting possibility. You can read old talkbacks but you can no longer post new ones.

Please contact webmaster(at)linuxfocus.org if you have any questions with regards to this talkback

lftalkback version 3.10