help on hubbert peak.....coding...

[gunpowder]

I was trying to figure out the hubbert peak for coal of australia. And thank god i have figured out quite

well.

Now i am tring to do some sensitivity analysis. I have imposed two conditions.

one condition is on brown coal is that, i have got the data for brown coal for year 1960 - 2007. Then

i thought to reduce the use of brown coal by 40% by the year 2015 and from 2015 afterwards i want to

erase the use of brown coal permanantly. That means from 2007-2015 i will reduce by 40% and then from

2016 i will stop using brown coal.



and 2nd condition is, for black coal. Similarly i have got the data fopr 1960-2007. then i thought to

reduce the use of black coal by 40% by the year 2015 and then from 2016 to onwards the amount will be

same as of 2015th year.


for this i drew this diagram. And for brown coal and brown coal i have written the following code.

brown coal code:

IF THEN ELSE(Time<=2007,actual brown coal,IF THEN ELSE (Time>2007:AND:Time<2015,actual brown coal*(1*"policy of 60% of coal")^(Time-2007),actual brown coal*erase brown coal policy))

in this coding, i guess it is alright. But i am little bit confused about the value of policy of 60%

coal. What would be the value in here?


and for black coal code:


IF THEN ELSE(Time<=2007,actual black coal,IF THEN ELSE(Time>2007:AND:Time<2015,actual black coal*(1*"policy of 60% of coal")^(Time-2007),(actual black coal)))


if anyone can help me on solving this coding, i will highly appreciate this purpose and i will put

his/her name on my paper.

i am waiting for the reply.

[gunpowder]

anyone to help on this topic plz....

[LAUJJL]

Hi

I would use :
IF THEN ELSE(Time<=2007,actual black coal,IF THEN ELSE(Time>2007:AND:Time<2015,actual black coal*"policy of 60% of coal",actual black coal)) with "policy of 60% of coal" = 0.6.
I do not see what the ^(time-2007) is for, nor the 1* “policy...” that can be replaced by “policy...” alone.
It is better to post the full Vensim model.
Regards.
JJ

[gunpowder]

hey thanks for the reply.

according to your suggestion i have done the coding now and it came out with output. i have uploaded the full program file.

I have also attached the output file wave shape for black coal, but i wanted to represent something different. Look the data for 1960-2007 is given, then from 2007-2014 the values are 60% of 2007's value. After that i.e. from 2015 i want to remain constant the value of 2014, not the value of 2007.

please advice me for that what should i do. What will be the black coal coding for that?


one more thing, i have done some sensitivity analysis, and i ploted 3graphs at a same time in one scale. But the numberings are coming in odd numbers, like 1,3,5.

How can i make them like 1,2,3 ??

the answers for these questions will be highly appreciated..

cheers

Sabuj

[LAUJJL]

Hi

I generally ask for a model, because there is an 80% chance that the model does not respect unit checking. How do you expect to build a model without respecting unit dimension checking?
Not respecting unit dimension checking shows that you have not really understood what SD is about.

I am not an academic but a business man near reality. But respecting unit checking (not adding apples to oranges) like mass balance, are the few basic principles that must be understood and always used.

So study the Vensim user guide and its examples and search the Vensim documentation with the keyword ‘unit’.

Regards.

JJ

[gunpowder]

thanks a lot for figured put my mistake. And i had really over looked the one. that one was a great mistake from my side.

i have figured that now. Thats true that an apple cant be added with the orange.

Now please help me on the above problem. I am struggling to write the coding now.

thanks

[LAUJJL]

Hi

I cannot help you if I do not know what you want to do.

One solution would be first to simplify the reality that you want to describe so that it can be described with one short phrase of no more than 10 words.

Than to write the diagram and then the model equivalent with your short definition.

Than to understand your first model and after you have understood fully that first model using all the tools available (what Vensim version do you use?) add some more stuff with care and start again the process.

Regards.

JJ

[gunpowder]

edited

[gunpowder]

ohh sorry i am using 5.10e version of vensim. the free one from the web.

[LAUJJL]

Hi
Use ^((Time – start time) / (time period)). The exponential must be dimensionless (DMNL)
With start time = 2007 (unit year) and time period = your choice (example 1) (unit year)
Regards.
JJ