Search found 21 matches

by Nesli
Wed Aug 26, 2015 4:10 pm
Forum: Vensim
Topic: feedbacks/comments about our waste management model
Replies: 0
Views: 1302

feedbacks/comments about our waste management model

Hello, By using Vensim software, we have built a model regarding healthcare waste management in environmental engineering department. We are now working on the validation of this model and seeking ideas/comments for this model as attached. Is there anyone interested in healthcare waste management an...
by Nesli
Sat Apr 18, 2015 5:17 am
Forum: Vensim
Topic: continuous delay
Replies: 6
Views: 2674

Re: continuous delay

Many thanks..
by Nesli
Fri Apr 17, 2015 4:07 pm
Forum: Vensim
Topic: continuous delay
Replies: 6
Views: 2674

Re: continuous delay

Hello after a long time,

Is there any example on how to use DELAY information functions as a link/file or etc.

I find it confusing to decide which delay function (order of it) to use in my model...

Thanks
by Nesli
Wed May 16, 2012 7:40 pm
Forum: Vensim
Topic: continuous delay
Replies: 6
Views: 2674

continuous delay

Hi, Could anyone please explain how DELAY1 is different than DELAY3 logically?..or how can I justify that I use DELAY3 but not DELAY1 in my model?.. I know that DELAY 3 takes it as if there are 3 stocks...I wonder how we decide delay3 is more suitable for our model? Is it because of time step should...
by Nesli
Thu Aug 04, 2011 8:23 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

OK thank you..
by Nesli
Thu Aug 04, 2011 10:49 am
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

Thank you so much for your response.. I exported the sensitivity run to the excel file and traced the values.. When I set D in a range of 0.05-0.45 rather than (0.05-0.20) I have one peak or if I use Random Normal Simulation I have one peak again.. If it is not too many questions can I ask; (1) The ...
by Nesli
Tue Aug 02, 2011 7:32 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

I thought that C should be decreasing as I set a range for Y smaller than its actual value so i thought only E*D could cause an increase for B as I set a range for D bigger than its actual value.. Could you please explain me more about what I think please-I understand your comment for E but how does...
by Nesli
Tue Aug 02, 2011 5:55 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

I managed to attach the bar chart as Jpeg.. It is a histogram for parameter B.. More often, you tend to get a normal type distribution where a single peak displays the most frequently occurring. This clustering around a single value of B and then a distribution of other values with smaller frequenci...
by Nesli
Tue Aug 02, 2011 5:40 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

Could you pls check bar chart histogram for the final time..there are two peak columns..
by Nesli
Tue Aug 02, 2011 5:07 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

Y= RANDOM UNIFORM (1, 1.8 )
by Nesli
Tue Aug 02, 2011 5:05 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

Thank you, I simplified my model and attached. What I want to do is to run a sensitivity test for B by setting these ranges to my two parameters: Y=RANDOM UNIFORM (1,1.8) D= RANDOM UNIFORM (0.05-0.20) Regardless of the number of simulation I have two peaks in histogram (for the final time).. I am wo...
by Nesli
Tue Aug 02, 2011 3:32 pm
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

Re: sensitivity analysis

Thank you, Then it means, for example SALES model (in Vensim Guide) if we set a range for "price of item" (lets say 100-200 random unifrom), we can run sensitivity for cash flow.. When I do so, the histogram for the last time appears with two peak columns (bimodel).. However I know that more often, ...
by Nesli
Tue Aug 02, 2011 10:51 am
Forum: Vensim
Topic: sensitivity analysis
Replies: 15
Views: 2293

sensitivity analysis

Hi, I am using Vensim PLE plus and want to conduct sensitivity analysis for one parameter (C) by setting a range for two parameters (A and B).. However parameters A and B are not in a feedback loop with parameter C..Their relation is like below: C= X+Y*B Y=W*A Can I still use sensitivity analysis to...
by Nesli
Tue Apr 19, 2011 11:19 am
Forum: Vensim
Topic: warnings
Replies: 5
Views: 2155

Re: warnings

Many thanks,
Nesli
by Nesli
Mon Apr 18, 2011 3:43 pm
Forum: Vensim
Topic: warnings
Replies: 5
Views: 2155

Re: warnings

Can I ask one more question,

When I click on units check, it gives another warning that: WARNING: Lookup used with dimensioned argument-Year,

I know I use lookup function dependant on time, so what is the point of this error message?
Thanks again..
by Nesli
Mon Apr 18, 2011 3:02 pm
Forum: Vensim
Topic: warnings
Replies: 5
Views: 2155

Re: warnings

Thank you so much, when i changed the time period, i missed to add the values for the years 20-33 to the Lookup..
Yes it is ok now, many thanks..
nesli
by Nesli
Mon Apr 18, 2011 12:12 pm
Forum: Vensim
Topic: warnings
Replies: 5
Views: 2155

warnings

Hello, I have a question to ask.. I have Look up table in my model dependant on <Time> such as: proportion of municipal waste segregated: segregation training effectivieness(Time) segregation training effectivieness:[(0,0)-(20,10)],(0,1.7),(20,1.7) When I run the model, I see warning like this: WARN...
by Nesli
Mon Mar 07, 2011 9:59 pm
Forum: Vensim
Topic: copy-paste big models to other files
Replies: 1
Views: 742

copy-paste big models to other files

Hello, I have a question about copy/scale/zoom I want to copy and paste my model on an MS Word file as a picture to present the structure and names of the variables involved in the model. The problem is the model itself is big. As i want all the variables to look all together, i dont want to use sep...
by Nesli
Wed Jan 19, 2011 11:53 am
Forum: Vensim
Topic: need help..
Replies: 9
Views: 1608

Re: need help..

JJ and Tom, Many thanks...

I tried to apply your ideas and modified the model (as attached). I hope this time I employed the functions correctly..Any ideas appreciated..

Nesli
by Nesli
Tue Jan 18, 2011 4:55 pm
Forum: Vensim
Topic: need help..
Replies: 9
Views: 1608

Re: need help..

Thank you so much indeed.. Regarding frequencies, I modified them by converting to average time it takes for somebody to be infected/died.. Regarding delays: you were quite right by saying that the sum of 2 outputs exceeds the level, thats why the level goes negative.. I suppose that I cannot use ex...
by Nesli
Tue Jan 18, 2011 12:42 pm
Forum: Vensim
Topic: need help..
Replies: 9
Views: 1608

need help..

Hi, i am doing phd in Leeds University and my topic is related to waste management. I am using Vensim PLE as a method. I built a model (as attached) but having some troubles which is like having Population Stock negative under some certain set of data. Here it is: The aim is to make an estimation on...