Hello Everyone,
I am using system dynamics method to study the dynamics of inventory. I replicate the policy structure of inventory and production model. I cannot prevent negative stock of both inventory and the Max statement does not help. The formulation of expected order (Smooth forecast) seem not to be correct It is hard to describe completely the problem in this message. I have attached the model to those who may want to play with it (correct the equation of the forecast).
Please help. I very much appreciate your comment or suggestion.
I look forward to hearing your advice.
I think if you fix the unit errors, what will show up some of the issues. For example, production rate is a delay of the inventory (not the "production start rate").
Hello,
Thanks for your suggestion that was helpful. The other problem is I am finding it really hard to correctly input the equation of the expected order rate stock (smooth forecast) as it doesn’t simulate but brings up an error of simultaneous initial value involving expected order rate. I have attached the model. I would very much appreciate your comment or suggestion.
I look forward to hearing your advice.
Regards.
You need to correct the obvious errors before going any further, get the model to pass the units check and it will show you where things are not right.
Conceptually I think things are a little wrong as well. I'd suggest that "expected order rate" should depend on the "desired inventory", "work in progress inventory" and "expected orders". But you've only got it as a smooth of the "customer order rate".
Administrator wrote: ↑Mon Mar 25, 2019 1:34 pm
You need to correct the obvious errors before going any further, get the model to pass the units check and it will show you where things are not right.
Conceptually I think things are a little wrong as well. I'd suggest that "expected order rate" should depend on the "desired inventory", "work in progress inventory" and "expected orders". But you've only got it as a smooth of the "customer order rate".
Thanks for your reply.
I don’t understand your second statement as I have been trying to figure out what you’ve suggested but I still cannot. I would appreciate it if you could do the changes (expected order rate) on the model I uploaded previously.
Thanks and looking forward to hearing from you.
