Initializing model
Initializing model
Hi Everyone.
I am trying to initialize the attached model (a push inventory system) in a balanced equilibrium maybe the equation and/or structure is wrong. Please help.
Many thanks.
I am trying to initialize the attached model (a push inventory system) in a balanced equilibrium maybe the equation and/or structure is wrong. Please help.
Many thanks.
 Attachments

 Experiment.mdl
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Re: Initializing model
I'd suggest maybe looking at initialising the levels properly. At t = 0, the work in progress inventory is zero, so you will never start with a steady state.
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Re: Initializing model
I think you've forgotten a term in desired production  currently it only adjusts the inventory level. It also needs to replace inventory losses (sales, or in your case expected orders, I think).
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Re: Initializing model
Thanks for your reply. I have included the term in desired production but it still does not initialize in a balanced equilibrium.
Re: Initializing model
You have the same kind of problem in your Desired Production Start Rate  it adjusts for WIP, but absent a shortage of WIP, it won't produce anything.
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Re: Initializing model
I do understand. However, I am trying to build a PUSH Model  if I follow through your suggestion the model would become a push/pull model. I don't know whether you understand.
Re: Initializing model
I see what you're getting at, but in a push system, there still needs to be an expectation or forecast of sales that governs how much to push.
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Re: Initializing model
Thanks. I will try to figure out how to characterize your suggestion.
Re: Initializing model
You could create something like a "desired push rate" which represents the material to be sent through the chain. Then you'd have to have some kind of flexible policy at the sales end, like pricing and promotion needed to ensure that sales are sufficient to keep inventory from piling up or running short.
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Re: Initializing model
Thank you for your response to my inquiry. I appreciate the information you have provided me with and I appreciate the prompt reply. I just need to think of how to input the equation of the desired push rate.
Re: Initializing model
I have created "desired push rate" as suggested but the model still doesn’t start at equilibrium in the attached (push) model. I guess the information link and/or equations I modeled are incorrect. Please help on how to do this thanks.
Re: Initializing model
Attachment missing?
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Re: Initializing model
Here is the attached push model I am trying to build that does not start in a balanced equilibrium. I guess the information link and/or equations are incorrect I would really appreciate any help to overcome this problem. Thanks.
 Attachments

 Experiment.mdl
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Re: Initializing model
This would be in equilibrium if desired push rate = customer order rate. However, there's no feedback enforcing that. Either the push rate must be based on some longterm expectation that is responsive to demand, or the demand must be responsive to inventory (e.g., through discount pricing).
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Re: Initializing model
Thanks I really appreciate your help.