Initializing model

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Jindu
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Initializing model

Post by Jindu » Fri Jun 07, 2019 4:33 pm

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.
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Experiment.mdl
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Administrator
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Re: Initializing model

Post by Administrator » Fri Jun 07, 2019 6:58 pm

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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tomfid
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Re: Initializing model

Post by tomfid » Sun Jun 09, 2019 4:16 am

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).

Jindu
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Re: Initializing model

Post by Jindu » Sun Jun 09, 2019 9:10 pm

Thanks for your reply. I have included the term in desired production but it still does not initialize in a balanced equilibrium.

tomfid
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Re: Initializing model

Post by tomfid » Sun Jun 09, 2019 10:07 pm

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.

Jindu
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Re: Initializing model

Post by Jindu » Mon Jun 10, 2019 8:09 am

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.

tomfid
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Re: Initializing model

Post by tomfid » Mon Jun 10, 2019 1:12 pm

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.

Jindu
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Re: Initializing model

Post by Jindu » Mon Jun 10, 2019 3:31 pm

Thanks. I will try to figure out how to characterize your suggestion.

tomfid
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Re: Initializing model

Post by tomfid » Mon Jun 10, 2019 3:48 pm

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.

Jindu
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Re: Initializing model

Post by Jindu » Tue Jun 11, 2019 7:55 am

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.

Jindu
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Re: Initializing model

Post by Jindu » Thu Jun 13, 2019 10:20 am

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.

tomfid
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Re: Initializing model

Post by tomfid » Thu Jun 13, 2019 4:50 pm

Attachment missing?

Jindu
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Re: Initializing model

Post by Jindu » Fri Jun 14, 2019 8:15 am

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.
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Experiment.mdl
(6.62 KiB) Downloaded 8 times

tomfid
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Re: Initializing model

Post by tomfid » Fri Jun 14, 2019 12:15 pm

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 long-term expectation that is responsive to demand, or the demand must be responsive to inventory (e.g., through discount pricing).

Jindu
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Re: Initializing model

Post by Jindu » Fri Jun 14, 2019 4:46 pm

Thanks I really appreciate your help.

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