Inventory or reliability models?

Does any one know how to build a simulation model for an Inventory? Ex: Standard Newspaper problem.
A newsstand buys the papers for 33 cents each and sells them for 50 cents each. Newspapers not sold at the end of the day are sold as scrap for 5 cents each. Newspapers can be purchased in bundles of 10 i., 50, 60, 70 & so on. There are three types of newsdays: "good", "fair", and "poor" and they have the probabilities 0.35, 0.45 and 0.20 respectively.
The distribution of newspapers demanded on each of these days is:


Demand Probability Distribution

Demand Good Fair Poor

40 0.03 0.10 0.44
50 0.05 0.18 0.22
60 0.15 0.40 0.16
70 0.20 0.20 0.12
80 0.35 0.08 0.06
90 0.15 0.04 0.00
100 0.07 0.00 0.00

The problem is to compute the optimal number of papers the newsstand should purchase by simulating demands for 20 days and recording profits from sales each day. The profits are given by

Profit = revenue from sales - cost of newspapers - lost profit from excess demand + salvage from sale of scrap papers

How to make a model for this kind of problem?

Are there any models built on inventory or reliability in Flexsim?

any suggestions or help???

Plz help me out???

Shivrash,

I am not sure, what you expect here from the Forum.

Why do you not just build the model?
Use e.g. a Global Table for your stock, which are just information.
Use a UserEvent (OnReset) to Init your stock.
Use a UserEvent at the end of each day (repeat) to calculate the new stock, profit, etc.
That's in my eyes your model. So you don't need objects, but information and events.
You also could use a few objects to have events and maybe to show the stock level (Visual Tools).
So in general you just manipulte data through events.

Models which go in your direction are SupplyChain Models, because they normally also handle stock. So maybe this model gives you some hints:

http://www.flexsim.com/community/for...do=file&id=203

Originally Posted by Tom David

Shivrash,

I am not sure, what you expect here from the Forum.

Why do you not just build the model?
Use e.g. a Global Table for your stock, which are just information.
Use a UserEvent (OnReset) to Init your stock.
Use a UserEvent at the end of each day (repeat) to calculate the new stock, profit, etc.
That's in my eyes your model. So you don't need objects, but information and events.
You also could use a few objects to have events and maybe to show the stock level (Visual Tools).
So in general you just manipulte data through events.

Models which go in your direction are SupplyChain Models, because they normally also handle stock. So maybe this model gives you some hints:

http://www.flexsim.com/community/for...do=file&id=203

THANX TOM


" So you don't need objects, but information and events.
You also could use a few objects to have events and maybe to show the stock level (Visual Tools).
So in general you just manipulte data through events."

This is what I expected ... Thanx.
I can surely build the model but had doubts about the use of objects....

ne ways, your suggestion has helped me a lot.. thanx