QUERY Age of material in a stock (SD6398)

[SDMAIL Richard Dudley]

Posted by  Richard Dudley <richard.dudley at attglobal.net>

Little's law can tell us about the length of time material is in a stock
when the stock is in equilibrium.
 
Is there any way to _estimate_ the the length of time material is in a stock
when that stock is not in equilibrium?   Or is this a complete unknown?

[ For those who don't recognize it - as I didn't - Little's law is simply    

  stock = average delivery delay * inflow 

  which I tend to think of as Jay's formulation that

  average delivery delay = stock / outflow

  where outflow = inflow in steady state. Jay's formulation is always
  exactly true if the underlying delay distribution is exponential 
  (outflow = level/delay) - if not then only in equilibrium just like 
  Little's Law.]
 
Richard
 
____________________________
 
       Richard G. DudleyPosted by  Richard Dudley <richard.dudley at attglobal.net>
posting date  Fri, 13 Apr 2007 14:20:06 +0700