Author 
Message 
Peter Spellucci science forum Guru
Joined: 29 Apr 2005
Posts: 702

Posted: Thu Jul 13, 2006 11:19 am Post subject:
Re: Logistic timestep problem



In article <1152780168.218894.94870@m79g2000cwm.googlegroups.com>,
christriddle@googlemail.com writes:
Quote:  Hi,
First of all I'm not sure if this belongs here, if not, could you
suggest a more appropriate group.
I'm having some problems researching the possibility of explicit
solutions to military logistics problems.
Although, I think the actual problem is more general. I have a
timestep simulation tool that simulates strategiclift (aircraft,
ships, etc...) moving "stuff" from a start port to an end port.
Obviously aircraft make many flights back and forth.
While a timestep simulation suits this problem, it is quite expensive
in time.
The question I need answering is whether there exists an explicit
solution to such a problem. I'm pretty sure it's not linear, and
perhaps chaotic behaviour prevents such a solution.
By the way, when I say solution I mean things like finding:
a) How long it takes to move everything with various amounts of
startlift, port infrastructure (#berths, #AC handlers, etc...) and so
on;
b) The optimum number of the above to produce the quickest time; etc...
I would be very grateful if you could point me in a direction to find
if such a thing is possible and if so, whether the complexity of such a
solution would make it impractical.
Many many thanks. Sorry the question is so long (and most probably
confusing!)
Chris Riddle

with all the side considerations you mention, this is a mixed problem with
integer (#...) variables nad continuous variables, nonlinear and hence
there is no hope for an analytical solution. the problem generally fits
into "optimal control". especially minimum time otpimal control,
and even a simple looking problem like
minimal time take up and capture in two aircrafts combat
results in a hard mathematical
problem.
transportation problems with no time constraints on the other side can be solved
routinely, but also not via closed formulae
hth
peter 

Back to top 


christriddle@googlemail.c science forum beginner
Joined: 10 Jul 2006
Posts: 12

Posted: Thu Jul 13, 2006 8:42 am Post subject:
Logistic timestep problem



Hi,
First of all I'm not sure if this belongs here, if not, could you
suggest a more appropriate group.
I'm having some problems researching the possibility of explicit
solutions to military logistics problems.
Although, I think the actual problem is more general. I have a
timestep simulation tool that simulates strategiclift (aircraft,
ships, etc...) moving "stuff" from a start port to an end port.
Obviously aircraft make many flights back and forth.
While a timestep simulation suits this problem, it is quite expensive
in time.
The question I need answering is whether there exists an explicit
solution to such a problem. I'm pretty sure it's not linear, and
perhaps chaotic behaviour prevents such a solution.
By the way, when I say solution I mean things like finding:
a) How long it takes to move everything with various amounts of
startlift, port infrastructure (#berths, #AC handlers, etc...) and so
on;
b) The optimum number of the above to produce the quickest time; etc...
I would be very grateful if you could point me in a direction to find
if such a thing is possible and if so, whether the complexity of such a
solution would make it impractical.
Many many thanks. Sorry the question is so long (and most probably
confusing!)
Chris Riddle 

Back to top 


Google


Back to top 



The time now is Tue Jun 19, 2018 3:59 pm  All times are GMT

