Model copes with chaos to deliver relief

Computer program helps responders transport supplies in tough conditions

By Rachel Ehrenberg

Science News, Web edition: Monday, February 21^st, 2011

WASHINGTON — Getting blood or other

perishable supplies to an area that’s been struck by

an earthquake or hurricane isn’t as simple as asking

what brown can do for you. But a new model quickly

5 determines the best routes and means for delivering

humanitarian aid, even in situations where bridges

are out or airport tarmacs are clogged with planes.

The research, presented February 18 at the

annual meeting of the American Association for the

10 Advancement of Science, could help get supplies to

areas which have experienced natural disasters or

help prepare for efficient distribution of vaccines when

the flu hits.

Efficient supply chains have long been a goal

15 of manufacturers, but transport in fragile networks

— where supply, demand and delivery routes may

be in extremely rapid flux — requires a different

approach, said Anna Nagurney of the University of

Massachusetts Amherst, who presented the new work.

20 Rather than considering the shortest path from one

place to another to maximize profit, her system aims

for the cleanest path at minimum cost, while capturing

factors such as the perishability of the product and

the uncertainty of supply routes. ‘You don’t know

25 where demand is, so it’s tricky,’ said Nagurney. ‘It’s a

multicriteria decision-making problem.’

By calculating the total cost associated with

each link in a network, accounting for congestion and

incorporating penalties for time and products that are

30 lost, the computer model calculates the best supply

chain in situations where standard routes may be

disrupted.

‘Mathematical tools are essential to develop

formal means to predict, and to respond to, such

35 critical perturbations,’ said Iain Couzin of Princeton

University, who uses similar computational tools to

study collective animal behavior. ‘This is particularly

important where response must be rapid and

effective, such as during disaster scenarios … or

40 during epidemics or breaches of national security.’

The work can be applied to immediate, pressing

situations, such as getting blood, food or medication

to a disaster site, or to longer-term problems such as

determining the best locations for manufacturing flu

45 vaccines.

<http://www.sciencenews.org/view/generic/id/70083/title/Model_copes_with_chaos_to_deliver_relief>. Retrieved April 7^th, 2011.

“such critical perturbations,” (lines 34-35) refers to all the items below, EXCEPT