Docent vertelt: Taalonderzoek binnen en buiten de gebaande paden

Have you ever stood to wait for
a bus or a train? Or have you been
caught in a traffic jam waiting patiently
for the other cars to move?
If you are like me, you will have
looked at your watch, you will have
walked up and down the track and
you will have called the transport
system very inappropriate things.
Here let us try another approach:
Why do we have to wait?
What is the reason? Technical
difficulties, human errors and bad
weather conditions pop up in our
mind like mystical grand answers.
But as we are scientists we have
to look beyond this convincing appearance
and understand the real
cause of the phenomena. If we do
this we will find, that most of the
time there is just a single defect
occurring. This defect propagates
through the whole network as increasing
delays. The result ranges
from an uncomfortable waiting period
to a complete break-down of
the system (catastrophe).
Now if we would be anything but
engineers, apart from being scientists,
we might be tempted to say
that this is just how the world is. But
we are engineers and so we have
to ask: Is this necessary? Or more
concrete: Is there a transport system
possible without this problems?
We do not have to look far. In fact
we don’t even need to stand up. Just
take a look at your arm. How many
blood cells do you think are moving
5
Transport & Turing
Niklas Semmler
through your veins every minute?
Yet have you ever heard about a
traffic jam of blood cells? (And if
you have how many people do you
think would be alive if it happened
a lot?)
Many living organisms use
transport networks in one way or
another. So it must be possible,
to make a system that is at least
partially more stable. To understand
their principles scientists have
observed the most simple of organisms.
One of those, which has
made quite a name for itself, is the
Physarum Polycephalum, the multiheaded
slime mold (also see figure
1).
Given that we have a friendly environment
this cute little thing will
create a network between all of its
sources of food (or nutrients). This
behavior is part of the life-cycle
that biologists have investigated for
years. Okay, that is not very impressive.
There is probably a crazy
scientist for every topic. Still the
findings of these few might actually
interest us a lot. For example,
if you use the food sources as a
substitute for existing cities you can
simulate the creation of a railway
network. The Japaneseresearchers
around Nakagaki, Ueda, Yamada
and Tero have shown that the structure
of the plasmodium network is
between 10% to 16% more fault tolerant
than its real counterpart (14%
or 20% against 4%). (And don’t for-