Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Computer Simulations of Pedestrian Dynamics and Trail Formation   A simulation model for the dynamic behaviour of pedestrian crowds is
mathematically formulated in terms of a social force model, that means,
pedestrians behave in a way as if they would be subject to an acceleration
force and to repulsive forces describing the reaction to borders and other
pedestrians. The computational simulations presented yield many realistic
results that can be compared with video films of pedestrian crowds. Especially,
they show the self-organization of collective behavioural patterns.
  By assuming that pedestrians tend to choose routes that are frequently taken
the above model can be extended to an active walker model of trail formation.
The topological structure of the evolving trail network will depend on the
disadvantage of building new trails and the durability of existing trails.
Computer simulations of trail formation indicate to be a valuable tool for
designing systems of ways which satisfy the needs of pedestrians best. An
example is given for a non-directed trail network.

1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
36
The categories of this paper are: cmp-lg
37
The categories of this paper are: supr-con
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
3
The categories of this paper are: physics
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph