Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Approximation of a Fractional Order System by an Integer Order Model
  Using Particle Swarm Optimization Technique
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
15
The categories of this paper are: nucl-ex
0
The categories of this paper are: hep-ph
14
The categories of this paper are: math-ph
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph