\begin{table}%t2
\caption{\label{perres}Performance test results.} 
%\centerline
{\small
\begin{tabular}{c c c c c c c c c} 
\hline\hline 
\# & pop & gen & $T_{\rm dust}$ &  $f_2$ & $f_3$ & $\tau_{10~\mu{}\rm m}$ & Free paras& Fitness\\ 
\hline 
0 & artificial& spectrum& 750 & 65 & 35 & 0.009 & -- & -- \\ 
\hline 
1 & 10 & 5 & 754 & -- & -- & -- & 1 & 0.019\\
2 & 10 & 5 & -- & 65 & 35 & -- & 1 & 1.000\\
3 & 10 & 5 & -- & -- & -- & 0.00898 & 1 & 0.023\\
4 & 10 & 5 & -- & 66.5 & 33.5 & 0.00878 & 2 & 0.552\\
5 & 10 & 5 & 752 & 50.3 & 49.7 & 0.00827 & 3 & 0.664\\
6 & 30 & 20 & -- & 66.6 & 33.4 & 0.00783 & 2 & 0.777\\
7 & 30 & 20 & 730 & 65.6 & 34.4 & 0.008837 & 3 & 0.969\\
\hline
\end{tabular}}
\tablefoot{The fitness has been normalised to the fittest model (No.~2) in this test.}\vspace*{2mm}
\end{table}