\quad%
\subfloat[Comparison the selected frequency scaling factors for 8 nodes]{%
\includegraphics[width=.24\textwidth]{fig/three_scenarios}\label{fig:scales_comp}}
\quad%
\subfloat[Comparison the selected frequency scaling factors for 8 nodes]{%
\includegraphics[width=.24\textwidth]{fig/three_scenarios}\label{fig:scales_comp}}