\item larger remaining energy;
\item and then in case of equality, larger index.
\end{enumerate}
-Once chosen, the leader collects information to formulate and solve the integer program which allows to construct the set of active sensors in the sensing stage.
+Once chosen, the leader collects information to formulate and solve the integer program which allows to construct the set of active sensors in the sensing stage. \textcolor{blue}{The flow chart of PeCO protocol that executed in each sensor node is presented in \ref{flow6}.}
+
+\begin{figure}[ht!]
+\centering
+\includegraphics[scale=0.45]{Figures/ch6/Algo3.pdf} % 70mm
+\caption{The flow chart of PeCO protocol.}
+\label{flow6}
+\end{figure}
\section{Perimeter-based Coverage Problem Formulation}