the scheduling strategy for energy-efficient coverage.
Section~\ref{cp} gives the coverage model formulation which is used to
schedule the activation of sensors. Section~\ref{exp} shows the
the scheduling strategy for energy-efficient coverage.
Section~\ref{cp} gives the coverage model formulation which is used to
schedule the activation of sensors. Section~\ref{exp} shows the
proposed approach. Finally, we give concluding remarks and some
suggestions for future works in Section~\ref{sec:conclusion}.
proposed approach. Finally, we give concluding remarks and some
suggestions for future works in Section~\ref{sec:conclusion}.
work~\cite{Cardei:2005:IWS:1160086.1160098}. In~\cite{berman04}, the
authors have formulated the lifetime problem and suggested another
(LP) technique to solve this problem. A centralized solution based on the Garg-K\"{o}nemann
work~\cite{Cardei:2005:IWS:1160086.1160098}. In~\cite{berman04}, the
authors have formulated the lifetime problem and suggested another
(LP) technique to solve this problem. A centralized solution based on the Garg-K\"{o}nemann
\subsection{Information exchange phase}
Each sensor node $j$ sends its position, remaining energy $RE_j$, and
\subsection{Information exchange phase}
Each sensor node $j$ sends its position, remaining energy $RE_j$, and
its subregion by using an INFO packet and then listens to the packets
sent from other nodes. After that, each node will have information
about all the sensor nodes in the subregion. In our model, the
its subregion by using an INFO packet and then listens to the packets
sent from other nodes. After that, each node will have information
about all the sensor nodes in the subregion. In our model, the
select WSNL. The nodes in the same subregion will select the leader
based on the received information from all other nodes in the same
subregion. The selection criteria in order of priority are: larger
select WSNL. The nodes in the same subregion will select the leader
based on the received information from all other nodes in the same
subregion. The selection criteria in order of priority are: larger
sensing in the round (1 if yes and 0 if not);
\item $\Theta_{p}$ : {\it overcoverage}, the number of sensors minus
one that are covering the primary point $p$;
sensing in the round (1 if yes and 0 if not);
\item $\Theta_{p}$ : {\it overcoverage}, the number of sensors minus
one that are covering the primary point $p$;
It is important to have as few active nodes as possible in each round,
in order to minimize the communication overhead and maximize the
network lifetime. This point is assessed through the Active Sensors
It is important to have as few active nodes as possible in each round,
in order to minimize the communication overhead and maximize the
network lifetime. This point is assessed through the Active Sensors
\subsection{The impact of the number of rounds on the energy saving ratio}
In this experiment, we consider a performance metric linked to energy.
\subsection{The impact of the number of rounds on the energy saving ratio}
In this experiment, we consider a performance metric linked to energy.
performing one, since it takes longer to have the two subregion networks
simultaneously disconnected.
performing one, since it takes longer to have the two subregion networks
simultaneously disconnected.
runs per round for 150 deployed nodes. It can be observed that the
simple heuristic is the approach which stops first because the nodes
are randomly chosen. Among the two proposed strategies, the
runs per round for 150 deployed nodes. It can be observed that the
simple heuristic is the approach which stops first because the nodes
are randomly chosen. Among the two proposed strategies, the
-\includegraphics[scale=0.55]{TheNumberofStoppedSimulationRuns150.eps}
-\caption{The number of stopped simulation runs compared to the number of rounds for 150 deployed nodes }
+\includegraphics[scale=0.5]{TheNumberofStoppedSimulationRuns150g.eps}
+\caption{The percentage of stopped simulation runs compared to the number of rounds for 150 deployed nodes }
problems, one per subregion, that can be solved more easily.
In future work, we plan to study and propose a coverage protocol which
problems, one per subregion, that can be solved more easily.
In future work, we plan to study and propose a coverage protocol which
decision phase will compute the schedules for several sensing phases
which, aggregated together, define a kind of meta-sensing phase.
decision phase will compute the schedules for several sensing phases
which, aggregated together, define a kind of meta-sensing phase.