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-%% CHAPITRE 04 %%
+%% CHAPTER 04 %%
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smaller areas, called subregions, and then our MuDiLCO protocol will be
implemented in each subregion in a distributed way.
-As can be seen in Figure~\ref{fig2}, our protocol works in periods fashion,
+As can be seen in Figure~\ref{fig2}, our protocol works in periods fashion,
where each is divided into 4 phases: Information~Exchange, Leader~Election,
Decision, and Sensing. Each sensing phase may be itself divided into $T$ rounds
and for each round a set of sensors (a cover set) is responsible for the sensing
-task. In this way a multiround optimization process is performed during each
+task. In this way a multiround optimization process is performed during each
period after Information~Exchange and Leader~Election phases, in order to
produce $T$ cover sets that will take the mission of sensing for $T$ rounds.
\begin{figure}[ht!]
This protocol minimizes the impact of unexpected node failure (not due to batteries
running out of energy), because it works in periods.
- On the one hand, if a node failure is detected before making the
-decision, the node will not participate to this phase, and, on the other hand,
-if the node failure occurs after the decision, the sensing task of the network
-will be temporarily affected: only during the period of sensing until a new
-period starts.
+ On the one hand, if a node failure is detected before making the decision, the node will not participate to this phase, and, on the other hand, if the node failure occurs after the decision, the sensing task of the network will be temporarily affected: only during the period of sensing until a new period starts.
-The energy consumption and some other constraints can easily be taken into
-account, since the sensors can update and then exchange their information
-(including their residual energy) at the beginning of each period. However, the
-pre-sensing phases (Information Exchange, Leader Election, and Decision) are
-energy consuming for some nodes, even when they do not join the network to
-monitor the area.
+The energy consumption and some other constraints can easily be taken into account, since the sensors can update and then exchange their information (including their residual energy) at the beginning of each period. However, the pre-sensing phases (Information Exchange, Leader Election, and Decision) are energy consuming for some nodes, even when they do not join the network to monitor the area.
These phases can be described in more details as follow:
\subsection{Decision phase}
\label{ch4:sec:02:02:03}
-Each WSNL will solve an integer program to select which cover sets will be
+Each WSNL will solve an integer program to select which cover sets will be
activated in the following sensing phase to cover the subregion to which it
belongs. The integer program will produce $T$ cover sets, one for each round.
The WSNL will send an Active-Sleep packet to each sensor in the subregion based
the benefit from the optimization and the execution time needed to solve
it. Therefore, we have set the number of subregions to 16 rather than 32.
-We have used an energy consumption model, which is presented in chapter 1, section \ref{ch1:sec9:subsec2}. The initial energy of each node is randomly set in the interval $[500;700]$. A sensor node will not participate in the next round if its remaining energy is less than $E_{R}=36~\mbox{Joules}$, the minimum energy needed for the node to stay alive during one round. This value has been computed by multiplying the energy consumed in active state (9.72 mW) by the time in second for one round (3600 seconds). According to the interval of initial energy, a sensor may be alive during at most 20 rounds.
+We used the modeling language and the optimization solver which are mentioned in chapter 3, section \ref{ch3:sec:04:02}. In addition, we employed an energy consumption model, which is presented in chapter 3, section \ref{ch3:sec:04:03}.
+
+%The initial energy of each node is randomly set in the interval $[500;700]$. A sensor node will not participate in the next round if its remaining energy is less than $E_{R}=36~\mbox{Joules}$, the minimum energy needed for the node to stay alive during one round. This value has been computed by multiplying the energy consumed in active state (9.72 mW) by the time in second for one round (3600 seconds). According to the interval of initial energy, a sensor may be alive during at most 20 rounds.
\subsection{Metrics}
\label{ch4:sec:03:02}
$t$ in the current sensing phase, $|J|$ is the total number of sensors in the
network, and $R$ is the total number of subregions in the network.
-\item {{\bf Network Lifetime}:} is described in chapter 3, section \ref{ch3:sec:04:02}.
+\item {{\bf Network Lifetime}:} is described in chapter 3, section \ref{ch3:sec:04:04}.
\item {{\bf Energy Consumption (EC)}:} the average energy consumption can be
seen as the total energy consumed by the sensors during the $Lifetime_{95}$ or
before receiving the decision to go active or sleep in period $m$.
$E^{\scriptsize \mbox{comp}}_m$ refers to the energy needed by all the leader
nodes to solve the integer program during a period. Finally, $E^a_t$ and $E^s_t$
-indicate the energy consummed by the whole network in round $t$.
+indicate the energy consumed by the whole network in round $t$.
-\item {{\bf Execution Time}:} is described in chapter 3, section \ref{ch3:sec:04:02}.
+\item {{\bf Execution Time}:} is described in chapter 3, section \ref{ch3:sec:04:04}.
-\item {{\bf Stopped simulation runs}:} is described in chapter 3, section \ref{ch3:sec:04:02}.
+\item {{\bf Stopped simulation runs}:} is described in chapter 3, section \ref{ch3:sec:04:04}.
\end{enumerate}
