From bf13dc4be2df34e44e4cf16752f8804d3e160caa Mon Sep 17 00:00:00 2001 From: couturie Date: Tue, 13 Aug 2013 20:57:23 +0200 Subject: [PATCH] ok pour les modifs de michel --- bare_conf.tex | 32 ++++++++++---------------------- 1 file changed, 10 insertions(+), 22 deletions(-) diff --git a/bare_conf.tex b/bare_conf.tex index b9ed86e..90482fc 100755 --- a/bare_conf.tex +++ b/bare_conf.tex @@ -110,12 +110,10 @@ coverage problem, with the objective of maximizing the network lifetime by using an adaptive scheduling. The area of interest is divided into subregions and an activity scheduling for sensor nodes is planned for each subregion. -% DEBUT AJOUT -{\bf In fact, the nodes in a subregion can be seen as a cluster where + In fact, the nodes in a subregion can be seen as a cluster where each node sends sensing data to the cluster head or the sink node. Furthermore, the activities in a subregion/cluster can continue even - if another cluster stops due to too much node failures.} -% FIN AJOUT + if another cluster stops due to too much node failures. Our scheduling scheme considers rounds, where a round starts with a discovery phase to exchange information between sensors of the subregion, in order to choose in suitable manner a sensor node to @@ -672,11 +670,9 @@ simulator OMNeT++ \cite{varga}. We performed simulations for five different densities varying from 50 to 250~nodes. Experimental results were obtained from randomly generated networks in which nodes are deployed over a $(50 \times 25)~m^2 $ sensing field. -% DEBUT MODIFICATION -{\bf More precisely, the deployment is controlled at a coarse scale in +More precisely, the deployment is controlled at a coarse scale in order to ensure that the deployed nodes can fully cover the sensing - field with the given sensing range.} -% FIN MODIFICATION + field with the given sensing range. 10~simulation runs are performed with different network topologies for each node density. The results presented hereafter are the average of these 10 runs. A simulation @@ -863,11 +859,8 @@ A sensor node has limited energy resources and computing power, therefore it is important that the proposed algorithm has the shortest possible execution time. The energy of a sensor node must be mainly used for the sensing phase, not for the pre-sensing ones. -Table~\ref{table1} gives the average execution times {\bf in seconds} -on a laptop of the decision phase -% DEBUT AJOUT -{\bf (resolution of the optimization problem)} -% FIN AJOUT +Table~\ref{table1} gives the average execution times in seconds +on a laptop of the decision phase (solving of the optimization problem) during one round. They are given for the different approaches and various numbers of sensors. The lack of any optimization explains why the heuristic has very low execution times. Conversely, the Strategy @@ -922,11 +915,9 @@ nodes have been drained of their energy or each sensor network monitoring an area becomes disconnected. In figure~\ref{fig8}, the network lifetime for different network sizes and for both Strategy with Two Leaders and the Simple Heuristic is illustrated. -% DEBUT MODIFICATION -{\bf We do not consider anymore the centralized Strategy with One + We do not consider anymore the centralized Strategy with One Leader, because, as shown above, this strategy results in execution - times that quickly become unsuitable for a sensor network.} -% FIN MODIFICATION + times that quickly become unsuitable for a sensor network. \begin{figure}[h!] %\centering @@ -982,12 +973,9 @@ problems, one per subregion, that can be solved more easily. In future, we plan to study and propose a coverage protocol which computes all active sensor schedules in a single round, using optimization methods such as swarms optimization or evolutionary -algorithms. -% DEBUT AJOUT -{\bf This single round will still consists of 4 phases, but the +algorithms. This single round will still consists of 4 phases, but the decision phase will compute the schedules for several sensing phases - which aggregated together define a kind of meta-sensing phase.} -% FIN AJOUT + which aggregated together define a kind of meta-sensing phase. The computation of all cover sets in one round is far more difficult, but will reduce the communication overhead. -- 2.39.5