ok

diff --git a/article.tex b/article.tex
index 00a0b3581dba4f8dab07e06056ad813cbc4d8a89..6c85d0c5c1477b27efce79d93c6a130f289dcfc8 100644 (file)
--- a/article.tex
+++ b/article.tex
@@ -204,9 +204,10 @@ network. Note that  centralized algorithms have the advantage  of requiring very
 low  processing  power  from  the  sensor  nodes,  which  usually  have  limited
 processing  capabilities. The  main drawback  of this  kind of  approach  is its
 higher cost in communications, since the  node that will make the decision needs
 low  processing  power  from  the  sensor  nodes,  which  usually  have  limited
 processing  capabilities. The  main drawback  of this  kind of  approach  is its
 higher cost in communications, since the  node that will make the decision needs

-information from all the  sensor nodes. Moreover, centralized approaches usually
+information from all the  sensor nodes. \textcolor{red} {Exact or heuristics approaches are designed to provide cover sets. (Moreover, centralized approaches usually

 suffer from the scalability problem, making them less competitive as the network
 suffer from the scalability problem, making them less competitive as the network

-size increases.
+size increases.) Contrary to exact methods, heuristic methods can handle very large and centralized problems. They are proposed to reduce computational overhead such as energy consumption, delay and generally increase in
+the network lifetime. }

 
 The first algorithms proposed in the literature consider that the cover sets are
 disjoint:  a  sensor  node  appears  in  exactly  one  of  the  generated  cover
 
 The first algorithms proposed in the literature consider that the cover sets are
 disjoint:  a  sensor  node  appears  in  exactly  one  of  the  generated  cover


@@ -555,7 +556,7 @@ implemented in each subregion in a distributed way.
 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
 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
+\textcolor{green} {of equal duration} 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
 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.
 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.


@@ -578,7 +579,8 @@ running out of energy), because it works in periods.
 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
 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.
+period starts. \textcolor{green}{The duration of the period  and the duration of the rounds are predefined parameters. Round duration should be long enough to hide the system control overhead and short enough to minimize the negative effects in case of node failure.}
+

 %%RC so if there are at least one failure per period, the coverage is bad...
 %%MS if we want to be reliable against many node failures we need to have an
 %% overcoverage...  
 %%RC so if there are at least one failure per period, the coverage is bad...
 %%MS if we want to be reliable against many node failures we need to have an
 %% overcoverage...  

diff --git a/reponse.tex b/reponse.tex
index dda571fa05d9da5496d54b47e69da0f56e5b895d..4c48b6fa73ef42e82cb364ce58d6d55b7731565a 100644 (file)
--- a/reponse.tex
+++ b/reponse.tex
@@ -78,7 +78,12 @@ point, as clustering may have a significant impact on solution quality. Not only
 the size of the subregion should be discussed and analyzed, but also the
 clustering strategy.\\
 
 the size of the subregion should be discussed and analyzed, but also the
 clustering strategy.\\
 

-\textcolor{blue}{\textbf{\textsc{Answer:}      }}\\
+\textcolor{blue}{\textbf{\textsc{Answer:} In the study,  we assume that
+    the deployment  of sensors is  almost uniform over  the region.  So  we only
+    need to  fix a regular  division of the region  into subregions to  make the
+    problem tractable.   The subdivision is  made such  that the number  of hops
+    between  any pairs  of sensors  inside  a subregion  is less  than or  equal
+    to~3. In particular, we discuss the number of subregions in......}}\\

 
 
 \noindent {\bf  2.}     Page 8
 
 
 \noindent {\bf  2.}     Page 8


@@ -92,7 +97,7 @@ two-phase approach where breach is minimized first, and then overcoverage is
 minimized would probably make more sense.
     \\
 
 minimized would probably make more sense.
     \\
 

-\textcolor{blue}{\textbf{\textsc{Answer:}      }}\\
+\textcolor{blue}{\textbf{\textsc{Answer:} As mentioned in the paper the integer program is based on the model proposed by () with some modifications. Their initial approach consisted in first finding the maximum coverage obtainable from available sensors to then use this information as input to the problem of minimizing the overcoverage. But this two-steps approach is time consuming. The originality of the model is to solve both objectives in a parallel fashion. Nevertheless the weights      }}\\

 
 
 
 
 
 


@@ -158,7 +163,7 @@ probably be tempered: heuristics and metaheuristics can handle very large and
 centralized problems (even if exact approaches can't), and these approaches are
 very popular in WSN.     } \\
 
 centralized problems (even if exact approaches can't), and these approaches are
 very popular in WSN.     } \\
 

-\textcolor{blue}{\textbf{\textsc{Answer:}    }}\\
+\textcolor{blue}{\textbf{\textsc{Answer:} Right, fixed    }}\\

 
 \noindent  {\ding{90}    Page 5
 "The choice of number and locations of primary points is the subject of another
 
 \noindent  {\ding{90}    Page 5
 "The choice of number and locations of primary points is the subject of another


@@ -172,7 +177,17 @@ All rounds seem to have the same duration. This should be stated explicitly, and
 justified (in column generation based approaches, "rounds" to not have the same
 duration).           }  \\
 
 justified (in column generation based approaches, "rounds" to not have the same
 duration).           }  \\
 

-\textcolor{blue}{\textbf{\textsc{Answer:}                }}\\
+\textcolor{blue}{\textbf{\textsc{Answer:} All rounds have the same duration. It is explicitly explained
+ in paragraph ... in section ....  This assumption leads to an integer formulation of the optimization problem. The decision variables are binary variables, $X_{t,j}$  for the activation ($X_{t,j}=1$)  or not ($X_{t,j}=0$) of the sensor $j$ during the round $t$. Column generation based approaches can be applied when the decision variables of the optimization problem are continuous. In this case the variables are the time intervals during which the sensors of a cover set (not necessarily disjoint) are active. The time intervals are not equal. Concerning the choice of round duration of equal length, it is correlated
+    with the types of applications, with the amount of initial energy in sensors
+    batteries,  and  also   with  the  duration  of  the   exchange  phase.  All
+    applications do not  have the same Quality of Service  requirements.  In our
+    case, information  exchange is executed  every hour,  but the length  of the
+    sensing period could be reduced and  adapted dynamically. On the one hand, a
+    small sensing period  would allow the network to be  more reliable but would
+    have higher  communication costs.  On the  other hand, the choice  of a long
+    duration may  cause problems  in case  of nodes  failure during  the sensing
+    period.   }}\\

 
 \noindent  {\ding{90}  Page 11 in Table 1
 $W_\Theta$ should be replaced with $W_\theta$
 
 \noindent  {\ding{90}  Page 11 in Table 1
 $W_\Theta$ should be replaced with $W_\theta$