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13 %\title{Response to the reviewers of \bf "Perimeter-based Coverage Optimization to Improve Lifetime in Wireless Sensor Networks"}
14 %\author{Ali Kadhum Idrees, Karine Deschinkela, Michel Salomon and Raphael Couturier}
22 \vspace{-0.5cm}\hspace{-2cm}FEMTO-ST Institute, UMR 6174 CNRS
24 \hspace{-2cm}University Bourgogne Franche-Comt\'e
26 \hspace{-2cm}IUT Belfort-Montb\'eliard, BP 527, 90016 Belfort Cedex, France.
31 Detailed changes and addressed issues in the revision of the article
33 ``Perimeter-based Coverage Optimization \\
34 to Improve Lifetime in Wireless Sensor Networks''\\
36 by Ali Kadhum Idrees, Karine Deschinkel, Michel Salomon and Raph\"ael Couturier
41 Dear Editor and Reviewers,
43 First of all, we would like to thank you very much for your kind help to improve
44 our article named: ``Perimeter-based Coverage Optimization to Improve Lifetime
45 in Wireless Sensor Networks''. We highly appreciate the detailed valuable
46 comments of the reviewers on our article. The suggestions are quite helpful for
47 us and we incorporate them in the revised article. We are happy to submit to you
48 a revised version that considers most of your remarks and suggestions to improve
49 the quality of our article.
51 As below, we would like to clarify some of the points raised by the reviewers
52 and we hope the reviewers and the editors will be satisfied by our responses to
53 the comments and the revision for the original manuscript.
55 %Journal: Engineering Optimization
56 %Reviewer's Comment to the Author Manuscript id GENO-2015-0094
57 %Title: \bf "Perimeter-based Coverage Optimization to Improve Lifetime in Wireless Sensor Networks"
58 %Authors: Ali Kadhum Idrees, Karine Deschinkela, Michel Salomon and Raphael Couturier
60 \section*{Response to Reviewer No. 1 Comments}
62 This paper proposes a scheduling technique for WSN to maximize coverage and
63 network lifetime. The novelty of this paper is the integration of an existing
64 perimeter coverage measure with an existing integer linear programming
65 model. Here are few comments:\\
70 \noindent {\bf 3.} The communication and information sharing required to
71 cooperate and make these decisions was not discussed.\\
73 \textcolor{blue}{\textbf{\textsc{Answer:} The communication and information
74 sharing required to cooperate and make these decisions is discussed at the
75 end of page 8. Position coordinates, remaining energy, sensor node ID, and
76 number of one-hop neighbors are exchanged.}}\\
78 \textcolor{red}{\textbf{\textsc{Reviewer's response:} I see at the end of page 8 the description of the INFO packet. However, you are not including any description of the position coordinates, remaining energy, sensor node ID, etc. in the write up. I suggest adding this into the write up to make the communication clear.}}\\
81 \noindent {\bf 6.} The authors have performed a thorough review of existing
82 coverage methodologies. However, the clarity in the literature review is a
83 little off. Some of the descriptions of the method s used are very vague and do
84 not bring out their key contributions. Some references are not consistent and I
85 suggest using the journals template to adjust them for overall consistency.\\
87 \textcolor{red}{\textbf{\textsc{Reviewer's response:} I do like the way you have presented the different literature related to each aspect of
88 the problem. I think I was just concerned that the sentences presenting each work are not very
89 clear. After reading through them however, everything is clear. I like the addition of the last
90 paragraph and believe it is definitely needed since you are directly comparing these
94 \textcolor{blue}{\textbf{\textsc{Answer:} References have been carefully checked
95 and seem to be consistent with the journal template. In Section~2, ``Related
96 literature'', we refer to papers dealing with coverage and lifetime in
97 WSN. Each paragraph of this section discusses the literature related to a
98 particular aspect of the problem : 1. types of coverage, 2. types of scheme,
99 3. centralized versus distributed protocols, 4. optimization method. At the
100 end of each paragraph we position our approach. We have also added a last
101 paragraph about our previous work on DiLCO protocol to explain the
102 difference with PeCO. }}\\
104 \noindent {\bf 7.} The methodology is implemented in OMNeT++ (network simulator)
105 and tested against 2 existing algorithms and a previously developed method by
106 the authors. The simulation results are thorough and show that the proposed
107 method improves the coverage and network lifetime compared with the 3 existing
108 methods. The results are similar to previous work done by their team.\\
110 \textcolor{red}{\textbf{\textsc{Reviewer's response:}
111 I agree that you should show the same performance indicators and that this paper is
112 about the way you formulated the problem. The mathematical optimization model is the main
113 contribution but it’s less convincing since the results are slightly better if not the same for the two
114 methodologies you have developed. Could you include some other measure that shows that the
115 PeCO is better? Maybe include computation time or something that is as convincing as the energy
116 consumed per sensor.}}
118 \textcolor{blue}{\textbf{\textsc{Answer:} Although the study conducted in this
119 paper reuses the same protocol presented in our previous work, we focus in
120 this paper on the mathematical optimization model developed to schedule
121 nodes activities. We deliberately chose to keep the same performance
122 indicators to compare the results obtained with this new formulation with
123 other existing algorithms.}}\\
125 \noindent {\bf 8.} Since this paper is attacking the coverage problem, I would
126 like to see more information on the amount of coverage the algorithm is
127 achieving. It seems that there is a tradeoff in this algorithm that allows the
128 network to increase its lifetime but does not improve the coverage ratio. This
129 may be an issue if this approach is used in an application that requires high
132 \textcolor{blue}{\textbf{\textsc{Answer:} Your remark is very interesting. Indeed,
133 Figures 8(a) and (b) highlight this result. The PeCO protocol allows to achieve
134 a coverage ratio greater than $50\%$ for far more periods than the others
135 three methods, but for applications requiring a high level of coverage
136 (greater than $95\%$), the DiLCO method is more efficient. It is explained at
137 the end of Section 5.2.4.}}\\
139 \textcolor{red}{\textbf{\textsc{Reviewer's response:}
140 I’m glad you added the explanation. I am confused with your conclusion in the last
141 sentence though, “DiLCO is better for coverage ratios near 100%, but in that case PeCO is not
142 ineffective for the smallest network sizes”. I suggest adjusting it to something like this. “DiLCO
143 outperforms PeCO when the coverage ratio is required to be >90%, but PeCo extends the network
144 lifetime significantly when coverage ratio can be relaxed. “ Also, can you add applications where
145 you would want to have a coverage ratio of 50%? This seems like a very small ratio and as you
146 increase it, DiLCO becomes the methodology that has the maximum network lifetime. If you don’t
147 include application examples, your statement “Indeed there are applications that do not require a
148 100$\%$ coverage of the area to be monitored.” stronger. }}
154 We are very grateful to the reviewers who, by their recommendations, allowed us
155 to improve the quality of our article.