Solving the Container Relocation Problem by Using a Metaheuristic Genetic Algorithm

Round 1

Reviewer 1 Report

The study is interesting, but some comments should be addressed:

1.       The title should be revised. Particularly this section, “A Novel Model Based on Genetic Algorithm” , is very confusing. Also, authors in many sections indicate “novel model-based” while in metaheuristic studies, it is not an acceptable term.

2.       All pseudo-codes should be improved and polished. Their qualities are very low. In addition, some parts of the proposed pseudo-code for GA are not aligned with explanations in the body of the paper.

3.       Please explain the capability of the employed mutation and crossover in maintaining the feasibility of the generated solutions. Are ALL generated solutions still feasible?

4.       Statistical tests should be conducted to support the superiority of the proposed method against other methods.

5.       The Logic of the introduction is acceptable and readable. Good!

6.       Limitations of the study should be highlighted in conclusion.

7.       The possibility of using other novel metaheuristic algorithms such as Lion Optimization algorithm and Red deer algorithm in future studies should be suggested.

8.       The used parameters should be summarised in a table.

9.       Some recent studies have been missed in the literature review. Please update the literature review.

Author Response

Dear Reviewer 1,

Thank you for giving us the opportunity to submit a revised version of the manuscript ‘A Novel Model Based on Genetic Algorithm for Solving the Container Relocation Problem’. We appreciate the time and effort that you dedicated to providing us great feedback, and insightful comments on which basis we can do valuable improvements to our manuscript. We have incorporated most of your suggestions. Those changes are highlighted in the manuscript (yellow highlighted). Please see below, in a table format (for better checkup view), point-by-point responses to your comments. All page numbers and lines refer to the revised manuscript file.

Sincerely,

Authors

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper describes interesting modeling and solving methods applied to the Container Relocation Problem for container ports. Although, it needs a major review to be tackled and enable to know what it is the paper's contribution to the literature:

(1) At the end of the introduction, it is not clear what is the main paper's contributions to the literature. Maybe a list of paper contributions would be helpful for the readers.

(2) Since on page 3:

"The results of our new model, compared with the results of different best models obtained on the most complex test instances of restricted CRPs [24], have shown that our proposed model achieves optimal or near-optimal solutions for most test instances."

Comment: This affirmation is strong since it compares with optimal solutions. Although, the paper [24] does not have an integer mathematical model which solution could bring the certainty of optimal solutions. Therefore, the phrase should be rewritten to make clear how this optimal solution could be achieved and compared with the ones from the current model.

(2) Concerns about the mathematical model:

(2.1) It is a paper's original contribution? If it is, how does it differ from other mathematical models, and why use it?

(2.2) The paper did not show a very complete integer mathematical model and it was not possible to see: 

(i) computational results showing what are the model limitations in terms

of solving instances according to their size;

(ii) what kind of optimal behavior could be expected in the solutions of small instances;

(iii) The relaxed linear programming model version of the integer model could not serve as an estimation of the gap in the solutions from GA?

(3) On page 7, section "4.2. A new model for CRP resolving":

Comment: This section should be the most important of the paper, describing in detail what is the paper's contribution. Although, there is no information about this and the reason why the paper is different from previous approaches.

(3) About the Genetic Algorithm:

(3.1) On page 7, section "4.2. A new model for CRP resolving":

Comment: This section should be the most important of the paper, describing in detail what is the paper's contribution. Although, there is no information about this and the reason why the paper is different from previous approaches.

On pages 7, and 10:

Algorithms 1 and 2 employed several symbols, but without a previous section with a description of what they mean. For example, in Algorithm 2, what is the meaning of indT, CC, IGC, and other symbols? Maybe a flowchart would be more interesting to describe in general terms the necessary steps to be carried out.

(4) About the experimental results:

(4.1) It seems the paper contributes to the literature is the proposition of a new algorithm and maybe a comparison with previously implemented methods. Although, no statistical test proves that the solutions from the method performance are better than the previous paper's method. The evidence is contrary on page 17, according to the row 'Total sum of average relocations',  the best result is achieved using GA with rules [17]. This is validated with the following phrase: "Compared to the results obtained in [24], the proposed model is worse by 0.3%." So, the conclusion is that the [24] method is preferable to the proposed one.

(4.2) It would be interesting to perform some kind of statistical test to compare the method's performance like a hypothesis test.

(4.3) For didactic purposes, one instance could be selected and maybe the detailed Gantt graphic of solutions from different methods should be shown and commented on.

Author Response

Dear Reviewer 2,

Thank you for giving us the opportunity to submit a revised version of the manuscript ‘A Novel Model Based on Genetic Algorithm for Solving the Container Relocation Problem’. We appreciate the time and effort that you dedicated to providing us great feedback, and insightful comments on which basis we can do valuable improvements to our manuscript. We have incorporated most of your suggestions. Those changes are highlighted in the manuscript (yellow highlighted). Please see below, in a table format (for better checkup view), point-by-point responses to your comments. All page numbers and lines refer to the revised manuscript file.

Sincerely,

Authors

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

in line 643 please use appropriate reference for the algorithms which are

Fathollahi-Fard, Amir Mohammad, Mostafa Hajiaghaei-Keshteli, and Reza Tavakkoli-Moghaddam. "Red deer algorithm (RDA): a new nature-inspired meta-heuristic." Soft Computing 24.19 (2020): 14637-14665.

Yazdani, Maziar, and Fariborz Jolai. "Lion optimization algorithm (LOA): a nature-inspired metaheuristic algorithm." Journal of computational design and engineering 3.1 (2016): 24-36.

Author Response

Dear Reviewer 1,

Thank you for giving us the opportunity to submit a revised version of the manuscript ‘A Novel Model Based on Genetic Algorithm for Solving the Container Relocation Problem’. We appreciate the time and effort that you dedicated to providing us great feedback, and insightful comments on which basis we can do valuable improvements to our manuscript. We have incorporated most of your suggestions. Those changes are highlighted in the manuscript (yellow highlighted). Please see below, in a table format, the response to your comment. All page numbers and lines refer to the revised manuscript file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The authors made a significant review addressing all points from this reviewer. The paper contributions are now clear.

Author Response

Dear Reviewer 2,

Thank you for your time and effort in providing us with great feedback and insightful comments during the review process, based on which we have made valuable improvements to our manuscript.

Sincerely,

Authors