Integrated Production and Transportation Scheduling in E-Commerce Supply Chain with Carbon Emission Constraints

Round 1

Reviewer 1 Report

The paper investigates optimization of supply chain operation from a
low-carbon perspective. 
The paper considers an important practical problem. Multi-level genetic algorithm is used to solved proposed optimization problem.
Simple genetic operators are implemented. More genetic operators could be tested and comparison with other algorithms, metaheuristics should be performed.
The experimental section is not sufficient: only simple experiments were conducted, it is not described how the parameters for the genetic algorithm were selected, it is not shown how the quality of solutions is improved with increasing numbers of Popsize or Maxgen, etc.

Additional remarks:

• some symbols and formulas are invisible in pdf, e.g. in lines 196-198, 213,
• word 'optimal' in line 296 is not correct (genetic algorithm is heuristic),
• denerations => generations in figure 3.

Author Response

Point 1: The paper investigates optimization of supply chain operation from a low-carbon perspective.

The paper considers an important practical problem. Multi-level genetic algorithm is used to solved proposed optimization problem.

Simple genetic operators are implemented. More genetic operators could be tested and comparison with other algorithms, metaheuristics should be performed.

The experimental section is not sufficient: only simple experiments were conducted, it is not described how the parameters for the genetic algorithm were selected, it is not shown how the quality of solutions is improved with increasing numbers of Popsize or Maxgen, etc.

Response 1: The comment is very important. We added section 6.2 Comparative Analysis of Algorithms. In this part, we added more data to prove my research results.

Point 2: Additional remarks:

some symbols and formulas are invisible in pdf, e.g. in lines 196-198, 213,

word 'optimal' in line 296 is not correct (genetic algorithm is heuristic),

denerations => generations in figure 3.

Response 2: Your suggestions are so kind to point out the mistakes of this work. We are really sorry for the careless mistakes. According to your valuable suggestions, we have carefully revised your mentioned mistakes, and figure 3 is modified. we have also carefully recheck the whole paper to revise other mistakes.

Reviewer 2 Report

Dear Authors,

Please find below some suggestions to improve your paper:

• In the TITLE: The problem you are addressing, as deduced from section 6-experimental analysis, is more related with the optimization of routes in both scenarios, centralized and decentralized supply chain, considering costs and GHG emissions as optimization functions than with the E-commerce. The involvement of the E-commerce in the problem, the method and the solution is very poor and it can create false expectations to the readers. My suggestion is to remove the E-commerce concept from the title and the manuscript as it is not really addressed.
• In the ABSTRACT:
  • • The next statement should be revised "...The results show that the centralized decision-making mode plays the role of the carbon emission constraints to the greatest extent, although the carbon  emissions are large, the cost is the smallest...". From the Table 4.-Test results, it is deduced that both costs and carbon emissions are smallest in a centralized scenario.
• • • It is recommended to explicitly mention in the abstract who is interesting this study for (transport planners, environmental experts, ...) and further developments. 
• About CITATIONS: Please review the citation system. References (at the end of the manuscript) should be ordered in alphabetic order and citations should be done appropriately (for instance, "Shen (2021)" in line 80 should be replaced by "Shen et al. (2021)"
• In the TEXT of the paper: 
  • • Remove the word "function" in line 111. "The objective is to minimize the sum of production cosrs and distribution costs,..."
    • Remake the sentence 167 to 170, as it is not clear to the reader and some words are repeated too much.
    • Some figures or letters are missing in lines 196 and 197, the same than in the line 213.
    • Replace the words "Assumption" per "Hypotesis" in lines 219 and 221, and it should be added an "s" in the word "order" in the line 221.  
    • The meaning of the variables should be placed just after each equation where variables are mentioned, and not all listed in one sheet. This will clarify the understanding of the reader.
    • The meaning of some variables as X_0jm, Xijm and y_im is not mentioned in the text.
    • Define what is "h" in the equation 5.
    • "i" is the origin of the road segment but also the number of customers. Please review.
    • In the equation 3, the limits of index "i" and "k" are the same ("N"). Please review.
    • In the equation 3, magnituds are not coherent beacuse E_S^tr is representing the carbon emissions "per unit of time" and the other adding terms are not "per unit of time". Please review.
    • Please correct the word "re-detects" in the line 305. 
    • Add a reference linked to the "Topcuoglu's theory".
    • Please explain what "Popsize" (line 379) and "Maxgen" (line 381) is conceptually representing. Consider that readers of the paper must not be experts in MATLAB.
    • Please review the sentence from line 381 to 386 for the justification of W_E and W_C selection.
    • It seems that Table 2 is Table 1 and Table 2 (mentioned in line 385) is in fact missing.
    • In the presentation of the experimental case is said that "there are 10 homogeneous vehicles" (line 372), however in the results showed in "Table 3" only 4 vehicles are mentioned. Please review.
    • In the "Table 4", units for "costs" and "carbon emissions" are missing. 
    • Please review the lines 422 and 423 where is said that "Although the carbon emissions are large, the cost is the smallest.", because according to the "Table 4", both carbon emissions and costs are smaller in the centralized decition-making mode.
• CONCEPTUAL improvements:
  • • In the Section 5.- "Multilevel genetic algorithm design" and Section 6.- "Experimental analysis", It should be clearer to the reader the process of chromosomes and genes assignment and how the crossover, mutation and repairing is made on them. This is very slightly mentioned in the text and in a very general way. It is required to be more specific there and how this is applied to the experimental case. This will help a lot to understand how figures 4 and 5 in the section 6 are achieved. In the current status they are quite confussing.  
    • In the Section 1-Introduction or in the Section 2- Literature review, a justification of the method selected to solve the problem should be introduced. The optimization of routes from a distance perspective (which is linked to carbon emissions) can be also addressed by other methods different to genetic algorithms. For instance, ant colony optimization algorithms for the Travelling Salesman Problem.
• About the CONCLUSION: This section should be extended addressing a deeper discussion about the problem, the selection of the method, its limitations, the achieved results and what further developments should be addressed in future studies to continue with this research line.

Thanks very much in advance for considering these suggestions of improvement. 

Author Response

Point 1: In the TITLE: The problem you are addressing, as deduced from section 6-experimental analysis, is more related with the optimization of routes in both scenarios, centralized and decentralized supply chain, considering costs and GHG emissions as optimization functions than with the E-commerce. The involvement of the E-commerce in the problem, the method and the solution is very poor and it can create false expectations to the readers. My suggestion is to remove the E-commerce concept from the title and the manuscript as it is not really addressed.

Response 1: Thanks for the valuable comment and suggestion. Chinese companies are gradually optimizing the structure of the supply chain，and transition to supply chain model under the e-commerce environment. The development of e-commerce has transformed the supply chain structure to an integrated operation of production and transportation, which has an impact on the cost and carbon emissions of the supply chain. Meanwhile, integrated production and transportation scheduling problem is proposed in the e-commerce environment. We updated the manuscript by modifying the introduction of the manuscript, and described integrated production and transportation scheduling problem in e-commerce supply Chain with Carbon emission Constraint in more detail.

Point 2: In the ABSTRACT: The next statement should be revised "...The results show that the centralized decision-making mode plays the role of the carbon emission constraints to the greatest extent, although the carbon emission are large, the cost is the smallest...". From the Table 4.-Test results, it is deduced that both costs and carbon emissions are smallest in a centralized scenario.

It is recommended to explicitly mention in the abstract who is interesting this study for (transport planners, environmental experts, ...) and further developments.

Response 2: Thanks for the valuable comment. Considering the suggestions from reviewer, we have carefully revised your mentioned mistakes and modified the abstract. In the abstract，we explicitly mention that transportation experts, business managers and government departments are interesting in this study and made clear the direction of further development.

Point 3: About CITATIONS: Please review the citation system. References (at the end of the manuscript) should be ordered in alphabetic order and citations should be done appropriately (for instance, "Shen (2021)" in line 80 should be replaced by "Shen et al. (2021)"

Response 3: This comment is very valuable. We have carefully checked all citations, and similar errors have been revised.

Point 4: In the TEXT of the paper: Remove the word "function" in line 111. "The objective is to minimize the sum of production cosrs and distribution costs, ..." Remake the sentence 167 to 170, as it is not clear to the reader and some words are repeated too much.

Response 4: Thanks for the valuable comment and suggestion. The word “function” is removed, and the sentence in line172 to 175 is modified.

Point 5: Some figures or letters are missing in lines 196 and 197, the same than in the line 213. Replace the words "Assumption" per "Hypotesis" in lines 219 and 221, and it should be added an "s" in the word "order" in the line 221.

Response 5: We are grateful to your suggestion that improved our manuscript greatly. Missing formulas are added in line233-237. In line 260 and 263, we replaced the words "Assumption" with "Hypotesis", and added an "s" in the word "order" in the line 260.

Point 6: The meaning of the variables should be placed just after each equation where variables are mentioned, and not all listed in one sheet. This will clarify the understanding of the reader.

Response 6: We are grateful to your suggestion that improved our manuscript greatly. We updated the manuscript by explaining related variables after each equation.

Point 7: The meaning of some variables as ， ，and  is not mentioned in the text.

Response 7: We are grateful to your suggestion that improved our manuscript greatly. We explained ，  in line 305-306, and explained in line 303.

Point 8: Define what is "h" in the equation 5...

Response 8: We are grateful to your suggestions that improved our manuscript greatly. We are sorry for this editing error, the correct symbol is added in the equation 5.

Point 9: "i" is the origin of the road segment but also the number of customers. Please review.

Response 9: This comment is very valuable.  represents the customer point set;  represents the set of road segments. We updated the manuscript by revising similar errors.

Point 10: In the equation 3, the limits of index "i" and "k" are the same ("N"). Please review.

Response 10: Thanks for the valuable comment. We are sorry for this editing error, The correct statement is    We updated the manuscript by revising some errors.

Point 11: In the equation 3, magnituds are not coherent beacuse  is representing the carbon emissions "per unit of time" and the other adding terms are not "per unit of time". Please review..

Response 11: Thanks for the valuable comment and suggestion. We have carefully corrected the errors,  represents the carbon emissions of each delivery vehicle, which is modified in line 311.

Point 12: Please correct the word "re-detects" in the line 305.

Response 12: Thanks for the valuable comment and suggestion. We updated the manuscript by revising this word. We are so sorry for this spelling error.

Point 13: Add a reference linked to the "Topcuoglu's theory".

Response 13: This comment is very valuable. We updated the manuscript by adding references linked to Topcuoglu theory

Point 14: Please explain what "Popsize" (line 379) and "Maxgen" (line 381) is conceptually representing. Consider that readers of the paper must not be experts in MATLAB.

Response 14: Thanks for the valuable comment and suggestion. Popsize represents population size and Maxgen represents the maximum number of iterations, We updated the manuscript by explaining "Popsize" and "Maxgen" in line 449-451.

Point 15: Please review the sentence from line 381 to 386 for the justification of  and  selection.

Response 15: This comment is very valuable. We updated the manuscript by explaining how to set the weight coefficients of parameter  and .

Point 16: It seems that Table 2 is Table 1 and Table 2 (mentioned in line 385) is in fact missing.

Response 16: Thanks for the valuable comment and suggestion. We updated the manuscript by adding the missing formula and Table 1 is modified.

Point 17: In the presentation of the experimental case is said that "there are 10 homogeneous vehicles" (line 372), however in the results showed in "Table 3" only 4 vehicles are mentioned. Please review.

Response 17: This comment is very valuable. 10 homogeneous vehicles are the total number of vehicles. In this experiment, only 4 vehicles were used, and others are non-use vehicles.

Point 18: In the "Table 4", units for "costs" and "carbon emissions" are missing.

Response 18: This comment is very valuable. We updated the manuscript by adding units for "costs" and "carbon emissions" in Table 3.

Point 19: Please review the lines 422 and 423 where is said that "Although the carbon emissions are large, the cost is the smallest.", because according to the "Table 4", both carbon emissions and costs are smaller in the centralized decition-making mode.

Response 19: Thanks for the valuable comment and suggestion. We updated the manuscript by. modifying the conclusion.

Point 20: CONCEPTUAL improvements:

In the Section 5.- "Multilevel genetic algorithm design" and Section 6.- "Experimental analysis", It should be clearer to the reader the process of chromosomes and genes assignment and how the crossover, mutation and repairing is made on them. This is very slightly mentioned in the text and in a very general way. It is required to be more specific there and how this is applied to the experimental case. This will help a lot to understand how figures 4 and 5 in the section 6 are achieved. In the current status they are quite confussing.

Response 20: Thanks for the valuable comment and suggestion. We updated the manuscript by. modifying section 5 and adding figures to understand section 6.

Point 21: In the Section 1-Introduction or in the Section 2- Literature review, a justification of the method selected to solve the problem should be introduced. The optimization of routes from a distance perspective (which is linked to carbon emissions) can be also addressed by other methods different to genetic algorithms. For instance, ant colony optimization algorithms for the Travelling Salesman Problem.

Response 21: Thanks for the valuable comment and suggestion. We updated the manuscript by rewriting Section 1 and Section 2, and explained the reason for choosing the multilevel genetic algorithm.

Point 22: About the CONCLUSION: This section should be extended addressing a deeper discussion about the problem, the selection of the method, its limitations, the achieved results and what further developments should be addressed in future studies to continue with this research line.

Response 22: Thanks for the valuable comment and suggestion. We updated the manuscript by. revising section 7 and discussed the problem, the selection of the method, its limitations and further developments in future studies

Author Response File: Author Response.docx

Round 2

Reviewer 2 Report

Dear Authors,

Thanks so much for considering all my comments. However, there are still some minnor points which need to be improved:

• In the line 29 the sentence "We will conduct in-depth research on..." should be replaced by "Further research should be addressed on...."
• When there is only one author, the cittation "Hall et al." must not be used, because there is not any other authors, you should only citate as "Hall". And when you have 2 authors, you should citate as "Erik and Anna", and never "Erik et al."
• In the Equation 3, the definition of E^f_M is missing. In fact, the definition of each variable linked to an equation should be written just below each equation in order to improve the understanding by the readers. This means: Eq. 1, then description of variables involved in Eq. 1, Eq. 2, then description of variables involved in Eq. 2, etc...
• In the Equation 10, the range of "j" for the first term is not defined, and the interpretation of this equation "indicates that the vehicle must leave after completing the distribution task" needs some clarification, because this is not well understood.
• Remake lines 375 to 379 in a more understandable way.
• Figures 4, 5, 6, 7, 8 and 9, and Table 2 are not referred in the text. 
• Please, mention explicitly in the manuscript, when you refer to the table 2, that only 4 vehicles among the 10 available are being considered in the study.
• In figures 4 and 5, please clarify the reason because some times the parent is called "Parent" and others as "Progeny". If there is not reason, please harmonize the nomenclature.
• In figure 6, the second group of parents (just before Step 1) is exactly the same than the first group of parents (top part of the figure). It seems an error, otherwise, please clarify.
• Define what is "C" in the line 457. Perhaps it should be E^max, and provide units to the number "700".

Thanks very much in advance for considering all these comments. 

Author Response

Response to Reviewer 1 Comments

Point 1: In the line 29 the sentence "We will conduct in-depth research on..." should be replaced by "Further research should be addressed on...."

Response 1: Thanks for the valuable comment and suggestion. According to your valuable suggestions, we have carefully revised your mentioned mistakes.

Point 2: When there is only one author, the cittation "Hall et al." must not be used, because there is not any other authors, you should only citate as "Hall". And when you have 2 authors, you should citate as "Erik and Anna", and never "Erik et al.".

Response 2: Thanks for the valuable comment. We have carefully revised your mentioned mistakes and carefully recheck the whole paper to revise similar mistakes.

Point 3: In the Equation 3, the definition of EfM is missing. In fact, the definition of each variable linked to an equation should be written just below each equation in order to improve the understanding by the readers. This means: Eq. 1, then description of variables involved in Eq. 1, Eq. 2, then description of variables involved in Eq. 2, etc...

Response 3: This comment is very valuable. We have carefully corrected the errors, represents the manufacturer's fixed carbon emissions per unit time, which is modified in line 296. We have modified the format that the definition of each variable linked to each equation is written below each equation.

Point 4: In the Equation 10, the range of "j" for the first term is not defined, and the interpretation of this equation "indicates that the vehicle must leave after completing the distribution task" needs some clarification, because this is not well understood.

Response 4: Thanks for the valuable comment and suggestion. We defined the range of "j" in line 326, and We updated the manuscript by interpreting this equation.

Point 5: Remake lines 375 to 379 in a more understandable way.

Response 5: We are grateful to your suggestion that improved our manuscript greatly. We modified lines 385 to 394 to make it easier to understand.

Point 6: Figures 4, 5, 6, 7, 8 and 9, and Table 2 are not referred in the text.

Response 6: Thanks for the valuable comment and suggestion. We updated the manuscript by revising your mentioned mistakes.

Point 7: Please, mention explicitly in the manuscript, when you refer to the table 2, that only 4 vehicles among the 10 available are being considered in the study.

Response 7: We are grateful to your suggestion that improved our manuscript greatly. We explained the usage of the vehicle in line 495-498.

Point 8: In figures 4 and 5, please clarify the reason because some times the parent is called "Parent" and others as "Progeny". If there is not reason, please harmonize the nomenclature.

Response 8: We are grateful to your suggestions that improved our manuscript greatly. We updated the manuscript by revising figure 4 and figure 5 in order to better understand the relationship between parents and progeny. Parent will generate progeny after crossover operator, mutation operator, etc.

Point 9: In figure 6, the second group of parents (just before Step 1) is exactly the same than the first group of parents (top part of the figure). It seems an error, otherwise, please clarify.

Response 9: This comment is very valuable. We updated the manuscript by modifying Figure 6.

Point 10: Define what is "C" in the line 457. Perhaps it should be Emax, and provide units to the number "700".

Response 10: Your suggestions are so kind to point out the mistakes of this work. We are really sorry for the careless mistakes. According to your valuable suggestions, we have carefully revised your mentioned mistakes in line 466.

Author Response File: Author Response.docx