Simulation of Low Carbon Layout Optimization of Disassembly Line Based on SLP Method
Round 1
Reviewer 1 Report
The redesign of the layout based on low carbon criteria could be an interesting topic, but from my point of view, the paper has too many problems to be considered for publication.
Some of the most important are:
1. The title uses the word “optimization”, but the main tools used to solve the problem defined, SLP methodology and simulation, are not tools for optimization purposes. For example, the three different layouts, in the SLP methodology, are generated using a heuristic method. In my opinion, one of the most interesting aspects of the paper that could have been mentioned in the title is the combination of SLP and simulation, but I don’t know exactly the novelty level of it because we don’t have a deep review of papers about this.
2. Precisely, this is a second important issue. The literature review carried out in the introduction section (from line 62 to 109) could be more focused because, in the first half (from line 62 to 77), papers about reverse logistics network are reviewed. Why “network”? Are really the network or the supply chain aspects interesting to this paper? If yes, how? About the rest of the works reviewed (the second half, from line 77), I am not very sure about how they contribute to the paper.
3. In my opinion, a section to explain and justify the methodology used to solve the problem is needed. Above all, when the SLP methodology is not explained.
4. At the end of the introduction section, the two contributions of the paper are explained. The first one is the analysis of the current situation. It is said that the study investigates the general layout of disassembly lines in current reverse logistics processing centers and their advantages and limitations and analyzes them systematically, but I think that this investigation is missing, and also the advantages and limitations of the general layout of disassembly lines in current reverse logistics processing centers. The second one is the design of an optimal layout but, as I said in the first point, by using SLP an optimal solution cannot be assured (in the last sentence of this second contribution it is said that the study allows to arrive at the optimal solution). For these reasons, the only two contributions of the papers are some weak.
5. In the problem statement section, two sets of problems are enumerated; the first one is about dismantling process problems and the second one is about the line layout but, since the process and the layout are strongly correlated (i.e., a change in the process usually impacts in the layout), several problems are repeated, adding confusion to the text. Furthermore, from my point of view, a reflection on cause-effect should be made to better identify the problems (effect).
6. In section 3, “optimization” objectives are proposed but, in my opinion, these objectives are correlated, because by reducing transfer distance you will also reduce pollution. In the same way, with more effective use of the area, you can also reduce pollution. Therefore, have we a single objective? to reduce pollution? Will it be achieved by reducing the transfer distance (whose? Operators, vehicles, both…?).
7. At the beginning of section 3.1, it is said that: “Before using the SLP analysis method for layout, the elements of the disassembly line need to be analyzed …” but this sentence is not justified and therefore, not very well understood. Why is important the analysis of these five elements? In fact, this elements analysis shouldn’t be made “before” using SLP, but as the first stage of SLP methodology. I think this mistake is due to the SLP methodology has not been presented.
8. It is not explained how the three layout proposals fulfil or cover the relations shown in figure 6. Neither nothing is said about the different sizes of the box of a specific section among the proposals, for instance, the disassembly area box is different in each layout proposal.
9. …
Furthermore, there are a lot of minor problems that made the work difficult to follow such as:
a) in line 172, three types of parts are mentioned (“… three types of dismantled parts, …”) but they have not been explained previously, what are exactly the differences between reusable and recyclable parts?
b) in figure 2, It seems you want to represent the process but some boxes like “disassembly area” are not really stages of the process,
c) in table 3, there are classification and testing areas but, in table 4, it appears some new areas called inspection, storage, repair and parts warehouse without explanation, is table 4 made from table 3 (as you indicate in lines 312-314)?
d) in figure 4, the relation between maintenance area (3) and parts library (7) is O/5, but the legend box only explains until 4,
e) some numbers are not too easy to understand to me, for example, the ones used in formulas (3) and (4), why is used the daily storage and the average number of days of storage of goods to calculate the area? Don´t you need to consider the maxim quantity of goods storage or a forecast of this quantity to dimension the area for this quantity? and
f) in the simulation model, why (10, 0) for the Poisson distribution (by the way, revise possible duplicate word).
g) …
Author Response
Response to Reviewer 1 Comments
Point 1: The title uses the word “optimization”, but the main tools used to solve the problem defined, SLP methodology and simulation, are not tools for optimization purposes. For example, the three different layouts, in the SLP methodology, are generated using a heuristic method. In my opinion, one of the most interesting aspects of the paper that could have been mentioned in the title is the combination of SLP and simulation, but I don’t know exactly the novelty level of it because we don’t have a deep review of papers about this.
Response 1: Thank you very much for your suggestion. The main purpose of the optimization we apply here is to improve the original plan layout of the disassembly line, and to better highlight the novelty, we have rewritten the contribution and novelty of the article in the introduction.
Point 2: Precisely, this is a second important issue. The literature review carried out in the introduction section (from line 62 to 109) could be more focused because, in the first half (from line 62 to 77), papers about reverse logistics network are reviewed. Why “network”? Are really the network or the supply chain aspects interesting to this paper? If yes, how? About the rest of the works reviewed (the second half, from line 77), I am not very sure about how they contribute to the paper.
Response 2: Thank you very much for your suggestion. We have rewritten the literature review as a whole. Reverse logistics, logistics operation area layout, and layout methods are the three aspects of the literature review.
Point 3: In my opinion, a section to explain and justify the methodology used to solve the problem is needed. Above all, when the SLP methodology is not explained.
Point 7: At the beginning of section 3.1, it is said that: “Before using the SLP analysis method for layout, the elements of the disassembly line need to be analyzed …” but this sentence is not justified and therefore, not very well understood. Why is important the analysis of these five elements? In fact, this elements analysis shouldn’t be made “before” using SLP, but as the first stage of SLP methodology. I think this mistake is due to the SLP methodology has not been presented.
Response 3,7: Thank you very much for your suggestion, we have added a flow chart of the basic steps of the SLP method in the method discussion section. The flowchart is used to explain the argumentation of the SLP method.
Point 4: At the end of the introduction section, the two contributions of the paper are explained. The first one is the analysis of the current situation. It is said that the study investigates the general layout of disassembly lines in current reverse logistics processing centers and their advantages and limitations and analyzes them systematically, but I think that this investigation is missing, and also the advantages and limitations of the general layout of disassembly lines in current reverse logistics processing centers. The second one is the design of an optimal layout but, as I said in the first point, by using SLP an optimal solution cannot be assured (in the last sentence of this second contribution it is said that the study allows to arrive at the optimal solution). For these reasons, the only two contributions of the papers are some weak.
Response 4: Thank you very much for your suggestion and we are rewriting the contribution section of the article.
Point 5: In the problem statement section, two sets of problems are enumerated; the first one is about dismantling process problems and the second one is about the line layout but, since the process and the layout are strongly correlated (i.e., a change in the process usually impacts in the layout), several problems are repeated, adding confusion to the text. Furthermore, from my point of view, a reflection on cause-effect should be made to better identify the problems (effect).
Response 5: Thank you very much for your suggestion For the problem you mentioned that several questions were repeated, resulting in confusing text, we have rewritten the section.
Point 6: In section 3, “optimization” objectives are proposed but, in my opinion, these objectives are correlated, because by reducing transfer distance you will also reduce pollution. In the same way, with more effective use of the area, you can also reduce pollution. Therefore, have we a single objective? to reduce pollution? Will it be achieved by reducing the transfer distance (whose? Operators, vehicles, both…?).
Response 6：Thank you very much for your suggestions. In this paper, the layout of the dismantling line is optimized to reduce CO2 emissions and reduce environmental pollution. The CO2 emissions generated by forklifts during the transfer driving process account for the largest share of the total emissions of the dismantling line.
Point 8: It is not explained how the three layout proposals fulfil or cover the relations shown in figure 6. Neither nothing is said about the different sizes of the box of a specific section among the proposals, for instance, the disassembly area box is different in each layout proposal.
Response 8: Thank you very much for your suggestion. Due to various influences such as the epidemic during the study, we gave the basic layout of the plan, we only gave the overall area of the area and no specific size limit. In future studies, we will focus on this point and make further improvements based on it.
Furthermore, there are a lot of minor problems that made the work difficult to follow such as:
Point a: in line 172, three types of parts are mentioned (“… three types of dismantled parts, …”) but they have not been explained previously, what are exactly the differences between reusable and recyclable parts?
Response a: Thank you very much for your advice. After deeper reflection, we have decided to remove this section.
Point b: in figure 2, It seems you want to represent the process but some boxes like “disassembly area” are not really stages of the process,
Response b：Thank you very much for your suggestion. In the figure, we give a before and after comparison of the optimization of the disassembly line operation in the logistics center, and we think that in Figure 2 each square is one of the important processes that cannot be missing.
Point c: in table 3, there are classification and testing areas but, in table 4, it appears some new areas called inspection, storage, repair and parts warehouse without explanation, is table 4 made from table 3 (as you indicate in lines 312-314)?
Response c: Thank you very much for your correction, we are very sorry for the confusion caused by the English writing and we have corrected them in the tables.
Point d: in figure 4, the relation between maintenance area (3) and parts library (7) is O/5, but the legend box only explains until 4,
Response d: Thank you very much for your correction, we have made changes to the picture.
Point e: some numbers are not too easy to understand to me, for example, the ones used in formulas (3) and (4), why is used the daily storage and the average number of days of storage of goods to calculate the area? Don´t you need to consider the maxim quantity of goods storage or a forecast of this quantity to dimension the area for this quantity? and
Response e: Thank you very much for your suggestion. We think that a calculation using the number of goods stored in each area would be representative.
Point f: in the simulation model, why (10, 0) for the Poisson distribution (by the way, revise possible duplicate word).
Response f: Thank you very much for your suggestion. In the model, this is a randomness, using a probability distribution arrival interval. The most important customer arrival process is called Poisson arrival process.
Thanks again for your comments. Changes in the text are highlighted with yellow markers.
Author Response File: 
Author Response.docx
Reviewer 2 Report
The abstract and the paper are unnecessarily long. More than a third of each should be removed.
The paper does not present innovative ideas but it uses standard techniques that can benefit practitioners and graduate students.
The paper used layout option, scheme and program to mean the same thing. Please stick to layout option.
The vector W is not defined properly in p24.
Do not use 4.2, use Section 4.2
What are the values of m and n in Eqn (6)
What is delta in Eqn (9)
What is f'_i0 in (8)
i_max j_max should be max_i max_j
In the marked copy, I highlighted some words and sentences that are either wrongly chosen or need explanation.
Some references are not needed. There are 7 references for Flexsim. I believe 1 or 2 are sufficient.
Reference 16 and 18 have the same content. Use one of them.
References 4 to 7 are not needed.
References 36, 37 and 38 are not cited in the text.
Author Response
Response to Reviewer 2 Comments
Point 1: The abstract and the paper are unnecessarily long. More than a third of each should be removed. Response 1: Thank you very much for your suggestion. We have rewritten the abstract and trimmed it, as well as trimming the content of the article.
Point 2: The paper does not present innovative ideas but it uses standard techniques that can benefit practitioners and graduate students.
Response 2: Thank you very much for your suggestion. We have rewritten the article in the introduction section for novelty as well as contributions.
Point 3: The paper used layout option, scheme and program to mean the same thing. Please stick to layout option.
Response 3: Thank you very much for your correction, which we have made in the original paper.
Point 4: The vector W is not defined properly in p24.
Response 4: Thank you very much for your suggestion, we have changed it in the corresponding position.
Point 5: Do not use 4.2, use Section 4.2
Response 5: Thank you very much for your suggestion, for 4.2, this appears in the section heading, which is the format shown by the formatting template in the journal.
Point 6: What are the values of m and n in Eqn (6)
Response 6：m is the number of the reference series and n is the number of the comparison series.
Point 7: What is delta in Eqn (9)
Response 7: I'm sorry, but we don't see the "delta" you have mentioned in the paper, probably due to versioning or other issues.
Point 8: What is f'_i0 in (8)
Response 8: Thank you very much for your advice. I think it may be a Word version issue, we are seeing it in the form of a formula in the manuscript.
Point 9: i_max j_max should be max_i max_j
Response 9: Thank you very much for your suggestion, but we think it appears in the formula and should be kept in its original form.
Point 10: In the marked copy, I highlighted some words and sentences that are either wrongly chosen or need explanation.
Response 10：Thank you very much for the correction, we have corrected the writing of the whole paper.
Point 11: Some references are not needed. There are 7 references for Flexsim. I believe 1 or 2 are sufficient.
Response 11: We have rearranged this section of references.
Point 12: Reference 16 and 18 have the same content. Use one of them.
Response 12: We have removed reference 18.
Point 13: References 4 to 7 are not needed.
Response 13: We have abridged these references.
Point 14: References 36, 37 and 38 are not cited in the text.
Response 14: Since we have rewritten the literature review section, we have rechecked all the literature.
Thanks again for your comments. Changes in the text are highlighted with yellow markers.
Author Response File: Author Response.docx
Reviewer 3 Report
- The abstract needs to be improved. The first sentence in the abstract, it is necessary for the authors to add a sentence to describe the problem or motivation to focus on this topic.
- In the Introduction that brings up a number of findings from different areas without linking them together.
- There is no flow in the text. It partly depends on the lack of proofreading but also on the fact that many statements and claims are made without being followed up by a clear and logical discussion.
- Please reason both the novelty and the relevance of your paper goals. Clearly discuss what the previous studies that you are referring to. What are the Research Gaps/Contributions? Please note that the paper may not be considered further without a clear research gap and novelty of the study.
- In the introduction, you need to connect the state of the art to your paper goals. Please follow the literature review by a clear and concise state of the art analysis. This should clearly show the knowledge gaps identified and link them to your paper goals.
- What implication can be referred to? The above questions should be answered. Authors need to propose their study.
- Literature Review has the chance to be further improved: it seems that the authors have made the retrospection. However, via the review, what issues should be addressed? Please address the these papers: 2022. A New Wooden Supply Chain Model for Inventory Management Considering Environmental Pollution: A Genetic algorithm. Foundations of Computing and Decision Sciences and 2017. A decentralized supply chain planning model: a case study of hardboard industry. The International Journal of Advanced Manufacturing Technology. What is the current specific knowledge gap with comparing these papers?
- Figure 2 is not clear
- I recommend strengthening the comparison with previous research. Please compare the results in this study with those in previous studies. Discuss the study findings here. The discussion and conclusion are appropriately written and require no changes.
- Basically, you should enhance your contributions, limitations, underscore the scientific value added of your paper, and/or the applicability of your findings/results and future study in this session. The discussion is relatively simple and insufficient.
- Why is it timeliness to explore such a study? What makes this study different from the previously published studies? Are there any similarly findings in line with the previously published studies? Are the findings different from prior academic studies that were conducted elsewhere, if any?
- I would like to request the author to emphasize the contributions practically and academically in the implication session.
Author Response
Response to Reviewer 3 Comments
Point 1: The abstract needs to be improved. The first sentence in the abstract, it is necessary for the authors to add a sentence to describe the problem or motivation to focus on this topic.
Response 1: Thank you very much for your suggestion. We have rewritten the abstract as a whole.
Point 2: In the Introduction that brings up a number of findings from different areas without linking them together.
Response 2: Thank you very much for your suggestion, we have rewritten the literature review section in the introduction as a whole. And after the end, we have analyzed and compared the previous literature with this paper to highlight the innovation and necessity of this research.
Point 3: There is no flow in the text. It partly depends on the lack of proofreading but also on the fact that many statements and claims are made without being followed up by a clear and logical discussion.
Response 3: Thank you very much for your suggestion, we have proofread the article as a whole and hope to improve it.
Point 4: Please reason both the novelty and the relevance of your paper goals. Clearly discuss what the previous studies that you are referring to. What are the Research Gaps/Contributions? Please note that the paper may not be considered further without a clear research gap and novelty of the study.
Point 5: In the introduction, you need to connect the state of the art to your paper goals. Please follow the literature review by a clear and concise state of the art analysis. This should clearly show the knowledge gaps identified and link them to your paper goals.
Point 6: What implication can be referred to? The above questions should be answered. Authors need to propose their study.
Point 9: I recommend strengthening the comparison with previous research. Please compare the results in this study with those in previous studies. Discuss the study findings here. The discussion and conclusion are appropriately written and require no changes.
Point 11: Why is it timeliness to explore such a study? What makes this study different from the previously published studies? Are there any similarly findings in line with the previously published studies? Are the findings different from prior academic studies that were conducted elsewhere, if any?
Response 4, 5, 9: Thank you very much for your suggestion. The analysis of previous literature reviews and the comparison with this paper have been added after the literature review to highlight the research differences and novelty of the article. And we have rewritten the main contribution part of the article.
Point 7: Literature Review has the chance to be further improved: it seems that the authors have made the retrospection. However, via the review, what issues should be addressed? Please address the these papers: 2022. A New Wooden Supply Chain Model for Inventory Management Considering Environmental Pollution: A Genetic algorithm. Foundations of Computing and Decision Sciences and 2017. A decentralized supply chain planning model: a case study of hardboard industry. The International Journal of Advanced Manufacturing Technology. What is the current specific knowledge gap with comparing these papers?
Response 7: Thank you very much for your suggestion, we have analyzed the two articles you mentioned in the literature review section. We have rewritten the literature review section and added a comparative analysis.
Point 8: Figure 2 is not clear
Response 8: Since the picture are too large, we show them separately in order to make them more clearly.
Point 10: Basically, you should enhance your contributions, limitations, underscore the scientific value added of your paper, and/or the applicability of your findings/results and future study in this session. The discussion is relatively simple and insufficient.
Response 10：Thank you very much for your suggestion. At the end of the introduction we have rewritten the contribution of this article. In the conclusion section, we added possible limitations of the article and its future applicability.
Point 12: I would like to request the author to emphasize the contributions practically and academically in the implication session.
Response 12: The authors highlight the practicality of the study by researching a specific disassembly line layout optimization with Company H. The innovation through the combination of SLP and Flexsim has academic contribution.
Thanks again for your comments. Changes in the text are highlighted with yellow markers.
Author Response File: Author Response.docx
Reviewer 4 Report
There are no comparisons with the work in literature.
Author Response
Response to Reviewer 4 Comments
Point 1: There are no comparisons with the work in literature.
Response 1: Thank you very much for your suggestion. The analysis of previous literature reviews and the comparison with this paper have been added after the literature review to highlight the research differences and novelty of the article. And we have rewritten the main contribution part of the paper.
Thanks again for your comments. Changes in the text are highlighted with yellow markers.
Author Response File: Author Response.docx
Round 2
Reviewer 3 Report
Good work
