A Simulated Annealing for Optimizing Assignment of E-Scooters to Freelance Chargers

Round 1

Reviewer 1 Report (New Reviewer)

The paper concerns the optimization of the assignment of e-scooter to freelance charges by using a metaheuristic approach.

 Major issues

In the abstract, citations should be avoided. In any case they must be consistent with the guidelines of the journal

The citations within the article are made inconsistently, alternating author and year and number of the article in the bibliography. In any case they must be consistent with those indicated in the guidelines of the journal.

It would be appropriate to separate the state of the art from the introduction.

In the first part of eqn. 1, it seems that x_kjk and x_jkk should be always equal to 1 since charger k belongs to both the arcs since they represent the arcs used to pick-up and deliver the scooter from / to the charger. If it is not so, please clarify better.

The described algorithm seems to implement a standard annealing procedure; the innovation introduced is not clearly specified. Please specify better what innovations have been introduced.

No considerations about the stability of the algorithm seem to have been made.

The interpretation of Fig. 5 is not very clear. It would seem that simulated cases and those deduced from practice differ by several orders of magnitude.

 

Minor issues

In the text, the terms Tab. and Table are used to identify the figures. Calls should be standardized. Furthermore, in one case (Table 2 in page 11) the text is formatted as a caption.

Table format should be improved. It would be appropriate to report tables 3 and 4 in an appendix and summarize results in the text. In any case, from the current format, it is not immediate to refer the results to the cities.

It would be better to represent the algorithm in a figure rather than a table; furthermore it should be written in a pseudo-code format and described within the paper.

 

Author Response

Hi, please find the attached response letter form reviewer 1.

Author Response File: Author Response.docx

Reviewer 2 Report (New Reviewer)

Topic: A simulated Annealing for Optimizing Assignment of E-Scooters to Freelance Chargers

Abstract: First and last-mile trips are becoming increasingly expensive and detrimental to the environment, especially within dense cities. Thus, new micro-mobility transportation modes such as e-scooter sharing systems have been introduced to fill the gaps in the transportation network. Furthermore, some recent studies examined the e-scooters as a green option from the standpoint of environmental sustainability (Hollingsworth et al., 2019) and (Moreau et al., 2020). Currently, e-scooter charging is conducted by competitive freelancers who do not con-sider the negative environmental impact resulting from not optimizing the fuel efficiency of their charging trips. Several disputes have been recorded among the freelance chargers, espe-cially when arriving at an E-scooters location simultaneously. The paper aims to find the optimal tours for all chargers to pick up e-scooters in the form of routes, such that each route contains one charger, and each e-scooter is visited only once by the set of routes, which are typically called an E-Scooter-Chargers Allocation (ESCA) solution. This study developed a mathematical model for the assignment of e-scooters to freelance chargers and adapted a simulated annealing metaheuristic to determine a near-optimal solution. We evaluated the proposed approach using real-world instances and a benchmark-simulated dataset. Moreover, we compared the proposed model benchmark dataset to the baseline (i.e. state-of-practice), where the data is available at (M. Dell’Amico, 2014) and (M. Dell’Amico, 2016). The results showed a reduction of approximately 61%−79% in the total distance travelled, lead-ing to shorter charging trips.

 

Comments:

 1) Introduction:

Dear authors, in the introduction on lines 43-45 you made the statement that electric scooters lead to a reduction in carbon dioxide emissions. Please read the work: https://doi.org/10.3390/en15218188 and complete your statement.

In addition, the work should systematize the literature record - once it is written in the form [], and another in ().

In addition, the literature review of the article is at a low level.

 2) Problem statement and formulation: 

Chapter 2.1. it should contain some introduction so that the reader can find out what is presented below.

 3) SA framework and 4) The SA-based assignment algorithm: 

I recommend combining these two chapters (3 and 4).

Please let me know if the Authors modified any of this algorithm? Is it just the use of a ready-made algorithm for the Authors' research? So what is the research novelty of the authors?

 5) Computational experiments.

The results are presented concisely and correctly.

 6) Discussion and Conclusion.

This chapter is only a conclusion. A separate discussion section should be added and the results obtained should be related to those of other authors. This is an essential section that must be included in the article.

 

Author Response

Hi, please find the attached response letter for reviewer 2.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report (New Reviewer)

No further suggestions

Reviewer 2 Report (New Reviewer)

Dear Authors,

Unfortunately, your manuscript still needs revision:

- a description of further research directions should be included in the summary.

- discussion section - should contain information on the results obtained in relation to other scientists' research - this is missing and needs to be supplemented.

- moreover, the discourse section is more like a conclusion than a discussion.

Regards

Author Response

Response to Reviewer 2

 Comment 1

A description of further research directions should be included in the summary.

Response 1

 Thank you for your comment. Future directions have been included from Lines 445 to 458.

Comment 2

- Discussion section - should contain information on the results obtained in relation to other scientists' research - this is missing and needs to be supplemented.

 

Response 2

Thank you for your comment.

The results obtained in relation to other scientists' research have been added in the discussion section, please see Lines 388 to 404. Also, Table 5 has been included to compare SA with BHO, ACA, and MILP.

 

 Comment 3

- Moreover, the discussion section is more like a conclusion than a discussion.

 

Response 3

Thank you for your comment.

The discussion section has been improved from lines 377 to 412.

 

Author Response File: Author Response.docx

Round 3

Reviewer 2 Report (New Reviewer)

Thank you for the corrections, the article is ready for publication in its current form.

Regards

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

This paper is entitled “A simulated Annealing for Optimizing Assignment of E-Scooters to Freelance Chargers”. This study developed a mathematical model for the assignment of e-scooters to freelance chargers and adapted a simulated annealing metaheuristic to determine a near-optimal solution. In this case, the idea and results of the paper are interesting but the following comments can be utilized to improve this paper.

 

Abstract: First and last-mile trips are becoming increasingly expensive and detrimental to the environment, especially within dense cities. Why?

Abstract: the aim and objective of the paper must be elaborated.

Abstract: the process of data collection and collected data must be describe in brief.

Page1. Line35: U.SA Furthermore, what is the U.SA?!

Page1, Line 43-45: “Freelance chargers spend significant time searching for e-scooters because of the competitive nature of the profession and the inaccuracy of the location-finders of some e-scooters”: I suggest that the authors describe additional information about competitive business factors among Freelance chargers.

Page1, line44: Authors must use references from scientific papers instead of website or news. I suggest finding appropriate paper for this case.

Page1, line43, 54, 58: similar comment like above about finding scientific paper. Otherwise, this citation is not appropriate.

Page2, line 5: Authors must utilize papers from published one. Unpublished papers are not acceptable for the citation.

Authors did not provide a comprehensive literature review for this paper. I have two suggestion and they can use one of the. First, add more literature related to this work including their objectives, methods and results in the introduction. Second, Authors must add a new part entitld “literature review” and provide related review based on this manuscript. The second one is more acceptable.

Page3, line130: “In the ESCA solution approach, the six charged e-scooters are returned to a single 130 position, and hence the solution does not the redistribution of the charged e-scooters.” Why is it written in the different color?!

Page5, Formula1: Authors must described in details how they provide this objective function. If they establishe it, it must be described, if it is from other references, it must be cited. Now, it is not clear.

Page5, line 164 authors must describe first what is the meaning of “inbound direction equals the outbound direction”: why do they utilize his constraint for the optimization?!

Formula4: It needs to consider and check whether it is correct or not.

Page8, line252: Authors make sure caption of the figure 2 is exactly under the figure in page 7 not page8.

 

 

Final decision: The idea and objective of this paper are interesting. The structure of the paper is suitable and it can be published after major revision based on the above comments. 

Comments for author File: Comments.pdf

Author Response

Please find the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

The manuscript addresses an optimization problem to assign e-scooters to free-lance chargers and fully describes the modelling procedure. 

Although interesting, this is totally out of scope for a journal called "sustainability", whose readership expects to find a full description of the environmental and social (for example) implications and impacts from these operations, and not just the algorithm description.

Moreover, no literature review to help understand the problem (for example, free-lance chargers are unknown in many European cities), no clear research question, no results discussion, poor conclusions (look like a proxy of the manudcript summary). Referencing not in the journal style; glossary not reported. Unfit. 

Author Response

Please find the attached file.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors answer all the comments.

Author Response

Thank you !

Reviewer 2 Report

Aside from adding few references, the authors did nothing to develop and elaborate any specific content strictly related to sustainability topics, as specifically requested. The manuscript, lacking this quality, can be hardly of interest for the readership of a journal called "sustainability". Totally unfit for publication

Author Response

The manuscript ahs been updated according to the reviewer's comments.

Author Response File: Author Response.docx