Joint Optimization of Inventory and Repositioning for Sea Empty Container Based on Queuing Theory

Round 1

Reviewer 1 Report

The paper seems very interesting. It describes a real example of the queueing theory application.  From the introduction, it is clear that the empty containers problem is in great demand and scientists use completely different approaches for it solving.  Although the Sea Engineering terminology makes me some difficulties, I read the paper with pleasure. I have some minor comments for authors:

l In literature overview, there is not any reference devoting queueing theory.

l The authors casually talk about self-used containers on S.148-149.  As I know, in my country there are two types of containers - common and private. And we can optimize only common ones. Private containers must be serviced and moved according to the contract.

l In my opinion, part of text devoting the batch arrivals can confuse the readers because of the using model has not batches.

Typos:

l S. 107 queueing process - > queueing system

l S. 251 i ->t

l S.370 DesigN

l S.427 extra line break

l S.458 Fig 3 -> Fig 5

l S. 545 to solve the mathematical model - >to solve optimization problem

 

In future study, I recommend to consider queuing system with batch arrivals and batch service.

Author Response

请参阅附件。

Author Response File: Author Response.docx

Reviewer 2 Report

1- The abstract should contain the most important outcomes of the research. In addition to this, some quantitative findings can be added to this section

2- Why did you use empty container repositioning problem?

3-   How utilized the outcomes?

4- please , explain in more details why you used queuing theory to handle the uncertain  supply and demand of empty containers ? is it possible to choose another method?

5- cite all the equations you are not derived.

6- why the time interval between the arrival of empty containers in container supply ports is a negative exponential distribution?

7- Include a nomenclature

8- the authors states "a birth and death process diagram of  empty container inventory in the queuing system is constructed to better calculate the probability of empty container inventory status in the queuing system" can you give the reasons?

9- The mathematical model need to be cited by reference. 

10- can you solve the mathematical model by a different method and compare the results with the genetic algorithm 

11-  The "Conclusion" section should be enriched by adding some ""quantitative outcomes"".

 Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.docx