Simulation Study on an ICT-Based Maritime Management and Safety Framework for Movable Bridges

Round 1

Reviewer 1 Report

The manuscript “Simulation Study on an ICT based Maritime Management and Safety framework for Movable Bridges” presents a theoretical framework and simulation of an intelligent water vehicle management system for movable bridges corresponding to vehicle traffic responses. The topic of the paper is very interesting, considering also the strategic importance of the movable bridges.
The paper is well organized and the results are clearly discussed in the text. 
Only minor improvements are suggested

• improve the quality of the Figures
• check the tables editing 

Author Response

Dear Editor of Applied Sciences,

Thank you so much for giving us an opportunity to significantly improve our paper according to the reviewers’ comments. 

With regard to the suggestion on “Moderate English changes required”, we have done our best to polish the English writing through the help of a native Australian speaker (i.e., Jack Pinnow) who is also the co-author.  

The following are how we respond to address the reviewers’ comments. 

Many thanks,

Shi Qiang Liu et al. 

Reviewer 1:  The manuscript “Simulation Study on an ICT based Maritime Management and Safety framework for Movable Bridges” presents a theoretical framework and simulation of an intelligent water vehicle management system for movable bridges corresponding to vehicle traffic responses. The topic of the paper is very interesting, considering also the strategic importance of the movable bridges.  The paper is well organized and the results are clearly discussed in the text. Only minor improvements are suggested

Response: Thank you so much for your positive assessment. 

Comment 1: improve the quality of the Figures

Response: Thanks so much for your constructive comment. Accordingly, we have improved Figures 6-7 and enlarged Figure 8-13 in the revised manuscript. 

Comment 2: Check the tables editing

Response: Thanks. We have checked the tables editing. The improved tables can be found in the revised manuscript. Especially, we have clarified the Algorithm 1 and edited the format of Table 1.

Reviewer 2 Report

This manuscript is a simulation study examining an emergency collision avoidance control system for the safe operation and operation of a movable bridge with heavy traffic. This is the development of a movable bridge safety management system, which can be said to be the optimal intersection system for marine and land traffic, in order to safely operate and control the moving traffic of ships and vehicles related to the movable bridge without accidents. It seems to be indispensable in the modern infrastructure management society. Reviewers are familiar with structural mechanics research, but not experts in transportation systems such as infrastructure operations and operations. Therefore, I would like to comment and comment on the basics from the reader's point of view.

1. Regarding the introduction of the treatise, there is no doubt about the automation of system operation consisting of alarms and cameras / sensors because of the need for safe operation of movable bridges. In particular, automatic detection and warning systems are indispensable for devices and the like for avoiding danger. Before we dive into the topic of system considerations in Chapter 2, it would be nice to have a little systematic summary of those basic safety concepts and ideas.

2. In the counting algorithm, the flowchart in Fig. 3 is very difficult to understand, partly because the control system is large. First, for the purpose of anti-collision associated with the basic, first movable bridge system,
Readers should have a relationship diagram that gives an overview of collision factors, such as the relationship between the three control elements of a ship, a bridge, and a vehicle, as well as warning signals associated with different speed systems, operating time and navigation time for closing, restraining, and machine operation. Easy to understand.

3. Since it is difficult to distinguish the movable bridges, routes and roads in Fig. 1,2,5,6,7,8,9,10 with a black background, it is better to change the background color of the bridges and roads to white. The distinction between land and sea is also clear. If the vehicle can be colored colorfully, I think it's better to improve it. In addition, the symbols for routes AB and CD in the figure are a little difficult to read, so it is better to clearly indicate A and B in the figure. The scales of the distance position, velocity, and acceleration graphs in the lower figure of each figure cannot be read.

4. If you are advocating a safety management algorithm based on the remaining number of vehicles and ships passing before and after passing the movable bridge, what should you do if the remaining number check is due to some kind of error? When it comes to software management using electrical energy, what kind of measures should be taken when alerts do not work due to a power outage? I think it is necessary to think robustly.

5. This time we are focusing on a specific movable bridge (Fort Madison Swing Bridge), but I think it would be better if a general safety control system was designed for various elemental parameters elsewhere.

Author Response

Reviewer 2:  This manuscript is a simulation study examining an emergency collision avoidance control system for the safe operation and operation of a movable bridge with heavy traffic. This is the development of a movable bridge safety management system, which can be said to be the optimal intersection system for marine and land traffic, in order to safely operate and control the moving traffic of ships and vehicles related to the movable bridge without accidents. It seems to be indispensable in the modern infrastructure management society. Reviewers are familiar with structural mechanics research, but not experts in transportation systems such as infrastructure operations and operations. Therefore, I would like to comment and comment on the basics from the reader's point of view.

Response: Thank you very much for your positive remarks. 

Comment 1: Regarding the introduction of the treatise, there is no doubt about the automation of system operation consisting of alarms and cameras / sensors because of the need for safe operation of movable bridges. In particular, automatic detection and warning systems are indispensable for devices and the like for avoiding danger. Before we dive into the topic of system considerations in Chapter 2, it would be nice to have a little systematic summary of those basic safety concepts and ideas.

Response:  Thanks for your constructive suggestion.  We agree with your comment that having a short systematic summary on the basic safety concepts and ideas and on the overall system will help the readers to dive deeper into the system consideration. For this purpose, we have added a new section named ‘System Components’ after the introduction before going into the ‘System Consideration’. In addition, in the introduction section, we have also added two more references to compare the sensor and advanced technologies in on-road vehicles and maritime technologies. 

Comment 2: In the counting algorithm, the flowchart in Fig. 3 is very difficult to understand, partly because the control system is large. First, for the purpose of anti-collision associated with the basic, first movable bridge system, Readers should have a relationship diagram that gives an overview of collision factors, such as the relationship between the three control elements of a ship, a bridge, and a vehicle, as well as warning signals associated with different speed systems, operating time and navigation time for closing, restraining, and machine operation. Easy to understand.

Response: Thank you for your constructive comment. In order to explain the flowchart in Figure 3 (in the original manuscript), we have added a new section (Section 2 in the new manuscript). In addition, we have added a new figure (Figure 5) to show the relationship between the communication flow and control system in Section 4. The new diagram comprehensively coordinates the control elements of the ships, bridges and vehicles with corresponding warning signals. We expect that these modifications will help the readers to better understand the concepts through reading the new section and new figures that will smooth the transition of information.  

Comment 3: Since it is difficult to distinguish the movable bridges, routes and roads in Fig. 1,2,5,6,7,8,9,10 with a black background, it is better to change the background color of the bridges and roads to white. The distinction between land and sea is also clear. If the vehicle can be colored colorfully, I think it's better to improve it. In addition, the symbols for routes AB and CD in the figure are a little difficult to read, so it is better to clearly indicate A and B in the figure. The scales of the distance position, velocity, and acceleration graphs in the lower figure of each figure cannot be read.

Response: We are grateful to the honorable reviewer for your constructive suggestions. For this suggestion, however, it is really difficult for us to change the black background because the original diagram was directly obtained from our self-generated simulation environment. Instead, to better illustrate the diagram, we have added a new image (Figure 1) to clarify the system components without relying on the graphical interfaces. Moreover, in the methodology section, we have enlarged the images so that the scales of the distance position, velocity, and acceleration graphs in the lower portion of the figures are visible. We hope that these changes make the paper comprehensible while the black background has to be kept. 

Comment 4: If you are advocating a safety management algorithm based on the remaining number of vehicles and ships passing before and after passing the movable bridge, what should you do if the remaining number check is due to some kind of error? When it comes to software management using electrical energy, what kind of measures should be taken when alerts do not work due to a power outage? I think it is necessary to think robustly.

Response:  We agree with the honorable reviewer’s comment that it might be a serious issue in the system if the software management is hampered due to the lack of electrical energy. The proposed system is based on buoys, which is considered to be self-powered from solar panels and energy storage systems to power up the DC circuits in case of emergency situations such as bad weathers. The ship control systems have their energy storage systems already present in the system. However, the control systems of the bridge and traffic bollard units need to have a backup power for maintaining the software system since the components are closely related to the safety of the system and people. A backup power based on renewable energy can be employed at the bridge and traffic control system, which will energize the DC circuits such as the microcontroller unit for calculating the data. Thus, we have updated section 6 by adding a new paragraph to address your comments in detail. 

Comment 5: This time we are focusing on a specific movable bridge (Fort Madison Swing Bridge), but I think it would be better if a general safety control system was designed for various elemental parameters elsewhere.

Response:  Thanks. We would like to clarify that, although a generalized structure and safety control system for the movable bridges over the world has been attempted for presentation, the Fort Madison Swing Bridge is considered for the sole purpose of simulation and case analysis. Typical setup has been presented with some redundant components in the research (such as cameras) so that only the required components can be chosen for the implementation of the same system for different movable bridges. We have made efforts to highlight specific changes to generalize the elemental parameters in the revised manuscript. The contribution of this study has been clearly mentioned at the beginning of the methodology section. A new section (Section 2) and some new figures have been added in this revision. Specific focus and feasibility studies on other movable bridges will be identified as the future work in the result and discussion section.