Integrating Digital Twins of Engineering Labs into Multi-User Virtual Reality Environments

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper presents a novel approach to enhancing engineering education through the integration of digital twins and multi-user virtual reality. The study is well-structured, using the DSRM to guide the development and evaluation of the proposed VR tool. The introduction clearly outlines the limitations of traditional engine laboratory practices and effectively positions the research within the context of Industry 4.0. The methodology is detailed, describing the steps taken to sensorize the engine, establish communication between the physical setup and the virtual environment, and create the multi-user VR experience. The comparison between traditional and VR-based experiences further strengthens the argument for the adoption of this technology. However, there are some areas that could be improved:

1) While the paper mentions the use of specific technologies, it could benefit from a more in-depth discussion of the technical challenges encountered and the solutions implemented. For example, details on the specific algorithms used for data synchronization or the optimization techniques employed for the VR environment would enhance the paper's technical contribution.

2) The survey focuses primarily on student satisfaction. While this is important, including objective measures of learning outcomes (e.g., test scores, project performance) would provide a more comprehensive evaluation of the VR tool's effectiveness.

3) Some of the references in the reference list are not formatted properly.

4) The conclusion acknowledges some limitations, such as the visual quality of the virtual environment. Expanding on these limitations and suggesting future research directions would strengthen the paper.

5) More discussions are needed for the digital twinning technology and its role in Industry 4.0. In the introduction/literature review (especially section 1.2), the authors only discussed about the role of digital twins in real-time analysis and decision making. However, digital twins provide much more critical functionalities than that. Digital twins also facilitate real-time process monitoring and real-time-updated process forecasting, which are important to highlight as well. I recommend a read at this paper to improve the discussion on digital twinning and industry 4.0 more (https://doi.org/10.3390/s24154852)

 

Author Response

Global point: This paper presents a novel approach to enhancing engineering education through the integration of digital twins and multi-user virtual reality. The study is well-structured, using the DSRM to guide the development and evaluation of the proposed VR tool. The introduction clearly outlines the limitations of traditional engine laboratory practices and effectively positions the research within the context of Industry 4.0. The methodology is detailed, describing the steps taken to sensorize the engine, establish communication between the physical setup and the virtual environment, and create the multi-user VR experience. The comparison between traditional and VR-based experiences further strengthens the argument for the adoption of this technology. 

Global response:

Point 1: While the paper mentions the use of specific technologies, it could benefit from a more in-depth discussion of the technical challenges encountered and the solutions implemented. For example, details on the specific algorithms used for data synchronization or the optimization techniques employed for the VR environment would enhance the paper's technical contribution.

Response 1: Thank you for your feedback. I have added a discussion in lines 443–449 to address the technical challenges encountered and the solutions implemented. This section now includes details on data synchronization and the optimization techniques used for the VR environment. Additionally, I have included a new image that better reflects the project in Unity, making the technical aspects more evident. Please let me know if there are any further improvements you would suggest.

Point 2: The survey focuses primarily on student satisfaction. While this is important, including objective measures of learning outcomes (e.g., test scores, project performance) would provide a more comprehensive evaluation of the VR tool's effectiveness.

Response 2: Thank you for your valuable suggestion. This study was primarily focused on developing a practical tool to support learning, rather than replacing the existing activity. For this reason, the evaluation centered on student satisfaction and engagement as initial indicators of its effectiveness. However, we recognize the importance of incorporating objective measures of learning outcomes, such as exam performance or project results, to provide a more comprehensive assessment. To address this, we have added a section in the conclusions outlining future work, specifically in lines 471–473, where we propose conducting further research to analyze the tool’s direct impact on student learning and knowledge retention through measurable academic performance indicators.

Point 3: Some of the references in the reference list are not formatted properly.

Response 3: Thank you for pointing that out. I have reviewed the reference list, and the formatting issues with references 12, 41, and 43 have been corrected to comply with the required citation style. I appreciate your careful review, and I hope these adjustments address the concern.

Point 4: The conclusion acknowledges some limitations, such as the visual quality of the virtual environment. Expanding on these limitations and suggesting future research directions would strengthen the paper.

Response 4: Thank you for your valuable comments. In response, I have expanded the conclusion by further detailing the limitations, such as the visual quality of the virtual environment, and suggesting future research directions

5) More discussions are needed for the digital twinning technology and its role in Industry 4.0. In the introduction/literature review (especially section 1.2), the authors only discussed about the role of digital twins in real-time analysis and decision making. However, digital twins provide much more critical functionalities than that. Digital twins also facilitate real-time process monitoring and real-time-updated process forecasting, which are important to highlight as well. I recommend a read at this paper to improve the discussion on digital twinning and industry 4.0 more (https://doi.org/10.3390/s24154852)

Response 5: Thank you for your valuable suggestion. I have expanded the discussion on digital twinning technology in the introduction, particularly in section 1.2, to include its broader functionalities. In addition to its role in real-time analysis and decision-making, I have highlighted its importance in real-time process monitoring and real-time updated process forecasting. The paper you recommended has been reviewed and cited to strengthen the discussion on digital twinning and its connection to Industry 4.0.

Reviewer 2 Report

Comments and Suggestions for Authors

This study introduces a multi-user virtual reality (VR) tool designed to enhance hands-on learning in engineering education by integrating real-time sensorized digital twins. There are some comments as follows.

1. The motivation and novelty of this paper is not clear in abstract.

2. Generally, authors introduce the background at the beginning of the introduction. It is suggested that authors enhance the background and improve the logic of introducing related works.

3. As the background of this paper includes real-time sensing and IoT, recent high quality works should be introduced, and should focuse on the real-time constraint of the IoT.

4. The contributions of few references are introduced in detail. Authors need to compare the contributions of this paper and those of references to highlight the novelty.

5. Authors introduce real-time sensing and real-time communication, more details and their relationship should be provided.

6. The writing of this paper should be revised and improved, it is not appropriate to state that “To solve the problems mentioned above, a renovated laboratory is proposed,” The problems mentioned above should be specific.

7. Besides，“As shown in Figure 3.” Is not a complete sentence.

8. Figures, such as figure 5 and figure 9, should be revised for clarity and readability.

9. Important results and findings should be better summarized in conclusion.

Comments on the Quality of English Language

The writing of this paper should be revised and improved

Author Response

Global Point: This study introduces a multi-user virtual reality (VR) tool designed to enhance hands-on learning in engineering education by integrating real-time sensorized digital twins. There are some comments as follows.

Point 1: The motivation and novelty of this paper is not clear in abstract.

Response 1: Thank you for your comment. We have revised and improved the abstract to better clarify the motivation and novelty of the study. In the updated version, we emphasize the limitations of traditional laboratory teaching methods, such as time constraints and limited access to equipment, which motivate this research. Additionally, we highlight the novelty of integrating virtual reality and digital twins into a collaborative learning environment, offering an interactive and safe learning experience that complements both theoretical and practical teaching. We believe these changes make the key aspects of our research clearer.

Point 2: Generally, authors introduce the background at the beginning of the introduction. It is suggested that authors enhance the background and improve the logic of introducing related works.

Response 2: Thank you for your valuable feedback. We have incorporated additional information from the cited papers to enhance the background and improve the logical flow of introducing related works in the introduction

Point 3: As the background of this paper includes real-time sensing and IoT, recent high quality works should be introduced, and should focuse on the real-time constraint of the IoT.

Response 3: Thank you for your suggestion. We have added a Unity image to better illustrate the programming aspects related to real-time sensing and IoT, providing a clearer understanding of the real-time constraints in our implementation

Point 4: The contributions of few references are introduced in detail. Authors need to compare the contributions of this paper and those of references to highlight the novelty.

Response 4: Thank you for your observation. We have added a detailed comparison between the contributions of this paper and those of the referenced works in the discussion section to better highlight the novelty of our study

Point 5: Authors introduce real-time sensing and real-time communication, more details and their relationship should be provided.

Response 5: Thank you for your feedback. Additional information about the real-time communication process has been included, detailing the data flow, signal processing in Node-RED, and the transmission protocol used to ensure low-latency synchronization with Blynk and Unity

Point 6:  The writing of this paper should be revised and improved, it is not appropriate to state that “To solve the problems mentioned above, a renovated laboratory is proposed,” The problems mentioned above should be specific.

Response 6: Thank you for your feedback. We have revised the statement to make it more specific regarding the problems addressed. Additionally, we have included the specific objectives of the proposal, which can be found in section 3.1.1

Point 7: Besides，“As shown in Figure 3.” Is not a complete sentence.

Response 7: Thank you for your feedback. We have revised the sentence to make it complete, and now it reads: 'In Figure 3, the setup of the sensing system, motors, and VFD is shown

Point 8: Figures, such as figure 5 and figure 9, should be revised for clarity and readability.

Response 8: Thank you for your feedback. We have enlarged the figures and adjusted the font size to improve clarity and readability

Point 9. Important results and findings should be better summarized in conclusion

Response 9: Thank you for your valuable feedback. The conclusion has been revised, and the key results and findings have been summarized more clearly. I hope this has addressed your concern respectfully

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have provided a robust response to comments, alongside revised the paper well. I can now recommend paper acceptance.

Reviewer 2 Report

Comments and Suggestions for Authors

Authors have addressed my previous comments.