Agent-Based In-Vehicle Infotainment Services in Internet-of-Things Environments

Round 1

Reviewer 1 Report

Please check the attached file. 

Comments for author File: Comments.pdf

Author Response

This paper presents a new scheme for In-Vehicle Infotainment (IVI) services, called, agent-based IVI (A-IVI) to address the communication degradation of the centralized IVI (C-IVI) while the number of users and devices increase. The proposed scheme is implemented in a testbed, and it is found to reduce transmission delay, increase throughput, and decrease master’s loads. Please make following revisions as below:

 

Q1. The motivation of proposed strategy need clarification between Line 51-56. It would be helpful to give an example of real applications that the C-IVI does not do a good job. Clarification is also desired to quantically describe when we can use C-IVI, and when should not.

A1. Based on the comments, we first added the corresponding description in Section 1. For example, in case of a brand-new autonomous car, there may be many users and a wide variety of IVI devices, such as smart phones, speakers, music/video players, heaters, air conditioners, navigation, lights, head-mount displays, seats, and so on. If these devices are used by many users at the same time, a large amount of traffics will be generated, and this may induce the performance degradation in the C-IVI system.

As for the quantitative description about when we can use C-IVI, and when should not, we added the corresponding description in Section 6 (conclusions). From the experimental results, we can see that the proposed A-IVI scheme provides better transmission delays and throughput performance than the existing peer-to-peer and C-IVI schemes, in particular, in case that there are ten or more IVI devices in the vehicle.

Thank you for the valuable comments and suggestions.

 

Q2. Similar to previous comment, it would be beneficial to clarify the IVI systems in Table 1. For example, how many users/devices will each of these IVI systems approximately have? Do they use A-IVI? Can their system support C-IVI?

A2. Thank you for the valuable comments. As per the comment, the corresponding description is added in Section 2.1 of the revised paper. The current IVI systems provide many distinctive services with user-friendly interfaces for easy management. On the other hand, most of the current IVI systems are based on the peer-to-peer or C-IVI models, since there are small number of IVI devices, at most ten, in the system. Google [15] and Apple [16] partially support the C-IVI system. However, the A-IVI system has not been deployed yet.

 

Q3. Figure 3 need to be adjusted to reflect direct communication between users and agents.

A3. According to the suggestion, Figure 3 was updated. Thanks for the comment.

 

Q4. Does the direct/indirect communication consider ACK/NACK? If the message delivery fails, e.g., WIFI connection breaks, how does the C-IVI deal with?

A4. Thanks for the valuable comment. In this paper, we do not address the error control issue for message loss and recovery in the network, since the underlying protocol, such as CoAP, can provide its own error control mechanisms by using the CoAP CON method [9, 10].

The corresponding description is given in Section 3.3.2 of the revised paper.

 

Q5. What are the criteria to choose direct or indirect communication?

A5. Thanks for the valuable comments. The use of indirect and direct communications may be determined by the type of data to be contained in the message. For example, we may use indirect communication for delivery of mission-critical or control data, since the associated information needs the permission of IVI master, whereas general user data, such as multimedia contents, may be delivered by using the direct communication.

The corresponding description is given in Section 3.3.2 of the revised paper.

 

Q6. In Section 4, please describe the details of implementation setup, e.g., software/environment. Where do the Figure 17-21 come from?

A6. Thanks for the very valuable comments. Based on the comment, we give the detailed description on testbed network configuration, implementation setup, and the associated software development, together with the corresponding references. The performance evaluation and packet capture analysis by Wireshark are all done based on the real implementation and testbed experimentation (not simulation) in the paper.

The corresponding description is given in Section 4 and 5 of the revised paper.

 

Q7. Please describe the details of setup for each test result in Section 5.2, 5.3 and 5.4. For example, in Section 5.2, how many devices are configured in Figure 24?

A7. As per the comments, more detailed description on how to get the performance analysis results, including the number of users, APs and devices employed for experimentation, is given in Section 5. Thanks for the valuable comments.

 

Q8. The results in Section 5.2-5.4 need more clarification. Why the test all starts from 10 in all of the figures in these sections? Does the C-IVI outperform A-IVI if number of users are smaller than 10 in Figure 24? Another confusion is about the range of users/devices. Is it possible that we will have 100 users or 100 devices that communicate to each other at the same time?

A8. Thanks for the valuable comments. Based on the comment, the corresponding texts are revised. For example, in Figure 24, the number of IVI devices is fixed to 30, whereas different number of IVI users are compared. In Figure 25, the number of IVI users is fixed to 20, whereas different number of IVI devices are compared. In each figure, 10 or more users or devices are employed for performance analysis, since almost the same performance are given for 10 or less users and devices. This implies that the proposed agent-based IVI scheme does not give performance gains for small scales of users and devices.

In conclusion, the proposed agent-based A-IVI scheme can be used effectively for the IVI systems with large number of users and devices, as shown in the public transportation, such as train or airplanes. However, in the IVI systems with small number of users and devices, such as car, the proposed scheme tends to provide almost the same performance with the existing C-IVI scheme. For further study, a more enhanced scheme needs to be developed for the IVI systems with small number of users and devices by exploiting the features of the proposed A-IVI scheme and the characteristics of IVI devices.

The corresponding description is given in Section 5 as well as in abstract and conclusion sections of the revised paper. Thanks so much again for the valuable comments.

 

Q9. The following editorial changes are required.

- Please move the full name of CoAP from Line 98 to Line 63.

- Please use “data usage” in Line 151.

- In Section 3.3.2, please use “direct communication” instead of “direction communication”

- Please explain “AP” in Line 424.

A9. As per the comments, the concerned texts are all corrected in the revised paper. We believe that the paper has been much more enhanced, with the help of those numerous valuable comments and suggestions. Thanks so much again.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper is a good piece of work and would be interesting for other researches in this field. In any case, I suggest the following points in order to improve the manuscript.

Question 1:

The introduction is clear and all the objectives well stated. At the same time,  suggest to increase the state of the art providing a paragraph talking about the possibilities of IoT, maybe this could be a good reference to frame the work:

Hassija, V., Chamola, V., Saxena, V., Jain, D., Goyal, P., & Sikdar, B. (2019). A survey on IoT security: application areas, security threats, and solution architectures. IEEE Access, 7, 82721-82743.

Question 2:

The paper can be improved in terms of analytical model. Explain a little bit more in details what are the advantages/disadvantages of your proposal.

Question 3:

The paper could be improved in terms of application examples to other situations. I would suggest to create a small paragraph by considering such applications and explaining how you can use your proposal for them. I would suggest to include some strategy to monitor the status of the driver, taking into account the irruption of biomonitoring devices that can provide easily this information to other users of the car. This way, you could easily add data collected by smartbands like Heart Rate and so, and improve the security on board. The possibilities of this smart devices have been recently studied in the eHealth field.

Rodríguez-Rodríguez, I., Rodríguez, J. V., & Zamora-Izquierdo, M. Á. (2018). Variables to be monitored via biomedical sensors for complete type 1 diabetes mellitus management: An extension of the “on-board” concept. Journal of diabetes research, 2018.

Question 4:

I  really like the addition of Raspberry Pi. Have considered the possibility of computing some data in this Pi? maybe some fog-computing ideas could be introduced.

Question 5:

Please highlight the limitations of your proposal. Future improvements/works could have been more discussed. Please increase this point.

 

Author Response

The paper is a good piece of work and would be interesting for other researches in this field. In any case, I suggest the following points in order to improve the manuscript.

 

Q1: The introduction is clear and all the objectives well stated. At the same time, suggest to increase the state of the art providing a paragraph talking about the possibilities of IoT, maybe this could be a good reference to frame the work:

Hassija, V., Chamola, V., Saxena, V., Jain, D., Goyal, P., & Sikdar, B. (2019). A survey on IoT security: application areas, security threats, and solution architectures. IEEE Access, 7, 82721-82743.

A1: Thank you for the valuable comment. As per the comment, the corresponding discussion is added in Section 1 of the revised paper, with the associated references [7].

 

Q2: The paper can be improved in terms of analytical model. Explain a little bit more in details what are the advantages/disadvantages of your proposal.

A2: The proposed agent-based A-IVI scheme can be used effectively for the IVI systems with large number of users and devices, as shown in the public transportation, such as train or airplanes. However, in the IVI systems with small number of users and devices, such as car, the proposed scheme tends to provide almost the same performance with the existing C-IVI scheme.

The corresponding description is given in Section 5 as well as in abstract and conclusion sections of the revised paper. Thanks so much again for the valuable comments.

 

Q3: The paper could be improved in terms of application examples to other situations. I would suggest to create a small paragraph by considering such applications and explaining how you can use your proposal for them. I would suggest to include some strategy to monitor the status of the driver, taking into account the irruption of biomonitoring devices that can provide easily this information to other users of the car. This way, you could easily add data collected by smartbands like Heart Rate and so, and improve the security on board. The possibilities of this smart devices have been recently studied in the eHealth field.

Rodríguez-Rodríguez, I., Rodríguez, J. V., & Zamora-Izquierdo, M. Á. (2018). Variables to be monitored via biomedical sensors for complete type 1 diabetes mellitus management: An extension of the “on-board” concept. Journal of diabetes research, 2018.

A3: Thanks for the valuable suggestions. Based on the suggestion, the corresponding texts are added to Section 1 of the revised paper, with the associated references [8].

 

Q4: I really like the addition of Raspberry Pi. Have considered the possibility of computing some data in this Pi? maybe some fog-computing ideas could be introduced.

A4: In our experimentation, Raspberry Pi was used as IVI user, IVI agent, and IVI device, and thus the Pi performs the data processing functionality, as described in Section 4. Thanks also for the comment on the fog-computing technology. The fog-computing concepts can also be used to enhance our proposed scheme. Thus, the corresponding description is added in the conclusion section of the revised paper for further study items.

 

Q5: Please highlight the limitations of your proposal. Future improvements/works could have been more discussed. Please increase this point.

A5: Based on the comments, the paper was revised. The proposed agent-based IVI scheme does not give performance gains for small scales of users and devices (e.g., 10 or less users/devices). Instead, the proposed scheme can be used effectively for the IVI systems with large number of users and devices, as shown in the public transportation, such as train or airplanes. For further study, a more enhanced scheme needs to be developed for the IVI systems with small number of users and devices by exploiting the features of the proposed A-IVI scheme and the characteristics of IVI devices.

The corresponding description is given in Section 5 as well as in abstract and conclusion sections of the revised paper.

We believe that the paper has been much more enhanced, with the help of those numerous valuable comments and suggestions. Thanks so much again.

 

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The authors replies sufficiently addressed my comments.