Round 1

Reviewer 1 Report

Review Report Manuscript applsci-1987837

 

Manuscript Number: applsci-1987837

Type of manuscript: Project Report

Title: Reliability Enhancement Driven by ANN for Lighting Control System in Highway Tunnels

Journal: Applied Sciences

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Dear Colleague,

 

I read with great interest your article entitled "Reliability Enhancement Driven by ANN for Lighting Control System in Highway Tunnels". Your article is well written and very interesting. I congratulate you for this work,

 

I read with great interest your article entitled "Reliability Enhancement Driven by ANN for Lighting Control System in Highway Tunnels". This subject is of growing interest with the appearance of LED lighting, its low energy consumption and above all its ease of adaptation to different environments and of dimming.

There are nevertheless certain points which it would be desirable to correct, improve or complete.

 

In this paper, you consider color temperature as an additional parameter in an ANN data processing architecture not previously studied in tunnel studies. It's OK. Nevertheless, in this specific context linked to road lighting, of which tunnel lighting is a part, I would like to draw the authors' attention to the fact that one of the priorities on the road is also to maintain extreme vigilance and attention. Regarding the color temperature, it plays an essential role since cold white light (with a strong spectral part in blue) blocks the production of melatonin (sleepiness molecule) by the pineal gland which prevents sleep. In this case, on the roads, the best color temperature can only be cold white light for safety reasons because it prevents sleep.

 

 

Please take the necessary steps to correct or revise the following points in your article:

 

Abstract:

 

- “to alleviate physical and mental discomfort”: What kind of physical discomfort? Mental discomfort? These terms lack precision. I suggest to replace this by “visual discomfort”. Here, in the abstract, it’s not necessary to develop this but after, you can speak about eye adaptation, glare, flickering, etc...

 

 

Page 1:

 

In your introduction, you present the article in the unique context of an application in your country. Your article will be published in an international journal, it would be interesting to also give other examples and cite other reference articles such as:

 

Doulos, L.T.; Sioutis, I.; Tsangrassoulis, A.; Canale, L.; Faidas, K. Revision of Threshold Luminance Levels in Tunnels Aiming to Minimize Energy Consumption at No Cost: Methodology and Case Studies. Energies 2020, 13, 1707. https://doi.org/10.3390/en13071707

 

Peña-García, A. (2022). Sustainable tunnel lighting: One decade of proposals, advances and open points. Tunnelling and Underground Space Technology, 119, 104227.

 

to show that if the application of your work is important for your country, it is also applicable and important generally throughout the world.

 

Page 2:

 

“... but need a moment to adjust”: undefined statements should be avoided. Here, it would be necessary to put a duration of adaptation of the human eye and a reference.

 

Page 3:

 

“Furthermore, these two factors mental and visual...”: "mental" is unclear, you used the term "psychological" just before, it would be better to use it again here to talk about stress.

“This synergy clearly appears in some of the most common disturbing effects in

tunnels. ». « Most common disturbing effects » : can you add in parenthesis some examples in order to be clearer.

 

« The research of tunnel lighting system mainly includes two aspects, the evolution and control modes of lighting sources and the overall architecture of lighting control system. »

 

If I well understand, I count 3 aspects which are developped just after inside the 3 following paragraphs :

2.1 Evolution of tunnel lights (« evolution » in the sentence)

2.2 Progress of tunnel lighting control system (« control modes » in the sentence)

2.3 Key requirements of tunnel lighting system (about « overall architecture »)

 

Thus, the sentence should be modified as : « The research of tunnel lighting system mainly includes three aspects: the evolution of tunnel lights, the control modes of lighting sources and the overall architecture of lighting control system. »

 

End of paragraph 2.1 « service life » : the term is correct but lifetime (or lifespan) is more appropriate. If you can modify that. Thanks

 

Page 4

 

In the table 2:

 

« Lifespan of LED lights is about 100,000H under ideal conditions » 

Lifespan of HPSL or fluorescent is only 10,000H.”

 

A lifespan of 50,000 hours is more realistic. Ideal conditions for an LED are dry air with sub-zero temperatures to dissipate heat and prevent moisture and oxidation. In addition, the LED lighting power supplies are their weak point. It is better to find a reliable and recent reference and cite it. In general, for professional products, realistically, lifetimes are around 50 to 70,000 hours. On the other hand, concerning the latest generation fluorescent lamps, the lifetime is of the order of 30,000 hours.

 

It seems to me that there is an inconsistency to check (where did you find this data? Are they recent? You should put a reference): LED street lights have two categories: with separate ballasts and (unfortunately) sometimes with an integrated ballast. The latter is very difficult to repair and the lifetime corresponds to the average time between failure.

Knowing that an LED luminaire consists of an electronic ballast and a light source, the MTBF of 20,000 hours can only concern the ballast, which is particularly low.

Either your figures relate to products of very poor quality, or these figures are wrong and should come very close to the lifespan of LED light.

Can you check this, please. Thanks

 

« illuminance (0~100%) » : better to write « illuminance dimming (0~100%) ».

 

 

“More than 85% of the luminous flux reaches the ground. » : LED luminaires are extremely directional and 100% of the light emitted goes in the direction of the ground. Then there may be reflection from the ground to the sky.

Can you correct this or explain? Does this 85% correspond to the light sent by the luminaire? If so, how can 15% go skyward with this kind of directional fixture? Or, does this 15% correspond to an amount of light due to the average reflection of a road?

 

Section “others” : “Environmentally friendly”.

 

it's not that simple and it's not possible to write it that way. The only light source that is truly "environmentally friendly" is one that does not exist and has not been manufactured.

But you can write more "environmentally friendly" than an incandescent lamp (or an HPS lamp) for example. To be more accurate, it would be necessary to cite articles on life cycle analyzes (see K. Bertin et al for example: Bertin, Kévin, et al. "Life cycle assessment of lighting systems and light loss factor: A case study for indoor workplaces in France." Electronics 8.11 (2019): 1278.). An LED lamp has a much greater impact on the environment during its manufacture, but its long lifespan and low consumption compared to other types of lamps means that over its entire lifespan, it is less impactful.

 

So, you can add a reference and change terms to something relative like “more environmentally friendly than other light sources”

 

« HPSL is being replaced LED in large scale » : “HPSL is being replaced by LED light sources in large scale”

 

Paragraph 2.2:

 

What do you mean by “progress of LED lighting theory » ? Isn't it rather "technology" or "engineering"? Because about theory (light emission by a LED), there is no evolution since decades.

 

Page 6

 

Paragraph 3.1

 

Probably small typo problem with space before the word “which”: “maintenance stage ， which

 

Page 13 :

 

After having defined the parameters, it would be very useful, for more clarity, to make a diagram of the ANN integrating these various parameters and the various interactions between the inputs and the outputs.

P17 :

 

In figure 4 you compare the results between the measurements and the simulation. FIG. 5 makes it possible to associate this drop in luminance with the change in color temperature. How do you explain this shift of about 0.25 down the two curves between 25:00 and 48:00 in luminance?

 

Little typo in the conclusion before “Also due to its attribute of continuous » : erase the underline character

 

 

 

You have developed a method to automate luminance and color temperature adjustments via ANN. Your work is very interesting. The main objective is to improve visual comfort. How did you feel this one was better? It is easy to measure energy consumption by presenting figures and the energy savings made, but concerning visual comfort, how can you estimate it?

 

You claim that your work will improve the reliability of LED lights in tunnels but you give no value. it is assumed that improved reliability is the consequence of longer life and less failure but you don't give any estimate on that. Could you, in your conclusion, answer the problem that you announce in your title in a numerical way? You say it improves reliability without demonstrating it.

 

 

 

 

Review Report Conclusion

 

Overall, this article is well written, well-structured and innovative. Nevertheless, the results announced on the reliability rests on the assumption that the system, managed by an algorithm, will be more reliable than if it had been it by the experiment and the human know-how. This last point needs to be clarified in a formal and non-hypothetical way.

 

In general, this publication could be of interest to be published after some revisions.

 

Comments for author File: Comments.pdf

Author Response

Please see the attachment "Response to Reviewer 1 Comments.docx".

Thanks a lot.

Author Response File: Author Response.docx

Reviewer 2 Report

The article presents an interesting and important problem of matching lighting levels in a tunnel. The problem of tunnel illumination is a difficult issue due to the matching of drivers' adaptation levels to visual conditions. The problem of tunnel illumination is generally related to the daytime, associated with the long adaptation time of the driver's eyesight to the low luminance levels in the tunnel entrance zone in relation to the luminance of the road in front of the tunnel.

Comments:
1. The problem of driver adaptation in daytime and nighttime conditions is not clearly described. These are different adaptation curves and this needs to be clarified in the article.
2. Please supplement in the article with graphics of the required change in luminance level in the tunnel as a function of its length.
3. The method of determining the luminance of the roadway in front of the tunnel, the entrance portal and the interior of the tunnel is not described. Was the measurement done with a matrix camera, with what standards, what were the luminance levels ?
4. The method of measuring the color temperature in front of and inside the tunnel was not described.
5. Please describe (preferably by drawing ) the required change in luminance levels in the threshold and transition zones of the tunnel at nighttime (graph as a function of time).
6. Please explain the reasons for using dynamic color temperature change. It is not clear why this is done and how this change can affect driver behavior.
7. What driving factor is affected by this change in color temperature?
8. The problem of glare and flicker has not been addressed - please signal these problems.
9. The review of world and european literature is poor - please add to the current items.

Author Response

Please see the attachment "Response to Reviewer 2 Comments.docx"

Author Response File: Author Response.docx