The Quality Control System of Green Composite Wind Turbine Blade Supply Chain Based on Blockchain Technology
Round 1
Reviewer 1 Report
In this paper, a quality control system based on blockchain technology is developed to improve the operation of the green composite wind turbine blade supply chain. The framework of this system is designed and the product quality can be examined and verified by regulator, and be monitored by other related nodes. The hash fingerprint is used for data storage helps to reduce the transaction fee. The system tests are carried out to prove its validity. The topic is of significance the manuscript is well organized. A few questions should be answered before possible publication.
- Intheintroduction, authors provide the traditional green composite wind turbine blade supply chain in Fig.1, they should summarize its main problem without blockchain technology.
- In Section 2.1, what type of the hash fingerprint is used in the system? Providingmore details about Fig.2.
- In Section 2.2, the structure of the wallet is similar to HD wallet, they authors shouldexplain the difference between HD wallet and proposed wallet.
- In Section 2.3, Fig.5 illustrates the on-chain dataprocess, however, the content of this paragraph is not clear enough, rewrite Fig.5 to make it more readable.
- In Section 3.1, based on the data provided in Fig.7, it is concluded that the hash fingerprint form can reduce the transaction fee compared with the original form. With more numbers of characters, the more cost is observed by original form. What is the cost of the transaction fee when using more number of characters?
- In Section 3.3, it is seen that the traceability process of information is found in Ethereum browser as shown in Fig.10. Theon-chain information can be traced by transaction hashesand a certain block height. We note that the history record is also stored in smart phones, does the smart phone also record the information via transaction hash and a certain block height?
- The languageshould be polished by native speakers.
Author Response
Response to Reviewer 1 Comments
Point 1: In the introduction, authors provide the traditional green composite wind turbine blade supply chain in Fig.1, they should summarize its main problem without blockchain technology.
Response 1: Thank you for the comment. The traditional green composite wind turbine blade supply chain is illustrated in Fig.1, however, the main problem may be not clearly enough, so we add a figure 2 to better conclude the main problem existing in present supply chain, and the challenge in this field is also given to highlight the problem in supply chain, so as to make the problems solved by blockchain more clearly. The paper is revised in page 1 line 77.
Point 2: In Section 2.1, what type of the hash fingerprint is used in the system? Providing more details about Fig.2.
Response 2: Thank you for the comment. To illustrate the hash fingerprint of the proposed system, we clarify it in page 6 line 216:
“The information stored on blockchain may cause high transaction fee when the data volume is too large, thus, the fingerprint (FP) form of the information is designed to deal with this situation in on chain process. The actual upload data is in the form of the original hash fingerprint information of the string data. Through the comparison of fingerprint information, we can ensure that the original information is correct and cannot be tampered. In this design, the fingerprint information is calculated by SHA256+RIPEMD160, and we will further discuss this method in the section 3.3.”
Point 3: In Section 2.2, the structure of the wallet is similar to HD wallet, the authors should explain the difference between HD wallet and proposed wallet.
Response 3: Thank you for the comment. According to the suggestion, we have added some explanations as shown below in page 7 line 241.
“In addition, compared with HD wallet, the proposed wallet which is created by material on chain project do not need to depend on private key to produce public, this design can effectively protect the security from the beginning.”
Point 4: In Section 2.3, Fig.5 illustrates the on-chain data process, however, the content of this paragraph is not clear enough, rewrite Fig.5 to make it more readable.
Response 4: Thank you for the comment. We now have rewritten this paragraph in page 8 line 261:
“Taking the coordination between manufacturer node and regulator node as an example:
Step 1: the manufacturer generates its own public key and private key through the key manager, encrypts the product information and calculates the fingerprint information.
Step 2: the regulatory department is responsible for registering the manufacturer's public key information, decrypting product information, and calculating fingerprint information.
Step 3: the transaction information is created by TX manager and verified with the manufacturer. After the verification is successful, the manufacturer merges the transaction information and fingerprint information through signature operation, signs the transaction information, and submits it to obtain TXID in the blockchain to complete the whole information on chain operation.”
Point 5: In Section 3.1, based on the data provided in Fig.7, it is concluded that the hash fingerprint form can reduce the transaction fee compared with the original form. With more numbers of characters, the more cost is observed by original form. What is the cost of the transaction fee when using more number of characters?
Response 5: Thank you for the comment. It is seen that if the number of on chain characters is 2000 characters, it is 3.1 times more expensive than 200 characters. However, the packing charges of the data which is hash fingerprint form is a constant 0.32 Dollar, resulting in a cheaper packing charges when the number of characters increases. To clarify the cost of the transaction fee when using more number of characters, the revised paper includes the following statement in page 10 line 317:
“When the number of characters become larger, the cost of this transaction fee will be more expansive.”
Point 6: In Section 3.3, it is seen that the traceability process of information is found in Ethereum browser as shown in Fig.10. The on-chain information can be traced by transaction hashes and a certain block height. We note that the history record is also stored in smart phones, does the smart phone also record the information via transaction hash and a certain block height?
Response 6: Thank you for the comment. The on-chain information is traced by transaction hashes and a certain block height, and the history record is not only found in Ethereum browser, but also stored in smart phones, the transaction hashes and block height do not need to store in smart phone, we could concisely find the history record in smart phone.
Point 7: The language should be polished by native speakers.
Response 7: We have polished the English writing carefully, including problems related to terminology、typographical errors、word inconsistent、tense etc.
Reviewer 2 Report
- Blockchain is implemented in the proposed scheme. But most importantly the background working principle of the Blockchain is totally missing from the article, especially consensus algorithms. That will pave the way for the feasibility of using Blockchain.
- Secondly, In the RELATED WORK section, the author are suggested to highlight papers related to blockchain (e.g., Ethereum, hyperledger and others)
More existing works on the blockchain are advised to be added. The follows instances are advised to be included but not limited to:
• https://0-doi-org.brum.beds.ac.uk/10.3390/electronics8050505
• https://0-doi-org.brum.beds.ac.uk/10.3390/s20082195
• https://0-doi-org.brum.beds.ac.uk/10.1109/ACCESS.2021.3049325
• https://0-doi-org.brum.beds.ac.uk/10.1109/ACCESS.2021.3060457
• https://0-doi-org.brum.beds.ac.uk/10.3390/s21051640
• https://0-doi-org.brum.beds.ac.uk/10.3390/s20123604
• https://0-doi-org.brum.beds.ac.uk/10.3390/s21041467
• https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10010041hould be a comparison of Blockchain complexity based on the consensus algorithms, i.e., power consumption, hardware resources, memory allocation, etc. This information is totally missing, making the use of Blockchain totally insignificant for the proposed scheme. - External cyber attacks and cyber risk assessment statements are missing from the article.
- Comparative performance analysis of your proposed scheme with the existing techniques should be given so that one can clearly see the impact of a new scheme in terms of percentage. Otherwise sometimes adding complexity to a power-constrained does not serve the purpose.
- The paper contribution section doesn't provide clear information related to the proposed system. I suggest making a separate contribution section and give more clear information related to this paper.
- The introduction contains a set of very good points/ideas but it is not well structured. I would recommend to the authors to include a Figure that will systemize and structure all these points while also better highlighting the challenges that this paper will address.
- Increase the related work section and give more information related to recently published papers.
- I suggest creating a separate subsection for each related topic.
- The author is advised to make a scenario diagram which depicts the proposed case study.
- Lastly, the authors should carefully proofread the manuscript and correct all grammar issues or misspellings
Author Response
Response to Reviewer 2 Comments
Point 1: Blockchain is implemented in the proposed scheme. But most importantly the background working principle of the Blockchain is totally missing from the article, especially consensus algorithms. That will pave the way for the feasibility of using Blockchain. Secondly, In the related work section, the authors are suggested to highlight papers related to blockchain (e.g., Ethereum, hyperledger and others) More existing works on the blockchain are advised to be added. The follows instances are advised to be included but not limited to:
https://0-doi-org.brum.beds.ac.uk/10.3390/electronics8050505
https://0-doi-org.brum.beds.ac.uk/10.3390/s20082195
https://0-doi-org.brum.beds.ac.uk/10.1109/ACCESS.2021.3049325
https://doi.org/10.1109/ACCESS.2021.3060457
https://0-doi-org.brum.beds.ac.uk/10.3390/s21051640
https://0-doi-org.brum.beds.ac.uk/10.3390/s20123604
https://0-doi-org.brum.beds.ac.uk/10.3390/s21041467
https://0-doi-org.brum.beds.ac.uk/10.3390/electronics10010041
This should be a comparison of Blockchain complexity based on the consensus algorithms, i.e., power consumption, hardware resources, memory allocation, etc. This information is totally missing, making the use of Blockchain totally insignificant for the proposed scheme. External cyber attacks and cyber risk assessment statements are missing from the article. Increase the related work section and give more information related to recently published papers. I suggest creating a separate subsection for each related topic.
Response 1: Thank you for the comment. Taking the advice, we add a literature review section in page 4 line 108 to better illustrate background working principle of the blockchain, including consensus algorithms, Ethereum, power consumption, cyber risk assessment and privacy mechanism, the details of revised paper are shown as following:
“2. Literature review
This section contains the details about the blockchain technology used in supply chain and some recent blockchain researches overview.
2.1. Blockchain working principle
Blockchain is known as a distributed ledger by using a lot of novel technologies which can be used to share digital data[24]. Blockchain is composed of a linked block sequence to store the transaction, which uses a public key password and verification of the network community to protect the time stamped transaction[25]. When the data is stored in a blockchain, the information cannot be modified, resulting in the non-tamperability of blockchain[26]. The long time application of blockchain requires less money, and can employ real information for companies and consumers, which could be traced from raw material to final product. Blockchain is a significant technology, since it can reduce the time of the transaction from days to instantaneously, save the costs, prevent the cyber crime, and increase security of the record. The details of blockchain technology are shown below:
(1) Consensus Mechanism: The consistency and integrity in blockchain is provided by consensus protocol, and the transactions are assured across the distributed nodes[27]. Pow is one of the typical existing consensus protocols, which is developed to realize bitcoin transactions, and nearly 47.1 teraWatt/hour energy will be consumed every year[28]. The disadvantage of this consensus mechanism is high energy consumption, which reduces the application of the system in many situations. Thus, new consensus protocols have been proposed to deal with this problem, for instance, Proof of Stake (PoS) and Practical Byzantine Fault Tolerance (PBFT)[29]. The energy consumption is reduced by some consensus protocols, while some of these consume more energy. In this paper, the information on chain operation is realized by using Ethereum, which is the most popular platform for smart contracts[30]. Two types of accounts are supported by Ethereum, user-controlled account and contract account, both of them can store the Ethereum currency ether[31]. The contract account must be activated by user-controlled account, and executing functions requires the user-controlled account to pay for gas using the ether currency. The price of gas can determine the conversion rate of gas to ether. The gas is similar to transaction fee to give miners reward to include transactions into blocks. The miner who successfully concludes the transactions is rewarded five ethers[32].
(2) Privacy Mechanism: The private key and public key encryption are important technology of the blockchain system, which have been used for information and data security[33]. The researchers now have found that blockchain technology is a very useful solution to the privacy demand through decentralizing data and information in many fields, such as IoT networks, supply chain, and medical networks[34]. Everyone can participate and the transactions in Bitcoin blockchain since it is publicly available. The private or public blockchain has to be related to the ledger and participation. Private blockchain determines who can participate, offering the power to one company or person which will hurt the trust between people[35]. The public blockchain may give better participation to the public. The advantage of private key and public key encryption technologies is that we could select the type of the blockchain to fit the need, so as to face the cyber risk problem of different communities[36].
2.2. Blockchain technology in supply chain
In the supply chain, blockchain can protect the visibility by capturing information from different nodes, including raw material, intermediate products, transportation to end product[37]. The overhead and agency costs of companies can be reduced, the tampering and fraud can be decreased through increasing trust using shared processes and records. Blockchain technology can effectively help the retailers recall specific suspected products rather than the entire product line[38].
The typical nodes in the supply chain is listed in Figure 1. In fact, there should be more nodes in the supply chain of wind turbine blades, the number of nodes could increase on the basis of the actual needs. Blockchain provides the following services to the supply chain:
(1) Non-tamperability. The supervising engineer shall carefully review the production qualification, equipment status, and other relevant information of blade manufacturers. Once the data is stored on the blockchain, it cannot be not tampered, which can prevent the enterprises from tampering or destroying the data adverse to them[39].
(2) Data transparency and privacy protection. Blockchain technology can not only realize the non-tamperability of data on the chain, but also protect the privacy of individuals that need to be hidden. It can also control the data that enterprises want to share, give the relevant quality supervision department higher viewing authority, and realize the acceleration of transaction speed and quality improvement on the supply chain[40].
(3) Traceability of quality problems. During the manufacturing process of blades, the supervising engineer shall carefully complete the inspection and upload the data at the preset quality witness place[41]. For example, some specific parameters should be recorded in the manufacturing process, such as temperature, time, and mechanical properties etc. Before transporting the blades, the supervising engineer shall review the transportation scheme, transportation mode and transportation conditions, etc. The important node information in many nodes of the supply chain can be stored on the chain, which can facilitate the query and trace the problems in the operation of turbine blades, so as to improve the quality of each node in the supply chain.
To the author’s knowledge, the green composite product system based on blockchain technology to monitor the quality problem in the supply chain, has been seldom found in the literatures. The conceptual framework provided in this paper can be an effective solution to the quality challenges of monitoring the important nodes in the green product supply chain and sharing the important data in this field.”
Point 2: Comparative performance analysis of your proposed scheme with the existing techniques should be given so that one can clearly see the impact of a new scheme in terms of percentage. Otherwise sometimes adding complexity to a power-constrained does not serve the purpose. The paper contribution section doesn't provide clear information related to the proposed system. I suggest making a separate contribution section and give more clear information related to this paper.
Response 2: Thank you for the comment. Taking the advice, we have added a new section “4.4 Comparative performance analysis” in page 13 line 373, this section gives the performance of the system and the details are given below:
“The performance of the proposed system is shown in Figure 12 and 13.
In Figure 12, the latency of on chain transaction of the system with three participants groups as average, minimum and maximum form is investigated. It is found that the average latency of 200 participants is 2728ms, when the number of participants increases to 400, the average latency is 2915ms. However, if the participants increase to 800, the average latency will reach 3262ms. In the case of the participates with 200, 400 and 800, the minimum latency is 1620ms, 1835ms and 2168ms, while the maximum latency is 3836ms, 3995ms and 4356ms, respectively. The tendency of the on-chain transaction is that the latency increases with the increasement of participants.
In Figure 13, we study the traceability transaction latency when participates search the history records in the blockchain network. The latency of traceability transaction of the system with three participants groups as average, minimum and maximum form is investigated. We found that the average latency of 200 participants is 264ms, when the number of participants increases to 400, the average latency is 284ms. If the participants increase to 800, the average latency will reach 299ms. In the case of the participates with 200, 400 and 800, the minimum latency is 78, 86ms and 90ms, while the maximum latency is 450ms, 482ms and 506ms, respectively. From Figure 13, it is observed that the traceability transaction latency can be neglected with the increasement of participants.”
We also add some discussions about the comparison between proposed system and systems in references [42] and [43], and the results are shown in Table 3:
“The quality control system described in this paper is compared with other methods. Table 3 gives the results of this comparison. The detail analysis is shown below:
(1) Traceability: the system proposed in this paper is a good example for traceability system, and the details are shown in the section 4.3. However, the system in reference [42] cannot reach this function.
(2) Regular role: the proposed system is based on blockchain, the regulator node and other nodes all participate in the system, they can easily join the system. As an early stage of blockchain application, regulator role will be very confused, since decentralization is one of the most important advantage of blockchain technology, while regulators are also significant power to make the supply chain more flexible and efficient. Thus, blockchain based system in this paper can make the regulator node more useful. In comparison with other methods, [43] has developed a system for the supply chain, but the regulator role in it is still very narrow.
(3) Scalability: the proposed system in wind turbine supply chain can further extend more methods and smart contracts to make quality control of the whole supply chain better.”
Point 3: The introduction contains a set of very good points/ideas but it is not well structured. I would recommend to the authors to include a Figure that will systemize and structure all these points while also better highlighting the challenges that this paper will address.
Response 3: Thank you for the comment. We have added a figure 2 in page 1 line 77 to better conclude the main problem existing in present supply chain, and the challenge in this field is also given to highlight the problem in supply chain, so as to make the problems solved by blockchain more clearly.
Point 4: Lastly, the authors should carefully proofread the manuscript and correct all grammar issues or misspellings
Response 4: Thank you for the comment. We have checked the English writing carefully.
Round 2
Reviewer 2 Report
Thank you for addressing the comments however this manuscript still requires the following changes.
The author should clearly conduct the critical analysis to determine the linkage or the need of the proposed work in the context of the contemporary state of the art.
What is the novelty of issues being addressed in the proposed study that has been overlooked by the existing model?
Authors should also compare their results with existing models in terms of block size, the number of peers, throughput, latency, and consensus algorithm.
Author Response
Response to Reviewer 2 Comments Round2
Point 1: The author should clearly conduct the critical analysis to determine the linkage or the need of the proposed work in the context of the contemporary state of the art.
Response 1: Thank you for the comment. Taking the advice, we add a Table 1, which is “Critical analysis of the blockchain technology used in supply chain” to introduce the latest researches of this issue. We found that the regulators role, reducing the transactions fee of Ethereum and green composite wind turbine blade supply chain system based on blockchain are limited in the literatures, and these points are focused in this paper, we explain this revision in page 6 line 195, and the details are shown below:
“To the author’s knowledge, the green composite product system based on blockchain technology to monitor the quality problem in the supply chain, the regulators role, reducing the transactions fee method of Ethereum have been seldom found in the literatures. The conceptual framework provided in this paper can be an effective solution to the quality challenges of monitoring the important nodes in the green product supply chain and sharing the important data in this field.”
Point 2: What is the novelty of issues being addressed in the proposed study that has been overlooked by the existing model?
Response 2: Thank you for the comment. The novelty of this paper is that the regulators role issue, reducing the transactions fee of Ethereum and green composite wind turbine blade supply chain system based on blockchain are limited in the literatures, we have added a contribution part in introduction in page 3 line 103 to better illustrated the novelty of this paper, the details are given below:
“The main contribution of this paper is given as below：
- The main aim of this paper is to develop the quality control system of green composite wind turbine blade supply chain, since few efforts have been done to establish this system.
- The proposed system can realize the traceability of the green composite wind turbine blade supply chain, and the data on chain method and trace process are illustrated in the paper. The quality of the product could not only be examined and verified by regulator, but also be monitored by other related nodes.
- We develop a new way to store the data by hash fingerprint and the cost of transaction fee of Ethereum is significantly reduced in the case of a large amount of data.
- The existing supply chain system has not improved the role of the regulators, thus, the sharing and monitoring roles of the regulators are discussed in proposed system.
”
Point 3: Authors should also compare their results with existing models in terms of block size, the number of peers, throughput, latency, and consensus algorithm.
Response 3: Thank you for the comment. The block size, the number of peers, throughput, latency and consensus algorithm are indeed important issues for blockchain based systems, and the comparisons with the existing model are necessary for the application in practice. However, the most important novelty of this paper is the regulators role issue, reducing the transactions fee of Ethereum method and blockchain based green composite wind turbine blade supply chain system (as explained in the response to point 1). Thus, we have also extended Table 4, and more details comparisons about traceability, regulators role,
In addition, considering that the comparisons of the block size, the number of peers, throughput, latency and consensus algorithm are definitely a potential research direction, to clarify this, the revised paper added the following statements in page 15 line 456 in the conclusions section:
“To improve the applicability, it is worth testing the proposed blockchain-based systems in future research from various aspects, such as the block size, the number of peers, throughput, latency, consensus algorithm and wallet structure.”
Author Response File: 
Author Response.docx
Round 3
Reviewer 2 Report
Thank you for addressing the comments. Now, this manuscript is ready for publication. Good Luck.
