2.19 The ‘Client’ node.
Figure 2.20 The ‘MainContractor’ node.
Figure 2.21 The ‘SubContractor’ node.
Now, the node of the main contractor will execute the following command to initiate the flow in which a task is created and assigned, as in Figure 2.22: flow start CATInitiatorFlow Client: Client, sub-Contractor: SubContractor, taskID: 01, taskDesc: “Bricks should be laid out”, amount: 100, assignee: “SubContractor”, deadline: “2020-10-23T10:12:35Z”.
Figure 2.22 The output on the MainContractor’s node.
This command will return a transaction id/hash after verifying the collected signatures and broadcasting this transaction to other participants which results in the completion of the flow. To check whether this transaction has been broadcasted, we need to see the vaults of the three nodes. Therefore executing run vaultQuery contractStateType: com.Task.states.TaskState in every node once again returns the same output in all the three nodes, as in Figure 2.23.
Figure 2.23 The output on all the nodes.
This output shows all the information regarding the transaction that has been carried out. There are two sections of the output here:
states—this section shows the data and values stored in the parameters mentioned in Figure 2.1. It also contains information about the contract, notary, constraint, key, etc., and the transaction hash and index by which this transaction can be referenced.
statesMetadata—this section shows the information about the transaction hash, index, recorded time, consumed time, status, notary, etc.
The transaction hash from both the sections of this output is similar to the transaction hash in the output represented in Figure 2.22. Whenever new transactions will be carried out, they will be appended to this transaction in the respective vaults and the timestamp will be recorded. Hence, nobody can tamper with the information stored in the vaults and every participant in the transaction is answerable in case of any mishap as the transactions contain their digital signatures. The advantage of using Corda in this scenario is that if there were more participants in this network, this transaction would only be stored in the vaults of the participants who were involved in the transaction that took place. Therefore, all the participants will act responsibly and the client will have information about the expenditure at every step and cannot be deceived by anyone.
2.5 Future Work
Although this chapter has concentrated on the relation between the client, the main contractor, and the subcontractor, there are many possibilities of expanding the usage of blockchain technology as well as distributed ledger technology in the construction industry to optimize the traditional procedures that are followed to date. Firstly, a platform to serve as a reputation ledger for the main contractors and the subcontractors can be developed. This platform can provide a detailed statistical analysis of the information associated to the total number of contracts taken, the number of contracts completed successfully, the number of contracts that were failed to complete, the number of pending contracts, probability of finishing the contract within the given deadline, the average fee charged for contracts, the capability of cost-effective production and management, rapport maintained with co-workers, comments by previous clients, and many more. Overall, this platform would create a perfect user profile with trusted documentation of identities and an appropriate display of their technical skills. When all of this information related to the main contractors and the subcontractors is stored in a blockchain and is made available to the public, the clients will have no difficulty in choosing a contractor who is suitable for their task based on the clients’ affordability.
Secondly, a platform that acts as an umbrella for this ecosystem’s participants like a client, main contractor, subcontractor, bank, designers, consultants, insurance brokers, and authorities can be developed. This platform can eliminate a major percentage of the chapterwork and verification involved before any approval by the organizations like the bank or the government. In this way, all the permissions, approvals, etc. are digitalized, hence there is no chance of committing any fraud and all of this information remains secure due to the feature of immutability.
It is known that the construction industry is one of the world’s greatest consumer of raw materials. Hence, a platform for keeping track of the construction materials required in the complex supply chain can be developed. This platform can help in maintaining supply chain transparency and providing traceability of construction materials like sand, gravel, clinker, plaster, bricks, wood, etc. throughout the logistics chain. This will help keep the concerned participants in the loop regarding the status of the items that were procured. The aforementioned platform can be built with a combination of blockchain as well as Radio Frequency Identification (RFID) [60], therefore helping in avoiding the chances of any errors in the data due to human negligence or genuinely entered false information.
This industry involves the biggest and the most expensive projects in the world but the delayed payments torment the participants in the industry. Therefore, a platform with a tokenized system can be introduced into this industry. In other words, all forms of payment in the system will occur via tokens instead of cash, speeding up the project progress, and improving the security of the payments with the help of automated payments carried out through the smart contracts. All in all, this platform assures an increase in the speed, efficiency, and the certainty of payments.
Apart from using blockchain and distributed ledger technologies, other technologies like artificial intelligence and machine learning can also be utilized in this industry. With further advancements in the technologies, these processes can be further simplified in the future.
2.6 Conclusion
The construction industry is like the bedrock foundation of a global economy and this may be true owing to the ever-growing mass urbanization, indirectly leading to problems related to material, machine, man, and money. Therefore, this chapter has presented a detailed review of the major problems faced in this industry and introduced a solution using the distributed ledger technology. There have been many proposed solutions that use blockchain technology to overcome the problems faced in this industry. Instead, we propose a solution that uses Corda, a platform that runs on the distributed ledger technology, instead of a traditional blockchain.
In the case of the construction industry, there are many
