# A Serious Gaming Approach for Crowdsensing in Urban Water Infrastructure with Blockchain Support
## 2 Related Work
### Blockchain for Water Resource Management  
According to [PERSON], [PERSON] and [PERSON] [83], several algorithms for consensus can be used depending on the blockchain type: Proof of Work, Proof of Stake, Delegate Proof of Stake, Proof of Existence, Proof of Activity, Proof of Elapsed Time and Byzantine Fault Tolerance. One of the first used consensus algorithms is Proof of Work. Originally used in Bitcoin, Proof of Work continues to ensure very high security but with a high energy cost. [PERSON], [PERSON], and [PERSON] [84] performed a survey about consensus algorithms used in blockchain applications and presented the following technologies: Hyperledger Fabric, Corda and Stellar Consensus Protocol. With the help of intelligent sensors, a large number of data can be collected. For integrating these modern technologies [85] to provide an increased level of trust, smart contracts can be used, which are based on secure and immutable data. This helps the validation process in an efficient way and supports decision making [86]. [PERSON] et al. [87] propose such a water control system, based on blockchain networks, where community members have the opportunity to establish rules regarding the use of water quotas. These rules are implemented through a smart contract [45]. The main challenge is to transform water control techniques into a distributed system that all members of the community can trust. Given that in recent years, natural phenomena such as floods, droughts, tsunamis and hurricanes have increased significantly, government organizations have considered the development of smart, sustainable and safe infrastructure to monitor water consumption [88,89]. A particularly important problem is found in rural as well as urban areas and consists in ensuring the necessary quality and quantity of water [90]. This approach has been successfully implemented in Australia and Singapore [91, 92, 93]. In Australia, the South East Queensland (SEQ) water network was established for the ultimate purpose of managing and securing urban water supply [94]. The water supply network established in Singapore is based on water collection, management, recycling and distribution [94,95]. Intelligent sensors were used for real-time monitoring of water quality, as well as analytical tools to support decision-making systems, while the developed system ensured a sustainable and efficient management of the water supply network using blockchain technology [90]. In 2017, start-up Civic Ledger [96] realized a feasibility study related to the transparency of Australian water markets, with the aim of increasing the trust, transparency and reliability of water trading. During the feasibility study, Civic Ledger developed a peer-to-peer trading platform that provided irrigators with secure and transparent trading. Another approach is presented by [PERSON] et al. [97] aiming to streamline energy costs through good management of water resources, integrating IoT sensors and blockchain. The architecture includes IoT devices, a public blockchain and smart contracts representing the interests of different stakeholders in water management. Moreover, smart contracts have the role of regulating the distribution of incentives among farmers. [PERSON] et al. [98] use the blockchain platform for trading, thus reducing energy costs. Another approach presented by [PERSON] and [PERSON] [99] proposes a solution based on gamification, through which data are taken from IoT devices, which come from the utility company. Furthermore, data are used in the gamification process, and blockchain plays an essential role in preventing dishonest behavior. A recent study detailed in [87] presents an intelligent system through which irrigation communities can communicate and manage water resources. Community members use blockchain to increase confidence in the data collected from IoT devices.