Crowdsourcing Process Design And Consensus Algorithm Analysis For Blockchain Internet Of Things

With the explosive growth of connected smart devices and sensors,intelligent collaboration technologies have been widely used,and modern society has entered the era of the Internet of Things(Io Ts)from the Internet era.As a promising application of the Io Ts technology,crowdsourcing has attracted more and more attention,it uses widely distributed smart devices to sense,collect and analyze data,jointly completes many complex and tedious tasks,it is essentially a distributed problem-solving production model.However,crowdsourcing system faces many technical challenges in their practical operation,such as data security,personal privacy,and incentive provision.The emergence of blockchain technology effectively solves the problem of trust among individuals and provides new ideas for the design of decentralied systems.Therefore,this thesis designs a blockchain-based crowdsourcing system,and analyze the performance of a direct acyclic graph(DAG)consensus algorithm for the Internet of Things,to integrate the development of the Io Ts and blockchain technology.Firstly,the thesis introduces the background knowledge of the blockchain and elaborates its technical principles in detail.Then,the thesis analyzes and summarizes the current security,privacy,and incentive challenges faced by crowdsourcing based on the development of Internet of Things applications.In response to the above problems,a new blockchain-based crowdsourcing system is proposed.Using the reputation mechanism to enable users to complete tasks with high quality,and the business logic of crowdsourcing is realized by using smart contracts.The transparency and traceability of data processing are verified by deploying the crowdsourcing voting smart contracts.Finally,the Markov chain model is used to analyze the reliability of the blockchain-based crowdsourcing system.Then,aiming at the problems of energy consumption,time delay and monopoly existing in the consensus algorithm of proof-of-work(Po W)and proof-of-stake(Po S)mainly used in current blockchain network,the thesis takes the most representative Tangle network as an example to analyze and study the performance of DAG consensus algorithm for the Internet of Things.Specifically,Markov chain model has been adopted to illustrate the impact of dynamics of network load in the consensus process for DAG based blockchain networks.The analysis focuses on the performance of the Tangle network under the unstable network load mechanism caused by the fluctuation of the transaction arrival rate,including the cumulative weight of the transaction and the conformation delay.Simulation experiments show that the blockchain-based crowdsourcing system proposed in this thesis has the feasibility of implementation and can effectively improve the reliability of the system,and can provide theoretical guidance and solutions for the blockchain direction for Io T.The proposed analysis model of the DAG consensus algorithm can reflect the impact of the network load on the performance of the Tangle,it can not only explain the advantages and disadvantages of the DAG consensus algorithm,but also provide a reference value for the deployment of the blockchain Internet of Things.