Research On Spatio-temporal Data Storage And Query Method Based On Improved Block-DAG Blockchain

In recent years,with the rapid development of Internet technology,a large number of spatiotemporal data will be generated at any time in the network.Spatiotemporal data are data types with time dimension,spatial dimension and other attributes at the same time.Spatiotemporal data is widely used in supply chain,e-commerce,logistics and other fields.Therefore,in practice,it is of great significance to ensure the safe storage and fast query of spatio-temporal data.At present,the main storage methods of spatiotemporal data are centralized storage and distributed storage,but there are still problems such as data opacity and easy to be tampered with.At the same time,it is easy to form data islands and can not share data effectively.Ensuring the safe storage and efficient query of spatiotemporal data has become a hot issue in the field of spatiotemporal data research.Blockchain technology has the characteristics of decentralization,tamper proof and traceability,which meets the management requirements of spatiotemporal data.Therefore,it is considered to combine spatiotemporal data management with blockchain technology and use the characteristics of blockchain technology to realize the safe storage and efficient query of spatiotemporal data.However,the existing blockchain technology has limited support for spatiotemporal data management.Firstly,the traditional blockchain technology is difficult to meet the high throughput requirements of spatiotemporal data;Secondly,the cumbersome voting confirmation mechanism leads to long confirmation time of spatiotemporal data and slow speed of chain up;Finally,the traditional blockchain technology has limited support for data query,which is difficult to meet the query requirements of spatio-temporal data.Aiming at the problem that the traditional blockchain technology has low support for spatio-temporal data management,combined with the Directed Acyclic Graph blockchain(Block-DAG),this paper proposes a blockchain construction and query method of surface spatio-temporal data.The main research contents and innovations of this paper are as follows:(1)Firstly,to address the problems of current spatio-temporal data management methods and the limited support of traditional blockchain technologies represented by Bitcoin and Ethereum for spatio-temporal data management,this paper proposes an improved Block-DAG-based spatio-temporal data blockchain architecture ST?BlockDAG(Spatio-Temporal Block-DAG).To improve the efficiency of inter-node routing in the ST?Block-DAG blockchain network,a structured P2 P communication mechanism,NC-chord(Node Clustering chord),is proposed based on node classes and communication requirements.(2)Secondly,to address the problem of inefficient query of the storage structure inside the traditional blockchain,a storage structure F-L Tree(Four-Link Tree)based on quadtree and single-linked table is proposed inside the ST?Block-DAG blockchain by combining the temporal and spatial dimensions of spatio-temporal data.First,the spatio-temporal data in the dataset is divided according to the median of spatiotemporal attributes,and the root node is divided into four sub-nodes;second,the subnodes are divided in the same way until the spatio-temporal data in each sub-node is less than the threshold k.Finally,the F-L Tree is constructed in a bottom-up manner.(3)Then,in order to improve the query efficiency of spatio-temporal data,various types of spatio-temporal data query methods are proposed in ST?Block-DAG based on quadtree and single-linked table storage structure,including single-value query and range query of spatio-temporal data.When performing spatio-temporal data query,all blocks that meet the query conditions are firstly identified based on the block header information,and then the F-L Tree within the blocks that meet the query requirements are retrieved sequentially to obtain the data that meet the query conditions and get the query results.(4)Finally,it is experimentally verified that the proposed spatio-temporal data blockchain architecture ST?Block-DAG effectively improves the support for spatiotemporal data compared with the traditional blockchain in terms of enhancing data throughput and improving the query efficiency of spatio-temporal data.