A Research And Implementation On Heterogeneous Data Integration Middleware Based On RDF

With the continuous development of the Internet of Things industry,distributed services are gradually increasing,and the databases used by each subsystem and the data types stored are slightly different.These data from different sources and formats cause the Io T system to fail to operate normally.Therefore,the processing of heterogeneous data has become the primary task.Based on this background,this thesis proposes a solution of heterogeneous data integration middleware based on RDF(Resource Description Framework),which aims to solve the problem of "information island" caused by heterogeneous data and improve the reliability of the Internet of Things system.operation efficiency.The main work of this thesis is as follows:A research scheme of RDF-based heterogeneous data integration middleware is proposed,which is divided into five layers from top to bottom: application layer,data query layer,semantic layer,data encapsulation layer,and data layer.Design each level interface,realize the level connection,and complete the system function.First,the data query processing module is designed in the data query layer.Introduce SPARQL(SPARQL Protocol and RDF Query Language,RDF Query Language)query technology and improved Cost-Based Optimization algorithm.The cache function is designed to cache hot data to improve query efficiency.Secondly,the semantic module is designed in the semantic layer,and semantic technology is introduced to establish the corresponding local ontology for the underlying heterogeneous data sources.The global ontology is constructed after extracting the same concepts from each data source;the ontology mapping algorithm is integrated into the semantic layer to realize the one-to-one mapping between the local ontology and the global ontology.Finally,the data encapsulation module is designed in the data encapsulation layer to realize the function of query transformation and result transformation.In this study,an RDF-based heterogeneous data integration query platform test system was developed.Experiments are carried out on the data query layer,the semantic layer,and the data encapsulation layer respectively,and the results show that the functions of the three layers are feasible.Design experiments to compare this research with existing data integration and query schemes.First,an experimental comparison of query efficiency is carried out.The experimental results show that the query efficiency of the proposed scheme is better than the existing scheme,and the efficiency is improved by 1.3-10 times.Secondly,compare the accuracy rate experiments.The experimental results show that the query accuracy rate of the proposed scheme is 60%～63%,and the floating rate is 0～3.2%,indicating that the stability of this research is better than the existing scheme.From this,it is concluded that the RDF-based heterogeneous data integration and query scheme designed in this thesis is feasible,the developed data query platform has good efficiency,and effectively improves the data query efficiency of heterogeneous system interoperability.