Research On Keyword Query Method Of Uncertain RDF Graph

With the development of the Semantic Web,RDF has become a widely used standard data model for the Semantic Web.However,due to the inherent errors and noises that cannot be eliminated in existing data acquisition techniques,uncertain RDF data widely exists.Uncertain RDF graph is a structured knowledge base based on graph structure,which can effectively organize scattered knowledge and facilitate users to quickly find the required information.In recent years,the query of uncertain RDF graph data has gradually become a research hotspot,and the keyword query method,as one of the most basic query methods in the field of data query,allows ordinary users not to be familiar with any language or underlying data structure,and can also conveniently to retrieve information from the knowledge base.Based on the current research,this paper designs and implements a query algorithm for uncertain RDF keywords.The main work of the thesis is as follows:(1)Extension of uncertain RDF data model.The traditional RDF triple model is not ideal for representing and processing uncertain data,and it can be reasonably modeled as a graph model for keyword query.This thesis expands on the traditional RDF data model,introduces probability tuples according to uncertainty theory,uses this model to represent the relationship between entities in the real world and the degree of relevance of facts,and defines keyword queries on uncertain RDF graphs.(2)Design of uncertain RDF keyword query algorithm.My algorithm consists of three modules:preprocessing,query pruning,and top-k sorting.In the preprocessing phase,the information in the data graph is stored in a double-indexed structure to lay the foundation for the query module.In the query phase,techniques such as traversal,structural pruning,and probability pruning are used to reduce the number of irrelevant nodes in the query results to improve query speed and reduce data noise.To ensure query accuracy,a scoring function is designed to sort the candidate set’s structure and content and return the top-k result set.(3)Develop an uncertain RDF keyword query system,and design experiments to verify the query performance of the algorithm.Design experiments Through different scales of experimental data,different groups of query keywords,and different parameters and benchmark algorithms,multiple groups of comparative experiments were conducted to evaluate the query method.The experimental results show that the algorithm is better than the benchmark algorithm in terms of query response time and query accuracy.performance has been improved.At the same time,a system for querying uncertain RDF keywords is built.Finally,it summarizes and analyzes,and conducts research and discussion on the future work direction and work difficulties.