Skyline Query Based On Differential Privacy In Road Network Environment

With the continuous development of today’s big data era,spatial database queries are receiving more and more attention from researchers,and Skyline query techniques are highly favoured in spatial queries.Due to the diversity of data,protecting the privacy of data has also become hotspots for researchers to study in recent years,and differential privacy techniques have also received much attention as one of the many methods to protect privacy.In the road network environment,researchers have partially investigated the spatial Skyline query method,but the query for privacy protection of data is still inadequate.In order to further meet the query needs of practical situations,this paper focuses on solving the problem of differential privacy-based spatial Skyline queries in the road network environment.Firstly,this paper studies the problem of differential privacy-based Skyline query in the road network environment and proposes a differential privacy-based Skyline query algorithm in the road network environment,which consists of four parts.The first part is the data pre-processing phase,which uses the hierarchical Skyline derived from the Skyline dominance relationship to filter some of the useless data points and obtain the candidate sets.The second part is the data pruning phase,where the data set is refined using the Voronoi graph index structure,improving efficiency for subsequent operations.The third part further refines the data according to the proposed pruning algorithm of the extended tree of the grid index,and proposes a Skyline query algorithm for the road network environment to improve the query efficiency.The fourth part proposes a differential privacy budget allocation publishing algorithm based on information dispersion,and adds corresponding noise to the privacy budget parameters assigned according to the privacy budget allocation model to better protect the privacy of the data,in view of the existing road network Skyline query without considering the data privacy problem.The Skyline query problem based on time-varying information in the road network environment is further investigated,and the Skyline query algorithm based on timevarying information in the road network environment is proposed.The algorithm is divided into three parts,the first part is to deal with the changes in the result set arising from the changes in the time-varying attributes of the objects,and the pruning algorithm based on time-varying attributes is proposed to update the result set.The second part deals with the time-varying information of the road network,and the result set is updated accordingly through the proposed data structure for storing node information and pruning rules.The third part performs a Skyline query on the pruned data and proposes a Skyline update algorithm to obtain the final query result set.