Research On Trajectory Data Compression And Privacy Preserving Technology

With the development of localization technology and the popularity of intelligent mobile terminals,a large number of trajectory data have emerged,the trajectory data contains abundant spatiotemporal information and semantic information.The effective storage and management of trajectory data is of great significance to urban construction and people's daily life.This paper focuses on two outstanding problems in storage and management of trajectory data-trajectory data compression problem and privacy protection in trajectory data publishing,the main contributions are as follows:In view of the contradiction between the online trajectory data compression ratio and compression error,this paper proposes the online trajectory data compression algorithm based on relative SED filtering and online trajectory data compression algorithm based on dynamic SED calculation.The former is based on the compression ratio expected by users and stores trajectory points in turn generated,using the idea of TD-TR off-line trajectory data compression algorithm to remove the trajectory point with small error caused by the deletion from the current stored trajectory points when the compression ratio is larger than expected by the user.The latter is based on the user's given error distance threshold,the error in the calculation of trajectory points for deleted and may cause not only contains the error caused by itself and contains deleted effects on other non critical track points.On this basis,some of the critical track points are selected from the track for storage.The performance of the proposed trajectory data compression algorithm is tested by experiments on real trajectory datasets and the experimental results show that the proposed trajectory data compression algorithm can effectively alleviate the contradiction between compression ratio and compression error in trajectory data compression.In view of the problem of privacy protection problem in trajectory data publishing,this paper proposes a privacy protection algorithm based on multi trajectory characteristics.The proposed algorithm combines the uncertainty of trajectory data.Firstly,the similarity between trajectories is measured by the differences of the trajectories in the aspects of direction,speed,time and space,and then trajectory clustering is carried out.And then the k-anonymity of the trajectory is realized by spatial translation,as far as possible to meet the privacy protection needs of the premise to improve the availability of anonymous trajectory data.Finally,through experimental verification of the proposed privacy protection algorithm and the classical algorithm in the field of privacy protection to meet privacy requirements under the premise of the same can make the trajectory data of the whole data is anonymous higher availability.To sum up,the researches on trajectory data compression and privacy protection algorithm can solve the contradiction between compression ratio and compression error in trajectory data storage problem and anonymous data availability issues in trajectory data privacy protection publishing and that has important practical significance on the application of trajectory data.