Ontology Pattern of Trajectory Anonymity for Query Events

Focused on the issue that most of existing anonymization scheme for trajectory cannot prevent attacks by background knowledge of queries, a novel ontology pattern of trajectory anonymity for query events was proposed that using the advantage of event ontology. Firstly, the data of identity privacy, geography information and sensitive query events was formulated by OWL, and a trajectory anonymity query pattern based on event ontology was established. Then all the query events in ontology were clustered into anonymized sets according to structural similarity and Jena reasoning engine, an inference service of query events for trajectory data was presented. Finally, the experimental results show that, our pattern can decrease the information loss by 5% to 15% in anonymity, while the query precision maintain on 65%. The proposed method can maintain the availability of trajectory during anonymity that triggered by ontology pattern.