Privacy preservation has recently received considerable attention for location-based mobile services. Various location cloaking approaches have been proposed to protect the location privacy of mobile users. However, existing cloaking approaches are ill-suited for continuous queries. In view of the privacy disclosure and poor QoS (Quality of Service) under continuous query anonymization, in this paper, we propose a Δ  p  -privacy model and a Δ  q  -distortion model to balance the tradeoff between user privacy and QoS. Furthermore, two incremental utility-based cloaking algorithms ---  bottom-up cloaking  and  hybrid cloaking , are proposed to anonymize continuous queries. Experimental results validate the efficiency and effectiveness of the proposed algorithms.
['Xiao Pan', 'Xiaofeng Meng', 'Jianliang Xu']
Distortion-based anonymity for continuous queries in location-based mobile services