Document Type



Doctor of Philosophy (PhD)


Computer Science

First Advisor's Name

Niki Pissinou

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

S.S. Iyengar

Second Advisor's Committee Title

Co-Committee Chair

Third Advisor's Name

Deng Pan

Third Advisor's Committee Title

Committee Member

Fourth Advisor's Name

Bogdan Carbunar

Fourth Advisor's Committee Title

Committee Member

Fifth Advisor's Name

Kang Yen

Fifth Advisor's Committee Title

Committee Member


User Privacy, Location-based Services, Probabilistic Inference, Search Query, Optimization, Mobile Sensing

Date of Defense



The mobile and wireless community has brought a significant growth of location-aware devices including smart phones, connected vehicles and IoT devices. The combination of location-aware sensing, data processing and wireless communication in these devices leads to the rapid development of mobile and location-aware applications. Meanwhile, user privacy is becoming an indispensable concern. These mobile and location-aware applications, which collect data from mobile sensors carried by users or vehicles, return valuable data collection services (e.g., health condition monitoring, traffic monitoring, and natural disaster forecasting) in real time. The sequential spatial-temporal data queries sent by users provide their location trajectory information. The location trajectory information not only contains users’ movement patterns, but also reveals sensitive attributes such as users’ personal habits, preferences, as well as home and work addresses. By exploring this type of information, the attackers can extract and sell user profile data, decrease subscribed data services, and even jeopardize personal safety.

This research spans from the realization that user privacy is lost along with the popular usage of emerging location-aware applications. The outcome seeks to relive user location and trajectory privacy problems. First, we develop a pseudonym-based anonymity zone generation scheme against a strong adversary model in continuous location-based services. Based on a geometric transformation algorithm, this scheme generates distributed anonymity zones with personalized privacy parameters to conceal users’ real location trajectories. Second, based on the historical query data analysis, we introduce a query-feature-based probabilistic inference attack, and propose query-aware randomized algorithms to preserve user privacy by distorting the probabilistic inference conducted by attackers. Finally, we develop a privacy-aware mobile sensing mechanism to help vehicular users reduce the number of queries to be sent to the adversarial servers. In this mechanism, mobile vehicular users can selectively query nearby nodes in a peer-to-peer way for privacy protection in vehicular networks.






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