| With the proliferation of short-range wireless communication technologies(such as D-SRC),the passing vehicles and Road Side Units(RSUs)can exchange their information,thus forming a vehicular cyber-physical system(VCPS).A key benefit of vehicular cyber-physical systems is automatic traffic volume estimation.However,the location and trajectory privacy of vehicles may be leaked from the recorded traffic data.Then,how to accurately estimate the traffic volume while protecting the location and trajectory privacy of vehicles has become one of the important topics in the fields of transportation engineering and ve-hicular cyber-physical system.We study the problem of privacy-preserving transportation traffic volume estimation,and the main work and innovations of this thesis are as follows:(1)We propose a random encoding mechanism based on differential privacy(2)We solve the problem of point-to-point traffic volume estimation based on differen-tial privacy.Based on the proposed random encoding mechanism,we propose a new point-to-point traffic volume estimator.Then,through rigorous mathematical analysis,we prove that the proposed random encoding mechanism satisfies ∈-differential privacy for protecting the location and trajectory privacy of point vehicles and point-to-point common vehicles.Finally,based on real traffic traces data,we perform simulations to verify the effectiveness of the proposed point-to-point traffic volume estimation method.(3)We solve the problem of multi-point traffic volume estimation based on differential privacy.To address the issue that the existing estimator is too complicated and has low practicality,we propose a new multi-point traffic volume estimator.Then,through rigorous mathematical analysis,we prove that the proposed random encoding mechanism satisfies ∈-differential privacy for protecting the location and trajectory privacy of multi-point common vehicles.Finally,based on real traffic traces data,we perform simulations to verify the effectiveness of the proposed multi-point traffic volume estimation method(4)We solve the problem of persistent traffic volume estimation based on differential privacy.To address the problem of insufficient consideration of the related persistent com-mon vehicles in the existing estimators,we propose new estimators for persistent point,persistent point-to-point and persistent multi-point traffic volumes.Then,through rigorous mathematical analysis,we prove that the proposed random encoding mechanism satisfies∈-differential privacy for protecting the location and trajectory privacy of persistent com-mon vehicles.Finally,based on real traffic traces data,we perform simulations to verify the effectiveness of the proposed persistent traffic volume estimation method. |
