Sub-Trajectory Segmentation for Mobility Data Anonymization
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing location-based services face a challenge in maximizing data utility while minimizing privacy risks, as privacy-enhancing algorithms often reduce the accuracy of mobility data, and existing anonymization techniques may not effectively protect against background knowledge attacks.
Innovation Solution
Generate sub-trajectories based on changing points, introducing gaps at these points to anonymize mobility data, ensuring that potential attackers cannot gain additional information beyond their background knowledge, using a method that iteratively selects observation points, calculates visible points, and identifies changing points to split trajectories into sub-trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If privacy-enhancing algorithms are applied to mobility data, then user privacy is protected, but data accuracy is reduced
Solution Approach 1:
The patent segments the complete trajectory into multiple sub-trajectories by identifying changing points where the visibility context changes. Each sub-trajectory is processed independently with gap introduction, allowing privacy protection to be applied locally without compromising the overall data utility. This segmentation enables selective anonymization at critical points while preserving accurate movement patterns in other segments.
2Object-affected harmful factors
If traditional anonymization techniques are used, then privacy protection is provided, but effectiveness against background knowledge attacks is insufficient
Solution Approach 1:
The patent performs preliminary identification of changing points where visibility context changes before applying anonymization. By pre-calculating which segments require gap introduction based on visibility analysis, the system proactively prevents background knowledge attacks rather than reacting to them. This preliminary action ensures that sensitive information is protected before any attack scenario can be exploited.
Solution Approach 2:
The patent dynamically adjusts anonymization parameters such as gap length and sub-trajectory boundaries based on the specific visibility context and changing points identified in the data. Rather than applying fixed anonymization rules, the system adapts the degree and location of anonymization to match the actual privacy risks present in different trajectory segments, improving effectiveness against targeted attacks.
3Productivity
If complete trajectory data is published, then data utility is maximized, but privacy leakage risk increases
Solution Approach 1:
The patent applies different quality levels of anonymization to different parts of the trajectory based on local privacy risks. At changing points where visibility context changes, stronger anonymization with gap introduction is applied, while other segments maintain higher data quality. This local differentiation preserves data utility in low-risk areas while providing enhanced protection where needed, achieving a balanced solution rather than uniform anonymization.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An apparatus and a method for generating sub-trajectories for a trajectory are disclosed. The method includes retrieving trajectory data comprising a plurality of data points defining a trajectory and iteratively executing a set of operations until a termination condition is met. The set of operations include selecting an observation point associated with the plurality of data points and calculating a set of visible points comprising one or more data points from the plurality of data points associated with the observation point based on a predefined visibility context criterion. The method further includes identifying a changing point from the plurality of data points based on the iterative execution of the set of operations, and generating a sub-trajectory for the trajectory such that the changing point indicates a starting point of the sub-trajectory.