Trajectory Anonymization via Sub-Trajectory Segmentation

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Solution Overview

Problem

Existing location-based services face challenges in maintaining user privacy while maximizing data utility, as current anonymization methods often discard high-value data points, leading to lower quality services and customer dissatisfaction.

Innovation Solution

A method that segments trajectories and introduces gaps based on tailored use cases to retain data points with higher utility, using a processor to identify and establish sub-trajectories and gaps that satisfy specific temporal length ranges, ensuring anonymity and utility retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If trajectory data is anonymized by discarding data points, then user privacy is protected, but data utility and service quality deteriorate

Engineering Contradiction:
Improveuser privacy protectionVSAvoiddata utility
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent segments the trajectory into multiple sub-trajectories by identifying high-value data points and creating gaps around them. This segmentation allows the system to protect privacy through anonymization while preserving the utility of high-value data points by isolating them in separate sub-trajectories that can be selectively retained or processed.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies different treatment to different parts of the trajectory based on their value. High-value data points receive special protection through gap creation and sub-trajectory isolation, while other data points are processed according to standard anonymization procedures. This local quality approach ensures that privacy protection does not uniformly degrade data utility.

Inventive Principle:
Principle #3Local quality

2Loss of information

If all trajectory data points are retained, then data utility is maximized, but user privacy is compromised

Engineering Contradiction:
Improvedata utilityVSAvoiduser privacy
Core Design Contradiction:
Loss of informationVSObject-affected harmful factors

Solution Approach 1:

The patent extracts high-value data points from the overall trajectory and places them in separate sub-trajectories with gaps. This extraction allows the system to separate sensitive information that requires privacy protection from data that can be openly utilized, thereby maximizing data utility while protecting user privacy through selective retention.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If trajectory anonymization discards high-value data points, then privacy is protected, but service quality and customer satisfaction decrease

Engineering Contradiction:
Improveprivacy protectionVSAvoidservice quality
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

By segmenting the trajectory into sub-trajectories centered around high-value data points, the system preserves these points while maintaining privacy protection. This segmentation enables location-based services to access and utilize high-value data for improved service quality without compromising user privacy, as the gaps and sub-trajectory structure prevent direct identification.

Inventive Principle:
Principle #1Segmentation

4Object-affected harmful factors

If gaps are introduced between trajectory segments, then anonymity is enhanced, but data completeness is reduced

Engineering Contradiction:
ImproveanonymityVSAvoiddata completeness
Core Design Contradiction:
Object-affected harmful factorsVSLoss of information

Solution Approach 1:

The patent introduces gaps selectively around high-value data points rather than uniformly across the entire trajectory. This local application of gaps enhances anonymity where it matters most (around sensitive information) while minimizing the overall loss of data completeness. The gaps are precisely targeted to protect privacy without unnecessarily discarding useful information.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3992828B1Method, apparatus, and computer program product for anonymizing trajectories
Publication Date: 2024.08.28 HERE GLOBAL BV
  • EP3992828B1 patent drawingFigure 1
  • EP3992828B1 patent drawingFigure 2
  • EP3992828B1 patent drawingFigure 3~3C

AI summary

Embodiments described herein relate to anonymizing of trajectories of mobile devices through the introduction of gaps between sub-trajectories. Methods may include: receiving a set of probe data points defining a trajectory; identifying a temporal length range of sub-trajectories; receiving a mode, where the mode is established based on a preceding set of probe data points defining a trajectory, where the mode includes an indication of whether to generate a sub-trajectory or a gap from the beginning of the received set of probe data points; and establishing at least one sub-trajectory including a sub-set of the set of probe data points, where the at least one sub-trajectory is established to satisfy the temporal length range of sub-trajectories.