Trajectory Similarity Search With Synchronized Space-Time Matching
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Solution Overview
Problem
Efficiently searching a large database of trajectory data for similar trajectories to a query trajectory is challenging due to traditional methods computing spatial and temporal similarities independently, leading to inconsistent overall similarity measurements.
Innovation Solution
A method that synchronously measures similarity by matching spatial distance against time difference, using grid-based indexing and partitioning of trajectories to improve search efficiency, allowing for effective identification of similar trajectories.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional methods compute spatial and temporal similarities independently, then the computation process is simple, but the overall similarity measurement becomes inconsistent
Solution Approach 1:
The patent merges spatial similarity and temporal similarity computations into a unified synchronized measurement process. Instead of computing spatial and temporal similarities independently and then combining them, the invention integrates both measurements to occur simultaneously, ensuring consistency in the overall similarity assessment between query trajectory and database trajectories.
Solution Approach 2:
The patent introduces dynamic synchronization between spatial and temporal measurements. The computation adapts by adjusting the correspondence between spatial points and temporal points based on their actual distances and time differences, creating a dynamic measurement process that maintains consistency across different trajectory pairs with varying speeds and patterns.
2Quantity of substance
If the trajectory database is large, then more trajectories are available for analysis, but the search time increases
Solution Approach 1:
The patent applies preliminary action by pre-computing and storing distance and time difference information in index structures before actual similarity searches are performed. This preprocessing allows the system to quickly retrieve and compare pre-calculated values during search operations, significantly reducing search time for large trajectory databases.
Solution Approach 2:
The patent segments the large trajectory database into manageable units and implements partitioning strategies. By dividing the database and using grid-based spatial indexing, the system can efficiently locate and compare only relevant trajectory segments rather than processing entire trajectories, reducing the effective search space and time.
3Measurement precision
If synchronized measurement of spatial and temporal similarity is implemented, then measurement consistency is improved, but computational complexity increases
Solution Approach 1:
The patent changes the parameters of computation by using pre-calculated distance and time difference values stored in index structures. Instead of computing Euclidean distances and time differences from raw coordinate data during similarity searches, the system retrieves pre-computed parameters, reducing the computational power required for synchronized measurements.
Solution Approach 2:
The patent introduces index structures as intermediaries between the raw trajectory data and the similarity computation process. These indexes store pre-processed spatial and temporal information, acting as a mediator that provides ready-to-use measurements for synchronized comparison, thereby reducing the computational burden during actual similarity searches.
Data Source
AI summary
A computer-implemented method, a computer system, and a computer program product for trajectory similarity search is provided. The present invention may include, in response to receiving, by one or more processors, a search request for at least one trajectory similar to a query trajectory, determining, by one or more processors, a respective similarity between a query trajectory and a plurality of trajectories by calculating, in a synchronized way, a spatial distance measure and a time difference measure between the query trajectory and the plurality of trajectories. The present invention may further include, identifying, by one or more processors, the at least one trajectory from the plurality of trajectories based on the respective similarity between the query trajectory and the plurality of trajectories.