Route Search Apparatus Using Weighted Variance Cost Function
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Solution Overview
Problem
Existing route search technologies, such as those described in JP 2012-141145A, lack flexibility in variance value calculations, leading to inefficient processing, high costs, and reduced convenience, as they use fixed variance values for route determination.
Innovation Solution
A route search apparatus that calculates an overall cost value based on average cost values and variance values, incorporating a weight coefficient to allow for flexible route search, determining recommended routes by balancing average cost and variance considerations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fixed variance values are used for each link, then the calculation process is simple, but the route search lacks flexibility and cannot adapt to different user needs
Solution Approach 1:
The patent applies dynamics by making the variance value adjustable rather than fixed. The system allows users to dynamically change the weight coefficient (lambda) to balance between average cost and variance, enabling flexible route search that adapts to different user needs while maintaining a manageable calculation framework through the unified cost function.
Solution Approach 2:
The patent changes the parameter of variance value from a fixed constant to a variable that can be adjusted through the weight coefficient. By modifying the weight coefficient in the cost function, users can control the degree to which variance affects the route search, providing adaptability without requiring complete recalculation of the system architecture.
2Measurement precision
If only reference travel time is considered, then the processing is efficient, but the route determination lacks accuracy in terms of travel time reliability
Solution Approach 1:
The patent merges the average cost value and variance value into a single unified cost function through the weight coefficient. This combination allows the system to simultaneously consider both travel time efficiency and reliability, producing a comprehensive route determination that balances processing efficiency with measurement precision.
Solution Approach 2:
The patent uses the weight coefficient as a parameter to control the contribution of variance to the overall cost. By adjusting this parameter, the system can flexibly balance between considering only average cost (for efficiency) and incorporating variance (for reliability), allowing optimal trade-off depending on user requirements.
3Measurement precision
If variance value is incorporated into route search, then the route determination becomes more accurate, but the calculation complexity increases
Solution Approach 1:
The patent combines average cost and variance into a single cost function with a weight coefficient, simplifying the overall calculation structure. Rather than maintaining separate complex evaluation systems, the unified function integrates both factors multiplicatively, reducing computational complexity while preserving route determination accuracy.
Data Source
AI summary
A route search apparatus configured to search a route from a set place of departure to a set destination comprises network data that includes nodes and links representing a road network, an average cost value indicating an average of travel time of each of the links, and a variance value indicating a degree of variance of the travel time, and a route searcher configured to determine the route from the place of departure to the destination as a recommended route, based on the average cost value, the variance value and a weight coefficient of the variance value.