Multimodal Itinerary Transfer Pruning for User-Selected Modes
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Solution Overview
Problem
Existing journey planners for multimodal transportation networks struggle to accurately account for user preferences in mode selection, leading to suboptimal solutions due to excessive pruning of feasible transfers based on all possible modes, which is inefficient and time-consuming.
Innovation Solution
A method for preprocessing feasible transfers within a multimodal transportation network that considers user-selected modes, ensuring only transfers beneficial for those modes are retained, thereby optimizing the pruning process and reducing exploration time while maintaining optimal results.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If all feasible transfers are considered in journey planning, then the completeness of route options is improved, but the computation time and complexity increase significantly
Solution Approach 1:
The patent segments the set of all feasible transfers into mode-specific subsets. For each transportation mode (e.g., subway, bus, tram), a separate transfer set is constructed containing only transfers involving that mode. This segmentation allows the algorithm to process smaller, mode-specific subsets rather than the complete set of all transfers, reducing computation time while maintaining the ability to provide complete route options across multiple modes.
2Productivity
If pruning is applied to reduce the set of feasible transfers, then the computation speed is improved, but the accuracy of optimal route selection deteriorates
Solution Approach 1:
The patent applies local quality by creating mode-specific transfer sets with different characteristics for each transportation mode. Each mode's transfer set is pruned according to mode-specific criteria and user preferences for that mode, rather than applying a uniform pruning approach to all transfers. This ensures that the pruning process maintains accuracy for each mode while improving overall computation speed.
Solution Approach 2:
The patent implements dynamic pruning where the set of feasible transfers is adaptively adjusted based on user-specified mode preferences. The algorithm dynamically constructs transfer sets by including only transfers involving modes that the user has indicated preference for, rather than statically considering all possible transfers. This dynamic approach maintains solution accuracy for preferred modes while significantly reducing the search space.
3Reliability
If the complete set of feasible transfers is processed, then all possible optimal itineraries are found, but the system becomes inefficient and time-consuming
Solution Approach 1:
The patent performs preliminary action by pre-filtering and organizing transfers into mode-specific sets before the main route-finding process. User preferences for different transportation modes are incorporated in advance to construct reduced transfer sets. This preliminary organization ensures that when the algorithm searches for optimal itineraries, it only processes relevant transfers, maintaining completeness of results while dramatically improving system efficiency.
Data Source
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AI summary
The present invention relates to a method for preprocessing a set of feasible transfers within a multimodal transportation network of predetermined stations, comprising, for each trip in the multimodal transportation network hereafter called origin trip: (a) For each station pti of the origin trip (t), computing at this station pti an earliest arrival/change time associated with all transportation modes (m) of the multimodal transportation network; (b) For at least one transfer of the set of feasible transfers from a station pti on said origin trip (t) to a reachable station puj on a target trip (u), computing, at each station puk>j of the target trip (u) after said reachable station puj, a value of the earliest arrival/change time specifically associated with the transportation mode (mu) of the multimodal transportation network used by said target trip (u); (c) Removing said transfer only if determining that each computed value of the earliest arrival/change time is never improved by the transfer; (d) Outputting the set of feasible transfers for computing at least one itinerary in the multimodal transportation network. The invention further relates to a method for computing at least one itinerary from a departure location to an arrival location, wherein said itinerary is restricted to a combination of transportation modes selected among possible transportation modes of the multimodal transportation network, comprising preprocessing said set of feasible transfers within the multimodal transportation network so as to obtain a subset of feasible transfers, and considering only transfers from the subset of feasible transfers between trips using the selected transportation modes.