Timetable information and shortest paths
نویسنده
چکیده
منابع مشابه
Using Multi-level Graphs for Timetable Information in Railway Systems
In many fields of application, shortest path finding problems in very large graphs arise. Scenarios where large numbers of on-line queries for shortest paths have to be processed in real-time appear for example in traffic information systems. In such systems, the techniques considered to speed up the shortest path computation are usually based on precomputed information. One approach proposed o...
متن کاملMaintenance of Multi-level Overlay Graphs for Timetable Queries
In railways systems the timetable is typically represented as a weighted digraph on which itinerary queries are answered by shortest path algorithms, usually running Dijkstra’s algorithm. Due to the continuously growing size of real-world graphs, there is a constant need for faster algorithms and many techniques have been devised to heuristically speed up Dijkstra’s algorithm. One of these tech...
متن کاملTimetable Information Updating in Case of Delays : Modeling
The timetable information problem can be solved by computing shortest paths in special graphs built from timetable data. In general, two models exist: the time-dependent and time-expanded network. In a recent work, both models are compared with respect to advantages and disadvantages on a theoretical and a practical framework. In addition, an extensive experimental evaluation reveals further di...
متن کاملContraction of Timetable Networks with Realistic Transfers
We successfully contract timetable networks with realistic transfer times. Contraction gradually removes nodes from the graph and adds shortcuts to preserve shortest paths. This reduces query times to 1ms with preprocessing times around 6 minutes on all tested instances. We achieve this by an improved contraction algorithm and by using a station graph model. Every node in our graph has a one-to...
متن کاملEngineering Graph-Based Models for Dynamic Timetable Information Systems
Many efforts have been done in the last years to model public transport timetables in order to find optimal routes. The proposed models can be classified into two types: those representing the timetable as an array, and those representing it as a graph. The array-based models have been shown to be very effective in terms of query time, while the graph-based models usually answer queries by comp...
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تاریخ انتشار 2005