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The ACM Journal of Experimental Algorithmics


Volume 5, Article 12, 2000


Dijkstra's Algorithm On-Line: An Empirical Case Study from Public Railroad Transport

by

Frank Schulz

and

Dorothea Wagner

and

Karsten Weihe

http://www.jea.acm.org/2000/SchulzDijkstra/

Abstract:

Traffic information systems are among the most prominent real-world applications of Dijkstra's algorithm for shortest paths. We consider the scenario of a central information server in the realm of public railroad transport on wide-area networks. Such a system has to process a large number of on-line queries in real time. In practice, this problem is usually solved by heuristic variations of Dijkstra's algorithm, which do not guarantee optimality. We report results from a pilot study, in which we focused on the travel time as the only optimization criterion. In this study, various optimality-preserving speed-up techniques for Dijkstra's algorithm were analysed empirically. This analysis was based on the timetable data of all German trains and on a ``snapshot'' of half a million customer queries.

Received
Accepted
Final Revision
Published




Last updated and validated October 11, 2001, by editor@jea.acm.org

Last updated and validated October 10, 2001, by editor@jea.acm.org