Naslov
Method and device for determining the length of a shortest path in a network

Autori
Bast, Holger ; Funke, Stefan ; Matijević, Domagoj

Broj patenta
US 2009/0040931 A1

Godina
2009

Datum patenta
02.12.2009.

Nositelj prava
Max-Planck-Gesellschaft zur Forderung der Wissenschaften e.V. (Munchen, DE), ,

Sažetak
We introduce the concept of transit nodes, as a means for preprocessing a road network, with given coordinates for each node and a travel time for each edge, such that point-to-point shortest-path queries can be answered extremely fast. The transit nodes are a set of nodes as small as possible with the property that every shortest path that is non-local in the sense that it covers a certain not too small euclidean distance passes through at least on of these nodes. With such a set and precomputed distances from each node in the graph to its few, closest transit nodes, every non-local shortest path query becomes a simple matter of combining information from a few table lookups. For the US road network, which has about 24 million nodes and 58 million edges, we achieve a worst-case query processing time of about 10 microseconds (not milliseconds) for 99% of all queries. This improves over the best previously reported times by two orders of magnitude.

Izvorni jezik
Engleski

Znanstvena područja
Matematika, Računarstvo

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