TY - GEN
T1 - An Efficient Index for Reachability Queries in Public Transport Networks
AU - Tesfaye, Bezaye
AU - Augsten, Nikolaus
AU - Pawlik, Mateusz
AU - Böhlen, Michael Hanspeter
AU - Jensen, Christian S.
PY - 2020
Y1 - 2020
N2 - Computing path queries such as the shortest path in public transport networks is challenging because the path costs between nodes change over time. A reachability query from a node at a given start time on such a network retrieves all points of interest (POIs) that are reachable within a given cost budget. Reachability queries are essential building blocks in many applications, for example, group recommendations, ranking spatial queries, or geomarketing. We propose an efficient solution for reachability queries in public transport networks. Currently, there are two options to solve reachability queries. (1) Execute a modified version of Dijkstra’s algorithm that supports time-dependent edge traversal costs; this solution is slow since it must expand edge by edge and does not use an index. (2) Issue a separate path query for each single POI, i.e., a single reachability query requires answering many path queries. None of these solutions scales to large networks with many POIs. We propose a novel and lightweight reachability index. The key idea is to partition the network into cells. Then, in contrast to other approaches, we expand the network cell by cell. Empirical evaluations on synthetic and real-world networks confirm the efficiency and the effectiveness of our index-based reachability query solution.
AB - Computing path queries such as the shortest path in public transport networks is challenging because the path costs between nodes change over time. A reachability query from a node at a given start time on such a network retrieves all points of interest (POIs) that are reachable within a given cost budget. Reachability queries are essential building blocks in many applications, for example, group recommendations, ranking spatial queries, or geomarketing. We propose an efficient solution for reachability queries in public transport networks. Currently, there are two options to solve reachability queries. (1) Execute a modified version of Dijkstra’s algorithm that supports time-dependent edge traversal costs; this solution is slow since it must expand edge by edge and does not use an index. (2) Issue a separate path query for each single POI, i.e., a single reachability query requires answering many path queries. None of these solutions scales to large networks with many POIs. We propose a novel and lightweight reachability index. The key idea is to partition the network into cells. Then, in contrast to other approaches, we expand the network cell by cell. Empirical evaluations on synthetic and real-world networks confirm the efficiency and the effectiveness of our index-based reachability query solution.
KW - Public transport networks
KW - Reachability queries
KW - Spatial network databases
KW - Temporal graphs
UR - http://www.scopus.com/inward/record.url?scp=85090097752&partnerID=8YFLogxK
U2 - 10.1007/978-3-030-54832-2_5
DO - 10.1007/978-3-030-54832-2_5
M3 - Article in proceeding
SN - 978-3-030-54831-5
T3 - Lecture Notes in Computer Science (LNCS)
SP - 34
EP - 48
BT - ADBIS 2020: Advances in Databases and Information Systems
A2 - Darmont, Jérôme
A2 - Novikov, Boris
A2 - Wrembel, Robert
PB - Springer
T2 - European Conference on Advances in Databases and Information Systems 2020
Y2 - 25 August 2020 through 27 August 2020
ER -