Parallel Trajectory-to-Location Join

Shuo Shang, Lisi chen, Kai Zheng, Christian S. Jensen, Zhewei Wei, Panos Kalnis

Research output: Contribution to journalArticlepeer-review

65 Scopus citations


The matching between trajectories and locations, called Trajectory-to-Location join (TL-Join), is fundamental functionality in spatiotemporal data management. Given a set of trajectories, a set of locations, and a threshold θ, the TL-Join finds all (trajectory, location) pairs from the two sets with spatiotemporal correlation above θ. This join targets diverse applications, including location recommendation, event tracking, and trajectory activity analyses. We address three challenges in relation to the TL-Join: how to define the spatiotemporal correlation between trajectories and locations, how to prune the search space effectively when computing the join, and how to perform the computation in parallel. Specifically, we define new metrics to measure the spatiotemporal correlation between trajectories and locations. We develop a novel parallel collaborative (PCol) search method based on a divide-and-conquer strategy. For each location $o$ , we retrieve the trajectories with high spatiotemporal correlation to $o$ , and then we merge the results. An upper bound on the spatiotemporal correlation and a heuristic scheduling strategy are developed to prune the search space. The trajectory searches from different locations are independent and are performed in parallel, and the result merging cost is independent of the degree of parallelism. Studies of the performance of the developed algorithms using large spatiotemporal data sets are reported.
Original languageEnglish (US)
Pages (from-to)1194-1207
Number of pages14
JournalIEEE Transactions on Knowledge and Data Engineering
Issue number6
StatePublished - Jul 10 2018

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KAUST Repository Item: Exported on 2020-10-01


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