Title
Finding long and similar parts of trajectories
Abstract
A natural time-dependent similarity measure for two trajectories is their average distance at corresponding times. We give algorithms for computing the most similar subtrajectories under this measure, assuming the two trajectories are given as two polygonal, possibly self-intersecting lines. When a minimum duration is specified for the subtrajectories, and they must start at exactly corresponding times in the input trajectories, we give a linear-time algorithm for computing the starting time and duration of the most similar subtrajectories. The algorithm is based on a result of independent interest: We present a linear-time algorithm to find, for a piece-wise monotone function, an interval of at least a given length that has minimum average value. When the two subtrajectories can start at different times in the two input trajectories, it appears difficult to give an exact algorithm for the most similar subtrajectories problem, even if the duration of the desired two subtrajectories is fixed to some length. We show that the problem can be solved approximately, and with a performance guarantee. More precisely, we present (1 + ε)-approximation algorithms for computing the most similar subtrajectories of two input trajectories for the case where the duration is specified, and also for the case where only a minimum on the duration is specified.
Year
DOI
Venue
2011
10.1016/j.comgeo.2011.05.004
Computational Geometry: Theory and Applications
Keywords
Field
DocType
minimum average value,trajectory analysis,linear-time algorithm,approximation algorithm,moving objects,similarity measure,natural time-dependent similarity measure,minimum duration,corresponding time,fixed duration,similar part,exact algorithm,average distance,similar subtrajectories,monotone function
Discrete mathematics,Monotonic function,Data mining,Polygon,Similarity measure,Exact algorithm,Algorithm,Performance guarantee,Mathematics
Journal
Volume
Issue
ISSN
44
9
Computational Geometry: Theory and Applications
Citations 
PageRank 
References 
25
0.95
32
Authors
4
Name
Order
Citations
PageRank
Kevin Buchin152152.55
Maike Buchin245833.97
Marc J. van Kreveld31702166.91
Jun Luo422226.61