Computing Continuous Dynamic Time Warping of Time Series in Polynomial Time

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Dynamic Time Warping is arguably the most popular similarity measure for time series, where we define a time series to be a one-dimensional polygonal curve. The drawback of Dynamic Time Warping is that it is sensitive to the sampling rate of the time series. The Fréchet distance is an alternative that has gained popularity, however, its drawback is that it is sensitive to outliers. Continuous Dynamic Time Warping (CDTW) is a recently proposed alternative that does not exhibit the aforementioned drawbacks. CDTW combines the continuous nature of the Fréchet distance with the summation of Dynamic Time Warping, resulting in a similarity measure that is robust to sampling rate and to outliers. In a recent experimental work of Brankovic et al., it was demonstrated that clustering under CDTW avoids the unwanted artifacts that appear when clustering under Dynamic Time Warping and under the Fréchet distance. Despite its advantages, the major shortcoming of CDTW is that there is no exact algorithm for computing CDTW, in polynomial time or otherwise. In this work, we present the first exact algorithm for computing CDTW of one-dimensional curves. Our algorithm runs in time O(n5) for a pair of one-dimensional curves, each with complexity at most n. In our algorithm, we propagate continuous functions in the dynamic program for CDTW, where the main difficulty lies in bounding the complexity of the functions. We believe that our result is an important first step towards CDTW becoming a practical similarity measure between curves.

Original languageEnglish
Title of host publication38th International Symposium on Computational Geometry, SoCG 2022
EditorsXavier Goaoc, Michael Kerber
Number of pages16
PublisherSchloss Dagstuhl- Leibniz-Zentrum fur Informatik GmbH, Dagstuhl Publishing
Publication date2022
Article number22
ISBN (Electronic)9783959772273
DOIs
Publication statusPublished - 2022
Event38th International Symposium on Computational Geometry, SoCG 2022 - Berlin, Germany
Duration: 7 Jun 202210 Jun 2022

Conference

Conference38th International Symposium on Computational Geometry, SoCG 2022
LandGermany
ByBerlin
Periode07/06/202210/06/2022
SeriesLeibniz International Proceedings in Informatics, LIPIcs
Volume224
ISSN1868-8969

Bibliographical note

Publisher Copyright:
© Kevin Buchin, Andr Nusser, and Sampson Wong; licensed under Creative Commons License CC-BY 4.0

    Research areas

  • Computational Geometry, Continuous Dynamic Time Warping, Curve Similarity, Dynamic Time Warping, Fréchet distance

ID: 342674199