Point set stratification and Delaunay depth

  • Authors:
  • Manuel Abellanas;Mercè Claverol;Ferran Hurtado

  • Affiliations:
  • Departamento de Matemática Aplicada, Facultad de Informática, Universidad Politécnica de Madrid, Boadilla del Monte, 28660 Madrid, Spain;Departament de Matemítica Aplicada IV, Universitat Politècnica de Catalunya, EPSEVG. Avda. Víctor Balaguer s/n 08800 Vilanova i La Geltrú, Spain;Departament de Matemítica Aplicada II, Universitat Politècnica de Catalunya, Jordi Girona 1-3, 08034 Barcelona, Spain

  • Venue:
  • Computational Statistics & Data Analysis
  • Year:
  • 2007
  • DEpthLAUNAY

    ICMS'06 Proceedings of the Second international conference on Mathematical Software

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Abstract

In the study of depth functions it is important to decide whether a depth function is required to be sensitive to multimodality. An analysis of the Delaunay depth function shows that it is sensitive to multimodality. This notion of depth can be compared to other depth functions such as the convex and location depths. The stratification that Delaunay depth induces in the point set (layers) and in the whole plane (levels) is investigated. An algorithm for computing the Delaunay depth contours associated with a point set in the plane is developed. The worst case and expected complexities of the algorithm are O(nlog^2n) and O(nlogn), respectively. The depth of a query point p with respect to a data set S in the plane is the depth of p in S@?{p}. The Delaunay depth can be computed in O(nlogn) time, which is proved to be optimal, when S and p are given in the input.