Arménio Antunes, December 2012

Análise Espacial de Grandes Quantidades de Dados de Movimento Usando Técnicas de Clustering Baseadas em Densidade, Maribel Yasmina Santos/Adriano Moreira (superv.), Universidade do Minho, December 2012.
Keywords: clustering; shared nearest neighbour; movement data

Abstract: Current positioning and sensing technologies enable the collection of very large spatio-temporal data sets. When analysing movement data, researchers often resort to clustering techniques to extract useful patterns from these data. Density-based clustering algorithms, although being very adequate to the analysis of this type of data, can be very inefficient when analysing huge amounts of data. The SNN (Shared Nearest Neighbour) algorithm presents low efficiency when dealing with high quantities of data due to its complexity evaluated in the worst case by O(n2). This work presents a clustering method, based on the SNN algorithm that significantly reduces the processing time by segmenting the spatial dimension of the data into a set of cells, and by minimizing the number of cells that have to be visited while searching for the nearest neighbours of each vector.