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2007
IEEE

MAGIC: A Multi-Activity Graph Index for Activity Detection

14 years 6 months ago
MAGIC: A Multi-Activity Graph Index for Activity Detection
Suppose we are given a set A of activities of interest, a set O of observations, and a probability threshold p. We are interested in finding the set of all pairs (a, O ), where a ∈ A and O ⊆ O, that minimally validate the fact that an instance of activity a occurs in O with probability p or more. The novel contribution of this paper is the notion of the multi-activity graph index (MAGIC), which can index very large numbers of observations from interleaved activities and quickly retrieve completed instances of the monitored activities. We introduce two complexity reducing restrictions of the problem (which takes exponential time) and develop algorithms for each. We experimentally evaluate our exponential algorithm as well as the restricted algorithms on both synthetic data and a real (depersonalized) travel data set consisting of 5.5 million observations. Our experiments show that MAGIC consumes reasonable amounts of memory and can retrieve completed instances of activities in jus...
Massimiliano Albanese, Andrea Pugliese, V. S. Subr
Added 03 Jun 2010
Updated 03 Jun 2010
Type Conference
Year 2007
Where IRI
Authors Massimiliano Albanese, Andrea Pugliese, V. S. Subrahmanian, Octavian Udrea
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