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Discovering Frequent Event Patterns with Multiple Granularities in Time Sequences
March/April 1998 (vol. 10 no. 2)
pp. 222-237

Abstract—An important usage of time sequences is to discover temporal patterns. The discovery process usually starts with a user-specified skeleton, called an event structure, which consists of a number of variables representing events and temporal constraints among these variables; the goal of the discovery is to find temporal patterns, i.e., instantiations of the variables in the structure that appear frequently in the time sequence. This paper introduces event structures that have temporal constraints with multiple granularities, defines the pattern-discovery problem with these structures, and studies effective algorithms to solve it. The basic components of the algorithms include timed automata with granularities (TAGs) and a number of heuristics. The TAGs are for testing whether a specific temporal pattern, called a candidate complex event type, appears frequently in a time sequence. Since there are often a huge number of candidate event types for a usual event structure, heuristics are presented aiming at reducing the number of candidate event types and reducing the time spent by the TAGs testing whether a candidate type does appear frequently in the sequence. These heuristics exploit the information provided by explicit and implicit temporal constraints with granularity in the given event structure. The paper also gives the results of an experiment to show the effectiveness of the heuristics on a real data set.

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Index Terms:
Data mining, knowledge discovery, time sequences, temporal databases, time granularity, temporal constraints, temporal patterns.
Claudio Bettini, X. Sean Wang, Sushil Jajodia, Jia-Ling Lin, "Discovering Frequent Event Patterns with Multiple Granularities in Time Sequences," IEEE Transactions on Knowledge and Data Engineering, vol. 10, no. 2, pp. 222-237, March-April 1998, doi:10.1109/69.683754
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