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A Greedy Approach Towards Parsimonious Temporal Aggregation


Gordevicius, Juozas; Gamper, Johann; Böhlen, Michael Hanspeter (2008). A Greedy Approach Towards Parsimonious Temporal Aggregation. In: TIME 2008: 15th International Symposium on Temporal Representation and Reasoning, Montreal, QC, 16 June 2008 - 18 June 2008, 88-92.

Abstract

Temporal aggregation is a crucial operator in temporal databases and has been studied in various flavors. In instant temporal aggregation (ITA) the aggregate value at time instant t is computed from the tuples that hold at t. ITA considers the distribution of the input data and works at the smallest time granularity, but the result size depends on the input timestamps and can get twice as large as the input relation. In span temporal aggregation (STA) the user specifies the timestamps over which the aggregates are computed and thus controls the result size. In this paper we introduce a new temporal aggregation operator, called greedy parsimonious temporal aggregation (PTAg), which combines features from ITA and STA. The operator extends and approximates ITA by greedily merging adjacent tuples with similar aggregate values until the number of result tuples is sufficiently small, which can be controlled by the application. Thus, PTAg considers the distribution of the data and allows to control the result size. Our empirical evaluation on real world data shows good results: considerable reductions of the result size introduce small errors only.

Temporal aggregation is a crucial operator in temporal databases and has been studied in various flavors. In instant temporal aggregation (ITA) the aggregate value at time instant t is computed from the tuples that hold at t. ITA considers the distribution of the input data and works at the smallest time granularity, but the result size depends on the input timestamps and can get twice as large as the input relation. In span temporal aggregation (STA) the user specifies the timestamps over which the aggregates are computed and thus controls the result size. In this paper we introduce a new temporal aggregation operator, called greedy parsimonious temporal aggregation (PTAg), which combines features from ITA and STA. The operator extends and approximates ITA by greedily merging adjacent tuples with similar aggregate values until the number of result tuples is sufficiently small, which can be controlled by the application. Thus, PTAg considers the distribution of the data and allows to control the result size. Our empirical evaluation on real world data shows good results: considerable reductions of the result size introduce small errors only.

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Additional indexing

Item Type:Conference or Workshop Item (Paper), refereed, original work
Communities & Collections:03 Faculty of Economics > Department of Informatics
Dewey Decimal Classification:000 Computer science, knowledge & systems
Language:English
Event End Date:18 June 2008
Deposited On:01 Jun 2012 15:34
Last Modified:05 Apr 2016 15:26
Publisher:IEEE
Publisher DOI:10.1109/TIME.2008.24
Other Identification Number:merlin-id:2300
Permanent URL: http://doi.org/10.5167/uzh-56222

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