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ICTCS
2005
Springer

Improved Algorithms for Polynomial-Time Decay and Time-Decay with Additive Error

14 years 3 months ago
Improved Algorithms for Polynomial-Time Decay and Time-Decay with Additive Error
Abstract. We consider the problem of maintaining polynomial and exponential decay aggregates of a data stream, where the weight of values seen from the stream diminishes as time elapses. These types of aggregation were discussed by Cohen and Strauss in [2], and can be used in many applications in which the relative value of streaming data decreases since the time the data was seen. Some recent work and space efficient algorithms were developed for time-decaying aggregations, and in particular polynomial and exponential decaying aggregations. All of the work done so far has maintained multiplicative approximations for the aggregates. In this paper we present the first O(log N) space algorithm for the polynomial decay under a multiplicative approximation, matching a lower bound. In addition, we explore and develop algorithms and lower bounds for approximations allowing an additive error in addition to the multiplicative error. We show that in some cases, allowing an additive error can d...
Tsvi Kopelowitz, Ely Porat
Added 27 Jun 2010
Updated 27 Jun 2010
Type Conference
Year 2005
Where ICTCS
Authors Tsvi Kopelowitz, Ely Porat
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